bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of arterial carbon dioxide on cerebral oxygenation and haemodynamics during ECMO in normoxaemic and hypoxaemic piglets
Authors: LIEM K. D. , KOLLÉE L. A. A. , HOPMAN J. C. W. , DE HAAN A. F. J. , OESEBURG B. 
Published: January 2009

Objective. To investigate the cerebrovascular response to changes in arterial CO2 tension during extracorporeal membrane oxygenation (ECMO) in normoxaemic and hypoxaemic piglets.Methods. Four groups of six anaesthetized, paralysed and mechanically ventilated piglets: group 1 ‐ normoxaemia without ECMO, group 2 ‐ ECMO after normoxaemia, group 3 ‐ hypoxaemia without ECMO, and group 4 ‐ECMO after hypoxaemia, were exposed successively to hypercapnia and hypocapnia. Changes in cerebral concentrations of oxyhaemoglob in (cO2Hb), deoxyhaemoglobin (cHHb), (oxidized ‐ reduced) cytochrome aa3 (cCyt. aa3) and blood volume (CBV) were continuously measured using near infrared spectrophotometry. Heart rate, arterial O2 saturation, arterial blood pressure, central venous pressure, intracranial pressure (ICP) and left common carotid artery blood flow (LCaBF) were measured simultaneously.Results. Hypercapnia resulted in increased CBV, cO2Hb and ICP in all groups, while cHHb was decreased. No changes in LCaBF were found. Hypocapnia resulted in decreased cO2Hb and increased cHHb except in group 3. LCaBF decreased in all groups except group 2. CBV decreased only in groups 2 and 4. No effect on ICP was observed in any of the groups. The other variables showed no important changes either during hypercapnia or hypocapnia. ECMO after hypoxaemia resulted in a greater response of cO2Hb and cHHb during hypocapnia. The effect of hypercapnia on CBV while on ECMO was greater than without ECMO.Conclusion. Since cerebrovascular reactivity to CO2 remains intact during ECMO in piglets, it is important to keep arterial CO2 tension stable and in normal range during clinical ECMO.
Oxygen availability in critical illness ‐ An investigation using the oxygen status algorithm
Authors: MORGAN J. , KANOWSKI D. 
Published: January 2009

Using the oxygen status algorithm of Siggaard‐Andersen to derive 2, 3‐diphosphoglycerate concentrations and parameters of oxygen extractivity, 143 arterial blood specimens from 73 ICU patients were compared with 119 venous blood specimens from 119 healthy outpatients. The venous extractivity parameters were calculated by arbitrarily assigning an oxygen tension of 90 mmHg to each specimen.There were no significant differences in 2, 3‐diphosphoglycerate, but the mean concentration of extractable oxygen corrected for low haemoglobin values (cxlcHb) was significantly greater in the ICU patients (males: 0. 017 ± 0. 004 mmol/g, females: 0. 016 ± 0. 004 mmol/g) than in the healthy outpatients (males and females: 0. 014 ± 0. 001 mmol/g, p < 0. 05). This reduction in haemoglobin‐oxygen affinity was attributed to the high incidence of acidaemia in the ICU specimens (mean pH 7. 36 ± 0. 08), despite a reduced mean 2, 3‐diphosphoglycerate concentration in the ICU acidaemic specimens (when pH < 7. 35, mean 2, 3‐diphosphoglycerate concentration was 4. 9 ± 1. 6 mmol/L; when 7. 35 < pH < 7. 45: mean 2, 3‐diphosphoglycerate concentration was 5. 7 ± 1. 6 mmol/L, p < 0. 05). Hypophosphataemia had no demonstrable effect on 2, 3‐diphosphoglycerate concentrations or extractivity parameters in the ICU patients. We conclude that oxygen release from haemoglobin to the tissues in critical illness is enhanced because of a tendency to acidaemia.
Clinical assessment of oxygen delivery and consumption during hypotensive anaesthesia ‐ A clinical application of The Deep Picture™
Authors: UEDA N. , MUTEKI T. , YAMADA S. , MASUDA Y. 
Published: January 2009

