Rakesh Sahni

Congenital diaphragmatic hernia: Survival treated with very delayed surgery, spontaneous respiration, and no chest tube

This report suggests that stabilization of the intrauterine to extrauterine transitional circulation combined with a respiratory care strategy that avoids pulmonary overdistension, takes advantage of inherent biological cardiorespiratory mechanics, and very delayed surgery for congenital diaphragmatic hernia results in improved survival and decreases the need for extracorporeal membrane oxygenation (ECMO). This retrospective review of a 10-year experience in which the respiratory care strategy, ECMO availability, and technique of surgical repair remained essentially constant describes the evolution of this method of management of congenital diaphragmatic hernia.

Effects of quality of energy intake on growth and metabolic response of enterally fed low-birth-weight infants

Carbohydrate and fat may vary in their ability to support protein accretion and growth. If so, variations in the source of nonprotein energy might be used to therapeutic advantage in enterally fed low-birth-weight infants. To test the hypothesis that high-carbohydrate diets are more effective than isocaloric high-fat diets in promoting growth and protein accretion, low-birth-weight infants weighing 750–1600 g at birth were randomized in a double blind study to receive one of five formulas differing only in the quantity and quality of nonprotein energy. Groups 1, 2, and control received 130 kcal·kg−1·d−1 with 35, 65, and 50% of the nonprotein energy as carbohydrate. Groups 3 and 4 received energy intake of 155 kcal·kg−1·d−1 with 35 and 65% of the nonprotein energy as carbohydrate. Protein intake of all groups was 4 g·kg−1·d−1. Growth and metabolic responses were followed weekly, and macronutrient balances including 6-h indirect calorimetry were performed biweekly. Greater rates of weight gain and nitrogen retention were observed at high-carbohydrate intake compared with high-fat intake at both gross energy intakes. Greater rates of energy storage and an increase in skinfold thickness were observed in group 4 (high-energy high-carbohydrate diet) despite higher rates of energy expenditure. These data support the hypothesis that at isocaloric intakes, carbohydrate is more effective than fat in enhancing growth and protein accretion in enterally fed low-birth-weight infants. However, a diet with high-energy and high-carbohydrate content also results in increased fat deposition.

Randomised controlled trial of thiopental for intubation in neonates

AIMS To determine the effects of premedication with thiopental on heart rate, blood pressure, and oxygen saturation during semi-elective nasotracheal intubation in neonates. METHODS A randomised, placebo controlled, non-blinded study design was used to study 30 neonates (mean birthweight 3.27 kg) requiring semi-elective nasotracheal intubation. The babies were randomly allocated to receive either 6 mg/kg of thiopental (study group) or an equivalent volume of physiological saline (control group) one minute before the start of the procedure. Six infants were intubated primarily and 24 were changed from orotracheal to a nasotracheal tube. The electrocardiogram, arterial pressure wave, and transcutaneous oxygen saturation were recorded continuously 10 minutes before, during, and 20 minutes after intubation. Minute by minute measurements of heart rate, heart rate variability, mean blood pressure (MBP) and transcutaneous oxygen saturation (SpO2) were computed. The differences for all of these between the baseline measurements and those made during and after intubation were determined. Differences in the measurements made in the study and the control groups were compared using Students t test. RESULTS During intubation, heart rate increased to a greater degree (12.0vs −0.5 beats per minute, p < 0.03) and MBP increased to a lesser degree (−2.9 vs4.4 mm Hg; p < 0.002) in the infants who were premedicated with thiopental. After intubation only the changes in MBP differed significantly between the two groups (−3.8vs 4.6 mm Hg; p < 0.001). There were no significant changes in the oxygen saturation between the two groups during or after intubation. The time taken for intubation was significantly shorter in the study group (p < 0.04). CONCLUSIONS The heart rate and blood pressure of infants who are premedicated with thiopental are maintained nearer to baseline values than those of similar infants who receive no premedication. Whether this lessening of the acute drop in the heart rate and increase in blood pressure typically seen during intubation of unmedicated infants is associated with long term advantages to the infants remains to be determined.

