Pain Control and Monitoring in Surgery
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Questions and Answers

What is the primary goal of pain control in the postoperative setting?

  • To eliminate all sources of pain permanently
  • To provide pain relief with minimal side effects on homeostasis (correct)
  • To maximize the dosage of analgesics administered post-surgery
  • To ensure complete sedation during and after the procedure

    • Which of the following factors does NOT influence the degree of pain experienced by a patient?

  • Age of the patient
  • Surgical site
  • Anesthetic technique
  • Type of insurance held by the patient (correct)

    • What is a requirement for a patient to use Patient Controlled Analgesia (PCA)?

  • Patient needs to have a history of opioid addiction
  • Patient should be under general anesthesia during administration
  • Patient must be able to self-administer via oral medications
  • Patient must be oriented and have IV, SC, or epidural access (correct)

    • Which monitoring device is primarily used to measure the oxygen saturation of arterial blood?

    <p>Pulse oximeter</p> Signup and view all the answers

    What can cause inaccurate readings in a pulse oximeter?

    <p>Dyes, hypotension, or vasoconstriction</p> Signup and view all the answers

    What is the purpose of having routine monitors during anesthesia?

    <p>To support the anesthetist's vigilance and enhance safety</p> Signup and view all the answers

    Which analgesic method aims to prevent or reduce noxious stimuli before surgery?

    <p>Preemptive analgesia</p> Signup and view all the answers

    Which of the following is NOT a common monitoring device used in anesthesia?

    <p>Blood glucose monitor</p> Signup and view all the answers

    Which complication is associated with muscle necrosis and weakness during anesthesia?

    <p>Myoglobinuric renal failure</p> Signup and view all the answers

    What is the primary reason for avoiding elective surgery within 6 months of a myocardial infarction (MI)?

    <p>Increased risk of reinfarction</p> Signup and view all the answers

    Which of the following is NOT a recommended prevention strategy for malignant hyperthermia?

    <p>Using dantrolene prophylaxis routinely</p> Signup and view all the answers

    In the event of metabolic or physiologic derangements during anesthesia management, which action is critical?

    <p>Control of body temperature</p> Signup and view all the answers

    The severity of gastric aspiration is primarily influenced by which of the following factors?

    <p>Volume and quality of the aspirate</p> Signup and view all the answers

    Which receptor class is primarily responsible for sedation and spinal analgesia?

    <p>Kappa receptors</p> Signup and view all the answers

    What is one of the central nervous system effects of morphine?

    <p>Respiratory depression</p> Signup and view all the answers

    What is the effect of opioids on the gastrointestinal system?

    <p>Constipation</p> Signup and view all the answers

    Which of the following is NOT an indication for opioid use?

    <p>Management of anxiety disorders</p> Signup and view all the answers

    What is a common cardiovascular effect of morphine?

    <p>Vasodilation</p> Signup and view all the answers

    Which receptor class is associated with mood changes primarily?

    <p>Delta receptors</p> Signup and view all the answers

    What is the mode of administration that opioids can be given?

    <p>Intravenous, intramuscular, or oral</p> Signup and view all the answers

    Which of the following effects is directly linked to opioid-induced CNS excitation?

    <p>Miosis</p> Signup and view all the answers

    What is an effect of morphine on the respiratory system?

    <p>Central respiratory depression</p> Signup and view all the answers

    What impact do opioids have on bladder function?

    <p>Urinary retention</p> Signup and view all the answers

    What does the capnometer primarily measure?

    <p>Exhaled carbon dioxide levels</p> Signup and view all the answers

    Which monitor is specifically used to assess muscle relaxation during anesthesia?

    <p>Peripheral nerve stimulators</p> Signup and view all the answers

    What is the primary goal of achieving amnesia in general anesthesia?

    <p>To prevent memory of the procedure</p> Signup and view all the answers

    Which monitor would be used for continuous blood pressure monitoring?

    <p>Arterial line</p> Signup and view all the answers

    What is the purpose of the Swan-Ganz catheter?

    <p>To measure mixed venous blood gases and cardiac output</p> Signup and view all the answers

    Which of the following is NOT one of the '6 A's of Anesthesia'?

    <p>Sympathetic activation</p> Signup and view all the answers

    Which measurement tool is used to identify and measure inhaled and exhaled gases?

    <p>Mass spectrometer</p> Signup and view all the answers

    What is the function of the blood pressure cuff?

    <p>To measure arterial blood pressure</p> Signup and view all the answers

    What condition is indicated by a PO2 of 60 mmHg corresponding to a Hb saturation of 90%?

    <p>Mild hypoxemia</p> Signup and view all the answers

    Which device is utilized for assessing the adequacy of ventilation?

    <p>Capnometer</p> Signup and view all the answers

    What is a notable risk associated with Nitrous Oxide during emergence from anesthesia?

    <p>Dilution of O2 due to rapid diffusion from blood</p> Signup and view all the answers

    Which of the following volatile inhalational agents is least likely to cause postoperative hepatitis?

    <p>Halothane</p> Signup and view all the answers

    What should be administered during recovery after Nitrous Oxide administration?

    <p>100% Oxygen</p> Signup and view all the answers

    Which adverse effect is primarily associated with chronic use of volatile inhalational agents?

    <p>Bone marrow depression</p> Signup and view all the answers

    What specific danger does Nitrous Oxide pose in patients with trapped air in closed spaces?

    <p>Increased pressure and volume</p> Signup and view all the answers

    What major toxicity concern is associated with volatile inhalational agents?

    <p>Decreased autonomic functions</p> Signup and view all the answers

    Which volatile inhalational agent is likely to have a faster emergence profile?

    <p>Sevoflurane</p> Signup and view all the answers

    What is a potential central nervous system effect of volatile inhalational agents?

    <p>Decreased heart rate</p> Signup and view all the answers

    Halothane can rarely be implicated in which postoperative complication?

    <p>Hepatitis</p> Signup and view all the answers

    What is the risk of administering Nitrous Oxide to patients with closed air spaces?

    <p>Rupture of air-filled cavities</p> Signup and view all the answers

    What is the primary function of colloid infusion in fluid management?

    <p>To expand the intravascular volume</p> Signup and view all the answers

    Which IV fluid solution has the highest sodium concentration?

    <p>0.9 NS</p> Signup and view all the answers

    In which IV fluid is lactate converted to bicarbonate for buffering capacity?

    <p>Ringer's Lactate</p> Signup and view all the answers

    What is the osmolarity range for the majority of IV fluids typically used?

    <p>280-310 mOsm/L</p> Signup and view all the answers

    Which electrolytes are present in D5W IV fluid?

    <p>Only glucose</p> Signup and view all the answers

    Which airway technique is contraindicated in patients with a known or suspected cervical spine fracture?

    <p>Head tilt</p> Signup and view all the answers

    What complication may arise from using a nasopharyngeal airway?

    <p>Injury to nasal mucosa causing bleeding</p> Signup and view all the answers

    What is the primary purpose of an oropharyngeal airway?

    <p>To prevent the tongue from obstructing the airway</p> Signup and view all the answers

    Which of the following is NOT an indication for tracheal intubation?

    <p>Controlled ventilation in obese patients</p> Signup and view all the answers

    What is a common complication associated with oropharyngeal airway use?

    <p>Epiglottic obstruction</p> Signup and view all the answers

    Which technique is an advanced airway management method?

    <p>Cricothyroidotomy</p> Signup and view all the answers

    What is one of the primary concerns when using a nasopharyngeal airway?

    <p>Entry of the tube into the esophagus</p> Signup and view all the answers

    What is the maximum dose of lidocaine when used with epinephrine for a patient based on lean body weight?

