Podcast
Questions and Answers
Which of the following accurately describes the recommended Bispectral Index (BIS) range during general anesthesia and what physiological aspect does it primarily reflect?
Which of the following accurately describes the recommended Bispectral Index (BIS) range during general anesthesia and what physiological aspect does it primarily reflect?
- BIS range of 40 to 60, monitoring depth of anesthesia and absence of awareness. (correct)
- BIS range of 20 to 40, primarily indicating sufficient pain management.
- BIS range of 60 to 80, reflecting adequate muscle relaxation.
- BIS range of 80 to 100, ensuring rapid emergence from anesthesia.
During invasive blood pressure monitoring via radial artery cannulation, the Allen's test is performed to assess:
During invasive blood pressure monitoring via radial artery cannulation, the Allen's test is performed to assess:
- Adequate collateral circulation to the hand, reducing the risk of ischemia. (correct)
- Cerebral perfusion by monitoring cerebral blood flow.
- The degree of anticoagulation by measuring the partial thromboplastin time (PTT).
- The effectiveness of neuromuscular blockade by evaluating muscle strength.
How would you interpret the following scenario: During central venous catheter insertion, an increased CVP is observed alongside a decreased blood pressure in a patient, what is the MOST likely cause? Select the BEST answer.
How would you interpret the following scenario: During central venous catheter insertion, an increased CVP is observed alongside a decreased blood pressure in a patient, what is the MOST likely cause? Select the BEST answer.
- Air embolism causing acute hypotension, requiring immediate aspiration of air.
- The catheter is obstructed and needs immediate replacement.
- Hypovolemia requiring immediate fluid bolus administration.
- Right ventricular failure leading to fluid overload, suggesting the need to avoid administering fluids. (correct)
A patient develops increasing respiratory distress after insertion of a pulmonary artery catheter. Auscultation reveals decreased breath sounds on the left, and the pulmonary artery wedge pressure suddenly increases. What is the MOST likely complication?
A patient develops increasing respiratory distress after insertion of a pulmonary artery catheter. Auscultation reveals decreased breath sounds on the left, and the pulmonary artery wedge pressure suddenly increases. What is the MOST likely complication?
What condition is most likely indicated by a pulse oximetry reading that falsely elevates SpOâ‚‚ levels?
What condition is most likely indicated by a pulse oximetry reading that falsely elevates SpOâ‚‚ levels?
When assessing a capnography waveform, what does an increased upstroke of phase III typically indicate, and what is the most likely underlying cause?
When assessing a capnography waveform, what does an increased upstroke of phase III typically indicate, and what is the most likely underlying cause?
A patient exhibits a 'shark fin' pattern on capnography. What is the MOST likely cause?
A patient exhibits a 'shark fin' pattern on capnography. What is the MOST likely cause?
What does the presence of a curare cleft on a capnography waveform usually suggest, and how should it be managed during surgery?
What does the presence of a curare cleft on a capnography waveform usually suggest, and how should it be managed during surgery?
A patient is undergoing mechanical ventilation, and the capnography waveform shows a sudden return to baseline after each breath. What is the most likely cause of this waveform?
A patient is undergoing mechanical ventilation, and the capnography waveform shows a sudden return to baseline after each breath. What is the most likely cause of this waveform?
During anesthesia, a patient's capnography shows an elevated baseline. Which of the following is the MOST likely cause?
During anesthesia, a patient's capnography shows an elevated baseline. Which of the following is the MOST likely cause?
What is the significance of a "step ladder pattern" observed on capnography and what immediate action should be taken?
What is the significance of a "step ladder pattern" observed on capnography and what immediate action should be taken?
If a patient undergoing general anesthesia suddenly exhibits a sharp decrease in EtCOâ‚‚ to zero, and the action that should be taken FIRST is:
If a patient undergoing general anesthesia suddenly exhibits a sharp decrease in EtCOâ‚‚ to zero, and the action that should be taken FIRST is:
During neuromuscular monitoring, a TOF ratio of > 0.9 indicates:
During neuromuscular monitoring, a TOF ratio of > 0.9 indicates:
During the intraoperative phase under general anesthesia, you notice a gradual fade response from the train-of-four (TOF) stimulation. What does this MOST likely indicate?
