[Patient management systems: towards a new era?].
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Database Management Systems↗
Biomedical subjects
A Hoeft
Publications and source records attributed to A Hoeft.
Assessment of cardiovascular volume status by transoesophageal echocardiography and dye dilution during cardiac surgery.
Conventional evaluation of cardiovascular volume status by filling pressures is unreliable in critically ill patients. Measurements of left ventricular end diastolic area index by transoesophageal echocardiography and of intrathoracic blood volume index by dye indicator dilution are new approaches to this problem. In this study, different indices of cardiovascular volume status were analysed to define their relation during the pronounced haemodynamic changes associated with systemic inflammation after cardiopulmonary bypass. Correlations were performed with left ventricular end diastolic area index, intrathoracic blood volume index, central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP). Data from 15 patients receiving coronary artery bypass grafts were compared after induction of anaesthesia and in the intensive care unit. Spearman's correlation coefficient for perioperative absolute changes in left ventricular end diastolic area index and intrathoracic blood volume index was 0.87 (P < 0.05). However, an increase in intrathoracic blood volume index by 125 mL m-2 was necessary to maintain a baseline left ventricular end diastolic area index. Absolute values of all variables varied widely, with the only significant correlation found between CVP and PCWP. Changes in CVP and PCWP did not correlate with changes in left ventricular end diastolic area index or intrathoracic blood volume index. Provided simultaneous baseline measurements are available and a supranormal intrathoracic blood volume index compensates for the haemodynamic changes in systemic inflammation, left ventricular end diastolic area index and intrathoracic blood volume index may substitute for each other during the evaluation of cardiovascular volume status in patients with stable cardiac function.
Anesthesia↗
Fatal rhabdomyolysis and multiple organ failure associated with adjuvant high-dose interferon alfa in malignant melanoma.
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Antineoplastic Agents↗
Acute affect of mitral calve replacement on extravascular lung water in patients receiving colloid or crystalloid priming of cardiopulmonary bypass.
Despite numerous studies on extravascular lung water (EVLW) in patients undergoing coronary artery bypass surgery, few data are available on the perioperative time course of EVLW in patients undergoing mitral valve replacement for mitral valve insufficiency (MVI). We have investigated 26 patients undergoing elective mitral valve replacement in order to determine the influence of the preoperative degree of mitral valve insufficiency (degree III or IV) and the effect of different priming solutions for cardiopulmonary bypass. Crystalloid priming with Ringer's lactate was compared with human albumin priming solution. Measurement of EVLW was performed using the thermo-dye dilution technique, before and 1, 6 and 24 h after surgery. Before operation, EVLW is increased significantly in patients with MVI degree IV (MVI-degree IV) compared with patients with degree III (MVI-degree III) and patients undergoing coronary artery bypass surgery. During the postoperative time course a significant decrease in EVLW was observed in patients with MVI-degree IV whereas in patients with MVI-degree III the amount of EVLW did not change. However, compared with patients undergoing coronary artery bypass surgery, EVLW remained above normal in both groups. There was no interaction between the type of priming solution and the postoperative time course of EVLW, and no differences in respiratory variables or duration of mechanical ventilation were observed between groups.
Adult↗
Pulmonary distribution of alfentanil and sufentanil studied with system dynamics analysis.
We applied a system dynamics approach to the study of the pulmonary distribution of alfentanil and sufentanil in anesthetized pigs and patients, respectively. This method allows estimation of the mean transit time through the lungs and calculation of the volume of distribution of alfentanil in the lungs. In the first part of the study the pulmonary distribution of alfentanil was studied in six anesthetized pigs during three hemodynamic states (control, partial clamping of the inferior vena cave, and complete clamping of the right pulmonary artery). In the second part of the study the pulmonary distribution of sufentanil was studied in 10 patients, scheduled for elective CABG, during and after a constant rate infusion of 10 min. Pulmonary passage of the opioids was characterized by functions of transit times, derived from the pulmonary arterial and systemic arterial concentration curves. Pulmonary distribution volumes were calculated from the mean transit time and pulmonary blood flow. Pulmonary distribution volume of alfentanil during the control measurement was significantly higher (486 +/- 88 ml) than during either partial caval clamping (346 +/- 89 ml, p < 0.05) or right pulmonary artery clamping (336 +/- 56 ml, p < 0.05). There was no change in the extravascular volume of distribution of alfentanil with each hemodynamic state. Pulmonary volume of distribution of sufentanil in the patients was 22.6 (10.9) L. Pulmonary distribution of opioids can be studied using system dynamics analysis, both after bolus injection and during and after infusion. This method can be used for periods beyond the initial passage of the drug through the lungs.