    <p>7 mg/kg</p> Signup and view all the answers

    What is a critical feature of the patency of airway assessment?

    <p>Facial bone integrity</p> Signup and view all the answers

    Which of the following local anesthetics has the highest maximum dose per kg of body weight?

    <p>Chlorprocaine</p> Signup and view all the answers

    Which of the following is NOT a symptom of systemic toxicity from local anesthetics?

    <p>Hypertension</p> Signup and view all the answers

    What is the order of CNS effects typically observed with local anesthetic systemic toxicity?

    <p>Numbness of tongue, disorientation, respiratory arrest</p> Signup and view all the answers

    Which condition could lead to systemic toxicity from local anesthetics?

    <p>Accidental intravascular injection</p> Signup and view all the answers

    What is the main purpose of administering atropine or glycopyrrolate during anesthesia?

    <p>To block muscarinic receptors and reduce cholinergic side effects</p> Signup and view all the answers

    Which of the following statements accurately describes regional anesthesia?

    <p>No CNS depression occurs unless there is an overdose of local anesthetic</p> Signup and view all the answers

    What should be considered a contraindication to regional anesthesia?

    <p>Coagulopathy</p> Signup and view all the answers

    During preparation for regional anesthesia, what is an important step to ensure effectiveness?

    <p>Use anatomical landmarks for nerve localization</p> Signup and view all the answers

    What is the primary purpose of premedication in the context of anesthesia?

    <p>To provide sedation, amnesia, and relieve anxiety and pain</p> Signup and view all the answers

    Which of the following is a potential complication of regional anesthesia?

    <p>Peripheral neuropathy from intraneural injection</p> Signup and view all the answers

    What is a notable characteristic of thiopental as an intravenous anesthetic?

    <p>It is rapidly redistributed, resulting in a short-lived effect</p> Signup and view all the answers

    What type of regional anesthesia involves the application of a local anesthetic around a peripheral nerve?

    <p>Peripheral nerve blockades</p> Signup and view all the answers

    Which of the following effects is NOT associated with thiopental?

    <p>Increased cerebral metabolism</p> Signup and view all the answers

    Which factor is NOT a relative indication for using regional anesthesia?

    <p>Patient's inability to cooperate</p> Signup and view all the answers

    What technique is used in regional anesthesia for proper needle placement?

    <p>Guided use of paresthesias and peripheral nerve stimulation</p> Signup and view all the answers

    Why is it important to prevent parasympathomimetic effects during anesthesia?

    <p>To avoid complications like excessive salivation and bronchial secretions</p> Signup and view all the answers

    What type of solution is thiopental prepared as?

    <p>A pale yellow 2.5% solution with pH 10.5</p> Signup and view all the answers

    What can be a consequence of administering a bolus dose of thiopental?

    <p>Respiratory depression and apnea</p> Signup and view all the answers

    Which condition is a contraindication for the use of thiopental?

    <p>Untreated hypovolemia or hypotension</p> Signup and view all the answers

    What is the typical half-life of thiopental?

    <p>5 to 12 hours</p> Signup and view all the answers

    What is the most common mild reaction to blood transfusions?

    <p>Febrile reaction</p> Signup and view all the answers

    Which symptom is less commonly associated with a febrile reaction during a transfusion?

    <p>Urticaria</p> Signup and view all the answers

    What management step should be taken in the event of a mild allergic reaction to a transfusion?

    <p>Slow the transfusion rate and give IV antihistamines</p> Signup and view all the answers

    Which factor increases the likelihood of experiencing a febrile reaction during transfusions?

    <p>Previous exposure to the donor's blood</p> Signup and view all the answers

    What is a potential management strategy for severe allergic reactions during transfusions?

    <p>Administer subcutaneous epinephrine and hydrocortisone</p> Signup and view all the answers

    What is the most common complication associated with regional anesthesia during labor?

    <p>Hypotension due to sympathectomy</p> Signup and view all the answers

    Which of the following is a method of pain relief during labor that involves controlled breathing techniques?

    <p>Psychoprophylaxis</p> Signup and view all the answers

    What type of anesthesia is typically preferred for cesarean sections?

    <p>Regional anesthesia</p> Signup and view all the answers

    What common drugs are associated with systemic medication for pain relief during labor?

    <p>Opioids, tranquilizers, ketamine</p> Signup and view all the answers

    Which route of analgesia is known for providing excellent analgesia with minimal depressant effects on both mother and fetus?

    <p>Regional anesthesia</p> Signup and view all the answers

    What is a primary reason for the popularity of propofol in outpatient surgery?

    <p>It reduces post-anesthesia recovery time.</p> Signup and view all the answers

    Which characteristic differentiates benzodiazepines from propofol in their use as anesthetic agents?

    <p>Benzodiazepines can be used for premedication as well as induction.</p> Signup and view all the answers

    What is a key metabolic advantage of propofol compared to thiopental?

    <p>Propofol undergoes a more rapid rate of liver metabolism.</p> Signup and view all the answers

    Which of the following is a notable feature of flumazenil, the benzodiazepine antagonist?

    <p>It works through competitive inhibition.</p> Signup and view all the answers

    What differentiates the use of neuroleptics in anesthesia from other classes of drugs?

    <p>They are mainly used for antiemetic properties.</p> Signup and view all the answers

    Which type of anesthesia involves the administration of anesthetics near a nerve to block sensation?

    <p>Regional Anesthesia</p> Signup and view all the answers

    What is the role of fluid therapy in anesthesia management?

    <p>To maintain fluid balance</p> Signup and view all the answers

    Which method is primarily used to maintain adequate oxygenation during anesthesia?

    <p>Manual Ventilation</p> Signup and view all the answers

    What is a potential risk associated with the use of epidural anesthesia?

    <p>Hematoma formation</p> Signup and view all the answers

    Which condition requires careful management during anesthesia due to its potential complications?

    <p>Malignant Hyperthermia</p> Signup and view all the answers

    How does local infiltration anesthesia differ from regional anesthesia?

    <p>It provides anesthesia for specific, localized areas.</p> Signup and view all the answers

    Which factor is critical for preoperative assessment before administering anesthesia?

    <p>ASA Classification</p> Signup and view all the answers

    What is the purpose of supplemental oxygen in anesthesia?

    <p>To prevent hypoxemia during surgery</p> Signup and view all the answers

    Which factor is least likely to influence the degree of pain experienced by a patient?

    <p>Type of clothing worn</p> Signup and view all the answers

    What is the primary advantage of preemptive analgesia?

    <p>It reduces the potency of peripheral and central pain mechanisms.</p> Signup and view all the answers

    What is a key requirement for a patient to effectively use Patient Controlled Analgesia (PCA)?

    <p>Patient must be fully conscious and capable of understanding instructions.</p> Signup and view all the answers

    Which monitoring device is crucial for assessing physiological function during anesthesia?

    <p>Capnometer</p> Signup and view all the answers

    What is a limitation of using a pulse oximeter for monitoring patients?

    <p>It can provide inaccurate readings in certain physiological conditions.</p> Signup and view all the answers

    Why is it important to monitor the exposed parts of a patient during anesthesia?

    <p>To monitor physiological signs that could indicate distress.</p> Signup and view all the answers

    What common misconception about monitoring devices is incorrect?

    <p>All devices are 100% accurate.</p> Signup and view all the answers

    Which of the following routes of analgesic administration is not typically used?

    <p>Inhalation with local anesthetics</p> Signup and view all the answers

    Which condition is most likely to lead to extrarenal sodium loss?

    <p>Vomiting</p> Signup and view all the answers

    What symptom is characteristic of 10% body water loss?

    <p>Oliguria</p> Signup and view all the answers

    Which factor can cause redistribution of extracellular fluid volume?