Usual evaluation of the relationship between oxygen delivery (DO2) and oxygen uptake (VO2) is based on the arterial oxygen tension (pO2), oxygen saturation (sO2), haemoglobin concentration (ctHb), the same indicators in mixed venous blood and cardiac output, sometimes supplemented by the expiratory carbon dioxide concentration. And, so far, the relationship among DO2, VO2 and the new parameters for an evaluation of oxygen status (oxygen extraction tension: pK, concentration of extractable oxygen: cx, oxygen compensation factor: Qx) (1) has not been discussed enough.Therefore, this study was designed to evaluate whether the new parameters give the clinically significant information to analyse the relationship between DO2 and VO2 during the acute haemodynamic change with intentionally induced hypotension in anaesthetized adult patients.
Oxygen status during haemodialysis
Authors: NIELSEN A. L. , JENSEN H. Æ. , HEGBRANT J. , BRINKENFELDT H. , THUNEDBORG P. ,   THE CORD‐GROUP
Published: January 2009

Hypoxia during haemodialysis, mainly acetate, has been reported several times. In our study we have monitored oxygen status during 258 bicarbonate haemodialyses. A significant drop below 80 mmHg in mean oxygen tension occurred. Mean oxygen saturation reflected this drop but did not reach levels below 90%. The mean oxygen concentration was on the whole critical low, though slightly increasing during each haemodialysis session due to ultrafiltration.It is concluded that both hypoxia and hypoxaemia do occur during bicarbonate haemodialysis. To a group of patients generally having limited cardiac reserves, a poor oxygen status is a potentially serious complication to haemodialysis. Monitoring oxygen status is thus advisable.
Permissive hypercapnia in ARDS and its effect on tissue oxygenation
Authors: HICKLING K. G. , JOYCE C. 
Published: January 2009

Many experimental studies have shown that mechanical ventilation with high tidal volumes (V1) or with a low end‐expiratory volume allowing repeated end‐expiratory collapse, can result in acute parenchymal lung injury and probably an inflammatory response. Low volume ventilation with permissive hypercapnia has been used in an attempt to avoid such injury in ARDS.Such management can affect oxygenation in many complex ways. The right‐shift of the haemoglobin‐oxygen dissociation curve during acute respiratory acidosis may increase venous oxygen tension (PvO2) which could allow increased O2 uptake in ischaemic tissues. Acidosis may reduce intrapulmonary shunt (Qs/Qt) by potentiating hypoxic pulmonary vasoconstriction, and there may also be direct and autonomically mediated effects of hypercapnia both on the lung vasculature and on the airways. Cardiac output usually increases as a consequence of hypercapnia and perhaps as a result of reduced intrathoracic pressure, further increasing Pv02 and CvO2, but the increase in cardiac output (CO) may tend to increase Qs/Qt as flow increases preferentially in unventilated lung. The reduction of mean airway pressure may directly increase Qs/Qt. Hypercapnia may affect the distribution of systemic blood flow both within organs and between organs.Limited clinical studies suggest that tissue oxygenation is usually unchanged or improved during permissive hypercapnia with increased CO2 reduced arterio‐venous O2 content difference and reduced blood lactate concentration. However, acute hypercapnia per se can reduce lactate production. Further studies are required of this complex issue.
Pentoxifylline and oxygen consumption in severe sepsis ‐ A preliminary report
Authors: CASTAÑON‐GONZALEZ J. A. , EID‐LIDT G. , WACHER N. , GALLEGOS‐PEREZ H. , MIRANDA‐RUIZ R. 
Published: January 2009

