Samples For Blood Gas Analysis Research Articles

Mathematical Arterialization of Capillary Blood for Blood Gas Analysis in Critically Ill Patients

Background: In clinical practice, capillary blood taken from hyperemized earlobes (CBG_E) or fingertips (CBG_F) is frequently used as substitute for arterial blood (ABG) for blood gas analysis. While there is a close agreement between ABG and CBG_E/CBG_F regarding pH and pCO₂, pO₂ is often underestimated by CBG. Recently, a software tool (v-TAC^®; Roche Diagnostics, Risch-Rotkreuz, Switzerland) has been developed to calculate ABG values based on a peripheral venous blood gas analysis supplemented with peripheral oxygen saturation. Objective: Here we investigate whether v-TAC can also be used to calculate ABG values from capillary blood samples. Methods: Patients (n = 85) with an indwelling arterial line were included in the study. A reference ABG sample (ABG₁) was obtained, followed by CBG_E, CBG_F, and finally a second ABG (ABG₂). Results of CBG_E/CBG_F before and after mathematical arterialization by v-TAC (aCBG_E/aCBG_F) were compared to ABG₁. Results: After mathematical arterialization by v-TAC, the mean bias in pO₂ between ABG₁ and CBG_E went down from 5.24 mm Hg (95% limit of agreement [95% LoA]: −14.19 to 24.67) to 0.18 mm Hg (95% LoA: −11.84 to 12.20) and was in a similar range as the mean bias between ABG₁ and ABG₂ (0.39 mm Hg [95% LoA: −13.46 to 14.24]). Differences in pH and pCO₂ between arterial and capillary samples were small before and after mathematical arterialization. Very similar results were obtained when using fingertip instead of earlobe capillary blood. Conclusion: In summary, v-TAC can be used for mathematical arterialization of capillary blood samples for blood gas analysis resulting in increased diagnostic accuracy for pO₂.

Dynamic changes in arterial blood gas during cardiopulmonary resuscitation in out-of-hospital cardiac arrest

We aimed to investigate the prognostic value of dynamic changes in arterial blood gas analysis (ABGA) measured after the start of cardiopulmonary resuscitation (CPR) for return of spontaneous circulation (ROSC) in patients with out-of-hospital cardiac arrest (OHCA). This prospective observational study was conducted at the emergency department of a university hospital from February 2018 to February 2020. All blood samples for gas analysis were collected from a radial or femoral arterial line, which was inserted during CPR. Changes in ABGA parameters were expressed as delta (Δ), defined as the values of the second ABGA minus the values of the initial ABGA. The primary outcome was sustained ROSC. Out of the 80 patients included in the analysis, 13 achieved sustained ROSC after in-hospital resuscitation. Multivariable logistic analysis revealed that ΔpaO2 (odds ratio [OR] = 1.023; 95% confidence interval [CI] = 1.004–1.043, p = 0.020) along with prehospital shockable rhythm (OR = 84.680; 95% CI = 2.561–2799.939, p = 0.013) and total resuscitation duration (OR = 0.881; 95% CI = 0.805–0.964, p = 0.006) were significant predictors for sustained ROSC. Our study suggests a possible association between ΔpaO2 in ABGA during CPR and an increased rate of sustained ROSC in the late phase of OHCA.

Sudden Rupture of Small Pseudoaneurysm of the Radial Artery in a Patient with COVID-19 Pneumonia

We report the case of sudden rupture of a radial artery small Pseudoaneurysm (PSA) occurring in a 63-years-old patient who had been hospitalized for COVID-19 pneumonia. A 63-years-old man was admitted to our hospital for SARS-CoV-2 infection causing progressive respiratory failure that required non-invasive mechanical ventilation. A 4 French catheter was placed in his right radial artery at the level of the wrist for repetitive arterial blood sampling for gas analysis. During the hospitalization, the patient recovered from the respiratory distress and the arterial line was removed, but he developed a focal ectasia of the radial artery (6 mm), which was treated with compression and antibiotics. However, after 2 days, a sudden hemorrhage from the wrist occurred, requiring emergent surgery. Intraoperatively, the radial artery was completely disrupted without any possibility of reconstruction due to the malacic wall. The artery was then ligated, and the postoperative course was uneventful. Small radial PSA following arterial catheterization may be complicated by sudden rupture in patients with COVID-19. Vascular surgeons should therefore be aware of such complication to prevent potentially serious consequences.

