Effect of mode of delivery, parity and umbilical blood gas on first meconium passage in full-term healthy neonates.

The various physiologic factors which might influence the time of first meconium passage were studied in 62 healthy full-term newborn infants. Thirty-two babies were born vaginally and 30 by elective cesarean section. Infants born vaginally were more acidotic and passed first stool earlier compared to those born by cesarean section. The same applies to vaginally delivered babies when comparing babies born to primipara and others. Acidosis is a presumed mechanism, and a role of gastrointestinal hormones is suggested to be the possible mediator of increased motility in these babies.

Transcutaneous bilirubinometry: variability of TcB measurements on the forehead with crying.

We studied the effect of crying and facial expression on TcB readings at the forehead in 38 high-risk full-term newborn infants. Our study showed that crying and facial expression were significant factors affecting the TcB readings at the forehead. We recommend that TcB readings at the forehead should be obtained in a quiet condition.

Factors affecting transcutaneous bilirubin measurement: effect of daylight.

The purpose of this study was to determine whether daylight might affect the accuracy and reliability of TcB measurement at the forehead and sternum. One hundred and seven full-term newborn infants were divided into two groups. Babies in group I (N = 59) were kept near the window which was sometimes directly exposed to daylight, and babies in group II (N = 48) were kept on the door side of the room which had no direct daylight, during the first week of life. The result indicates that daylight is one of the significant factors affecting TcB measurement at the forehead, contributing to poor correlation between TcB reading at the forehead and serum bilirubin concentrations. We suggest the necessity of obtaining TcB readings at the forehead and sternum, at least, in order to improve the accuracy and reliability of such measurements in infants.

Transcutaneous bilirubinometry: effect of postnatal age.

The purpose of this study was to determine whether the postnatal age might affect the accuracy and reliability of transcutaneous bilirubin measurements. A total of 576 transcutaneous bilirubin measurements were performed on 336 Japanese full-term breast-fed newborn infants during the first 12 days of life. We divided them into three groups according to postnatal age and studied the effect of postnatal age on the accuracy and reliability of TcB measurements. Our study revealed that the most reliable site for transcutaneous bilirubin measurements changed from the forehead to the sternum with advancing postnatal age (i.e. forehead for 0-3 days, chest for 4-5 days, sternum for 6 days and later).

Initial response of serum bilirubin levels to phototherapy.

We demonstrated the phenomenon of transiently increasing total serum bilirubin within 4 h of phototherapy. We attempted to resolve the mechanism of this phenomenon in 29 hyperbilirubinemic full-term newborn infants who received continuous phototherapy for 24 h. Our present study suggests that this phenomenon may in part be bilirubin load (photobilirubin, photoisomers) from skin and subcutaneous bilirubin and/or peripheral capillary wall bilirubin into the blood stream pool, rather than delayed clearance of bilirubin and photoisomers from the blood stream to bile or urine. Further study is needed to determine these bilirubin compounds for safe and more effective phototherapy.

The transmission of ambient noise and self-generated sound in the human body.

It is commonly understood that ambient noise and sounds produced by a pregnant woman herself are propagated into the body and reach the unborn child in the uterus. However, it would be unethical to study the propagation of sound to the fetus directly, so the present study, which aimed to clarify this process from an acoustical point of view, used the stomach as a model of the womb. The following points were demonstrated: For sound waves in the stomach, no interference such as occurs outside the body was observed. However, in the range 2 to 3 kHz, a resonance peak was visible, which was probably due to the gastric air space. Observing an average spectrum of songs showed that the sound pressure level (SPL(dB)) in the medium to lower range (below 3 kHz) tended to be higher in the stomach than outside.

The relationship between rooming-in/not rooming-in and breast-feeding variables.

We studied the relationship between rooming-in/not rooming-in and breast-feeding variables such as breast feeding frequency, breast milk intake, supplements of other human milk or 5% glucose solution, cumulative weight loss, weight recovery and hyperbilirubinemia. We found that the breast feeding frequency was significantly higher in infants rooming-in than in those not rooming-in. Intake of breast milk on days 3 and 5 was significantly lower and maximum weight loss was significantly higher in infants rooming-in than in those not rooming-in. Infants rooming-in also had less supplement of other human milk compared with non-rooming-in infants (p less than 0.01). However, the weight increase per day from minimum to weight on day seven was higher in infants rooming-in than in non-rooming-in infants (39.3 +/- 21.4 g/day vs. 31.4 +/- 15.3 g/day, p less than 0.01). The frequent suckling by rooming-in infants may explain, in part, the better weight gain, since frequent suckling may decrease energy consumption by reducing movement and crying during the early days of life, thus contributing to better weight gain. Our study suggests that some of the neonatal feeding problems related to breast feeding could be eliminated by education of mothers and nurses and by changes in hospital policies and practices in breast feeding.

Breast-feeding frequency during the first 24 hours after birth in full-term neonates.

