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Arterial pH (arterial + ph)

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Medical Sciences	93%

Selected Abstracts

Cardiovascular effects of desflurane following acute hemorrhage in dogs

JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 1 2003
Paulo S.P. Santos DVM
Abstract Objective: To determine the cardiovascular effects of desflurane in dogs following acute hemorrhage. Design: Experimental study. Animals: Eight mix breed dogs. Interventions: Hemorrhage was induced by withdrawal of blood until mean arterial pressure (MAP) dropped to 60 mmHg in conscious dogs. Blood pressure was maintained at 60 mmHg for 1 hour by further removal or replacement of blood. Desflurane was delivered by facemask until endotracheal intubation could be performed and a desflurane expiratory end-tidal concentration of 10.5 V% was maintained. Measurements and main results: Systolic, diastolic, and mean arterial blood pressure (SAP, DAP and MAP), central venous pressure (CVP), cardiac output (CO), stroke volume (SV), cardiac index (CI), systemic vascular resistance (SVR), heart rate (HR), respiratory rate (RR), partial pressure of carbon dioxide in arterial blood (PaCO2), and arterial pH were recorded before and 60 minutes after hemorrhage, and 5, 15, 30, 45 and 60 minutes after intubation. Sixty minutes after hemorrhage, SAP, DAP, MAP, CVP, CO, CI, SV, PaCO2, and arterial pH decreased, and HR and RR increased when compared with baselines values. Immediately after intubation, MAP and arterial pH decreased, and PaCO2 increased. Fifteen minutes after intubation SAP, DAP, MAP, arterial pH, and SVR decreased. At 30 and 45 minutes, MAP and DAP remained decreased and PaCO2 increased, compared with values measured after hemorrhage. Arterial pH increased after 30 minutes of desflurane administration compared with values measured 5 minutes after intubation. Conclusions: Desflurane induced significant changes in blood pressure and arterial pH when administered to dogs following acute hemorrhage. [source]

Effect of Intravenous Albumin Infusion on Brain Salicylate Concentration

ACADEMIC EMERGENCY MEDICINE, Issue 6 2007
Steven C. Curry MD
Background:Salicylate poisoning appears to result in death, despite supportive care, once a critical brain salicylate concentration is reached. The binding of salicylate to albumin is saturable; free plasma salicylate concentrations rise disproportionately to total drug levels. Because unbound salicylate distributes into the brain, the authors questioned whether an intravenous (IV) infusion of albumin would cause a redistribution of salicylate from the brain back into the plasma, which might allow enough time for hemodialysis to be instituted. Objectives:To determine if IV albumin infusion would lower brain salicylate concentrations through redistribution in a porcine model of acute salicylate poisoning. Methods:In a randomized controlled trial, 17 swine under anesthesia and controlled ventilation received 400 mg/kg of sodium salicylate IV over 15 minutes. At 60 minutes, nine animals received 1.25 g/kg albumin (25% solution) IV over 15 minutes, while eight control animals received an equal volume of normal saline (5 mL/kg). Arterial pH was maintained between 7.45 and 7.55. Serial measurements of serum albumin as well as free and total salicylate concentrations were obtained, and urine was collected for measurement of total salicylate excretion. At 180 minutes, animals were killed and brains harvested for measurement of brain salicylate concentrations. Results:Average peak serum total salicylate concentrations of 105.5 and 109 mg/dL were achieved in control and albumin-treated animals, respectively. Albumin infusion was accompanied by statistically significant increases in serum total salicylate concentrations (median from 79.5 to 86.9 mg/dL at 75 minutes), while levels decreased slightly in control animals. Serum free salicylate concentrations decreased slightly in albumin-treated animals, but the difference was not statistically significant. Median brain salicylate concentrations were about 14% lower in the albumin treatment group (17.8 mg/100 g brain) compared with controls (20.5 mg/100 g brain); this approached statistical significance (p = 0.075). Median urinary salicylate excretion was higher in the albumin-treated group (0.83 vs. 0.48 g; p = 0.072), with similar urinary pH and volumes in both groups. Conclusions:In this animal model of salicylate poisoning, IV infusion of 1.25 g/kg albumin was accompanied by a 14% decline in median brain salicylate concentrations, which approached statistical significance. [source]