Elevated admission lactate levels in the emergency department are associated with increased 30-day mortality in non-trauma critically ill patients

BackgroundElevated blood lactate levels were reported as useful predictors of clinical outcome and mortality in critically ill patients. To identify higher-risk patients, this investigation evaluated the relationship between patient mortality and admission lactate levels during the management of non-trauma critically ill patients in the emergency department (ED).MethodsIn this prospective, single centre observational study in a German university ED, all adult patients who were admitted to the ED resuscitation room were evaluated between September 1, 2014 and August 31, 2015. Blood samples for blood gas analysis, including lactate levels, were obtained immediately at admission. Study endpoint was 30-day mortality.ResultsDuring the study period, 532 patients were admitted to the resuscitation room of the ED. The data of 523 patients (98.3%) were available. The overall 30-day mortality was 34.2%. Patients presenting to the resuscitation room with admission lactate levels < 2.0 mmol/l had a 30-day mortality of 22.7%, while admission lactate levels above 8.0 mmol/l were associated with higher mortality (8.0–9.9 mmol/l: OR: 2.83, 95%CI: 1.13–7.11, p = 0.03, and ≥ 10 mmol/l: OR: 7.56, 95%CI: 4.18–13.77, p < 0.001).ConclusionHigh lactate levels at admission are associated with an increased 24-h and 30-day mortality. These measurements may be used not only to predict mortality, but to help identify patients at risk for becoming critically ill. The breakpoint for mortality may be an ALL ≥8.0 mmol/l.

Blood sampled from existing peripheral IV cannulae yields results equivalent to venepuncture: a systematic review.

SummaryObjectivesTo establish whether blood samples taken from used peripheral intravenous cannulae are clinically interchangeable with venepuncture.DesignSystematic review. PubMed, Web of Science and Embase were searched for relevant trials.SettingTrials which compared blood samples from used peripheral intravenous cannulae to venepuncture and provided limits of agreement or data which allowed calculation of limits of agreement.ParticipantsSeven trials with 746 participants. Blood tests included 13 commonly ordered biochemistry, haematology and blood gas measurements.Main outcome measures95% limits of agreement. Data were pooled using inverse variance weighting and compared to a clinically acceptable range estimated by expert opinion from previous trials.ResultsLimits of agreement for blood samples from used peripheral intravenous cannulae were within the clinically acceptable range for sodium, chloride, urea, creatinine and haematology samples. Limits of agreement for potassium were ±0.47 mmol/L which exceeded the clinically acceptable range. Peripheral intravenous cannula samples for blood gas analysis gave limits of agreement which far exceeded the clinically acceptable range.ConclusionsBlood sampling from used peripheral intravenous cannulae is a reasonable clinical practice for haematology and biochemistry samples. Potassium samples from used peripheral intravenous cannulae can be used in situations where error up to ±0.47 mmol/L is acceptable. Peripheral intravenous cannula samples should not be used for blood gas analysis.

Ex Vivo Normothermic Perfusion, a Novel Method to Assess Pancreases after Preservation

