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Arterial Blood Gases (arterial + blood_gase)
Selected AbstractsArterial blood gases in extraperitoneal laparoscopic urethrocystopexyINTERNATIONAL JOURNAL OF UROLOGY, Issue 8 2002Hasan Kocoglu Abstract Background: The aim of this study was to investigate the effects of extraperitoneal laparoscopy and carbon dioxide insufflation on hemodynamic parameters, arterial blood gases and complications in urethrocystopexy operations. Methods: Twenty-five female patients who underwent extraperitoneal laparoscopic mesh urethrocystopexy operation for the correction of urinary incontinence were allocated to the study. Hemodynamic parameters were noted and blood gas analyzes were performed before the induction of anesthesia, 10 min after induction, 5 and 10 min after the beginning of carbon dioxide insufflation, at the end of carbon dioxide insufflation and 30 min after exsufflation. Results: There was no significant change in mean arterial pressure, peripheral oxygen saturation, arterial carbon dioxide pressure, and arterial oxygen saturation compared to preinsufflation and preinduction values. End-tidal carbon dioxide pressure did not increase above 45 mm/Hg during carbon dioxide insufflation. Arterial oxygen saturation and partial oxygen pressure did not decrease. Subcutaneous emphysema, pneumothorax, pneumomediastinum and pleural effusion were not noted in any patient. Conclusion: We conclude that, extraperitoneal laparoscopic urethrocystopexy is not associated with hemodynamic and respiratory impairment. [source] Arterial oxygen tension increase 2,3 h after hyperbaric oxygen therapy: a prospective observational studyACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2007B. Ratzenhofer-Komenda Background:, Inhalation of hyperbaric oxygen (HBO) has been reported to decrease arterial oxygen tension (PaO2) in the early period after exposure. The current investigation aimed at evaluating whether and to what extent arterial blood gases were affected in mechanically ventilated intensive care patients within 6 h after HBO treatment. Methods:, Arterial blood gases were measured in 11 ventilated subjects [nine males, two females, synchronized intermittent mandatory ventilation (SIMV) mode] undergoing HBO therapy for necrotizing soft tissue infection (seven patients), burn injury (two patients), crush injury (one patient) and major abdominal surgery (one patient). Blood gases were obtained with the patients in the supine position under continuous analgesia and sedation before the hyperbaric session (baseline), during isopression, after decompression, after each transport, and 1, 2, 3 and 6 h after exposure. Heart rates and blood pressures were recorded. Intensive care unit (ICU) ventilator settings remained unchanged. Transport and chamber ventilator settings were adjusted to baseline with maintenance of tidal volumes and positive end-expiratory pressure (PEEP) levels. The hyperbaric protocol consisted of 222.9 kPa (2.2 absolute atmospheres) and a 50-min isopression phase. The paired Wilcoxon's test was used. Results:, Major findings (median values, 25%/75% quantiles) as per cent change of baseline: PaO2 values decreased by 19.7% (7.0/31.7, P < 0.01) after 1 h and were elevated over baseline by 9.3% (1.5/13.7, P < 0.05) after 3 h. SaO2, alveolar-arterial oxygen tension difference and PaO2/FiO2 ratio behaved concomitantly. Acid-base status and carbon dioxide tension were unaffected. Conclusion:, Arterial oxygen tension declines transiently after HBO and subsequently improves over baseline in intensive care patients on volume-controlled mechanical ventilation. The effectiveness of other ventilation modes or a standardized recruitment manoeuvre has yet to be evaluated. [source] Long-term effects of hypothermia on neuronal cell death and the concentration of apoptotic proteins after incomplete cerebral ischemia and reperfusion in ratsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2005E. Eberspächer Background:, The present study investigates the long-term effects of postischemic hypothermia on neuronal cell damage and concentration changes of apoptotic proteins after cerebral ischemia. Methods: Sixty-four Sprague-Dawley rats were anesthetized, intubated and ventilated with 2.0 Vol% isoflurane and 70% N2O/O2. After preparation the animals were randomly assigned to the following groups: group 1 (n = 32, fentanyl-N2O/normothermia 37.5°C), and group 2 (n = 32, fentanyl-N2O/hypothermia 34.0°C. Ischemia (45 min) was induced by common carotid artery occlusion plus hemorrhagic hypotension (MAP = 40 mmHg). Arterial blood gases and pH were maintained constant. After 1, 3, 7, or 28 days (each n = 8) the brains were removed, frozen and cut. Neuronal damage was assessed by analyzing Bax, Bcl-2, p53, and Mdm-2 proteins, activated caspases-3-positive and eosinophilic cells. A third group (n = 8) of untreated animals served as naive controls. Results:, In hypothermic animals, Bax concentration was decreased by 50,70% over time compared to normothermia. On days 1 and 3, Bcl-2 was increased by 50% with hypothermia. The amount of activated caspase-3-positive cells in the ischemic hemisphere was 0.5% in the