The case for venous rather than arterial blood gases in diabetic ketoacidosis

EMERGENCY MEDICINE AUSTRALASIA, Issue 1 2006
Anne-Maree Kelly
Abstract Objectives:, For patients with diabetic ketoacidosis (DKA), arterial blood gas (BG) sampling for measurement of pH and bicarbonate has been considered an essential part of initial evaluation and monitoring of progress. There is growing evidence that venous values can be clinically acceptable alternatives to arterial measurements. This article summarizes the recent evidence regarding the validity of venous BG sampling in DKA. Methods:, Medline search for the years 1995 to present, hand search of reference lists, search of on-line evidence-based medicine sites. Results:, In patients with DKA the weighted average difference between arterial and venous pH was 0.02 pH units (95% limits of agreement ,0.009 to +0.021 pH units) and between arterial and venous bicarbonate was ,1.88 mEq/L. Conclusions:, There is reasonable evidence that venous and arterial pH have sufficient agreement as to be clinically interchangeable in patients with DKA who are haemodynamically stable and without respiratory failure. There is some evidence that venous and arterial bicarbonate also agree closely in DKA but this requires confirmation. [source]

Ventilatory control in humans: constraints and limitations

EXPERIMENTAL PHYSIOLOGY, Issue 2 2007
Susan A. Ward
Below the lactate threshold (,L), ventilation responds in close proportion to CO2 output to regulate arterial partial pressure of CO2. While ventilatory control models have traditionally included proportional feedback (central and carotid chemosensory) and feedforward (central and peripheral neurogenic) elements, the mechanisms involved remain unclear. Regardless, putative control schemes have to accommodate the close dynamic ,coupling' between and . Above ,L, is driven down to constrain the fall of arterial pH by a compensatory hyperventilation, probably of carotid body origin. When requirements are high (as in highly fit endurance athletes), can attain limiting proportions. Not only does this impair gas exchange at these work rates, but there may be an associated high metabolic cost for generation of respiratory muscle power, which may be sufficient to divert a fraction of the cardiac output away from the muscles of locomotion to the respiratory muscles, further compromising exercise tolerance. [source]

Effect of Labour and Delivery on Plasma Hepatic Enzymes in the Newborn

JOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 1 2000
Dr. Max Mongelli
Abstract Objective: To study the relationship between cord blood hepatic enzymes and obstetric and neonatal outcome in a Chinese population. Materials and Methods: The study group consisted of 288 low-risk Chinese women with singleton term pregnancies. The following enzymes were assayed in cord blood: lactate dehydrogenase (LDH), glutamyl transferase (GGT), aspartate aminotransferase (AST) and alanine transferase (ALT). These were correlated to maternal and neonatal characteristics. Results: A strong correlation was noted between cord blood AST and LDH (R = 0.582, p < 0.01), which was absent amongst those infants delivered by elective cesarean section. LDH, AST and ALT were negatively correlated with cord arterial pH and base excess (BE). GGT was inversely related only to gestational age (R = - 0.18, p < 0.01). Both LDH and AST were weakly correlated with the duration of the first and second stages of labour. LDH was most closely linked to arterial pH, whereas AST was related to both arterial BE and duration of the second stage. Conclusions: The reference values are comparable to those published for Caucasian populations. There are moderate elevations in LDH and AST associated with the onset of labour and changes in acid-base status. [source]

Evaluation of hematological, chemistry and blood gas values in dogs receiving hemoglobin glutamer-200

JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 1 2007
DACVECC, DACVIM, Marie E. Kerl DVM
Abstract Objective: To evaluate the degree of interference that administration of hemoglobin glutamer-200 (Hb-200) caused for complete blood counts (CBC), biochemical profiles, cooximetry, and point of care (POC) testing in healthy dogs. Design: Prospective, longitudinal experimental study. Setting: Veterinary medical teaching hospital. Animals: Six purpose-bred research hounds. Interventions: Dogs were administered FDA-approved hemoglobin-based oxygen carrier (Hb-200) intravenously at 7.5 mL/kg over 2 hours. Arterial and venous blood samples were obtained before administration (Time 0) and at 3, 8, 14, 26, 50, 74, 98, 122, and 146 hours following administration. Measurements and main results: No adverse health effects were observed in any of the dogs. Characteristic mucous membrane, serum, and plasma color changes occurred following administration of Hb-200. Laboratory values that were significantly lower than baseline included packed cell volume, red blood cell count, hemoglobin, hematocrit, creatinine, cholesterol, alanine aminotransferase, and alkaline phosphatase. Laboratory values that were significantly greater than baseline included mean corpuscular hemoglobin concentration, arterial pH, arterial total carbon dioxide, arterial bicarbonate, amylase, albumin, total protein, globulin, calcium, phosphorous, total bilirubin, carboxyhemoglobin, and methemoglobin. All values returned to baseline by the completion of the 146-hour monitoring period. Conclusions: In normal dogs, administration of Hb-200 resulted in statistically significant changes in multiple laboratory parameters; however, these changes are not likely to be clinically significant in the care of critically ill dogs. [source]

Cardiovascular effects of desflurane following acute hemorrhage in dogs

Lack of effect of ranitidine on gastric luminal pH and mucosal PCO2 during the first day in the ICU

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2005
S. M. Jakob
Background:, Histamine2 (H2)-blocking agents can attenuate intragastric CO2 -production by reducing gastric acid secretion and preventing the interaction between H+ and bicarbonate. However, gastric acid production may be impaired in acute circulatory failure due to poor mucosal perfusion, and H2 -blockade could further impair mucosal perfusion. Methods:, Forty patients with acute circulatory and/or respiratory failure, age 61 ± 16 years (mean ± SD), APACHE II score 21 ± 7, and SOFA score 8 ± 3, received randomly either ranitidine, 50 mg (R) or placebo (P) every 8 h. Gastric intraluminal pH (gpH; antimony probe with external reference electrode) and mucosal pCO2 (prCO2, semicontinuous air-tonometry) were measured during 24 h, and blood gases were taken at 6-h intervals. Results:, Gastric intraluminal pH was 4.3 ± 2.4 in P and 5.1 ± 1.6 in R (NS). Mean prCO2 was 6.8 ± 2.7 kPa in P and 7.4 ± 2.1 kPa in R, and mucosal-arterial pCO2 gradient (,pCO2) was 2.2 ± 2.9 kPa and 2.4 ± 2.4 kPa, respectively (NS). Within-patient variabilities of gpH and prCO2 were not influenced by ranitidine. A posthoc analysis revealed that non-survival in R was associated with a low mucosal pHi after 24 h (P = 0.002). This was explained by a low arterial pH but not by differences in gpH or prCO2. Conclusion:, In acute respiratory and circulatory failure, H2 blockade has an inconsistent impact on gpH and does not reduce variabilities of gpH or prCO2. [source]

Time to Cardiac Death After Withdrawal of Life-Sustaining Treatment in Potential Organ Donors

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 9 2009
C. Suntharalingam
Organ donation after cardiac death (DCD) is increasing markedly, allowing more patients to benefit from transplantation. The time to cardiac death following withdrawal of life-supporting treatment varies widely and is an important determinant of whether organ donation occurs. A prospective multicenter study of potential DCD donors was undertaken to evaluate the time to death and identify associated factors. One hundred and ninety-one potential adult DCD donors at nine UK centers were studied. Treatment withdrawal comprised stopping ventilator support and inotropes. Demographics and physiological variables at the time of death were recorded. Following treatment withdrawal, all potential donors died, with median time to death of 36 min (range 5 min to 3.3 days). Eighty-three potential donors (43.5%) remained alive 1 h after treatment withdrawal, and 69 (36.1%) and 54 (28.3%) at 2 and 4 h, respectively. Univariate analysis revealed that age, cause of death, ventilation mode, inotrope use, systolic blood pressure, FiO2 and arterial pH at treatment withdrawal were all associated with time to death. Multivariable analysis showed that younger age, higher FiO2 and mode of ventilation were independently associated with shorter time to death. This information may aid planning and resourcing of DCD organ recovery and help maximize DCD donor numbers. [source]