Julien Branchereau1,2* and Etohan Ogbemudia1*, Kaithlyn Rozenberg1, Fungai Dengu1, Gabriella Hakim1, Flavia Neri1, Georg Ebeling1, Letizia Lo Faro1, James Hunter1, Rutger Ploeg1* and Peter Friend1*&#x0D; * "Authors contributed equally to this work"&#x0D; 1-Nuffield Department of Surgical Sciences - University of Oxford&#x0D; 2-Nantes Hospital University - France&#x0D; Introduction&#x0D; Static cold storage (SCS) of pancreases remains the current standard method for preservation prior to transplantation. Pulsatile hypothermic machine perfusion (HMP) is an emerging method that could potentially improve the preservation of pancreases to enhance graft function. This is based on personal extensive experience with HMP of pancreases in human, porcine allotransplantation and large non-human primate models. All models consistently showed preservation of pancreatic parenchyma on histological assessment for up to 24hours. To provide reassurance of organ viability prior to transplantation further investigations are necessary. We propose that normothermic perfusion (NMP) of pancreases after cold preservation allows necessary functional and physiological assessments.&#x0D; Method&#x0D; Porcine pancreases (3) were retrieved from the slaughterhouse after 30 minutes of warm ischaemia and were flushed. After 3 hours of cold ischaemia two pancreases were perfused by HMP (Wave machine; Waters Medical Systems) for 6 hours followed by 1 hour of NMP. One pancreas after 3 hours of CIT was placed on NMP for 2.5hours, this was the first pancreas NMP to assess feasibility of this technique.NMP was achieved by modification of the kidney assist device. Oxygenation was with 21% oxygen. The pancreases were cannulat ed via the aorta with free drainage of perfusate from the portal vein. NMP parameters for all pancreases were a pressure of 40mmHg and temperature of 37C. Perfusate was composed of red blood cells, plasma to provide a haematocrit of 25%, with additives of co-amoxiclav and 25,000IU of heparin. During the perfusions we collected serial perfusate samples for blood gas analysis and for insulin enzyme-linked immunosorbent assay (ELISA).&#x0D; Results&#x0D; The macroscopic appearance of the pancreases and the attached duodenum at the end of NMP appeared viable. Average resistance index during NMP was 0.62 ru (range 0.30 to 0.90 ru). Average flow rate was 77mls/min (range 53 to 100 mls/min). Throughout, the duration of NMP in the two pancreases perfused for one-hour lactate remain stable with no increase from baseline. In the one pancreas perfused for 2.5hours lactate was also stable in the first hour then increased by 50% during the last 1.5hours of perfusion. ELISA confirmed the presence of insulin in the perfusate for all three perfusions.&#x0D; Conclusion&#x0D; Normothermic perfusion is a feasible method to allow physiological and functional assessment of pancreases after cold preservation techniques encouraging us to further develop this model.&#x0D;

Kinetics of acid-base parameters in conventional hemodialysis.

Details about the acid-base changes in hemodialysis are scarce in the literature but are potentially relevant to adequate management of patients. We addressed the acid-base kinetics during hemodialysis and throughout the interdialytic period in a cross-sectional study of adults undergoing conventional hemodialysis. Samples for blood gas analysis were obtained from the arterial limb of the arteriovenous fistula before the first session of the week (HD1), immediately at the end of HD1, and on sequential collections at 15, 30, 45, 60, and 120 min post-HD1. Additional blood samples were collected after ∼20 h following the end of the first dialysis and immediately prior to the initiation of the second dialysis of the week. Thirty adult patients were analyzed (55±15 years, 50% men, 23% diabetic; dialysis vintage 69±53 months). Mean serum bicarbonate levels increased at the end of HD1 (22.3±2.7 mEq/L vs 17.5±2.3 mEq/L, P<0.001) and remained stable until 20 h after the end of the session. The mean values of pCO2 before HD1 were below reference and at 60 and 120 min post-HD1 were significantly lower than at the start (31.3±2.7 mmHg and 30.9±3.7 mmHg vs 34.3±4.1 mmHg, P=0.041 and P=0.010, respectively). The only point of collection in which mean values of pCO2 were above 35 mmHg was 20 h post-dialysis. Serum bicarbonate levels remained stable for at least 20 h after the dialysis sessions, a finding that may have therapeutic implications. During dialysis, the respiratory response for correction of metabolic acidosis (i.e., pCO2 elevation) was impaired.

