Arterial Blood pH Research Articles

Acute Electrolyte and Acid-Base Disorders in Patients With Ileostomies: A Case Series

Patients with ileostomies are well known to be susceptible to extracellular fluid volume depletion as a result of fluid and solute losses that are greater than intake. However, electrolyte and acid-base disorders accompanying these episodes of volume depletion are not well delineated. Case series. 7 patients with hospitalization because of acute acid-base disturbances at an academic medical center. In all patients, serum and urine creatinine and electrolytes were measured. In 2 patients, arterial blood pH and Pco(2) and ileal drainage electrolytes also were measured. 2 patients presented with severe metabolic alkalosis, and the remaining 5 patients had low serum total carbon dioxide values in association with hyperkalemia. All 7 had acute renal failure. Pathophysiological characteristics, diagnosis, and management of these disorders are discussed, along with considerations for long-term management of fluid and electrolyte balance. This report illustrates electrolyte and acid-base disorders encountered in patients with ileostomies from our clinical experience. We have no data about the incidence of these disorders. Patients with ileostomies can develop diverse and potentially life-threatening acute electrolyte and acid-base disorders when ileostomy drainage increases. Either metabolic acidosis or metabolic alkalosis can occur, depending on the nature and duration of the losses. These cases emphasize the need to be aware of the variety of acute electrolyte and acid-base disorders that can occur in this group of patients and to intervene rapidly when they develop.

Development of epilepsy in newborns with moderate hypoxic-ischemic encephalopathy and neonatal seizures

Background: Hypoxic-ischemic encephalopathy (HIE) is one of the most frequent causes of neonatal death or neurological handicaps such as cerebral palsy, mental delay, and epilepsy. Moreover, an acute consequence of HIE are neonatal seizures which can cause an additional brain damage. The neurodevelopmental outcome is known in the mild or severe cases of HIE, but in the moderate conditions the predictivity results, to date, unsatisfying. Objective: The purpose of this prospective study was to appraise the development of post-neonatal epilepsy in a cohort of term infants with moderate HIE and neonatal seizures. Methods: This study considered all newborns admitted to Neonatal Intensive Care Unit of the University of Parma between January 2000 and December 2002 for perinatal asphyxia, then followed by Neonatal Neurology Service. In all patients, neonatal variables such as type of delivery, birth weight, gestational age, Apgar scores, the need for resuscitation and assisted ventilation soon after birth, and arterial-blood pH were analyzed. Results: Ninety-two newborns were enrolled in the study because of perinatal asphyxia. Of these, 27 subjects developed mild HIE, 25 moderate, and five severe HIE. Neonatal seizures were present in 13 subjects with moderate HIE and in all newborns with severe HIE. At the last follow-up, only three infants belonging to patients with severe HIE developed epilepsy. Conclusion: Moderate HIE seems not to be related to post-neonatal epilepsy either if associated or not with neonatal seizures.

Hypertonic Resuscitation Improves Neuronal and Behavioral Outcomes after Traumatic Brain Injury plus Hemorrhage

