Effect of nasolacrimal occlusion on timolol concentrations in the aqueous humor of the human eye

We studied the effect of manual nasolacrimal occlusion on the concentration of timolol in the aqueous humor of eyes of patients undergoing cataract extraction. Aqueous humor samples were obtained at various times after timolol maleate instillation from patients with or without 5 min of nasolacrimal occlusion; aliquots were assayed by HPLC. In patients receiving occlusion treatment, average timolol concentrations were statistically greater than those in control patients both between 15 and 90 min after instillation and also at 180 min. Pharmacokinetic analysis indicated that occlusion increased the concentration of timolol in the aqueous humor 1.7 times. In both groups, timolol concentrations were highest approximately 1 h after instillation. The decline in aqueous humor timolol concentrations occurred at similar rates in both groups.

Eradication of Helicobacter mustelae from the ferret stomach: an animal model of Helicobacter (Campylobacter) pylori chemotherapy

Colonization of the ferret stomach by Helicobacter mustelae has been suggested as a possible animal model for Helicobacter pylori-associated gastroduodenal disease of humans. Our study was designed to determine whether antimicrobial chemotherapy could eradicate H. mustelae from ferrets. Triple antimicrobial therapy combining amoxicillin, metronidazole, and bismuth subsalicylate was successful in eradicating the organism from 5 of 7 (71%) adult ferrets. Despite apparent in vitro susceptibility, neither chloramphenicol monotherapy nor a polytherapeutic regimen combining tetracycline, metronidazole, and bismuth subsalicylate proved effective in the eradication of H. mustelae. Several strains isolated after unsuccessful polytherapy showed markedly increased resistance to metronidazole. These preliminary findings are similar to results of H. pylori treatment trials with humans and suggest that the ferret may be a useful model for evaluating and comparing potential antimicrobial modalities for the eradication of H. pylori.

Oxygenation index in patients with meconium aspiration: conventional and extracorporeal membrane oxygenation therapy

The use of the alveolar-arterial oxygen difference P(A-a)O2 and the oxygenation index (mean airway pressure [Paw] FIO2 x 100/PaO2) have been proposed for selecting infants who will require extracorporeal membrane oxygenation (ECMO) therapy. However, the use of the oxygenation index (OI) in conjunction with Paw in an exclusive population of patients with meconium aspiration syndrome (MAS) has not been reported. Fourteen patients born in our facility and managed with conventional therapy and five infants treated with ECMO were enrolled in the study. All patients had clinical and x-ray evidence of MAS. Infants who received conventional treatment required mechanical ventilation greater than 48 h, FIO2 1.0, and were under the care and supervision of one neonatologist. Management was directed to minimize barotrauma by avoidance of routine hyperventilation, use of lower Paw, and sufficient expiratory time. One patient died before ECMO and 13 infants survived. Six survivors had an OI greater than 25 (three had an OI greater than 40), six had a Paw greater than or equal to 12 cm H2O (12 to 15 cm H2O in five infants) and six patients had a P(A-a)O2 greater than or equal to 610 torr. One surviving infant was transferred for ECMO therapy (OI 67, Paw 20 cm H2O). The five patients treated with ECMO survived (OI 48 to 92, Paw 20 to 29.5 cm H2O P(A-a)O2 627 to 650 torr). One patient in each group developed chronic lung disease with evidence of resting tachypnea. Our findings indicate that an OI greater than 40 in association with a Paw greater than or equal to 20 cm H2O may be helpful in predicting which infants with MAS need ECMO, whereas patients requiring a Paw less than or equal to 15 cm H2O can be managed with conventional therapy. An OI greater than or equal to 25 but less than 40 is not associated with high mortality in these patients. The predictive value of Paw of 16 to 20 cm H2O and the duration of an OI greater than 40 in patients with MAS need further investigation.

Plasma amino acid concentrations in premature infants: effect of sampling site

Amino acid concentrations in plasma obtained from infants by heel puncture differ from those in venous plasma primarily because of skin contamination but data from the two sites might agree more closely in premature infants because of their poorly developed sweat glands. To evaluate the importance of sampling site, amino acids were analyzed by a sensitive high-performance liquid chromatographic method in plasma obtained both by heel puncture and venipuncture in 14 premature infants. Histidine, tryptophan, alanine, aspartic acid, glycine, and serine were higher in capillary plasma. Tryptophan and glycine levels in capillary plasma correlated strongly with those in venous plasma. An additional wash with soap and water done in five infants did not eradicate the differences. Thus the lack of agreement between data from the two sites may be due to factors other than contamination.

