factor | Proposed Mechanism | Actions that might reduce the Likelihood of Autoresuscitation occurring |
---|---|---|
Poor controlled ventilation techniques | ||
1) Air trapping in the lungs causing hyperinflation | Caused by high tidal volume or rapid ventilation rates with insufficient time for exhalation. Releasing the positive intra-thoracic pressure will enable venous return to resume and restore the circulation [24, 38, 59, 64, 65, 74,75,76,77,78,79, 86, 98, 100,101,102]. Effect more pronounced in hypovolaemia [37, 64] and pre-existing obstructive airways disease, especially if not managed correctly [9, 59, 103]. | Avoid excessive ventilation (rate, tidal volume, or both) Exclude hyperinflation as a reversible cause of Pulseless Electrical Activity (PEA) by stopping ventilation and disconnecting the bag |
2) High intrathoracic pressure | Delays injected CPR drugs from reaching the heart and allows drugs to accumulate peripherally. Stopping positive airway pressure allows drugs to reach the heart resulting in beneficial effects [65, 80, 86]. | |
3) Hyperventilation | Deleterious effects on coronary perfusion pressure (CPP) [104]. | |
Delayed drug effects | In profound acidosis or impaired drugs delivery via peripheral or intraosseous lines [77,78,79]. | Â |
CPP as low as 15 mmHg can produce Return of Spontaneous Circulation after asystole | Intrinsic vasomotor function of capacitance and resistance blood vessels may maintain CPP so that even when resuscitation has ceased, CPP may be high enough to restart the heart [105]. | Careful consideration before terminating resuscitation if vasopressor infusions and/or mechanical ventilation are used |
Return of myocardial function following Termination of Resuscitation (TOR) | Myocardial reperfusion due to spontaneous dislodging of endovascular plaque from a coronary artery [7, 10, 38]. Might also possibly allow spontaneous defibrillation in refractory VF [8, 23, 60]. | Â |
Premature TOR | Failure to appreciate that transient asystole can occur immediately after defibrillation [23]. | Resuscitation should never be abandoned immediately after defibrillation. |
Resuscitation terminated prematurely before therapeutic measures could have adequate effect. | Careful consideration before terminating resuscitation especially if vasopressor infusions and/or mechanical ventilation are used. | |
Untreated reversible causes e.g. acid-base balance; electrolyte imbalance; hypothermia [68]. | Check for and correct all reversible causes of CA before considering TOR. | |
TOR in the presence of a potentially treatable cardiac rhythm (refractory VF, PEA, broad complexes, bradycardia) and not asystole. | Caution about which cardiac rhythms are acceptable for terminating resuscitation as in 30% of autoresuscitation cases, TOR had occurred in the presence of some cardiac electrical activity (i.e. not asystole) | |
TOR too soon after resuscitation started | Careful consideration of how long CPR has been employed before TOR | |
Procedural | Unobserved minimal vital signs (e.g. pseudo-PEA) due to clinician oversight [38, 81]. Misdiagnosis of death, perhaps due to failure to fully examine patient prior to declaring death. | A 10 min observation period with ECG is generally more appropriate than 5 min following TOR [2, 7,8,9,10,11, 14, 26, 60,61,62,63,64, 66, 76, 79, 81, 94, 95, 106, 107]. After the decision has been made to terminate resuscitation, chest compressions should not be restarted The possibility of autoresuscitation should not affect the decision about when to terminate resuscitation |
Resuscitation may exacerbate acute internal bleeding leading to hypovolaemic arrest | When resuscitation is stopped, the cardiovascular system stabilises [36]. | Observe the patient after TOR for 10 min. |