During the intraoperative phase under general anesthesia, you notice a gradual fade response from the train-of-four (TOF) stimulation. What does this MOST likely indicate?
Which body temperature measurement site is generally considered the MOST accurate for assessing core body temperature?
Which body temperature measurement site is generally considered the MOST accurate for assessing core body temperature?
Why is bladder temperature NOT a reliable indicator of core body temperature?
Why is bladder temperature NOT a reliable indicator of core body temperature?
Appropriate pre-oxygenation is critical before inducing anesthesia. Given a spontaneously breathing patient, what is the optimal method to maximize apnea time and what is the rationale behind it?
Appropriate pre-oxygenation is critical before inducing anesthesia. Given a spontaneously breathing patient, what is the optimal method to maximize apnea time and what is the rationale behind it?
What is the primary disadvantage associated with using a Guedel's airway?
What is the primary disadvantage associated with using a Guedel's airway?
What are the contraindications for using a nasopharyngeal airway?
What are the contraindications for using a nasopharyngeal airway?
What is the main purpose of employing the sniffing position during laryngoscopy, and how is this position achieved?
What is the main purpose of employing the sniffing position during laryngoscopy, and how is this position achieved?
During laryngoscopy, when using a Macintosh (curved) blade, which anatomical structure is the primary landmark for correct placement?
During laryngoscopy, when using a Macintosh (curved) blade, which anatomical structure is the primary landmark for correct placement?
When performing direct laryngoscopy with a Miller blade on a pediatric patient, what is the proper technique regarding the epiglottis, and why is it performed this way?
When performing direct laryngoscopy with a Miller blade on a pediatric patient, what is the proper technique regarding the epiglottis, and why is it performed this way?
What does the Cormack-Lehane grading system assess, and how does it influence the subsequent steps in airway management?
What does the Cormack-Lehane grading system assess, and how does it influence the subsequent steps in airway management?
During an intubation attempt the stylet is used. What best describes the PRIMARY purpose of using a stylet during endotracheal intubation?
During an intubation attempt the stylet is used. What best describes the PRIMARY purpose of using a stylet during endotracheal intubation?
Which of the following is the MOST appropriate action to take after several failed intubation attempts in a patient with a 'Can't Intubate, Can't Oxygenate' (CICO) scenario?
Which of the following is the MOST appropriate action to take after several failed intubation attempts in a patient with a 'Can't Intubate, Can't Oxygenate' (CICO) scenario?
In the Failed Intubation Algorithm, what is the MOST appropriate next step after failed intubation attempts and successful ventilation with a supraglottic airway device (SAD)?
In the Failed Intubation Algorithm, what is the MOST appropriate next step after failed intubation attempts and successful ventilation with a supraglottic airway device (SAD)?
Which of the following is the MOST critical benefit of using a flexible fiberoptic bronchoscope for endotracheal intubation?
Which of the following is the MOST critical benefit of using a flexible fiberoptic bronchoscope for endotracheal intubation?
Why is capnography considered the surest sign of correct endotracheal tube placement?
Why is capnography considered the surest sign of correct endotracheal tube placement?
During a rapid sequence intubation (RSI), what is the purpose of Sellick's maneuver, and how is it correctly performed?
During a rapid sequence intubation (RSI), what is the purpose of Sellick's maneuver, and how is it correctly performed?
In the context of airway management and rapid sequence intubation (RSI), under what circumstances is the use of gentle positive pressure ventilation (PPV) permissible and what is the MAXIMUM pressure allowed?
In the context of airway management and rapid sequence intubation (RSI), under what circumstances is the use of gentle positive pressure ventilation (PPV) permissible and what is the MAXIMUM pressure allowed?
What is the purpose of a superior laryngeal nerve block? Select the BEST answer.
What is the purpose of a superior laryngeal nerve block? Select the BEST answer.