Alfentanil↗
Effects of local restriction of evaporation and moderate local ventilation on thermoregulatory responses in exercising humans.
Ten healthy young men participated in two series of three trials: series 1 (C1) with, or without, local restriction of evaporation (either on the trunk or on the legs) and series 2 (C2) with, or without, local moderate nitrogen ventilation (40 l.min-1) under an impermeable garment (trunk or leg ventilation). After 60-min rest in a thermoneutral environment, the subjects exercised in a warm environment [30 degrees C, 47% relative humidity (rh) during C1 and 29% rh during C2] on a cycle ergometer for 60 min at 70 W during C1 or at 60 W during C2. During C1, local covering with plastic foil did not increase internal temperature, but increased the mean skin temperature with a higher effect in the case of leg restriction. The trunk skin temperature was affected by the leg covering while the leg skin temperature was not changed by the trunk covering. Only the local sweat rate of the trunk was increased by the two restriction conditions. During C2, internal temperature was decreased by local ventilation while mean skin temperature was reduced only by trunk ventilation. The local ventilation affected only trunk skin temperature with a greater decrease during trunk ventilation. Trunk ventilation did not influence the skin temperature of the legs while ventilation of the legs decreased trunk skin temperature. In addition, leg ventilation decreased the sweat rate of the legs. The impermeable suit worn during C2 led to a greater physiological strain compared to the plastic film worn during C1 even with local ventilation under the impermeable garment. As expected, limiting sweat evaporation led to an increase in physiological strain. Microclimate ventilation at a rate of 40 l.min-1 was not sufficient to allow total heat dissipation but allowed 60-min exercise in a warm environment to be completed without excessive heat accumulation. It would appear that ventilation of the trunk locally was the best solution because of the smaller increase in skin temperature and higher sweating capacity of the trunk.
Adult↗
[Measurement of human cerebrovascular circulation. Comparison of Kety-Schmidt technique with the intravenous 133-xenon clearance technique].
UNLABELLED: In this study cerebral blood flow (CBF) was simultaneously measured with the Kety-Schmidt method and the intravenous 133Xe clearance technique. CBF, cerebral metabolic rate of oxygen (CMRO2), and CO2 reactivity of CBF were compared under fentanyl-midazolam anaesthesia and varying paCO2 levels. METHODS: Thirteen male patients were studied before they underwent coronary artery bypass surgery. For measurement of CBF with the Kety-Schmidt inert gas saturation technique, argon was used as indicator instead of nitrous oxide, because argon is less soluble in water and lipid such that arterial and hence organ saturation is attained earlier. Wash-in periods of 10 min were used for all measurements. For measurement of CBF with the intravenous xenon method 10 scintillation detectors placed lateral to the skull and an air detector for calculation of tracer recirculation were used. 10-15 mCi of 133Xe dissolved in physiological saline was injected via a peripheral i.v. cannula. For comparison with the Kety-Schmidt technique CBF15-values representing the flow of the grey and white matter were chosen. CBF was measured simultaneously with both methods under normocapnic (paCO2 43 +/- 3 mmHg), hypocapnic (paCO2 31 +/- 3 mmHg), and under hypercapnic (paCO2 54 +/- 4 mmHg) conditions. RESULTS: All CBF15 values obtained with the intravenous xenon method were significantly lower than the corresponding CBF-values measured with the Kety-Schmidt technique: by 36% under normocapnic, 23% under hypocapnic, and 39% under hypercapnic conditions, respectively. Hence, CMRO2 values calculated from CBF values obtained with the xenon method were reduced to about the same degree as those derived from CBF values measured with the Kety-Schmidt technique. There was no significant correlation between the CBF values of either method (y = 1.82x-8.58,r = 0.76 P = 0.357). Non-linear curve-fitting procedures yielded exponential CBF-paCO2 relationships for both methods, although the relative carbon dioxide reactivity was higher with the Kety-Schmidt technique than with the xenon method (y = 8.14 e0.039x vs y = 10,75 e0.023x). CONCLUSIONS: Most probably due to contamination with radioactivity from slowly perfused extracerebral tissues the intravenous 133Xe-clearance technique underestimates CBF, CMRO2, and cerebrovascular CO2 reactivity, at least when CBF15 values are used as flow parameters.