hypothermic and 1,2% in the normothermic animals. Of the hippocampal cells, 10,25% were eosinophilic in both groups over time. Conclusion:, The present data show that hypothermia prevents an ischemia-induced increase of the pro-apoptotic protein Bax for as long as 28 days and increases the concentration of the antiapoptotic protein Bcl-2 up to 3 days compared to normothermic animals. Therefore, after cerebral ischemia, hypothermia has the sustained neuroprotective potential to shift apoptosis-related proteins towards neuronal cell survival. [source] Effects of remifentanil/propofol in comparison with isoflurane on dynamic cerebrovascular autoregulation in humansACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2001K. Engelhard Background: This study investigates the effects of remifentanil and propofol in comparison to isoflurane on dynamic cerebrovascular autoregulation in humans. Methods: In 16 awake patients dynamic cerebrovascular autoregulation was measured using transcranial Doppler sonography (TCD). Thereafter patients were intubated, ventilated with O2/air (FiO2=0.33) and randomly assigned to one of the following anesthetic protocols: group 1 (n=8): 0.5 ,g · kg,1 · min,1 remifentanil combined with a propofol-target plasma concentration of 1.5 ,g · ml,1; group 2 (n=8): 1.8 % isoflurane (1.5 MAC). Following 20 min of equilibration the autoregulatory challenge was repeated. Arterial blood gases and body temperature were maintained constant over time. Statistics: Mann-Whitney U-test and Wilcoxon signed-rank test. Results: Dynamic autoregulation was intact in all patients prior to induction of anesthesia expressed by an autoregulatory index (ARI) of 5.4±1.21 (mean±SD, group 1) and 5.9±0.98 (mean±SD, group 2). With remifentanil/propofol anesthesia dynamic autoregulation was similar to the awake state (group 1: ARI=4.9±0.88). In contrast, autoregulatory response was delayed with 1.5 MAC isoflurane (group 2, ARI=2.1±0.92) (P<0.05). Conclusion: These data show that dynamic cerebrovascular autoregulation is maintained with remifentanil-based total intravenous anesthesia. This is consistent with the view that narcotics (and hypnotics) do not alter the physiologic cerebrovascular responses to changes in MAP. In contrast, 1.5 MAC isoflurane delays cerebrovascular autoregulation compared to the awake state. [source] PERIOPERATIVE HIGH-DOSE OXYGEN THERAPY IN VASCULAR SURGERYANZ JOURNAL OF SURGERY, Issue 6 2007Phillip J. Puckridge Background: Patients undergoing infrainguinal bypass surgery have reduced baseline tissue oxygen tension and high rates of wound infections. The hypoxaemia worsens during surgery, potentially reducing the ability to combat bacterial lodgement. We investigated whether high-dose perioperative oxygen administration to patients undergoing infrainguinal arterial surgery results in increased tissue oxygenation. Methods: Ten consecutive patients undergoing infrainguinal arterial surgery had transcutaneous partial pressure of oxygen (TcpO2) measured preoperatively, intraoperatively after arterial clamps applied, postoperatively and at discharge. Measurements were taken with inspired oxygen concentration (FiO2) of 30% then 80%. Arterial blood gases were measured at the same times. Results: Tissue oxygenation showed no difference intraoperatively while arterial clamps were in place, but significantly higher tissue oxygenation was seen with use of high-dose oxygen (FiO2 80%) postoperatively (P < 0.05). Carbon dioxide levels in tissue increased while arterial clamps were in place (P < 0.01) and pH fell intraoperatively and following reperfusion (P < 0.05). Conclusion: The administration of high-dose oxygen to vascular surgical patients undergoing lower-limb arterial surgery results in increased tissue oxygen concentrations when perfusion is not reduced by the presence of arterial clamps. These results suggest the administration of high-dose oxygen intraoperatively may be beneficial in reducing wound infections, but further research is required. [source] The case for venous rather than arterial blood gases in diabetic ketoacidosisEMERGENCY MEDICINE AUSTRALASIA, Issue 1 2006Anne-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] Comparison of cardiovascular function and quality of recovery in isoflurane-anaesthetised horses administered a constant rate infusion of lidocaine or lidocaine and medetomidine during elective surgeryEQUINE VETERINARY JOURNAL, Issue 3 2010A. VALVERDE Summary Reasons for performing study: The effects of lidocaine combined with medetomidine or lidocaine alone on cardiovascular function during anaesthesia and their effects on recovery have not been thoroughly investigated in isoflurane-anaesthetised horses. Objectives: To determine the effects of an intraoperative i.v. constant rate infusion of lidocaine combined with medetomidine (Group 1) or lidocaine (Group 2) alone on cardiovascular function and on the quality of recovery in 12 isoflurane-anaesthetised horses undergoing arthroscopy. Hypothesis: The combination would depress cardiovascular function but improve the quality of recovery when compared to lidocaine alone in isoflurane-anaesthetised horses. Methods: Lidocaine (2 mg/kg bwt