Ara S. Moomjian

Improved oxygenation and lung compliance withprone positioning of neonates

Fourteen intubated infants recovering from neonatal respiratory disease had arterial blood gases and lung mechanics measured in the supine position and in two variants of the prone position. Prone positioning resulted in significant increases in mean (+/- SEM) arterial oxygen tension (Pa(o2 70.4 +/- 2.5 to 81.1 +/- 4.4mm Hg), dynamic lung compliance (1.7 +/- 0.24 to 2.55 +/- 0.37 ml/cm H2O),and tidal volume (8.6 +/- 1.0 to 10.5 +/- 1.2 ml) when all prone values were compared to supine values. Prone positioning with the abdomen protruding freely, when compared to all supine values, was associated with significantly increased dynamic lung compliance and tidal volume. Values for prone-abdomen free were not significantly different from values for prone-abdomen restricted. This suggests that there are clinical benefits from prone positioning in neonates recovering from respiratory disease.

Theophylline therapy in bronchopulmonary dysplasia.

BRONCHOPULMONARY DYSPLASIA is the most common neonatal pulmonarY disease requiring long-term mechanical ventilation. After establishing this diagnos!s, current therapy includes fluid restriction, diuretics, digitalization, and chest physiotherapy. During weaning and long-term management, several complications may occur, such as increased secretions, recurrent atelectasis, intermittent bronchospasm, and difficulty weaning from mechanical ventilation to continuous positive airway pressure. These complications may be related either to increased airway resistance or to unstable maintenance of lung volume; Although the pathologic changes in bronchopulmonary dysplasia result in increased airway resistance/there have been few clinical reports on the efficacy of bronchodilators for treating bronchopulmonary dysplasia? To establish the effect of theophylline therapy, a group 0fneonates with bronchopulmonary dysplasia .were treated with aminophylline intravenously, followed by measurements of serial pulmonary function tests and serum theophylline levels.

1000 NECROTIZING ENTEROCOLITIS-ENDEMIC VS. EPIDEMIC FORM

Necrotizing enterocolitis (NEC) is a disease of undefined etiology affecting premature infants. A number of hypotheses have been suggested for NEC, and clusters of cases have been reported in nurseries. During Dec. 1974 and Jan. 1975, 14 cases of NEC occurred in patients admitted to the infant ICU. In the 12 months prior to this period a total of 11 cases of NEC occurred. Distinguishing features of the epidemic group vs. the endemic group are summarized:Results of a stool culture survey showed an association between Klebsiella colonization and illness. In a 2 month period in 1976 a 2nd clustering of NEC occurred with characteristics similar to those described in the epidemic group above. The awareness of an epidemic form of NEC is important in evaluating the effects of therapy and/or prophylaxis of NEC in premature infants.

The effect of external expiratory resistance on lung volume and pulmonary function in the neonate

To investigate the acute physiologic effects of external expiratory resistance on lung function in extubated neonates recovering from respiratory disease, lung mechanics, respiratory patterns, and function residual capacity were measured in ten neonates during a control period and immediately after application of an external expiratory resistance of 30 cm H 2 O/l/second via a face mask. Following application of EER, mean FRC increased by 40.8% ( P

