Infant mortality in the United States.

The infant mortality rate (IMR) of 6.0 per 1000 live births in the United States in 2013 is nearly the highest among developed countries. Moreover, the IMR among blacks is >twice that among whites-11.11 versus 5.06 deaths per 1000 live births.This higher IMR and racial disparity in IMR is due to a higher preterm birth rate (11.4% of live births in 2013) and higher IMR among term infants. The United States also ranks near the bottom for maternal mortality and life expectancy among the developed nations-despite ranking highest in the proportion of gross national product spent on health care. This suggests that factors other than health care contribute to the higher IMR and racial disparity in IMR. One factor is disadvantaged socioeconomic status. All of the actionable determinates that negatively impact health-personal behavior, social factors, heath-care access and quality and the environment-disproportionately affect the poor. Addressing disadvantaged socioeconomic status by improving access to quality health care and increasing social expenditures would have the greatest impact on the USA's IMR and racial disparity in IMR.

Neonatal outcomes of fetuses diagnosed with life-limiting conditions when individualized comfort measures are proposed.

OBJECTIVE: To describe the neonatal outcomes of a case series of infants who were prenatally diagnosed with potential life-limiting conditions and to whom individualized comfort measures were offered. STUDY DESIGN: This is a retrospective analysis of the postnatal outcomes of a selected population of 49 infants prenatally diagnosed with potential life-limiting conditions whose parents were prenatally referred for counseling to the comfort care team. RESULT: The prenatal diagnosis was confirmed postnatally in 45 infants. The only four survivors had a significant discrepancy between prenatal and postnatal diagnosis. Whether they were treated with individualized comfort measures (n=28) or intensive care (n=17), all the newborns died with similar median age at death (2 days). CONCLUSION: Diagnostic accuracy is the main determinant of outcomes. Provision of intensive care neither prevents the death of infants affected by life-limiting conditions nor prolongs life compared with that of infants treated with individualized comfort measures.

Hypocapnia and other ventilation-related risk factors for cerebral palsy in low birth weight infants.

Ventilatory management patterns in very low birth weight newborns, particularly iatrogenic hypocapnia, have occasionally been implicated in perinatal brain damage. However, such relationships have not been explored in large representative populations. To examine the risk of disabling cerebral palsy in mechanically ventilated very low birth weight infants in relation to hypocapnia and other ventilation-related variables, we conducted a population-based prospective cohort study of 1105 newborns with birth weights of 500-2000 g born in New Jersey from mid-1984 through 1987, among whom 777 of 902 survivors (86%) had at least one neurodevelopmental assessment at age 2 y or older. Six hundred fifty-seven of 777 assessed survivors (85%), of whom 400 had been mechanically ventilated, had blood gases obtained during the neonatal period. Hypocapnia was defined as the highest quintile of cumulative exposure to arterial PCO(2) levels <35 mm Hg during the neonatal period. Disabling cerebral palsy was diagnosed in six of 257 unventilated newborns (2.3%), 30 of 320 ventilated newborns without hypocapnia (9.4%), and 22 of 80 ventilated newborns with hypocapnia (27.5%). Two additional ventilatory risk factors for disabling cerebral palsy were found-hyperoxia and prolonged duration of ventilation. In a multivariate analysis, each of the three ventilatory variables independently contributed a 2- to 3-fold increase in risk of disabling cerebral palsy. These risks were additive. Although duration of mechanical ventilation in very low birth weight newborns likely represents severity of illness, both hypocapnia and hyperoxia are largely controlled by ventilatory practice. Avoidance of arterial PCO(2) levels <35 mm Hg and arterial PO(2) levels >60 mm Hg in mechanically ventilated very low birth weight infants would seem prudent.

Comparison of management strategies for extreme prematurity in New Jersey and the Netherlands: outcomes and resource expenditure.