: Resuscitation with hypertonic saline or hypertonic saline plus l-arginine acutely improves cerebral blood flow after traumatic brain injury (TBI) followed by hemorrhagic hypotension. The authors investigated whether hypertonic saline or hypertonic l-arginine would improve long-term neuronal survival and behavioral outcomes 15 days after TBI and hemorrhagic hypotension. : Mean arterial pressure, arterial blood gases, pH, plasma glucose, hematocrit, and hemoglobin were measured in male Sprague-Dawley rats before and after moderate (2.0 atm) fluid percussion TBI. Rats were assigned to one of six groups: (1) sham TBI, (2) hemorrhage only, (3) TBI only, (4) TBI plus hemorrhage and resuscitation with 0.9% saline, (5) TBI plus hemorrhage and resuscitation with hypertonic saline (7.5%), or (6) TBI plus hemorrhage and resuscitation with l-arginine (100 mg/kg) in hypertonic saline. On postinjury days 1-5, vestibulomotor function was assessed using beam balance and beam walking tasks. On postinjury days 11-15, spatial memory function was assessed using the Morris water maze. After behavioral testing, neuronal counting was performed bilaterally on specific hippocampal regions. : Groups receiving hypertonic saline (P < 0.05, day 15 vs. day 11) or hypertonic l-arginine (P < 0.05, days 13-15 vs. day 11) showed improved performance over time on the Morris water maze, as well as significantly improved neuronal survival in the contralateral hippocampus (P < 0.05, hypertonic saline or hypertonic l-arginine vs. normal saline) compared with untreated TBI or normal saline-treated TBI plus hemorrhage groups. : Hypertonic saline and hypertonic l-arginine were both effective at promoting long-term neuronal survival and behavioral recovery. The slightly earlier improvement in Morris water maze performance in the hypertonic l-arginine group warrants further studies to determine whether higher doses of l-arginine provide additional improvement. This study supports the therapeutic benefits of hypertonic resuscitation after TBI plus hemorrhagic hypotension.

Editor’s Choice

Editor’s Choice

Bicarbonate Therapy in Severe Metabolic Acidosis

The utility of bicarbonate administration to patients with severe metabolic acidosis remains controversial. Chronic bicarbonate replacement is obviously indicated for patients who continue to lose bicarbonate in the ambulatory setting, particularly patients with renal tubular acidosis syndromes or diarrhea. In patients with acute lactic acidosis and ketoacidosis, lactate and ketone bodies can be converted back to bicarbonate if the clinical situation improves. For these patients, therapy must be individualized. In general, bicarbonate should be given at an arterial blood pH of < or =7.0. The amount given should be what is calculated to bring the pH up to 7.2. The urge to give bicarbonate to a patient with severe acidemia is apt to be all but irresistible. Intervention should be restrained, however, unless the clinical situation clearly suggests benefit. Here we discuss the pros and cons of bicarbonate therapy for patients with severe metabolic acidosis.

A comparison of equine recovery characteristics after isoflurane or isoflurane followed by a xylazine–ketamine infusion

ObjectiveTo determine whether infusion of xylazine (XYL) and ketamine (KET) for 30 minutes after isoflurane administration in horses would result in improved quality of recovery from anesthesia, without detrimental cardiopulmonary changes. Study designRandomized, blinded experimental trial. AnimalsSeven healthy adult horses aged 6.4 ± 1.9 years and weighing 506 ± 30 kg. MethodsHorses were anesthetized twice, at least 1 week apart. On both occasions, anesthesia was induced by the administration of XYL, diazepam, and KET, and maintained with isoflurane for approximately 90 minutes, the last 60 minutes of which were under steady-state conditions (1.2 times the minimum alveolar concentration isoflurane). On one occasion, horses were allowed to recover from isoflurane anesthesia, while on the other, XYL and KET were infused for 30 minutes after termination of isoflurane administration. Heart rate, respiratory rate, arterial blood pressure, pH, and blood-gases were measured and recorded at set intervals during steady-state isoflurane anesthesia and XYL–KET infusion. Recovery events were timed and subjectively scored by one nonblinded and two blinded observers. Data were analyzed using a restricted maximum likelihood-based mixed effect model repeated measures analysis. ResultsInfusion of XYL and KET resulted in longer recovery times, but there was no significant improvement in recovery quality score. ConclusionsUnder the conditions of this study, infusion of XYL and KET does not positively influence recovery from isoflurane anesthesia in horses. Clinical relevanceThis study does not support the routine use of XYL and KET infusions in horses during the transition from isoflurane anesthesia to recovery.

