[Anesthesia in obstetrics: Tried and trusted methods, current standards and new challenges]. / Anästhesie in der Geburtshilfe: Altbewährtes, gegenwärtige Standards und neue Herausforderungen.

Obstetric analgesia and anesthesia have some specific aspects, which in particular are directly related to pathophysiological alterations during pregnancy and also to the circumstance that two or even more individuals are always affected by complications or therapeutic measures. This review article deals with some evergreens and hot topics of obstetric anesthesia and essential new knowledge on these aspects is described. The article summarizes the talks given at the 16th symposium on obstetric anesthesia organized by the Scientific Committee for Regional Anaesthesia and Obstetric Anaesthesia within the German Society of Anaesthesiology. The topics are in particular, special features and pitfalls of informed consent in the delivery room, challenges in education and training in obstetric anesthesia, expedient inclusion of simulation-assisted training and further education on risk minimization, knowledge and recommendations on fasting for the delivery room and cesarean sections, monitoring in obstetric anesthesia by neuraxial and alternative procedures, the possibilities and limitations of using ultrasound for lumbal epidural catheter positioning in the delivery room, recommended approaches in preparing peridural catheters for cesarean section, basic principles of cardiotocography, postoperative analgesia after cesarean section, the practice of early bonding in the delivery room during cesarean section births and the management of postpartum hemorrhage.

Detection of hypotension during Caesarean section with continuous non-invasive arterial pressure device or intermittent oscillometric arterial pressure measurement.

BACKGROUND: The intensified use of spinal anaesthesia (SPA) for Caesarean section significantly contributed to a decreased maternal mortality and morbidity. Nevertheless, one of the major side-effects is hypotension after SPA with potential negative effects on the fetus. Owing to discontinuous oscillometric measurements (non-invasive arterial pressure, NIAP), hypotensive episodes may be missed. Recently, a continuous NIAP measurement device (CNAP) with acceptable agreement with the mean invasive AP was introduced. We hypothesized that CNAP detects hypotensive episodes more reliably compared with NIAP measurements. METHODS: A total of 65 women undergoing Caesarean section under SPA were included in the study analysis. A total of 888 NIAP measurements obtained at 3 min cycles, starting from before SPA and continued until delivery, were analysed. RESULTS: When averaged over all cycles, the lowest systolic AP identified by CNAP in each cycle [105 mm Hg, (24.4)] was significantly lower (P<0.001) than the average of the individual corresponding single NIAP measurements [126 mm Hg (22.1)] and highest CNAP average [126 mm Hg (24.5)]. Hypotension (systolic AP <100 mm Hg) was detected in 39% of all cycles with CNAP and in 9% with NIAP. Hypotension was detected in 91% of the patients based on CNAP and in 55% based on NIAP. Fetal acidosis defined by an umbilical vein pH under 7.25 did not occur when the lowest systolic AP measured by CNAP was above 100 mm Hg. CONCLUSIONS: The CNAP device detected more hypotensive episodes after SPA and significantly lower AP compared with NIAP. AP monitoring based on CNAP may improve haemodynamic management in this patient population with potential benefit for the fetus.

Airway management in pediatric patients using the Glidescope Cobalt®: a feasibility study.

BACKGROUND: Video laryngoscopes are claimed to improve airway management. Several studies showed an equal or better glottic view using the Glidescope® compared with direct laryngoscopy in adults and in paediatric patients. Many case reports also described successful intubation in patients with a difficult airway. The Glidescope Cobalt® is a modified Glidescope® with a disposable sheath. Data on clinical application in paediatric patients is insufficient. METHODS: Twenty-four pediatric patients with a mean age of 27 months [range, 1-142] undergoing general anesthesia were included into this feasibility study. Cormack and Lehane grade was evaluated using a Macintosh blade. Tracheal intubation was performed using the Glidescope Cobalt®. Number of attempts, time to intubation, Cormack and Lehane (C&L) grade and a subjective score were noted for both a resident and an attending anesthesiologist. RESULTS: With the Glidescope Cobalt® the C&L grade improved in all patients with grade 2 or 3 to 1 and deteriorated in one case from C&L grade 1 to 2. The C&L grade remained unchanged in 15 patients (62.5%). C&L grades between resident and attending anesthesiologist were equal. Tracheal intubation was successful in 92% with a stylet-armed tube and in 8% using an unarmed tube with a Magill forceps, respectively. Time to intubation was median 50.5 [range, 22-93] seconds. CONCLUSION: The Glidescope Cobalt® presented suitable for use in children. C&L grade was significantly improved in all patients with a C&L grade of 2 or 3. Especially for educational purposes in pediatric anesthesia it provides a good view for all participants.

