Controlled evaluation of muscle relaxation in the ventilated neonate.

To assess the effects of muscle relaxation on the critically ill ventilated neonate, pancuronium bromide was administered for a 12-hour period to ten low-birth-weight neonates (960 to 2,000 gm) of 26 to 34 weeks gestation, all whom required mechanical ventilation and were studied within 48 hours of birth (six to 39 hours). The infants were also studied for a 12-hour period during which no pancuronium bromide was administered. During both study periods, the order of which was randomized, heart rate, blood pressure, PO2, and intracranial pressure were continuously measured. The amounts of handling during the pancuronium and control periods were similar. The results revealed a significantly greater duration of hypoxia (PO2 less than 50 torr) (56.1 vs 23.6 minutes, P less than .001) and hyperoxia (PO2 greater than 70 torr) during the control period (92.5 vs 13 minutes, P less than .001). Durations of intracranial pressure elevation 10 cm H2O above the infant's baseline were significantly less during paralysis (6.7 vs 58.8 minutes, P less than .001) as were spikes of intracranial pressure to greater than 25 cm H2O (1.6 vs 24.4, P less than .05). There was no significant improvement in blood gas values, fractional inspiratory oxygen, or ventilator settings during muscle relaxation. Pancuronium reduced periods of nonoptimal oxygenation and elevated intracranial pressure and may therefore help to decrease adverse sequelae for the low-birth-weight, ventilated neonate.

Acute cardiopulmonary effects of pancuronium bromide in mechanically ventilated newborn infants.

The short-term effects of muscle relaxation with pancuronium bromide on arterial blood gas values, heart rate, and arterial blood pressure were studied in 49 neonates receiving mechanical ventilation. After pancuronium administration, mean PaO2 increased from 61.9 +/- 30.0 to 80.9 +/- 52.8 mm Hg (P = 0.006), mean PaCO2 decreased from 40.1 +/- 13.0 to 37.5 +/- 13.3 mm Hg (P = 0.03), and mean heart rate rose from 146.2 +/- 24.9 to 161.0 +/- 20.5 beats/min (P less than 0.001). Arterial blood pressure did not change significantly. When results were analyzed by diagnosis (meconium aspiration syndrome, hyaline membrane disease, pneumonia), only infants with meconium aspiration syndrome had a significant improvement in oxygenation (P = 0.008). Six of 18 patients with hyaline membrane disease responded to muscle relaxation, with a decrease in PaO2 of 10 mm Hg or more. No significant correlation was found between change in PaO2 and birth weight, gestational age, postnatal age, or change in heart rate. A weak correlation (r = -0.37, P less than 0.006) was observed between change in PaO2 and change in PaCO2. Although the reasons for the divergence in response in different groups of patients are not entirely clear, the risk of deterioration with pancuronium therapy should be kept in mind, particularly if treatment in an infant with hyaline membrane disease is being considered.

The adult respiratory distress syndrome and pancuronium bromide.

The institution and maintenance of artificial ventilation for a patient with the adult respiratory distress syndrome (ARDS) is frequently difficult because the hypoxic patient is often confused, agitated, or combative. Pancuronium bromide, a recently introduced neuromuscular blocking agent, was used to facilitate artificial ventilation in 6 patients with ARDS. As compared with morphine sulfate and diazepam, pancuronium bromide has fewer cardiovascular and central-nervous system effects. It also has fewer cardiovascular effects than does curare, and its prolonged administration does not lead to a desensitization neuromuscular block as is seen with succinylcholine. However, continuous high-quality nursing care is necessary if this drug is used.