Biomedical subjects

M Georgieff

Publications and source records attributed to M Georgieff.

At least 91 records · Page 5Linked to original sources

PubMed1999

Xenon does not trigger malignant hyperthermia in susceptible swine.

BACKGROUND: Xenon is a noble gas with anesthetic properties currently under investigation for use in humans. This study was performed to evaluate whether xenon may trigger malignant hyperthermia in susceptible swine. METHODS: Nine malignant hyperthermia-sensitive swine (Pietrain) were initially anesthetized with pentobarbital and then ventilated with 70% xenon in oxygen for 2 h. Heart rate, mean arterial pressure, cardiac output, body temperature, arterial and mixed-venous blood gases, and plasma catecholamine and lactate levels were measured every 10 min both during xenon-oxygen ventilation and after a 30-min xenon washout phase followed by subsequent administration of halothane (1% inspired) and succinylcholine (3 mg/kg intravenous). During the investigation, no malignant hyperthermia-specific therapy was instituted. RESULTS: Xenon exposure did not induce any changes in metabolic and hemodynamic parameters nor elevations of the plasma catecholamine levels indicative for an episode of malignant hyperthermia. By contrast, in all animals, within 20 min after the administration of halothane and succinylcholine, fulminant and fatal malignant hyperthermia episodes were initiated. CONCLUSIONS: The authors conclude that xenon does not trigger malignant hyperthermia in susceptible swine.

Amino Acid Substitution↗

PubMed1999

Respiratory mechanics during xenon anesthesia in pigs: comparison with nitrous oxide.

BACKGROUND: Because of its high density and viscosity, xenon (Xe) may influence respiratory mechanics when used as an inhaled anesthetic. Therefore the authors studied respiratory mechanics during xenon and nitrous oxide (N2O) anesthesia before and during methacholine-induced bronchoconstriction. METHODS: Sixteen pentobarbital-anesthetized pigs initially were ventilated with 70% nitrogen-oxygen. Then they were randomly assigned to a test period of ventilation with either 70% xenon-oxygen or 70% N2O-oxygen (n = 8 for each group). Nitrogen-oxygen ventilation was then resumed. Tidal volume and inspiratory flow rate were set equally throughout the study. During each condition the authors measured peak and mean airway pressure (Pmax and Pmean) and airway resistance (R(aw)) by the end-inspiratory occlusion technique. This sequence was then repeated during a methacholine infusion. RESULTS: Both before and during methacholine airway resistance was significantly higher with xenon-oxygen (4.0 +/- 1.7 and 10.9 +/- 3.8 cm H2O x s(-1) x 1(-1), mean +/- SD) when compared to nitrogen-oxygen (2.6 +/- 1.1 and 5.8 +/- 1.4 cm H2O x s(-1) x l(-1), P < 0.01) and N2O-oxygen (2.9 +/- 0.8 and 7.0 +/- 1.9, P < 0.01). Pmax and Pmean did not differ before bronchoconstriction, regardless of the inspired gas mixture. During bronchoconstriction Pmax and Pmean both were significantly higher with xenon-oxygen (Pmax, 33.1 +/- 5.5 and Pmean, 11.9 +/- 1.6 cm H2O) when compared to N2O-oxygen (28.4 +/- 5.7 and 9.5 +/- 1.6 cm H2O, P < 0.01) and nitrogen-oxygen (28.0 +/- 4.4 and 10.6 +/- 1.3 cm H2O, P < 0.01). CONCLUSIONS: Airway pressure and resistance are increased during xenon anesthesia. This response is moderate and not likely to assume major importance for the general use of xenon in anesthesia.

Algorithms↗

PubMed1999

Effect of dobutamine on splanchnic carbohydrate metabolism and amino acid balance after cardiac surgery.