Diversity of serotypes of Campylobacter jejuni and Campylobacter coli isolated in laboratory animals

One hundred nineteen isolates of Campylobacter jejuni and Campylobacter coli from nine laboratory animal species were serotyped using antisera to 20 Penner serotypes commonly isolated from cases of human enteric infections. Although C. jejuni and C. coli were isolated from laboratory animals with diarrhea, the majority were cultured from asymptomatic animals (81%). Seven of twenty-two isolates from animals with diarrhea were serotype 4 (32%) and three were serotype 1 (14%). Sixty-one of the 119 isolates (51%) were typeable using the 20 Penner antisera indicating that many of the isolates obtained from 29 nonhuman primates (five species), 20 ferrets, 7 hamsters, 15 cats and 48 dogs are serotypes commonly associated with human enteritis. Among typeable strains, 13 different serotypes were identified. Two particular serotypes, 4 and 19 were isolated from several species of animals and comprised 24% of the isolates studied. Since asymptomatic laboratory animals of several different species harbor serotypes of C. jejuni and C. coli that are potentially pathogenic to man, appropriate precautions should be instituted to minimize exposure of personnel to the organisms in laboratory animal feces. If suspected cases of zoonotic-related enteric campylobacteriosis involving laboratory animals do occur, serotyping of isolates would be a useful epidemiologic marker in studying the outbreak.

Cardiovascular changes in preterm infants nursed under radiant warmers

Radiant heat is known to increase insensible water loss and, to a certain extent, oxygen consumption. Little is known about its cardiovascular effects. We measured cardiac output, stroke volume, heart rate, and lower limb and skin blood flow in 20 preterm newborn infants nursed in an incubator and under a radiant warmer at an abdominal skin temperature of 36.5 degrees C. Mean (+/- SEM) birth weight was 1.57 (0.06) kg, gestational age 31.7 (0.4) weeks, and weight at examination 1.69 (0.02) kg; median postnatal age was 15 days. Skin and limb blood flow measurements increased by 44% to 55% with radiant heat (P less than .001 and P less than .01, respectively). Cardiac output increased by 5.4% (P less than .02) under the radiant warmer secondary to a small but significant (P less than .05) increase in heart rate. The changes in cardiac output during radiant heat administration are comparable to those reported for oxygen consumption.

Factors affecting nursery survival of very low birth weight infants

398 infants with birthweight (BW) 500-1500 g born from January 2 1982 to December 1983 were studied to determine incidence and survival rate by BW and gestational age (GA) categories and to determine causes of death and factors influencing mortality. 58% of the group survived. Factors other than those in the perinatal and postnatal period did not significantly influence survival. Infants with BW below 1000 g delivered by elective C-section had better survival than those delivered vaginally. Survival increased progressively with increasing BW and GA categories with GA more than BW being the limiting factor. Eleven (6.6%) of the deaths in the very low birth weight infants occurred during the nursery period after 28 days of age. These deaths would not have been addressed in the neonatal mortality.

Peripartum colloid osmotic pressures: correlation with serum proteins

Colloid osmotic pressure is a principal regulator of capillary fluid exchange. Alterations in colloid osmotic pressure in preeclamptic patients, as well as significant peripartum changes in colloid osmotic pressure in normotensive patients, are reported. In a study of 72 normotensive and preeclamptic patients, peripartum colloid osmotic pressure, serum albumin, and total serum protein were compared. Both groups exhibited significantly lower colloid osmotic pressure in the postpartum period than that measured antepartum. The mean antepartum colloid osmotic pressure in preeclamptic patients was significantly lower than in normotensive subjects. Regression equations were calculated [colloid osmotic pressure = 5.21 (total serum protein) -11.4 (r2 = 0.851)] and [colloid osmotic pressure = 8.1 (serum albumin) -8.2 (r2 = 0.891)]. Within the physiologic ranges most commonly reported for normotensive and preeclamptic patients, the use of these equations allowed calculation of colloid osmotic pressure to within 10% of measured values in 75 and 80% of the cases, respectively. Where direct measurement of colloid osmotic pressure is not readily available, calculated values may be helpful in patient management.

Cardiac output changes secondary to theophylline therapy in preterm infants

The cardiovascular effects of theophylline were studied in 11 clinically stable preterm infants. Theophylline was given as aminophylline using a loading dose of 6.8 mg/kg and a maintenance dose of 2 mg/kg every 8 hours intravenously. Cardiac output, stroke volume, and heart rate were measured using a combination of pulsed Doppler ultrasound and M-mode echocardiography. Compared with day 0, an increase was found in both cardiac output (P less than 0.01) and stroke volume (P less than 0.02) on days 1, 2, and 3. By day 7, stroke volume was comparable to pretreatment values, whereas cardiac output was still increased. Heart rate was augmented significantly (P less than 0.01) throughout the treatment period. Mean arterial blood pressure did not change. All but one of the neonates had serum theophylline concentrations between 6 and 13 mg/L. We conclude that both inotropic and chronotropic effects are evident during the first days of theophylline therapy. The metabolic cost of the increased cardiac output in the preterm infant with theophylline therapy deserves further attention.

