Thirty-nine critically ill infants with pulmonary disease received tolazoline because of severe hypoxemia refractory to administration of 100% O2 and mechanical ventilation. Twenty-seven (69%) of the infants responded with an increase in PaO2 greater than or equal to 20 torr in the first umbilical arterial gas after completion of the initial ten-minute infusion (1 to 2 mg/kg) of the drug. A response was not correlated with survival. The overall survival was 46%, essentially unchanged from our previous report (44%). Infants with hyaline membrane disease had the poorest survival rate (33%). Complications associated with the use of tolazoline occurred in 82% of the infants. A hypotensive reaction, defined as a 25% decrease in mean arterial pressure from the pre-tolazoline level, occurred in 67% of the infants, and more commonly in the infants with RDS (87%). In 11 infants who did not respond to the initial dose of tolazoline, the dose was increased up to 10 mg/kg/hour; only one infant responded, and eight (73%) had a hypotensive reaction.

Carbon Dioxide↗

PubMed1979

Resting oxygen consumption of premature infants covered with a plastic thermal blanket.

Premature infants in single-wall incubators covered with "thermal blankets" made of plastic packing material have large reductions in insensible water loss (IWL) compared with naked infants. We postulated that such reductions inevaporative heat loss would not result in decreases in caloric expenditure if body temperature were maintained by a servocontrolled heat source. Using an open-circuit technique, we measured oxygen consumption (VO2), carbon dioxide production (VCO2), heart rate (HR), respiratory rate (RR), and abdominal skin (Tabd), cheek, thigh, rectal, incubator air, wall, and room air temperatures in ten infants less than 37 weeks gestational age and from 2 to 24 days of age both naked and covered with a plastic thermal blanket. Tabd temperature was maintained between 36.2 and 36.8 C and rectal temperature between 36.8 and 37.2 C in each environment by manual or automatic servocontrol. A "resting state" was defined by using a combination of subjective and objective criteria. The mean values of VO2 during the "resting state" were 7.31 and 7.59 cc/kg of body weight per minute for naked and covered infants, respectively. There were no significant differences between mean values of VCO2, respiratory quotient, HR, RR, abdominal, cheek, thigh, or rectal temperatures in the two environments. Operant temperatures averaged 0.5 C lower when the infants were covered. These data support the hypothesis that decreases in insensible water loss do not necessarily imply reductions in caloric requirements in infants where Tabd is maintained by servocontrol.

Body Temperature Regulation↗

PubMed1979

Obstructive sleep apnea and near miss for SIDS: I. Report of an infant with sudden death.

An infant girl followed up from birth to death at the University Medical Center had ""congenital stridor'' and a ""near miss for SIDS'' event at 3 months of age. As part of an ongoing SIDS research project, she underwent 24-hour polygraphic monitoring at 21 weeks of age. Sudden infant death occurred within 30 hours after the polygraphic study. Polygraphic data obtained from this infant are compared with those from control infants and other infants with near miss for SIDS who were of similar ages. The number of mixed and obstructive respiratory events during sleep was abnormally high on the infant's recording. Histologic findings, involving particularly the midline structures of the brain stem, are discussed.

Apnea↗

PubMed1978

Why should we study the infant 'near miss for Sudden Infant Death'?

The use of 'near miss for Sudden Infant Death syndrome' infants as a model toward understanding the Sudden Infant Death syndrome has been questioned. Although there are numerous problems in delineating this patient population and defining events occurring during sleep, continuous polygraphic monitoring demonstrates potentially life-threatening events.

Bradycardia↗

PubMed1978

Minimal oxygen consumption in infants cared for under overhead radiant warmers compared with conventional incubators.

Infants under radiant warmers have large increases in insensible water loss compared with infants in single wall incubators. To answer the question of whether or not a minimal rate of oxygen consumption could be achieved under overhead radiant warmers, we measured oxygen consumption, carbon dioxide production, and abdominal skin, cheek, rectal, thigh, and environmental temperature in ten healthy newborn infants in incubators and radiant warmers, using each infant as his/her own control. The minimal VO2 ranged from 4.41 to 8.87 and from 4.35 to 9.06 cc/kg/minute in the incubator and radiant warmer, respectively. The differences were clearly not significant (paired Student t-test, P greater than 0.60). There were no significant differences between the respiratory quotients, VCO2, or abdominal skin, check, rectal or environmental temperatures. These data support the hypothesis that a thermoneutral environment can be provided with a radiant warmer and imply that large increases in insensible water loss can occur without affecting minimal oxygen consumption.

Birth Weight↗

PubMed1978

Apnea, hypoxemia, and aborted sudden infant death syndrome.

To find out whether there is any relationship between the ventilatory response to hypoxia and the sudden infant death syndrome (SIDS), we studied the effects of mild induced hypoxia (PIO2, 120 mm Hg = 17% oxygen) in 16 infants aged 2 weeks to 6 months. Eight had recurrent apneic spells (apnea group) (five had aborted SIDS and three had recurrent apnea in the intensive care nursery) and eight were "well" preterm infants about to fly in a pressurized airplane (PIO2, 120 mm Hg) (control group). Mean birth weights were 2,245 and 1,400 gm and mean gestational ages were 35 and 30 weeks. Postconceptual ages (41.8 and 41.3 weeks) were almost identical. Heart rate was obtained from an ECG, and respiratory rate and pattern were obtained from a pneumogram. In addition, end-tidal PCO2 and PN2 or PO2 were obtained with a nasal catheter and gas analyzers. In the apnea group with inhalation of 17% oxygen, we observed an increase in periodic breathing and an increase in both rate and total duration of respiratory pauses. In the control group there were no significant changes. Heart rate and PCO2 did not change in either group. Our findings suggest that infants prone to apnea may have unique respiratory responses to mild induced hypoxia.