i.v. bolus followed by 50 µg/kg bwt/min i.v.) or lidocaine (same dose) and medetomidine (5 µg/kg bwt/h i.v.) was started 30 min after induction of anaesthesia. Lidocaine administration was discontinued 30 min before the end of surgery in both groups, whereas medetomidine administration was continued until the end of surgery. Cardiovascular function and quality of recovery were assessed. Results: Horses in Group 1 had longer recoveries, which were of better quality due to better strength and overall attitude during the recovery phase than those in Group 2. Arterial blood pressure was significantly higher in Group 1 than in Group 2 and this effect was associated with medetomidine. No significant differences in cardiac output, arterial blood gases, electrolytes and acid-base status were detected between the 2 groups. Conclusions and potential relevance: The combination of an intraoperative constant rate infusion of lidocaine and medetomidine did not adversely affect cardiovascular function in isoflurane-anaesthetised horses and improved the quality of recovery when compared to an intraoperative infusion of lidocaine alone. [source] Dynamic pharyngeal collapse in racehorsesEQUINE VETERINARY JOURNAL, Issue S36 2006A. G. BOYLE Summary Reason for performing study: Dynamic pharyngeal collapse (PC) is a condition seen in racehorses that can be career-ending. Objectives: To characterise and grade PC and describe the effects of PC on athletic performance. Methods: Medical records were reviewed for 828 horses, of which 49 (6%) records were identified as horses with a primary diagnosis of PC. Tapes of video-endoscopy of the pharynx during exercise were reviewed. Each video recording was assigned a grade (0,4) reflecting the degree of PC and a classification for severity of upper airway obstruction. Earnings per race prior to diagnosis of PC were compared to earnings per race after diagnosis of PC for all horses, as well as performance index (PI). Available exercising arterial blood gases were reviewed for horses with PC. Results: There were 35 (80%) Thoroughbreds (TB), and 9 (20%) Standardbreds (STD). 32 (73%) had a history of making an upper respiratory noise. 4 (9%) grade 1 PC, 8 (18%) grade 2 PC, 26 (59%) grade 3 PC, and 6 (14%) grade 4 PC. Seven (16%) horses were classified as mild PC, 18 (41%) as low-moderate PC, 14 (32%) as high-moderate PC, and 5 (11%) as severe PC. Of 30 horses 11 had abnormally decreased PaO2 and 8 horses had abnormally elevated PaCO2. A significant decrease was found in earnings per race prediagnosis when compared to post diagnosis earnings per race in horses ?4 years of age (P = 0.003). A significant decrease was also observed for earnings per race prediagnosis when compared to post diagnosis earnings per race in horses with grade 3 PC (P = 0.03) No significant differences were observed in PI before or after diagnosis of PC. Conclusions: There was a trend for PC to be observed in more TB than STD, and more males than females compared to the general hospital population. Horses with PC significant had decreases in arterial oxygenation. Racing records after a diagnosis of PC in all horses ?4 years of age suggesting that older horses have a guarded prognosis for continued success. Potential relevance: This study provides a classification system for dynamic pharyngeal collapse and suggests that older racehorses (?4 years of age) diagnosed with PC and all horses with grade 3 PC have a poor prognosis for return to previous level of performance. [source] Effects of inhalation of albuterol sulphate, ipratroprium bromide and frusemide on breathing mechanics and gas exchange in healthy exercising horsesEQUINE VETERINARY JOURNAL, Issue 3 2001W. M. BAYLY Summary The possibility that pre-exercise inhalation of a bronchodilator by healthy horses could improve their mechanics of breathing and enhance performance was investigated. Ipratropium bromide (0.35 ,g/kg bwt; n = 7) was administered by nebulisation 30 min before exercise and frusemide (1 mg/kg bwt; n = 6) was given in the same manner 2 h before exercise. Albuterol sulphate (360 and 720 ,g; n = 7) were administered with a metered dose inhaler 2 h before exercise. Each drug was investigated independently of the others using cross-over protocols. Horses completed incremental exercise tests and oxygen consumption, carbon dioxide production, arterial blood gases, heart rate and measures of breathing mechanics including total pulmonary resistance (RL) and nasopharyngeal resistance (RU) were determined for each exercise intensity. The resistance of the lower airways was calculated subsequently from the difference between RL and RU. None of the drugs tested had an effect on any of the variables measured, possibly because maximal bronchodilation is stimulated in healthy horses by the normal sympathoadrenergic response to exercise. Therefore, the pre-exercise inhalation of a bronchodilator by a healthy horse is unlikely to improve performance capacity. [source] PRECLINICAL STUDY: Mechanisms of respiratory insufficiency induced by methadone overdose in ratsADDICTION BIOLOGY, Issue 1 2010Lucie Chevillard ABSTRACT Methadone may cause respiratory depression. We aimed to understand