Original Article: Benefits of introducing universal umbilical cord blood gas and lactate analysis into an obstetric unit

AUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 4 2010
Christopher R.H. WHITE
Background:, Current evidence suggests that umbilical arterial pH analysis provides the most sensitive reflection of birth asphyxia. However, there's debate whether umbilical cord blood gas analysis (UC-BGA) should be conducted on some or all deliveries. Aim:, The aim of this study was to evaluate the impact of introducing universal UC-BGA at delivery on perinatal outcome. Methods:, An observational study of all deliveries ,20 weeks' gestation at a tertiary obstetric unit between January 2003 and December 2006. Paired UC-BGA was performed on 97% of deliveries (n = 19,646). Univariate and adjusted analysis assessed inter-year UC-BGA differences and the likelihood of metabolic acidosis and nursery admission. Results:, There was a progressive improvement in umbilical artery pH, pO2, pCO2, base excess and lactate values in univariate and adjusted analyses (P < 0.001). There was a significant reduction in the newborns with an arterial pH <7.10 (OR = 0.71; 95%CI 0.53,0.95) and lactate >6.1 mmol/L (OR = 0.37; 95%CI 0.30,0.46). Utilising population specific 5th and 95th percentiles, there was a reduction in newborns with arterial pH less than 5th percentile (pH 7.12; OR = 0.75; 95%CI 0.59,0.96) and lactate levels greater than 95th percentile (6.7 mmol/L; OR = 0.37; 95%CI 0.29,0.49). There was a reduction in term (OR = 0.65; 95%CI 0.54,0.78), and overall (OR = 0.75; 95%CI 0.64,0.87) nursery admissions. These improved perinatal outcomes were independent of intervention rates. Conclusions:, These data suggest that introduction of universal UC-BGA may result in improved perinatal outcomes, which were observed to be independent of obstetric intervention. We suggest that these improvements might be attributed to provision of biochemical data relating to fetal acid-base status at delivery influencing intrapartum care in subsequent cases. [source]

The effect of learning curve on the outcome of caesarean section

BJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 11 2006
WY Fok
Objective, To evaluate the operative outcomes when trainees first perform caesarean sections independently. Design, A retrospective study in a tertiary obstetric unit. Population, Five hundred caesarean sections, which represented the first 50 caesarean sections performed independently by each of ten trainees, were studied. Methods, The effect of learning curve on outcome was analysed. Main outcome measures, Total operative time, incision-to-delivery interval, operative blood loss, Apgar score, cord arterial pH, incidence of neonatal intensive care unit admission, postoperative complication rates and duration of hospitalisation. Results, The mean operative time for the first five cases by trainees was 52.2 ± 11.4 minutes. It progressively decreased and reached 39.6 ± 8.4 minutes for the 46th to 50th cases. The operative time was significantly longer in the first 15 caesarean sections (P < 0.05). Moreover, the incision-to-delivery interval was also longer during the first five cases (P= 0.02). Besides the time of the operation, the trend for operative blood loss stabilised after the first ten caesarean sections (P < 0.05). Otherwise, there were no significant differences among other outcome variables. Conclusion, This study shows that trainees need to perform 10,15 caesarean sections before their skills become more proficient. Senior obstetricians may need to provide guidance to the trainees during their first independent 15 caesarean sections. [source]

Deterioration in cord blood gas status during the second stage of labour is more rapid in the second twin than in the first twin

BJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 6 2004
Tak-Yeung Leung
Objective To compare in twin pregnancy the rate of deterioration in umbilical blood gas status during the second stage of labour, and to investigate whether the duration of the first twin's delivery has any effect on the blood gas status of the second twin. Design A retrospective study. Setting Department of Obstetrics and Gynaecology in a university teaching hospital. Population Twin pregnancies with both of the twins delivered by normal cephalic vaginal mode, at or beyond 34 weeks of gestation, over a period of seven years. Twins with any maternal or fetal complications including discordant growth, intrauterine growth restriction, intrauterine death, fetal malformations, fetal distress, pre-eclampsia and diabetes were excluded. Methods The first twins' second stage was defined as from the start of maternal pushing to his/her delivery, while the second twins' second stage started after the delivery of the first twin and ended by his/her delivery. The total duration of the second stage was the sum of the above two intervals. The correlations between the first twins' umbilical cord blood gas parameters and the duration of their own second stage, the second twins' umbilical cord blood gas parameters and the duration of their own second stage, as well as that of the total second stage, were studied. Main outcome measures The changes of umbilical arterial pH of each twin with the duration of the corresponding second stage of labour, and the difference among them. Results A total of 51 cases were reviewed. The median gestation at delivery was 37 weeks. The median duration of first twins' second stage was 10 minutes (range 1,75) while that of the second twins' was 10 minutes (range 3,26). The first twins' second stage was inversely correlated with their arterial pH, venous pH and base excess [BE] (P < 0.01). Both the second twins' second stage and the total second stage were inversely correlated with both of their arterial and venous pH and BE (P < 0.01). However, further multiple regression analysis suggested that the correlation of the total second stage with the second twins' cord blood parameters could be solely explained by their own second stage. The rate of reduction in the second twins' arterial pH was 4.95 × 10,3 per minute, and was significantly faster than that of the first twins', which was 1.55 × 10,3 per minute (P < 0.05). Conclusions During normal vaginal delivery, the umbilical cord blood gas status of both the first and the second twins deteriorated with the duration of their corresponding second stages, but the effects are greater in the latter. Furthermore, the duration of the first twins' second stage does not affect the blood gas status of the second twins'. These observations support the postulation of a diminished uteroplacental exchange function after the delivery of the first twin. Close monitoring and expeditious delivery of the second twins are important. [source]

Fetal activin A: associations with labour, umbilical artery pH and neonatal outcome

BJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 4 2004
Stephen Tong
Objective To define the ontogeny of umbilical artery activin A at term and to evaluate activin A as a potential marker of perinatal hypoxia. Design A cohort study. Setting A university teaching hospital delivery suite. Population A convenience sample of 141 term pregnancies. Methods At delivery, umbilical artery and vein bloods were collected for blood gas measurements and subsequent measurement of activin A. Activin A levels were correlated with blood gas measurements and with labour and neonatal outcomes. Main outcome measures Umbilical arterial activin A and pH. Results The median (95% CI) umbilical arterial activin A level at delivery was 1.38 (1.34,1.70) ng/mL. Levels varied significantly across gestation (P= 0.03), increasing from 36 to 38 weeks, thereafter decreasing to a nadir at 41 weeks. In 60 matched samples, the median (95% CI) venous and arterial activin A levels were 0.89 (0.81,1.06) ng/mL and 1.38 (1.21,1.61) ng/mL, respectively (P < 0.0001). Mean umbilical arterial pH was 7.20 (7.06,7.38; 5,95th centiles) and was not significantly correlated with log10 activin A (r=, 0.01; P= 0.68). Compared with healthy controls, there was no difference in arterial activin A in neonates identified as having suffered significant intrapartum asphyxia (P= 0.96). Fetal activin A levels were significantly lower in cases delivered by emergency caesarean section for complications during the first stage of labour compared with cases delivered vaginally (P= 0.003). Conclusions Umbilical artery activin A does not appear to be a sensitive marker of fetal oxygenation or of risk of hypoxic,ischaemic encephalopathy. [source]