Arterial Blood pH Research Articles

Prenatal treatment of severe congenital erythropoetic porphyria (CEP) – a case report

Introduction: Less than 3% of porhpyhia cases affect children and CEP is the most severe.Case report: We report a case of a 21‐year‐old second digravida whose first pregnancy terminated with intrauterine death in the 27th week of gestation due to hydrops fetalis, cause unknown. The pathologist found organ infiltration with blastic blood elements. The patient was referred to our unit in the 25th week of the second pregnancy with oligohydramnion, ascites, hepatosplenomegaly, and generalized hydrops. The mother was AB Rh‐positive, with negative results for irregular antibodies, CMV, toxoplasmosis, and parvovirus B19. The initial cordocentesis showed severe anemia (Hct 7.7, Hgb 27, RBC 0.89, WBC 2.3, Plt 72), fetal karyotype: 46XY. Virologic examination, direct Coombs test, and amniotic fluid culture were negative. We treated the anemia with five intrauterine transfusions of O Rh‐negative erythrocyte concentrate. In the 25th week the Hgb was 59, during treatment it reached 91 (week 26), 120 (week 27), 134 (week 28), 114 (week 31), and 119 in the 33rd week, respectively. A male fetus was delivered in the 33rd week, with sanguineous amniotic fluid, birth weight 2370 g, APGAR 6‐7‐8, and arterial blood pH 7.25. The newborn had hepatosplenomegaly, anemia, and skin suffusions. Mild RDS was stabilized with nCPAP. From the fourth day, there was macroscopic hematuria. The treatment of renal failure was successful, the skin changes remained as the dominating sign. Eighteen days postpartum the diagnosis of congenital erythroid porphyria (autosomal recessive) was established based on the skin excoriation and urine examination for porphyrins.Discussion: This rare case of ascites, anemia and thrombocytopenia was diagnosed postnatally, but symptomatic treatment enabled the delivery of a fetus that could be successfully treated postnatally with umbilical blood transfusion.Conclusion: In all cases of unexplained ascites or hydrops the possibility of CEP should be considered.

Role of nitric oxide in acidosis-induced intestinal injury in anesthetized rats

We investigated the pathogenic mechanism(s) of small intestinal injury during acidosis in relation to circulating nitric oxide (NO) in an experimental rat model. Rats were anesthetized, paralyzed, and mechanically ventilated with room air. Hydrochloric acid (0.16 mmol bolus followed by 0.132 mmol/kg/h) was infused through the jugular vein for 5 hours. Control rats received a saline infusion. Arterial blood gases, blood pressure, and blood pH were measured every 30 minutes. The involvement of NO in this acidosis model was assessed by measuring plasma concentration of nitrite/nitrate (NOx) and by evaluating inducible NO synthase (iNOS) expression in small intestinal mucosa. Intestinal injury was assessed by measuring myeloperoxidase (MPO) activity, thiobarbituric acid reactants (TBARS), and histologic scores. HCl infusion was associated with hypotension, decreased blood pH, increased plasma concentration of NOx, augmented intestinal mucosal iNOS expression, MPO activity, TBARS, and histopathologic injury scores. Pretreatment with an iNOS inhibitor, aminoguanidine (AG, 50 mg/kg), reversed HCl-induced hypotension without a change in blood pH. HCl-induced lesions, MPO activity, TBARS, and plasma NOx production were decreased by AG. Our data show that the pathogenic mechanisms of acidosis-induced small intestinal lesions involve up-regulation of NO production by increased expression of iNOS and augmentation of superoxide radicals and MPO activity. (J Lab Clin Med 2001;138:270-6)

The use of umbilical artery Doppler velocimetry in the monitoring of pregestational diabetic pregnancy