BACKGROUND: As a predominant beta-adrenergic agonist, dobutamine may modify blood flow distribution and increase metabolic demands. The authors investigated the effect of a dobutamine-induced increase in cardiac output on splanchnic and femoral blood flow and metabolism in patients after cardiac surgery. METHODS: Seventeen stable patients were randomized to receive dobutamine or placebo (n = 8 per group, one dropout). After baseline measurement for systemic, splanchnic, and femoral blood flow (by dye dilution); oxygen consumption; gastric mucosal pressure of carbon dioxide (Pco2); total and splanchnic glucose production (by stable isotope tracer dilution); and regional lactate and amino acid balance, patients received either dobutamine, at a dosage (6 microg x kg(-1)min(-1)) sufficient to increase cardiac index by at least 25%, or placebo. A second set of measurements was performed 60 min after the start of dobutamine or placebo infusion. RESULTS: Dobutamine increased cardiac index (3.0+/-0.6 to 4.4+/-1.0 l x min(-1)m(-2), mean +/- SD; P < 0.05), splanchnic blood flow (from 0.8+/-0.2 to 1.0 + 0.2 l x min(-1)m(-2); P < 0.05), femoral blood flow (from 0.2+/-0.1 to 0.3+/-0.1 l x min(-1)m(-2); P < 0.05), and the arterial-gastric mucosal Pco2 gap (from 11.4+/-9.5 to 11.9+/-8.0 mmHg; P < 0.05). Dobutamine increased systemic oxygen consumption (from 132+/-14 to 146+/-13 ml x min(-1) x m(-2); P < 0.05) but not splanchnic or femoral oxygen consumption. Splanchnic glucose production and lactate and amino acid balance did not change. CONCLUSION: After coronary artery bypass surgery, dobutamine increased systemic and regional blood flow and decreased systemic and regional oxygen extraction. Dobutamine did not affect splanchnic glucose production or lactate or amino acid balance. This suggests that dobutamine increases splanchnic blood flow without a concomitant increase in hepatosplanchnic metabolism.

Adrenergic beta-Agonists↗

PubMed1999

Impact of exogenous beta-adrenergic receptor stimulation on hepatosplanchnic oxygen kinetics and metabolic activity in septic shock.

OBJECTIVE: To investigate the impact of exogenous beta-adrenergic receptor stimulation on splanchnic blood flow, oxygen kinetics, glucose-precursor flux, and liver metabolism in septic shock. DESIGN: Prospective trial. SETTING: University hospital intensive care unit. PATIENTS: Six patients with hyperdynamic (cardiac index >4.0 L/min/m2) septic shock, all requiring norepinephrine to maintain blood pressure >65 mm Hg. INTERVENTIONS: We compared norepinephrine and phenylephrine titrated to achieve similar systemic hemodynamics and gas exchange. Splanchnic hemodynamics, oxygen kinetics, and metabolic parameters were measured before, during, and after replacing norepinephrine with phenylephrine. MEASUREMENTS AND MAIN RESULTS: Splanchnic blood flow and oxygen kinetics were derived from the steady-state indocyanine-green clearance based on hepatic dye extraction and arterial and hepatic venous blood gases. Endogenous glucose production rate was derived from the plasma appearance rate of stable-isotope-labeled glucose using a primed-constant infusion. Splanchnic lactate, alanine (high-performance liquid chromatography) uptake, and hepatic monoethylglycinexylidide (MEGX) (fluorescence polarization immunoassay) formation rates were calculated from splanchnic blood flow and arterial-hepatic venous concentration differences. Replacing norepinephrine with phenylephrine induced no change in systemic hemodynamics or gas exchange. While splanchnic oxygen consumption and alanine uptake rate remained unaffected, splanchnic blood flow, oxygen delivery, and lactate uptake rate were significantly decreased. Glucose production rate also decreased significantly. A return to norepinephrine restored splanchnic blood flow, oxygen delivery, and lactate uptake rate to baseline values, while glucose production rate remained depressed. Hepatic MEGX formation rate was not influenced during the investigation. CONCLUSIONS: Exogenous beta-adrenergic receptor stimulation determines splanchnic blood flow, oxygen delivery, and glucose precursor flux but not splanchnic oxygen utilization in septic shock. Gluconeogenesis is not directly affiliated to hepatosplanchnic oxygen kinetics. The different response of glucose and MEGX production rates, metabolic pathways of the periportal and perivenous region, may document intrahepatic heterogeneity associated with hepatocellular metabolic compartmentation.

