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M Georgieff

Publications and source records attributed to M Georgieff.

At least 181 records · Page 10Linked to original sources
PubMed1995

[Incidents, events and complications in the perioperative period in normal and malnurished patients--results of 23,056 patients].

AIM: Prevalence of cardiovascular risk factors in anaesthetic patients and perioperative pitfalls, events and complications (PECs) in different nutritional states were examined. The results should contribute to a current project of the German Society of Anaesthesiology and Intensive Care, established for quality assurance. METHOD: Preoperative data (age, sex, defined preexisting diseases, nutritional state, grade of urgency and ASA-class) were integrated in an automatically readable paper record, as well as the perioperative interventions and events, type of anaesthesia, and kind of operation. The records were routinely in use for every patient. After control and correction the data were stored in a modern data base. Data of patients under 16 years of age and incomplete sets of data were excluded from analysis. MAIN RESULTS: From July 1, 1992 to December 31, 1993 23,056 anaesthesias were recorded, 5,852 (25.4%) of them with a total of 8,107 PECs. 17,255 patients had normal body weight and 23% of them PECs. 4,484 obese (but not extremely) patients had a PEC rate of 31.2%, 330 extremely obese patients had a PEC rate of 38.2%, 966 patients with underweight (but not extremely) had a PEC rate of 36.1% and 21 with extreme underweight had a PEC rate of 38.1%. Obese patients had a higher prevalence of preexisting cardiovascular disturbances (angina pectoris, myocardial infarction and hypertension) and tended to a higher incidence of perioperative hypertensive, bronchospastic and hypoxic events as well as more difficulties in application of regional anaesthesia. Young adult patients (16-39 years) had a PEC rate of 14% in case of normal nutritional state but of 20% in case of obesity. The incidence of respiratory PECs and of PECs of higher severity was almost double in obese young patients compared to normal weight patients of the same age. When preoperative cardiovascular disease was known there was little difference between the different states of nutrition in respect of perioperative PECs. CONCLUSIONS: Nutritional disorder is an important epidemiological factor in anaesthesia. Particularly in younger patients without defined preoperative cardiovascular disturbance but with obesity the anaesthesist may be surprised by a remarkable incidence of relevant problems during and immediately after anaesthesia. We should consider the possible phenomenon that we are underestimating the anaesthetic challenge in young obese patients in a "healthy" cardiovascular state.

Adolescent↗
PubMed1995

[Clinical randomized controlled studies in anesthesiology according to the quality guidelines of good clinical practice. 1: Basic trial design].

This article was written to give researchers and clinicians a short synopsis of ethical and thorough design, conduct, analysis, publication, and interpretation of randomised controlled clinical trials according to the European quality standards of Good Clinical Practice (GCP). The paper consists of two parts. In the first part we introduce important elements of study design, especially study hypothesis, criteria of inclusion and study population, sample size calculation, validity considerations, bias and confounding, randomisation, stratification, and masking of treatment assignment. Different treatment allocation like multiple parallel groups, factorial experiment, cross-over, and sequential design are presented. Requirements of ethical standards according to the Declaration of Helsinki are discussed for their necessity in any experimentation in humans. Principles of informed consent are demonstrated with emphasis on special conditions in anaesthesia, emergency medicine, and intensive care research. In the second part of this article we explain issues of baseline assessment, experimental intervention, data recording, and data monitoring, particularly of negative or hazardous treatment effects. Topics of data analysis and reporting of trial results in publications are illustrated with regard to their influence on subsequent interpretation.

Anesthesiology↗
PubMed1995

[Clinical randomized controlled studies in anesthesiology according to quality guidelines of good clinical practice. 2: Principles of implementation, analysis, publication and evaluation].

This article was written to give researchers and clinicians a short synopsis of ethical and thorough design, conduct, analysis, publication, and interpretation of randomised controlled clinical trials according to the European quality standards of Good Clinical Practice (GCP). The paper consists of two parts. In the first part we introduce important elements of study design, especially study hypothesis, criteria of inclusion and study population, sample size calculation, validity considerations, bias and confounding, randomisation, stratification, and masking of treatment assignment. Different treatment allocation like multiple parallel groups, factorial experiment, cross-over, and sequential design are presented. Requirements of ethical standards according to the Declaration of Helsinki are discussed for their necessity in any experimentation in humans. Principles of informed consent are demonstrated with emphasis on special conditions in anaesthesia, emergency medicine, and intensive care research. In the second part of this article we explain issues of baseline assessment, experimental intervention, data recording, and data monitoring, particularly of negative or hazardous treatment effects. Topics of data analysis and reporting of trial results in publications are illustrated with regard to their influence on subsequent interpretation.