Treatment of Premature Calves with Clinically Diagnosed Respiratory Distress Syndrome

Respiratory distress syndrome (RDS) has been reported previously in premature calves. However, there have been no published data on the effect of surfactant replacement therapy in the treatment of premature calves with RDS. Surfactant replacement therapy added to the standard treatment for premature calves clinically diagnosed with RDS would increase the viability of the calves. Twenty-seven premature calves with clinically diagnosed RDS. Twenty calves were instilled intratracheally with bovine lung surfactant extract and provided with standard treatment for RDS (surfactant group). Seven calves were given only standard care for RDS without surfactant therapy and placed in the control group. Standard treatment for newborn calves with RDS includes warming, administration of intranasal oxygen, fluid replacement, administration of antibiotics, and immunoglobulin solution. Arterial blood samples were collected from the calves at 3 observation points, the first just before treatment (hour 0) and at 2 hours (hour 2) and 24 hours (hour 24) after treatment was started to determine if ventilation was adequate, improving, or deteriorating. Blood gases, pH, bicarbonate, and lactate concentrations were measured. In the surfactant group, mean partial pressure of oxygen significantly increased at hours 2 and 24. Mean partial pressure of carbon dioxide decreased and mean arterial blood pH increased at hour 24 in the surfactant group compared with the control group (P < .05). Of the 20 calves in the surfactant group, 12 survived and 8 died. All 7 calves in the control group died. The results of this study suggest that surfactant replacement therapy may reduce neonatal deaths in premature calves with clinically diagnosed RDS.

17-Hydroxyprogesterone in premature infants as a marker of intrauterine stress

Amniotic infection (AI) and preeclampsia (PE), which are commonly the reason for prematurity, inflict stress of different duration on immature fetuses. Whether chronic stress, as reflected by intrauterine growth retardation, influences the level of 17-OH progesterone (17-OHP), was not previously examined. We analyzed 17-OHP and TSH levels during neonatal screenings in the first hours of life of 90 premature infants born between 25 and 33 weeks of gestation in infants with AI (n=37) or with PE (n=53). Control of acute stress parameters was derived from umbilical arterial cord blood pH and base excess (BE). Mean 17-OHP levels of infants born to mothers with PE were 85.7 nmol/L compared to 54.6 nmol/L (P<0.001) in AI infants. 17-OHP was even higher when intrauterine growth restriction was present (99.8 nmol/L). Antenatal steroids and mode of delivery did not significantly affect 17-OHP levels. Stress of relatively long duration, as in cases of PE, leads to a significant increase of 17-OHP level in preterm infants. The postnatal 17-OHP level may be considered as a measure for severity of intrauterine stress and might be used as an individualized indicator for earlier intensive care.

Relationships between umbilical cord arterial blood pH levels at delivery and Bayley Psychomotor Development Index scores in early childhood

To correlate data on umbilical cord arterial blood pH (pHa) levels obtained at delivery with subsequent Bayley Psychomotor Development (PDI) scores determined on the same cohort of children at age 18 months. At delivery, we obtained umbilical cord bloods for pHa levels along with other biological parameters. Following the birth cohort prospectively, at age 18 months we did a comprehensive, blinded neurodevelopmental examination to determine a PDI score for each child. Over the broad range of umbilical cord arterial blood pH levels from 7.03 to 7.52, no statistically significant correlation (Pearson correlation coefficient, -0.016, P=0.88) was found between pHa at delivery and PDI scores at age 18 months. To study our finding in greater detail, we formed a subset of the data consisting only of lower pHa levels at delivery (defined as <or=7.20) and subsequent PDI scores. In this data subset, we again found that no significant relationship existed (Pearson correlation coefficient, +0.003, P=0.99). Our findings are consistent with the evolving hypothesis that adverse neurological outcomes in children often have etiologies other than intrapartum fetal acidemia.

Fetal electrocardiographic monitoring during labor in relation to cord blood levels of the brain-injury marker protein S-100

Cord artery protein S-100 levels at birth are potential markers of brain damage after asphyxia. Our aim was to investigate if S-100 levels were elevated in neonates with indirect signs of asphyxia during birth. S-100 levels in cord blood were studied in relation to cardiotocography (CTG) and fetal electrocardiography (FECG) changes during birth and to acidemia in umbilical blood. This case-control study was performed in parallel to a large randomized controlled trial (RCT) studying FECG at birth. Protein S-100 samples were collected from 103 neonates at birth and related to the CTG and ECG changes during labor and to pH in umbilical blood. Protein S-100 was significantly higher in neonates with umbilical artery blood pH<or=7.05, compared to neonates with pH>7.05. Furthermore, neonates with preterminal CTG patterns showed increased S-100 levels compared to neonates with normal CTG. Neonates having significant CTG and ECG changes, leading to intervention according to clinical guidelines, showed significantly higher S-100 levels compared to neonates without such indication of intervention. A relation exists between S-100 in umbilical blood at birth, acidosis and pathological patterns in CTG and FECG during labor.