    <p>Severe burns</p> Signup and view all the answers

    What is a potential risk when correcting chronic hyponatremia too quickly?

    <p>Central pontine myelinolysis</p> Signup and view all the answers

    Which condition is associated with renal loss of water?

    <p>Diabetes insipidus</p> Signup and view all the answers

    What is one of the most common mild reactions during blood transfusions?

    <p>Febrile reactions</p> Signup and view all the answers

    What is a common symptom experienced during a febrile reaction?

    <p>Facial flushing</p> Signup and view all the answers

    What management step should be taken for a patient experiencing a mild allergic reaction during transfusion?

    <p>Slow transfusion rate and give IV antihistamines</p> Signup and view all the answers

    What is a notable characteristic of severe reactions to blood transfusion?

    <p>Can lead to leukocyte depletion in future transfusions</p> Signup and view all the answers

    What is the recommended action if a febrile reaction occurs with a temperature above 38ºC?

    <p>Stop transfusion and administer antipyretics</p> Signup and view all the answers

    What is the primary goal in preparing a patient for emergency surgery when optimization of non-surgical disease states is not feasible?

    <p>To optimize what is possible in the time available</p> Signup and view all the answers

    When can a patient be transported to the post-anesthesia care unit (PACU)?

    <p>After ABCs are stable</p> Signup and view all the answers

    Which of the following is a potential complication related to the central nervous system during postoperative management?

    <p>Agitation</p> Signup and view all the answers

    Which complication is associated with the respiratory system during postoperative management?

    <p>Upper airway obstruction</p> Signup and view all the answers

    What is an expected outcome for a patient before being discharged from the post-anesthesia care unit?

    <p>Stabilization of circulation and ventilation</p> Signup and view all the answers

    What is the primary purpose of simultaneous administration of atropine or glycopyrrolate during regional anesthesia?

    <p>To decrease cholinergic side effects</p> Signup and view all the answers

    Which of the following statements accurately describes regional anesthesia?

    <p>It involves local anesthetic application to reduce nerve impulse transmission.</p> Signup and view all the answers

    Which complication is NOT typically associated with regional anesthesia?

    <p>Unconsciousness due to overdose</p> Signup and view all the answers

    What should be done before administering regional anesthesia to a patient?

    <p>Ensure thorough pre-op evaluation and patient consent</p> Signup and view all the answers

    Which of the following is a relative contraindication for regional anesthesia?

    <p>Inability to cooperate during procedure</p> Signup and view all the answers

    Which preoperative optimization is considered crucial for patients with diabetes mellitus?

    <p>Optimize glycemic control</p> Signup and view all the answers

    How can nerve localization be effectively achieved in regional anesthesia?

    <p>Using anatomical landmarks and paresthesias</p> Signup and view all the answers

    Which of the following indicates a successful regional anesthesia technique?

    <p>Absence of pain in the targeted area</p> Signup and view all the answers

    What is the primary purpose of assessing a patient's airway during the physical examination?

    <p>To evaluate the likelihood of difficult intubation</p> Signup and view all the answers

    What is the potential risk if local anesthetic is injected intravascularly during a regional anesthesia procedure?

    <p>Hypotension and bradycardia</p> Signup and view all the answers

    Which classification helps in assessing the visibility of the airway during intubation?

    <p>Mallampati classification</p> Signup and view all the answers

    Which of the following conditions could lead to increased risk during anesthesia related to respiratory status?

    <p>Chronic obstructive pulmonary disease (COPD)</p> Signup and view all the answers

    What should be assessed regarding a patient's medical history to help identify potential drug reactions?

    <p>Family history of anesthetic complications</p> Signup and view all the answers

    Which physical examination finding would be most relevant in assessing for difficult intubation?

    <p>Mouth opening</p> Signup and view all the answers

    What is the significance of the 'thyromental distance' in airway assessment?

    <p>Predicts the ease of securing the airway</p> Signup and view all the answers

    In which scenario is monitoring for raised intracranial pressure particularly relevant?

    <p>In patients with a history of seizures</p> Signup and view all the answers

    How does smoking cessation impact postoperative outcomes?

    <p>It decreases the risk of respiratory complications</p> Signup and view all the answers

    Which drug class is essential to optimize before surgery to minimize complications in patients with DM?

    <p>Oral hypoglycemics</p> Signup and view all the answers

    What is the maximum dose of bupivacaine without epinephrine for use in anesthetic procedures?

    <p>2.5 mg/kg</p> Signup and view all the answers

    Which symptom is likely to occur first during systemic toxicity of local anesthetics at the CNS level?

    <p>Numbness of the tongue</p> Signup and view all the answers

    What factor is primarily associated with the risk of systemic toxicity of local anesthetics?

    <p>Accidental intravascular injection</p> Signup and view all the answers

    Which of the following statements regarding the maximum doses of local anesthetics is accurate?

    <p>Chlorprocaine can be used in higher doses than bupivacaine.</p> Signup and view all the answers

    What is a potential consequence of systemic toxicity affecting the cardiovascular system?

    <p>Hypotension</p> Signup and view all the answers

    What is the approximate total body water (TBW) in liters for a 70 kg adult?

    <p>42 L</p> Signup and view all the answers

    Which of the following accurately describes the fluid distribution in a 70 kg adult?

    <p>ICF contains more than ECF</p> Signup and view all the answers

    What clinical signs are indicative of ECF volume deficit?

    <p>Dry mucous membranes and decreased skin turgor</p> Signup and view all the answers

    If a facial mask with an oxygen reservoir is set at 8 L/min, approximately what percentage of oxygen concentration is delivered?

    <p>60%</p> Signup and view all the answers

    How does the Venturi mask benefit oxygen delivery?

    <p>Allows for consistent and predictable FIO2</p> Signup and view all the answers

    Which of the following fluid loss categorizations corresponds to a TBW fluid loss of more than 10%?

    <p>Severe dehydration</p> Signup and view all the answers

    What happens to hematocrit levels during extracellular fluid expansion?

    <p>Hematocrit decreases</p> Signup and view all the answers

    What essential factor must be ensured prior to anesthesia concerning hydration?

    <p>Adequate hydration must be maintained</p> Signup and view all the answers

    What are common symptoms of anaphylactic reactions in IgA deficient patients?

    <p>Apprehension and urticarial eruptions</p> Signup and view all the answers

    What is the typical time frame for the onset of TRALI after blood transfusion?

    <p>2-4 hours post transfusion</p> Signup and view all the answers

    What is a major characteristic of the immunologic cause of TRALI?

    <p>It triggers an acute pulmonary reaction</p> Signup and view all the answers

    What management strategies are recommended for anaphylactic reactions in IgA deficient patients?

    <p>Providing circulatory support and bronchodilators</p> Signup and view all the answers

    What is a primary consideration when planning future transfusions for an IgA deficient patient?

    <p>Ensuring blood is free of IgA antigens</p> Signup and view all the answers

    What is a common outcome of perioperative transfusions in relation to immune response?

    <p>Association with earlier cancer recurrence</p> Signup and view all the answers

    Which signs are indicative of the most serious hemolytic transfusion reactions?

    <p>Donor incompatibility with recipient's blood</p> Signup and view all the answers

    What nature does TRALI primarily exhibit as a pulmonary condition?

    <p>Noncardiogenic pulmonary edema</p> Signup and view all the answers

    Which treatment is typically employed for TRALI management?

    <p>Oxygen therapy and mechanical ventilation</p> Signup and view all the answers

    What is a significant indicator of septic shock in a patient?

    <p>Warm skin with fever</p> Signup and view all the answers

    Which complication can result from hypovolemic shock?