Acid-base balance in sheep with experimentally induced acute ruminal lactic acidosis

ABSTRACT This study aimed to investigate the changes in the acid-base balance of sheep with experimentally induced acute ruminal lactic acidosis (ARA). Ten ewes orally received 15 grams of sucrose per kilogram of body mass. Arterial blood samples for blood gas analysis were obtained at the following intervals: before the induction of ARA (control), and 2, 4, 6, 8, 10, 12, 16, 20, 24, 28, 32, 36, 48, 72, 96, 120 and 144 hours after sucrose administration. Urine samples for pH measurement were obtained at the following times: -15 days, -7 days, and immediately before sucrose administration, then at 24, 48, 72, 96, 120 and 144 hours. Thereafter, both blood and urine samples were obtained on the 2nd, 3rd, and 4th following weeks. From 4 hours after the induction, elevation of the pH, bicarbonate and base excess on the arterial blood was observed. After 12 hours, the animals showed a decrease of these parameters, as well as urine acidification, which are symptomatic of metabolic acidosis. Within 28 hours, all parameters were normalized except the base excess, which only returned to normal after 72 hours. Despite the occurrence of acidemia, there was no need for medication and no animals died.

Comparison of an automatic analysis and a manual analysis of conjunctival microcirculation in a sheep model of haemorrhagic shock.

BackgroundLife-threatening diseases of critically ill patients are known to derange microcirculation. Automatic analysis of microcirculation would provide a bedside diagnostic tool for microcirculatory disorders and allow immediate therapeutic decisions based upon microcirculation analysis.MethodsAfter induction of general anaesthesia and instrumentation for haemodynamic monitoring, haemorrhagic shock was induced in ten female sheep by stepwise blood withdrawal of 3 × 10 mL per kilogram body weight. Before and after the induction of haemorrhagic shock, haemodynamic variables, samples for blood gas analysis, and videos of conjunctival microcirculation were obtained by incident dark field illumination microscopy. Microcirculatory videos were analysed (1) manually with AVA software version 3.2 by an experienced user and (2) automatically by AVA software version 4.2 for total vessel density (TVD), perfused vessel density (PVD) and proportion of perfused vessels (PPV). Correlation between the two analysis methods was examined by intraclass correlation coefficient and Bland-Altman analysis.ResultsThe induction of haemorrhagic shock decreased the mean arterial pressure (from 87 ± 11 to 40 ± 7 mmHg; p < 0.001); stroke volume index (from 38 ± 14 to 20 ± 5 ml·m−2; p = 0.001) and cardiac index (from 2.9 ± 0.9 to 1.8 ± 0.5 L·min−1·m−2; p < 0.001) and increased the heart rate (from 72 ± 9 to 87 ± 11 bpm; p < 0.001) and lactate concentration (from 0.9 ± 0.3 to 2.0 ± 0.6 mmol·L−1; p = 0.001). Manual analysis showed no change in TVD (17.8 ± 4.2 to 17.8 ± 3.8 mm*mm−2; p = 0.993), whereas PVD (from 15.6 ± 4.6 to 11.5 ± 6.5 mm*mm−2; p = 0.041) and PPV (from 85.9 ± 11.8 to 62.7 ± 29.6%; p = 0.017) decreased significantly. Automatic analysis was not able to identify these changes. Correlation analysis showed a poor correlation between the analysis methods and a wide spread of values in Bland-Altman analysis.ConclusionsAs characteristic changes in microcirculation during ovine haemorrhagic shock were not detected by automatic analysis and correlation between automatic and manual analyses (current gold standard) was poor, the use of the investigated software for automatic analysis of microcirculation cannot be recommended in its current version at least in the investigated model. Further improvements in automatic vessel detection are needed before its routine use.Electronic supplementary materialThe online version of this article (doi:10.1186/s40635-016-0110-5) contains supplementary material, which is available to authorized users.