methadone-related effects on ventilation as well as each opioid-receptor (OR) role. We studied the respiratory effects of intraperitoneal methadone at 1.5, 5, and 15 mg/kg (corresponding to 80% of the lethal dose-50%) in rats using arterial blood gases and plethysmography. OR antagonists, including intravenous 10 mg/kg-naloxonazine at 5 minutes (mu-OR antagonist), subcutaneous 30 mg/kg-naloxonazine at 24 hours (mu1-OR antagonist), 3 mg/kg-naltrindole at 45 minutes (delta-OR antagonist) and 5 mg/kg-Nor-binaltorphimine at 6 hours (kappa-OR antagonist) were pre-administered. Plasma concentrations of methadone enantiomers were measured using high-performance liquid chromatography coupled to mass-spectrometry. Methadone dose-dependent inspiratory time (TI) increase tended to be linear. Respiratory depression was observed only at 15 mg/kg and characterized by an increase in expiratory time (TE) resulting in hypoxemia and respiratory acidosis. Intravenous naloxonazine completely reversed all methadone-related effects on ventilation, while subcutaneous naloxonazine reduced its effects on pH (P < 0.05), PaCO2 (P < 0.01) and TE (P < 0.001) but only partially on TI (P < 0.001). Naltrindole reduced methadone-related effects on TE (P < 0.001). Nor-binaltorphimine increased methadone-related effects on pH and PaO2 (P < 0.05) Respiratory effects as a function of plasma R -methadone concentrations showed a decrease in PaO2 (EC50: 1.14 µg/ml) at lower concentrations than those necessary for PaCO2 increase (EC50: 3.35 µg/ml). Similarly, increased TI (EC50: 0.501 µg/ml) was obtained at lower concentrations than those for TE (EC50: 4.83 µg/ml). Methadone-induced hypoxemia is caused by mu-ORs and modulated by kappa-ORs. Additionally, methadone-induced increase in TE is caused by mu1- and delta-opioid receptors while increase in TI is caused by mu-ORs. [source] Acute Hypervolaemia Improves Arterial Oxygen Pressure in Athletes with Exercise-Induced HypoxaemiaEXPERIMENTAL PHYSIOLOGY, Issue 4 2003Gerald S. Zavorsky The aim of this study was to determine the effect of acute plasma volume expansion on arterial blood-gas status during 6.5 min strenuous cycling exercise comparing six athletes with and six athletes without exercise-induced arterial hypoxaemia (EIAH). We hypothesized that plasma volume expansion could improve arterial oxygen pressure in a homogeneous sample of athletes - those with EIAH. In this paper we have extended the analysis and results of our recently published surprising findings that lengthening cardiopulmonary transit time did not improve arterial blood-gas status in a heterogeneous sample of endurance cyclists. One 500 ml bag of 10% Pentastarch (infusion condition) or 60 ml 0.9% saline (placebo) was infused prior to exercise in a randomized, double-blind fashion on two different days. Power output, cardiac output, oxygen consumption and arterial blood gases were measured during strenuous exercise. Cardiac output and oxygen consumption were not affected by acute hypervolaemia. There were group × condition interaction effects for arterial oxygen pressure and alveolar-arterial oxygen pressure difference, suggesting that those with hypoxaemia experienced improved arterial oxygen pressure (+4 mmHg) and lower alveolar-arterial oxygen pressure difference (-2 mmHg) with infusion. In conclusion, acute hypervolaemia improves blood-gas status in athletes with EIAH. The impairment of gas exchange occurs within the first minute of exercise, and is not impaired further throughout the remaining duration of exercise. This suggests that arterial oxygen pressure is only minimally mediated by cardiac output. [source] Arterial blood gases in extraperitoneal laparoscopic urethrocystopexyINTERNATIONAL JOURNAL OF UROLOGY, Issue 8 2002Hasan Kocoglu Abstract Background: The aim of this study was to investigate the effects of extraperitoneal laparoscopy and carbon dioxide insufflation on hemodynamic parameters, arterial blood gases and complications in urethrocystopexy operations. Methods: Twenty-five female patients who underwent extraperitoneal laparoscopic mesh urethrocystopexy operation for the correction of urinary incontinence were allocated to the study. Hemodynamic parameters were noted and blood gas analyzes were performed before the induction of anesthesia, 10 min after induction, 5 and 10 min after the beginning of carbon dioxide insufflation, at the end of carbon dioxide insufflation and 30 min after exsufflation. Results: There was no significant change in mean arterial pressure, peripheral oxygen saturation, arterial carbon dioxide pressure, and arterial oxygen saturation compared to preinsufflation and preinduction values. End-tidal carbon dioxide pressure did not increase above 45 mm/Hg during carbon dioxide insufflation. Arterial oxygen saturation and partial oxygen pressure did not decrease. Subcutaneous emphysema, pneumothorax, pneumomediastinum and pleural effusion were not noted in any patient. Conclusion: We conclude that, extraperitoneal laparoscopic urethrocystopexy is not associated with hemodynamic and respiratory impairment. [source] Ineffectiveness of Local Wound Anesthesia to Reduce Postoperative Pain After Median SternotomyJOURNAL