common accidents in vet med

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Questions and Answers

What is a potential consequence of elevated blood pressure greater than 90 mmHg?

Mild hypertension

Decreased respiratory acidosis

Central nervous system and cardiovascular depression (correct)

Enhanced cardiac contractility

Which of the following is NOT a treatment for hypercapnia?

Mechanical ventilation

Manual ventilation

Increasing fresh gas flow (correct)

Decreasing anaesthesia depth

What is a common cause of rebreathing of CO2 in respiratory systems?

Manual ventilation errors

Exhausted carbon dioxide absorber (correct)

Insufficient mixture of anesthetic gases

High tidal volume settings

Which condition can lead to airway obstruction during ventilation?

ET tube occlusion Signup and view all the answers

How can aspiration pneumonia be minimized during procedures?

Utilize a cuffed endotracheal tube Signup and view all the answers

What is the maximum weight limit for cats that affects perioperative considerations?

< 2 Kg or > 6 Kg Signup and view all the answers

Which technique is primarily used for the induction and maintenance of anesthesia?

Inhalant Induction Signup and view all the answers

What is a key concern when performing endotracheal intubation in cats?

Maintaining cuff pressure Signup and view all the answers

What is the significance of the studies referenced in the CEPSAF regarding anesthesia in small animals?

They identify risk factors for anesthetic-related death. Signup and view all the answers

Which of the following procedures is specifically mentioned in the context of managing ventilatory support?

Intermittent positive pressure ventilation (IPPV) Signup and view all the answers

What is the maximum blood volume loss after which a transfusion should be considered?

20% Signup and view all the answers

Which of the following are consequences of hypothermia during anesthesia?

Prolonged recovery Signup and view all the answers

Which intervention is recommended to prevent hypothermia during anesthesia?

Use warm fluids Signup and view all the answers

What clinical sign indicates inadequate depth of anesthesia?

Sudden increase in heart rate Signup and view all the answers

Which of the following factors increases the odds of peri-anesthetic mortality?

Increasing ASA status Signup and view all the answers

What is a potential consequence of hypothermia during surgery?

Increased oxygen consumption Signup and view all the answers

Which inhalational agent is used to increase the depth of anesthesia?

Propofol Signup and view all the answers

What is one strategy for active rewarming during anesthesia?

Increase ambient room temperature Signup and view all the answers

What is the recommended treatment protocol for regurgitation?

Head down position and suction Signup and view all the answers

Which drug can be used to address metabolic acidosis in case of acid regurgitation?

Sodium bicarbonate Signup and view all the answers

What defines hypoxaemia in terms of PaO2 levels?

PaO2 < 80 mmHg Signup and view all the answers

What is a potential consequence of untreated hypertension?

Retinopathy or blindness Signup and view all the answers

Which of the following could contribute to hypertension during anesthesia?

Pain or nociception Signup and view all the answers

Which drug can be utilized for vasodilation in hypertensive patients?

Acepromazine Signup and view all the answers

What body response occurs due to hemorrhage?

Increased cardiac output and minute ventilation Signup and view all the answers

What is the effect of hypoxaemia on cardiac rhythm?

Increases heart rate and arrhythmias Signup and view all the answers

What is one effective method to assist with difficult intubation?

Pre-oxygenation Signup and view all the answers

Which of the following is a common risk factor associated with anaesthetic related morbidity?

Existing respiratory issues Signup and view all the answers

What physiological effect do anaesthetic drugs have on respiratory function?

Decrease the activity of intercostal muscles Signup and view all the answers

What potential consequence can occur with hypoventilation during anaesthesia?

Decreased oxygen saturation Signup and view all the answers

Which of the following conditions can lead to hypercapnia during anaesthesia?

Hypoventilation Signup and view all the answers

What is the recommended action if a patient is suspected of having a difficult airway?

Utilize a retrograde intubation technique Signup and view all the answers

Which of the following factors does NOT contribute to atelectasis during anaesthesia?

Use of a stylet Signup and view all the answers

What is the effect of high ETCO2 levels (above 45 mmHg)?

Suggests hypoventilation Signup and view all the answers

What approach is appropriate for managing a tracheostomy in a veterinary patient?

Perform a temporal tracheostomy Signup and view all the answers

Which of the following symptoms is NOT typically associated with hypercapnia?