Body position, sleep states, and cardiorespiratory activity in developing low birth weight infants

The objective of this study was to determine the effects of body position (supine vs prone) on cardiorespiratory activity during quiet and active sleep in growing low birth weight (LBW) infants. The effect of postconceptional age on cardiorespiratory activity in the two positions was also evaluated. Fifty-one healthy, growing, appropriate for gestational age LBW infants (795-1600 g), ranging from 26-37 weeks in gestational age, were evaluated. All subjects were enrolled in an ongoing study of the effects of quality of dietary energy on the rate and composition of weight gain. Infants were randomly assigned to the supine or prone position for the first 3 h of the 6-h studies; the position was reversed for the second 3 h. Continuous recordings of cardiorespiratory activity were performed along with simultaneous minute by minute assignment of behavioral sleep state. Measurements of heart rate (HR), heart period variability (RR-SD), respiratory rate (f), and respiratory variability (fSD) were made each minute. Low birth weight infants had higher HR and f and lower RR-SD and fSD in the prone position compared to the supine position, during both quiet and active sleep. With increasing postconceptional age, positional differences in HR increased during quiet sleep and differences in RR-SD increased during both sleep states. These data demonstrate systematic differences in cardiorespiratory control related to body position during sleep. We speculate that such positional differences are due to variations in autonomic control, and may, in turn, contribute to variations in susceptibility to sudden infant death syndrome.

Maturational changes in heart rate and heart rate variability in low birth weight infants

To provide insight into the maturation of neural mechanisms responsible for variability in heart rate during quiet and active sleep, 6-hour continuous electrocardiographic recordings and simultaneous minute-by-minute behavioral activity state assignments were performed in 61 healthy, growing low birth weight infants. The infants weighed 795-1600 g at birth and ranged between 31-38 weeks in postconceptional age. During this age interval there was a decrease in heart rate during quiet sleep and an increase in both time domain and frequency domain measures of the variability in cardiac interbeat intervals. In quiet sleep, global variability, measured as SD of R-R intervals, increased in relation to age, as did higher frequency variability, measured as the square root of the mean of squared successive differences in R-R intervals. Developmental changes in the 0.5-2.0 Hz spectral power band of RR-interval variability, another measure of high frequency variability, paralleled the changes seen in the time domain measure. Evaluation of patterns of changes in the magnitude and direction of successive interbeat intervals provided evidence that the incidence of sustained accelerations or decelerations increased whereas the incidence of no change in consecutive RR-intervals decreased as infants matured. Among the various measures of heart rate variability, the incidence of sustained change and no change in successive interbeat intervals were most closely related to postconceptional age in both sleep states. The overall decrease in heart rate, increase in heart rate variability, and increase in the pattern of changes in interbeat interval with postconceptional age are consistent with the maturation of the autonomic cardio-regulatory activity from 31-38 weeks age.

Electroencephalographic activity of preterm infants is increased by Family Nurture Intervention: A randomized controlled trial in the NICU

OBJECTIVE To assess the impact of Family Nurture Intervention (FNI) on electroencephalogram (EEG) activity in preterm infants (26-34 weeks gestation). METHODS Two groups were tested in a single, level IV neonatal intensive care unit (NICU; standard care or standard care plus FNI) using a randomized controlled trial design. The intervention consists of sessions designed to achieve mutual calm and promote communication of affect between infants and their mothers throughout the NICU stay. EEG recordings were obtained from 134 infants during sleep at ∼35 and ∼40 weeks postmenstrual age (PMA). Regional brain activity (power) was computed for 10 frequency bands between 1 and 48 Hz in each of 125 electrodes. RESULTS Near to term age, compared to standard care infants, FNI infants showed robust increases in EEG power in the frontal polar region at frequencies 10 to 48 Hz (20% to 36% with p-values <0.0004). Effects were significant in both quiet and active sleep, regardless of gender, singleton-twin status, gestational age (26-30 or 30-35 weeks) or birth weight (<1500 or >1500 g). CONCLUSION FNI leads to increased frontal brain activity during sleep, which other investigators find predictive of better neurobehavioral outcomes. SIGNIFICANCE FNI may be a practicable means of improving outcomes in preterm infants.