Objective: To demonstrate that pentoxifylline (PTX) and not placebo improves oxygen consumption (VO2) in critically ill patients with severe sepsis.Setting: Multidisciplinary intensive care unit in a university affiliated hospital.Design: A randomized, double blinded clinical trial comparing 300 mg of PTX administered in a 120 min iv infusion with an identically looking placebo.Patients: 13 patients (9 men and 4 women) average age 39 (24–62) years old received PTX, and 12 patients (5 men and 7 women) average age 38 (21–83) years old received placebo. All satisfied ACCP/SCCM criteria for severe sepsis.Measurements and interventions: Patients fulfilling criteria for severe sepsis were identified on admission, cardiac output, DO2 and VO2 were measured by thermodilution and standard oximetric technics after adequate volume replacement at baseline, 60 and 120 during infusion. F‐test of analysis of variance was used to test hypothesis about differences of DO2 and VO2 by group, by time and for the interaction terms, a “p” value <0. 05 was considered significant.Results: Evaluation of baseline measurements of both groups revealed no significant difference in any haemo‐dynamic function or oxygen transport variables. The average V02 difference (0–120 min) between groups was 21 mL/min · m2 and it was higher in the experimental group, however, this difference was non significant.Conclusion: We think that the trend in VO2 followed by the experimental group is clinically important. If this difference is sustained we will probably be able to demonstrate our hypothesis.
Optimal values for oxygen transport during hypothermia in sepsis and ARDS
Authors: PERNERSTORFER T. , KRAFFT P. , FITZGERALD R. , FRIDRICH P. , KOC D. , HAMMERLE A. F. , STELTZER H. 
Published: January 2009

Mild hypothermia (33 °C to 35. 5 °C) is reported to improve oxygenation and survival in patients with lung failure (1). Although hypermetabolism may account for about 50% of the ventilatory demand in ARDS patients, the concept of reducing oxygen consumption (VO2) by lowering metabolic rate, has only recently gained attention (2). Our study was aimed to test whether mild hypothermia established by continuous veno‐venous haemofiltration (CVVHF), could optimize values for oxygen kinetics in ARDS patients.Overall, we recruited 27 patients with ARDS and sepsis. Prior initiation of CVVHF patients had to meet the following criteria: a) Murray score >2. 5, and hypoxaemia with PaO2/FIO2 <200, b) hyperthermia of >38 °C, c) cardiovascular instability requiring inotropic support. Evaluation of cardio‐respiratory data was performed within four different phases (1= before, II + III during and IV= after CVVHF) every 6 hours. Core temperature as derived from the thermistor of pulmonary artery catheter was aimed to be between 35. 0 °C anil 36. 5 °C.Optimal values for oxygen delivery (DO2) (>550 mL/min/m2) and VO2 (>160 mL/min/m2) were defined according to Shoemaker and achieved by fluid loading, transfusion and inotropic support (3).Septic shock occurred in 10 of 14 nonsurvivors (nons) and 2 of 13 survivors (surv). Mean values for DO2 and VO2 were calculated at different body temperature ranges. While at 37 °C DO2 was identical between surv and nons, (663±128 versus 666±127 mean±SD) moderate hypothermia led to a small decrease of DO2 in surv and a significant decrease in nons (632±134 versus 605±128 mL/min/m2) at 35 °C. Concerning VO2 during hypothermia, there was a significant drop in nonsurvivors while in survivors the decrease was less pronounced.We could demonstrate a decrease in DO2 and VO2 during mild hypothermia during CVVHF. However, decreases in nonsurvivors were more pronounced than in survivors. These results suggest that the inability to achieve optimal values for DO2 and VO2 during mild hypothermia induced by CVVHF could serve as a prognostic sign for fatal outcome. Although oxygen consumption is decreased during hypothermia, hypoxaemia may result due to alterations of the oxygen transport on a cellular basis. The relationship between oxygen transport and temperature during CVVHF therefore deserves further studies.
Effects of catecholamines on regional perfusion and oxygenation in critically ill patients
Authors: MEIER‐HELLMANN A. , REINHART K. 
Published: January 2009