Anesthesiology↗
PubMed1995

[Intravenous anesthesia--current aspects].

Intravenous anaesthesia as a defined technique has become popular in recent years, since new developed drugs and more sophisticated application systems were introduced into clinical practice. However, only a minority of anaesthesiologists really practise this new technique. The scientific basis of continuous intravenous anaesthesia has not been spread widely in the anaesthetic community yet. The following review therefore focusses on recent findings and developments in the field of pharmacology, pharmacokinetics, pharmacodynamics and modern application systems of intravenous anaesthetic drugs. The new opioid remifentanil is described, new aspects in the interpretation of pharmacokinetic data are presented and the concept of context-sensitive halftimes as a parameter to estimate the decrease in clinical effect of intravenous anaesthetics is introduced. Drug effect in clinical anaesthesia is a result of equilibration of the drug with the effect site (Biophase). By means of defining the effect site equilibration time (t1/2ke0 and the drugs concentration at which this effect is achieved (Cp50) the pharmacodynamic properties of each intravenous anaesthetic can be characterised. Computerised pharmacokinetic data can be used to generate stable drug concentrations (target plasma concentration) when connected to an infusion pump. These target controlled systems are able to reach a predefined level rapidly and to maintain it. Thus pharmacodynamic interactions of intravenous drugs can be evaluated. The newly found properties of propofol, such as antiemetic, anticonvulsive and antioxidant, and its present clinical use are described. Finally, modern continuous intravenous anaesthetica techniques have been feasible only by the development of efficient application systems. The text gives an overview of the properties of modern syringe pumps and future developments of "smart" pumps.

Analgesics, Opioid↗
PubMed1995

Analgesic and hemodynamic effects of epidural clonidine, clonidine/morphine, and morphine after pancreatic surgery--a double-blind study.

This study characterizes analgesia an hemodynamics after epidural clonidine 8 micrograms/kg (Group C) or clonidine 4 micrograms/kg+morphine 2 mg (Group CM) in comparison to epidural morphine 50 micrograms/kg (Group M). Forty-five patients scheduled for pancreatectomy in combined general/epidural anesthesia were studied. The study drugs were administered 75 min postoperatively and for 10 h pain intensity (visual analog scale [VAS]), heart rate (HR), mean arterial pressure (MAP), and cardiac output (CO) were measured; filling pressures were kept > 5 mm Hg. Adequate analgesia could be achieved within 1 h in all patients of Groups C and CM, but only in six patients of Group M (P < 0.001). Quality of analgesia was comparable in all groups (VAS reduction 82% +/- 20%, mean +/- SD) but duration of analgesic action was longer in Groups CM (586 +/- 217 min) and M (775 +/- 378 min) compared to Group C (336 +/- 119 min) (P < 0.001). In Group M, no hemodynamic alterations occurred. In Groups C and CM, HR, CO, and MAP were reduced significantly compared to baseline within the first 15-90 min, while stroke volume and systemic vascular resistance remained stable. We conclude, that hemodynamic alteration after epidural clonidine under conditions of stable filling pressures is caused mainly by a decrease in HR. It is not an effect of analgesia but of the intrinsic antihypertensive action of clonidine.

Analgesia, Epidural↗
PubMed1995

Effect of 7.2% hypertonic saline/6% hetastarch on left ventricular contractility in anesthetized humans.

BACKGROUND: Although a positive inotropic effect of hypertonic saline has been demonstrated in isolated cardiac tissue as well as in animal preparations, no information exists about a possible positive inotropic action of hypertonic saline in humans. The aim of this investigation was to determine whether a clinically relevant positive inotropic effect can be demonstrated in humans. METHODS: Twenty-six patients without cardiovascular disease were randomized to receive 4 ml/kg of either 7.2% hypertonic saline/6% hetastarch or 6% hetastarch (control) at a rate of 1 ml.kg-1.min-1 while under general endotracheal anesthesia. Transesophageal echocardiography was used to evaluate left ventricular function. Arterial pressure, heart rate, and left ventricular end-systolic and end-diastolic diameter, area, and wall thickness were measured immediately before and after administration of either solution. Fractional area change, end-systolic wall stress, and the area under the end-systolic pressure-length relationship curve (ESPLRarea) were calculated. ESPLRarea was used to assess left ventricular contractility. RESULTS: Administration of hypertonic saline/hetastarch resulted in a significant decrease of mean arterial pressure and end-systolic wall stress from 77 +/- 14 (mean +/- SD) to 64 +/- 17 mmHg (P < 0.01) and from 52 +/- 14 to 32 +/- 11 10(3) dyne/cm2 (P > 0.01), respectively. End-diastolic area and fractional area change increased from 16.5 +/- 2.9 to 21.7 +/- 3.3 cm2 (P < 0.01) and from 0.53 +/- 0.07 to 0.70 +/- 0.06 (P < 0.01), respectively, whereas there was only a minor change of ESPLRarea from 38 +/- 13 to 44 +/- 13 mmHg.cm (P < 0.05). CONCLUSIONS: The apparent improvement of left ventricular systolic function in response to hypertonic saline/hetastarch is caused mainly by the combined effect of increased left ventricular preload and reduced left ventricular afterload. A possible positive inotropic action of hypertonic saline/hetastarch is not likely to be clinically relevant.