Aged↗

PubMed1999

Changes in gastric intramucosal pH following mesenteric traction in patients undergoing pancreas surgery.

BACKGROUND/AIM: During major abdominal surgery, mesenteric traction (MT) may result in hemodynamic instability mainly due to endogenous prostacyclin release. Gastric intramucosal pH (pHi) and PiCO2 are indicators of splanchnic tissue perfusion with a predictive value for the postoperative outcome. We investigated the influence of MT on gastric pHi and on postoperative outcome in patients undergoing pancreas surgery. METHODS: Forty-six consecutive patients scheduled for pancreas surgery were investigated. We registered hemodynamics and pHi by gastric tonometry and documented postoperative outcome (complications, hospital stay). Baseline data (T0) were recorded after skin incision. Further assessments followed 30, 60 and 120 min after intentional MT (T1-3) and at the end of surgery (T4). RESULTS: Thirty-three patients demonstrated a decrease in mean arterial pressure (MAP) following MT, whereas 13 patients showed entirely stable hemodynamics. The significant reduction in MAP in patients with an MT response was not associated with changes in pHi as compared to patients with no response (stable MAP) (T0 7.34 +/- 0.08 vs. 7.35 +/- 0.06; T1 7.34 +/- 0.05 vs. 7.32 +/- 0.07; T2 7.32 +/- 0. 05 vs. 7.31 +/- 0.08; T3 7.32 +/- 0.05 vs. 7.32 +/- 0.07; T4 7.26 +/- 0.1 vs. 7.27 +/- 0.08; mean +/- SD, MT response vs. no response). Neither MT response nor gastric intramucosal acidosis as evidenced by a pHi <7.32 at the end of surgery predicted postoperative complications or longer hospital stay. CONCLUSION: No deterioration of gastric pHi was found, which could reflect acceptable splanchnic perfusion and oxygenation despite systemic blood pressure reactions in patients experiencing an MT response.

Adult↗

PubMed1999

Norepinephrine and nomega-monomethyl-L-arginine in porcine septic shock: effects on hepatic O2 exchange and energy balance.

We compared the effects of norepinephrine (NOR; n = 11) and the nonselective nitric oxide synthase inhibitor Nomega-monomethyl-L-arginine (L-NMMA; n = 11) on hepatic blood flow (Q liv), O2 exchange, and energy metabolism over 24 h of hyperdynamic, normotensive porcine endotoxic shock. Endotoxin (ETX; n = 8) caused a continuous fall in mean arterial pressure (MAP) despite a sustained 50% increase in cardiac output (Q) achieved by adequate fluid resuscitation. NOR maintained MAP at preshock levels owing to a further rise in Q, while the comparable hemodynamic stabilization during L-NMMA infusion resulted from systemic vasoconstriction, increasing the systemic vascular resistance (SVR) about 30% from shock level after 6 h of treatment concomitant with a reduction in Q to preshock values. Whereas NOR also increased Q liv and, hence, hepatic O2 delivery (hDO2), but did not affect hepatic O2 uptake (hVO2), L-NMMA influenced neither Q liv nor hDO2 and hVO2. Mean capillary hemoglobin O2 saturation (HbScO2) on the liver surface as well as HbScO2 frequency distributions, which mirror microcirculatory O2 availability, remained unchanged as well. Neither treatment influenced the ETX-induced derangements of cellular energy metabolism reflected by the progressive decrease in hepatic lactate uptake rate and increased hepatic venous lactate/pyruvate ratios. ETX nearly doubled the endogenous glucose production (EGP) rate, which was further increased with NOR, whereas L-NMMA nearly restored EGP to preshock levels. Nevertheless, despite the different mechanisms in maintaining blood pressure neither treatment influenced ETX-induced liver dysfunction.

Animals↗

PubMed1999

The performance of electroencephalogram bispectral index and auditory evoked potential index to predict loss of consciousness during propofol infusion.