Umbilical cord blood lactate: A valuable tool in the assessment of fetal metabolic acidosis

Objective The aim of the present study was (1) to evaluate the relationship between umbilical cord arterial blood lactate and pH, standard base excess (SBE), and actual base excess (ABE) at delivery and (2) to suggest a cut-off level of umbilical cord arterial blood lactate in predicting fetal asphyxia using ROC-curves, where an ABE value less than −12 was used as “gold standard” for significant intrapartum asphyxia. Study design This is a descriptive study of umbilical cord arterial blood samples from 2554 singleton deliveries. The deliveries took place at the Department of Obstetrics and Gynaecology, Hvidovre University Hospital, Copenhagen, Denmark where umbilical cord blood sampling and blood gas analysis is part of the routine assessment of all newborns. Results We found significant correlations between lactate and pH ( r = −0.73), lactate and SBE ( r = −0.76), and lactate and ABE ( r = −0.83). ROC-curves suggested a lactate cut-off level of 8 mmol/l for indicating intrapartum asphyxia. Conclusion Lactate in arterial umbilical cord blood might be a more direct and accordingly more correct indicator of fetal asphyxia at delivery than pH and SBE (or ABE). Its potential as a predictor of neonatal outcome needs to be evaluated in future studies.

Comparison of the effects of caffeine and doxapram on respiratory and cardiovascular function in foals with induced respiratory acidosis

To determine and compare the effects of caffeine and doxapram on cardiorespiratory variables in foals during isoflurane-induced respiratory acidosis. 6 clinically normal foals (1 to 3 days old). At intervals of > or = 24 hours, foals received each of 3 IV treatments while in a steady state of hypercapnia induced by isoflurane anesthesia (mean +/- SD, 1.4 +/- 0.3% endtidal isoflurane concentration). After assessment of baseline cardiorespiratory variables, a low dose of the treatment was administered and variables were reassessed; a high dose was then administered, and variables were again assessed. Sequential low- and high-dose treatments included doxapram (loading dose of 0.5 mg/kg, followed by a 20-minute infusion at 0.03 mg/kg/min and then 0.08 mg/kg/min), caffeine (5 mg/kg and 10 mg/kg), and saline (0.9% NaCl) solution (equivalent volumes). Administration of doxapram at both infusion rates resulted in a significant increase in respiratory rate, minute ventilation, arterial blood pH, PaO(2), and arterial blood pressure. These variables were also significantly higher during doxapram administration than during caffeine or saline solution administration. There was a significant dose-dependent decrease in PaCO(2) and arterial bicarbonate concentration during doxapram treatment. In contrast, PaCO(2) increased from baseline values after administration of saline solution or caffeine. The PaCO(2) value was significantly lower during doxapram treatment than it was during caffeine or saline solution treatment. Results indicated that doxapram restored ventilation in a dose-dependent manner in neonatal foals with isoflurane-induced hypercapnia. The effects of caffeine on respiratory function were indistinguishable from those of saline solution.