Adult↗
PubMed1995

Concentrations of prolactin and prostaglandins during and after cardiopulmonary resuscitation.

OBJECTIVES: To assess differences in plasma prolactin and prostaglandin concentrations in resuscitated and nonresuscitated patients during cardiopulmonary resuscitation (CPR), and to compare changes of prostaglandin and prolactin concentrations with hemodynamic variables in the immediate postresuscitation phase. DESIGN: Prospective, descriptive study. SETTING: Emergency medical service at a university hospital. PATIENTS: Twenty-nine patients ranging in age from 39 to 87 yrs with out-of-hospital cardiac arrest. INTERVENTIONS: Venous blood samples were taken during CPR and at 5, 15, 30, and 60 mins after restoration of spontaneous circulation in order to measure plasma concentrations of prolactin, prostaglandin F2 alpha, 15-keto-13,14-dihydro-prostaglandin F2 alpha, 6-keto-prostaglandin F1 alpha, and thromboxane B2 by immunoassay. Heart rate and blood pressure were measured at 5, 15, 30, and 60 mins after restoration of spontaneous circulation. MEASUREMENTS AND MAIN RESULTS: In 15 patients, restoration of spontaneous circulation was achieved; in the remaining 14 patients, successful resuscitation was not possible. During CPR, the mean plasma prolactin, prostaglandin F2 alpha, 15-keto-13,14-dihydro-prostaglandin F2 alpha, 6-keto-prostaglandin F1 alpha, and thromboxane B2 concentrations were 95.9 +/- 13.6 micrograms/L, 357 +/- 61 ng/L, 228 +/- 28 ng/L, 277 +/- 66 ng/L, and 375 +/- 78 ng/L, respectively, in resuscitated patients, and 23.9 +/- 5.6 micrograms/L (p = .0001), 192 +/- 22 ng/L (p = .005), 202 +/- 31 ng/L (p = .528), 221 +/- 40 ng/L (p = .713), and 344 +/- 77 ng/L (p = .780), respectively, in nonresuscitated patients. At 60 mins after restoration of spontaneous circulation, the mean plasma prolactin, prostaglandin F2 alpha, 15-keto-13,14-dihydro-prostaglandin F2 alpha, 6-keto-prostaglandin F1 alpha, and thromboxane B2 concentrations were 50.1 +/- 9.5 micrograms/L, 306 +/- 42 ng/L, 503 +/- 87 ng/L, 278 +/- 55 ng/L, and 355 +/- 30 ng/L, respectively. Mean values of systolic arterial blood pressure were 114 +/- 12 mm Hg at 30 mins and 123 +/- 18 mm Hg at 60 mins. No significant correlations were found between hemodynamic values and plasma concentrations of prolactin or prostaglandins. CONCLUSIONS: Prolactin and prostaglandin concentrations were increased during cardiac arrest and CPR. Successful initial resuscitation was associated with increased prolactin and prostaglandin F2 alpha concentrations during CPR. Decreased concentrations in non-resuscitated patients may have been a result of exhaustion of the neuroendocrine and eicosanoid systems, or may be due to differences in bioavailability at the site of blood sampling based upon differences in hemodynamics.

Adult↗
PubMed1995

Effects of PEEP ventilation on liver metabolism.