    <p>Cardiac ischemia</p> Signup and view all the answers

    Which electrolyte change is most notably associated with stored blood?

    <p>Increased potassium levels</p> Signup and view all the answers

    What is the correct first step in treating shock?

    <p>Provide oxygen</p> Signup and view all the answers

    In spinal shock, what physiological state is typically observed?

    <p>Decreased sympathetic tone and warm skin</p> Signup and view all the answers

    Which type of shock is most commonly associated with bacterial infections?

    <p>Septic shock</p> Signup and view all the answers

    What is an atypical feature of septic shock?

    <p>Hypothermia</p> Signup and view all the answers

    Which of the following is NOT a step in the general management of shock?

    <p>Monitoring blood coagulation</p> Signup and view all the answers

    Which of these correctly describes a feature of obstructive shock?

    <p>Resulting from impaired venous return</p> Signup and view all the answers

    Which intervention is considered part of the initial treatment for septic shock?

    <p>Antibiotics and volume expansion</p> Signup and view all the answers

    Which of the following factors is most critical in optimizing medical treatment preoperatively to reduce complications?

    <p>Smoking cessation</p> Signup and view all the answers

    In the context of airway assessment, which classification allows for the estimation of intubation difficulty based on visibility?

    <p>Mallampati classification</p> Signup and view all the answers

    What aspect of a patient's history is most critical in predicting anesthetic complications?

    <p>Previous anesthetic experience and complications</p> Signup and view all the answers

    Which respiratory condition requires optimization to reduce operative risks and improve postoperative outcomes?

    <p>Chronic Obstructive Pulmonary Disease (COPD)</p> Signup and view all the answers

    Which condition is NOT included in the focused review of systems that might influence anesthesia management?

    <p>Osteoporosis</p> Signup and view all the answers

    In assessing a patient's nutritional status preoperatively, which of the following conditions is prioritized for correction?

    <p>Malnourished states</p> Signup and view all the answers

    Which physical examination finding is MOST indicative of possible difficult intubation?

    <p>Limited jaw opening</p> Signup and view all the answers

    Which preoperative intervention is recommended for patients diagnosed with diabetes mellitus?

    <p>Optimizing glycemic control</p> Signup and view all the answers

    Which airway anatomical feature, when assessed, would be least likely to indicate potential intubation difficulties?

    <p>Nasal passage patency</p> Signup and view all the answers

    Which type of medication is most associated with increasing the risk of perioperative bleeding?

    <p>Anticoagulants</p> Signup and view all the answers

    Study Notes

    Pain Control

    • Pain relief is crucial for proper recovery and minimizing complications.
    • Preoperative visits can significantly benefit patients by addressing concerns and preparing them for surgery.
    • Unrelieved pain can lead to numerous postoperative complications.
    • Individual pain perception is influenced by factors like age, personality, premedication, surgical site, and anesthetic technique.
    • Various administration routes are available, including IV, IM, oral, epidural, and rectal.
    • Preemptive analgesia aims to prevent pain by reducing noxious stimuli and minimizing the need for higher doses of analgesics post-surgery.
    • Patient-controlled analgesia (PCA) empowers patients to administer small doses of opioids for self-management of pain.
    • PCA requires patients to be alert, and it involves setting specific bolus doses and lockout periods to avoid overuse.

    Monitoring

    • Monitoring is essential for patient safety and assessing physiological changes during surgery.
    • While monitors with alarms enhance safety, they do not substitute for the anesthetist's vigilance.
    • Physical examination combined with monitoring ensures optimal patient care.
    • Basic monitoring includes blood pressure cuff, ECG, pulse oximeter, stethoscope, temperature probe, and capnometer (if intubated).
    • Monitoring equipment and strategies vary based on surgery type, duration, location, and the patient's pre-existing conditions.

    Pulse Oximeter

    • Non-invasive device that measures oxygen saturation (SaO2) by detecting light absorption by hemoglobin.
    • It provides valuable information about oxygenation status, especially during general anesthesia.
    • It can display pulse waveforms for further analysis.
    • Inaccurate readings can occur due to hypotension, vasoconstriction, dyes, nail polish, other hemoglobin types, limb compression, and movement.

    Capnometer

    • Measures exhaled carbon dioxide (CO2) to assess lung ventilation and cardiac output.
    • It confirms endotracheal tube placement.

    ECG

    • Monitors heart rate, rhythm, and potential changes like ST segment elevation or depression, indicating cardiac abnormalities.

    Other Commonly Used Devices

    • Blood pressure cuff (manual or automatic)
    • Stethoscope (precordial, esophageal)
    • Thermometer (surface or core)
    • Peripheral nerve stimulators (for monitoring neuromuscular blockade)
    • Machine function monitors (volume, pressure, inspired oxygen alarms)
    • Mass spectrometer/gas analyzer (identifies and measures inhaled/exhaled gases)

    Less Frequently Used Monitors

    • Urinary catheter and urometer
    • Central venous line (for rapid fluid infusion, vasoactive drug delivery, and CVP measurement)
    • Arterial line (for continuous blood pressure monitoring and frequent ABG sampling)
    • Swan-Ganz catheter (measures CVP, PCWP, pulmonary artery pressures, cardiac output, mixed venous blood gases, and core temperature)
    • Intracranial pressure (ICP) monitoring
    • Electroencephalogram (EEG), brain and spinal cord evoked potentials
    • Transcutaneous gas measurements
    • Transesophageal echocardiography (TEE)

    General Anesthetic Agents

    • General anesthesia (GA) involves delivering anesthetic drugs (inhaled or infused) to achieve a desired state of central nervous system (CNS) depression.
    • The "6 A's" of anesthesia encompass: anesthesia (loss of consciousness), analgesia (pain control), amnesia (loss of recall), areflexia (muscle relaxation), autonomic areflexia (decreased sympathetic nervous system function), and antiemetic (nausea and vomiting prevention).

    Opioids

    • Opioids are medications that bind to opioid receptors (also known as morphine receptors) in the brain and spinal cord, resulting in various effects.
    • Opioid receptors play roles in pain perception, mood modulation, and respiratory depression.
    • Commonly used for pre-, intra-, and postoperative analgesia, and as induction agents.
    • They reduce the minimum alveolar concentration (MAC) required for volatile anesthetics.

    Morphine

    • Prototype opioid with numerous effects, primarily impacting the central nervous system (CNS) and various organ systems.
    • CNS effects include analgesia, mood changes, sedation, respiratory depression, and decreased cough reflex.
    • Other effects include vasodilatation, orthostatic hypotension, bronchial constriction, constipation, biliary colic, urinary retention, and histamine release.

    Volatile Inhalational Agents

    • Inhaled anesthetics are volatile liquids that vaporize at room temperature and enter the bloodstream through the lungs.
    • They provide a rapid, reversible effect and are routinely used for inducing and maintaining anesthesia.
    • Important considerations include their MAC values, which are essential for determining the required anesthetic depth.
    • Commonly used agents include halothane, enflurane, isoflurane, sevoflurane, and nitrous oxide.

    Complications of General Anesthesia

    • Malignant hyperthermia (MH) is a rare but potentially fatal reaction to certain anesthetic agents, usually triggered by succinylcholine (SCh) or inhalational agents.
    • MH presents with hyperthermia, muscle rigidity, tachycardia, tachypnea, and metabolic acidosis.
    • Prevention involves careful patient history, avoiding triggering agents, and utilizing alternative medications.
    • Management includes rapid discontinuation of triggering medications, hyperventilation with 100% oxygen, administration of dantrolene (muscle relaxant), and supportive care.