Increased respiratory rate Signup and view all the answers

Study Notes

Common Complications & Accidents in Veterinary Anaesthesia

The presentation covers common complications and accidents that can occur during veterinary anaesthesia.
Learning objectives include describing approaches to the prevention and management of adverse events during anaesthesia in domestic animals, and outlining common risk factors associated with anaesthetic-related morbidity and mortality.

Respiratory Complications - Difficult Intubation

Pre-oxygenation is crucial for difficult intubations.
Various sizes of endotracheal tubes (ET tubes) are available.
Using a stylet or bougie can guide the ET tube.
Changing patient position might be necessary.
Assessing the plane of anaesthesia is important.
Topical anaesthetics can help with laryngeal spasm in cats.
A flexible fibre-optic endoscope can aid in difficult intubations.
Oral masses, inability to open the mouth, and fractures can lead to difficult intubations.

Respiratory Complications - Difficult Intubation (Continued)

Techniques for successful intubation are described, including steps for managing the larynx, trachea, and avoiding distortion.

Respiratory Complications - Alternative Ways of Securing the Airways

Retrograde intubation and temporal tracheostomy are alternative airway management options.
Diagrams illustrate these procedures.

Physiology Recap

Anaesthetic drugs depress the respiratory centre, central and peripheral chemoreceptors, and intercostal muscles and diaphragm.
Position and high oxygen concentrations affect functional residual capacity (FRC), atelectasis, hypoventilation/hypercapnia, and hypoxaemia.
Other receptors (pain) and emotional stimuli act through the hypothalamus; higher brain centers (cerebral cortex) influence respiratory responses.

Respiratory Complications - Hypercapnia

Elevated etCO2 ( > 45 mmHg) indicates hypercapnia.
Causes include fever, hyperthermia, malignant hyperthermia, seizures, and hyperthyroidism.
Pulmonary perfusion and alveolar ventilation issues can contribute to hypercapnia.
Technical errors, like exhausted CO2 absorbers, faulty valves, or inadequate fresh gas flow, can also cause hypercapnia.
Hypoventilation can also lead to hypercapnia.

Respiratory Complications - Hypercapnia (Consequences)

Levels up to 60 mmHg can stimulate the sympathetic nervous system (SNS), potentially causing mild tachycardia and hypertension.
Levels between 60-90 mmHg result in vasodilation and tachycardia.
Higher levels (>90 mmHg) lead to central nervous system depression, respiratory acidosis, cardiac contractility impairment, arrhythmias, and potentially, death.

Respiratory Complications - Hypercapnia (Treatment)

Treatment focuses on addressing the underlying cause and decreasing the depth of anaesthesia.
Manual or mechanical ventilation may be needed.

Respiratory Complications - Rebreathing of CO2

Inspiration of CO2 (FICO2) can occur due to dead space.
Causes include inadequate fresh gas flow, insufficient expiratory time (high respiratory rate), and leaks in the inner tube Bain system.
A faulty CO2 absorber or dysfunctional inspiratory/expiratory valves can lead to CO2 accumulation.

Respiratory Complications - Airway Obstruction

ET tube occlusion (mucus, blood, mass, regurgitation) presents as a "shark fin" appearance on capnography.
Suction, re-intubation, and addressing bronchoconstriction (asthma) are important.
Kinked ET tubes or expiratory limb obstructions in the breathing system can cause blockages.

Respiratory Complications - Regurgitation

Regurgitation can lead to aspiration pneumonia.
Inappropriate fasting times, drugs, hiatal hernia, gastroesophageal reflux, lighter planes of anaesthesia, and position changes can cause it.
Prevention involves adequate fasting time, rapid sequence induction with a cuffed ET tube, ensuring the ET tube is slightly cuffed on extubation, adequate anaesthesia depth, avoiding position changes, and using drugs like Metoclopramide, Maropitant, or Omeprazole.

Respiratory Complications - Regurgitation (Treatment)

Treatment includes head-down positioning.
Suction and saline lavage are used to remove the material.
The pH of regurgitated material should be measured; if acidic, instil sodium bicarbonate diluted in water into the oesophagus.
Sedation should be administered with caution.

Respiratory Complications - Hypoxaemia

Low arterial oxygen (PaO2) concentration (< 80 mmHg) (SpO2 < 90%) constitutes hypoxaemia.
Causes include hypoventilation; impaired diffusion (e.g., pulmonary oedema, pneumonia, pulmonary fibrosis); ventilation/perfusion mismatch (e.g., increased dead space); and right-to-left shunts and inadequate inspired O2 (FiO2).
Hypoxaemia can lead to hypoxia at the cellular level.