Purpose: To assess whether umbilical artery Doppler velocity waveform analysis can predict adverse perinatal outcomes for pregnancies complicated with pre‐existing diabetes mellitus (types 1 and 2 diabetes mellitus).Methods: All diabetic pregnancies (types 1 and 2) delivered at Mater Mothers' Hospital, Australia, between 1st January 1995 and 31st December 1999, were included. All pregnant diabetic women were monitored with umbilical artery Doppler velocimetry at 28, 32, 36, and 38 weeks gestation. Umbilical artery Doppler study was repeated on weekly basis for pregnancies complicated by macrosomia, polyhydramnios, or fetal growth restriction. Adverse perinatal outcome was defined as pregnancies with one or more of the following: small‐for‐gestational age (birth weight <10th centile), cesarean section for non‐reassuring cardiotocography, fetal acidemia at delivery (cord blood arterial pH < 7.2), 1‐min Apgar of ≤3, 5‐min Apgar of <7, hypoxic ischaemic encephalopathy, stillbirth and perinatal deaths. Abnormal umbilical artery Doppler index was defined as systolic/diastolic ratio of 95th centile or higher for gestation (including absent or reversed end‐diastolic flow). The incidence of adverse perinatal outcomes was compared between those with normal umbilical artery Doppler and those with elevated systolic/diastolic (S/D) ratio.Results: One hundred and four pregnancies had umbilical arterial Doppler studies performed during the study period. Twenty‐three pregnancies (22.1%) had elevated S/D ratio of the umbilical artery Doppler velocimetry. If the scans were performed within 2 weeks of delivery, 71% of pregnancy with abnormal umbilical Doppler study have adverse outcome. For umbilical artery Doppler studies performed within 1 week of delivery, the sensitivity was 35%; specificity was 94%; positive predictive value was 80%; and negative predictive value was 68%. However, only 30% of women with adverse perinatal outcomes had abnormal umbilical Doppler flow.Conclusion: Elevated umbilical arterial Doppler S/D ratio is associated with adverse perinatal outcomes. However, the majority of diabetic pregnancies with adverse perinatal outcomes have normal umbilical artery Doppler velocimetry. Thus, this could be a useful test for monitoring, but is not a good predictor of adverse perinatal outcomes.

Adaptation of cardiovascular responses to repetitive umbilical cord occlusion in the late gestation ovine fetus.

1. The impact of repeated umbilical cord occlusion on the normal maturation of fetal heart rate (FHR) and mean arterial pressure (MAP) and the cardiovascular responses to successive umbilical cord occlusion was investigated over a 21 day period in the latter part of gestation. 2. Fifteen chronically instrumented sheep (control group n = 6; occlusion group n = 9) were studied for 21 days (113-133 days of gestation, term = 145 days) with umbilical cord occlusions (90 s duration) performed every 30 min for 1-4 h each day. On days 1, 9 and 18, FHR, FHR variation and MAP were monitored continuously and fetal arterial blood gases, pH and metabolites were measured at predetermined intervals. The baroreflex response to 75-100 microg phenylephrine (I.V.) was tested on days 1 and 18. 3. Basal FHR decreased (DeltaFHR: control, 34.6 +/- 3.6 beats x min(-1); occlusion, 36.9 +/- 2.7 beats x min(-1)) and MAP increased (DeltaMAP: control, 3.1 +/- 1.7 mmHg; occlusion, 5.2 +/- 2.1 mmHg) to a similar extent in control and occlusion groups between days 1 and 21 of the study. There was a small decline in FHR variation over the 21 day study in occlusion, but not control, group fetuses. 4. The magnitude of the fall in FHR decreased and the rise in MAP increased, despite similar changes in blood gases in response to umbilical cord occlusion, over the course of the 21 day study. Despite a significant decline in the ratio of DeltaFHR to DeltaMAP on days 9 and 18 compared to day 1, there was no difference between control and occlusion groups in baroreflex sensitivity. However DeltaFHR/DeltaPO2, an index of chemoreceptor sensitivity, had decreased by day 9 and 18 compared to day 1. 5. The cardiovascular responses to umbilical cord occlusion are altered with repetitive occlusions during the latter part of gestation, with a decrease in DeltaFHR/DeltaMAP, which does not involve changes in baroreflex sensitivity, but may involve changes in chemoreceptor sensitivity. However, repeated umbilical cord occlusion appears to have no impact on baseline cardiovascular control since there was no change in the normal maturational decrease in FHR and rise in MAP.

Effect of air breathing on acid-base and ion regulation after exhaustive exercise and during low pH exposure in the bowfin, Amia calva.

To explore a potential conflict between air breathing and acid-base regulation in the bowfin (Amia calva), we examined how individuals with access to air differed from fish without air access in their response to acidosis. After exhaustive exercise, bowfin with access to air recovered significantly more slowly from the acidosis than fish without air access. While arterial blood pH (pH(a)) of fish without air access recovered to resting levels by 8 h, pH(a) was still significantly depressed in fish having access to air. In addition, Pco(2) was slightly more elevated in fish having air access than those without it. Fish with access to air still had a significant metabolic acid load after 8-h recovery, while those without air access completely cleared the load within 4 h. These results suggest that bowfin with access to air were breathing air and, consequently, were less able to excrete CO(2) and H(+) and experienced a delayed recovery. In contrast, during exposure to low pH, air breathing seemed to have a protective effect on acid-base status in bowfin. During exposure to low pH water, bowfin with access to air developed a much milder acidosis than bowfin without air access. The more severe acidosis in fish without air access was caused by an increased rate of lactic acid production. It appears that enhanced O(2) delivery allowed air-breathing bowfin to avoid acidosis-induced anaerobic metabolism and lactic acid production. In addition, during low pH exposure, plasma Na(+) and Cl(-) concentrations of fish without air access fell slightly more rapidly than those in fish with air access, indicating that the branchial ventilatory changes associated with air breathing limited, to some degree, ion losses associated with low pH exposure.