    Myocardial Infarction (MI)

    • Elective surgeries are generally postponed for 6 months after an MI to minimize the risk of reinfarction or death.
    • Perioperative MI carries a high mortality rate.
    • Invasive monitoring and intensive care unit (ICU) management can reduce this risk.

    Respiratory Diseases

    • Pulmonary disease can complicate ventilation and the delivery of volatile anesthetics, requiring careful pre-operative optimization and close intra- and postoperative monitoring.

    Aspiration Syndrome

    • The severity of gastric aspiration depends on the volume, acidity, and contamination of the aspirate, as well as the patient's health status.
    • Avoiding reflex inhibition, reducing gastric volume and acidity, and employing rapid sequence induction can help prevent aspiration.

    Airway Management

    • Most acute airway problems in an unconscious patient can be managed with:
      • 100% O2 with the patient in the lateral position (contraindicated in known suspected C-spine fracture)
      • head tilt via extension at the atlanto-occipital joint (contraindicated in known/suspected C-spine fracture)
      • jaw thrust via subluxation of temporomandibular joint (TMJ)
      • suctioning (secretions, vomitus, foreign body)
      • positioning to prevent aspiration
      • inserting oro- or naso-pharyngeal airway
    • Nasopharyngeal airway is indicated if an oropharyngeal airway is difficult (e.g. trismus, mouth trauma):
      • large adult 8-9 mm, medium adult 7-8 mm, small adult 6-7 mm internal diameter
      • complications include tube too long (esophagus), laryngospasm, vomiting, nasal mucosa injury and bleeding
    • Oropharyngeal airway holds tongue away from the posterior wall of the pharynx:
      • large adult 100 mm, medium adult 90 mm, small adult 80 mm
      • facilitates suctioning of pharynx
      • prevents patient from biting and occluding endotracheal tube (ETT)
      • complications include tube too long (epiglottis vs. larynx obstruction), improper insertion (posterior tongue push)
    • More advanced airway techniques include tracheal intubation (orally or nasally), cricothyroidotomy, tracheostomy.

    Tracheal Intubation

    • Definition: Insertion of a tube into the trachea either orally or nasally

    Indications for Intubation - the 5 Ps

    • Patency of airway required:
      • decreased level of consciousness (LOC)
      • facial injuries
      • epiglottitis
      • laryngeal edema (e.g. burns, anaphylaxis)
    • Protect the lungs from aspiration:
      • absent protective reflexes (e.g. IV fluids)

    IV Anesthetics (Excluding Opioids)

    • IV administration provides rapid onset of effects:
      • given as a bolus or continuous infusion, titrated to effect
    • Common agents used for induction:
      • Thiopental (Sodium Thiopental, Sodium Thiopentone, STP)
        • ultrashort-acting thiobarbiturate
        • most commonly used as an induction agent
        • prepared as a pale yellow 2.5% solution with pH 10.5 (alkaline)
        • rapid distribution to vessel rich organs (brain, liver, heart, kidney) leading to unconsciousness in 30 seconds
        • rapid redistribution from vessel rich tissues to muscle and fat causes short lived effect (5 minutes)
        • slow metabolism and elimination (T1/2 =5-12 hrs), resulting in residual sedation for hours
        • effects include unconsciousness, decreased cerebral metabolism and O2 requirements, reduction of cerebral blood flow, decrease in CO, BP, reflex tachycardia, respiratory depression (apnea with bolus dose).
        • no analgesic properties, may actually increase subjective feeling of pain (anti-analgesia)
        • no muscle relaxant properties
        • contraindications: lack of intubation and resuscitation equipment, potential difficult intubation, hypersensitivity, untreated hypovolemia, hypotension, shock-like states, cardiac failure, porphyria

    Regional Anesthesia

    • Definition: Local anesthetic applied around a peripheral nerve at any point for the purposes of reducing or preventing impulse transmission
    • No CNS depression (unless overdose of local anesthetic); patient conscious
    • Techniques include epidural and spinal anesthesia, peripheral nerve blockades, IV regional anesthesia

    Preparation for Regional Anesthesia

    • Patient Preparation:
      • thorough pre-op evaluation and assessment of patient
      • technique explained to patient
      • IV sedation may be indicated before block
      • monitoring should be as extensive as for general anesthesia
    • Nerve Localization:
      • anatomical landmarks, local anatomy (e.g. iliac crests line crosses L3-L4 interspace, axillary artery guides brachial plexus)
      • paresthesias and peripheral nerve stimulation used as a guide to proper needle placement

    Relative Indications for Regional Anesthesia

    • Avoidance of dangers of general anesthesia (e.g. difficult intubation, severe respiratory failure)
    • Patient specifically requests regional anesthesia
    • For high quality post-op pain relief
    • General anesthesia not available

    Contraindications to Regional Anesthesia

    • Allergy to local anesthetic
    • Patient refusal, lack of cooperation
    • Lack of resuscitation equipment
    • Lack of IV access
    • Coagulopathy
    • Certain types of preexisting neurological dysfunction
    • Local infection at block site

    Complications of Regional Anesthesia

    • Failure of technique
    • Systemic drug toxicity due to overdose or intravascular injection
    • Peripheral neuropathy due to intraneural injection
    • Pain or hematoma at injection site
    • Infection

    Nerve Fibres

    • Different types categorized as follows:
      • Sensory blockade with relative preservation of motor function (for pain management)
      • Motor blockade with relative preservation of sensory function (for surgery)
      • Complete blockade (both sensory and motor)
      • potential for toxicity

    Maximum Doses for Local Anesthetics (LA)

    • Always be aware of the maximum dose for the particular LA used
    • Maximum dose usually expressed as (mg of LA) per (kg of lean body weight) and as a total maximal dose (adjusted for young/elderly/ill)
    • Lidocaine maximum dose: 5 mg/kg (with epinephrine: 7mg/kg)
    • Chlorprocaine maximum dose: 11 mg/kg (with epinephrine: 14 mg/kg)
    • Bupivacaine maximum dose: 2.5 mg/kg (with epinephrine: 3 mg/kg)

    Systemic Toxicity

    • Occurs by accidental intravascular injection, LA overdose, or unexpectedly rapid absorption
    • Systemic toxicity manifests mainly at CNS and CVS
    • CNS effects first appear excitatory due to initial block of inhibitory fibres; subsequently, block of excitatory fibres
    • CNS effects (in approximate order of appearance):
      • numbness of tongue, perioral tingling
      • disorientation, drowsiness
      • tinnitus
      • visual disturbances
      • muscle twitching, tremors
      • convulsions, seizures
      • generalized CNS depression, coma, respiratory arrest

    Transfusion reactions

    • Febrile - most common mild reaction (0.5% - 4%).
    • Due to alloantibodies to WBC, platelet, or other donor plasma antigens
    • Fever likely caused by pyrogens liberated from lysed cells
    • More common if previous transfusion
    • Mild fever < 38° with or without rigors, fever may be > 38° with restlessness and shivering
    • Nausea, facial flushing, headache, myalgias; hypotension, chest and back pain (less common)
    • Occurs near completion of transfusion or within 2 hours
    • Up to 40% with mild reactions will not experience another reaction with future transfusions
    • With severe/recurrent reactions, future transfusions may cause leukocyte depletion

    Allergic

    • Occurs in about 3% of transfusions
    • Due to IgE alloantibodies vs. substances in donor plasma
    • Mast cells activated with histamine release
    • Usually occurs in pre-exposed e.g. multiple transfusions, multiparous
    • Often have history of similar reactions
    • Abrupt onset pruritic erythema/urticaria on arms and trunk, occasionally with fever
    • Less common - involvement of face, larynx, and bronchioles