OBJECTIVE: To study the influence of positive endexpiratory pressure (PEEP) ventilation on metabolic parameters with specific regard to liver metabolism. DESIGN: Prospective experimental study on the effects of PEEP ventilation on hemodynamic and gas exchange as well as metabolic parameters, i.e. hepatic glucose production, arterial, hepatic and portal venous insulin, glucagon, free fatty acid (FFA), glycerol, beta-hydroxybutyrate and lactate concentrations. SETTING: Experimental Laboratory Unit of the University Hospital. ANIMALS: 10 Labrador Beagle dogs (18-22 kg) were studied. INTERVENTIONS: Animals were ventilated with PEEP of 0, 7.5, 15, and 0 mm Hg, each level lasting 2 h. RESULTS: PEEP 15 significantly increased heart rate from 110(70) to 220(55) beats/min and decreased cardiac output from 2.5 (2.0) to 1.5 (0.8) l/min. This was associated with significant increases in mean pulmonary artery pressure, pulmonary artery occlusion pressure, portal and hepatic venous pressure, whereas mean systemic pressure did not change. While whole-body oxygen consumption and respiratory quotient remained constant, whole-body oxygen delivery significantly decreased from 456(266) to 294(168) ml/min during PEEP 15 concomitant to augmented whole-body oxygen extraction (from 27(34) to 51(33)%). Oxygen extraction from the splanchnic organs increased from 41(31) to 81(30)%. Hepatic venous oxygen tension (PhvO2) and hemoglobin oxygen saturation (ShvO2) during PEEP 15 decreased from 41(18) to 28(47) mm Hg and from 60(31) to 18(66)%, respectively. Hepatic glucose production was significantly stimulated from 3.44(1.44) to 3.92(1.83) mg/kg/min at PEEP 15. Arterial and portalvenous glucagon/insulin ratios did not change. FFA and glycerol concentrations depending on PEEP levels were significantly higher in the hepatic artery and portal vein than in the hepatic vein. Compared to portal venous and arterial hepatic concentrations, hepatic venous beta-hydroxybutyrate significantly increased with rising PEEP levels. CONCLUSIONS: Low values of PhvO2 and ShvO2 during PEEP 15 gave evidence for hypoxia of the liver. This was associated with a stimulated hepatic glucose production rate accompanied by enhanced hepatic uptake and utilization of FFA serving as fuel substrates. As the rate of gluconeogenesis is a major determinant of hepatic oxygen consumption these metabolic effects of PEEP ventilation have to be considered during states of critical illness.

Animals↗
PubMed1994

Glucose and urea production and leucine, ketoisocaproate and alanine fluxes at supraphysiological plasma adrenaline concentrations in volunteers.

OBJECTIVE: To determine the magnitude and time course of adrenergic effects on metabolism in volunteers and possible implications for the use of sympathomimetics in the critically ill. DESIGN: Descriptive laboratory investigation. SUBJECTS: 7 volunteers. INTERVENTION: Primed continuous infusions of stable isotope tracers ([15N2]-urea, [6,6-D2]-glucose, [methyl-D3]-L-leucine, [15N]-L-alanine) were used. After isotopic steady state had been reached an infusion of adrenaline (0.1 microgram/kg/min) was administered (4 h). Isotopic enrichment was measured using gas chromatography-mass spectrometry and the corresponding rates of appearance were calculated. MEASUREMENTS AND MAIN RESULTS: Glucose production increased from 14.1 +/- 1.2 to 21.5 +/- 2.0 mumol/kg/min (p < 0.05) after 80 min of adrenergic stimulation and then decreased again to 17.9 +/- 1.2 mumol/kg/min after 240 min. Leucine and ketoisocaproate (KIC) fluxes were 2.3 +/- 0.2 and 2.6 +/- 0.2 mumol/kg/min, respectively, at baseline and gradually decreased to 1.8 +/- 0.2 and 2.2 +/- 0.1 mumol/kg/min, respectively, after 240 min of adrenaline infusion (both p < 0.05). Alanine flux increased from 3.7 +/- 0.5 to 6.9 +/- 0.9 mumol/kg/min (p < 0.05) after 80 min of adrenergic stimulation. Urea production slightly decreased from 4.8 +/- 0.9 to 4.3 +/- 0.8 mumol/kg/min during adrenaline (p < 0.05). CONCLUSIONS: Adrenaline induced an increase in glucose production lasting for longer than 240 min. The decrease in leucine and KIC flux suggests a reduction in proteolysis, which was supported by the decrease in urea production. The increase in alanine flux is therefore most likely due to an increase in de-novo synthesis. The ammonia donor for alanine synthesis in peripheral tissues and the target for ammonia after alanine deamination in the liver remain to be investigated. These results indicate that adrenaline infusion most probably will not promote already enhanced proteolysis in critically ill patients. Gluconeogenesis is an energy consuming process and an increase may deteriorate hepatic oxygen balance in patients.

Adult↗
PubMed1994

[The effect of theophylline on the mucociliary clearance function in ventilated intensive care patients].