UNLABELLED: The bispectral index (BIS) of the electroencephalogram and middle latency auditory evoked potentials are likely candidates to measure the level of unconsciousness and, thus, may improve the early recovery profile. We prospectively investigated the predictive performance of both measures to distinguish between the conscious and unconscious state. Twelve patients undergoing lower limb orthopedic surgery during regional anesthesia additionally received propofol by target-controlled infusion for sedation. The electroencephalogram BIS and the auditory evoked potential index (AEPi), a mathematical derivative of the morphology of the auditory evoked potential waveform, were recorded simultaneously in all patients during repeated transitions from consciousness to unconsciousness. Logistic regression procedures, receiver operating characteristic analysis, and sensitivity and specificity were used to compare predictive ability of both indices. In the logistic regression models, both the BIS and AEPi were significant predictors of unconsciousness (P < 0.0001). The area under the receiver operating characteristic curve for discrete descending index threshold values was apparently, but not significantly (P > 0.05), larger for the AEPi (0.968) than for the BIS (0.922), indicating a trend of better discriminatory performance. We conclude that both the BIS and AEPi are reliable means for monitoring the level of unconsciousness during propofol infusion. However, AEPi proved to offer more discriminatory power in the individual patient. IMPLICATIONS: Both the bispectral index of the electroencephalogram and the auditory evoked potentials index are good predictors of the level of sedation and unconsciousness during propofol infusion. However, the auditory evoked potentials index offers better discriminatory power in describing the transition from the conscious to the unconscious state in the individual patient.

Aged↗

PubMed1999

[Effects of priming technique on onset profile of cisatracurium].

Compared to atracurium, cisatracurium releases less laudanosine and histamine, but it has a longer onset time. The primary objective of this study was a blinded, randomized comparison of intubation scores and onset times of a threefold ED 95 of cisatracurium using the priming technique with two priming substances cisatracurium itself and pancuronium. To test the effect of priming with cisatracurium or pancuronium on the onset of cisatracurium, 45 patients were anaesthetised with 0.15-0.25 mg/kg alfentanil, 0.25-0.3 mg/kg edomidate i.v. and O2/N2O, and were randomisely divided into one of three groups. After induction, 15 patients were primed with sodium chloride and thereafter received 0.15 mg/kg cisatracurium, 15 patients were primed with 0.01 mg/kg cisatracurium, another 15 patients were primed with 0.015 mg/kg pancuronium and the last two groups received 0.14 mg/kg cisatracurium three minutes later. Neuromuscular response was monitored by adductor pollicis electromyogram (EMG) by stimulating in a TOF pattern. Times for T1 reduction to 75%, 50%, 25% and 0% and T1 recovery to 25% were taken. Intubation was performed 120 seconds after the main relaxant dose and scored in four grades. The two priming groups showed a significantly faster onset of neuromuscular blockade than the control group (cisatracurium priming group: T1 = 0: 178.4 +/- 16.3 sec., pancuronium priming group 171.2 +/- 15.3 sec. vs. control group: T1 = 0: 205.5 +/- 18.9 sec.). Both primed groups showed no significantly better intubation scores, compared with the control group. Using the priming principle, cisatracurium will give good intubation scores 120 seconds after injection with a clinical duration profile comparable to an equipotent dose of atracurium.

Adult↗

PubMed1998

Ibuprofen does not impair renal function in patients undergoing infrarenal aortic surgery with epidural anaesthesia.