The relation between the frequency of breast-feeding and intake, weight loss, meconium passage, and bilirubin levels was studied in 140 healthy, full-term, breast-fed, Japanese neonates born vaginally without complications. Factors affecting the frequency of breast-feeding were also evaluated. Mothers nursed their neonates, on average, 4.3 +/- 2.5 (SD) times (range 0 to 11) during the first 24 hours after birth, and this frequency increased significantly to 7.4 +/- 3.9 times during the next 24 hours (P less than .001). There was a significant correlation between the frequency of breast-feeding during the first and second 24 hours after birth (r = .69, P less than .001). The frequency of breast-feeding during the first 24 hours correlated significantly with frequency of meconium passage (r = .37, P less than .01), maximum weight loss (r = -.22, P less than .05), breast milk intake on day 3 (r = .50, P less than .01) and day 5 (r = .34, P less than .05), transcutaneous bilirubin readings on day 6 (r = -.18, P less than .05), and weight loss from birth to time of discharge (day 7) (r = -.32, P less than .01). There was a strong dose-response relationship between feeding frequency and a decreased incidence of significant hyperbilirubinemia (transcutaneous bilirubin readings greater than or equal to 23.5) on day 6. The time of birth also affected the frequency of breast-feeding during the first 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical application of transcutaneous bilirubin measurement. Early prediction of hyperbilirubinemia.

The purpose of this study was to investigate whether hyperbilirubinemia (greater than or equal to 15 mg/dl) could be predicted by TcB readings at birth or change of TcB readings during the first 24 hours of life. Both the TcB at 24 hours and the ratio of increase of TcB during the first 24 hours per kg birthweight were useful in predicting the development of hyperbilirubinemia (greater than or equal to 15 mg/dl). The test could be used as a noninvasive screening procedure to detect infants at risk for significant hyperbilirubinemia on the first day of life.

Is it necessary to change the babies' position during phototherapy?

The purpose of this study was to determine whether position changes might affect the efficacy of phototherapy in decreasing total serum bilirubin concentrations. Forty-four full-term newborn infants with hyperbilirubinemia [greater than or equal to 256 mumol/l (15 mg/dl)] were divided into two groups. Position changes were made every 6 h during phototherapy on infants in the study group (N = 22), while no change in position was made in the control group (N = 22). No significant difference between groups was found in serum bilirubin concentration during or within 24 h after phototherapy. Poland's statement advocating position change every 6 h during phototherapy was not supported by a greater decrease of serum bilirubin in our study.

Difference in TcB readings between full term newborn infants born vaginally and by cesarean section.

We studied the influence of method of delivery on TcB readings at the forehead and sternum in full term neonates in the first week of life. Our present study demonstrated that TcB readings at the forehead and sternum of the infants delivered by cesarean section were significantly lower than readings from infants delivered vaginally without complications, from day 1 to day 7 of life (p less than 0.05). This is probably due to the decreased placental transfusion at cesarean section. The present study suggests that the degree of placental transfusion or time of cord clamping may be more influential than meconium passage or weight loss on serum bilirubin levels in the first week of life.

Transcutaneous bilirubinometry. Interinstrumental variability of TcB instruments.

We studied the interinstrumental variability of the transcutaneous bilirubin meter (TcB) in 35 high risk neonates, using eight commercially available TcB instruments. Our study showed that commercially available TcB instruments were stable and had little interinstrumental variability for repeated TcB measurements at the forehead, chest, and sternum.

Transcutaneous bilirubinometry in normal Japanese infants.

We performed TcB readings in healthy full-term breast-fed Japanese infants from birth to seven days, and attempted to establish the normal range. TcB readings from Japanese infants were significantly higher over a longer period compared with Caucasian infants. The age of peak TcB readings in Japanese newborn infants was day 6, significantly later than that of Caucasian infants, day 3-4. We also attempted to estimate the total serum bilirubin concentrations using regression line relating TcB readings to serum bilirubin concentrations. Our study demonstrated that estimated total serum bilirubin concentration from forehead TcB readings was 0.56 +/- 0.35 mg/dl at birth, thereafter increasing to 6.8 +/- 0.5 mg/dl on day 1 and reaching a maximum of 12.6 +/- 2.5 mg/dl on day 6. These values and pattern in Japanese neonatal jaundice were significantly different from those of Caucasian children, but were similar to values and patterns from American Indians, Alaskan Eskimo, and other Asian full-term newborn infants. Thus TcB measurement may be useful for observation of the course of neonatal jaundice.

Transcutaneous bilirubinometry: bilirubin kinetics of the skin and serum during and after phototherapy.

Skin bilirubin (transcutaneous bilirubinometry, TcB, reading) and serum bilirubin kinetics were studied in 20 full-term hyperbilirubinemic infants during and after phototherapy. TcB readings at the chest site decreased after 2 h of phototherapy from 28.0 to 21.3 (25% of initial TcB reading, p less than 0.001) and thereafter continued to decrease in a nonlinear fashion through the first 24 h of phototherapy. However, TcB readings after 12 h of phototherapy were about 50% of the initial readings (p less than 0.001), declining minimally during the second 12 h of phototherapy, suggesting saturation kinetics. While serum bilirubin levels remained unchanged during the first 4 h of phototherapy, thereafter they showed a rapid decline to 12 h of phototherapy. The rate of decline decreased during the second 12 h of phototherapy, but serum bilirubin levels still decreased significantly from 16.9 to 14.9 mg/dl. Although TcB readings showed saturation kinetics during the second 12 h of phototherapy, the serum bilirubin levels were shown to decrease significantly. This suggests that the main site of action of phototherapy may be intravascular at this stage, rather than the skin and subcutaneous capillary bed as in the early stage of phototherapy.

