CARDIAC MASSAGE

If the heart rate at 1 minute or less of age is below 100 beats/min, the trachea should be intubated, the lungs ventilated with oxygen, and closed chest massage begun. Both thumbs are placed at the junction of the lower and middle third of the body of the sternum, and the fingers, which encircle the chest, should be used to support the back ( Fig. 59-11 ). The sternum is compressed 1 to 2 cm (approximately one third of the distance to the anterior vertebral bodies) at a rate of 100 to 150 times per minute. This form of chest compression is more effective and better tolerated by the provider than two-finger massage.^[102] It is not necessary to interrupt ventilation of the lungs during cardiac massage and vice versa, although the American Heart Association suggests that this be done. Cardiac output is often greater when cardiac massage and ventilation are done simultaneously. The effectiveness of cardiac massage is determined by measuring the blood gases and pH and the arterial pressure generated and by examining the pupils. If the cardiac massage and ventilation are effective, the pupils will be in the midposition or constricted. If the pupils are dilated and no atropine has been given, cerebral blood flow and oxygenation are inadequate.

Ideally, each chest compression should generate a systolic pressure of 80 mm Hg; pressure is related to cardiac output during CPR.^[103] This pressure plus a cardiac massage rate of about 120 times per minute can maintain a diastolic blood pressure of 20 to 25 mm Hg. This level of diastolic pressure is adequate to maintain coronary artery perfusion in neonates during diastole. Failure to generate these pressures and rates allows the diastolic pressure to fall below 10 mm Hg, which is inadequate to perfuse the coronary arteries during diastole.