OBJECTIVE: To quantify differences in resource expenditure in the perinatal period and long-term outcome of extremely premature infants who received systematically different approaches to neonatal intensive care. METHODS: Perinatal management, mortality, prevalence of disabling cerebral palsy (DCP), and resource expenditure of 2 population-based inception cohorts of extremely premature infants born in the mid-1980s were compared. Electronic fetal monitoring, tocolysis, cesarean section delivery, and assisted ventilation were used to characterize management approaches. Participants included all live births at 23 to 26 weeks' gestation in a 3-county area of central New Jersey (NJ) from 1984 to 1987 (N = 146) and throughout the Netherlands (NETH) in 1983 (N = 142). Mortality and the prevalence of DCP were the primary outcomes. Numbers of hospital days with and without assisted ventilation were the measures of resource expenditure. RESULTS: Electronic fetal monitoring (100% vs 38%), cesarean section (28% vs 6%), and assisted ventilation (95% vs 64%) were all more commonly used in NJ than in NETH. Ten percent of NJ deaths occurred without assisted ventilation, compared with 45% of Dutch deaths. A total of 1820 ventilator days were expended per 100 live births in NJ, compared with 448 in NETH. The increase in the number of nonventilator days (3174 vs 2265 days per 100 live births) did not reach statistical significance. Survival to age 2 (46 vs 22%) and the prevalence of DCP among survivors (17.2 vs 3.4%) were significantly greater in NJ at age 2 than in NETH at age 5. CONCLUSIONS: Near universal initiation of intensive care in NJ, compared with selective initiation of intensive care in NETH, was associated with 24.1 additional survivors per 100 live births, 7.2 additional cases of DCP per 100 live births, and a cost of 1372 additional ventilator days per 100 live births.

The outcome of extreme prematurity.

Significant advances in perinatology and neonatology in the last decade have resulted in increased survival of extremely premature infants. Survival rates for infants born in tertiary perinatal and neonatal care centers in the United States in the 1990s increase with each week of gestational age from 22 through 26 weeks. Reported survival rates at 22 weeks range from 0% to 21% in the few reporting studies. Reported survival rates at 23 and 24 weeks range from 5% to 46% and from 40% to 59%, respectively. These may not be the maximum survival rates possible because at these gestational ages information is either insufficient to determine that obstetric and neonatal intensive care strategies to maximize neonatal survival were used or it is specified that such strategies were not used. Reported survival rates at 25 and 26 weeks range from 60% to 82% and from from 75% to 93%, respectively. The literature regarding the prevalence of major neurodevelopmental disabilities among extremely premature survivors in the last 25 years is heteogeneous, and the reported prevalances of major disability vary much more than do survival rates. However, the majority of extremely premature infants who survive will be free of major disability. Overall, approximately one fifth to one quarter of survivors have at least one major disability-impaired mental development, cerebral palsy, blindness, or deafness. Impaired mental development is the most prevalent disability (17%-21% [95% CI] of survivors affected), followed by cerebral palsy (12%-15% of survivors affected). Blindness and deafness are less common (5% to 8% and 3% to 5% of survivors affected, respectively). Approximately one half of disabled survivors have more than one major disability. Based on studies of infants less than 750 to 1,000 grams birth weight, it can be anticipated that approximately another half of all extremely premature survivors will have one or more subtle neurodevelopmental disabilities in the school and teenage years. There is little evidence to suggest that long-term neurodevelopmental outcome has changed from the late 1970s to the early 1990s or with increasing survival. Survival of individual extremely premature infants cannot be accurately predicted in the immediate perinatal period. Major disability cannot be accurately predicted for individual survivors during the course in the newborn intensive care unit.

Sonographic needle guidance in cholangiography in children.