Multiple organ failure is the major cause of death in patients with sepsis. Bacterial translocation from the gut is considered to induce and maintain sepsis. Therefore, the splanchnic region plays an important role in the pathogenesis and treatment of sepsis. There is evidence for a very high risk of imbalance between oxygen delivery and oxygen consumption especially in the splanchnic region. Consequently, there is a crucial interest whether it is possible to influence the splanchnic perfusion by specific catecholamines. Unfortunately, only a few, conflicting studies have looked at the effects of the various catecholamines on regional blood flow. Therefore, a clear recommendation for a specific catecholamine regimen in septic shock is impossible. Furthermore, it is unknown whether the choice of a specific catecholamine in the treatment of septic shock affects the patient's outcome. In most patients, the use of vasopressors is indispensable because adequate haemodynamic perfusion pressure is not achieved with fluid therapy alone. The negative effects of vasopressors on splanchnic perfusion are known from studies carried out under non septic conditions. Norepinephrine and dopamine in doses of 10 μg/kg/min in septic animals are without negative effects on splanchnic perfusion. Preliminary results show a decrease in splanchnic oxygenation in patients with septic shock treated with epinephrine.Catecholamines with beta mimetic effects are often used to increase DO2. The question as to whether dobuta‐mine or dopamine should be used first in treatment of septic shock cannot be answered yet.Whether treatment with low dose dopamine or dopexamine actually improves renal function and splanchnic oxygenation is the purpose of ongoing studies.
Lactate, pH, and blood gas analysis in critically ill patients
Authors: WALDAU T. , LARSEN V. H. , BONDE J. , FOGH‐ANDERSEN N. 
Published: January 2009

To obtain information about the relationship between different types of circulatory insufficiency, a series of oxygen parameters and plasma lactate, we have performed a pilot study comprising five patients with circulatory insufficiency.Plasma lactate was measured on a Stat Profile 7 (NOVA Biomedical, USA) and pH/blood gases on an ABL™ 520 (Radiometer Medical A/S, Denmark).Plasma lactate seems to be inversely related to base excess (BE), whereas no relationship to venous oxygen tension pO2(v) of the vein draining the inadequately perfused region seemed to exist. In one patient we made simultaneous measurements from v. cava inferior., v. cava superior., a. pulmonalis and a. radialis. Simultaneously sampled plasma lactate from different sites differed up to 0. 6 mmol/L with the highest value obtained from v. cava inferior.This pilot study indicates that the increase of plasma lactate may vary with the type of circulatory disturbance and the sampling site.
Improvement of arterial oxygenation by selective infusion of prostaglandin E1 to ventilated lung during one‐lung ventilation
Authors: Chen T.‐L. , Ueng T.‐H. , Huang C.‐H. , Chen C.‐L. , Haung F.‐Y. , Lin C.‐J. 
Published: January 2009