Echocardiographic measurements in normal preterm and term neonates

To the purpose of better defining normative data on intracardiac dimensions and systolic time intervals in very low birth weight infants, we collected M-mode echocardiograms from 210 healthy preterm and term neonates with birth weights between 780 and 5,350 g and gestational ages ranging from 26 to 43 weeks. Fifty-nine neonates were less than 24 h, 62 were 25-48 h, and 89 were 48-144 h of age. Diastolic and systolic left ventricular dimensions increased gradually with advancing birth weight (r = +0.84 and 0.78). Left atrial and aortic root dimensions tended to show a parabolic relationship with birth weight, increments were reduced at higher birth weights (r = +0.92 and 0.85). The shortening fraction of the left ventricle (mean +/- SD 33.8 +/- 4.9%) and the left atrial/aortic ratio (1.16 +/- 0.10) were constant throughout all weight subgroups. Pre-ejection periods and ejection times of both ventricles were reduced in preterm infants due to their higher heart rates, but left and right ventricular PEP/ET ratios in preterm and term infants were comparable. Septal thickness in diastole and in systole tended to increase slowly with advancing birth weight, but correlation coefficients were low. This information is currently used as data base for a computer program to interpret M-mode echocardiograms performed in our nursery.

Deformability and intrinsic material properties of neonatal red blood cells

Whole cell and membrane deformability are essential for red blood cell (RBC) survival and for effective blood flow. Neonatal RBCs display several specific properties (eg, large size, high hemoglobin F) that could influence their deformation characteristics and contribute to their shortened life span. The present study was designed to compare selected rheologic properties (cellular deformability, pressure required to aspirate RBC into micropipettes, static and dynamic viscoelastic material properties) of neonatal and adult RBCs. RBC deformability, as studied by a rheoscope, was similar for neonates and adults over a shear stress range of 2.5 to 500 dyn/cm2. The pressure required to aspirate RBCs completely into 3.3-micron diameter pipettes was 129 +/- 87 dyn/cm2 for neonatal RBCs and 71 +/- 37 dyn/cm2 for adult RBCs. The aspiration pressure for neonatal and adult RBCs increased with increasing RBC volume, suggesting that the increased mean aspiration pressure for neonatal RBCs resulted from their larger volume. When RBCs with same volume and diameter were compared, the aspiration pressure tended to be smaller for neonatal RBCs than for adult cells. To characterize material properties determining RBC deformability, we measured membrane extensional (shear) and bending elastic moduli, the time constant for elastic recovery from extensional deformation and hemoglobin viscosity (ie, cytoplasmic viscosity) of neonatal and adult RBCs. Membrane surface viscosity and time constant for recovery from bending deformation were calculated. The extensional and bending moduli of neonatal RBCs were slightly smaller (10% and 16%, respectively) compared with adult cells. This suggests that the static resistance of neonatal RBC membrane to deformation and failure in response to a given force is slightly smaller. The time constant for recovery from extensional deformation of neonatal RBCs was larger by 14%, compared with adult cells. The time constant for bending deformation related to the RBC diameter and surface area was increased by 18% in the neonates. Membrane surface viscosity and hemoglobin viscosity were similar for both cell types. These results indicate that the deformability and viscoelastic properties of neonatal RBCs deviate only slightly from those of adult RBCs and that the increased aspiration pressure of neonatal RBCs is solely due to their large size. Some of the specific deformation characteristics observed in this study (increased aspiration pressure, decreased resistance to elastic deformation) may contribute to the shortened life span of neonatal RBCs.

Medium-chain triglycerides in infant formulas and their relation to plasma ketone body concentrations

A mild ketosis is known to prevail in the mother, fetus, and newborn infant during the 3rd trimester and in the early neonatal period. It has been shown that during an equivalent period in the rat ketone bodies are readily oxidized and serve as key substrates for lipogenesis in brain. Since medium-chain triglycerides are known to be ketogenic, preterm infants may benefit from dietary medium-chain triglycerides beyond the point of enhanced fat absorption. Our objective was to determine the ketogenic response in preterm infants (gestational age: 33 +/- 0.8 wk) fed three different isocaloric formulas by measuring the concentrations of 3-hydroxybutyrate and acetoacetate in the plasma of these infants. At the time of entrance to the study the infants were receiving 110 kcal/kg/24 h. Study I (11 infants): the infants were fed sequentially in the order; PM 60/40 (PM), Special Care Formula (SCF), and Similac 20 (SIM). In SCF greater than 50% of the fat consists of medium-chain length fatty acids while PM and SIM contain about 25%. The concentration of 3-hydroxybutyrate in plasma was significantly higher when infants were fed SCF than PM and SIM [0.14 +/- 0.03, 0.06 +/- 0.01, and 0.05 +/- 0.01 mM, respectively (p less than 0.01)]. Study II (12 infants); the infants were fed SCF, then SIM, or the reverse. The concentration of acetoacetate in plasma was 0.05 +/- 0.01 and 0.03 +/- 0.01 mM when infants were fed SCF and SIM, respectively (0.1 greater than p greater than 0.05). The concentrations of 3-hydroxybutyrate in plasma were similar to those measured in study I for the respective formulas.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood flow in the ascending and descending aorta in term newborn infants

The combination of 2-dimensional real-time and pulsed Doppler echocardiography provides a noninvasive method of measuring blood flow and has been used to study blood flow at the lower thoracic level in the descending aorta of the human fetus. Using these techniques, we evaluated the proportion of cardiac output distributed through the descending aorta in 20 healthy term newborn infants at 1-6 days of age. Blood flow in the ascending aorta was 759 +/- 135 ml/min (mean +/- S.D.) and in the descending aorta 482 +/- 92 ml/min indicating that 63.8% of the left ventricular output is distributed through the descending aorta. Peak systolic and mean blood flow velocities were comparable at the two sites, whereas the diameter of the descending aorta was 19% smaller than that of the ascending aorta. The changes in aortic blood flow were correlated with the changes in aortic diameter.