PURPOSE: To evaluate feasibility and benefits of sonographic guidance of percutaneous transhepatic cholangiography (PTC) in children with liver transplants. MATERIALS AND METHODS: The authors prospectively followed 24 PTC procedures in 19 pediatric patients (11 females, 8 males; age 3 months to 17 years) randomized to fluoroscopic or sonographic guidance. The number of needle passes, the contrast material dose, fluoroscopy time, and procedure time for each procedure were recorded. All patients were transplant recipients-six whole and 13 reduced-size grafts. Cases were randomly assigned to two groups: group I, fluoroscopically guided PTC (12 procedures); group II, sonographically guided PTC (12 procedures). RESULTS: The technical success rate was 92% (11 of 12) for each group. In group I, there were two procedure-related complications: postprocedural fever caused by biliary to portal vein fistula, and peritoneal bleeding requiring surgery. In group II, there were no procedure-related complications. A mean of 8.2 +/- 3.7 needle passes were required in group I compared to only 2.0 +/- 1.3 in group II (P < .0001). A mean contrast material dose of 19.5 mL +/- 13.4 was required in group I compared to only 2.5 mL +/- 1.9 in group II (P < .001). A mean procedure time of 15.7 minutes +/- 7.4 was required in group I compared to only 6.1 minutes +/- 4.5 in group II (P < .001). A mean fluoroscopy time of 10.4 minutes +/- 5.0 was required in group I compared to only 1.0 minutes +/- 0.7 in group II (P < .0001). CONCLUSION: In pediatric patients who have undergone liver transplantation, sonographic guidance significantly decreases the number of needle passes, contrast material dose, and fluoroscopy time required for PTC.

Radiologic placement of implantable chest ports in pediatric patients.

OBJECTIVE: We evaluated the technical success and complications associated with radiologic placement of implantable chest ports in children for long-term central venous access. MATERIALS AND METHODS: Between May 1, 1996 and January 11, 2000, 29 chest ports were placed in 28 children (15 girls, 13 boys; age range, 2-17 years; mean, 11.7 years). The patient's right internal jugular vein was used for access in 93% (27/29) of the procedures, and a collateral neck vein was used as a conduit to recanalize the central veins in two procedures because of bilateral jugular and subclavian vein occlusion. All procedures were performed in interventional radiology suites. Both real-time sonography and fluoroscopy were used to guide venipuncture and port insertion. Follow-up data were obtained through the clinical examination and electronic review of charts. RESULTS: Technical success was 100%. Fourteen percent of the catheters were removed prematurely, including one catheter removed 17 days after placement because the patient's blood cultures were positive for Candida albicans. No patients experienced hematoma, symptomatic air embolism, symptomatic central venous thrombosis, catheter malposition, or pneumothorax. The median number of days for catheter use by patients was 280 days (total, 9043 days; range, 17-869 days). The rate of confirmed catheter-related infection was 14% or 0.04 per 100 venous access days. One catheter occluded after 132 days. CONCLUSION: In pediatric patients, radiologists can insert implantable chest ports using real-time sonographic and fluoroscopic guidance with high rates of technical success and low rates of complication.

Percutaneous transhepatic cholangiography and biliary drainage in pediatric liver transplant patients.

OBJECTIVE: In children with liver transplants, percutaneous transhepatic cholangiography has a critical role in evaluation and treatment of biliary complications. The purpose of this study was to evaluate the technical success and complication rates of percutaneous transhepatic cholangiography and biliary drain placement in children who underwent liver transplantation. MATERIALS AND METHODS: Between January 1, 1995 and July 1, 1999, 120 pediatric percutaneous transhepatic cholangiography procedures were performed in 76 patients (34 boys, 42 girls; age range, 5 months to 18 years; mean age, 5.3 years). Patients had received left lateral segment, whole-liver, or split-liver transplant grafts. Retrospective review of all pertinent radiology studies and electronic chart review were performed. RESULTS: A diagnostic cholangiogram was obtained in 96% (115/120) of all procedures and drainage catheter placement was successful in 89% (88/99) of attempts. In patients with nondilated intrahepatic bile ducts, a diagnostic cholangiogram was obtained in 92% (46/50) of procedures, and drainage catheter placement was successful in 76% (19/25) of attempts. Minor complications occurred in 10.8% (13/120) of procedures and included transient hemobilia with mild drop in hematocrit level (n = 2), mild pancreatitis (n = 1), fever with bacteremia (n = 5), and fever with negative blood cultures (n = 5). Major complications occurred in 1.7% (2/120) of procedures and included sepsis (n = 1) and hemoperitoneum requiring immediate surgery (n = 1). CONCLUSION: Percutaneous transhepatic cholangiography and biliary drainage can be performed with high technical success and low complication rates in pediatric liver transplant patients, even in those with nondilated intrahepatic ducts.