Motion resistant pulse oximetry in neonates

Background: Pulse oximetry is widely used in neonates. However, its reliability is often affected by motion artefact. Clinicians confronted with questionable oxygen saturation (Spo2) values often estimate the reliability by correlating heart rate (HR) obtained with the oximeter with that obtained by electrocardiogram. Objective: To compare the effects of motion on Spo2 and HR measurements made with Masimo signal extraction technology and those made with a Nellcor N-200. Design: Continuous pulse oximetry and HR monitoring were performed in 15 healthy, term infants (mean (SD) birth weight 3408 (458) g) undergoing circumcision, using Masimo and Nellcor pulse oximeters and a standard HR monitor (Hewlett-Packard). Simultaneous minute by minute behavioural activity codes were also assigned. Baseline data were collected for 10 minutes when the infant was quietly asleep and then continued during and after circumcision for a total duration of one hour. The oximeter HR and Spo2 values were compared and related to HR values obtained by ECG during all three periods. The effect of behavioural activity on Spo2 and HR was also evaluated. Results: When compared with results obtained with the Nellcor, the mean Spo2 and HR were higher and the incidence of artefact lower with the Masimo during all three periods. Masimo HR more accurately predicted HR obtained with a standard monitor, with lower residual error. Spo2 and HR values obtained with the Nellcor were lower and more variable during all behavioural states, especially crying, when excessive motion artefact was most likely. Conclusions: The data suggest that Masimo signal extraction technology may offer improvement in pulse oximetry performance, particularly in clinical situations in which extreme motion artefacts are likely.

Is the New Definition of Bronchopulmonary Dysplasia More Useful

OBJECTIVE:To determine the incidence of bronchopulmonary dysplasia (BPD) in low birth weight (LBW) infants <1251 g managed with early bubble nasal continuous positive airway pressure (NCPAP) and a gentle ventilation strategy using the newly proposed definition for BPD and the previous definitions.METHODS:Needs for supplemental oxygen and positive pressure (positive pressure ventilation or NCPAP) during initial hospitalization were evaluated in 266 inborn LBW infants (birth weight <1251 g). The data were categorized in three weight groups, <751, 751 to 1000 and 1001 to 1250 g and the incidence of BPD was computed in survivors based on oxygen need at 28 days, 36 weeks postmenstrual age (PMA) and the new severity of BPD criteria, that is, mild BPD: need for supplemental oxygen ≥28 days, but not at 36 weeks PMA; moderate BPD: need for supplemental oxygen ≥28 days and <30% at 36 weeks PMA and severe BPD: need for supplemental oxygen ≥28 days, and >30% at 36 weeks PMA and/or positive pressure at 36 weeks PMA. Further, BPD-associated comorbidities and short-term outcome data during hospitalization were compared among the groups, defined by severity of BPD.RESULTS:Among LBW infants <1251 g, the incidences of BPD at 28 days and 36 weeks PMA were 21.1 and 7.4% respectively. Using the newly defined criteria, the incidences of mild, moderate and severe BPD were 13.5, 4.8 and 2.6%, respectively. In total, 64.6% of these infants had mild BPD and 70.8% weighed <751 g at birth. Associated comorbidities correlated significantly with grades of underlying pulmonary disease. Also, significantly longer hospital stay, discharge at a higher PMA and lower growth velocity was observed with increasing grades of BPD.CONCLUSIONS:The new system for grading the severity of BPD offers a better description of underlying pulmonary disease and correlates with the infants maturity, growth and overall severity of illness. Whether it will have a role in predicting long-term outcome remains to be determined.

