Pancuronium during mechanical ventilation speeds recovery of lungs of infants with hyaline membrane disease.

Spontaneous breathing during mechanical ventilation in newborn infants may damage the lung. To find out whether the prevalence of lesions which might be due to trauma was reduced by muscle relaxation, fifty infants who required mechanical ventilation of hyaline membrane disease were randomly assigned to treated and control groups. The treated infants were kept muscle relaxed with pancuronium bromide until they needed a FiO2 of 0.40 or less during ventilation. The mean birthweight, gestational age, age at entry to the trial, duration of intubation and ventilation, FiO2 during the acute phase of the illness, and ventilator pressures were closely comparable in the two groups. Two of twenty-six treated infants and one of twenty-four controls died. Four treated and five control infants acquired pneumothoraces and/or interstitial emphysema. The length of time that the treated infants required added oxygen was significantly less than in the control infants. All treated infants were breathing room air spontaneously by one month of age whereas seven control infants were still dependent on added oxygen, needing an average FiO2 of 0.35 to achieve a mean PaO2 of 6.5 kPa (49 mm Hg). These seven infants required added oxygen until they were 5-18 (mean 10) weeks old. Muscle relaxation during mechanical ventilation for hyaline membrane disease speeds recovery of the lungs, probably owing to a reduction in traumatic damage.

Continuous monitoring of arterial oxygen tension in infants: four years of experience with an intravascular oxygen electrode.

Two hundred eighty-two umbilical artery catheters with oxygen electrodes on their tips were passed into the aortas of 268 newborn infants with severe respiratory illnesses between 1974-1977; 254 (90%) of the electrodes recorded PaO2 satisfactorily for a mean of 66 hours; 212 (75%) electrodes were still functioning well when removed, because they were no longer clinically needed, after a mean of 87 hours. The 27 electrodes that failed to record PaO2 on insertion, 42 that failed later, and 25 that temporarily malfunctioned were examined after removal from the infants. A structural cause was found which accounted for the failure or malfunction of 43 electrodes. Problems with the remaining 51 electrodes were thought often to have been due to clotting over the tip of the electrode. The main complication of catheterization was temporary impairment of the circulation to the legs in 69 (26%) infants. Autopsies were done on 69 (85%) of the infants who died; 22 (32%) infants were found to have thrombi in an iliac artery, which spread in ten (15%) of the aorta. It was concluded that the intravascular electrode usually functioned satisfactorily and that the incidence of complications was no higher than that reported with ordinary umbilical artery catheters. Improvements in the performance of the catheter-tip electrode would be expected if structural causes for failure were eliminated and if means to reduce the incidence of clot formation around the catheter and electrode could be found. It is believed that intravascular electrodes cannot be replaced by skin electrodes for the initial management of severe respiratory illnesses.

Transcutaneous estimation of arterial PO2 and PCO2 in newborn infants with a single electrochemical sensor.

A transcutaneous electrochemical sensor designed to estimate arterial oxygen (PaO2) and carbon dioxide (PaCO2) tensions simultaneously and continuously was evaluated in newborn infants with respiratory illnesses. After calibration of the sensor against a sample of arterial blood from the infant, the accuracy of estimation of PaO2 and PaCO2 seemed sufficient for clinical purposes.

Referral of mothers and infants for intensive care.

During 1975-7, 96 mothers were referred to University College Hospital for delivery from 39 other hospitals because their pregnancies were considered to be at very high risk. One hundred of the 111 infants born to the 96 mothers weighed 2500 g or less and 60 weighed 1500 g or less. A high proportion of the infants developed serious illnesses necessitating intensive care. The birth-weight-specific neonatal mortality rates of the infants were much lower than those of infants born in England and Wales as a whole and were also lower than those of the 370 infants transported to this hospital for intensive care after delivery elsewhere. Whenever possible mothers with very high-risk pregnancies should be referred for delivery to centres with full facilities for the intensive care of the mother, fetus, and newborn infant.

Continuous comparison of in vitro and in vivo calibrated transcutaneous oxygen tension with arterial oxygen tension in infants.

Transcutaneous PO2 simultaneously recorded by Drager and Radiometer electrodes on the abdominal skin was compared for six-hour periods with aortic PaO2 recorded by a Searle intravascular oxygen electrode. Ten newborn infants with serious respiratory illnesses, six of whom needed mechanical ventilation, were studied. The skin electrodes were heated to 44 degrees C and calibrated first in vitro, and then in vivo against the infant's PaO2. The results showed that 1) after in vivo calibration both skin electrodes gave an accurate estimate of PaO2 for six hours without resiting of the electrodes; 2) the Radiometer electrode gave as satisfactory an estimate of PaO2 after in vitro as after in vivo calibration; 3) the Drager electrode gave a significantly less accurate estimate of PaO2 after in vitro than after in vivo calibration; 4) no evidence suggesting that peripheral vasoconstriction interfered with the accuracy of estimation of PaO2 by the skin electrodes was found.