The effect of posture and anaesthetic technique on the surgical pleth index.

The surgical pleth index has been shown to correlate with surrogate variables of nociception during general anaesthesia, and it has been suggested to be of use as a depth of anaesthesia monitor. However, little is known about confounding factors. As the main determining variables are based on both central and peripheral autonomic regulatory mechanisms, we hypothesised that changing a patient`s posture may produce a marked effect. We studied the effects of posture change in 45 patients who were randomly assigned to receive general (n = 15) or spinal anaesthesia with (n = 15) or without sedation (n = 15), as well as 15 awake volunteers. Mean (SD) values of the surgical pleth index after adoption of the lithotomy position were reduced from 57 (22) to 21 (6) under general anaesthesia, 63 (15) to 31 (9) under spinal anaesthesia alone, and 52 (14) to 22 (8) under spinal anaesthesia with sedation (all p < 0.01). In healthy volunteers, the surgical pleth index increased from 37 (13) to 57 (11) (p < 0.01) after 30° head-up tilt and was reduced from 35 (11) to 25 (11) after head-down tilt (p < 0.05). Change in posture has a marked effect on the surgical pleth index which lasts for at least 45 min, and this must be considered when interpreting the displayed values.

Investigation of the agreement of a continuous non-invasive arterial pressure device in comparison with invasive radial artery measurement.

BACKGROUND: Arterial pressure (AP) monitoring should be accurate, easy to use, free of risks, and ideally continuous. The continuous non-invasive arterial pressure (CNAP) device is non-invasive and provides continuous pressure readings. This study was performed to compare the agreement of CNAP and invasive AP monitoring. METHODS: Ninety patients undergoing surgery under general anaesthesia were enrolled. Invasive pressure monitoring was established at the radial artery. CNAP monitoring using a finger sensor recording was begun before induction of anaesthesia. Statistical analysis was conducted with the Bland-Altman method for comparisons of repeated measures. RESULTS: We obtained 16 843 valid pressure readings from 85 patients. Mean (sd) bias during maintenance of anaesthesia was: systolic AP: 4.2 (16.5) mm Hg; mean AP (MAP): -4.3 (10.4) mm Hg; and diastolic AP: -5.8 (6) mm Hg. The results of a subgroup analysis of patients who had a mean intra-arterial pressure of <70 mm Hg were as follows: systolic pressure: -0.3 (9.7) mm Hg; mean pressure: -6.8 (7.6) mm Hg; and diastolic pressure: -7.9 (7.2) mm Hg. Bias and percentage error during the induction period were greater in both the main and subgroup analyses, probably due to recalibration being omitted after induction. CONCLUSIONS: The CNAP monitor showed an acceptable agreement and was interchangeable with invasive pressure monitoring for MAP during normotensive conditions. During induction of anaesthesia and when the AP was low, the agreement was less good and interchangeability was not achieved. These results suggest that CNAP is not statistically equivalent to invasive monitoring during all periods of anaesthesia but may be a useful additional AP monitor.

Evaluation of the surgical stress index during spinal and general anaesthesia.

BACKGROUND: Although in modern anaesthesia, monitoring depth of anaesthesia and quality of neuromuscular block are routine, monitoring of analgesia still remains challenging. Recently, the surgical stress index (SSI), derived from finger photoplethysmographic signal, was introduced as a surrogate variable reflecting the nociception-antinociception balance. This study aimed at evaluating the SSI in patients undergoing regional anaesthesia either alone or combined with sedation compared with patients undergoing general anaesthesia (GA). METHODS: Seventy-one patients undergoing general (n=24) or spinal anaesthesia with (n=24) or without sedation (n=23) were included. SSI was measured the day before surgery and at defined time points during anaesthesia and surgery and also in the recovery room. SSI was compared with haemodynamic variables like heart rate and systolic arterial pressure. RESULTS: The SSI was higher in patients undergoing spinal anaesthesia [mean 65, CI (59.3-70.5)] compared with GA [48 (39.9-56.4), P<0.01], and baseline [41 (37.3-44.2), P<0.001]. During spinal anaesthesia with sedation [44 (36.2-50.9)], it was comparable with the baseline level (P>0.05). In comparison with baseline, SSI in the recovery room was higher in patients after GA [59 (48.4-67.9), P<0.025] but not after spinal anaesthesia [53 (47.6-60.1), P>0.05] or after spinal anaesthesia with sedation [54 (45.8-65.1), P>0.05]. Changes of the SSI were not reflected by changes of haemodynamic variables. CONCLUSIONS: In fully awake patients under spinal anaesthesia, the SSI does not reflect the nociception-antinociception balance. This may be due to the influence of mental stress on the sympathetic nervous system. Even light sedation attenuates these influences.