Efficacy of a portable oxygen concentrator with pulsed delivery for treatment of hypoxemia during equine field anesthesia

ObjectiveHypoxemia is common during equine field anesthesia. Our hypothesis was that oxygen therapy from a portable oxygen concentrator would increase PaO2 during field anesthesia compared with the breathing of ambient air. Study designProspective clinical study. AnimalsFifteen yearling (250 – 400 kg) horses during field castration. MethodsHorses were maintained in dorsal recumbency during anesthesia with an intravenous infusion of 2000 mg ketamine and 500 mg xylazine in 1 L of 5% guaifenesin. Arterial samples for blood gas analysis were collected immediately post-induction (PI), and at 15 and 30 minutes PI. The control group (n = 6) breathed ambient air. The treatment group (n = 9) were administered pulsed-flow oxygen (192 mL per bolus) by nasal insufflation during inspiration for 15 minutes PI, then breathed ambient air. The study was performed at 1300 m above sea level. One-way and two-way repeated-measures anova with post-hoc Bonferroni tests were used for within and between-group comparisons, respectively. Significance was set at p ≤ 0.05. ResultsMean ± SD PaO2 in controls at 0, 15 and 30 minutes PI were 46 ± 7 mmHg (6.1 ± 0.9 kPa), 42 ± 9 mmHg (5.6 ± 1.1 kPa), and 48 ± 7 mmHg (6.4 ± 0.1 kPa), respectively (p = 0.4). In treatment animals, oxygen administration significantly increased PaO2 at 15 minutes PI to 60 ± 13 mmHg (8.0 ± 1.7 kPa), compared with baseline values of 46 ± 8 mmHg (6.1 ± 1 kPa) (p = 0.007), and 30 minute PI values of 48 ± 7 mmHg (6.5 ± 0.9 kPa) (p = 0.003). ConclusionsThese data show that a pulsed-flow delivery of oxygen can increase PaO2 in dorsally recumbent horses during field anesthesia with ketamine-xylazine-guaifenesin. Clinical relevanceThe portable oxygen concentrator may help combat hypoxemia during field anesthesia in horses.

Effect of Intravenous Administration of Tramadol on the Minimum Alveolar Concentration of Isoflurane in Dogs

This study was aimed to evaluate the effects of tramadol hydrochloride on the minimum alveolar concentration of isoflurane (MAC ISO ) in dogs. Six healthy, female German shepherd dogs (aged 1-2 years) were used in this study. Anesthesia was induced by mask induction and maintained with isoflurane in oxygen. Mechanical ventilation maintained the end-tidal CO₂ partial pressure (P ET CO₂) from 35 to 45 mmHg throughout the study. A baseline MAC ISO (MAC ISO B) was determined starting 45 minutes after induction of anesthesia by clamping a pedal digit until gross purposeful movement was detected. After MAC ISO B determination, dogs received a tramadol loading dose of 3 mg/kg followed by a continuous rate infusion (CRI) of 2.6 mg/kg/h. The determination of MAC ISO after administration of tramadol (MAC ISO T) began 20 min after the start of the CRI. Arterial blood pressure and heart rate were recorded continuously and arterial blood samples for blood gas analysis were collected at the end of the equilibration period. Mean ± SD values for the MAC ISO B and MAC ISO T were 1.33 ± 0.04% and 1.23 ± 0.04%, respectively. The MAC ISO B decreased significantly by 7.5 ± 0.2% (P ISO without depression of cardiorespiratory function. Thus, the use of tramadol on inhalation anesthesia with isoflurane in dogs can improve the stability of anesthesia and the quality of recovery.

Effects of delayed compared with early umbilical cord clamping on maternal postpartum hemorrhage and cord blood gas sampling: a randomized trial