1242 THE EFFECTS OF DIFFERENT BODY POSITIONS ON PULMONARY FUNCTION IN NEONATES RECOVERING FROM RESPIRATORY DISEASE

To evaluate alterations in pulmonary function with positioning, 9 intubated neonates (wt. [mean] 2.3 kg., gest. age 34 wks., FiO2 .29, CPAP or PEEP 4 cm H2O) were studied in 4 positions (SC= supine control, PR=prone-abdomen restricted, PF=prone-abdomen hanging free, SF=supine followup). After 30 min. in each position; arterial blood gases, lung mechanics, and funct. residual cap. (FRC) were measured. Mean values in supine control were: pO2 67 torr, pC02 42 torr, RR 54 breaths/min., lung compliance (CL) 1.7 ml/cm H2O, tidal volume (VT) 4.15 cc/kg, minute ventilation (VE) 263 ml/kg/min, FRC 26 ml/kg. In PR compared to SC: pO2 increased 12 torr (mean); FRC decreased 15%. In the PF compared to SC: pO2 increased 15 torr, mean FRC was unchanged but increased in 5/8 pts. In PF compared to PR: pO2 increased 6 torr; mean FRC was unchanged but increased in 5/7 pts. All comparisons of CL, pCO2, VE between the above groups were unchanged. In SF compared to PF: pO2 decreased 9 torr, FRC decreased 27%, CL decreased 44%, pCO2 was unchanged, VE decreased 20%. Summary of trends: 1) compared to supine control pO2 increased in both prone positions and FRC decreased in prone-abdomen restricted; 2) PF was better of 2 prone positions for increasing FRC. This study demonstrates that prone positioning improves oxygenation in neonates and that the prone-abdomen free is the best prone position for increasing lung volumes in infants with respiratory disease.

1213 THE EFFECTS OF ALTERATION OF EXPIRATORY RESISTANCE ON PULMONARY FUNCTION (PF) IN THE NEWBORN

Studies post extubation in neonates recovening from respiratory disease have suggested that expiratory resistance (RE) plays a role in maintaining adequate lung volume. To evaluate effects of RE on PF, 6 previously intubated newborns who were breathing spontaneously in room air had PF measured after the application of 2 external expiratory resistances: EER1 = 30 cm H2O/L/sec and EER2 = 24 cm H2O/L/sec. PF tests including dynamic lung compliance (CL), inspiratory resistance (RI), RE, functional residual capacity (FRC), tidal volume (VT), and inspiratory:expiratory (I:E) ratio were studied in infants (mean wt. 2.26 kg., mean age studied 55 days [range 3-114] ) evaluated with a face mask, pneumotachograph, solenoid valve, and EER1 and EER2. Patients were studied at 4 phases: 0 resistance, EER1, 0 resistance, EER2. There was a mean 25.6% increase of FRC with EER1 (p<0.01) and mean 37.8% increase of FRC with EER2 (p<0.01). I:E ratio decreased by mean 16.0% (p<0.05) with EER1 and mean 22.6% (p<0.05) with EER2. CL, RI, and VT were unchanged at any phase. This study demonstrates that lung volume can be increased when an expiratory resistance is applied. Therefore, application of an expiratory resistance may prove to be useful in the prevention of atelectasis in neonates post extubation.

1036 A NEW DEVICE FOR DIAGNOSIS AND EVACUATION OF NEONATAL PNEUMOTHORACES

A closed system (CS) device with teflon needle, sideholes, and attached stopcock was compared to a Medicut needle to determine incidence of unintentional introduction of air during diagnosis, and efficiency of evacuation of neonatal pneumothoraces (PTX). Thoracentesis was evaluated in 10 white rabbits (1.3-1.6 kg) with the CS needle in R chest and Medicut in L chest. Evacuation of free intrapleural air following thoracentesis and evacuation of intentionally injected air (20 cc) was performed on both sides of the chest. Intrapleural pressure measurements, x-rays,and number ml. air evacuated were used to quantitate each step. The CS needle produced no air entry on x-ray and no changes (P>0.05) in (mean ± SEM) inspiratory pleural pressure (IPP) (-5.2 ± 0.62 cm H2O) or expiratory pleural pressure (EPP) (-0.94 ± 0.55). Medicut taps (4.5 sec. to position stopcock) resulted in PTX on x-ray in 70% of trials and significant increase (P<0.05) of 1.28 ± 0.28 cm H2O in IPP and 1.58 ± 0.36 cm H2O EPP from baseline values. 23.7 cc (mean) air was evacuated from Medicut side. After 20 cc injection of air on CS needle side, a mean of 25.0 cc air was removed. Complete air evacuation occurred in 90% of CS needle trials vs. 60% with Medicut. The CS needle was safer, and more efficient than Medicut in evacuating air. In addition, since it is an airtight system, the CS needle can be used for diagnosis of PTX without the risk of introducing air.