OF CARDIAC SURGERY, Issue 4 2005Diego Magnano M.D. Bupivacaine wound infiltration is frequently used to reduce the pain related to the surgical incision itself. In this randomized study, we investigated the efficacy of bupivacaine local anesthesia after median sternotomy to reduce postoperative pain. Forty-seven patients undergoing major cardiac surgery procedures were allocated randomly to group A (bupivacaine wound infiltration 0.5%; 10 mL, followed by continuous infusion: 10 mg/24 H) or to group C (controls). Extubation time, postoperative arterial blood gases, postoperative pain (assessed by means of a visual analog scale), and morphine consumption were the endpoints of the study. Patients of group C were extubated earlier; blood gases and VAS values were similar in both group. Bupivacaine local analgesia did not improve postoperative pain control after median sternotomy. [source] Effects of sevoflurane on cognitive deficit, motor function, and histopathology after cerebral ischemia in ratsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2009E. EBERSPÄCHER Background: The volatile anesthetic sevoflurane exhibits neuroprotective properties when assessed for motor function and histopathology after cerebral ischemia in rats. Damage of hippocampal neurons after ischemia relates to a number of cognitive deficits that are not revealed by testing animals for motor function. Therefore, the present study evaluates cognitive and behavioral function as well as hippocampal damage in rats subjected to cerebral ischemia under sevoflurane compared with fentanyl/nitrous oxide (N2O)/O2 anesthesia. Methods: Thirty-four rats were trained for 10 days using a hole-board test to detect changes in cognitive and behavioral function. Rats were randomly assigned to the following groups: (A) sham/fentanyl/N2O/O2 (n=7); (B) ischemia/fentanyl/N2O/O2 (n=10); (C) sham/2.0 vol% sevoflurane in O2/air (n=7); and (D) ischemia/2.0 vol% sevoflurane in O2/air (n=10). Cerebral ischemia was produced by unilateral common carotid artery occlusion combined with hemorrhagic hypotension (mean arterial blood pressure 40 mmHg for 45 min). Temperature, arterial blood gases, and pH were maintained constant. Cerebral blood flow was measured using laser-Doppler flowmetry. After surgery, cognitive and behavioral function was re-evaluated for 10 days. On day 11, the brains were removed for histopathologic evaluation (hematoxylin/eosin-staining). Results: Cognitive testing revealed deficits in declarative and working memory in ischemic rats anesthetized with fentanyl/N2O. Rats anesthetized with sevoflurane during ischemia showed a significantly better outcome. Hippocampal damage was significantly worse with fentanyl/N2O. Conclusion: The present data add to previous investigations showing that sevoflurane prevents a deficit in cognitive function and histopathological damage induced by cerebral ischemia in rats. [source] Effect of mivazerol, a ,2 -agonist, on striatal norepinephrine concentration during transient forebrain ischemia in rats,ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2008T. KIMURA Background: We have previously reported that mivazerol, a ,2 -agonist, possibly provides neuroprotection against transient forebrain ischemia in rats. This study was designed to investigate the ability of mivazerol to attenuate ischemia-induced increase in striatal norepinephrine concentration after transient forebrain ischemia in rats. Methods: Male Sprague,Dawley rats, anesthetized with halothane, were assigned to one of three groups (n=10 each); control (C, normal saline 1 ml/kg), mivazerol 20 ,g/kg (M20), and 40 ,g/kg (M40) groups. Monitored variables included temporal muscle temperature (maintained at 37.5±0.1 °C), electroencephalogram, systolic/diastolic blood pressure, heart rate, arterial blood gases, and blood glucose concentrations. Thirty minutes after subcutaneous drug administration, forebrain ischemia was induced with hemorrhagic hypotension (systolic arterial pressure: 40,50 mmHg) and bilateral carotid artery occlusion for 10 min, and then the brain was reperfused. Norepinephrine concentration in the interstitial fluids in the striatum was analyzed using in vivo microdialysis in combination with high-performance liquid chromatography. Results: Ischemia resulted in a prompt increase in norepinephrine concentrations in the striatum in all groups. However, there were no significant differences in norepinephrine concentrations in the striatum between the three groups at any period. Conclusions: Our results indicate that mivazerol did not attenuate ischemia-induced increase in striatal norepinephrine concentration. This suggests that the possible neuroprotective property of mivazerol is not related to inhibition of norepinephrine release in the brain. [source] Arterial oxygen tension increase 2,3 h after hyperbaric oxygen therapy: a prospective observational studyACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2007B. Ratzenhofer-Komenda Background:, Inhalation of hyperbaric oxygen (HBO) has been reported to decrease arterial oxygen tension (PaO2) in the early period after exposure. The current investigation aimed at evaluating whether and to what