OBJECTIVE: To investigate the effect of preoperative ibuprofen administration on renal function during and after infrarenal aortic surgery under thoracolumbar epidural anaesthesia (EPA). DESIGN: A prospective randomised, double-blinded clinical study. SETTING: Operation room and intensive care unit in a university hospital. PATIENTS: Twenty-six consecutive patients scheduled for elective infrarenal aortic surgery. INTERVENTIONS: The patients were prospectively randomised to receive 400 mg ibuprofen intravenously (i.v.) or a placebo aliquot before surgery. MEASUREMENTS AND RESULTS: We assessed renal function by calculating creatinine clearance, and fractional sodium excretion before surgery (baseline), 1 h after cross-clamping (intraoperative), 6 h after cross-clamping (postoperative) and 24 h after cross-clamping (on the 1 st postoperative day). At each point in time, we additionally registered haemodynamics and determined the plasma concentration of 6-keto-PGF1alpha (stable metabolite of prostacyclin, PGI2), bicyclic PGE2 (stable metabolite of PGE1 E2), active renin, aldosterone and vasopressin by radioimmunoassays. Throughout the observation period the renal function parameters mostly remained within the normal range without a significant difference between ibuprofen- and placebo-treated patients (creatinine clearance: baseline 41 +/- 3 vs 38 +/- 6, intraoperative 57 +/- 8 vs 64 +/- 11, postoperative 64 +/- 9 vs 56 +/- 9, first postoperative day 43 +/- 5 vs 47 +/- 6 ml x min x m(-2), means +/- SEM). The plasma levels of 6-keto-PGF1alpha (68 +/- 8 vs 380 +/- 71* ng x l(-1)), bicyclic PGE2 (57 +/- 5 vs 88 +/- 9* ng x l(-1)) and vasopressin (14 +/- 7 vs 45 +/- 10* ng x l(-1), p < 0.0125), however, were significantly higher during the intraoperative period in the placebo-treated patients. CONCLUSION: The inhibition of endogenous prostaglandin release by ibuprofen does not substantially impair renal function during infrarenal aortic surgery under EPA.

Aged↗

PubMed1998

Work of breathing, inspiratory flow response, and expiratory resistance during continuous positive airway pressure with the ventilators EVITA-2, EVITA-4 and SV 300.

OBJECTIVE: To analyze work of breathing (WOB) imposed by the respirators EVITA-2, EVITA-4 (Drägerwerk, Lübeck, Germany) and SV 300 (Siemens-Elema, Sweden) as well as inspiratory flow response and expiratory flow resistance during continuous positive airway pressure (CPAP). DESIGN: Five study conditions on a lung model (CPAP at 0, 5, and 10 mbar, CPAP 5 mbar plus pressure support 2 mbar with both EVITA models, and CPAP 5 mbar with decreasing levels of flow and pressure trigger sensitivity with the SV 300) and three randomized study conditions in nine patients recovering from open heart surgery (condition A: EVITA-2, CPAP 5 mbar; condition B: SV 300, CPAP 5 mbar, flow trigger; condition C: SV 300, pressure trigger-4 mbar). SETTING: University hospital intensive care unit and laboratory of pulmonary physiology. MEASUREMENTS AND RESULTS: At each study condition we measured WOB, pressure-time product (PTP), WOB and PTP imposed (WOBimposed and PTPimposed), tidal volume, minute ventilation, respiratory rate, inspiratory trigger time, trigger pressure, trigger PTP, duration of inspiration, mean and peak inspiratory flow, and the delay from the onset of inspiration to peak inspiratory flow. Since the SV 300 automatically generates an additional pressure support of 2 cm H2O PTP, WOB, WOBimposed, and PTPimposed were higher with the EVITA-2 and EVITA-4 regardless of the trigger sensitivity set on the SV 300. The difference was neutralized with both types of EVITA ventilator by adding 2 mbar of pressure support during CPAP in order to achieve comparable conditions. Inspiratory flow response was faster with both EVITA models, expiratory flow resistance was higher with the SV 300. Decrements of trigger sensitivity with the SV 300 accelerated the flow response. CONCLUSIONS: Under similar conditions, no difference in WOBimposed was observed, although inspiratory flow response and expiratory flow resistance differed substantially between the three ventilators tested. Trigger sensitivity plays a minor role in determining PTP and WOB but has major influence on flow.

Aged↗

PubMed1998

Cardiac function in patients with treated hypertension during aortic aneurysm repair.

