To guarantee the patency of the airway, the patient should be turned onto her back, the head tilted backwards, the chin lifted and the mouth opened and inspected for objects that may cause obstruction. Secretions may be aspirated if abundant and a Mayo tube temporarily introduced to prevent the tongue from occluding the airway, if endotracheal intubation cannot be immediately performed.

To maintain oxygen supply to the lungs, ventilation with a bag–valve mask should be immediately started at 15 cycles/min, using 100 % oxygen and 15 l/min, and thereafter adapting according to oxygen saturation levels, which should be kept over 90 %. After obtaining the necessary material, early endotracheal intubation should be performed to improve the efficacy of ventilation and prevent aspiration of gastric contents. The ventilation cycles described above are maintained. If available, capnography should be used to confirm correct tube placement, as well as the adequacy of ventilation and cardiac massage. Pulmonary auscultation is necessary to evaluate proper endotracheal tube placement and the presence of additional respiratory sounds. As soon as possible, arterial blood gas sampling should be performed to evaluate whether the objective of maintaining partial pressure of oxygen above 60 mmHg is being achieved.

With maternal loss of consciousness and an absent carotid pulse, immediate external cardiac massage should be started, independently of whether or not cardiac activity is detected on the electrocardiogram. A hard board should be placed underneath the woman, and if pregnancy is above 20 weeks, a hard object is placed under this board to create a 30° left tilt (Fig. 7.2 – left). The objective is to avoid aorto-caval compression by the pregnant uterus and the resulting decreased venous return from the lower limbs. If this is not immediately available, an alternative is to shift the abdomen laterally and displace the uterus to the left (Fig. 7.2 – centre).

Cardiac massage is performed by placing two interlocked hands on the inferior portion of the patient’s sternum and with the arms fully stretched, applying rhythmic compressions at 100 cycles per minute, depressing the sternum by about 5 cm (Fig. 7.2 – right). There is ample evidence that appropriately applied cardiac massage causes respiratory movements, so this should be the prioritised manoeuvre if no one is available to guarantee ventilation. Cardiac massage is only stopped for brief seconds every 2 min, to re-evaluate cardiac rhythm and the carotid pulse. The procedure is only abandoned when an adequate cardiac rhythm and pulse are detected, or when death is declared.