Adjuvants, Anesthesia↗
[Cardiac output determination with transpulmonary thermodilution. An alternative to pulmonary catheterization?].
UNLABELLED: Cardiac output measurements are often helpful in the management of critically ill patients and high risk-patients. In this study an alternative technique for measurement of cardiac output by the transpulmonary indicator dilution technique (TPID) was evaluated in comparison to conventional thermodilution using a pulmonary artery catheter. With TPID, a thermistor-tipped catheter (the smallest available is 1.3 F) is placed in the aorta via a femoral artery introducer. Thus, TPID can also be used in very small children in whom placement of a pulmonary artery catheter may be difficult or even impossible. In principle, TPID is less invasive since the possible complications of the pulmonary catheters are avoided. We investigated the accuracy and reproducibility of transpulmonary thermodilution in patients over a broad range in age and body surface. METHODS: Following approval by the ethics committee and written consent, the data were obtained from 21 patients without a circulatory shunt undergoing diagnostic heart catheterization. The patients were between 0.5 and 25.2 years old, their body surface between 0.35 and 1.89 m2. Measurements were performed in duplicate with bolus injections of ice-cold normal saline (0.15 ml/kg), randomly spread over the respiratory cycle. In total 48 thermodilution curves were measured simultaneously in the pulmonary artery and in the aorta. Thermodilution curves were monoexponentially extrapolated for elimination of recirculation and cardiac output was calculated with a standard Stewart Hamilton procedure. RESULTS: The amplitude of the typical arterial thermodilution curve shows a smaller and more delayed course than the pulmonary artery thermodilution curve. There was a very good correlation between the values found by pulmonary and TPID cardiac output measurements (R = 0.968). There was a slightly smaller cardiac output value measured by the TPID (Bias = -4.7 +/- 1.5% sem) The reproducibility of duplicate measurements with the two methods were nearly the same, the standard deviation of the difference was 10.9% for the pulmonary thermodilution method and 11.7% for TPID. DISCUSSION. TPID gives an alternative technique for measurement of cardiac output. We showed over a broad range in age and body surface a very good correlation with thermodilution measurements in the pulmonary artery. The slightly smaller values for TPID are explained by early recirculation, for clinical purposes the difference is negligible. However, the reproducibility of a method is clinically very important. Both methods showed in duplicate measurements basically the same reproducibility. The disadvantage of TPID in being more sensitive to baseline alteration is counterbalanced by less respiratory variability in comparison to the conventional thermodilution technique. However, by increasing the amount of injected indicator (i.e., 0.2 ml/kg approximately equal to 15 ml in an adult) it is possible to reduce the effect of baseline alteration. By using fiberoptic catheters it is even possible to use TPID as double-indicator dilution technique to measure intrathoracic blood volume (ITBV) and extravascular lung water (EVLW). We conclude that in many patients TPID might be an attractive, less invasive and reliable alternative to conventional cardiac output measurement by pulmonary artery catheter.
Adolescent↗
Influence of different types of recovery positions on perfusion indices of the forearm.
BACKGROUND: Basic life support guidelines of the European Resuscitation Council (ERC) suggest a modified type of recovery position compared to that recommended by the American Heart Association (AHA). However, anecdotal reports and the results of a small study by Fulstow and Smith (Resuscitation 1993; 26: 89-91) gave evidence that the new ERC position may cause an impairment of perfusion of the lower forearm. The aim of our study was to evaluate the effects of different recovery positions on arterial perfusion and venous drainage of the forearm. METHODS: We placed 20 young healthy volunteers randomly in either ERC or AHA position for 15 min first, and in the other position thereafter. Before and between volunteers were positioned supine. In a second series 10 volunteers were positioned according to the same protocol in semiprone positions as described by Morrison, Mirkhur and Craig (MMC), and Rautek's position, respectively. Forearm perfusion indices of the dependent arm were continuously assessed by photoplethysmographic pulsatility change, photoplethysmographic volume change, invasive peripheral venous pressure and non-invasive blood pressure amplitude. Subjective discomfort was assessed non-qualitatively. RESULTS: All indices of arterial perfusion demonstrated an impairment of arterial inflow in ERC, MMC and Rautek's position as well as venous congestion in these three positions. On the contrary, AHA position was associated with no significant changes of arterial flow and only moderate, insignificant signs of venous congestion. CONCLUSION: The results of this study suggest that AHA position causes less circulatory disturbances than the ERC, MMC and Rautek's positions.