Background:One‐lung anesthesia provides a better surgical field for thoracic procedures but also impairs the arterial oxygenation and venous admixture. During one‐lung ventilation, pulmonary vasoconstriction is assumed to be present within both ventilated and collapsed lungs. We propose that arterial oxygenation could be optimized by offsetting the vasoconstriction within the microcirculation of ventilated lung.Method:In an anesthetized dog model, incremental doses of prostaglandin E1 (PGE1) were selectively infused into the main trunk of the pulmonary artery of the ventilated lung after one‐lung ventilation for 60 min (PGE1 group, n=9). Arterial oxygenation and calculated venous admixture (Qs/Qt) was also assessed in a time‐course control group (Control group, n =5). During two‐lung ventilation (FIO2: 0.66), arterial PO2 and venous admixture was 44.22 ± 3.5 kPa and 10.7±2.3%, respectively. One‐lung ventilation (FIO2: 0.66) with left lung collapsed reduced arterial PO2 to 11.6±1.7 kPa and increased venous admixture to 40.7±5.8% (P<0.001). Venous O2 tension also decreased from 6.3±0.7 kPa to 5.0±0.6 kPa with a slight increase in mean pulmonary artery pressure and pulmonary vascular resistance (P <0.05).Results: During selective infusion of PGE1 at a dose of 0.04 to 0.2 μg kg‐1 min‐1, there was a dose‐dependent improvement in arterial PO2 with a parallel reduction of venous admixture during one‐lung ventilation. Arterial PO2 increased to a maximum of 23.0±4.3 kPa, and the venous admixture decreased significantly to a minimum of 27.4±4.2% by PGE1 at a dose of 0.04‐0.4 μg kg‐1 min‐1 (P<0.01). PGE1 resulted in a small increase in cardiac output and decreases of pulmonary pressure and pulmonary vascular resistance at a relatively high dose of 0.4 μg kg‐1 min‐1 during selective infusion (P<0.05).Conclusion: These results suggest that a selective pulmonary artery infusion of PGE1 to the ventilated lung within the dose range of 0.04‐0.4 μg kg‐1 min‐1 is practical and effective to improve arterial oxygenation and reduce venous admixture during one‐lung ventilation.
Does epidural sufentanil provide effective analgesia per‐and postoperatively for abdominal aortic surgery?
Authors: Broekema A. A. , Kuizenga K. , Hennis P. J. 
Published: January 2009

To assess the efficacy of epidural sufentanil in providing per‐and postoperative analgesia, 40 patients undergoing elective abdominal aortic surgery received either 50 μg sufentanil in 10 ml normal saline solution (n=20, ES group) or 10 ml normal saline (n=20, control group) via a thoracic epidural catheter. The study solution was given (double‐blind and at random) after the patients had been anaesthetized with i.v. midazolam, sufentanil and vecuronium. Anaesthesia was maintained with 60% nitrous oxide in oxygen and halothane at a 1% inspiratory concentration. When patients showed signs of inadequate analgesia, supplementary doses of 25 μg sufentanil were given i.v. The number of patients requiring additional i.v. sufentanil differed significantly between the two groups: 5 out of 20 patients in the ES group vs 13 out of 20 patients in the control group required additional sufentanil (P<0.05). The mean dose administered i.v. did not differ significantly between the two groups: 105±109.5 μg vs 138.5±126.9 μg (mean±SD) in 5 and 13 patients, respectively. No cardiovascular changes were observed after the epidural bolus dose.Postoperative analgesia, consisting of a continuous epidural infusion of 50 μg sufentanil in 50 ml bupivacaine 0.125% at a rate of 6–10 ml/h after a bolus dose of 10 ml of this solution, was adequate in the majority of patients, as determined by VAS‐scores assessed during the epidural treatment (4.3±1.5 days).
Haemodynamic effects of high‐dose vecuronium compared with pancuronium in beta‐blocked patients with coronary artery disease during fentanyl‐diazepam‐nitrous oxide anaesthesia
Authors: Husby P. , Gramstad L. , Rosland J. H. , Vamnes J. S. , Segadal L. 
Published: January 2009

Background. Different combinations of neuromuscular blockers and opioids have been used in patients with angina pectoris to provide cardiovascular stability and reduce risk of myocardial ischaemia during anaesthesia.Methods. We have compared the haemodynamic effects of high‐dose vecuronium (0.3 mg kg‐1) with those of a standard dose of pancuronium (0.1 mg kg‐1) in patients scheduled for coronary artery bypass grafting during fentanyl‐diazepam‐nitrous oxide anaesthesia. All patients were receiving beta‐adrenergic blocking agents. The given doses of vecuronium and pancuronium are equieffective with respect to duration of neuromuscular blockade.Results. During a 25‐min experimental period following the administration of the randomly selected drug, no significant changes in the haemodynamic parameters were observed in the vecuronium group. The administration of pancuronium, however, resulted in a significant mean increase in heart rate (20%), rate‐pressure product (23%) and cardiac index (21%). Following endotracheal intubation in the pancuronium group, we observed an additional significant increase in mean arterial pressure and rate‐pressure product.Conclusion. High‐dose administration of vecuronium has minimal haemodynamic effects and may thus offer a better alternative than pancuronium for long‐lasting neuromuscular blockade in patients with coronary artery disease during fentanyl‐diazepam‐nitrous oxide anaesthesia.
Haemodynamic interaction of high‐dose fentanyl and increasing doses of vecuronium in patients undergoing myocardial revascularization
Authors: Couture P. , Boudreault D. , Girard D. , Plante F. , McKenty S. , St‐Pierre J. , Poirier N. L. 
Published: January 2009