Neonatal jitteriness of unknown origin and circulating catecholamines

Jitteriness is a common problem affecting neonates. Although the cause can sometimes be determined by history or conventional laboratory evaluations, nevertheless, in many instances the cause of the jitteriness is unknown. To determine if either intracranial hemorrhage (ICH) or elevated catecholamines are responsible for jitteriness in neonates, we studied 34 healthy term neonates with normal hematocrits, serum glucose, Ca, Mg, Na, K and P. Thirteen of the infants had jitteriness as their only clinical problem. There were no differences in Apgar scores, birthweight, or gestational age in the two groups. Norepinephrine levels were significantly elevated in the jittery group as compared to the control group: 1276 +/- 574 vs. 914 +/- 338, p less than 0.05. Epinephrine levels were not different in the two groups. Intracranial hemorrhage was not found in any of the patients. Jittery neonates have increased sympathetic activity. What influence the increased levels have on other metabolic and hormonal systems is yet to be determined.

Cardiac output changes in newborns with hyperbilirubinemia treated with phototherapy

Phototherapy is known to increase peripheral blood flow in neonates, but information on the associated cardiovascular effects is not available. Using pulsed Doppler echocardiography we evaluated cardiac output and stroke volume in 12 preterm and 13 term neonates during and after phototherapy. We concomitantly measured arterial limb blood flow by strain gauge plethysmography and skin blood flow by photoplethysmography. Cardiac output decreased by 6% due to reduced stroke volume during phototherapy, whereas total limb blood flow and skin blood flow increased by 38% and 41%, respectively. Peripheral blood flow increments tended to be higher in the preterm than in the term infants. The reduced stroke volume during phototherapy may be an expression of reduced activity of the newborn during phototherapy. For healthy neonates the reduction in cardiac output is minimal, but for sick infants with reduced cardiac output, this reduction may further aggravate the decrease in tissue perfusion.

Pulsed Doppler determinations of cardiac output in neonates: normal standards for clinical use

Noninvasive monitoring of cardiac output can greatly facilitate the clinical assessment and management of neonates with cardiovascular compromise. To assess normal values of cardiac output in neonates, mean blood flow velocity was measured in the ascending aorta from a suprasternal approach using a range-gated, pulsed Doppler velocity meter, and aortic root diameter was determined from an M-mode echocardiogram. These techniques were combined, and cardiac output was evaluated in 59 healthy premature and 62 term newborn infants during the first week of life. Birth weights ranged from 780 g to 4,740 g and gestational age from 27 to 42 weeks. Cardiac output values increased linearly with advancing birth weight (r = +.94, P less than 0.001) and gestational age (r = +.95, P less than .001). Mean cardiac output values (+/- SD) per kilogram of body weight were 249 +/- 34 mL/min/kg and decreased with advancing birth weight: less than 1,500 g = 265 +/- 32 mL/min/kg; 1,500 to 2,500 g = 253 +/- 34 mL/min/kg; and greater than 2,500 g = 241 +/- 33 mL/min/kg. For clinical use, 325 mL/min/kg and 200 mL/min/kg can be used as upper and lower limits of normal, respectively. Doppler cardiac output estimates compared favorably with studies using invasive techniques.

Cardiac output in newborn infants with transient myocardial dysfunction

Decreased cardiac output is a common presumption in left ventricular myocardial dysfunction in neonates, but because of a lack of reliable noninvasive techniques, data on cardiac output are missing. We measured cardiac output by pulsed Doppler echocardiography in 22 newborn infants with left ventricular myocardial dysfunction diagnosed by M-mode echocardiography. Eleven neonates had severe perinatal asphyxia, seven had tachypnea, two hypoglycemia, and one septic shock; one had no symptoms. Right ventricular function was abnormal in 13 of the 22 infants. Hypotension was found in eight; cardiac output and stroke volume were low in 20. The abnormalities were more pronounced in infants with asphyxia. Six such infants were given dopamine (4 to 10 micrograms/kg/min). Within 1 hour, arterial blood pressure, cardiac output, stroke volume, and heart rate increased sharply, with normalization of the myocardial contractility; the other echocardiographic abnormalities normalized over 24 to 48 hours. Pulsed Doppler echocardiography is an advance in the detection and evaluation of therapy for left ventricular myocardial dysfunction in the neonate.