Continuous Venovenous Renal Replacement Therapy Using a Conventional Infusion Pump

To evaluate continuous venovenous hemofiltration and hemodiafiltration with a conventional infusion pump in a pediatric sized animal model. Fourteen Maryland pigs weighing 8 to 13 kg were used. A conventional infusion pump (IVAC 571), with a flow of 900 ml/h and a pediatric hemofilter of 0.22 m2 were used. Ringer's solution was used for both the dialysate and the replacement fluid. Each experiment included 1 hour of hemofiltration and 1 hour of hemodiafiltration. Heart rate, arterial blood pressure, pH, Na, K, Cl, and hematocrit were measured every 30 minutes. Mean ultrafiltrate flow was 249.7 +/- 100.3 ml/hr, 240.5 +/- 109.5 ml/hr with hemofiltration and 271 +/- 101.1 ml/hr with hemodiafiltration, the differences not being significant. No significant changes were seen in heart rate, blood pressure, hematocrit, electrolytes, or pH. Pressure in the circuit rose from 107.7 +/- 70.3 mm Hg at the beginning of the experiment to 234.2 +/- 118.1 mm Hg after 2 hours (p < 0.05). The technique was well tolerated by all the pigs. Continuous venovenous hemofiltration and hemodiafiltration with a conventional infusion pump is a possible alternative to conventional methods of extrarenal replacement therapy in neonates and infants.

Intravenous anaesthesia using detomidine, ketamine and guaiphenesin for laparotomy in pregnant pony mares

Objective To characterize intravenous anaesthesia with detomidine, ketamine and guaiphenesin in pregnant ponies.Animals Twelve pony mares, at 260–320 days gestation undergoing abdominal surgery to implant fetal and maternal vascular catheters.Materials and methods Pre-anaesthetic medication with intravenous (IV) acepromazine (30 µg kg−1), butorphanol (20 µg kg−1) and detomidine (10 µg kg−1) preceded induction of anaesthesia with detomidine (10 µg kg−1) and ketamine (2 mg kg−1) IV Maternal arterial blood pressure was measured directly throughout anaesthesia and arterial blood samples were taken at 20-minute intervals for measurement of blood gases and plasma concentrations of cortisol, glucose and lactate. Anaesthesia was maintained with an IV infusion of detomidine (0.04 mg mL−1), ketamine (4 mg mL−1) and guaiphenesin (100 mg mL−1) (DKG) for 140 minutes. Oxygen was supplied by intermittent positive pressure ventilation (IPPV) adjusted to maintain PaCO2 between 5.0 and 6.0 kPa (38 and 45 mm Hg), while PaO2 was kept close to 20.0 kPa (150 mm Hg) by adding nitrous oxide. Simultaneous fetal and maternal blood samples were withdrawn at 90 minutes. Recovery quality was assessed.Results DKG was infused at 0.67 ± 0.17 mL kg−1 hour−1 for 1 hour then reduced, reaching 0.28 ± 0.14 mL kg−1 hour−1 at 140 minutes. Arterial blood gas values and pH remained within intended limits. During anaesthesia there was no change in heart rate, but arterial blood pressure decreased by 10%. Plasma glucose and lactate increased (10-fold and 2-fold, respectively) and cortisol decreased by 50% during anaesthesia. Fetal umbilical venous pH, PO2 and PCO2 were 7.34 ± 0.06, 5.8 ± 0.9 kPa (44 ± 7 mm Hg) and 6.7 ± 0.8 kPa (50 ± 6 mm Hg); and fetal arterial pH, PO2 and PCO2 were 7.29 ± 0.06, 4.0 ± 0.7 kPa (30 ± 5 mm Hg) and 7.8 ± 1.7 kPa (59 ± 13 mm Hg), respectively. Surgical conditions were good but four ponies required a single additional dose of ketamine. Ponies took 60 ± 28 minutes to stand and recovery was good.Conclusions and clinical relevance Anaesthesia produced with DKG was smooth while cardiovascular function in mare and fetus was well preserved. This indicates that DKG infusion is suitable for maintenance of anaesthesia in pregnant equidae.