Adult↗
[Double indicator methods for monitoring in the intensive care unit].
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Blood Volume↗
[The effect of an intracardiac left-right shunt on thermodilution measurements of cardiac output. An extracorporeal circulation model].
Thermodilution measurements of cardiac output (CO) by means of Swan-Ganz catheters, in a strict sense, represent pulmonary arterial blood flow (PBF). In principle, this is also true in the presence of intracardiac left-to-right shunts due to atrial or ventricular septal defects. However, early recirculation of indicator may give rise to serious methodological problems in these cases. We sought to determine the influence of intracardiac left-to-right shunts on different devices for thermodilution measurements of CO using an extra-corporeal flow model. METHODS. Blood flow was regulated by means of a centrifugal pump that at the same time enabled complete mixing of the indicator after injection (Fig. 1). Pulmonary and systemic parts of the circulation were simulated using two membrane oxygenators and a systemic-venous reservoir to delay systemic recirculation of indicator. Control measurements of PBF (Qp) and systemic (Qs) blood flow were performed by calibrated electromagnetic flow-meters (EMF). Blood temperature was kept constant using a heat exchanger without altering the indicator mass balance in the pulmonary circulation. Left-to-right shunt was varied at different systemic flow levels applying a Qp:Qs ratio ranging from 1:1 to 2.5:1. Thermodilution measurements of PBF were performed using two different thermodilution catheters that were connected to commercially available CO computers. Additionally, thermodilution curves were recorded on a microcomputer and analysed with custom-made software that enabled iterative regression analyses of the initial decay to determine that part of the downslope that best fits a mono-exponentially declining function. Extrapolation of the thermodilution curve was then based on the respective curve segment in order to eliminate indicator recirculation due to shunt flow. RESULTS. At moderate left-to-right shunts (Qp:Qs < 2:1) all thermodilution measurements showed close agreement with control measurements. At higher shunt flows (Qp:Qs > or = 2:1), however, conventional extrapolation procedures of CO computers considerably underestimated PBF (Fig. 2). This was particularly true when a slow-response thermistor catheter was used (Fig. 3). The reason for this underestimation of Qp was an overestimation of the area under curve because of inadequate mathematical elimination of indicator recirculation by standard truncation methods (Fig. 4). However, curve-alert messages of the commercially implemented software did not occur. A high level of agreement could be consistently obtained using a fast-response thermistor together with individual definition of extrapolation limits according to logarithmic regression analyses. DISCUSSION AND CONCLUSION. Under varying levels of left-to-right shunt, both the response time of thermodilution catheters and the algorithms for calculation of flow considerably influenced the validity of thermodilution measurements of PBF in an extracorporeal flow model. The use of computer-based regression analyses to define the optimal segment for monoexponential extrapolation could effectively eliminate indicator recirculation from the initial portion of the declining thermodilution curve and showed the closest agreement with EMF measurements of Qp. The quality of thermodilution curves with respect to recirculation peaks in the flow model was slightly better than in clinical routine. Nevertheless, the clinical applicability of the modified extrapolation algorithm could be illustrated during pulmonary thermodilution measurements in an exemplary patient with a ventricular septal defect (Fig. 5). PBF at extremely high shunt ratios, however, cannot be assessed by monoexponential extrapolation in principle (Fig. 6). Insufficient elimination of indicator recirculation resulted in flow values that closely resembled systemic rather than PBF. This finding is in accordance with a mathematical analysis of the underlying Steward-Hamilton equation if an infinite number of recirculations would be
Cardiac Output↗
Clinical value of aortic thermodilution monitoring of cardiac output in a small child after surgical correction of tetralogy of Fallot.
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Aorta, Thoracic↗
Clothing, assessment and effects on thermophysiological responses of man working in humid heat.