Cardiac output in infants of insulin-dependent diabetic mothers

The purpose of our study was to quantitate left ventricular outflow obstruction in the infant of the diabetic mother (IDM) through estimation of cardiac output by pulsed Doppler ultrasound. We evaluated 42 IDMs (White class B, C, or D) and compared them with two control groups, one similar in birth weight and the other similar in gestational age. Ventricular septal hypertrophy was found in 18 (43%) of 42 of the IDMs, but in none of the control infants. Morbidity increased with advancing septal thickness. None had hyaline membrane disease. Twenty-nine IDMs were asymptomatic, 11 of whom had septal hypertrophy. Thirteen IDMs developed congestive heart failure, seven of whom had septal hypertrophy. Cardiac output per kilogram diminished linearly with increasing septal thickness (r = -0.78, P less than 0.001) secondary to reduced stroke volumes at comparable heart rates. The IDMs had higher left atrial/aortic ratios and greater right ventricular systolic time intervals than the control infants. We conclude that cardiac output is significantly reduced in IDMs with septal hypertrophy. This reduction is secondary to reduced stroke volume and is directly related to the degree of septal hypertrophy.

Limitations of theophylline in the treatment of apnea of prematurity

Theophylline is commonly used to treat apnea of prematurity. To determine the effectiveness of theophylline with respect to gestational and postnatal age, we conducted a controlled study in 43 premature infants with idiopathic apnea. Three of the 21 treated and eight of the 22 control infants developed respiratory failure. Eight of the 11 infants with respiratory failure had gestational ages of less than 31 weeks and had more than four apneic episodes during the first day of life. In the treated infants without respiratory failure, the number of apneic episodes by 24-hour intervals declined six days earlier than in the control infants. Apnea disappeared, however, at a similar time in both groups. Three treated infants and three control infants had apneic episodes persisting beyond the neonatal period. Patients treated with theophylline did not develop respiratory failure as often as control infants did. However, despite a reduction of apneic episodes, theophylline did not shorten the course of apnea of prematurity.

Normal values of aortic root measurements in neonates

Aortic root diameter measurements were obtained during the first week of life by M-mode echocardiography using leading edge methodology during early diastole in 172 preterm and 228 term neonates. At least 40 newborns were included in each 500-g birth-weight subgroup from 750 to 4750 g. The aortic root diameter increased linearly from 0.63 +/- 0.04 cm in newborns with birth weights of 750-1249 g to 1.06 +/- 0.06 cm in newborns of 4250-4750 g.

Red blood cell aggregation in preterm and term neonates and adults

Aggregation of red blood cells (RBC) is a major determinant of blood viscosity and of blood circulation through vessels with slow flow (i.e. veins). RBC aggregation and plasma fibrinogen were studied in placental blood samples from 25 neonates with 24 to 41 wk of gestation and in blood from 13 normal adults. The rate and final extent of RBC aggregation were measured by means of a rheoscope (increase in light transmission during blood stasis). Both the rate and extent of RBC aggregation were low in the premature infants, increased with gestational age, and reached the highest values in the adults. Blood from seven infants with 24 to 28 wk of gestation did not show any significant RBC aggregation during the first minute of stasis. RBC aggregation was closely related to the fibrinogen level. Cross-suspension studies (neonatal RBC in adult plasma and adult RBC in neonatal plasma) showed that neonatal and adult RBC had the same aggregation pattern when they were suspended in the same plasma. Moreover, neonatal and adult RBC demonstrated the same strong aggregation when they were resuspended in 1% dextran. These results indicate that specific plasma properties are responsible for the decreased RBC aggregation observed in the neonates while their specific RBC properties do not affect RBC aggregation.

The effect of plasma glucose variability on neonatal outcome in the pregnant diabetic patient

Maternal glucose variability was studied in 154 pregnant diabetic patients hospitalized during the last month of their pregnancies. By means of several statistical analyses of the coefficient of variation for within-day plasma glucose variability, we found as follows. (1) There was a significant association between maternal glucose variability and neonatal outcome. (2) Patients with greater glucose variability had more episodes of hyperglycemia, but not hypoglycemia. (3) There was no correlation between maternal glucose variability and the birth weight of the infant. We are proposing the use of an index for glucose variability to monitor glucose control in pregnancy and predict neonatal outcome. Although absence of glucose variability will not ensure prevention of neonatal complications, there is a clear association between greater glucose variability and neonatal complications.

Geometry of neonatal and adult red blood cells

Red blood cell (RBC) geometry is a determinant of RBC deformability, survival time, osmotic resistance, and oxygen uptake. Because accurate information on the geometry of neonatal RBC appears lacking, a micropipette technique was employed to measure surface area and volume of individual neonatal and adult RBC. In addition, RBC diameter was determined microscopically. From these measurements, surface area index (actual surface area divided by area of sphere of same volume), swelling index (maximal volume divided by actual volume), minimum cylindrical diameter and mean thickness of RBC were calculated. Compared to adult cells, the volume of neonatal RBC was 21% larger, their surface area was 13% greater and their diameter 11% wider. The surface area-to-volume ratio of the neonatal RBC was 1.42 +/- 0.08 and that of the adult RBC was 1.49 +/- 0.06 (P less than 0.05). The minimum cylindrical diameter of the neonatal RBC was 3.04 +/- 0.25 microns and that of the adult RBC was 2.81 +/- 0.23 microns (P less than 0.05). Mean RBC thickness, surface area index and swelling index were not significantly different.