Closed‐loop feedback computer‐controlled infusion of phenylephrine for maintaining blood pressure during spinal anaesthesia for caesarean section: a preliminary descriptive study*

We describe the novel use of a closed-loop feedback computer-controlled infusion of phenylephrine for maintaining blood pressure in 53 patients having spinal anaesthesia for elective caesarean section. A simple on-off algorithm was used that activated an intravenous phenylephrine infusion at 100 microg.min(-1) when systolic blood pressure was less than or equal to baseline and stopped the infusion when systolic blood pressure exceeded baseline. Up to uterine incision, 94.6% of all systolic blood pressure measurements were within the range (baseline +/- 20%). Seven patients (13.2%) had one or more episodes of hypotension (systolic blood pressure < 80% of baseline) and 23 patients (37.7%) had one or more episodes of hypertension (systolic blood pressure > 120% of baseline). No patient had nausea or vomiting and in no case was umbilical arterial blood pH < 7.2. Calculated system performance parameters were comparable with those of previously published closed-loop systems and provide a reference for the potential development and comparison of more advanced algorithms.

The cardiopulmonary effects of dobutamine and norepinephrine in isoflurane-anesthetized foals

ObjectiveTo evaluate the cardiovascular effects of norepinephrine (NE) and dobutamine (DB) in isoflurane-anesthetized foals. Study designProspective laboratory study. MethodsNorepinephrine (0.05, 0.10, 0.20, and 0.40 μg kg−1 minute−1) and dobutamine (2.5, 5.0, and 10 μg kg−1 minute−1) were alternately administered to seven healthy, 1- to 2-week-old isoflurane-anesthetized foals. Arterial and pulmonary arterial blood pressure, right atrial pressure, pulmonary artery occlusion pressure, heart rate, body temperature, cardiac output, arterial and mixed venous blood pH, partial pressure of carbon dioxide, partial pressure of oxygen [arterial partial pressure of oxygen (PaO2) and mixed venous partial pressure of oxygen (P v¯O2)], and packed cell volume were measured. Standard base excess, bicarbonate concentration, systemic and pulmonary vascular resistance, cardiac index (CI), stroke volume, left and right stroke work indices, oxygen delivery ( D˙O2), consumption, and extraction were calculated. ResultsNorepinephrine infusion resulted in significant increases in arterial and pulmonary arterial pressure, systemic and pulmonary vascular resistance indices, and PaO2; heart rate was decreased. Dobutamine infusion resulted in significant increases in heart rate, stroke volume index, CI, and arterial and pulmonary arterial blood pressure. Systemic and pulmonary vascular resistance indices were decreased while the ventricular stroke work indices increased. The PaO2 decreased while D˙O2 and oxygen consumption increased. Oxygen extraction decreased and P v¯O2 increased. Conclusions and Clinical relevanceNorepinephrine primarily augments arterial blood pressure while decreasing CI. Dobutamine primarily augments CI with only modest increases in arterial blood pressure. Both NE and DB could be useful in the hemodynamic management of anesthetized foals.

Widening of the QRS Complex Due to Severe Hyperkalemia as an Acute Complication of Diabetic Ketoacidosis

n 18-year-old man was referred to the Emergency epartment after a 3-day history of nausea, vomiting, uscular weakness, and stomach pain. He had been iagnosed with type 1 diabetes a year prior. On admision he was afebrile, disoriented to place and time, and everely dehydrated, with Kussmaul’s respiration at 35 reaths/min, pulse 120 beats/min, and blood pressure 0/40 mm Hg. His chest examination was clear to ausultation, and cardiac examination was notable for a egular tachycardia at 120 beats/min. The abdomen was oft and non-tender and examination revealed normal owel sounds with no palpable abdominal mass or orgaomegaly. The serum glucose concentration was 34.3 mol/L, the arterial blood pH was 7.21, base excess 19.9, and the serum potassium concentration was 9.1 mol/L. The diagnosis of diabetic ketoacidosis was ade. He responded to standard hydration therapy, inravenous insulin infusion on a sliding scale regimen started at 6 U/h), sodium bicarbonate, and calcium gluonate. He was able to resume oral intake 2 days later nd was stabilized on subcutaneous insulin. The initial electrocardiogram (ECG) revealed absence f P-waves, widening of the QRS complexes (0.16 s), nd tall peaked symmetrical T-waves in leads I, VL,

Extracorporeal Membrane Oxygenation to Aid Cardiopulmonary Resuscitation in Infants and Children