Effects of one-to-one Labor Support on Labor Pain, Labor Stress Response, Childbirth Experience and Neonatal Status for Primipara

This study was designed to investigate the effect of one-to-one labor support on labor pain, labor stress response, childbirth experience and neonatal status for primipara by a quasi experiment (nonequivalent control group pretest-posttest design), from April 30, 1999 to February 20, 2000.The subjects of this experiment consisted of eighty two primipara with single gestation, full term, uncomplicated pregnancies. Forty one were in the experimental group and forty one in the control group. Their mean age was 25.95 years, their mean gestation period was 39.9 weeks.A caring package of one-to-one labor support had three components. Physical support consisted of massage, back pressure, touch. Emotional support was provided by a continuous nurse's presence, acceptance and encouragement. Informational support involved teaching breathing skills, relaxation skills and knowledge about the labor process.Data assessed labor pain, pulse rate and blood pressure to measure labor stress response. Also, in measuring the value of labor stress response, plasma epinephrine, plasma norepinephrine and serum cortisol were measured. In the 24 hours after birth, the data for the postpartum mother's childbirth experiences was collected. Umbilical cord arterial blood pH, one minute and five minute Apgar score were measured after birth.Data was analyzed by t-test, Chi-square-test, repeated measures ANOVA, ANCOVA with SAS Program.The results were as follows; 1. Labor pain was significantly low in the experimental group(P=.016).2. No significant group effects were found, but significant time effects were found for plasma epinephrine, norepinephrine, serum cortisol, pulse rate and blood pressure.3. The childbirth experience of the experimental group was significantly more positive than the control group (P =.005).4. The umbilical cord arterial blood pH of the experimental group was significantly higher than the control group(P=.014). There was no significant difference between the two groups in neonatal one minute and five minute Apgar scores.In conclusion, these findings indicate that one-to-one labor support could be effective in decreasing labor pain, and increasing positive childbirth experiences, also increasing the neonatal umbilical cord arterial blood pH for primipara. So, one-to-one labor support could be applied as an effective nursing treatment for primipara.

Modelo de anestesia em coelhos para procedimentos no tórax

A intubação endotraqueal em coelhos é dificil. O risco anestésico não é desprezível pela estreita margem de segurança entre o plano anestésico e o óbito. Tais fatos despertaram nosso interesse por uma solução simples e segura. Dez animais machos receberam por via intramuscular acepromazina, cetamina e xilazina. Após dez minutos procedeu-se exposição do ligamentum cricothyroideum , o qual foi incisado para colocação de tubo endotraqueal iniciando-se a administração de oxigênio e halotano. A punção arterial foi realizada para controle da pressão arterial média. Procedeu-se toracotomia no quinto espaço intercostal esquerdo com biópsia do pulmão e colabamento pulmonar, iniciando-se a ventilação seletiva do pulmão contra-lateral. Amostras sangüíneas, para medida do pH, foram colhidas no início do procedimento, após o colabamento pulmonar e no final, antes da expansão do pulmão, 30 minutos após o colabamento. Fechado o tórax, foi retirado o tubo endotraqueal tão logo o animal apresentasse recuperação dos reflexos e a seguir suturado ligamentum cricothyroideum. Os animais foram submetidos a eutanásia 14 dias após, quando procedeu-se a nova biópsia pulmonar, a retirada da traquéia e da laringe, para exame. Concluiu-se que este é um procedimento simples e seguro de anestesia para cirurgia torácica em coelhos.

Effects of respiratory acidosis and alkalosis on the distribution of cyanide into the rat brain.

The aim of this study was to determine whether respiratory acidosis favors the cerebral distribution of cyanide, and conversely, if respiratory alkalosis limits its distribution. The pharmacokinetics of a nontoxic dose of cyanide were first studied in a group of 7 rats in order to determine the distribution phase. The pharmacokinetics were found to best fit a 3-compartment model with very rapid distribution (whole blood T(1/2)alpha = 21.6 +/- 3.3 s). Then the effects of the modulation of arterial pH on the distribution of a nontoxic dose of intravenously administered cyanide into the brains of rats were studied by means of the determination of the permeability-area product (PA). The modulation of arterial blood pH was performed by variation of arterial carbon dioxide tension (PaCO2) in 3 groups of 8 anesthetized mechanically ventilated rats. The mean arterial pH measured 20 min after the start of mechanical ventilation in the acidotic, physiologic, and alkalotic groups were 7.07 +/- 0.03, 7.41 +/- 0.01, and 7.58 +/- 0.01, respectively. The mean PAs in the acidotic, physiologic, and alkalotic groups, determined 30 s after the intravenous administration of cyanide, were 0.015 +/- 0.002, 0.011 +/- 0.001, and 0.008 +/- 0.001 s(-1), respectively (one-way ANOVA; p < 0.0087). At alkalotic pH the mean permeability-area product was 43% of that measured at acidotic pH. This effect of pH on the rapidity of cyanide distribution does not appear to be limited to specific areas of the brain. We conclude that modulation of arterial pH by altering PaCO2 may induce significant effects on the brain uptake of cyanide.