Survival of the extremely preterm infant in North America in the 1990s.

Survival of extremely premature infants has been significantly higher in the last decade than previously, and may well have improved during this time. The majority of infants greater than or equal to 25 weeks' gestation survive today. Survival of infants 23 and 24 weeks' gestation is significantly lower, but is by no means negligible. Reports of survival of infants less than 23 weeks or less than 500-g birth weight are not unique. Moreover, the maximum survival of infants less than or equal to 25 weeks possible with current state-of-the-art care is not known. Currently available data do not allow survival of the individual extremely low-birth weight or extremely premature infant to be predicted with clinically acceptable accuracy. The concept of a limit of viability is vague and clinically and ethically simplistic. The provision of neonatal intensive care is not necessarily beneficial or justified merely because it affords some minimal chance of survival. This phrase should not be used to summarize the complex issues involved in balancing maternal and neonatal risks and benefits of intrapartum and neonatal care of the extremely low-birth weight or the extremely premature fetus and infant, the suffering of the infant and family, parental values and autonomy, and consumption of limited communal resources. It should be deleted from our vocabulary.

Serum anion gap in the differential diagnosis of metabolic acidosis in critically ill newborns.

OBJECTIVES: To determine in critically ill newborn infants (1) the range of the serum anion gap without metabolic acidosis and (2) whether the serum anion gap can be used to distinguish newborns with lactic acidosis from those with hyperchloremic metabolic acidosis. STUDY DESIGN: Umbilical arterial blood gases and serum electrolyte and lactate concentrations were measured simultaneously in 210 samples from 63 infants over the first week of life. Metabolic acidosis was defined as a blood base deficit (BD) >4 mmol/L. The anion gap was calculated as [Na(+)] - [C1(-)] - [TCO (2)]. Lactic acidosis was defined as a serum lactate concentration >2 SD above the mean serum lactate concentration in samples without metabolic acidosis. RESULTS: In 89 blood samples with BD <4 mmol/L, serum lactate concentration decreased with postnatal age (r = 0.51). The upper limit of serum lactate concentration was 3.8 mmol/L at less than 48 hours, 2.4 mmol/L between 48 and 96 hours, and 1.5 mmol/L for infants greater than 96 hours of age. The mean serum anion gap +/- 2 SD in 174 samples without lactic acidosis was 8 +/- 4 mmol/L; in 36 samples with lactic acidosis it was 16 +/- 9 mmol/L (P <.0001). Serum anion gap and lactate concentration were poorly correlated for samples without lactic acidosis (r = 0.04) but highly correlated in those with lactic acidosis (r = 0.81, P <.0001). None of the 85 samples with metabolic acidosis but without lactic acidosis had an anion gap >16 mmol/L; only 4 of 36 samples with lactic acidosis had an anion gap <8 meq/L. However, 25 of 36 samples with lactic acidosis had serum anion gaps of 8 to 16 mmol/L. CONCLUSION: In the presence of metabolic acidosis, a serum anion gap >16 mmol/L is highly predictive of lactic acidosis; a serum anion gap <8 is highly predictive of the absence of lactic acidosis; an anion gap = 8 - 16 mmol/L has no use in the differential diagnosis of metabolic acidosis in the critically ill newborn.

Exchange of poorly functioning tunneled permanent hemodialysis catheters.