To investigate the effect of delayed cord clamping (DCC) compared with early cord clamping (ECC) on maternal postpartum hemorrhage (PPH) and umbilical cord blood gas sampling. Secondary analysis of a parallel-group, single-center, randomized controlled trial. Swedish county hospital. 382 term deliveries after a low-risk pregnancy. Deliveries were randomized to DCC (≥180 seconds, n = 193) or ECC (≤10 seconds, n = 189). Maternal blood loss was estimated by the midwife. Samples for blood gas analysis were taken from one umbilical artery and the umbilical vein, from the pulsating unclamped cord in the DCC group and from the double-clamped cord in the ECC group. Samples were classified as valid when the arterial-venous difference was -0.02 or less for pH and 0.5 kPa or more for pCO2 . Main outcome measures. PPH and proportion of valid blood gas samples. The differences between the DCC and ECC groups with regard to PPH (1.2%, p = 0.8) and severe PPH (-2.7%, p = 0.3) were small and non-significant. The proportion of valid blood gas samples was similar between the DCC (67%, n = 130) and ECC (74%, n = 139) groups, with 6% (95% confidence interval: -4%-16%, p = 0.2) fewer valid samples after DCC. Delayed cord clamping, compared with early, did not have a significant effect on maternal postpartum hemorrhage or on the proportion of valid blood gas samples. We conclude that delayed cord clamping is a feasible method from an obstetric perspective.

Cardiopulmonary and sedative effects of the peripheral α2-adrenoceptor antagonist MK 0467 administered intravenously or intramuscularly concurrently with medetomidine in dogs

To evaluate the cardiopulmonary and sedative effects of the peripheral α(2)-adrenoceptor antagonist MK 0467 when administered IM or IV concurrently with medetomidine in dogs. 8 adult dogs. Dogs received 20 μg of medetomidine/kg, IM, alone or concurrently with MK 0467 (0.4 mg/kg, IM), and 10 μg of medetomidine/kg, IV, alone or concurrently with MK 0467 (0.2 mg/kg, IV), in a randomized crossover study. Sedation characteristics were scored and hemodynamic measurements and arterial and mixed-venous blood samples for blood gas analysis were obtained before (time 0; baseline) and for 90 minutes after treatment. Heart rate (HR), mixed-venous partial pressure of oxygen (Pvo(2)), and cardiac index (CI) were significantly lower and mean arterial blood pressure (MAP), systemic vascular resistance (SVR), and oxygen extraction ratio (ER) were significantly higher after administration of medetomidine IM or IV, compared with baseline values. Administration of medetomidine and MK 0467 IM caused a significantly higher heart rate, CI, and Pvo(2) and significantly lower MAP, SVR, and ER for 60 to 90 minutes than did IM administration of medetomidine alone. Administration of medetomidine and MK 0467 IV caused a significantly higher CI and Pvo(2) and significantly lower MAP, SVR, and ER for 45 to 90 minutes than did IV administration of medetomidine alone. There was no significant difference in sedation scores among treatments. In dogs, MK 0467 administered concurrently with medetomidine IV or IM reduced the cardiovascular effects of medetomidine but had no detectable effect on sedation scores.

Copeptin Response to Clinical Maximal Exercise Tests

Copeptin (the glycosylated 39–amino acid C-terminal fragment of the arginine vasopressin (AVP)1 precursor peptide), when measured with a novel assay (1), has emerged as a promising marker for the early diagnosis of acute myocardial infarction (MI)(2) and a powerful prognostic marker in a variety of settings. The underlying mechanism is thought to be the role of copeptin as a measure of a high individual stress level(3). Interestingly, exercise seems to elicit a significant increase in circulating copeptin concentrations within minutes(4). The aim of our study was to assess the copeptin response to exercise and its determinants. We studied 414 consecutive patients undergoing myocardial perfusion scintigraphy (n = 253) or cardiopulmonary exercise testing (CPET) (n = 161) with upright symptom-limited cycle ergometer tests (increments of 10–25 W/min). In the CPET cohort, arterial samples for blood gas analysis were obtained at rest and peak exercise and were analyzed immediately. In all patients, venous blood was drawn immediately from a catheter in an antecubital vein with the patient in the seated position (rest) before the test and immediately after test termination (peak exercise). These samples were collected in EDTA-containing tubes, placed on ice, and centrifuged at 3000 g . Plasma samples were stored at …

Effects of a peripheral α2 adrenergic-receptor antagonist on the hemodynamic changes induced by medetomidine administration in conscious dogs

