Basic life support (BLS)

Basic life support (BLS) includes those fundamental principles that are taught to the general public but applies equally to OR situations. A cardiac arrest should be suspected in any person unexpectedly found unconscious. If the subject cannot be aroused, the 2010 AHA guidelines for CPR and ECC stress immediate activation of the emergency response system and initiation of chest compressions to provide Circulation prior to Airway management and Breathing (C-A-B). The vast majority of cardiac arrest in adults is due to VF or pulseless VT, etiologies in which early chest compressions and defibrillation are most critical. The C-A-B sequence minimizes delay associated with opening the airway and associated positioning, obtaining a seal for mouth-to-mouth breathing, or obtaining bag-mask equipment. Beginning with chest compressions may also increase likelihood that bystanders will perform CPR on persons who have suffered from SCA, since laypersons and some health care providers may find airway management a challenging first step and therefore be hesitant to initiate CPR. For lone rescuers, the lay public is taught the “phone first/phone fast” rule (evidence class indeterminate). For adults, children aged 8 years and older, and all children known to be at high risk for arrhythmias, the emergency medical system (911; EMS) should be activated (phone first) before attempts at resuscitation by a lone rescuer. An initial resuscitation attempt followed by the activation of EMS (“phone fast”) is indicated for children less than 8 years old and for all ages in cases of submersion or near drowning, arrest secondary to trauma, and drug overdose.

1. Circulation. The patient should be on a firm surface (e.g., backboard) with the head on the same level as the thorax. The rescuer (surgeon in the OR) compresses the sternum between the nipples with the heel of one hand, the other hand on top of the first so that the hands are overlapped and parallel (evidence class IIa), shoulders positioned directly over the patient, and elbows locked to depress the chest to a depth of 1.5 inches (infants) and of at least 2.0 inches in children and a normal-sized adult. The chest compression rate is 100/minute at a compression–relaxation ratio of 1:1. For a single rescuer, the compression–ventilation ratio is 30:2. Unlike adults, in children, the compression–ventilation ratio becomes 15:2 if there are 2 rescuers. For a prone patient in the OR who cannot be quickly turned supine for CPR, one rescuer can place a clenched fist between the subxiphoid area and the OR table while compressions are administered over the corresponding region of the back. If an advanced airway (i.e., endotracheal tube or laryngeal mask airway) is in place during two-rescuer CPR, ventilations should be given at a rate of 8 to 10 breaths/min, chest compressions at a rate of 100/min without pauses for ventilation, and compressions are not synchronized between breaths.
2. Airway and breathing. Spontaneous ventilation is evaluated by observation and auscultation and is aided by repositioning (chin lift and jaw thrust) or insertion of an oropharyngeal or nasopharyngeal airway. If the patient is apneic or has ineffective spontaneous breaths (e.g., gasping only), rescue breathing or ventilation by bag-valve-mask with 100% O₂ is started. Two slow breaths at low airway pressures (to limit gastric distention) are first given, followed by ventilation with a respiratory rate of 8 to 10 breaths/min. If ventilation is not possible after these maneuvers, efforts to clear the airway of a suspected foreign body (e.g., Heimlich maneuver, chest compressions, or manual removal) should be attempted.
3. Defibrillation within 3 minutes in the hospital (evidence class I) and 5 minutes after calling the EMS (along with immediate high-quality CPR) is the major determinant of a successful resuscitation, since VF is the most likely etiology of a cardiac arrest in adults. Public access defibrillation programs have enabled “level I” responders (e.g., fire personnel, police, security guards, and airline attendants) to employ readily accessible automated external defibrillators (AEDs). AEDs are small, lightweight devices that use adhesive electrode pads for both sensing and delivering shocks. Visual and voice prompts are provided to assist the operators. The AED, after analysis of the frequency, amplitude, and slope of the ECG signal, advises either “shock indicated” or “no shock indicated.” The AED is manually triggered and does not automatically defibrillate the patient. AEDs are now also equipped with pediatric pad-cable systems that attenuate the adult dose to smaller dose appropriate for children. The dose attenuators should be used in children less than 8 years of age and less than 25 kg in weight. For infants, manual defibrillator is recommended but if unavailable AED with or without an attenuator can be used.
4. Reassessment. CPR should be resumed immediately after defibrillation (without checking for a pulse or rhythm) and continued for five cycles (or about 2 minutes if an advanced airway is in place) after which time the rhythm should be checked. For health care providers, if there is evidence for a perfusing rhythm, the pulse should be checked to determine if there is ROSC. If a nonshockable rhythm or no pulse is detected, CPR should be resumed, with rhythm checks every five cycles.