Respiratory Complications - Hypoxaemia (Consequences)

Low oxygen levels (hypoxia) in tissues lead to anaerobic metabolism, generating lactate and causing metabolic acidosis.
Initially, the sympathetic nervous system (SNS) is activated, increasing heart rate (tachycardia) and myocardial contractility.
Myocardial oxygen demand increases, potentially causing arrhythmias.
Eventually, bradycardia, hypotension, and respiratory depression can occur.

Respiratory Complications - Hypoxaemia (Treatment)

Interventions include pre-oxygenation.
Oxygen administration is crucial.
Mechanical ventilation and recruitment manoeuvres for atelectasis improve oxygenation.
Improving cardiac output and arterial blood pressure supports improved perfusion.
Drugs like vasopressors and fluid therapy can assist with perfusion.
Identifying and treating underlying disease is essential.
Avoiding factors increasing oxygen consumption (e.g., pain, shivering, hyperthermia) optimizes oxygen use.

Respiratory Complications - Hypoventilation

Hypoventilation is inadequate alveolar ventilation.
Causes include positioning (abdominal distension, pregnancy, laparoscopic surgeries), pulmonary disease, airway obstruction, neuromuscular disease, drug-induced respiratory depression, pain, obesity, and hypothermia.

Respiratory Complications - Hypoventilation (Diagnosis and treatment)

Causes of hypoventilation include positioning, pulmonary disease, airway obstruction, neuromuscular disease, drug-induced respiratory depression, pain, obesity, and hypothermia.
Diagnostic measures include monitoring patient status and clinical signs.
Interventions consist of oxygen administration, manual or mechanical ventilation, recruitment manoeuvres, and addressing underlying causes.
Decreasing the depth of anaesthesia can also be crucial.

Respiratory Complications - Apnoea/Respiratory Arrest

Apnoea/respiratory arrest is a cessation of breathing.
Causes include drugs (induction agents, ketamine, opioids), excessive anaesthesia depth, vagal stimulation (intubation, visceral traction), weaning from mechanical ventilation, nerve damage, and cardiac arrest.
Treatments include oxygen administration, intubation and ventilation, reducing anaesthesia depth, and performing cardiopulmonary resuscitation (CPR).

Respiratory Complications - Tachypnoea

Tachypnoea is rapid breathing.
Causes include inadequate anaesthesia depth, nociception/pain, increased CO2 production (hyperthermia), hypoxaemia, hypercapnia, and specific drug administration (opioids in conscious animals).

Cardiovascular Complications - Bradycardia

Low heart rate (HR) results in decreased cardiac output and tissue perfusion.
Specific breeds and species may have inherently lower heart rates.
Causes of bradycardia include drugs (opioids, alpha 2 agonists), excessive anaesthesia depth, raised intracranial pressure (Cushing's reflex), vagal response (position changes, surgical manipulation), hypothermia, and electrolyte imbalances (e.g., high potassium).

Cardiovascular Complications - Atrioventricular Blocks (AV Blocks)

AV blocks involve disruptions in the electrical conduction between the atria and ventricles of the heart.
Treatments include drug reversal (e.g., alpha-2 agonists), administration of anticholinergic drugs, and pacemaker implantation.

Cardiovascular Complications - Tachycardia

Elevated heart rate (HR) decreases diastolic filling, leading to decreased coronary perfusion time and reduced myocardial output.
Causes include sympathetic nervous system (SNS) stimulation (pain, surgical stimulation), drugs (anticholinergics, ketamine), cardiac disease, anaemia, haemorrhage, hypovolemia, hypotension, hypoxaemia, and pheochromocytoma.
Treatment focuses on addressing underlying causes and potentially using beta-blockers.

Cardiovascular Complications - Ventricular Tachycardia

Ventricular tachycardia (VT) is a rapid heart rhythm originating from the ventricles.
Causes may include drugs, heart disease, and pain.
Treatment involves lidocaine bolus or continuous infusion and defibrillation for pulseless VT/V Fib.