Rat muscle microvascular PO2 kinetics during the exercise off-transient.

Dependent upon the relative speed of pulmonary oxygen consumption (VO2) and blood flow (Q) kinetics, the exercise off-transient may represent a condition of sub- or supra-optimal perfusion. To date, there are no direct measurements of the dynamics of the VO2/Q relationship within the muscle at the onset of the work/recovery transition. To address this issue, microvascular PO2 (PO2,m) dynamics were studied in the spinotrapezius muscles of 11 female Sprague-Dawley rats (weight approximately 220 g) during and following electrical stimulation (1 Hz) to assess the adequacy of Q. relative to VO2 post exercise. The exercise blood flow response (radioactive microspheres: muscle Q increased approximately 240 %), and post-exercise arterial blood pH (7.40 +/- 0.02) and blood lactate (1.3 +/- 0.4 mM x l(-1)) values were consistent with moderate-intensity exercise. Recovery PO2,m (i.e. off-transient) rose progressively until baseline values were achieved ((Delta)end-recovery exercise PO2,m, 14.0 +/- 1.9 Torr) and at no time fell below exercising PO2,m. The off-transient PO2,m was well fitted by a dual exponential model with both fast (tau = 25.4 +/- 5.1 s) and slow (tau = 71.2 +/- 34.2 s) components. Furthermore, there was a pronounced delay (54.9 +/- 10.7 s) before the onset of the slow component. These data, obtained at the muscle microvascular level, support the notion that muscle VO2 falls with faster kinetics than muscle Q during the off-transient, such that PO2,m increases systematically, though biphasically, during recovery.

Fumonisin B(1) increases serum sphinganine concentration but does not alter serum sphingosine concentration or induce cardiovascular changes in milk-fed calves.

Fumonisin B(1) is the most toxic and commonly occurring form of a group of mycotoxins that alter sphingolipid biosynthesis and induce leukoencephalomalacia in horses and pulmonary edema in pigs. Purified fumonisin B(1) (1 mg/kg, iv, daily) increased serum sphinganine and sphingosine concentrations and decreased cardiovascular function in pigs within 5 days. We therefore examined whether the same dosage schedule of fumonisin B(1) produced a similar effect in calves. Ten milk-fed male Holstein calves were instrumented to obtain blood and cardiovascular measurements. Treated calves (n = 5) were administered purified fumonisin B(1) at 1 mg/kg, iv, daily for 7 days and controls (n = 5) were administered 10 ml 0.9% NaCl, iv, daily. Each calf was euthanized on day 7. In treated calves, serum sphinganine concentration increased from day 3 onward (day 7, 0.237 +/- 0.388 micromol/l; baseline, 0.010 +/- 0.007 micromol/l; mean +/- SD), whereas, serum sphingosine concentration was unchanged (day 7, 0.044 +/- 0.065 micromol/l; baseline, 0.021 +/- 0.025 micromol/l). Heart rate, cardiac output, stroke volume, mean arterial pressure, mean pulmonary artery pressure, pulmonary artery wedge pressure, central venous pressure, plasma volume, base-apex electrocardiogram, arterial Po(2), and systemic oxygen delivery were unchanged in treated and control calves. Fumonisin-treated calves developed metabolic acidosis (arterial blood pH, 7.27 +/- 0.11; base excess, -9.1 +/- 7.6 mEq/l), but all survived for 7 days. We conclude that calves are more resistant to fumonisin B(1) cardiovascular toxicity than pigs.

Outcomes among term infants when two-hour postnatal pH is compared with pH at delivery

Objective: This study was undertaken to measure infant outcomes when pH at birth was compared with neonatal pH determined within 2 hours of age. Study Design: We retrospectively studied term infants born between January 1, 1988, and August 31, 1998, who had umbilical artery blood pH measured at birth and again from the radial artery or umbilical artery within 2 hours after birth. Statistical significance was determined with the χ2 test. Odds ratios and 95% confidence intervals were calculated by means of the Mantel-Haenszel method. Results: Data from a total of 1691 infants were analyzed: 178 (11%) had acidemia at birth (pH of <7.20) that persisted through the first 2 hours after birth; 110 (6%) had development of acidemia after birth; and 594 (35%) were born with a cord pH of <7.20 that improved after delivery. The remaining 809 infants (48%) did not have acidemia either at birth or during the neonatal period, and these served as the reference group. Seizures during the first 24 hours after birth were more likely among those infants with persistent acidemia (odds ratio, 13.0; 95% confidence interval, 6.3-26.7). The odds ratio for seizures among infants in whom acidemia developed after birth was 5.7 (95% confidence interval, 2.2-14.5). Other than the reference group, the infants who were born with acidemia that was corrected by 2 hours after birth had the lowest risk of seizures (odds ratio, 2.5; 95% confidence interval, 1.2-5.3). Significant differences in neonatal outcomes persisted after correction for anomalies. Conclusion: The direction of pH change from birth to the immediate neonatal period was significantly related to morbidity and mortality among term infants who were ill at birth or became ill shortly thereafter. (Am J Obstet Gynecol 2001;184:447-50.)