    Pain Control

    • Goal is to provide pain relief safely with minimal disturbance of homeostasis
    • Unrelieved pain can be the cause of many postoperative complications
    • Factors influencing the degree of pain include age, personality, premedication, surgical site, and anesthetic technique
    • Routes - IV, IM, oral, epidural, rectal
    • Preemptive analgesia
      • Prevent/reduce noxious stimuli which potentiate peripheral and central pain mechanisms
      • In postoperative period the dose of analgesic is decreased and the side effects are less frequent
      • Use - NSAID's, opioids, local anesthetics, combined agents
    • PCA (patient controlled analgesia)
      • Self-administration of small doses of opiates via pump
      • Bolus dose is preset
      • Lockout period is set to limit frequency of self-administration
      • Requirements - oriented patient, IV, SC, or epidural access

    Monitoring

    • Provides information that improves the safety of anesthesia and provides a means to assess physiological function
    • Appropriate monitors with alarms are intended to enhance but not replace the vigilance of the anesthetist
    • Physical examination, observation, assessment, and diagnosis remain the most important tools available to the anesthetist
    • Routine monitors for all cases: BP cuff, ECG, O2 sat monitor, stethoscope, temperature probe, exposed part of patient visible, capnometer if intubated
    • Organ systems monitored and other devices used to monitor will vary depending on the nature, length, location, and systems involved in the surgery, and patient’s pre-existing condition/diseases

    Pulse Oximeter

    • Measures SaO2 by red and infrared light absorption by Hb; oxygenated and deoxygenated Hb have different absorption characteristics
    • Non-invasive
    • Can show pulse waveforms on suitably equipped monitors
    • If ventilation is accidentally terminated, the SaO2 may remain normal for several minutes in a well oxygenated patient due to the high partial pressure of O2 remaining in the lungs
    • Inaccurate with hypotension, vasoconstriction, dyes
    • Propofol (Diprivan)
      • Unique agent in its own class (an alkyl phenol)
      • Used for induction and/or maintenance of anesthesia
      • Thick white soybean-based solution
      • Pharmacological effects similar to that of thiopental; thus similar contraindications but is safe for porphyria patients
      • Metabolism and elimination much more rapid due to increased rate of liver metabolism compared to thiopental
      • Less residual sedative effect, patient recovers sooner (T1/2 = 0.9 hr), thus popular for out patient surgery since reduces post-anesthesia recovery time; decreased incidence of nausea and vomiting
      • More suited for continuous infusion than STP due to rapid elimination
      • More expensive

    Benzodiazepines

    • Also known as the minor tranquilizers
    • Used as a premedication prior to induction or as an induction agent in combination with other drugs
    • Oral and injectable formulations available
    • Act on specific brain (GABA) receptors to produce selective anti-anxiety and sedative effects; in correct doses, causes only slight depression of CVS and respiratory systems
    • Onset less than 5 minutes if given IV
    • Duration of action long but variable/somewhat unpredictable
    • Benzodiazepine antagonist flumazenil (Anexate)
      • Competitive inhibition
      • Does not affect benzodiazepine metabolism, therefore once effects of reversal wear off, sedation may return

    Neuroleptics

    • Also known as the major tranquilizers, rarely used in anesthesia
    • Blockade of dopamine receptors at various locations in CNS
    • Droperidol used in low dose as antiemetic

    Narcotics/Opioids

    • Opium: natural product derived from poppy plant extract
    • Opiates: derived from opium

    Regional Anesthesia

    • Definition of regional anesthesia
    • Preparation of regional anesthesia
    • Nerve Fibres
    • Epidural and Spinal Anesthesia
    • IV Regional Anesthesia
    • Peripheral Nerve Blocks
    • Obstetrical Anesthesia

    Local Infiltration, Hematoma Blocks

    • Relatively safe – avoid intraneural injection and neurotoxic agents

    Local Anesthetics

    • Provides good operating conditions

    Obstetrical Anesthesia

    • All patients entering the delivery room potentially require anesthesia, whether planned or as an emergency
    • Adequate anesthesia of obstetric patients requires a clear understanding of maternal and fetal physiology
    • Options for pain relief during parturition (labour) are
      • Psychoprophylaxis – Lamaze method
        • Patterns of breathing and focused attention of fixed object
      • Systemic medication
        • Easy to administer but risk of maternal or neonatal depression
        • Common drugs: opioids, tranquilizers, ketamine
      • Regional anesthesia
        • Provides excellent analgesia with minimal depressant effects in mother and fetus
        • Hypotension as a consequence of sympathectomy is the most common complication
        • Maternal BP monitored q2-5 min for 15-20 min after initiation and regularly thereafter
        • Techniques used: epidural, combined spinal epidural, pudendal blocks, spinal, paracervical, lumbar sympathetic blocks
      • Inhalational analgesia
        • Easy to administer, makes uterine contractions more tolerable, but does not relieve pain completely
        • 50% nitrous oxide
    • Anesthesia for cesarean section
      • Regional - spinal or epidural

    Extrarenal Na+ Loss

    • Gastrointestinal causes: vomiting, nasogastric suction, drainage, fistulae, diarrhea
    • Skin/Respiratory causes: insensible losses (fever), sweating, burns
    • Vascular causes: hemorrhage

    Renal Na+ and H2O Loss

    • Diuretics
    • Osmotic diuresis
    • Hypoaldosteronism
    • Salt-wasting nephropathies

    Renal H2O Loss

    • Diabetes insipidus (central or nephrogenic)

    Hypovolemia with Normal or Expanded ECF Volume

    • Decreased cardiac output (CO)
    • Redistribution: hypoalbuminemia (cirrhosis, nephrotic syndrome), capillary leaking (acute pancreatitis, rhabdomyolysis, ischemic bowel)

    Management of Dehydration

    • Replace water and electrolytes based on patient needs
    • With chronic hyponatremia, correction should be over >48 hours to avoid CNS central pontine myelinolysis

    Signs and Symptoms of Dehydration

    • Mild (5% loss): decreased skin turgor, sunken eyes, dry mucous membranes, dry tongue, reduced sweating
    • Moderate (10% loss): oliguria, orthostatic hypotension, tachycardia, low volume pulse, cool peripheries, reduced filling of peripheral veins and central venous pressure (CVP), hemoconcentration, apathy
    • Severe (15% loss): profound oliguria and compromised CNS function with or without altered sensorium

    Febrile Reaction to Transfusion

    • Most common mild reaction, 0.5%-4% of transfusions
    • Due to alloantibodies to WBC, platelet, or other donor plasma antigens
    • Fever likely caused by pyrogens liberated from lysed cells
    • More common if previous transfusion
    • Mild fever < 38° with or without rigors, fever may be > 38° with restlessness and shivering
    • Nausea, facial flushing, headache, myalgias; hypotension, chest and back pain (less common)
    • Near completion of transfusion or within 2 hours
    • Up to 40% with mild reactions will not experience another reaction with future transfusions
    • With severe/recurrent reactions, future transfusions may cause leukocyte depletion

    Management of Febrile Reaction to Transfusion

    • Rule out fever due to hemolytic reaction or bacterial contamination
    • Mild < 38°: decrease infusion rate and antipyretics
    • Severe: stop transfusion, antipyretics, antihistamines, symptomatic treatment

    Allergic Reaction to Transfusion

    • Mild allergic reaction occurs in about 3% of transfusions
    • Due to IgE alloantibodies vs substances in donor plasma
    • Mast cells activated with histamine release
    • Usually occurs in pre-exposed individuals (e.g., multiple transfusions, multiparous)
    • Often have history of similar reactions
    • Abrupt onset pruritic erythema/urticaria on arms and trunk, occasionally with fever
    • Less common: involvement of face, larynx, and bronchioles

