Vivek Ghai

Mode of delivery and risk of respiratory diseases in newborns

Objective To determine whether there is an increased incidence of persistent pulmonary hypertension in neonates delivered by cesarean, with or without labor, compared with those delivered vaginally. Methods We did a computerized retrospective review of 29,669 consecutive deliveries over 7 years (1992–1999). The incidences of persistent pulmonary hypertension of the newborn, transient tachypnea of the newborn, and respiratory distress syndrome (RDS) were tabulated for each delivery mode. Cases of persistent pulmonary hypertension were reviewed individually to determine delivery method and whether labor had occurred. The three groups defined were all cesarean deliveries, all elective cesareans, and all vaginal deliveries. Results Among 4301 cesareans done, 17 neonates had persistent pulmonary hypertension (four per 1000 live births). Among 1889 elective cesarean deliveries, seven neonates had persistent pulmonary hypertension (3.7 per 1000 live births). Among 21,017 vaginal deliveries, 17 neonates had persistent pulmonary hypertension (0.8 per 1000 live births). χ2 analysis showed an odds ratio 4.6 and P < .001 for comparison of elective cesarean and vaginal delivery for that outcome. Conclusion The incidence of persistent pulmonary hypertension of the newborn was approximately 0.37% among neonates delivered by elective cesarean, almost fivefold higher than those delivered vaginally. The findings have implications for informed consent before cesarean and increased surveillance of neonates after cesarean.

MORBIDITY AND MORTALITY FACTORS IN TWINS: AN EPIDEMIOLOGIC APPROACH

Some epidemiologic characteristics of twin pregnancies and twin infants have been reviewed. We found that twins are prone to be born prematurely and have lower birth weights than their singleton counterparts after 30 to 34 weeks of gestation. Twins are also more prone to birth asphyxia, hyaline membrane disease, respiratory disorders, and seizures. Congenital anomalies and nonrespiratory morbidity were not found to be increased in twins. Twins have a six times higher perinatal mortality rate than do singletons. This is accounted for by prematurity in the main. A part of the excess mortality in twins is accounted for by a higher mortality in larger, near-term twins. Efforts should be directed toward decreasing the incidence of prematurity in twins and understanding and managing the problems of near-term twins better.

Pediatrician attendance at cesarean delivery: necessary or not?

OBJECTIVE To determine whether it is necessary for a pediatrician to attend all cesarean deliveries. METHODS We analyzed a database of 17,867 consecutive deliveries to determine the rates of low Apgar scores in the following three groups of patients: those with vaginal delivery, cesarean delivery using regional anesthesia without fetal indication, and cesarean delivery for fetal indications or using general anesthesia. RESULTS There was a significantly higher rate of low Apgar scores in the fetal indications or general anesthesia group when compared with vaginal deliveries. Specifically, 35 (5.8%) of 596 cesareans for fetal heart rate abnormality or using general anesthesia had 1-minute Apgars under 4 in contrast to 115 of 10,270 (1.1%) of vaginal deliveries. There was no significantly increased risk for low Apgar scores in the group of cesareans using regional anesthesia for nonfetal indications (33 of 2057, 1.6%). Results were similar for Apgar scores under 7 at 5 minutes. CONCLUSION Because there is no higher incidence of low Apgar scores in cesarean deliveries using regional anesthesia for nonfetal indications compared with vaginal deliveries, there is no convincing need for pediatrician attendance at such deliveries.

IMPROVEMENT IN OXYGEN TENSIONS AND PULMONARY BLOOD FLOW WITH INTERMITTENT DISTAL AORTIC COMPRESSION DURING NORMOXIA, HYPOXIC HYPOXIA, AND HYPEROXIA IN NEONATAL PIGLETS

Background and MethodsWe investigated the hypothesis that, in a newborn piglet during normoxia, hypoxia, and hyperoxia, increasing aortic pressure transiently by intermittent short-duration aortic compression would affect left-to-right shunting of blood and thus increase pulmonary artery blood flow, pulmonary arterial Po2, and aortic Po2 proximal to the point of compression. We also investigated whether a balloon atrial septostomy, by providing an open channel for communication between the right- and left-sided circulations, would further improve pulmonary blood flow and aortic Po2.Studies were performed in eight 7− to 10-day-old newborn piglets in three phases (Fio2 of 0.21, 0.12, and 1.0) before and after balloon atrial septostomy in each piglet. Blood gas measurements and hemodynamic variables were recorded before and at the end of a 30-sec period of aortic compression. ResultsDuring aortic compression, all the animals demonstrated a 50 to 70 mm Hg increase in aortic pressure proximal to the compression. Before balloon septostomy, there were 21%, 41%, and 8% increases in aortic Po2 in the room air, hypoxic, and hyperoxic phases of the experiment, respectively. There were also statistically significant increments in pulmonary blood flow and arterial pressures. After balloon septostomy, there were 35%, 25%, and 21% increments in aortic Po2 during the room air, hypoxic, and hyperoxic phases of the experiment, respectively. However, there was no statistically significant further improvement in the effects of aortic compression on Po2 with septostomy compared with those effects before septostomy. CoclusionsOur results suggest that increasing systemic arterial pressures in order to forcibly affect left-to-right shunting of blood may be potentially beneficial in the management of hypoxia in situations where low pulmonary artery blood flow may be contributing to hypoxia, e.g., in persistent pulmonary hypertension of the newborn. (Crit Care Med 1991; 19:736)

Surfactant: Its Role in the Therapy of Respiratory Distress Syndrome

Over the past 2 decades major gains have been made in the area of the management of hyaline membrane disease [1–3]. Surfactant replacement therapy is probably the most exciting therapeutic milestone. It is expected that the introduction of this therapy will alleviate many of the complications associated with the classic therapeutic measures. Although surfactant is yet to be released for clinical use, this chapter summarizes the available literature and presents the results to the reader.