Mucociliary clearance represents an important protective mechanism of the upper and lower respiratory tracts whereby inhaled particles and micro-organisms are removed from the tracheobronchial system. In incubated intensive care unit (ICU) patients, impaired ciliary function and mucus transport are associated with pulmonary complications [9]. Some authors have shown that theophylline increases mucus transport in healthy subjects and patients with chronic bronchitis [8, 16, 31, 36]. However, other investigators have found unconvincing or conflicting results [4, 20, 25]. Therefore, we studied the influence of theophylline on bronchial mucus transport velocity (BTV) in ventilated ICU patients. METHODS. The study was approved by the ethnics committee of our hospital. In a placebo-controlled double-blind study, the effect of therapeutic serum concentrations (10-20 micrograms/ml) of theophylline on BTV in ventilated patients in a surgical ICU was investigated. Group 1 (n = 10) served as controls and received placebo. The patients of group 2 (n = 10) were given intravenous infusions of 5 mg/kg body weight theophylline over 20 min, followed by 1 mg/kg per hour. Before administration of theophylline and 1 h after starting the infusion BTV, serum theophylline concentrations, and arterial blood gases were measured. Heart rate and blood pressure were registered every 5 min. In an additional study, the effect of theophylline on BTV at subtherapeutic serum concentrations (5 micrograms/ml) was investigated. BTV was measured with a small volume (0.05-0.08 ml) of albumin microspheres labeled with technetium-99m, which was deposited on the dorsal surface at the lower ends of the right and left main bronchi via a catheter placed in the inner channel of a fibre-optic bronchoscope. The movement of the microspheres towards the trachea was visualised and recorded using a scintillation camera [10]. RESULTS. The theophylline treatment induced a significant improvement in BTV from 3.8 to 7.6 mm/min in the left main bronchus and from 0.5 to 5.4 mm/min in the right, while placebo was inactive. The increase in BTV, however, was associated with an increase in heart rate; in 3 patients the theophylline infusion had to be stopped because of severe tachycardia. Blood gases and blood pressures did not change. Theophylline at subtherapeutic concentrations had no effect on either BTV or heart rate. CONCLUSIONS. Theophylline at therapeutic concentrations improves bronchial mucus transport in intubated ICU patients. The increase in BTV may be associated with severe tachycardia, and therefore routine application cannot be recommended.

Adolescent↗
PubMed1994

[The effect of thoracic epidural anesthesia on the pathophysiology of the eventration syndrome].

Abdominal mesenteric traction (MT) results in decreased mean arterial pressure (MAP), systemic vascular resistance (SVR) and increased cardiac output (CO). This response is induced by a considerable release of prostacyclin (PGI2). Precipitous falls in systemic arterial pressure related to central and/or autonomic nervous reflex arcs also have been described during operations on the upper abdominal viscera. Those hypotensive responses to visceral traction appear to be transmitted along afferent fibres contained within the splanchnic nerves. We investigated the influence of supplementary thoracic epidural anaesthesia on mesenteric traction response during major abdominal surgery. METHODS. With the approval of the Human Investigation Review Board we studied 40 patients scheduled for major abdominal surgery (infrarenal aortic, gastrointestinal and pancreatic surgery) according to a prospective, randomized double-blinded protocol. Patients were randomized to two different anaesthetic regimens. Patients in group 1 received general anaesthesia (GA n = 20) with 0.1-0.15 mg/kg midazolam and 10 micrograms/kg fentanyl prior to skin incision. Maintenance included 65% nitric oxide in oxygen and 0.1 mg increments of fentanyl as required. Group 2 patients (EA n = 20) underwent a combined technique of dose-reduced general anaesthesia and supplementary continuous, thoracic epidural anaesthesia (bupivacaine 0.25%, sensory blockade T4 to L1-3). In both anaesthesia groups ibuprofen (400 mg i.v.) or a placebo equivalent was administered 15 min before the induction of anaesthesia. MT was applied in a uniform fashion. Baseline values preceded the incision of the peritoneum. Further assessments followed 5, 15 and 30 min after MT. The plasma concentrations of 6-keto-PGF1 alpha (stable metabolite of PGI2), TXB2 (stable metabolite of thromboxane), PGF2 alpha, KH2-PGF2 alpha (stable metabolite of PGF2 alpha) were determined by radioimmunoassay. At all assessments we recorded systolic and diastolic blood pressure, heart rate and measured arterial blood gases. Statistical analyses were performed using three-factor ANOVA for repeated measurements after log(x) transformation. A P-value of less than 0.05 was considered significant when the Bonferroni-Holm adjustment was applied. RESULTS. Patients with supplementary epidural anaesthesia demonstrated lower systolic (P = 0.0001) and diastolic (P = 0.006) blood pressure than those in the GA group. Nevertheless, in untreated patients in the EA and GA group there was a significant decrease of about 20-30% in systolic and diastolic blood pressure (P = 0.0001) after mesenteric traction. Irrespective of the anaesthetic procedure, paO2 (P = 0.0001) decreased after mesenteric traction in the placebo group. The control patients in the GA group exhibited a more pronounced increase in heart rate after MT. After traction on the mesentery a significant 20- to 30-fold increase in 6-keto-PGF1 alpha plasma concentrations occurred in the placebo group: GA group 1950/58 (5 min), 1574/59 (15 min) 858/66 (30 min) ng/l, P < 0.0001; EA group: 2002/106 (5 min), 2955/107 (15 min) 1807/70 (30 min) ng/l, P < 0.0001, for placebo vs ibuprofen. There was no statistically significant difference between the two anaesthetic procedures used. In ibuprofen-pretreated patients haemodynamics and paO2 values were stable, while 6-keto-PGF1 alpha plasma concentrations remained within the normal range. CONCLUSION. Our data clearly indicate that the mesenteric traction response consists in relevant haemodynamic alterations and a significant decrease of paO2. Stable haemodynamics and paO2 following cyclooxygenase inhibition signify an action mediated by prostacyclin. Deafferentation of the splanchnic nerves by supplementary thoracic epidural anaesthesia did not influence either prostacyclin release or the decrease in blood pressure and paO2 after traction on the mesentery root...

