- Stable or unstable?
- Is the patient in cardiopulmonary arrest? Initiate ACLS Protocol
- Assess the airway. Ensure the adequacy of oxygenation and ventilation
- Assess for hypotension. If patient is hypotensive, immediately communicate with the surgeon and examine the surgical field for possible causes. Then the following steps should be undertaken as necessary:
- Turn off the anesthetic vaporizer
- Administer crystalloid bolus as appropriate
- Administer atropine 0.01 mg/kg
- Consider epinephrine 10–50 μg IV bolus
- If necessary, start epinephrine infusion at 2 μg/min and titrate as necessary
- Consider intraoperative EKG, A-line, CVP monitoring
- Consider use of external pacemaker (transvenous or transcutaneous)
- Once patient is stabilized, or if stable, identify cause and treat: identify P waves and QRS complexes (see chapter 5):
- Each QRS is preceded by a P wave:
- Sinus bradycardia, sinus pause
- No P waves are visible:
- Irregular QRS rate: A-Fib with slow ventricular response
- Wide QRS: sinoatrial block
- There are more P waves than QRS complexes:
- PR getting longer, and then P without QRS: second-degree AV block Mobitz 1 (Wenckenbach)
- PR constant, occasional P without QRS: second-degree AV block Mobitz 2
- No relation between P and QRS: third-degree AV block
- Possible causes:
- Airway issues:
- Hypoventilation? Increase respiratory rate and/or tidal volume
- Hypoxia? Increase FiO2 and/or PEEP
- Consider a cardiopulmonary event:
- Tension pneumothorax
- Embolism—gas, amniotic, thrombus, fat
- Myocardial depression—drugs, ischemia, electrolytes, trauma
- Pharmacological cause:
- Volatile agent overdose (or adequate dosing in susceptible patient), induction drugs, succinylcholine (especially if redosing), neostigmine, opioids. Identify drugs given by surgeon (e.g., vasoconstrictors)
- Vagal reflex:
- Discontinue stimulation; atropine if needed
- Undetected blood loss:
- Obtain additional IV access and replace fluids. Ensure cross-matched blood is available; transfuse as needed
- Consider other causes:
- Regional/neuraxial anesthetics: Bezold–Jarisch reflex causing vasodilation + bradycardia up to arrest. Ensure normovolemia; administer epinephrine IV boluses (start 10–50 μg, increase if needed)
- Surgical factors: IVC compression, retractor placement, pneumoperitoneum
- Stable or unstable?
- Is the patient in cardiopulmonary arrest (e.g., ventricular fibrillation, pulseless ventricular tachycardia)? Initiate ACLS Protocol immediately
- What is the blood pressure?
- Hypertensive? (Consider hypertensive causes discussed in the section “Hypertension.”)
- Reconfirm blood pressure
- Turn off vaporizers
- Administer crystalloids appropriately
- Diagnose rhythm: See Chapters 5 and 16
- QRS duration <0.08 seconds:
- Regular: attempt vagal stimulus (carotid massage, ocular pressure, Valsalva, unless contraindicated):
- Each QRS is preceded by a P wave: SVT
- There are more P waves than QRS complexes: atrial flutter or reentrant tachycardia
- There are no P waves: A-Fib
- Each QRS is preceded by a P wave: reentrant tachycardia
- QRS duration >0.12 seconds:
- P not visible, or dissociated from QRS: ventricular tachycardia
- Each QRS is preceded by a P wave: SVT + BBB
- There are more P waves than QRS complexes: atrial flutter + BBB or reentrant tachycardia + BBB
- No P waves: A-Fib + BBB
- There are more P waves than QRS complexes: reentrant tachycardia + BBB
- Poorly tolerated tachycardia (altered mental status, shock, chest pain), sinus or otherwise?
- Sinus tachycardia? Identify cause ...
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