To evaluate the effects of administration of a peripheral alpha(2)-adrenergic receptor antagonist (L-659,066), with and without concurrent administration of glycopyrrolate, on cardiopulmonary effects of medetomidine administration in dogs. 6 healthy adult dogs. Dogs received saline (0.9% NaCl) solution (saline group), L-659,066 (group L), or L-659,066 with glycopyrrolate (group LG). These pretreatments were followed 10 minutes later by administration of medetomidine in a randomized crossover study. Hemodynamic measurements and arterial and mixed-venous blood samples for blood gas analysis were obtained prior to pretreatment, 5 minutes after pretreatment, and after medetomidine administration at intervals up to 60 minutes. After pretreatment in the L and LG groups, heart rate, cardiac index, and partial pressure of oxygen in mixed-venous blood (PvO2) values were higher than those in the saline group. After medetomidine administration, heart rate, cardiac index, and PvO2 were higher and systemic vascular resistance, mean arterial blood pressure, and central venous pressure were lower in the L and LG groups than in the saline group. When the L and LG groups were compared, heart rate was greater at 5 minutes after medetomidine administration, mean arterial blood pressure was greater at 5 and 15 minutes after medetomidine administration, and central venous pressure was lower during the 60-minute period after medetomidine administration in the LG group. Administration of L-659,066 prior to administration of medetomidine reduced medetomidine-induced cardiovascular changes in healthy dogs. No advantage was detected with concurrent administration of L-659,066 and glycopyrrolate.

Urinary excretion of both D‐ and L‐lactate using a calf‐infusion model

D‐lactic acidosis is recognized as a complication of gastrointestinal diseases in humans and ruminants. Absorbed D‐lactate can be excreted via the kidney; however, competition between D‐ and L‐lactate in the renal mechanisms may effect its elimination. The objective of this study was to measure D‐ and L‐lactate clearance in a calf infusion model. Five calves (age 14–31 days, weight 59 ± 8 kg) were infused with DL‐ and L‐lactic acid (300 mmol/L, 2 mL/kg/h for 8 hours) in a randomized cross‐over design. Calves were fitted with intravenous catheters for infusion and blood collection, and with suprapubic bladder catheters for urine collection. Samples for blood gas analysis, serum and urine D‐ and L‐lactate concentration, urine volume and serum and urine creatinine were collected every 2 hours for 24 hours. D‐ and L‐lactate clearances were calculated for each 2 hour interval and compared to creatinine clearance. With infusion of DL‐lactate, average serum D‐lactate concentration at steady state was 2.9 ± 1.6 mmol/L (range 1.8–5.7 mmol/L), and average urine D‐lactate concentration was 4.0 ± 1.7 mmol/L. Average D‐lactate clearance during steady state was 7.4 ± 3.4 mL/min. Percent excretion of infused D‐lactate increased during the 8 hour infusion, with minimum and maximum excretion averaging 0.6 ± 0.1% and 10.4 ± 4.4%. L‐lactate clearance could not be calculated, likely due to rapid metabolism of infused L‐lactate. Therefore, L‐lactate elimination is more efficient than D‐lactate since it can both be metabolized and excreted from the body. (Supported by NSERC Canada)

Finger Necrosis Following Percutaneous Radial Artery Cannulation - A case report -

Anesthegiologists commonly use arterial cannulation for both close blood pressure monitoring and repeated blood sampling for gas analysis. Radial artery cannulation is generally thought of as a safe and uncomplicated procedure, however, some possible complications have been reported. These include bleeding, hematoma, infection, pseudoaneurysm and thromboembolism, which do not usually result in any serious clinical problems. Although it is not common, thromboembolism could be serious because it can lead to digital ischemia and necrosis. We report here a case of finger necrosis following radial artery cannulation in a patient who underwent radical hysterectomy under general anesthesia.