A comparison of the i-gel with the LMA-Unique in non-paralysed anaesthetised adult patients.

SUMMARY: This study assessed two disposable devices; the newly developed supraglottic airway device i-gel and the LMA-Unique in routine clinical practice. Eighty patients (ASA 1-3) undergoing minor routine gynaecologic surgery were randomly allocated to have an i-gel (n = 40) or LMA-Unique (n = 40) inserted. Oxygen saturation, end-tidal carbon dioxide, tidal volume and peak airway pressure were recorded, as well as time of insertion, airway leak pressure, postoperative sore-throat, dysphonia and dysphagia for each device. Time of insertion was comparable with the i-gel and LMA-Unique. There was no failure in the i-gel group and one failure in the LMA-Unique group. Ventilation and oxygenation were similar between devices. Mean airway pressure was comparable with both devices, whereas airway leak pressure was significantly higher (p < 0.0001) in the i-gel group (mean 29 cmH(2)O, range 24-40) compared with the LMA-Unique group (mean 18 cmH(2)O, range 6-30). Fibreoptic score of the position of the devices was significantly better in the i-gel group. Post-operative sore-throat and dysphagia were comparable with both devices. Both devices appeared to be simple alternatives to secure the airway. Significantly higher airway leak pressure suggests that the i-gel may be advantageous in this respect.

Influence of different remifentanil concentrations on the performance of the surgical stress index to detect a standardized painful stimulus during sevoflurane anaesthesia.

BACKGROUND: Although measurement of cerebral hypnotic drug effect and muscle relaxation is common clinical routine during anaesthesia, a reliable measurement of the neurophysiological effects evoked by a painful stimulus is still missing. Recently, the surgical stress index (SSI) has been introduced as a surrogate measure of 'nociception'. The present study aimed to examine the influence of increasing remifentanil concentrations on the ability of SSI to detect a standardized painful stimulus during sevoflurane anaesthesia. METHODS: Twenty-four patients received incremental or decremental doses of 0, 2, and 4 ng ml(-1) remifentanil effect-site concentration (Ce(remi)) during 0.7 MAC sevoflurane. Painful tetanic stimulation was applied at least 5 min after changing Ce(remi). SSI, heart rate (HR), response entropy (RE), state entropy (SE), RE-SE difference, and bispectral index (BIS) were obtained in each patient before and after stimulation. Further prediction of an author-defined response to painful stimulus was analysed. RESULTS: SSI and BIS, but not HR, SE, RE, or RE-SE difference were significantly altered after stimulation. Change in SSI (Delta SSI) was significantly dependent on Ce(remi), as Delta SSI was [median (inter-quartile range)] 20 (15-31), 10 (1-19), and 3 (1-10) at 0, 2, and 4 ng ml(-1) Ce(remi). In 10 out of 63 cases, SSI detected response to stimulation, not detected by another variable. SSI was unable to predict movement after stimulation as P(K) value is 0.59 (0.09). CONCLUSIONS: The SSI response to tetanic stimulation was dependent on the remifentanil concentration.

Influence of anaesthesia resident training on the duration of three common surgical operations.

We investigated the influence of resident training on anaesthesia workflow of three standard procedures--laparoscopic cholecystectomy, diagnostic gynaecological laparoscopy and transurethral prostate gland resection (TURP)--comparing 259 non-emergency resident vs 341 consultant cases from 20 German hospitals. Each hospital provided 10 random cases for each procedure, yielding 600 cases for analysis. Standard time intervals as documented in the hospital information system were: 'Case Time' (the time from the start of anaesthesia induction to discharge of the patient to the recovery area) and 'Anaesthesia Control Time' (which was the Case Time minus the time from the start of surgery to the end of surgical closure). Case Time was significantly shorter for consultants in all three procedures (p < 0.05, analysis of variance) and Anaesthesia Control Time shorter for consultants only in gynaecological laparoscopy and TURP. Patient comorbidity, patient age and geographical location of the hospital were not influential factors in the analysis of variance. We conclude that resident training significantly increases duration of elective operative times.