OBJECTIVES: To investigate the impact of arterial hypertension on cardiac function during aortic cross-clamping and declamping. DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Twenty treated hypertensive males with slight left ventricular hypertrophy and 10 normotensive controls undergoing elective repair of an abdominal aortic aneurysm. INTERVENTIONS: Using transesophageal echocardiography, the mitral inflow profile was evaluated during aortic cross-clamping and declamping. MEASUREMENTS AND MAIN RESULTS: During the clamping period, the ratio of peak atrial to peak early filling velocity (PA/PE) was significantly higher in the hypertensive patients. One minute after aortic cross-clamping, mean arterial pressure (MAP) and pulmonary artery occlusion pressure significantly increased in the hypertensive patients, whereas they did not change in the normotensive group. Cardiac index and heart rate significantly decreased after cross-clamping, and increased after clamp release in both groups. PA/PE significantly dropped in both groups after aortic declamping, and returned to baseline values thereafter. MAP also decreased significantly in both groups after clamp release, but the fall of MAP tended to be more pronounced in the hypertensive patients. CONCLUSIONS: In the treated hypertensive patients, more pronounced hemodynamic and echocardiographic responses to aortic cross-clamping probably mirror the altered diastolic left ventricular function in these patients. With respect to intraoperative management, however, the treated hypertensive patients did not react grossly differently from the normotensive controls.

Aged↗

PubMed1998

A novel apparatus for the exposure of cultured cells to volatile agents.

This article presents a novel exposure apparatus that allows the exposure of cultured cells to volatile chemicals, e.g., inhalation anesthetics. The apparatus consists of an exposure chamber and a tightly linked vaporizer unit with pumps and valves allowing adjustable fluxes of mixtures of test chemicals and carrier gas under open and closed-circuit conditions. The exposure chamber uses commercially available cell culture flasks and accommodates up to 12 flasks simultaneously. Both modules fit into a standard culture incubator. The exposure chamber may be mounted onto an oscillating axis to tilt the cultures periodically forth and back, thus allowing direct contact of the cells with test atmosphere. The vaporizer unit is connected to a personal computer which lets the experimenter set the "open" and "close" intervals of individual valves thereby controlling the composition and flow rate of the test gas mixture. The vapor concentration of test chemicals can be monitored at the inlet and outlet using infrared photodetectors or mass spectrometers. Computer-aided processing of exposure protocols allows unattended runs. Exposure protocols can be scripted and stored on disk, thus ensuring interexperimental reproducibility of complex exposure profiles. As an application example, the effect of three volatile anesthetics, halothane, enflurane, and isoflurane, on the viability of three commercially available cell lines (A549--human lung carcinoma, HTC-rat hepatoma, MDCK--Madin-Darby canine kidney) was investigated. After exposure to haloalkyl vapors (3%) for 6 and 24 h, respectively, significantly increased LDH levels versus controls, indicating cellular membrane damage, were detected in A549 and hepatoma cells after exposure for 24 h. Hepatoma cells showed a significant LDH release also after 6 h exposure to isoflurane. On the other hand, LDH release from MDCK cells was not significantly different from controls even after 24 h of continuous exposure to any of the tested anesthetics.

Anesthetics, Inhalation↗

PubMed1998

A cross-validated multifactorial index of perioperative risks in adults undergoing anaesthesia for non-cardiac surgery. Analysis of perioperative events in 26907 anaesthetic procedures.

OBJECTIVE: To develop a severity index of anaesthetic risk that predicts relevant perioperative adverse events in adults. DESIGN: Prospective cross-sectional study. SETTING: Department of anaesthesiology at one university hospital. PATIENTS: 26907 consecutive anaesthetic procedures in patients over 15 years of age and a complete preoperative evaluation. Patients undergoing cardiac and obstetric surgery were excluded. MEASUREMENTS AND MAIN RESULTS: Demographic data, preoperative health status, type of anaesthesia, operative procedures, and perioperative incidents (standardised on a national basis) were acquired by means of a computerised anaesthetic record system. Occurrence of at least one perioperative event with impact on postanaesthetic care was computed by a multivariate logistic regression model against 17 variables with different characteristics representing possible risk factors. Fourteen variables proved to be independent risk factors. The weighting of the variables was expressed in scores which added up to form a simple index for each patient. Patients without major risk factors (0-10 points) had a 0.3% risk of suffering from a relevant incident. Patients with more than 60 points had a 28.6% risk. The results were well demonstrated by cross-validation. CONCLUSIONS: The index seems to reflect the risk of relevant perioperative incidents. It can be used for audit purposes. In daily routine, the index could focus our attention on patients with increased perioperative risk. However, it is limited in detecting particular constellations of factors which interact on each other with regard to perioperative risk.