extent arterial blood gases were affected in mechanically ventilated intensive care patients within 6 h after HBO treatment. Methods:, Arterial blood gases were measured in 11 ventilated subjects [nine males, two females, synchronized intermittent mandatory ventilation (SIMV) mode] undergoing HBO therapy for necrotizing soft tissue infection (seven patients), burn injury (two patients), crush injury (one patient) and major abdominal surgery (one patient). Blood gases were obtained with the patients in the supine position under continuous analgesia and sedation before the hyperbaric session (baseline), during isopression, after decompression, after each transport, and 1, 2, 3 and 6 h after exposure. Heart rates and blood pressures were recorded. Intensive care unit (ICU) ventilator settings remained unchanged. Transport and chamber ventilator settings were adjusted to baseline with maintenance of tidal volumes and positive end-expiratory pressure (PEEP) levels. The hyperbaric protocol consisted of 222.9 kPa (2.2 absolute atmospheres) and a 50-min isopression phase. The paired Wilcoxon's test was used. Results:, Major findings (median values, 25%/75% quantiles) as per cent change of baseline: PaO2 values decreased by 19.7% (7.0/31.7, P < 0.01) after 1 h and were elevated over baseline by 9.3% (1.5/13.7, P < 0.05) after 3 h. SaO2, alveolar-arterial oxygen tension difference and PaO2/FiO2 ratio behaved concomitantly. Acid-base status and carbon dioxide tension were unaffected. Conclusion:, Arterial oxygen tension declines transiently after HBO and subsequently improves over baseline in intensive care patients on volume-controlled mechanical ventilation. The effectiveness of other ventilation modes or a standardized recruitment manoeuvre has yet to be evaluated. [source] Pilot study of pentoxifylline in hepatopulmonary syndrome,LIVER TRANSPLANTATION, Issue 8 2008Rajasekhar Tanikella Hepatopulmonary syndrome (HPS) results when chronic liver disease or portal hypertension causes intrapulmonary microvascular dilatation with hypoxemia. In experimental HPS, tumor necrosis factor alpha (TNF-,) overproduction contributes to vasodilatation, which is improved by pentoxifylline, a TNF-, inhibitor. The effectiveness of pentoxifylline in humans is unknown. The aim of this open-label, single-arm clinical trial was to assess the efficacy and tolerability of pentoxifylline in patients with cirrhosis and advanced HPS undergoing liver transplantation evaluation. Nine adults with cirrhosis and moderate to severe HPS were enrolled. All patients had an initial 2-week titration to a target dose of pentoxifylline of 400 mg by mouth every 8 hours, which was continued for 6 weeks. Baseline and follow-up arterial blood gases and TNF-, levels were evaluated. Adverse effects and tolerability were assessed. The 9 patients had a mean age of 55 ± 10 years, and 67% were female. The most common causes of cirrhosis were hepatitis C virus and alcohol (55%). The mean Model for End-Stage Liver Disease score was 11 (range, 6-19), and patients had advanced hypoxemia [mean partial pressure of arterial oxygen (PaO2) = 54 ± 12 mm Hg, mean alveolar-arterial oxygen gradient (A-a PaO2) = 57 ± 15 mm Hg]. Of the 9 patients enrolled, follow-up blood gases were done in 7. There was no significant change in PaO2 (P = 0.3) or A-a PaO2 (P = 0.3) with treatment. Pentoxifylline was poorly tolerated. Nausea (100%) and vomiting (56%) were the predominant side effects, and only a single patient was able to complete full-dose therapy. Treatment with pentoxifylline did not improve arterial oxygenation in advanced HPS, and tolerance was limited by gastrointestinal toxicity. Liver Transpl 14:1199,1203, 2008. © 2008 AASLD. [source] Tubeless combined high-frequency jet ventilation for laryngotracheal laser surgery in paediatric anaesthesiaACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2000G. Ihra Background: High-frequency jet ventilation (HFJV) is an alternative ventilatory approach in airway surgery and for facilitating gas exchange in patients with pulmonary insufficiency. We have developed a new technique of combined HFJV utilising two superimposed jet streams. In this study we describe the application of tubeless supralaryngeal HFJV during laryngotracheal laser surgery in infants and children. Methods: Tubeless combined HFJV characterised by the simultaneous supralaryngeal application of a low-frequency (LF) and a high-frequency (HF) jet stream was evaluated in a clinical study in 10 children undergoing elective laryngotracheal CO2 laser surgery. Additionally, pressure and flow characteristics were determined with the use of a paediatric test lung. HFJV was applied by means of a modified Kleinsasser laryngoscope with integrated metal injectors. In addition to pulse oximetry, monitoring of ECG, heart rate and blood pressure, supraglottic airway pressure was measured and arterial blood gases were analysed. Results: Tubeless combined HFJV was used in 10 infants and children (mean age 4.6 yr, range 2 months,10 years) undergoing 17 consecutive endoscopic procedures with CO2 laser microsurgery of the larynx or the trachea under general anaesthesia. The mean duration of supralaryngeal