A patient is undergoing a surgical procedure in the prone position. Which type of endotracheal tube (ETT) is MOST appropriate to use in this situation, and why?
A patient is undergoing a surgical procedure in the prone position. Which type of endotracheal tube (ETT) is MOST appropriate to use in this situation, and why?
In single-lung transplants one may see 2 peaks occur in phase III of capnography. What does this indicate?
In single-lung transplants one may see 2 peaks occur in phase III of capnography. What does this indicate?
What is the PRIMARY role of a supraglottic airway device (SAD) in airway management?
What is the PRIMARY role of a supraglottic airway device (SAD) in airway management?
During anaesthesia, a patient who has a laryngeal mask airway (LMA) in situ begins to regurgitate. What type of LMA would be MOST appropriate to minimise the risk of aspiration?
During anaesthesia, a patient who has a laryngeal mask airway (LMA) in situ begins to regurgitate. What type of LMA would be MOST appropriate to minimise the risk of aspiration?
During general anesthesia, a patient's blood pressure waveform suddenly exhibits a prominent dicrotic notch. Which of the following factors is LEAST likely to contribute to this presentation, assuming the catheter is properly placed and functioning?
During general anesthesia, a patient's blood pressure waveform suddenly exhibits a prominent dicrotic notch. Which of the following factors is LEAST likely to contribute to this presentation, assuming the catheter is properly placed and functioning?
A patient undergoing general anesthesia exhibits a sudden decrease in exhaled tidal volume, while the EtCOâ‚‚ reading remains stable. Auscultation reveals bilateral wheezing. Which of the following interventions is MOST appropriate?
A patient undergoing general anesthesia exhibits a sudden decrease in exhaled tidal volume, while the EtCOâ‚‚ reading remains stable. Auscultation reveals bilateral wheezing. Which of the following interventions is MOST appropriate?
After inducing anesthesia, a patient's capnography waveform initially shows a normal pattern but quickly transitions to a prolonged phase II (expiratory upstroke) with a significantly reduced alveolar plateau (phase III). The respiratory rate and tidal volume have not been altered. What is the MOST likely cause of this change?
After inducing anesthesia, a patient's capnography waveform initially shows a normal pattern but quickly transitions to a prolonged phase II (expiratory upstroke) with a significantly reduced alveolar plateau (phase III). The respiratory rate and tidal volume have not been altered. What is the MOST likely cause of this change?
Despite optimal pre-oxygenation, during a rapid sequence intubation, an otherwise healthy patient desaturates to 85% SpOâ‚‚ after 45 seconds of apnea. Which physiological factor MOST likely explains this rapid desaturation?
Despite optimal pre-oxygenation, during a rapid sequence intubation, an otherwise healthy patient desaturates to 85% SpOâ‚‚ after 45 seconds of apnea. Which physiological factor MOST likely explains this rapid desaturation?
While preparing to intubate a patient with a known history of severe obstructive sleep apnea (OSA), you observe that the patient's Mallampati score is Class IV, and they have a short, thick neck. Which of the following pre-intubation strategies is MOST likely to improve the chances of successful first-pass intubation in this patient?
While preparing to intubate a patient with a known history of severe obstructive sleep apnea (OSA), you observe that the patient's Mallampati score is Class IV, and they have a short, thick neck. Which of the following pre-intubation strategies is MOST likely to improve the chances of successful first-pass intubation in this patient?
Flashcards
CNS monitoring
CNS monitoring
Depth of anesthesia; absence of awareness is monitored.
Bispectral Index (BIS)
Bispectral Index (BIS)
Analyzes EEG waveforms to assess anesthesia depth.
BIS Target Range
BIS Target Range
Recommended BIS range for general anesthesia.