Colloid osmotic pressure: variations in normal pregnancy

Pregnancy is associated with an increase in the extravascular fluid by about two litres. The regulation of fluid flux across capillary membrane is dependent on the STARLING's forces. Thus increased fluid shift into the extravascular space may occur during pregnancy when the intra-capillary hydrostatic pressure exceeds the opposing influence of plasma colloid oncotic pressure (COP). In order to evaluate these forces more fully, COP, hematocrit (HCT), serum total solids (STS), mean blood pressure (MBP) and MBP-COP gradient (M-C) were measured cross-sectionally in 184 women with normal uncomplicated pregnancy. COP fell gradually during the first and second trimesters, lowest at 30-34 weeks, thereafter it rose. The relationship of COP and gestational age was best described by the quadratic equation. The patterns of changes of HCT and STS with respect to gestational age were similar to COP. MBP and M-C were linearly correlated to gestational age. The increment in M-C with advancing gestational age would promote fluid flux from intra to extravascular space in normal pregnancy.

Deformability of density separated red blood cells in normal newborn infants and adults

The deformability of neonatal and adult red blood cells (RBC) was studied using both unseparated and density (i.e., age) fractionated RBC. Blood samples were obtained from 10 normal newborn infants (placental blood) and 10 adults. Deformability was measured by direct microscopic observation of RBC subjected to shear stresses of 2.5-500 dynes/cm2 using a counter-rotating Rheoscope. There was no significant difference in deformability between unseparated neonatal and adult RBC at any shear stress. The 3% least dense ("youngest") RBC showed significantly decreased hemoglobin concentrations (MCHC), increased volumes (MCV) and elevated deformability at any shear stress when compared to the 3% most dense ("oldest") cells, with the values for the unseparated RBC lying between these two extremes. The least dense neonatal RBC had a significantly lower MCHC and higher deformability than the least dense adult cells; however, the most dense neonatal RBC had lost more volume than the adult cells (33 versus 17%), had a higher MCHC, and were less deformable than the most dense adult cells. This indicates that the accelerated decrease in deformability of aging neonatal RBC is related to the more pronounced increase in MCHC, which is the principal determinant of the internal viscosity of the RBC.

Infants with birth weight under 1500 g: physical, neurological, and developmental outcome

One hundred and seventy-eight infants with birth weights less than or equal to 1500 g born in 1973-1975 were followed for a period of 1-3 years, and the physical, neurological, and developmental outcome evaluated. Although there was a high incidence of maternal problems, these did not correlate with outcome. Asphyxia at birth followed by neonatal complications leading to ventilatory assistance was significantly correlated with poor outcome. Over 50% of infants less than 100 g birth weight required assisted ventilation, but the outcome in small ventilated infants was comparable to that of ventilated infants of 1001-1500 g birth weight. Infants with neurological abnormality showed a high incidence of associated abnormalities in growth, vision, hearing, and development. Spastic quadriplegia emerged as the most common neurological diagnosis. Despite the many perinatal problems, 82% of the group were normal neurologically and 66% developmentally. The overall outcome was generally favorable in these infants even for those requiring ventilation.

Colloid osmotic pressure in newborn infants: variations with birth weight, gestational age, total serum solids, and mean arterial pressure

Colloid osmotic pressure (COP) of blood was measured directly at birth with the Wescor membrane colloid osmometer (model 4100) in 91 appropriately grown, 11 large, and nine small for gestational age "well" newborn infants. COP correlated directly with birth weight (r = .726, P less than .00001) and gestational age (r = .753, P less than .00001). COP values for small for gestational age (SGA) and large for gestational age (LGA) infants were found to fall within the 95% prediction interval with regard to birth weight and gestational age for appropriate for gestational age (AGA) infants. Simultaneous measurements of COP, total serum solids, and central arterial mean blood pressure were made. The results showed that COP correlated directly with total serum solids (r = .89, P less than .0001) and mean arterial blood pressure (r = .660, P less than .001). Among the factors evaluated, total serum solids was the best predictor of COP.

Impact of a regional infant dispatch center on neonatal mortality

In 1976, a regional Infant Medical Dispatch Center (IMDC) was implemented in Southern California to improve the lives and well-being of the critically ill newborn infants by expediting location of beds in neonatal intensive care units. Comparison of birth weight-specific neonatal mortality rates among 701-2000 grams neonates before and after the program showed a six-fold improvement in hospitals served by the Center over hospitals not served by the Center during the two-year period. From 1975 to 1977, a 43.7 per cent improvement in neonatal mortality among the 701-2000 grams neonates with hyaline membrane disease was observed in the transported infants served by the Infant Medical Dispatch Center as compared to a 22.9 per cent improvement in the group of transported infants not served by IMDC. Both indicators had consistently shown a marked improvement associated with the IMDC program beyond the improvement of medical sciences over the two years. The data suggest that the improved outcome of the neonates referred by IMDC might be related to the improved efficiency of locating available neonatal intensive care beds.