    Management of Allergic Reaction to Transfusion

    • Mild: slow transfusion rate, IV antihistamines
    • Moderate to severe: stop transfusion, IV antihistamines, subcutaneous epinephrine, hydrocortisone, IV fluids, bronchodilators
    • Prophylactic: antihistamines 15-60 minutes prior to transfusion, washed or deglycerolized frozen RBC

    Preoperative Optimization

    • Diuretics, oral hypoglycemics, anticoagulants, steroids, monamine oxidase inhibitors (MAOI), and drugs with CNS side effects
    • Optimization of medical treatment preoperatively will reduce peri- and postoperative complications
      • Diabetes mellitus (DM): optimize glycemic control
      • Nutritional status: correct malnourished states
      • Smoking: encourage cessation
      • Obesity: encourage weight loss
      • Chronic obstructive pulmonary disease (COPD): optimize respiratory status, teach postoperative exercises (e.g., incentive spirometry)

    Anesthesia History

    • Previous anesthetic experience and complications, previous intubations, medications drug allergies, and allergies to topical preparations
    • Focused review of systems
      • CNS: seizures, transient ischemic attack (TIA), cerebrovascular accident (CVA), raised intracranial pressure (ICP), spinal disease, arteriovenous malformation (AVM)/aneurysm, neuromuscular disease
      • Resp: smoker, asthma, COPD, upper respiratory tract infection (URTI), dyspnea, stridor
      • CVS: angina/coronary artery disease (CAD), MI, HTN, congestive heart failure (CHF), valvular disease, conditions requiring endocarditis prophylaxis, arrhythmia, peripheral vascular disease
      • GI: liver disease, gastroesophogeal reflux disease (GERD), vomiting, diarrhea, last meal
      • Renal: insufficiency, dialysis
      • Hematologic: anemia, coagulation disorders, sickle cell
      • Musculoskeletal (MSK) (arthritis - risk of C-spine subluxation during intubation)
      • Endocrine: diabetes, thyroid, adrenal
      • Other: morbid obesity, pregnancy, ethanol and drug use
    • Family history of malignant hyperthermia, atypical cholinesterase (pseudocholinesterase), or other abnormal drug reactions

    Anesthesia Physical Examination

    • Oropharynx + airway assessment to determine the likelihood of difficult intubation
      • No single test is specific or sensitive - all aid in determination of ease of intubation
      • Degree of mouth opening + TMJ subluxation
      • Jaw size (micro/retrognathia), "thyromental distance"
      • Tongue size
      • Posterior pharynx, tonsillar pillars, uvula easily visible
      • Dentition, dental appliances/prosthetics/caps - inform of possibility of damage
      • C-spine stability, neck flexion/extension
      • Tracheal deviation
      • Nasal passage patency (if planning nasotracheal intubation)
    • Mallampati classification of airways
      • Class 1: able to visualize soft palate, fauces, uvula, ant and post tonsillar pillars
      • Class 2: able to visualize all of the above, except anterior andposterior tonsillar pillars are hidden by the tongue
      • Class 3: only the soft palate and base of the uvula are visible
      • Class 4: only the soft palate can be seen (uvula not visualized)
    • For emergency operations, add the letter E after classification

    Anesthesia Patient Optimization

    • From the history, physical exam, and labs/investigations, the anesthetist can determine whether or not the patient is in OPTIMAL condition for the proposed surgical procedure
    • Goal is to optimize the non-surgical disease states prior to surgery
    • In emergency cases, it is not always possible to optimize coexistent or chronic disease states; goal is then to accomplish what is possible in the time available

    Postoperative Management

    • Usually begins in O.R. with discontinuation of anesthetic drugs and extubation (exception - if going to intensive care unit (ICU))
    • Patient can be transported to post-anesthesia care unit (PACU) when ABC's stable
    • Patient can be released from the unit when the PACU discharge criteria for ventilation, circulation, consciousness, motor function, and colour have been met
    • Potential complications:
      • CNS: agitation, delirium, somnolence
      • Respiratory: aspiration, upper airway obstruction, hypoxemia, alveolar hypoventilation, upper airway trauma (intubation/extubation)
      • CVS: hypothermia (rewarm patient), shivering (due to hypothermia or postanesthetic effect), hypotension, hypertension, dysrhythmias
      • GI: nausea and vomiting

    Regional Anesthesia Definition

    • Local anesthetic applied around a peripheral nerve at any point along the length of the nerve (from spinal cord up to, but not including, the nerve endings) for the purposes of reducing or preventing impulse transmission
    • No CNS depression (unless overdose (OD) of local anesthetic); patient conscious
    • Regional anesthetic techniques categorized as follows:
      • Epidural and spinal anesthesia
      • Peripheral nerve blockades
      • IV regional anesthesia

    Regional Anesthesia Preparation

    • Patient Preparation:
      • Thorough pre-op evaluation and assessment of patient
      • Technique explained to patient
      • IV sedation may be indicated before block
      • Monitoring should be as extensive as for general anesthesia
    • Nerve Localization:
      • Anatomical landmarks, local anatomy (e.g. line joining iliac crests crosses L3-L4 interspace; axillary artery as guide to brachial plexus)
      • Paresthesias and peripheral nerve stimulation used as a guide to proper needle placement

    Relative Indications for Regional Anesthesia

    • Avoidance of some of the dangers of general anesthesia (e.g., known difficult intubation, severe respiratory failure, etc.)
    • Patient specifically requests regional anesthesia
    • For high quality post-op pain relief
    • General anesthesia not available

    Contraindications to Regional Anesthesia

    • Allergy to local anesthetic
    • Patient refusal, lack of cooperation
    • Lack of resuscitation equipment
    • Lack of IV access
    • Coagulopathy
    • Certain types of preexisting neurological dysfunction
    • Local infection at block site

    Complications of Regional Anesthesia

    • Failure of technique
    • Systemic drug toxicity due to overdose or intravascular injection
    • Peripheral neuropathy due to intraneural injection
    • Pain or hematoma at injection site
    • Infection

    Nerve Fibres

    • Different types categorized as follows:
      • ...

    Inspired Oxygen Dilution

    • Inspired oxygen (O2) can be diluted by room air
    • Facial masks with an O2 reservoir deliver O2 concentrations greater than 60%
    • An O2 flow rate of 6L/min provides 60% O2, and each increase of 1L/min O2 concentration by 10%

    High Flow Oxygen Systems

    • Venturi masks provide consistent and predictable inspired O2 concentrations (FIO2)
    • Venturi masks allow for the control of gas humidity

    Total Body Water (TBW)

    • In a 70kg adult, TBW accounts for 60% of total body weight
    • TBW is divided into intracellular fluid (ICF, 2/3) and extracellular fluid (ECF, 1/3)
    • ECF further comprises interstitial fluid (3/4) and intravascular fluid (1/4)
    • Starling's forces maintain the balance of intravascular fluid

    Fluid Balance and ECF Volume

    • ECF excess leads to pulmonary edema, dependent edema, S3 heart sound, and increased jugular venous pressure (JVP)
    • ECF deficit causes decreased JVP, hypotension, tachycardia, dry mucous membranes, decreased skin turgor, lethargy, weight loss, sunken eyes, decreased urine output, and depressed fontanelle in infants
    • Hematocrit decreases with ECF expansion and increases with ECF deficit
    • Fluid intake and output determine total body fluid balance, which is influenced by renal function, syndrome of inappropriate ADH secretion (SIADH), diabetes insipidus (DI), osmoles, and drugs (diuretics)