Transcutaneous bilirubinometry: serum bilirubin measurement using transcutaneous bilirubinometer (TcB). A preliminary study.

While the transcutaneous bilirubinometer (TcB) was originally developed for use as a jaundice meter, we have shown that it can also be used as a bedside instrument for direct measurement of serum bilirubin. An analysis of 130 samples indicates that total serum bilirubin measurement using the TcB is simple and accurate. A comparison with the AO bilirubinometer showed a highly significant coefficient or correlation (r = 0.99) for total serum bilirubin concentration. The addition of hemolysates caused no effect on TcB reading obtained by the TcB instrument, even at levels above those usually encountered in sera of newborn infants. The AO cuvette is very suitable for use in this measurement, since this method requires less than 15 microliters of serum. One of the disadvantages of this method may be that it yields somewhat lower (5%) than actual serum bilirubin concentrations in the range above 20 mg/dl, and somewhat higher (20%) than actual serum bilirubin concentrations in the range below 10 mg/dl. Our study demonstrated the TcB instrument to be a useful device for bedside determination of serum bilirubin in the screening of neonatal hyperbilirubinemia. However, though useful as a screening test, it does not provide such an accurate determination of serum bilirubin concentration as the AO bilirubinometer.

Transcutaneous bilirubinometry. Evaluation of accuracy and reliability in a large population.

A total of 576 transcutaneous bilirubin measurements were performed on 336 Japanese full-term breast-fed newborn infants during the first twelve days of life. Our present study revealed that transcutaneous bilirubin measurements obtained from the forehead, chest, and sternum correlated well with serum bilirubin concentrations measured by AO bilirubinometer (0.910-0.922, p less than 0.001, n = 576). The 95% confidence limits were +/- 3.04 mg/dl for the forehead, +/- 2.85 mg/dl for the chest, and +/- 2.84 mg/dl for the sternum readings. The overall mean of values from the forehead, chest and sternum, when compared with individual means, was found to correlate better with serum bilirubin concentrations (r = 0.930, p less than 0.001, n = 576) and improve the 95% confidence limits to +/- 2.68 mg/dl. These results demonstrated that the accuracy and reliability of TcB measurement could be increased further with multiple site measurement. The study clearly indicates that transcutaneous bilirubinometry is useful for clinical screening of serum bilirubin levels in Japanese full-term newborn infants.

Transcutaneous bilirubinometry. Effect of irradiation on the skin bilirubin index.

We studied the relation between irradiation and the percent decrease of skin and serum bilirubin during phototherapy. There was a significant positive correlation between the percent decrease of transcutaneous bilirubinometry readings at the sites exposed directly to light (chest) and irradiation (r = 0.593, p less than 0.001, n = 32). A significant positive correlation was also found between the percent decrease of serum bilirubin concentration and irradiation (r = 0.587, p less than 0.001, n = 32), and the percent decrease of skin bilirubin at exposed sites (chest) and the percent decrease of serum bilirubin concentration (r = 0.481, p less than 0.001, n = 32). Thus, light energy quantitatively affects skin and serum bilirubin. In order to determine the optimal effective wavelength and irradiation energy for phototherapy, it is necessary to examine skin bilirubin kinetics in detail during phototherapy.

Incidence and severity of retinopathy in low birth weight infants monitored by TCPO2.

The incidence and severity of retinopathy of prematurity (ROP) were studied in 561 survivors of low birth weight infants (LBWIs) weighing under 2,000g. They were the survivors out of 604 LBWIs admitted to Okayama National Hospital during the five years from January 1981 to December 1985. The tcPO2 of all the LBWIs on the respirator or under oxygen administration was monitored using an Oxymonitor SM 361. The upper limit of tcPO2 was maintained between 50 to 80 torr. The ophthalmologic funduscopy was continued until 12 months of age. The early active stages of ROP were recorded by "the International Classification 1984". The cicatricial change of retina was classified by the criteria of the Joint Committee for the Study of Retrolental Fibroplasia in Japan. In the survivors, 55 cases of active ROP were found. (Stage 1:29 cases, 2:17, 3:9, and 4:0) In the survivors, 27 cases of cicatricial ROP were found, (Grade I:27 cases, II:0, III:0, IV:0) None of them developed blinding retinopathy. Neither the artificial ventilation nor the duration of oxygen administration influenced the incidence of ROP with statistical significance. The incidence and severity of ROP in this study seems to be one of the lowest among those hitherto published. Though our study is not a controlled one, it can be concluded that tcPO2 monitoring eliminates the blinding ROP.