This paper presents the relative importance of the different factors to be taken into account when predicting thermal exchanges when man is wearing garments while being exposed to warm environments. Factors considered are the thermal insulation of clothing (CLO), the thermal efficiency of clothing (Fcl), the clothing area factor (fcl), the pumping coefficient (p), the vapour permeation efficiency factor (Fpcl). As Fpcl depends on CLO, Fcl,fcl and p factors, physiological assessments of this factor appears to be necessary for the calculation of the maximum evaporative capacity (Emax) in clothed subjects. In this paper, comparisons of body temperatures, whole body and local sweating were made from data obtained on both unclothed and then clothed subjects working at 50 watts on a cycloergometer in warm environments (Ta = Tr = Tsk), with increasing ambient humidity levels (Pa). Results showed that clothed subjects sweated more than unclothed man for the same Pa increases and hidromeiosis occurring on the skin of unclothed man seemed to be responsible for this. Sweat accumulation in the clothes confirms that the decrease in the evaporative sweat efficiency for clothed subjects was closely associated with the threshold for occurrence of core temperature drift. However the less important slope in the Tcore vs delta Pa relationship for clothed subjects compared to that for unclothed implies a more efficient body cooling thanks to clothing, which does not lead to as great a physiological disadvantage as expected. Pumping effect and additional concurrent evaporation could account for this phenomenon: the ISO model (Required sweat rate) which includes an additional air velocity as a function of metabolism allows us to consider this beneficial influence of increased Emax in clothed subjects. However this effect should not be considered when the model is used for unclothed subjects.
Adult↗
[Theoretical limits of "permissive anemia"].
The limiting factor for acute anemia is myocardial oxygen supply, since arterial oxygen content is decreased by isovolemic hemodilution while myocardial oxygen demand is increased as a result of a compensatory increase of cardiac output. A theoretical model was developed which describes the relation between hematocrit, myocardial oxygen demand and the required coronary blood flow during progressive hemodilution. Using this model, the determinants of critical hematocrit and the limits of intentional acute anemia (= "permissive anemia") can be calculated based on the limits of coronary vasodilator reserve. For a normal systemic oxygen consumption of 120 ml min-1 m-2 a critical degree of hemodilution is achieved at an hematocrit of 14% and an hemoglobin content of 4.7 g dl-1, respectively. Hyperoxia with an arterial pO2 of 400 mmHg will shift the critical hematocrit to 12%. An increase of systemic oxygen consumption by a factor of three (460 ml min-1 m-2), which might be typical for a patient during the postoperative recovery phase, increases the critical hematocrit to 21%. In patients with coronary artery disease critical hematocrit levels might be much higher. We conclude that a fixed critical hematocrit as a transfusion trigger is not appropriate in most patients. Rather the indication for blood transfusions must individually appreciate the specific circumstances of the patient, such as expected blood loss and required oxygen transport capacity reserves, hemodynamic stability, coronary artery disease and systemic oxygen consumption. It is suggested that the model presented herein might be valuable for estimation of the individual critical hematocrit in a particular patient.
Anesthesia Recovery Period↗
Humans under showers: thermal sensitivity, thermoneutral sensations, and comfort estimates.
Thirty male subjects participated in four experiments under showers to explore the sensitivities to water temperature and to its slow or rapid fluctuations. After having set the water temperature, at constant flow rate, at either a thermoneutral or a preferred level, subjects were asked to detect thermal changes or to report their thermosensory and affective judgments associated with water temperature changes. Results of water temperature, skin temperature, and subjective estimates showed that skin temperature for thermally neutral sensation under a shower were very similar to those observed in air, and such a thermoneutral level produced no discomfort. Preferred water temperature was slightly warmer and led to slightly elevated skin temperatures, warmth, and pleasantness estimates. Skin sensitivity to water thermal changes was very acute during slow and even more acute during rapid thermal transients. The conclusions of the present study are of value in the production of appropriate equipment to provide thermal comfort to people taking showers.
Adult↗
Application of a transpulmonary double indicator dilution method for postoperative assessment of cardiac index, pulmonary vascular resistance index, and extravascular lung water in children undergoing total cavo-pulmonary anastomosis: preliminary results in six patients.
Total cavo-pulmonary anastomosis (TCPA) is used for the functional correction of an increasing spectrum of congenital heart diseases. The passive pulmonary perfusion after surgical exclusion of the right ventricle has significant implications for the postoperative hemodynamic management of these patients. Because conventional pulmonary artery thermodilution catheters present methodologic problems in patients after TCPA, important cardiovascular variables such as cardiac index (CI) and pulmonary and systemic vascular resistance indices (PVRI, SVRI) usually cannot be assessed directly. In a preliminary series of six patients undergoing TCPA (age 6-22 years), the applicability of a transpulmonary double indicator dilution technique for postoperative determinations of CI, PVRI, SVRI, and extravascular lung water (EVLW) was investigated. After central venous injection of ice-cold indocyanine green (5 mg), thermal and dye dilution curves were recorded in the abdominal aorta using a combined 4F fiberoptic thermistor catheter. Qualitative assessment of the tracer curves did not show major differences in measurements in patients with pulsatile perfusion of the lungs. CI, SVRI, and EVLW could be determined by use of standard algorithms. Pulmonary perfusion pressure for the calculation of PVRI was based on the gradient between central venous and left atrial pressure. The quality of indicator dilution curves allowed determination of flow-related variables in 33 of a total of 34 sets of measurements. No catheter-related problems occurred during or after the period of investigation. Postoperative EVLW was within the range that is commonly accepted as normal for adults. Mean PVRI initially decreased during the postoperative course but showed a significant increase after extubation.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Bedside assessment of intravascular volume status in patients undergoing coronary bypass surgery.