Adolescent↗

PubMed1998

Validation of routine incidence reporting of one anaesthesia provider institution within a nation-wide quality of process assessment program.

In 1992, a long-term project was launched by the German Society for Anaesthesiology and Intensive Care Medicine to render quality comparisons between anaesthesia providers. As one of the first volunteer centres, we established the standardised reporting of perioperative anaesthesia related incidents, events, and complications (IEC) in any routine anaesthetic procedure performed. This present study is aimed to explore the longitudinal stability of IEC recordings in one institution, which should be a prerequisite for valid external comparisons. Methods. The analyses were completed on an adult population of 49945 consecutive anaesthetic procedures with peripheral surgery from July 1992 until December 1996. Attribute quality control charts with monthly samples of an average of 954 anaesthetics were used to assess statistical variability of specific IEC incidences. Results. Average proportions were 20% for moderate IEC, 2.7% for severe IEC, 13% for moderate cardio-vascular IEC, 1.3% for severe cardio-vascular IEC, and 2.4% for respiratory IEC. Moderate IEC proportions showed considerable variability during the study period. A series of excess proportions was probably due to educational activities on documentation discipline. In contrast, clinically severe IEC proportions were rather stable. Stability of cardio-vascular IEC proportions resembled the picture of the overall IEC assessment. Monthly respiratory IEC proportions showed smallest variability during the study period. Discussion. Use of the quality control statistics is suitable to distinguish random from systematic influence on quality indicators. IEC recordings that are not specific in pathophysiologic type or are of low grade of clinical severity, are heavily dependent on systematic documentation features. We assume that peak values, such as in times of optimised documentation discipline, better reflect reality than average values because missing reporting is much more likely than false positives.

Adult↗

PubMed1998

Effect of increased cardiac output on liver blood flow, oxygen exchange and metabolic rate during longterm endotoxin-induced shock in pigs.

We investigated hepatic blood flow, O2 exchange and metabolism in porcine endotoxic shock (Control, n = 8; Endotoxin, n = 10) with administration of hydroxyethylstarch to maintain arterial pressure (MAP)>60 mmHg. Before and 12, 18 and 24 h after starting continuous i.v. endotoxin we measured portal venous and hepatic arterial blood flow, intracapillary haemoglobin O2 saturation (Hb-O2%) of the liver surface and arterial, portal and hepatic venous lactate, pyruvate, glycerol and alanine concentrations. Glucose production rate was derived from the plasma isotope enrichment during infusion of [6,6-2H2]-glucose. Despite a sustained 50% increase in cardiac output endotoxin caused a progressive, significant fall in MAP. Liver blood flow significantly increased, but endotoxin affected neither hepatic O2 delivery and uptake nor mean intracapillary Hb-O2% and Hb-O2% frequency distributions. Endotoxin nearly doubled endogenous glucose production rate while hepatic lactate, alanine and glycerol uptake rates progressively decreased significantly. The lactate uptake rate even became negative (P<0.05 vs Control). Endotoxin caused portal and hepatic venous pH to fall significantly concomitant with significantly increased arterial, portal and hepatic venous lactate/pyruvate ratios. During endotoxic shock increased cardiac output achieved by colloid infusion maintained elevated liver blood flow and thereby macro- and microcirculatory O2 supply. Glucose production rate nearly doubled with complete dissociation of hepatic uptake of glucogenic precursors and glucose release. Despite well-preserved capillary oxygenation increased lactate/pyruvate ratios reflecting impaired cytosolic redox state suggested deranged liver energy balance, possibly due to the O2 requirements of gluconeogenesis.

Alanine Transaminase↗

PubMed1998

Clinical utility of EEG parameters to predict loss of consciousness and response to skin incision during total intravenous anaesthesia.