[The gynecological TURP syndrome. Severe hyponatremia and pulmonary edema during hysteroscopy]. / Das gynäkologische "TUR-Syndrom". Schwere Hyponatriämie und Lungenödem während operativer Hysteroskopie.

Fluid overload and dilutional hyponatremia are rare but typical complications of endoscopic transurethral resection of the prostate gland (TURP syndrome). Less commonly, this complication caused by excessive absorption of hypotonic, electrolyte-free non-conductive distention solution, may also occur during endoscopic surgery of the uterus, e.g. operative hysteroscopy. A case report is presented of a 44-year-old woman scheduled for operative hysteroscopy for intracavital myoma under general anaesthesia, suffering from severe absorption syndrome leading to hyponatremia of 106 mEq/l and pulmonary edema necessitating subsequent admission to ICU. Anatomical and physiological as well as technical aspects of this syndrome are discussed. Recommendations for anesthesiology management are offered and a possible treatment of acute hyponatremia is discussed.

Use of heart rate variability analysis to determine the risk of cardiac ischaemia in high-risk patients undergoing general anaesthesia.

The aim of this study was to investigate the use of pre-operative heart rate variability analysis to predict postoperative cardiac events (identified by 24 h Holter-ECG recording and an increase of creatine kinase MB) in high-risk cardiac patients. Length of hospital stay, the incidence of postoperative cardiac ischaemia and cardiac events after discharge were recorded. Fifty patients were assigned by the presence of cardiac events and the heart rate variability in 17 patients with an event was compared with 33 patients without. Total power was identified as a predictive parameter. The usefulness of this test was assessed in a second group of 50 patients. The incidence of cardiac events detected by Holter-ECG recording or an increased creatine kinase MB was greater and the duration of hospital stay longer in the 26 patients with total power < 400 ms(2).Hz(-1) compared with those with total power > 400 ms(2).Hz(-1) (eight and four patients and 10 (7) days (mean (SD)), vs 1 (p < 0.05) and 0 (p < 0.05) patients and 6 (2) days (p < 0.05), respectively). The total power of high-risk cardiac patients predicted postoperative cardiac events and extended length of hospital stay.

The effects of interrupted or continuous administration of sevoflurane on preconditioning before cardio-pulmonary bypass in coronary artery surgery: comparison with continuous propofol.

Volatile anaesthetics have been shown to exert cardioprotective properties in experimental and clinical studies. However, the mode of administration may influence these cardioprotective effects. The present study was designed to compare the effect of interrupted administration of sevoflurane before cardiopulmonary bypass with continuous sevoflurane administration and with propofol-only anaesthesia, on cardioprotection as assessed by left ventricular performance and myocardial cell damage during coronary artery bypass grafting. Forty-two patients scheduled for coronary bypass surgery were randomly assigned to one of three groups: propofol-only (P; n = 14), continuous (SevoC; n = 14) and interrupted sevoflurane administration (SevoI; n = 14). Myocardial cell damage as assessed by Troponin T (cTNT) and creatine kinase MB (CK-MB) were chosen as the primary endpoints and echocardiographic myocardial performance index (MPI) measurements were also performed. Up to 48 h postoperatively, in group SevoI, postoperative cTNT values (mean (SD) 0.13 (0.04) ng x ml(-1)) were significantly (p < 0.05) lower than both the P (0.26 (0.31) ng x ml(-1)) and SevoC (0.25 (0.17) ng x ml(-1)) groups. CK-MB levels were also significantly (p < 0.05) lower in the SevoI group at 24 h after surgery and MPI significantly improved compared with both the P and SevoC groups. There was, however, no difference with respect to cytokine release and length of stay in either the intensive care unit or in the hospital. We conclude that prior interrupted sevoflurane administration confers some cardioprotection as compared with continuous sevoflurane administration or propofol-based anaesthesia.

Does heart rate variability predict hypotension and bradycardia after induction of general anaesthesia in high risk cardiovascular patients?

This study investigated whether heart rate variability predicts haemodynamic events in high risk patients, defined as Revised Cardiac Risk Index score = 3, scheduled for general anaesthesia. Fifty patients underwent baseline measurement of heart rate variability and were then assigned according to haemodynamic events (hypotension or bradycardia) after standardised induction of anaesthesia into 'stable' (n = 39) and 'unstable' patients (n = 11). Unstable patients had significantly lower baseline total power. Total power < 500 ms2 x Hz(-1) was associated with high sensitivity and specificity for the prediction of hypotension or bradycardia. Prospectively, 29 patients with total power < 500 ms2 x Hz(-1) were compared with 21 patients with total power > 500 ms2 x Hz(-1). Differences were found in the lowest mean arterial pressure and heart rate after induction of anaesthesia. We conclude that the pre-operative total power of heart rate variability in high risk patients may indicate the occurrence of haemodynamic events with high sensitivity and specificity. Heart rate variability may be a suitable tool to identify patients at high risk of a haemodynamic event and may be used to indicate need for intensive monitoring and, perhaps, prophylactic treatment.

