will also result. Ineffective compression occurs when the elbows are not locked, the rescuer is not directly over the sternum, or the hands are improperly placed on the sternum. PERFORMANCE AND REASSESSMENT OF CPR.—When one rescuer performs CPR, the ratio of compressions to ventilations is 15 to 2, and it is performed at a rate of 80 to 100 compressions per minute. Vocalize: “one and, two and, three and,...” until you reach 15. After 15 compressions, you must give the victim two slow ventilations (1 ½ to 2 seconds). Continue for four full cycles. Quickly check for the carotid pulse and spontaneous breathing. If there are still no signs of recovery, continue CPR with compressions. Reassess the patient every few minutes thereafter. If a periodic check reveals a return of pulse and respiration, discontinue CPR and place the victim in the recovery position. Continue monitoring the victim and be prepared to restart CPR . Two-Rescuer CPR If there are two people trained in CPR on the scene, one should perform chest compressions while the other performs ventilations. The compression rate for two-rescuer CPR is the same as it is for one-rescuer CPR: 80 to 100 compressions per minute. However, the compression-ventilation ratio is 5 to 1, with a pause for ventilation of 1 ½ to 2 seconds consisting primarily of inspiration. Exhalation occurs during chest compressions. Two-rescuer CPR should be performed with one rescuer positioned at the chest area and the other positioned beside the victim’s head. The rescuers should be on opposite sides of the victim to ease position changes when one rescuer gets tired. Changes should be made on cue without interrupting the rhythm. The victim’s condition must be monitored to assess the effectiveness of the rescue effort. The person ventilating the patient assumes the responsibility for monitoring pulse and breathing. To assess the effectiveness of the partner’s chest compressions, the rescuer should check the pulse during compressions. To determine if the victim has resumed spontaneous breathing and circulation, chest compressions must be stopped for 5 seconds at the end of the first minute (20 cycles) and every few minutes thereafter. NOTE: Although it has fallen out to favor with some agencies, two-person CPR remains a viable method of resuscitation. CPR for Children and Infants CPR for children (1 to 8 years old) is similar to that for adults. The primary differences are that the heel of only one hand is used to apply chest compressions, and ventilations are increased to a rate of 20 breaths per minute (once every 3 seconds). Chest compressions are performed on the lower half of the sternum (between the nipple line and the notch). The chest should be depressed approximately one-third to one-half (about 1 to 1 ½ inches) the total depth of the chest. For infants (under 1 year old), CPR is performed with the infant supine on a hard, flat surface. The hard surface may be the rescuer’s hand or arm, although using the arm to support the infant during CPR enables the rescuer to transport the infant more easily while continuing CPR. See figure 4-16. Once the infant is positioned on a hard surface, the airway should be opened using the head tilt-chin lift or jaw-thrust maneuver. Both maneuvers, however, must be performed very carefully and gently to prevent hyperextension of the infant’s neck. Pulselessness is determined by palpating the brachial artery (fig. 4-17). If the infant has no pulse and is not breathing, CPR must be started immediately. To perform CPR on an infant, place your mouth over the infant’s nose and mouth, creating a seal. Give two slow breaths (1 to 1 ½ seconds per breath) to the infant, pausing after the first breath to take a breath. Pausing to take a breath after the first breath of each pair of breaths maximizes oxygen content and 4-20 Figure 4-16.—Infant supported on rescuer’s arm, and proper placement of fingers for chest compressions.