Agreement of simplified Fencl-Stewart with Figge-Stewart method in diagnosing metabolic acidosis in critically ill children

Background The traditional Henderson-Hasselbalch approach hasproven to be imprecise in critically ill patients. Stewart’s approachcan detect metabolic acidosis missed by traditional approach,including acidosis caused by increased unmeasured agreement(UA). The complexity of Stewart’s method leads to developmentof simpler modifications, simplified Fencl-Stewart and Figge-Stewart method. Agreement between both modifications isunknown.Objective This study aimed to measure the agreement of simplifiedFencl-Stewart with Figge-Stewart method in diagnosing metabolicacidosis in critically ill children.Methods The was performed in Hasan Sadikin General Hospital,Bandung from July to August 2006, involving &lt;14 year-old criticallyill children. Blood samples for gas analysis, sodium, potassium,chloride and albumin measurement were taken simultaneously. Testresult was analyzed with simplified Fencl-Stewart and Figge-Stewartmethod and recorded with Excell spreadsheet. PASS was used forinterim analysis and DAG_Stat for raw agreement indices andKappa calculations.Results Forty-five (31 males, 14 females) children were enrolled.Acid base disturbances based on Stewart’s method were identifiedin 10 subjects with normal base excess and nine with normalbicarbonate. Significant increase of UA was detected in 11 of 45subjects with simplified Fencl-Stewart method, compared to thatof 12 subjects with Figge-Stewart method. Raw agreement indicesshowed 95.65% and 98.51% agreement for positive and negativeresult, Kappa was 0.94 (P=0.0000).Conclusions Excellent agreement is shown between simplifiedFencl-Stewart and Figge-Stewart method in diagnosing metabolicacidosis in critically ill children. Increased UA can be assessedwith both methods.

Adjusting Oxygen Fraction to Avoid Hyperoxemia during Cardiopulmonary Bypass

Although an adverse influence of hyperoxemia during cardiopulmonary bypass is well documented, there is a wide range of oxygen settings during cardiopulmonary bypass, based mostly on trial and error. The aim of this study was to determine the optimal inspired oxygen fraction during cardiopulmonary bypass. Ninety patients undergoing isolated coronary artery bypass operations were randomly allocated to one of 3 groups of 30 each. In group 1, cardiopulmonary bypass was started with an inspired oxygen fraction of 0.40, increased to 0.60 during rewarming. These settings were 0.40 and 0.50 in group 2, and 0.35 and 0.45 in group 3. Samples for blood gas analysis were collected at defined time periods during the operation. PaO(2) was significantly higher in groups 1 and 2 compared to group 3. All patients in group 1 and 88% of patients in group 2 suffered at least one episode of hyperoxemia during cardiopulmonary bypass, compared to 30% of patients in group 3. The differences were significant, and we concluded that to avoid hyperoxemia, inspired oxygen fraction should be kept at 0.35 during cardiopulmonary bypass and increased to 0.45 during rewarming.

High positive end-expiratory pressure levels promote bacterial translocation in experimental pneumonia

A previous study in piglets with experimental pneumonia showed that reducing atelectasis by means of open lung ventilation attenuated bacterial translocation compared to conventional ventilation settings. This study examined the effect of open lung ventilation with higher than necessary positive end-expiratory pressures (PEEP) on bacterial translocation. Prospective animal study in a university-affiliated research laboratory. Thirty piglets. Animals were surfactant-depleted by whole-lung lavage and infected with group B streptococci. Thereafter the animals were ventilated for 5 h according to either a conventional ventilation strategy, open lung strategy, or open lung/high-PEEP strategy. Blood samples for blood gas analysis and blood bacterial counts were taken every hour. After 5 h of ventilation surviving animals were killed, and lung colony forming units and lung mechanics parameters were determined. All animals in both open lung groups survived but only 30% of those in the conventional ventilation group. Open lung ventilation resulted in significantly less bacterial translocation than either conventional or high-PEEP ventilation. Lung function in the conventional ventilated group was significantly less than in the two open lung groups. The lowest level of bacterial translocation was observed during optimal ventilation (open lung) which was achieved by using individually tailored settings. Deviation to either side can be harmful, as shown by the increased bacterial translocation during conventional and high-PEEP ventilation.