Changes in heart rate variability may reflect sympatholysis during spinal anaesthesia.

BACKGROUND: To investigate if changes in low-to-high frequency ratio (LF/HF), low frequency (LF) and high frequency (HF) heart rate variability reflect autonomic regulation during spinal anaesthesia (SA) in pregnant women scheduled for elective Caesarean section. METHODS: Prospective clinical trial. Systolic blood pressure (SBP) and heart rate variability were analysed at baseline, 5 min after SA and 15 min after SA. Patients were assigned by baseline LF/HF. Group LF/HF < 2.5 (n= 52) was compared to group LF/HF > 2.5 (n= 48). Non-parametric tests for statistical analysis. RESULTS: Group LF/HF > 2.5 showed a significant decrease in LF/HF and LF as well as an increase in HF during SA (median, range): baseline LF/HF [4.0 (3.2/4.8)] decreased to 2.3 (1.3/3.4) at event 15 min after SA (P < 0.001). Baseline LF = 59(43/71)% decreased to 40 (27/55)% at event 15 min after SA (P < 0.05). Baseline HF = 15(13/22)% increased to 26(15/41)% at event 15 min after SA (P < 0.05). In contrast, group LF/HF < 2.5 demonstrated only moderate changes in LF/HF, LF and HF during SA. SBP decreased significantly in group LF/HF > 2.5 (median and range) lowest SBP group LF/HF > 2.5: 80 (50/127 mmHg vs. group LF/HF < 2.5: 109 (104/142) mmHg, P < 0.001. Decrease of SBP before and after SA was correlated with a decrease in LF/HF, LF, and HF, respectively: LF/HF - SBP: r= 0.30, r(2)= 0.09, P < 0.001; LF - SBP: r= 0.25, r(2)= 0.06, P < 0.05, HF, NS. CONCLUSIONS: Changes in heart rate variability parameters in the course of SA may reflect a decrease in sympathetic activity and relative increase in parasympathetic activity as a result of the block. In the course of SA, the more pronounced the changes in heart rate variability were the more distinct the hypotension.

[Comparison of premedication regimes. A randomized, controlled trial]. / Prämedikationsregime im Vergleich. Eine prospektive, randomisierte, kontrollierte Studie.

BACKGROUND: The effect of two premedication regimes with different benzodiazepines on anxiety, hemodynamic data, sympatho-adrenal activity, and bispectral index (BIS) was evaluated during the variable time period prior to induction of anesthesia. PATIENTS AND METHODS: This prospective, double-blind study was performed with 50 ASA class I and II patients. Patients were randomized either to group I: evenings 22.00 hours 50 mg chlorazepate dipotassium (CD), mornings 07.00 hours 25 mg CD, placebo 30 min prior to anesthesia (on demand) or group II: evenings 50 mg CD, mornings placebo, 7.5 mg midazolam on demand. RESULTS: In group I the BIS dropped after administration of 25 mg CD and was significantly lower at 08.00, 09.00 and 10.00 hours compared to baseline (mean+/-SD; 90+/-5, 87+/-7 and 87+/-7, respectively vs. 95+/-4; p<0.05), whereas the BIS of group II did not decrease significantly. Both groups did not differ significantly with respect to all variables obtained throughout the study period. CONCLUSION: We conclude that 50 mg CD the evening before surgery prevented an increase of anxiety and sympatho-adrenal activity in both groups and might therefore be sufficient as premedication. Fixed time application of 25 mg CD at 07.00 hours or 7.5 mg midazolam 30 min prior to anesthesia did not further affect these variables preoperatively.

The influence of xenon on regulation of the autonomic nervous system in patients at high risk of perioperative cardiac complications.