Plasma adrenomedullin levels in pregnancies with appropriate for gestational age and small for gestational age infants.

To evaluate whether maternal and fetal plasma adrenomedullin levels in pregnancies with small for gestational age (SGA) infants are different from those in pregnancies with appropriate for gestational age (AGA) infants. Maternal and fetal circulating adrenomedullin levels were compared between 62 pregnancies with AGA (43 delivered vaginally and 19 delivered by elective cesarean section) and 28 pregnancies with SGA (20 delivered vaginally and 8 delivered by elective cesarean section) at birth. Plasma adrenomedullin levels were measured from maternal and cord venous blood samples using a radioimmunoassay. Umbilical artery blood pH was also measured. There were no significant differences for maternal total adrenomedullin levels, mature adrenomedullin levels, and its ratio among the groups. There were also no significant differences for fetal total adrenomedullin levels, mature adrenomedullin levels, and its ratio among the groups. In the AGA group delivered vaginally, fetal mature/total adrenomedullin ratio (mean +/- standard error, 16.6 +/- 0.7%) was significantly higher than the maternal ratio (13.8 +/- 0.6%) (p < 0.05). In the SGA group delivered vaginally, fetal mature/total adrenomedullin ratio (18.5 +/- 1.0%) was also significantly higher than the maternal ratio (14.5 +/- 0.6%) (p < 0.05). There was no significant difference in umbilical artery blood pH among the groups. These results suggest that maternal and fetal plasma circulating adrenomedullin levels may play a role in maternal and fetal cardiovascular adaptation during delivery in pregnancies with both AGA and SGA infants.

Is intrapartum vibroacoustic stimulation an effective predictor of fetal acidosis?

The hypothesis of this prospective study is that intrapartum vibroacoustic stimulation (VAS) is an effective predictor of fetal acidosis during labor. Various clinical conditions, such as term versus preterm gestation, first stage versus second stage of labor, and fetal heart rate (FHR) variable decelerations versus late decelerations will be tested. During the study period, 113 patients were studied prospectively in either active phase of first stage (n = 53) or during the second stage of labor (n = 60). They were selected from cases exhibiting moderate to severe FHR variable decelerations or late decelerations. The fetuses of study subjects received a VAS for three seconds and FHR changes were recorded. Fetal scalp blood pH or umbilical arterial blood pH was obtained within 15 minutes of VAS. The relationship between FHR responses to VAS and fetal blood pH in term and preterm gestations, the relationship of two tests (VAS and fetal blood pH) to type of FHR decelerations, and the predictability of neonatal morbidity by two tests were analyzed. Where appropriate, Fisher's exact test (p < 0.05 was considered statistically different) and the odd ratio with 95% confidence intervals were used for statistical analyses. Excellent association between acceleration response to VAS and pH > or = 7.20, and between a negative response to VAS (no acceleration or decelerations) and pH < 7.20 were found in the first stage of labor, the second stage of labor, and the combination of both stages together (p = 0.0001, OR = 10.6 [3.3-34.0]). It was observed that negative VAS responses for predicting fetal acidosis (pH < 7.20) were comparable between term (> or = 37 weeks) and preterm (< 37 weeks, > or = 34 weeks) fetuses. Since the preterm fetuses enrolled in the study were limited in number, it is difficult to draw adequate conclusions. The positive predictive value (PPV) of fetal acidosis was 67% in both groups of FHR variable decelerations and late decelerations, but the false negative rate of acceleration VAS response for predicting no acidosis was significantly higher in the group of late decelerations (29% vs 8%, p = 0.034). Finally, both a negative VAS response and fetal acidosis (pH < 7.20) have equal predictability for neonatal morbidity. The PPV of NICU admission by a negative VAS response was two times higher than that of fetal acidosis (PPV = 61% vs 29%, p = 0.038). We found that intrapartum VAS was an effective predictor of fetal acidosis in cases of FHR variable decelerations, but its predictability for fetal acidosis in cases of FHR late decelerations was limited. Both VAS and fetal blood pH are good predictors of neonatal morbidity.