Effects of body position on thermal, cardiorespiratory and metabolic activity in low birth weight infants

BACKGROUND Low birth weight (LBW) infants sleeping prone are known to exhibit many physiological differences from those sleeping supine, including lower energy expenditure (heat production) and higher surface temperature. This apparent increase in heat storage suggests that heat loss may be inhibited in the prone position which, in turn, might influence cardiorespiratory activity. AIMS To determine the effects of body position (prone vs. supine) on absolute surface temperature profile (heat storage), central-peripheral (C-P) thermal gradients (vasomotor response), cardiorespiratory activity and metabolic gas exchange in growing LBW infants. METHODS Six-hour continuous recordings of absolute surface temperature profiles, cardiorespiratory activity and O2 and CO2 exchange, along with minute-to-minute assessment of behavioral sleep states were performed in 32 healthy growing LBW infants (birth weight 805-1590 g, gestational age 26-35 weeks and postconceptional age at study 33-38 weeks). Each infant was randomly assigned to the prone or supine position for the first 3 h of the study and then reversed for the second 3 h. Surface temperatures were recorded from 4 sites (forehead, flank, forearm and leg) and averaged each minute. Central (forehead and flank)-to-peripheral (forearm and leg) and forehead-to-environment (H-E) thermal gradients were calculated from the surface temperatures. Corresponding sleep states were aligned with minute averages obtained from the temperature and cardiorespiratory measurements. Data were then sorted for prone and supine positions during quiet (QS) and active sleep (AS) and compared using paired t-tests. RESULTS In the prone position during both AS and QS, infants had higher forehead, flank, forearm and leg surface temperatures, narrower C-P gradients, higher heart rates and respiratory frequency, and lower heart rate and respiratory variability. Despite similar environmental temperatures, the H-E gradient was higher in the prone position. In the prone position infants demonstrated lower O2 consumption and CO2 production and a higher respiratory quotient. CONCLUSIONS Despite thermoregulatory adjustments in cardiorespiratory function, infants sleeping prone have relatively higher body temperature. The cardiorespiratory responses to this modest increase in temperature indicate that thermal and metabolic control of cardiac and respiratory pumps seem to work in opposition. The consequences of any attendant changes in blood gas activity (e.g. hypocapnia and/or increased mixed venous oxygen concentration) due to this override of metabolic control remains speculative.

Inhaled nitric oxide and gentle ventilation in the treatment of pulmonary hypertension of the newborn: a single-center, 5-year experience

OBJECTIVE: To evaluate the effect of inhaled nitric oxide (INO) in pulmonary hypertension of the newborn (PH) in a single center over 5 years using gentle ventilation (GV), without hyperventilation or induced alkalosis.METHODS: Data from 229 consecutive infants with PH of varied etiology treated with INO and GV, and from 67 infants with meconium aspiration syndrome (MAS) and primary PH (PPHN) treated with GV alone were reviewed over a 5-year period (86% outborn). INO was initiated at 25 ppm when PH and severe hypoxemia persisted despite maximal optimal ventilation. Hyperventilation or systemic alkalosis were not attempted.RESULTS: Mean duration of ventilation was 9.9±14 days (median 6.5 days). Average mean airway pressure (MAP) dropped from 17.7±4.3 cm H2O at the referral hospital to 13.2±2.5 cm H2O (p<0.001) following admission to our unit using conventional settings and GV, before starting INO. Mean oxygenation index (OI) dropped from 46.8±24.5 to 22.7±21.4 within 24 hours of INO therapy (p<0.001). Infants with higher baseline pH and lower baseline OI responded better to INO (p<0.02). Overall survival was 72%. Patients with MAS and PPHN had the best response, 92% survived and there was a 46% reduction in need for extracorporeal membrane oxygenation (ECMO) compared to historical pre-INO period controls (23.9% vs. 12.8%, p<0.01). In the infants treated with GV alone, the MAP dropped from 17.2±4.3 cm H2O at the referral hospital to 12.6±2.4 after GV was started in our unit.CONCLUSIONS: We conclude that INO is an effective and well-tolerated therapy for PH in infants receiving GV.