Peripheral blood flow in the neonate; 1. Changes in total, skin, and muscle blood flow with gestational and postnatal age

Total peripheral blood flow and blood flow through the skin and muscle were measured in the calf with an electrocapacitance plethysmograph with counter pressure in a group of 62 "well" newborn infants (birth weight, less than 3500 g). Blood pressure in the contralateral leg was measured with an Arteriosonde 1010, and peripheral vascular resistance was calculated as mean blood pressure (mm Hg) divided by blood flow (ml per 100 ml tissue per min). The results show that total peripheral blood flow and blood flow through he skin and muscle correlated inversely with increasing birth weight and gestational age. Postnatally, total blood flow and blood flow through the skin and muscle decreased gradually during the first 7 days of life and in the rest of the neonatal period. Peripheral vascular resistance and resistance in the skin and muscle correlated directly with increasing birth weight and gestational age. Postnatally, peripheral vascular resistance and resistance in the skin and muscle increased during the first 7 days of life and the neonatal period.

Central venous pressure in preterm infants

Right atrial A-wave, mean and inspiratory pressures were measured serially every 6 h in 36 preterm infants--24 healthy and 12 with respiratory distress syndrome (RDS)--from the 2nd until 24th h of age. In healthy preterm infants, the right atrial A-wave averaged + 4.91 mm Hg with a range of + 2 and + 8 mm Hg and the right atrial mean pressure averaged + 1.62 with a range of -3 to + 4 mm Hg. Preterm infants developed RDS had significantly lower right atrial pressure (RAP) during the first 6 h of life than healthy preterm infants. RAP in preterm infants with RDS subsequently increased to normal range. RAP did not have any correlation with either birth weight or gestational age.

Baroreceptor and chemoreceptor responses to umbilical cord occlusion in fetal lambs

11 fetal lambs with gestational age of 116-135 days were studied while connected to a membrane-oxygenator replacing the ventilatory function of the placenta. Progressive increase in arterial oxygen tension from 20 to 220 mm Hg resulted in progressive decrease in baseline heart rate and baseline arterial blood pressure indicating presence of chemoreceptor activity over this wide range of arterial oxygen tension. The effect of 60 sec complete umbilical cord occlusion was studied at progressively higher arterial oxygen tension and it was concluded that the chemoreceptor activity at fetal normoxic condition is very brisk and is markedly attenuated at hyperoxic levels. Although it was not possible to completely separate baroreceptor and chemoreceptor reflexes involved in cardiovascular response to umbilical cord occlusion, it is postulated that the chemoreceptor and baroreceptor reflexes are complimentary during cardiovascular responses to umbilical cord occlusion.

Current patterns of neonatal morbidity and mortality in infants of diabetic mothers

Recent advances in antepartum fetal evaluation have contributed to a marked reduction in fetal deaths in pregnancies complicated by overt diabetes mellitus. To determine the effect of these changes on neonatal morbidity and mortality, a retrospective analysis of complications in 322 infants of diabetic mothers (IDM) in White classes B--R was undertaken. The majority (89 per cent) of the IDM were delivered at term with a mean gestational age of 38 weeks. Neonatal morbidity correlated significantly with gestational age, occurring in 80 per cent of the preterm and 40 per cent of the term infants. The overall incidence of complications was: hyperbilirubinemia 37 per cent, hypoglycemia 31 per cent, hypocalcemia 13 per cent, polycythemia 8 per cent, and necrotizing enterocolitis 2 per cent. Respiratory distress syndrome (RDS) occurred in 9 per cent and congenital malformations in 6 per cent of the infants. Nine infants died, and four of these deaths were due to anomalies. These data indicate that (1) a reduction in fetal mortality has been accompanied by a reduction in neonatal mortality; (2) neonatal morbidity has been decreased but remains significant in the IDM; and (3) congenital anomalies have replaced RDS as a major cause of neonatal death for the IDM.

Effect of phototherapy on nitrogen and electrolyte levels and water balance in jaundiced preterm infants

Twenty-four-hour metabolic balance studies were performed in ten jaundiced preterm infants, five light-treated (phototherapy) and five controls. Each of the light-treated infants was studied twice, once during phototherapy (period I) and once 48 hours after phototherapy (period II). Control infants were similarly studied during the corresponding days. Compared to period II and control infants, during period I the light-treated infants had less weight gain. Intestinal transit time was decreased by 50%. Fecal excretion of nitrogen, sodium, and potassium was increased. Stool water loss was increased twofold to threefold with a decrease in water balance. Unmeasured water loss was increased. These studies underscore the need for careful attention to fluid and caloric supplementation during phototherapy.