HFJV was 46 min (range 15,75 min). Mean driving pressures of the HF and the LF jet streams were 0.75 bar and 0.95 bar, respectively. Inspiratory oxygen ratios were in the range 0.4,1.0. HFJV resulted in mean PaO2 and PaCO2 values of 19.7 kPa and 6.1 kPa, respectively. No complications during HFJV were observed. In the test lung, combined HFJV applied with driving pressures of 0.7,1.0 bar and 0.9,1.2 bar for HF and LF jet ventilation, respectively, resulted in maximum peak and baseline distal airway pressures of 17.6 cm H2O and 5.4 cm H2O, respectively. Conclusion: The application of the combined double frequency HFJV was effective in maintaining gas exchange in the presence of laryngeal or tracheal stenoses. It provided good visibility of anatomical structures and offered space for surgical manipulation, avoiding the use of combustible material inside the larynx or trachea. [source] Nitric oxide donor increases cerebral blood flow and oxygenation during kainic acid-induced seizures in newborn rabbitsPEDIATRICS INTERNATIONAL, Issue 3 2002Yukito Takei Abstract Background: We investigated the hypothesis that sodium nitroprusside (SNP), a nitric oxide (NO) donor, increased the cerebral blood flow and oxygenation during kainic acid (KA)-induced seizures in newborn rabbits. Methods: After KA administration (i.v. 12 mg/kg) to induce seizures, either 1.2 mg/kg SNP (SNP group, i.v., n = 6) or 1 mL normal saline (vehicle group, i.v., n = 6) was given. Regional cerebral blood flow (rCBF), cerebral oxyhemoglobin (oxy-Hb), deoxyhemoglobin (deoxy-Hb), total hemoglobin (t-Hb), mean arterial blood pressure (MABP), heart rate (HR) and electroencephalography (EEG) were continuously monitored throughout the experiment, lasting at least 60 min after the KA administration. Results: The value for rCBF was greatly increased during seizures in the SNP group than in the vehicle group. The values for oxy-Hb and t-Hb were significantly increased, and deoxy-Hb was significantly decreased. There were ameliorations of cerebral oxygenation in the SNP group during the acute phase of seizures in the neonatal animals, compared with the vehicle group. There were no significant differences in the MABP, HR, arterial blood gases, rectal and brain temperatures, blood hemoglobin concentrations, blood glucose levels, the latencies to first abnormal discharges in EEG, the total sum of the duration of abnormal discharges in EEG and the incidences of subclinical electric status epileptics between the two groups. Conclusions: These results suggest that the treatment with SNP contributed to the increases in cerebral blood flow and oxygenation, and that EEG abnormalities were unchanged by the treatment with SNP during neonatal seizures. [source] Improved lung function after thoracocentesis in patients with paradoxical movement of a hemidiaphragm secondary to a large pleural effusionRESPIROLOGY, Issue 5 2007Lee-Min WANG Background and objectives: Previous studies have shown little or no improvement in pulmonary function and arterial blood oxygenation after therapeutic thoracocentesis. This study investigated changes in pulmonary function, arterial blood gases and dyspnoea after therapeutic thoracocentesis in patients with paradoxical movement (PM) of a hemidiaphragm due to pleural effusion. Methods: Twenty-one patients with pleural effusion and PM of a hemidiaphragm and 41 patients with pleural effusion but without paradoxical movement (NPM) were studied before and 24 h after thoracocentesis. Lung function measurements included lung mechanics, blood gas exchange and the Borg dyspnoea scale. Results: At thoracocentesis a mean of 1220 mL of pleural fluid was removed from the PM group and 1110 mL from the NPM group. Post-thoracocentesis the PM group showed small but significant improvement (P < 0.05) in FEV1 (63% vs 73%), FVC (67% vs 77%), PaO2 (66 mm Hg vs 73 mm Hg), A-a O2 gradient (38 mm Hg vs 30 mm Hg), and the Borg scale (5.1 vs 2.1). The NPM group showed no significant change in any parameter. Conclusions: Statistically significant improvement in pulmonary function following thoracocentesis was observed in patients with pleural effusion and PM of the hemidiaphragm. Patient selection may therefore explain the different outcomes of thoracocentesis reported in previous studies. [source] Mechanisms by which systemic salbutamol increases ventilationRESPIROLOGY, Issue 2 2006Antony E. TOBIN Background and objective: Salbutamol (SAL) has systemic effects that may adversely influence ventilation in asthmatic patients. The authors sought to determine the magnitude of this effect and mechanisms by which i.v. SAL affects ventilation. Methods: A prospective study of nine healthy subjects (eight men, one woman; age 23 ± 1.4 years (SD)) was undertaken. Each subject received i.v. SAL at 5, 10 and 20 µg/min each for 30 min at each dose and was observed for 1 h post infusion. Minute ventilation (V,E), oxygen consumption (V,O2), CO2 production (V,CO2), occlusion pressure (P0.1), heart rate, blood pressure, respiratory rate, glucose, arterial blood gases, lactate and potassium (K+) were recorded at baseline and at 30-min intervals. The effect of 100% oxygen on V,E and P0.1 during SAL