Extracorporeal membrane oxygenation (ECMO) has been used to support cardiorespiratory function during pediatric cardiopulmonary resuscitation (CPR). We report on outcomes and predictors of in-hospital mortality after ECMO used to support CPR (E-CPR). Outcomes for patients aged <18 years using E-CPR were analyzed with data from the Extracorporeal Life Support Organization, and predictors of in-hospital mortality were determined. Of 26,242 ECMO uses reported, 695 (2.6%) were for E-CPR (n=682 patients). Survival to hospital discharge was 38%. In a multivariable model, pre-ECMO factors such as cardiac disease (odds ratio [OR] 0.51, 95% confidence interval [CI] 0.31 to 0.82) and neonatal respiratory disease (OR 0.28, 95% CI 0.12 to 0.66), white race (OR 0.65, 95% CI 0.45 to 0.94), and pre-ECMO arterial blood pH >7.17 (OR 0.50, 95% CI 0.30 to 0.84) were associated with decreased odds of mortality. During ECMO, renal dysfunction (OR 1.89, 95% CI 1.17 to 3.03), pulmonary hemorrhage (OR 2.23, 95% CI 1.11 to 4.50), neurological injury (OR 2.79, 95% CI 1.55 to 5.02), CPR during ECMO (OR 3.06, 95% CI 1.42 to 6.58), and arterial blood pH <7.2 (OR 2.23, 95% CI 1.23 to 4.06) were associated with increased odds of mortality. ECMO used to support CPR rescued one third of patients in whom death was otherwise certain. Patient diagnosis, absence of severe metabolic acidosis before ECMO support, and uncomplicated ECMO course were associated with improved survival.

Perinatal pH and Neuropsychological Outcomes at Age 3 Years in Children Born Preterm: An Exploratory Study

The impact of extreme prematurity and related hypoxic-ischemic events on brain development recently has begun to be characterized with modern neuroimaging methods, although comparatively less is known about the neuropathology in those born at heavier birth weights. Even subclinical levels of perinatal hypoxia-ischemia, as indexed by perinatal blood pH, are related to intelligence in school-aged children born preterm. Given the impact of hypoxia-ischemia on white matter and the emerging evidence of specific executive and mathematic deficits in children born preterm, the impact of perinatal hypoxia-ischemia on these outcomes was explored in children at relatively low-risk for sequelae. In a sample of 22 preschool children born preterm, arterial blood pH values obtained within the first 3 h of life were abstracted from review of hospital medical charts, and then related to specific cognitive task performance at age 3 years. Mean initial pH was in the normal to subclinical range. Initial pH appears to be a strong predictor of specific mathematics and controlled attention abilities, and is not limited to general verbal ability alone. However, initial pH was not related to performance on measures of motor impulsivity or working memory. As a screening index of subtle hypoxia-ischemia, these findings suggest that perinatal arterial blood pH warrants further study as a potential marker of subtle hypoxic-ischemic injury that likely affects cognitive outcome throughout childhood in those at risk due to preterm birth.

Agreement and correlation of pH, bicarbonate, base excess and lactate measurements in venous and arterial blood of premature and term infants.

Determine the extent of agreement and correlation between arterial samples and venous (obtained from a venous umbilical catheter), with respect to measurements of pH, bicarbonate, base excess and lactate, in critically ill term and premature newborns. Arterial blood samples (0.5-1 mL) were obtained for gas analysis by radial artery puncture, and, within the limit of 5 minutes, samples were obtained from venous umbilical catheters. Bland-Altman plots were used to depict agreement between arterial and venous measurements. Limits of agreement were defined as the mean difference ± 2SD (Standard Deviation). Correlation was assessed by Pearson's method. A hundred and six samples (53 pairs) were taken from 53 patients for analysis of bicarbonate, pH and base excess. Lactate was analyzed in 49 pairs of samples. Differences were within the limits of agreement in 94.3% of pairs of samples for pH, and the same percentage was observed for bicarbonate. There was agreement in 96.2% of pairs for base excess, and in 91.8% for lactate. Mean differences were 0.03 units for pH, -1.2 mmol/L for bicarbonate, -0.24 mmol/L for base excess and 0.33 mmol/L for lactate. Pearson's correlation coefficients (r) were 0.87 for pH, 0.76 for bicarbonate, 0.86 for base excess and 0.95 for lactate. Although single venous values cannot be used as equivalent to arterial for assessing acid base status in newborns, venous blood samples can be used serially for monitoring trends over time.