Circulatory, respiratory and behavioral responses in isoflurane anesthetized llamas

ObjectivesTo evaluate the circulatory, respiratory and behavioral effects of isoflurane (ISO) anesthesia in llamas during mechanical ventilation and spontaneous breathing. DesignProspective randomised study. AnimalSix adult, neutered male llamas (10 ± 1 years [mean ± SD], 179 ± 32 kg). Materials and methodsAnimals in which the minimum alveolar concentration (MAC) had been previously determined were anesthetized with ISO in oxygen. Inspired and end-tidal (ET) ISO were sampled continuously. Arterial blood pH, respiratory and circulatory variables, and clinical signs of anesthesia were recorded at three doses (1.0, 1.5 and 2.0 times the individual animal's MAC; mean MAC value 1.13%) of ISO during spontaneous and controlled ventilation. A series of Latin squares was used to determine order of dose. Controlled ventilation (CV) (target PaCO2 38 ± 5 mm Hg [5.0 ± 0.6 kPa]) preceded spontaneous ventilation (SV) at each dose. Animals breathed spontaneously for approximately 10 minutes prior to data collection. Body temperature was maintained at 37 ± 0.6 °C. Circulatory and respiratory data were analysed with a mixed model, least squares analysis of variance, for repeated measures taken at equally spaced intervals. p < 0.05. ResultsDose and mode of ventilation had significant influences on measured variables. For example, heart rate increased as dose increased; 67 ± 14 beats minute−1 at 1.0 MAC-CV versus 77 ± 6 beats minute−1 at 2 MAC-CV. Conversely, mean arterial pressure decreased with increasing dose; 82 ± 13 mm Hg at MAC-CV versus 52 ± 15 mm Hg at 2 MAC-CV. Arterial CO2 increased with increasing dose during SV; 45 ± 5 mm Hg [6 ± 0.6 kPa] at MAC versus 53 ± 4 mmHg [7 ± 0.5 kPa] at 2 MAC. Reflex activity (e.g. palpebral reflex) and muscle tone (e.g. jaw tone) decreased while eyelid aperture increased with increasing anesthetic dose. Conclusions and Clinical RelevanceThe influence of ISO dose and mode of ventilation on circulatory and respiratory variables in llamas is qualitatively similar to that reported in other species. Changes in reflex activity and muscle tone may be used to guide appropriate anesthetic delivery in ISO-induced llamas.

Late Second-Trimester Nonstress Test Characteristics in Preterm Delivery before 32 Weeks of Gestation

Objective: To clarify electronic fetal heart rate (FHR) monitoring characteristics in pregnancies with preterm delivery before 32 weeks of gestation, using the late second-trimester nonstress test. Methods: Among 953 children born from 1993 to 1996, we identified 100 singleton infants born before 32 weeks of gestation in whom second-trimester (24–27 weeks of gestation) electronic fetal monitoring (EFM) records were obtained. Individual components of the FHR patterns [baseline rate, baseline FHR variability, presence of acceleration (at least 10 beats/min for at least 10 s) and periodic or episodic deceleration (at least 25 beats/min for at least 15 s)] and birth characteristics were compared between pregnancy with or without second-trimester decelerations. Results: Among 100 infants, 65 had and 35 did not have second-trimester decelerations. There were no significant differences in gestational age at birth, birth weight, cord arterial blood pH, Apgar score and meconium staining between pregnancies with second-trimester decelerations and those without second-trimester decelerations. There were no significant differences in baseline rate and baseline variability between pregnancies with or without second-trimester decelerations. The number of accelerations in pregnancies with second-trimester decelerations was significantly more frequent than that in pregnancies without second-trimester decelerations (p < 0.001). There was a significant increase in the occurrence of premature rupture of the membranes (PROM; 60.0%) in pregnancies with second-trimester decelerations, when compared with events (37.1%) related to pregnancies without second-trimester decelerations (p < 0.05). There were no significant differences in the onset of breech presentation, cervical incompetency, preeclampsia and abnormal FHR pattern at birth between pregnancies with second-trimester decelerations and those without second-trimester decelerations. Pregnancies with PROM after second-trimester EFM were significantly more likely to have second-trimester decelerations than those without PROM (75.0 vs. 54.2%, p < 0.05). Conclusion: Periodic or episodic decelerations during late second-trimester EFM were associated with an increased risk of the occurrence of PROM in pregnancies with preterm delivery before 32 weeks of gestation.

Clinical, urodynamic and endoscopic characteristics of the stanford pouch ileal neobladder constructed with absorbable staples.