ECG Lead for Arrhythmias
ECG Lead for Arrhythmias
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Non-Invasive BP monitoring
Non-Invasive BP monitoring
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Allen's Test
Allen's Test
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Central Venous Pressure (CVP)
Central Venous Pressure (CVP)
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Pulmonary Artery Catheter
Pulmonary Artery Catheter
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Pulmonary Capillary Wedge Pressure (PCWP)
Pulmonary Capillary Wedge Pressure (PCWP)
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Central Venous Catheter Complications
Central Venous Catheter Complications
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Pulmonary Artery Catheter Complication
Pulmonary Artery Catheter Complication
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Pulse Oximetry
Pulse Oximetry
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Pulse Oximetry Principle
Pulse Oximetry Principle
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Pulse Oximetry: Reduced Hb
Pulse Oximetry: Reduced Hb
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Pulse Oximetry: Oxygenated Hb
Pulse Oximetry: Oxygenated Hb
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Pulse Oximetry Limitations
Pulse Oximetry Limitations
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Capnography
Capnography
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Capnography Principle
Capnography Principle
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Normal EtCOâ‚‚
Normal EtCOâ‚‚
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Capnography Phase I
Capnography Phase I
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Capnography Phase II
Capnography Phase II
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Capnography Phase III
Capnography Phase III
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Capnography Phase IV
Capnography Phase IV
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Bronchospasm/Partially Obstructed ET Tube
Bronchospasm/Partially Obstructed ET Tube
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Curare Cleft
Curare Cleft
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Hypoventilation
Hypoventilation
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Step Ladder Pattern
Step Ladder Pattern
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Sudden Zeroing of EtCOâ‚‚
Sudden Zeroing of EtCOâ‚‚
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Neuromuscular Monitoring
Neuromuscular Monitoring
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Train of Four (TOF) Stimulation
Train of Four (TOF) Stimulation
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TOF Ratio
TOF Ratio
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Hypothermia
Hypothermia
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Neuro Site for Core Temp
Neuro Site for Core Temp
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Cardio Site for Core Temp
Cardio Site for Core Temp
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Oâ‚‚ flow with tight mask
Oâ‚‚ flow with tight mask
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Pre-oxygenation Position
Pre-oxygenation Position
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Triple Maneuver
Triple Maneuver
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Guedel's Airway
Guedel's Airway
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Guedel's Size
Guedel's Size
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Nasopharyngeal Airway
Nasopharyngeal Airway
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Laryngoscopy
Laryngoscopy
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Neck Extension
Neck Extension
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Cormack-Lehane Grading
Cormack-Lehane Grading
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Murphy's Eye Function
Murphy's Eye Function
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Microcuffed ETT
Microcuffed ETT
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Study Notes
Monitoring of Patient: CNS, CVS, RS
- Depth of anesthesia (Absence of awareness) is monitored
- CNS monitoring analyzes EEG waveforms, with a recommended GA range of 40-60
- CVS monitoring includes monitoring of HR, BP and ECG
- ECG monitoring specifically looks for arrhythmias and ischemia, focusing on Lead II
Non-Invasive vs Invasive Monitoring
- Non-invasive BP monitoring includes sphygmomanometer, palpation, auscultatory methods, and oscillatory (automatic) measurements
- Invasive BP monitoring is common with radial artery access, requires major surgery
- Allen's test checks for adequate collateral circulation
- Allen's test compresses both the radial arteries with 2 hands
- A negative Allen's test is normal
- Modified Allen's test compresses both radial and ulnar arteries
- A positive modified Allen's test is normal
Central Venous Catheter vs Pulmonary Artery Catheter
- A central venous catheter (CVP) measures right heart function, normal being 0-5 cm H2O, and monitors fluid status
- Decreased CVP + decreased BP indicates that fluids are needed
- Increased CVP + decreased BP (Pump failure) indicates that fluids should not be administered
- It allows long-term IV cannulation for TPN, inotropes, and cardiac medications
- A pulmonary artery catheter measures left heart functioning, specifically PCWP
- Normal PCWP is 12-16 mmHg, and increased PCWP indicates LV dysfunction
- It uses a redundant method
Complications
- Central venous catheters can cause arrhythmias
- Pulmonary artery catheters can cause arrhythmias
- Pulmonary capillary rupture is a dreaded complication
Pulse Oximeter
- Pulse oximeters measure oxygenation
- Emits red light (660 nm), which is absorbed by reduced Hb
- Emits infrared light (940 nm), which is absorbed by oxygenated Hb
- The principle uses Beer Lambert's law
- Limitations include carbon monoxide (CO) poisoning, which falsely elevates SpO2, and methemoglobin (met Hb) or dyes, which lower SpO2
Capnography
- Capnography monitors exhaled CO2 using infrared spectroscopy
- Normal EtCO2 range is 35-45 mmHg
Capnography Waveforms:
- Normal waveform takes a top hat shape
- Phase 1: Exhaled from dead space (No CO2)
- Phase II: Expiratory upstroke (Gases exhaled by upper alveoli)
- Phase III: Alveolar plateau phase (Gases exhaled from middle & lower alveoli)
- Phase IV: Inspiratory downstroke
Abnormal Waveforms
- Bronchospasm/Partially obstructed ET tube: Increased upstroke of phase III, Shark fin pattern
- Cardiogenic oscillations: Physiological in children because of thin chest wall
- Recovering from the effect of muscle relaxant: curare cleft is present
- During Sx, supplement with muscle relaxant. End of Sx, start reversal.