Apnea↗

PubMed1977

Chronic pulmonary disease in neonates after artificial ventilation: distribution of ventilation and pulmonary interstitial emphysema.

To determine pulmonary function abnormalities in patients with neonatal bronchopulmonary dysplasia (BPD), we measured distribution of ventilation by nitrogen washout, minute and tidal volume, and arterial and alveolar gases in three groups of ten preterm infants with similar birth weights (mean = 1,340 g) and gestational ages (mean = 30.3 weeks). Infants in group A were never artificially ventilated, those in group B were ventilated but had no subsequent BPD, and those in group C were ventilated and developed BPD. Infants with BPD had severe maldistribution of ventilation (pulmonary clearance delay 223% versus 47% and 60% for groups A and B). They had decreased tidal volumes (5.3 ml versus 7.0 and 6.2 ml) and higher respiratory rates (60/min versus 47 and 48) but similar minute volumes. They also had increased PaCO2 (53.6 torr versus 41.9 and 43.4 torr) and increased arterial-alveolar carbon dioxide gradients (6.8 torr versus 3.1 and 1.8 torr). There was no statistically significant difference between groups B and C for the time spent in fractional inspired oxygen greater than 0.40 and greater than 0.60, or the time ventilated for intubated, or the incidence of patent ductus arteriosus. Early pulmonary interstitial emphysema was much more common in the infants who subsequently developed BPD (eight of ten versus two of ten, P less than .01).

Chronic Disease↗

PubMedDate not supplied

Rapid assessment of ventilation by measurement of carbon dioxide elimination during high-frequency ventilation of kittens.

Monitoring of the effectiveness of ventilation is a significant problem during high-frequency ventilation (HFV). The time necessary to achieve equilibrium of the arterial tension of carbon dioxide (Paco2) following step changes in ventilation is appreciable, because of large body stores of CO2. Waiting for Paco2 to reach equilibrium is not only time-consuming but a potentially dangerous means of monitoring ventilator adjustments during HFV. Five kittens of mean +/- SD 1,082 +/- 383 gm weight were studied during HFV, both with normal lungs and lungs injured by saline lavage-induced surfactant depletion. The transcutaneous tension of carbon dioxide (Ptcco2) was monitored continuously to determine the time required to achieve equilibrium of Paco2 following a step change in ventilation. The rate of pulmonary CO2 elimination (VECO2) was measured immediately before and immediately after (less than 12 sec) step changes in ventilation and was used to predict the change in Paco2 achieved once equilibrium was reestablished. With normal lungs, equilibration time following step changes in ventilation was found to be approximately 20 minutes. After step decreases in ventilation of the injured lung, achieving equilibrium state took significantly longer, approximately 30 minutes. The Paco2 predicted was significantly related to the change in Paco2 achieved at equilibrium for both normal and injured lung studies. We concluded that direct monitoring of VECO2 during HFV may be a useful clinical monitoring technique, allowing rapid and accurate assessment of the efficiency of ventilation following step changes in ventilation and potentially assisting in optimizing ventilator settings.

Animals↗

PubMedDate not supplied

Transcutaneous PO2 monitoring in infants with cyanotic congenital heart disease treated with prostaglandin E1.

Transcutaneous PO2 (tcPO2) has been shown to closely approximate arterial PO2 (PaO2) in infants with normal oxygenation (PaO2 60-100 mm Hg). During hypoxemia (PaO2 less than 60 mm Hg), or administration of vasoactive drugs, such as tolazoline, correlation is frequently so poor that tcPO2 monitoring is of little value. We examined the relationship of tcPO2 to PaO2 among 6 infants with cyanotic congenital heart disease who were receiving prostaglandin E1 (PGE1). Close, linear correlation was found, even during hypoxemia. We conclude that tcPO2 monitoring has potential clinical value in such patients.

Arteries↗

PubMedDate not supplied

Who is responsible for making medical decisions?

Explore the source record for details and available documents.

Cost Control↗

PubMedDate not supplied

Survey of sleeping position after hospital discharge in healthy preterm infants.

OBJECTIVE: To evaluate the prevalence of nonprone (supine or side) versus prone sleeping position in healthy preterm infants. STUDY DESIGN: A questionnaire on sleeping position was mailed to mothers of 167 preterm infants discharged from the intermediate nursery at Packard Children's Hospital at Stanford. The prevalence of nonprone sleeping at 1 month (term corrected age) and 3 months (2 months corrected age) after nursery discharge was analyzed by an unpaired t test. RESULTS: Nonprone position sleeping occurred in 64% initially and dropped to 35% at 2 months corrected age. CONCLUSIONS: Overall, nonprone sleeping was widespread in our healthy preterm infants after hospital discharge but may not persist. A majority of these infants were sleeping prone during a high-risk period for sudden infant death syndrome.

Child Development↗