The clinical, urodynamic and endoscopic aspects of the Stanford pouch ileal neobladder formed with absorbable staples were investigated. A Stanford pouch ileal neobladder was formed using absorbable staples after radical cystoprostatectomy in 30 male patients with the diagnosis of muscle invasive carcinoma of the bladder between 1995 and 1998. The mean age of the patients was 62 (range 41-70) years. Patients were followed with arterial blood gas, serum biochemistry, pouch cystography, urodynamic tests and endoscopy. Five (16.7%) patients had early postoperative complications and three were related to the neobladder. One year postoperatively, low grade (I, II) vesicoureteral reflux was present in five (16.7%) cases. The mean preoperative and 6 months postoperative serum creatinine levels were 1.07+/-0.3 mg/dL and 1.2+/-0.4 mg/dL, respectively, but the difference was not statistically significant (P=0.1). Six months postoperatively the mean serum chloride level was 109+/-4.5 (range 100-113) mmol/L and the mean arterial blood pH was 7.37+/-0.2 (range 7.3-7.4). Two (6.7%) patients required oral alkaline supplementation because of high chloride levels. All the patients except one were continent throughout the day after 1 year. However, nocturnal enuresis was present in 25 (83.3%) cases. The pouch capacity was increased gradually up to 12 months postoperatively and the mean pouch capacity 12 months postoperatively was 460+/-95.8mL. Micturition occurred spontaneously in most patients while some needed abdominal straining. None of the patients had a residual urine of more than 60 mL. The mean maximum flow rate 6 months postoperatively was 9.8 (range 5.4-15.0) mL/s. After 6 months the stapled edge was noticed as a nodular line. One year postoperatively only a white scar could be observed at the suture line. The Stanford pouch ileal neobladder constructed using absorbable staples was able to provide a good capacity low pressure reservoir with a low rate of complications.

Glycyl-glutamine inhibits the respiratory depression, but not the antinociception, produced by morphine.

Glycyl-glutamine (Gly-Gln; beta-endorphin(30-31)) is an endogenous dipeptide that is synthesized through the posttranslational processing of beta-endorphin in brain stem regions that control respiration and autonomic function. This study tested the hypothesis that Gly-Gln administration to conscious rats will prevent the respiratory depression caused by morphine without affecting morphine antinociception. Rats were administered Gly-Gln (1-100 nmol) or saline (10 microl) intracerebroventricularly followed, 5 min later, by morphine (40 nmol icv). Arterial blood gases and pH were measured immediately before Gly-Gln and 30 min after morphine injection. Gly-Gln pretreatment inhibited morphine-induced hypercapnia, hypoxia, and acidosis significantly. The response was dose dependent and significant at Gly-Gln doses as low as 1 nmol. In contrast, Gly-Gln (1-300 nmol) had no effect on morphine-evoked antinociception in the paw withdrawal test. When given alone to otherwise untreated animals, Gly-Gln did not affect nociceptive latencies or blood gas values. These data indicate that Gly-Gln inhibits morphine-induced respiratory depression without compromising morphine antinociception.

Waterbirths: A Comparative Study

Background: Waterbirths were introduced in 1991 as part of a new birth concept which consisted of careful monitoring and birth management, restrictive use of invasive methods and free choice of different birth methods. Methods: After the introduction of this new birth concept a prospective observational study was initiated. All parturients of the region give birth in our clinic without preselection, ours being the only birth clinic of the region. 2% of the parturients will be referred to a larger birth clinic (university clinic) mainly because of preterm births before the end of the 33rd week of pregnancy. Every one of the 7,508 births between November 1991, and May 21, 1997, was analyzed. In this article the birth parameters of mother and child in the most often chosen spontaneous birth methods will be compared to assess the safety of alternative birth methods in general and of waterbirths in particular. 2,014 of these 5,953 spontaneous births were waterbirths, 1,108 were Maia-birthing stool births and 2,362 bedbirths (vacuum extractions not included). Results: The parity and age of the mother as well as the newborn’s birth weight are comparable in all 3 groups: waterbirth, Maia-birthing stool, and bedbirths. An episiotomy was performed in only 12.8% of the births in water, in 27.7% of the births on the Maia-birthing stool and in 35.4% of the bedbirths. These differences are statistically significant. In spite of the highest episiotomy rates, the bedbirths also show the highest 3rd- and 4th-degree laceration rates (4.1%), thus the difference between the rates for bedbirths and alternative births methods for severe lacerations is significant. The mothers’ blood loss is the lowest in waterbirths. Fewer painkillers are used in waterbirths and the experience of birth itself is more satisfying after a birth in water. The average arterial blood pH of the umbilical cord as well as the Apgar scoring at 5 and 10 min are significantly higher after waterbirths. Infections of the neonate do not occur more often after waterbirths. No case of water aspiration or any other perinatal complication of the mother or child which might be water-related was reported. Conclusion: Waterbirths and other alternative forms of birthing such as Maia-birthing stool do not demonstrate higher birth risks for the mother or the child than bedbirths if the same medical criteria are used in the monitoring as well as in the management of birth.