- Hypoventilation: Seen in opium poisoning (CNS depressant)
- Ladder pattern: Malignant hyperthermia
- Leaky sampling line: Dual plateau sign.
- Incompetent inspiratory valve: Delaying of phase IV.
- Rebreathing of CO2: Exhausted soda lime/inadequate fresh gas flow
- Single lung transplant: Two peaks in phase III
- Sudden zeroing of EtCO2: Accidental extubation/circuit disconnection (most common) and Venous air embolism
- Intubation into esophagus
Neuromuscular Monitoring
- Neuromuscular monitoring: Checks adequate muscle relaxation after Sx.
- Train Of Four (TOF) stimulation:
- Muscle contraction is noted with 4 equal supramaximal stimuli
- TOF ratio (4th stimulus/1st stimulus) >0.9
- Safe to extubate (Fully recovered from muscle relaxant)
- Constant diminution response, Normal DMR (Phase 1)
- Gradual fade response, Also in Phase II block of DMR
- Normal NDMR
Temperature Monitoring
- Hypothermia: Depressed hypothalamus, and chilled OT & IV fluids.
- Under anesthesia: Decreased Shivering threshold.
- Hyperthermia : Malignant hyperthermia and sepsis.
Measurement Sites
- Neuro Sx Tympanic membrane, nasopharynx
- Core body temperature: Cardio Sx pulmonary artery (most accurate)
- Other Sx lower esophagus common
- Intermediate: Rectum (Wards, casualty)
- Not reliable: Skin, Axilla
- Bladder temperature is not done due to affected urine flow rates
Airway Management and Equipments
- Pre-oxygenation delivers 100% O2 with tight fitting mask
- Normally, give 10-12 L (↑Apnea time up to 10 min) for 3 min
- In emergencies, give 8 Vital Capacity (VC) breaths for 1 min; or, Least preferred; 4 VC breaths for 30 seconds
- Place patient in slight head up position
- Triple manoeuvre:
- Head tilt
- Chin Lift
- Jaw thrust
- Trans-nasal Humidified Rapid Insufflation ventilatory Exchange (THRIVE)
- 60 L for 3 min ↑ Apnea time by 13 minutes
- NO DESAT : Directly to pharynx 15 L/min ↑ Apnea time by 9 minutes
- Guedel’s airway prevents tongue fall back and the Stimulates Gag reflex,
- Size: Angle of mouth to tragus/mandible
- Nasopharyngeal airway prevents collapse of the pharynx and there are a few contraindications: such as Children with adenoids, Base of skull fracture (Raccoon’s eye), and Coagulopathy
Laryngoscopy:
- Head & neck position : Neck extension; Oral axis is aligned with the other 2 axes
- 10-15 cm pillow helps align pharyngeal & laryngeal axes.