OBJECTIVE: The usefulness of exchanging poorly functioning tunneled permanent hemodialysis catheters in patients with end-stage renal disease was evaluated. MATERIALS AND METHODS: We retrospectively reviewed case histories of 51 consecutive patients who underwent 88 catheter exchanges because of poor flow rates. All hemodialysis catheters were initially placed by the radiology service using image guidance. Catheter exchanges were performed through the existing subcutaneous tract over two stiff hydrophilic guidewires and without additional interventions such as fibrin sheath stripping or venoplasty. Life table analysis was performed to evaluate catheter patency rates after initial placement (primary patency) and after multiple exchanges (secondary patency). RESULTS: The technical success rate for hemodialysis catheter exchange was 100%. Primary catheter patency was 42% at 60 days and 16% at 120 days. Secondary patency was 92% at 60 days and 82% at 120 days. The cumulative infection rate was 1.1 per 1000 catheter days. No complications from the procedure occurred. CONCLUSION: Catheter exchange is an effective means of prolonging catheter patency in patients with end-stage renal disease and limited central venous access.

Angioplasty and bolus urokinase infusion for the restoration of function in thrombosed Brescia-Cimino dialysis fistulas.

PURPOSE: To evaluate the use of urokinase and angioplasty in treatment of thrombosed Brescia-Cimino fistulas. MATERIALS AND METHODS: From January 1994 to April 1997, 17 patients (10 women and seven men; age range, 17-78 years; mean 54 years) with complete thrombosis of their Brescia-Cimino fistulas were referred to our department for thrombolysis and angioplasty. Thrombosis of the fistula had occurred within 24 hours of attempted thrombolysis in 11 patients and between 24 and 72 hours in six patients. Urokinase was given as a bolus into the fistula, and heparin was administered into the central venous vasculature. Angioplasty was performed at the arterial inflow and the fistula itself. RESULTS: Procedural success was 82% (14 of 17 patients). Primary patency was 71% at 6 months and 64% at 12 months. Primary assisted patency was 93% at 6 and 12 months. Secondary patency was 100% at 6 and 12 months. One fistula thrombosed within 24 hours of the initial procedure, and a repeat procedure was successfully performed. All other fistulas have remained patent with a maximum follow-up of 40 months (average function of 16 months). Two patients have died of unrelated causes. One Wallstent was deployed for treatment of an angioplasty-induced venous rupture. CONCLUSION: Long-term function of Brescia-Cimino fistulas after thrombolysis and angioplasty is excellent with patency rates similar to those of newly placed, mature Brescia-Cimino fistulas.

Experience with tunneled femoral hemodialysis catheters.

OBJECTIVE: The purpose of this study was to evaluate the use and complication rate of tunneled femoral hemodialysis catheters placed in patients with no remaining thoracic venous access sites. MATERIALS AND METHODS: Over a 3-year period, 41 tunneled femoral vein catheters (35 right, six left) were placed in 21 patients (15 women, six men; 21-89 years old; mean, 52 years). Catheters ranged in length from 40 to 60 cm. Tips were positioned immediately above the iliac bifurcation, at the mid inferior vena cava (IVC), or at the junction of the IVC and right atrium. Catheters were exchanged through the existing tract if the flow rate decreased to less than 200 ml/min. Catheters were removed if an episode of bacteremia did not resolve with antibiotics or if the insertion site became infected. RESULTS: Technical success of placement was 100%. The 30-, 60-, and 180-day primary patency rates were 78%, 71%, and 55%, respectively. The 30-, 60-, and 180-day secondary patency rates were 95%, 83%, and 61%, respectively. Average time of function per intervention was 61 days. Infections requiring catheter removal occurred at a rate of 2.4 per 1000 catheter days. One episode of partial IVC thrombosis occurred after a catheter infection developed 78 days after initial catheter placement. No episodes of symptomatic pulmonary embolism occurred. Total length of follow-up was 2506 catheter days. CONCLUSION: Femoral vein catheters require more frequent interventions than do thoracic catheters and are more susceptible to infection. However, in patients with difficult central venous access, the common femoral vein may be successfully used for permanent tunneled hemodialysis access.