BACKGROUND: As xenon anaesthesia (XE) does not produce haemodynamic depression its use may be of benefit in patients at high risk of intraoperative haemodynamic instability and perioperative cardiac complications. XE (n=22) was compared with total i.v. anaesthesia (TIVA, n=22) for differences in autonomic regulation, peri- and postoperative performance. METHODS: Patients undergoing abdominal aortic surgery were studied at five events: T1: baseline awake; T2: anaesthesia induction; T3: before aortic cross-clamping; T4: after aortic cross-clamping; T5: after aortic declamping. T3-T5: end-tidal xenon concentration 60 (5)%. Intraoperative analysis: heart rate, heart rate variability, blood pressure and cardiac output. Postoperative analysis: 24 h Holter ECG, intensive care unit and hospital stay, and patient's outcome after 6 months. RESULTS: XE in contrast to TIVA increased parasympathetic and decreased sympathetic activity. Median low to high frequency decreased significantly in the XE group after start of XE (P<0.05) and remained significantly lower during all events after start of XE as compared with TIVA (P=0.0001). After start of XE heart rate of these patients was significantly lower as compared with TIVA (P=0.04). Cardiac output increased significantly in TIVA after aortic declamping (P<0.05). Outcome parameters did not differ significantly between groups. CONCLUSIONS: XE patients demonstrated lower sympathetic and higher parasympathetic activity as compared with TIVA patients. This was reflected by significant differences in haemodynamics but did not correlate with a better postoperative outcome. Thus, it remains controversial whether XE provides benefits in high risk patients.

Bispectral index-controlled anaesthesia for electroconvulsive therapy.

BACKGROUND: The suggested induction dose of methohexital for electroconvulsive therapy (ECT) varies widely influencing efficacy of ECT and safety of anaesthesia. Bispectral index (BIS), a monitor of consciousness, may be useful to assure adequate hypnosis with optimized methohexital dose. METHODS: Patients with medically resistant major depression (ICD10), scheduled for multiple ECT's, were studied. Depth of anaesthesia was BIS controlled. ECT was not performed until BIS dropped below 50. Initially anaesthesia was induced with methohexital 1.0 mg kg(-1), and stepwise reduced by 0.1 mg kg(-1) during consecutive treatments. If BIS did not drop below 50, the methohexital was supplemented by further boluses of 0.5 mg kg(-1), until the desired level of hypnosis was reached. The adequacy of the anaesthetic recommendation for methohexital (1.0-1.5 mg kg(-1)) as well as the psychiatric recommendation (0.75-1 mg kg(-1)) was investigated. RESULTS: One-hundred and nine ECT's in 14 patients were studied. The recommended anaesthetic dose (1.0-1.5 mg kg(-1)) was inadequate in 40% of the treatments, with 12% exceeding 1.5 mg kg(-1), and 28% below 1.0 mg kg(-1). Psychiatric recommendation (0.75-1.0 mg kg(-1)) was inadequate in 49%, with 39% exceeding 1.0 mg kg(-1) and 10% undershooting at 0.75 mg kg(-1). CONCLUSIONS: Methohexital for ECT showed a great variability, exceeding as well as undershooting the dosage recommendations widely. BIS monitoring may be useful to secure adequate hypnosis during muscle relaxation and treatment and may optimize ECT efficacy.

Comparison of xenon-based anaesthesia compared with total intravenous anaesthesia in high risk surgical patients.

Xenon, a noble gas with anaesthetic and analgesic properties, has gained renewed interest due to its favourable physical properties which allow a rapid emergence from anaesthesia. However, high costs limit its use to a subset of patients who may benefit from xenon, thereby offsetting its costs. To date, there are only limited data available on the performance of xenon in high risk patients. We studied 39 patients with ASA physical status III undergoing aortic surgery. The patients were randomly assigned to either a xenon (Xe, n = 20) or a TIVA (T, n = 19) group. Global cardiac performance and myocardial contractility were assessed using transoesophageal echocardiography, and myocardial cell damage with troponin T and CK-MB. Echocardiographic measurements were made prior to xenon administration, following xenon administration, and after clamping of the abdominal aorta, after declamping and at corresponding time points in the TIVA group. Laboratory values were determined repeatedly for up to 72 h. Data were analysed using two-way anova factoring for time and anaesthetic agent or with ancova comparing linear regression lines. No significant differences were found in global myocardial performance, myocardial contractility or laboratory values at any time during the study period. Mean (SEM) duration of stay on the ICU (xenon: 38 +/- 46 vs. TIVA 25 +/- 15 h) or in hospital (xenon: 14 +/- 12 vs. TIVA 10 +/- 6 days) did not differ significantly between the groups. Although xenon has previously been shown to exert superior haemodynamic stability, we were unable to demonstrate an advantage of xenon-based anaesthesia compared to TIVA in high risk surgical patients.