Effect of phototherapy on growth of low-birth-weight infants--two-year follow-up

The effect of phototherapy on subsequent growth of low-birth-weight infants has been evaluated at two-year follow-up of infants from two separate controlled neonatal studies. Growth of weight, length, and head circumference in the treated infants of Group I was slower than that of control subjects. Growth was comparable in treated infants and control subjects in Group II, and the two control groups, although not concurrent were also similar. Infants whose heads were growing at a normal rate, even though below 2 SD from the norms, were developing normally. Only infants who had deceleration in rate of head growth were abnormal. It is unlikely that phototherapy was responsible for the slow growth patterns seen in Group I, since these patterns were not reproducible in Group II.

Recent improvement in outcome for the small premature infant. Follow-up of infants with a birth weight of less than 1,500 grams

1. Developmental and neurologic outcome was determined for 176 premature infants of birth weight less than 1,500 gm, born during 1965-1970. 2. No significant difference in outcome was found when infants of birth weight 1,000 to 1,500 gm were compared with those weighing less than 1,000 gm. 3. The overall outcome is generally favorable, with 67% of the entire group noew deemed developmentally and neurologically normal. 4. Improvement in outcome in the small premature infant seems related to aggressive perinatal care, particularly monitoring of biophysical, biochemical and metabolic factors in the fetus and neonate;

Blood flow and venous distensibility in the upper and lower extremities of newborn infants

The electrocapacitance plethysmograph was utilized to measure peripheral blood flow and venous distensibility in 17 newborn infants and 20 adults. Measurements were made in the upper and lower extremities in each subject under identical environmental conditions. Blood flow in the forearm and calf were found to be significantly higher in infants than adults. In infants there were no significant differences in the blood flow between the upper and lower extremities. In contrast, in the adults, the blood flow was significantly higher in the upper than in the lower extremities. Similarly, venous distensibility was observed to be higher in infants than in adults. While no significant differences were observed in the venous distensibility between the upper and lower extremities in infants, the venous distensibility was found to be higher in the forearm than in the leg in adults.

Perinatal factors and neonatal morbidity in twin pregnancy

There were 177 pairs of twins reviewed. The incidence of twin pregnancy was 1:112.2 deliveries in a population consisting of 76.8 per cent Mexican-Americans. The incidence of breech, cesarean section, and assisted deliveries was higher in twins than singleton deliveries, and the incidence was higher in twin 2 than twin 1. Mortality rates, fetal and neonatal, were lower than those previously reported. Neonatal findings and complications include low Apgar scores, small-for-dates infants, hyaline membrane disease, hypoglycemia, hypocalcemia, hyperbilirubinemia, and congenital malformation. The increased incidence of deaths and morbidity in twin pregnancy, as compared to singleton pregnancy, was attributed to prematurity, and to complications and diseases pertaining to prematurity, rather than to twinning per se.

Effect of glucagon on blood glucose homeostasis in infants of diabetic mothers

Thirty infants of diabetic mothers (IDM) were randomly selected and divided into 3 groups of 10 babies each. Group A were used as controls. Group B received glucagon 300 mug/kg i.m. and Group C received glucagon 300 mug/kg i.v. at birth. Hypoglycemia developed in 6 infants in Group A and 4 infants in Group B. None of the infants in Group C had hypoglycemia. Mean blood glucose was higher in Group C in the first 3 hours than Group A, and higher in Group B in the first (/2-1 hour. I.v. glucshon, 300 mug/kg when given in the first 15 minutes after birth prevented hypoglycemia in IDM in the first hours of life.

Changes in cellular growth in newborn rats and rabbits exposed to photoirradiation

Effects of photoirradiation from lamps currently used in phototherapy on growth in newborn rats and rabbits were studied. The newborn animals subjected to 96 h of phototherapy were found to be smaller than comparable nonirradiated animals. Mean organ weight of the brain, liver, heart and kidney was lower in the photoirradiated groups than in the nonirradiated group. DNA, protein content, protein/DNA ratio, cell number and cell size were also significantly reduced (p= less than 0.01) in the photoirradiated groups when compared to the nonirradiated group. The degree of growth retardation was more pronounced in rats subjected to continuous photoirradiation than intermittent photoirradiation (12 h on and 12 h off).

Effect of phototherapy in preterm infants on growth in the neonatal period

A total of 120 preterm infants were randomly divided at 24 hr of age into three groups: Group I, controls; Group II, continuous phototherapy for 5 days; and Group III, intermittent phototherapy (12 hr on and 12 hr off) for 5 days. At the end of week 1 80% of the control group regained and surpassed their birth weight as opposed to 44 and 57.6% in the continuous and intermittent phototherapy groups, respectively. In weeks 2 and 3 both phototherapy groups had greater weight gain than the control group. Similar but less marked differences were observed in body lenth and head circumference in the three groups. Data suggest decreased growth during phototherapy with subsequent catch-up in growth during weeks 2 and 3. Differences were less marked between infants on intermittent (rather than continuous) phototherapy and controls. Increased metabolic demands and decreased intestinal absorption during phototherapy may be two of the factors responsible for the observed differences in growth in the three groups.