Cardiovascular Complications - Hypotension

Hypotension is low blood pressure.
MAP (< 60-70 mmHg) and SAP (< 90 mmHg) measurements indicate hypotension.
Hypotension can stem from vasodilation, decreased preload, decreased contractility, and bradycardia.
Causes include anaesthetic drugs, hypothermia, sepsis, anaphylaxis, hypercapnia, dehydration, hypovolemia, third spacing (e.g., effusions, ascites), positive pressure ventilation, abdominal distension, low total body water (in geriatrics), structural cardiac disease, cardiac tamponade, inhalational agents, propofol, hypocalcaemia, acidosis, conditions specific to neonates/juveniles/pediatrics, etc.

Cardiovascular Complications - Hypotension (Treatment)

Treatments vary depending on the cause of hypotension.
Strategies might include adjusting volatile agent levels, managing fluid therapy to address reduced preload, using vasopressor drugs or positive inotropes to improve contractility, and addressing bradycardia if present.
Treating underlying causes is crucial.

Cardiovascular Complications - Hypertension

Hypertension is elevated blood pressure.
Increased myocardial workload and oxygen demand cause myocardial ischemia and arrhythmias.
Causes include pain/nociception, lighter anaesthesia planes, hypercapnia/metabolic acidosis/hypoxia, underlying cardiac or renal disease (e.g., CKD), and pheochromocytoma.

Cardiovascular Complications - Hypertension (Treatment)

Treatments for hypertension aim to identify and address the underlying cause, potentially adjusting anaesthesia or analgesic administration, using drugs that cause vasodilation (e.g., Acepromazine), and/or beta-adrenergic blockers (e.g., esmolol, propranolol).

Haemorrhage

Reduced blood volume (plasma volume and haemoglobin concentration) leads to decreased oxygen-carrying capacity.
Body response to blood loss (increased cardiac output, O2 extraction) occurs to a certain level before leading to hypoxaemia, lactic acidosis, and hypotension.
Blood volume estimation (e.g., PCV/TP) is essential before surgery.
Consider transfusion when blood loss exceeds 20% or clinical signs of hypoxia (e.g., tachycardia, hypotension) are observed.
Replace lost blood volume with appropriate blood products (whole blood, packed red blood cells, or hemoglobin-based oxygen carriers).

Hypothermia

Hypothermia is abnormally low body temperature.
Target temperature is often approximately 38.5°C for dogs and cats.
Causes include the effects of anaesthetic drugs on the thermoregulatory centre and exposure to cold ambient temperatures related to the skin and body cavities.
Redistribution of heat through vasodilation from the core to the periphery is a response, but it takes several phases.
Heat is lost through conduction, convection, radiation, and evaporation.

Hypothermia (Consequences)

Consequences of hypothermia include decreased metabolism, prolonged recovery, vasoconstriction, increased oxygen consumption, shivering, hypoventilation, increased wound infections, and impaired coagulation.
Increased intraoperative blood loss, and higher risks of post-operative complications and hospitalization can occur.

Hypothermia (Treatment and Prevention)

Strategies for treating or preventing hypothermia include minimizing cold exposure of the animal by minimizing clipping, using prewarming measures, ensuring ambient temperature is warm, using appropriate warm fluids, close patient monitoring, using low gas flow, and administering and active rewarming techniques.

Inadequate Depth of Anaesthesia

Signs of inadequate anaesthesia depth include increased HR and arterial blood pressure.
Respiratory rate and pattern changes, eye position changes/strong palpebral reflexes/jaw tone changes may also be clinical signs.
It is important to distinguish these signs from those of nociception.
Inhalational agent levels, propofol, alfaxalone, and ketamine levels should be adjusted.

The Seven "H"s of Anaesthesia

A summary of common adverse events observed during veterinary anaesthesia: hypothermia, hyperthermia, hypercapnia, hypocapnia, hypotension, haemorrhage, and hypoxaemia.

Confidential Enquiry into Perioperative Small Animal Fatalities (CEPSAF)

CEPSAF studies risks factors related to peri-anaesthetic mortality.
Factors include: increasing ASA status, urgent/emergency procedures, major vs. minor procedures, age (over 12 years), weight (under 5kg for dogs, <2kg or >6kg for cats), inhalant induction, intermittent positive pressure ventilation (IPPV), sedation, endotracheal intubation in cats, and fluid therapy in cats.

References

Several veterinary anaesthesia textbooks and research articles are cited, providing evidence within the slides.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the consequences of elevated blood pressure, treatments for hypercapnia, and common causes of CO2 rebreathing. This quiz also covers airway obstruction conditions and strategies to minimize aspiration pneumonia during procedures.