Meconium-stained Amniotic Fluid—Perinatal Outcome and Obstetrical Management in a Low-Risk Suburban Population

Although the presence of meconium-stained amniotic fluid (MSAF) has in the past been viewed as a significant indicator of adverse fetal status, the great majority of infants born with MSAF are not impaired in the short or the long term. Although some studies have shown a link between MSAF, low Apgar scores, and decreased arterial cord blood pH values, many of these studies were performed over 10 years ago and included women of very specific ethnic and socioeconomic populations. Thus, their relevance to the current practice of obstetrics is unclear. The present retrospective cohort study included 11,226 deliveries taking place in the years 1998-2003 in a typical European suburban population. Each of 1123 women with MSAF-representing 10% of the study population-had a term singleton pregnancy with cephalic presentation and underwent a trial of vaginal delivery. Control women were the next to give birth without MSAF. Severe maternal disease, preeclampsia, and fetal malformations precluded participation in the study. There were no differences in Apgar scores in the MSAF and non-MSAF groups, and in both groups the mean arterial pH was 7.26. The respective rates of a 5-minute Apgar score below 6 were 0.9% and 0.4%. Obstetrical interventions were more frequent in the MSAF group. Cesarean delivery was carried out in 17.4% of the MSA group and 9.6% of the non-MSAF group, and operative vaginal delivery in 13.9% and 6.2%, respectively. Infants in the MSAF group were heavier, but to a large degree this reflected more advanced gestational age. Multivariate analysis, controlling for parity, gestational age, infant weight, maternal age, and the use of epidural analgesia and oxytocin, indicated that obstetrical interventions such as cesarean section had a significant protective effect regardless of whether or not MSAF was present. The presence of MSAF had little effect on the newborn infant during the immediate postpartum period in this low-risk population. Nevertheless, it does influence obstetrical management, possibly because of more difficult labors or a lower threshold for obstetrical intervention.

Clinical and pathological features of fat embolism with acute respiratory distress syndrome

FES (fat embolism syndrome) is a clinical problem, and, although ARDS (acute respiratory distress syndrome) has been considered as a serious complication of FES, the pathogenesis of ARDS associated with FES remains unclear. In the present study, we investigated the clinical manifestations, and biochemical and pathophysiological changes, in subjects associated with FES and ARDS, to elucidate the possible mechanisms involved in this disorder. A total of eight patients with FES were studied, and arterial blood pH, PaO(2) (arterial partial pressure of O(2)), PaCO(2) (arterial partial pressure of CO(2)), biochemical and pathophysiological data were obtained. These subjects suffered from crash injuries and developed FES associated with ARDS, and each died within 2 h after admission. In the subjects, chest radiography revealed that the lungs were clear on admission, and pulmonary infiltration was observed within 2 h of admission. Arterial blood pH and PaO(2) declined, whereas PaCO(2) increased. Plasma PLA(2) (phospholipase A(2)), nitrate/nitrite, methylguanidine, TNF-alpha (tumour necrosis factor-alpha), IL-1beta (interleukin-1beta) and IL-10 (interleukin-10) were significantly elevated. Pathological examinations revealed alveolar oedema and haemorrhage with multiple fat droplet depositions and fibrin thrombi. Fat droplets were also found in the arterioles and/or capillaries in the lung, kidney and brain. Immunohistochemical staining identified iNOS (inducible nitric oxide synthase) in alveolar macrophages. In conclusion, our clinical analysis suggests that PLA(2), NO, free radicals and pro-inflammatory cytokines are involved in the pathogenesis of ARDS associated with FES. The major source of NO is the alveolar macrophages.