- Sniffing of morning air/Drinking of pint beer position
- Extension: At atlanto-occipital joint Macintosh/Curved blade is for adults while Miller’s/Straight blade is for children. Both use left hand with Insert from right corner of mouth. Note that Note : Do not bend at wrist joint. (Causes upper teeth injury.)
Grading
- Cormack-Lehane grading assesses visibility of glottic opening after laryngoscopy.
- Grade 1: Complete laryngeal aperture seen
- Grade II: Only posterior portion of laryngeal aperture seen
- Grade III: Only epiglottis seen
- Grade IV: Epiglottis not seen
Endotracheal Tube (ETT):
-
Types:
- Murphy’s eye: Alternate ventilation
- Pilot balloon: Inflates cuff.
- Guide: Crosses vocal cords
- Cuffed ETTPrevents aspiration Types of Cuffed ETT
-
Decrease Pressure, Increase Volume (PVC)
-
Increase Pressure, Decrease Volume (Red rubber) DISADVANTAGE, Pressure >25 cmH2O damages tracheal mucosa with increase Pressure, decrease Volume cuff
-
Narrowest part of larynx:
- Glottis : Adults Cuffed ET tube.
- Subglottis : Children Microcuffed(Recent recommendation) : Distal placement.
-
UNCuffed
Modifications
- Modified double lumen ETT that are used in lung Sx
- Flexometallic/Armoured tube: is used for Head & neck Sx or when the patient is in a prone position
- RAE ETT: South facing for Cleft lip surgeries, North facing for Lower lip Sx.
Gadgets for the ETT
- Added accessory gadgets such as Direct tracheal insertion from Passed in ETT with the bougie
- Advanced Gadgets: such as Flexible fibre optic bronchoscope: Used for Gold standard for ETT position in restricted mouth opening & lung Sx
- If there is a Capnography, this would signify the surest sign of intubation.
Laryngeal Mask Airway (LMA):
- First Generation Classical LMA : (Made of Latex) Easy to use and minimal neck movement
- Disadvantage : Doesn’t prevent aspiration.
- Avoid Emergencies, Prone position, Laparoscopy, Pregnancy.
- LMA Unique : Made of PVC and is Single use. Second generation
- Has a drain tube (For removal of aspirate).
- The Proseal LMA makes of PVC (Better sealing pressure) with the drain tube
- Also used in laparoscopic Sx & pregnancy But intubation [preferred]
Other devices
- Video/Airtraq/Bullard laryngoscope: Decrease the chances of aerosol contamination and give Health care worker protection
- IGEL drain tube, Made of silicon gel that mimic the shape of pharynx, and a No pilot balloon.
Intubation Conditions
- Manual in-line stabilization: Decrease Neck movement after RTA
- The Rapid sequence/Emergency intubation Sellick’s Maneuver should be Applying pressure on cricoid cartilage that causes Esophageal lumen occlusion.
RSI vs Modified RSI
- The Feature should be Induction agent & muscle relaxant administered quickly.
- The Procedure is to apply Cricoid pressure at (30 N), and Cricoid pressure is removed after Intubation & cuff inflation.
Muscle Relaxant
- For a short acting muscle relaxant, use Succinylcholine
- For induction AOC with Thiopentone sodium use Propofol, with gentle PPV (20 cm) permitted
Awake Intubation
- Superior laryngeal nerve, Blocks recurrent laryngeal nerve
Failed Intubation Plan
- Plan A to succeed theLaryngoscopy and intubate the trachea; If intubation is failed, plan B maintain oxygenation
- Next is to follow steps to maintain oxygenartion with Supraglottic Airway Device
Failed intubation and SAD does not work
- If Airway Device fails to work, Stop and think about possible Options (Consider risks & benefits)
-
- Wake the patient up
-
- Intubate trachea via the SAD.
-
- Proceed without intubating the trachea
-
- Can attempt a Tracheostomy/cricothyroidotomy
-
- If all attempts has failed, continue to wake patient up and assist with the Facemask ventilation plan C
Can’t intubate?
- If you are unbale to intubate and are Can’t Oxygenate (CICO) go to Plan D to assist with an Emergency front of neck access- This requires a Cricothyroidotomy
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