A quantitative review of mortality and developmental disability in extremely premature newborns.

OBJECTIVES: To summarize the literature on mortality rates and prevalences of major neurodevelopmental disabilities and to examine trends of these outcomes over time in extremely premature neonates. DATA SOURCES: MEDLINE was used to search the English literature for studies published since 1970 reporting on both mortality and disability in infants born at or before 26 weeks' gestation (extremely immature [EI] cohort), with a birth weight of 800 g or less (extremely small [ES] cohort), or subgroups of these. STUDY SELECTION: Studies were included in the analysis if all of the following were reported: mortality; direct examination of 75% or more of the survivors; and the proportion of patients with at least 1 of the following disabilities: cerebral palsy, mental retardation, blindness, and deafness. Studies reporting cohorts included as a subset of cohorts in another study were excluded. Forty-two studies providing mortality and disability data for 20 cohorts of 4116 EI infants and 38 cohorts of 4345 ES infants born after 1972 met the inclusion criteria. DATA EXTRACTION: Data were abstracted from all studies that met these criteria by two of us (J.M.L. and D.E.W.), independently; the data were then cross-checked to ensure accuracy. RESULTS: Survival averaged 41% for EI infants and 30% for ES infants, and it increased significantly with time. In contrast to mortality, the prevalences of major neurodevelopmental disabilities among survivors have not changed over time. The most common major disability was mental retardation, found in 14% of EI and ES survivors. Cerebral palsy was found in 12% of EI survivors and 8% of ES survivors, blindness was found in 8% of EI and ES survivors, and deafness was found in 3% of EI and ES survivors. Overall, 22% of EI survivors and 24% of ES survivors were classified as having at least 1 major disability. Each 100 EI or ES livebirths yielded 7 children with major disabilities; this prevalence was correlated with survival across cohorts. CONCLUSIONS: The prevalence of disabilities had not changed among EI or ES survivors with increasing survival. However, increasing survival of these infants has resulted in a steadily increasing prevalence of children with disabilities.

Potassium metabolism in extremely low birth weight infants in the first week of life.

OBJECTIVE: Nonoliguric hyperkalemia has been reported to occur in the first week of life in as many as 50% of extremely low birth weight (ELBW) infants. We studied potassium balance and renal function in the first 5 days of life to characterize potassium metabolism during the three phases of fluid and electrolyte homeostasis that we have described in ELBW infants and to elucidate the factors that contribute to the development of nonoliguric hyperkalemia. STUDY DESIGN: Plasma potassium concentration (PK), potassium intake and output, and renal clearances were obtained for the first 6 days of life in 31 infants with a birth weight of 1000 gm or less. Collection periods in which urine flow rate was greater than or equal to 3 ml/kg per hour and weight loss was greater than or equal to 0.8 gm/kg per hour were denoted to be diuretic. Prediuresis includes all collection periods before the first diuretic period; diuresis includes all collection periods between the first and last diuretic periods; postdiuresis includes all collection periods after the last diuretic period. Infants with a PK greater than 6.7 mmol/L on at least one measurement were denoted to have hyperkalemia. RESULTS: PK increased initially after birth--despite the absence of potassium intake- and then decreased and stabilized by the fourth day of life. Diuresis occurred in 27 of 31 infants. The age at which PK peaked was closely related to the onset of diuresis. PK decreased significantly during diuresis as the result of a more negative potassium balance, despite a significant increase in potassium intake. In fact, PK fell to less than 4 mmol/L in 13 of 27 infants during diuresis. After the cessation of diuresis, potassium excretion decreased even though there was a significant increase in potassium intake, potassium balance was zero, and PK stabilized. Hyperkalemia developed in 11 of 31 infants. The pattern of change in PK with age was similar in infants with normokalemia and hyperkalemia: PK initially increased (essentially in the absence of potassium intake) and then decreased and stabilized by the fourth day of life. However, the rise in PK after birth was greater in infants with hyperkalemia than in those with normokalemia: 0.7 +/- 0.2 versus 1.8 +/- 0.2 mmol/L (p < 0.001). No differences in fluid and electrolyte homeostasis or renal function were identified as associated with hyperkalemia. CONCLUSIONS: PK increases in most ELBW infants in the first few days after birth as a result of a shift of potassium from the intracellular to the extracellular compartment. The increase in the glomerular filtration rate and in the fractional excretion of sodium, with the onset of diuresis, facilitates potassium excretion, and PK almost invariably decreases. Hyperkalemia seems to be principally the result of a greater intracellular to extracellular potassium shift immediately after birth in some ELBW infants.