infusion at 20 µg/min was observed. Results are expressed as mean ± SEM. Results: V,E was significantly increased at 20 µg/min SAL (37.8 ± 12.1%, P = 0.01), as were V,O2 (22.5 ± 5.1%, P < 0.01) and V,CO2 (40.9 ± 10.6%, P < 0.01). Ventilation was in excess of metabolic needs as demonstrated by a rise in the respiratory exchange ratio (0.87 ± 0.03 to 0.99 ± 0.04, P < 0.05). Serum lactate rose by 124 ± 30.4% from baseline to 20 µg/min (1.1 ± 0.1 to 2.3 ± 0.25 mmol/L, P < 0.01) and base excess decreased (0.89 ± 0.56 to vs. ,1.75 ± 0.52 mmol/L, P < 0.01) consistent with a lactic acidosis contributing to the excess ventilation. There was no significant differences in V,E or P0.1 with FIO2 = 1.0, suggesting peripheral chemoreceptor stimulation was not responsible for the rise in V,E. At 20 µg/min SAL, K+ fell significantly from baseline (3.8 ± 0.06 to 2.8 ± 0.09 mmol/L, P < 0.001). Conclusion: Systemic SAL imposes ventilatory demands by increasing metabolic rate and serum lactate. This may adversely affect patients with severe asthma with limited ventilatory reserve. [source] Acute mountain sickness is associated with sleep desaturation at high altitudeRESPIROLOGY, Issue 4 2004Keith R. BURGESS Objective: This study was intended to demonstrate a biologically important association between acute mountain sickness (AMS) and sleep disordered breathing. Methodology: A total of 14 subjects (eight males, six females aged 36 ± 10 years) were studied at six different altitudes from sea level to 5050 m over 12 days on a trekking route in the Nepal Himalaya. AMS was quantified by Lake Louise (LL) score. At each altitude, sleep was studied by 13 channel polysomnography (PSG). Resting arterial blood gases (ABG) and exercise SaO2 were measured. Ventilatory responses (VR) were measured at sea level. Individual data were analysed for association at several altitudes and mean data were analysed for association over all altitudes. Results: ABG showed partial acclimatization. For the mean data, there were strong positive correlations between LL score and altitude, and periodic breathing, as expected. Strong negative correlations existed between LL score and PaO2, PaCO2, sleep SaO2 and exercise SaO2, but there was no correlation with sea level VR. There were equally tight correlations between LLs/PaO2 and LL score/sleep SaO2. The individual data showed no significant correlations with LL score at any altitude, probably reflecting the non-steady state nature of the experiment. In addition, mean SaO2 during sleep was similar to minimum exercise SaO2 at each altitude and minimum sleep SaO2 was lower, suggesting that the hypoxic insult during sleep was equivalent to or greater than walking at high altitude. Conclusions: It is concluded that desaturation during sleep has a biologically important association with AMS, and it is speculated that under similar conditions (trekking) it is an important cause of AMS. [source] Fluid shifts during cardiopulmonary bypass with special reference to the effects of hypothermiaBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 7 2000J. K. Heltne Background Generalized overhydration, oedema and organ dysfunction occurs in patients undergoing open heart surgery using cardiopulmonary bypass (CPB) and hypothermia. Inflammatory reactions induced by contact between blood and the foreign surfaces of the extracorporeal circuit are commonly held responsible for the disturbances in fluid balance (,capillary leak syndrome'). Using the CPB circuit reservoir as a fluid gauge (measuring continuous extracorporeal blood volume), fluid shifts between the intravascular and the extravascular space, and differences between normothermic and moderately hypothermic CPB, were examined. Methods Piglets were placed on CPB (thoracotomy) under general anaesthesia. In the normothermic group (n = 7) the core temperature was kept at 38°C before and during 2 h on CPB, whereas in the hypothermic group (n = 7) the temperature was lowered to 29°C during bypass. In addition to accurate recording of fluid during operation, the extracorporeal blood volume was kept constant by maintaining a certain blood level in the CPB circuit's reservoir. Acetated Ringer was used as priming solution in the CPB, as maintenance fluid and for adding fluid to the reservoir if necessary. Results Cardiac output, serum electrolytes and arterial blood gases were all similar in the two groups. Haematocrit fell significantly following the start of CPB in both groups. The reservoir fluid level fell markedly in both groups necessitating fluid supplementation. This extra fluid requirement was transient in the normothermic group, but persisted in hypothermic animals. At the end of 2 h of CPB the hypothermic animals had received seven times more extra fluid than the normothermic pigs. Conclusion There were strong indications of a greater fluid extravasation induced by hypothermia. The model described, using the PBC circuit reservoir as a fluid gauge, provides the opportunity for further study of fluid volume shifts, their causes and potential ways to manipulate fluid pathophysiology related to hypothermia and to PBC. © 2000 British Journal of Surgery Society Ltd [source] | |||||||||||||