Abdomen↗
PubMed1994

[The effect of changes in lung compliance on ventilation in newborns. Results of animal experiments with two different respirators].

In most ventilators used in anaesthesia tidal volume delivered during mechanical ventilation is different from the tidal volume preset at the respirator on the basis of respirator and circuit compliance and gas compression during inspiration. The error in ventilation due to the compressed volume is especially significant clinically when the tidal volume is very small or when the airway pressure is very high. In newborns and neonates in particular, decreasing lung compliance during a surgical procedure may contribute to marked hypoventilation. We therefore investigated ventilation in newborn piglets during decreasing lung compliance induced by tension pneumothorax. We used the anaesthesia ventilator CICERO (Dräger, Lübeck, Germany) and the SERVO 900 C ventilator (Siemens-Elema, Sweden). MATERIALS AND METHODS. Two anaesthesia ventilators, the CICERO (group I, n = 8) and the SERVO ventilators (group II, n = 8) were investigated following randomized selection in a group of 16 newborn piglets (Table 1). After normoventilation for 60 min a tension pneumothorax at +10 mbar was induced. After 15 min the pneumothorax was increased to +20 mbar and maintained at this level for the rest of the study. When hypercapnia (PaCO2 > 45 mmHg) resulted, the respiratory rate was increased by +10/min after 15 min with pneumothorax at +20 mbar. When hypercapnia continued, the respiratory rate was increased again 25 min and if necessary also 35 min after the induction of pneumothorax at +20 mbar. After normoventilation for 60 min (T1) (Table 2), after 15 min with pneumothorax at +10 mbar (T2) and after 15 min (T3), 25 min (T4), 35 min (T5) and 45 min (T6) with pneumothorax at +20 mbar the following parameters were obtained: central venous (CVP) and mean arterial pressure (MAP), heart rate (HR), arterial (PaCO2) and end-tidal CO2 tension (PetCO2), peak inspiratory pressure (PIP), respiratory frequency (RF) and expiratory tidal (Vtex) and minute volume (VE). RESULTS. In group I the pneumothorax resulted in a significantly smaller increase in PaCO2 (43.3 +/- 6.2 mmHg) than in group II (Fig. 1), and hypercapnia was present in only 3 piglets. Vtex (Fig. 2), VE (Fig. 3) and PIP (Fig. 5) increased significantly, with significantly higher values than in group II, while PetCO2 (Fig. 6) decreased significantly. In group II the pneumothorax was attributed to a significant increase in PaCO2 and a marked hypercapnia in all piglets (PaCO2 61.2 +/- 5.9 mmHg) (Fig. 1). Vtex (Fig. 2) and VE (Fig. 3) remained unchanged, while PIP (Fig. 5) and PetCO2 (Fig. 6) increased. Following the increase in RF (Fig. 4) in all piglets, Vtex and VE increased and PaCO2 and PetCO2 decreased. CONCLUSIONS. During ventilation of neonates with the SERVO ventilator a decrease in lung compliance will cause hypoventilation and hypercapnia. This reflected by an increase in peak inspiratory pressure and can be corrected by increasing the respiratory rate. In contrast, the CICERO is able to preserve ventilation by an internal correction for gas compression, but it does not guarantee normoventilation in all cases. In neither group does the end-tidal PCO2 reflect the true ventilation during decreasing lung compliance, so that arterial blood gas analysis seems to be mandatory for the diagnosis of hypercapnia in such situations.