    IV Fluid Therapy

    • Total fluid requirement is calculated by adding maintenance, deficit, and ongoing losses, and subtracting oral intake, total parenteral nutrition (TPN), and medication solutions
    • Dehydration is classified into mild (less than 5% TBW loss), moderate (5-10% TBW loss), and severe (greater than 10% TBW loss)
    • Total sodium content controls ECF volume, while sodium concentration determines ICF volume

    Anaphylactic Shock

    • A rare but potentially lethal reaction in IgA deficient patients with anti-IgA antibodies
    • Immune complexes activate mast cells, basophils, eosinophils, and the complement system, causing symptoms after transfusion of blood products containing IgA
    • Symptoms include apprehension, urticarial eruptions, dyspnea, hypotension, laryngeal and airway edema, wheezing, chest pain, shock, and sudden death
    • Management involves circulatory support with fluids, catecholamines, bronchodilators, and respiratory assistance as indicated
    • A form of noncardiogenic pulmonary edema occurring 2-4 hours after transfusion
    • An immunologic cause, unrelated to fluid overload or cardiac failure
    • Respiratory distress ranging from mild dyspnea to severe hypoxia
    • Chest x-ray shows acute pulmonary edema, but pulmonary artery and wedge pressures are not elevated
    • Usually resolves within 48 hours with O2, mechanical ventilation, and supportive treatment

    Immunosuppression

    • Studies associate perioperative transfusion with postoperative infection, earlier cancer recurrence, and poorer outcome

    Immune-Hemolytic Transfusion Reactions

    • The most serious and life-threatening transfusion reaction
    • Caused by donor incompatibility with recipient blood

    Non-Immune Transfusion Reactions

    • Infectious risks include HIV, hepatitis, Epstein-Barr virus (EBV), cytomegalovirus (CMV), brucellosis, malaria, salmonellosis, measles, and syphilis
    • Hypervolemia and electrolyte changes, particularly increased potassium in stored blood
    • Coagulopathy, hypothermia, citrate toxicity, and hypocalcemia

    Shock

    • Remember that hypotension is not synonymous with shock
    • Shock refers to inadequate organ perfusion
    • General approach involves:
      • ABCs first
      • Identification of the cause
    • General management includes O2, fluids, inotropes, and monitoring urine output, vital signs, central venous pressure (CVP), and potentially pulmonary capillary wedge pressure (PCWP)
    • Beware of complications, such as hypovolemic shock leading to cardiac ischemia and cardiogenic shock

    Types of Shock

    • S: Septic/Spinal
    • H: Hemorrhage/Hypovolemia
    • O: Obstructive
    • C: Cardiogenic
    • K: Anaphylactic

    Septic Shock

    • Caused by bacterial (often Gram-negative), viral, or fungal infections
    • Endotoxins and mediators cause blood pooling in veins and capillaries
    • Associated with contamination of open wounds, intestinal injury, or penetrating trauma, and can occur with minimal history.
    • Clinical features include warm skin (fever), decreased JVP, wide pulse pressure, increased cardiac output (CO), decreased systemic vascular resistance, and increased heart rate (HR)
    • Initial treatment includes antibiotics and volume expansion

    Spinal/Neurogenic Shock

    • Decreased sympathetic tone
    • Hypotension without tachycardia or peripheral vasoconstriction, resulting in warm skin

    Preoperative Optimization

    • Diuretics, oral hypoglycemics, anticoagulants, steroids, monamine oxidase inhibitors (MAOI), and drugs with central nervous system (CNS) side effects can influence anesthetic procedures
    • Optimize medical treatment preoperatively to reduce peri- and postoperative complications:
      • Diabetes mellitus (DM): optimize glycemic control
      • Nutritional status: correct malnourished states
      • Smoking: encourage cessation
      • Obesity: encourage weight loss
      • Chronic obstructive pulmonary disease (COPD): optimize respiratory status, teach postoperative exercises (e.g., incentive spirometry)

    History

    • Gather information regarding:
      • Previous anesthetic experience and complications
      • Previous intubations
      • Medications
      • Drug allergies
      • Allergies to topical preparations
    • Conduct a focused review of systems:
      • CNS: seizures, transient ischemic attack (TIA), cerebrovascular accident (CVA), raised intracranial pressure (ICP), spinal disease, arteriovenous malformation (AVM)/aneurysm, neuromuscular disease
      • Resp: smoker, asthma, COPD, upper respiratory tract infection (URTI), dyspnea, stridor.
      • Cardiovascular (CVS): angina/coronary artery disease (CAD), MI, HTN, congestive heart failure (CHF), valvular disease, conditions requiring endocarditis prophylaxis, arrhythmia, peripheral vascular disease
      • GI: liver disease, gastroesophageal reflux disease (GERD), vomiting, diarrhea, last meal
      • Renal: insufficiency, dialysis
      • Hematologic: anemia, coagulation disorders, sickle cell
      • Musculoskeletal (MSK): arthritis (risk of C-spine subluxation during intubation)
      • Endocrine: diabetes, thyroid, adrenal
      • Other: morbid obesity, pregnancy, ethanol, and drug use

    Family History

    • Inquire about family history of malignant hyperthermia, atypical cholinesterase (pseudocholinesterase), or other abnormal drug reactions

    Oropharynx and Airway Assessment

    • Assess oropharynx and airway to determine the likelihood of difficult intubation
    • Multiple factors can affect intubation difficulty:
      • Degree of mouth opening and temporomandibular joint (TMJ) subluxation
      • Jaw size (micro/retrognathia)
      • "Thyromental distance"
      • Tongue size
      • Visibility of posterior pharynx, tonsillar pillars, and uvula
      • Dentition, dental appliances/prosthetics/caps
      • C-spine stability, neck flexion/extension
      • Tracheal deviation
      • Nasal passage patency (if planning nasotracheal intubation)

    Mallampati Classification of Airways

    • A classification system used to assess airway visibility:
      • Class 1: Visible soft palate, fauces, uvula, anterior and posterior tonsillar pillars
      • Class 2: Visible soft palate, fauces, uvula, but anterior and posterior tonsillar pillars are hidden by the tongue
      • Class 3: Only the soft palate and base of the uvula are visible
      • Class 4: Only the soft palate is visible (uvula not visualized)

    Local Anesthetics (LA)

    • LA provide sensory blockade while relatively preserving motor function
    • Used for both pain management and surgical procedures
    • Potential for toxicity

    Maximum Doses for Local Anesthetics

    • Always be aware of the maximum dose for the LA being used
    • Maximum dose is usually expressed as mg of LA per kg of lean body weight and as a total maximum dose
    • Maximum doses vary based on the specific LA:
      • Lidocaine: maximum dose 5 mg/kg (with epinephrine: 7 mg/kg)
      • Chlorprocaine: maximum dose 11 mg/kg (with epinephrine: 14 mg/kg)
      • Bupivacaine: maximum dose 2.5 mg/kg (with epinephrine: 3 mg/kg)

    Systemic Toxicity

    • Occurs due to accidental intravascular injection, LA overdose, or rapid absorption
    • Manifests primarily in the central nervous system (CNS) and cardiovascular system (CVS)
    • Initial CNS effects are excitatory due to blockade of inhibitory fibers, followed by blockade of excitatory fibers
    • CNS effects in approximate order of appearance:
      • Numbness of tongue, perioral tingling
      • Disorientation, drowsiness
      • Tinnitus
      • Visual disturbances
      • Muscle twitching, tremors
      • Convulsions, seizures
      • Generalized CNS depression, coma, respiratory arrest

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    Description

    This quiz explores the importance of pain control and monitoring during surgical procedures. It discusses various pain management techniques, including preemptive analgesia and patient-controlled analgesia, alongside the significance of monitoring for patient safety. Test your knowledge on these critical aspects of surgical care.

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