BACKGROUND: Management of intravascular volume is crucial in patients after cardiopulmonary bypass as myocardial dysfunction is common. The purpose of this study was to validate a novel bedside technique for real-time assessment of intravascular volumes. METHODS: Eleven patients undergoing cardiopulmonary bypass were studied. In addition to standard monitors, a fiberoptic thermistor catheter was placed in the descending aorta and central venous injections of 10 ml ice-cold indocyanine green dye were performed. Total blood volume was measured by a standard in vitro technique. Circulating and central blood volume were calculated by using cardiac output, mean transit times, and a newly developed recursive convolution algorithm that models recirculation. Measurements were performed after induction of anesthesia and at 1, 6, and 24 h after surgery. RESULTS: A two-compartment model of the circulation was required for adequate fit of the data. We found a significant correlation between total and circulating blood volumes (r = 0.87). One hour after surgery, central blood volume was decreased by 10% (P < 0.05). At 6 and 24 h after surgery, circulating blood volumes were significantly increased by 29% and 20%, respectively (P < 0.01), although central blood volume was similar to control values. Before surgery stroke volume index correlated with circulating blood volume (r = 0.87) but not with pulmonary capillary wedge and central venous pressures. CONCLUSIONS: This study shows that bedside determinations of intravascular blood volumes are feasible and that these measurements are more indicative of intravascular volume status than are either pulmonary capillary wedge or central venous pressures in the post-cardiopulmonary bypass period. Our data also demonstrate that despite a normal central blood volume both circulating and total blood volume are significantly increased in the immediate post-cardiopulmonary bypass period.
Aged↗
The influence of anesthesia on myocardial oxygen utilization efficiency in patients undergoing coronary bypass surgery.
A maximum efficiency of myocardial oxygen utilization is desirable, especially in patients with limited coronary blood supply. Little is known about the effects of anesthesia on the efficiency of myocardial oxygen utilization. The aim of this retrospective study was to investigate the effects of different types of anesthesia on myocardial efficiency in patients undergoing coronary bypass surgery. Myocardial blood flow (Argon wash in technique), myocardial oxygen uptake, and standard hemodynamics were measured awake, after induction of anesthesia, and during sternal spread. Myocardial oxygen utilization efficiency was calculated from the ratio of external work divided by myocardial oxygen consumption. Sixty-five patients in eight groups with different anesthetic techniques were studied: 1) halothane/nitrous oxide, 2) enflurane/nitrous oxide, 3) high-dose morphine, 4) high-dose fentanyl, 5) fentanyl/midazolam, 6) high-dose sufentanil, 7) sufentanil/nitrous oxide, and 8) propofol. In all groups induction of anesthesia was associated with a decrease of cardiac work (from 86 +/- 17 to 55 +/- 16 J/min in pooled data) which resulted from a decrease of both stroke volume index and blood pressure. However, myocardial oxygen consumption did not decrease proportionally (from 11.2 +/- 3.0 to 8.5 +/- 2.3 mL.min-1 x 100 g-1 in pooled data) and myocardial oxygen utilization efficiency was therefore decreased in all groups (from 29.2% +/- 2.5% at awake state to 23.9% +/- 5.8% after induction of anesthesia in pooled data). Surgical stimulation by sternotomy and sternal spread was associated with different patterns of hemodynamic response between groups. Blood pressures and external work tended to be higher in the high-dose narcotic groups while it remained less affected in the other groups. However, myocardial efficiency remained depressed in all groups (22.2% +/- 8.2% in pooled data) and with respect to myocardial efficiency no differences between anesthetic techniques were found. We conclude that the specific anesthetic technique does not influence impairment of myocardial oxygen utilization efficiency by anesthesia.
Anesthesia↗