We studied 30 female patients undergoing elective surgery, to assess the reliability of electroencephalogram spectral edge frequency and median frequency to predict loss of consciousness and movement in response to skin incision during total intravenous anaesthesia. Each patient received a different combination of propofol (1, 2, 3, 4, 5 or 6 micrograms.ml-1) and sufentanil (0.1, 0.2, 0.3, 0.5 or 1.0 ng.ml-1) target concentrations for induction of anaesthesia using target controlled infusions, assigned randomly. In a logistic regression model, spectral edge frequency was a significant determinant of both loss of consciousness (p = 0.0006) and movement to skin incision (p = 0.0044), whereas for median frequency no significant prediction model could be established. The probabilities of 50% and 95% no response for spectral edge frequency were 13.4 Hz and 6.8 Hz, respectively. The variability of the data limited the predictive value, so that spectral edge frequency was a poor predictor and median frequency was no predictor of response in the individual patient during total intravenous propofol/sufentanil anaesthesia.

Adult↗

PubMed1998

[Laughing gas as the principle substance in assessing occupational exposure to inhalation anesthetics].

PURPOSE: In the Federal Republic of Germany limits for the chronic exposure to nitrous oxide and volatile anaesthetics have been prescribed by legislation. According to the technical rules for the handling of hazardous substances TRGS 402 it is legal to measure a single substance in a mixture of hazards, unless the behaviour of all substances is known. Studies about corresponding concentrations of nitrous oxide and volatile anaesthetics in anaesthetic working areas have not yet been carried out. METHODS: During one working week each the concentrations of nitrous oxide, enflurane and desflurane were measured by infrared spectrometry in a working area equipped with air condition and in a non-ventilated operating theatre. Corresponding concentrations of nitrous oxide were measured from the same gas samples. RESULTS: Statistical calculations showed linear correlations of the enflurane and nitrous oxide concentrations in all anaesthetic areas. No linear regression was found between the desflurane and nitrous oxide concentrations. In the working area where desflurane anaesthesias were carried out, significantly higher concentrations of nitrous oxide were observed. Nevertheless the Chi2-test showed no significant differences in the distribution of categorised measurement values. DISCUSSION: Although it is not possible to calculate desflurane concentrations from the nitrous oxide concentrations, measurement of nitrous oxide as leading substance is a valid procedure to assess the exposure of the anaesthesiology workplace to nitrous oxide and volatile anaesthetics. Significant higher nitrous oxide concentrations during desflurane anaesthesia result from early extubation of patients expiring higher concentrations of nitrous oxide.

Air Pollution, Indoor↗

PubMed1998

[A remote access system for inquiry of centrally stored data on patients suspected of malignant hyperthermia . A prototypical development for the Internet].

OBJECTIVES: Malignant hyperthermia (MH) is an inherited, potentially life-threatening syndrome of the skeletal muscles. It is a life-threatening complication of anaesthesia with a high mortality (8-10%). The risk of the patient during anaesthesia due to an overlooked predisposition for MH can be reduced by organisational measures, such as, all data of MH-susceptible patients and their families known in Germany must be brought together in a central register, MH-relevant data of patients must be readily retrievable, optional oral advice for those making an inquiry must be available. METHODS: To achieve this goal, a client-server system has been implemented: Standard Multimedia personal computers installed at the user's (anaesthetist's) site, linked to the Internet, will act as clients. On a server, relevant data of patients concerning MH-susceptibility are integrated in a central database. The newly developed software of this project ensures the legally prescribed data security on the server and the data routes. At the client's site, standard software together with automatically installed programmes from the server using Java applets ensure easy use and maintenance. IMPLEMENTATION: The total system was implemented and tested. Its functionality and high availability was demonstrated during this test period. Relevant aspects of data security were successfully examined by the data security officer of the University Hospitals of Baden-Württemberg. The user can optionally call a multifunctional teleconference which secures on-line advice if needed. This system demonstrates a safe and quick retrieval of MH relevant data of patients via Internet while at the same time guaranteeing all aspects of data protection and security. CONCLUSION: A prototypical database access system is described. It ensures safe access to patient data via Internet, while guaranteeing all aspects of data security.

Computer Communication Networks↗