Anesthesia↗
PubMed1994

[Perioperative endothelin, ACTH and cortisol plasma concentrations in coronary bypass patients].

STUDY OBJECTIVE: To follow up endothelin (ET), adrenocorticotropic hormone (ACTH), and cortisol levels in patients undergoing aortocoronary bypass grafting (CABG) and to determine whether these are extracted from plasma by the pulmonary circulation. DESIGN: Convenience sample trial. SETTING: University hospital. PATIENTS: Eight male routine CABG patients without appreciable concomitant disease. INTERVENTIONS: Patients were given anaesthesia in a strictly standardised manner using etomidate, flunitrazepam, fentanyl, and pancuronium. Nitroglycerin was administered prior to cardiopulmonary bypass (CPB) at 2 mg/h and dopamine as the only catecholamine starting from CPB weaning until the end of sampling at 3.5-5 micrograms/kg.min. Samples were drawn in rapid sequence from cannulated radial and a distal pulmonary arteries (Swan-Ganz catheter) at eight sampling times starting after induction of anaesthesia and catheter placement and finishing 22 h after the end of operation. MEASUREMENTS AND RESULTS: ET levels were determined by an ET-1, 2, 3-sensitive radioimmunoassay (RIA), ACTH and cortisol by commercially available RIA kits. There was significant (P = 0.032, linear regression analysis) correlation between ET and cortisol from pulmonary arterial samples. ET was significantly (P = 0.042, two-tailed Wilcoxon test) extracted by the pulmonary circulation after induction of anaesthesia. This pulmonary-systemic arterial difference nearly disappeared intraoperatively, but tended to be restored 22 h after the end of operation at an approximately twofold increased level. CONCLUSIONS: No interrelation between ET and the hypothalamic-pituitary-adrenal axis could be established by the ET, ACTH, and cortisol plasma levels. However, the significant correlation between perioperative ET and cortisol lends further support to the hypothesis of ET release by cortisol from vascular smooth-muscle cells. There is a net pulmonary clearance of ET in patients prior to CABG that is lost intra- and early postoperatively, but tends to be restored on the 1st day thereafter at an increased level.

Adrenocorticotropic Hormone↗
PubMed1994

Influence of intravenous calcium gluconate on saphenous vein graft flow in closed-chest patients.

The effects of calcium gluconate on hemodynamics and saphenous vein graft flow in a group of patients undergoing elective coronary artery bypass grafting who developed ionized hypocalcemia at the end of the surgical procedure were examined. The patients received a central venous bolus of 15 mg/kg of calcium gluconate. Heart rate (HR), arterial pressure (AP), central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and cardiac output were measured immediately before and 30, 60, 120, 180, and 240 seconds after injection of calcium gluconate. Systemic and pulmonary vascular resistance (SVR and PVR, respectively), cardiac index (CI), stroke volume index (SVI), and right and left ventricular stroke work index (RVSWI and LVSWI, respectively), were calculated. Venous bypass flow velocity (Vbypass-flow) was assessed using a Doppler probe that was attached to the left anterior descending artery (LAD) bypass intraoperatively. Calcium gluconate significantly increased MAP, SVR, and LVSWI from 67 +/- 3 mmHg (mean +/- SEM), 1,128 +/- 128 dyne.s.cm-5 and 25 +/- 3 g.m.beat/m to a maximum of 81 +/- 5 mmHg (P < 0.01), 1,401 +/- 196 dyne.s.cm-5 (P < 0.05), and 32 +/- 4 g.m/beat/m (P < 0.01), respectively. HR, CVP, PAP, PCWP, PVR, CI, SVI, and Vbypass-flow remained unaltered. It is concluded that calcium gluconate administered to moderately hypocalcemic patients increases arterial pressure mainly by peripheral vasoconstriction. Because the increase of arterial pressure, and, thereby, coronary perfusion pressure is not associated with an increase of LAD bypass flow, vasoconstriction in the coronary vascular bed distal to the venous graft cannot be ruled out, and deterioration of the myocardial oxygen supply/demand ratio is strongly suggested.

Aged↗
PubMed1994

[Abdominal complications following heart surgery].