A standard protocol for blood pressure measurement in the newborn.

OBJECTIVES: Improvements in neonatal care have resulted in increasing survival of extremely premature infants whose hospital course often runs into weeks or months. Some interventions during the acute care of these neonates, such as umbilical catheterization and use of steroids, not infrequently result in elevation of blood pressure (BP). It is, therefore, essential that these infants be monitored accurately for possible hypertension during their convalescence. Unfortunately, normative data on BP in this population are scant and comparison of data from various studies is hampered by methodologic differences in design. Studies in adults address the necessity for a restful state, adopting a comfortable position, and attempts to reduce the startle response to initial cuff inflation. Studies in the newborn using the oscillometric technique have not addressed these concerns. A standard BP measurement protocol was studied to determine the effect of ensuring a restful state, startle response to cuff inflation, and infant position on BP in clinically stable low birth weight infants after the first week of life. STUDY DESIGN: The Dianamap oscillometer was used to measure BP in infants with a birth weight <2500 g between 7 and 42 days postnatal age. Each infant was studied only once when they were clinically stable. BP was measured in two positions, prone and supine, in random order. Infants were studied at least 11/2 hours after their last feeding or medical intervention. An appropriate sized cuff was applied to the right upper arm and the infant was positioned according to randomization. The infant was then left undisturbed for at least 15 minutes or until the infant was sleeping or in a quiet awake state. Three successive BP recordings were taken at 2-minute intervals. The infant's position was then reversed and another 15 minutes of quiet time was allowed. Thereafter, a second set of three successive BP recordings were obtained. The most recent routine nursing BP measurement was also recorded. Data were analyzed using analysis of variance and are presented as means and standard errors of the mean. RESULTS: Sixty-four infants were studied. Birth weights ranged from 901 to 2423 g and gestational ages from 26 to 37 weeks. Overall, mean BP was significantly lower in the prone than supine positions (45.7 +/- 0.7 vs 47.8 +/- 0.8 mm Hg, P < .002). In either position, the first measurement was significantly higher than the third (average difference was 3 mm Hg, P < .003). In general, the relationships among position and order of measurement were similar for systolic and diastolic BP. Mean BPs obtained by routine nurse measurements were significantly higher than those in either position using our standard protocol (54.4 vs 47.0 or 49.1 mm Hg, P < .003). Moreover, the routine nurse measurements varied more widely than did those obtained using the standard protocol. The standard deviation for the routine mean BP measurements by nurses was 11.4 compared with 6.8 and 8.2 for the first measurements in the prone and supine positions, respectively, with the standard protocol. The mean BP measurements made in the supine position (the highest measurements obtained) using the standard protocol were also significantly lower than published values: 57 of 64 measurements were less than the average mean BP for age described by Tan (J Pediatr. 1988; 112:266-270). CONCLUSION: The statistically significant difference between the prone and supine position and among successive measurements in each position are not clinically relevant. The clinically significant differences between measurements obtained with this standard protocol and routine nursing measurements or published data are the result of ensuring a restful state after cuff application. We believe that measurements thus obtained are more representative of true resting BPs in these infants. (ABSTRACT TRUNCATED)