Background. Bradyarrhythmia has been reported with vecuronium when given with high dose narcotics. We hypothesized that if the bradycardic response is dependent on a vagal reaction mediated by narcotics, it should be independent of the vecuronium dose. A dose‐related response of vecuronium on heart rate (HR) would be in favour of a chronotropic action of this agent.Methods. We examined three induction techniques using high doses of fentanyl in which vecuronium was given in increasing doses. In addition, a reference group received a low dose of atracurium. Forty patients scheduled for elective CABG surgery were anaesthetized with fentanyl (50 μg) given over 5 min, and were randomly assigned to receive either 0.056, 0.14, 0.28 mg/kg of vecuronium or 0.28 mg/kg of atracurium. Haemodynamic measurements were obtained at the following intervals: before induction (time 0), after the administration of fentanyl (at 5 min), and 1, 2 and 5 min after tracheal intubation (at 10, 11 and 15 min).Results. In vecuronium‐treated groups, there were significant decreases in HR, mean arterial pressure, and cardiac output (P<0.05). There were no differences between the three vecuronium groups. Although the atracurium‐treated group displayed no significant haemodynamic changes, 2 patients of this group developed HR < 40 bpm.Conclusions. Over the range of vecuronium doses studied, we observed a reduction in HR during induction for CABG surgery with high doses of fentanyl and vecuronium. This effect was not dose dependent and is likely related to a direct effect of a high‐dose narcotic technique and/or due to a vagal stimulation regarding the airway procedure.
Effects of subarachnoid lidocaine, meperidine and fentanyl on somatosensory and motor evoked responses in awake humans
Authors: Fernández‐Galinski S. M. , Monells J. , Espadaler J. M. , Pol O. , Puig M. M. 
Published: January 2009

Although the effects of local anaesthetics (LA) on motor and sensory transmission in the spinal cord have been described, the effects of opioids are controversial. Our aim was to evaluate the action of clinically relevant doses of subarachnoid (SA) meperidine (MP) and fentanyl (FN), on somatosensory (SSEP) and cortical motor evoked responses (CMER) in awake subjects. Thirty ASA I‐II patients scheduled for infra umbilical surgery received SA (N = 10/group): 1 mg/kg lidocaine (LD), 1 mg/kg MP or 25 μg FN. SSEP elicited by stimulation of the posterior tibial nerve at the ankle, and cortical motor evoked response at rest (r‐CMER) and during facilitation (f‐CMER) were obtained prior and 30 min after treatment. Conduction at the proximal segment of the motor nerve (F‐wave) was evaluated by stimulation ot the posterior tibial nerve at the popliteal fossa. Motor/sensory block and side effects were clinically assessed.LD completely abolished SSEP and CMER. At the same dose, MP abolished SSEP in 40% of the patients, while r‐CMER and f‐CMER were absent in 70% and 30%, respectively; in addition, the F‐wave was absent in 50% of the patients. Fentanyl induced small changes in the latencies of SSEP and F‐wave; however, a 28% decrease in the amplitude of the f‐CMER (P<0.05) was observed. Pruritus was present in 60% of patients in the FN group (P<0.006).Our results show that while LD and MP block sensory and motor conduction at the spinal roots, FN seems to decrease the excitability of the spinal interneurons in the corticospinal tract.