OBJECTIVE: Intra-abdominal complications occurring after cardiopulmonary bypass operations are rare but often fatal. There are only speculative approaches concerning the pathogenesis and the risk factors of these complications. The aim of our study was therefore to determine the causative factors and to evaluate the diagnostic and therapeutic measures, because early diagnosis and immediate treatment is essential for the outcome of the patients. DESIGN: 500 consecutive patients who underwent cardiopulmonary bypass procedures over a period of 14 months were examined for intra-abdominal complications. The records of these patients were reviewed in relation to possible risk factors and the group with intra-abdominal complications was compared with a random sample of 50 patients in respect of possible risk factors. The diagnostic procedures (serum lactate concentrations, sigmoidoscopy, coloscopy) and the therapeutic interventions were also evaluated. MAIN RESULTS: 9 (1.8%) of the 500 patients developed intra-abdominal complications. The mortality rate was 44% (4 of 9). 5 patients had bowel necrosis or ischaemic colitis. Pseudo-obstruction appeared in 5 cases. One patient developed cholecystitis and one acute haemorrhagic pancreatitis. Gastroduodenal complications were not observed. There was no difference between the group with intra-abdominal complications and the random sample with regard to sex, type of operation and preoperative intra-abdominal diseases. Clinical risk factors identified were: age, occlusive vascular disease, atrial fibrillation, prolonged aortic cross-clamping times and mean bypass times, intraoperative and postoperative need for supply of epinephrine and norepinephrine, implantation of an intraaortic balloon counterpulsation pump, low cardiac output, postoperative multiple organ failure. 8 out of the 9 patients had severe intraoperative surgical complications or general complications in the postoperative course. All patients with bowel necrosis or ischaemic colitis had abnormal serum lactate concentrations. With the aid of sigmoidoscopy in one patient, only bowel necrosis or ischaemic colitis could be detected. In one patient with pseudoobstruction, an operation was probably obviated by decompression of the colon by coloscopy. 6 of the 500 patients after cardiopulmonary bypass required emergency laparotomy. Two patients with bowel necrosis were saved by early hemicolectomy. CONCLUSION: In reviewing both our results and data cited in earlier studies, intra-abdominal complications can generally be attributed to the following: Intraoperative surgical complications with the consequence of prolonged aortic cross clamping and total bypass times can cause low cardiac output and mesenteric hypoperfusion. Predominantly as a result of the low cardiac output, the use of vasopressors increases splanchnic ischaemia, in particular in patients with pre-existing occlusive vascular disease of the mesenteric arteries. Mucosal ischaemia might be aggravated by a concurrent pseudo-obstruction. On the other hand, intraoperative complications and low cardiac output can cause further complications and finally multiple organ failure. Multiple organ failure and ischaemia of the gut can initiate the vicious circle which is responsible for the high mortality from these complications. Early detection by careful physical examination and the combination of the diagnostic procedures and prompt treatment should lead to a reduction of mortality.

Abdomen↗
PubMed1994

[Analgesia and hemodynamics under 8 mu/kg clonidine for pain therapy following major abdominal surgery].

OBJECTIVE: To characterise the haemodynamic profile after epidural injection of high-dose clonidine for postoperative pain management and to establish recommendations for the therapy of haemodynamic instabilities. DESIGN: 20 patients with major surgery on pancreas, stomach or infrarenal aorta took part in the study. Anaesthesia was a combined epidural/inhalational regimen with bupivacaine 0.25%, enflurane, oxygen/nitrous oxide, fentanyl 0.1 mg and pancuronium. Postoperative analgesia consisted of morphine 50 micrograms/kg in 10 ml NaCl 0.9% for the first 12 postoperative hours; if pain > = 5 points on the VAS occurred after > 12 h postoperatively clonidine 8 micrograms/kg in 10 ml NaCl 0.9% was injected epidurally and the pain intensity (self-assessment by the patient using the visual analog scale) and circulation (invasive pressure monitoring, pulmonary artery catheter) was monitored for 60 minutes in ten minutes intervals. RESULTS: The reduction of the initial VAS score of 6 was 50% after 20 minutes and 100% after 60 minutes. We observed a significant decline in heart rate (87 +/- 11 (t0), 74 +/- 10 min-1 (t60)), mean arterial pressure (97 +/- 17 (t0), 72 +/- 15 mmHg (t60)) and cardiac output (8.7 +/- 1.3 (t0), 7.0 +/- 1.3 l.min-1 (t60)) (all p < 0.001) and no change of systemic vascular resistance. Filling pressures (CVP and PCWP) remained stable. In 9 patients the mean arterial pressure fell below 60 mmHg (always within the first 40 min); 6 of these patients responded to infusion of a colloid (500 ml of hydroxyethyl starch at > = 2 ml/kg.min) whereas the other 3 patients needed a bolus injection of a betamimetic catecholamine (theodrenaline/cafedrine, Akrinor). CONCLUSION: Epidural clonidine 8 micrograms/kg causes rapid and intense analgesia. Haemodynamic instability is a consequence of a drop in heart rate and has to be treated accordingly. The application of a pure vasopressor does not seem to be indicated taking in account the fact that the total peripheral resistance remains unchanged and in the normal range.

Abdomen↗