Stroke volume variation (SVV) is a good and easily obtainable predictor of fluid responsiveness, which can be used to guide fluid therapy in mechanically ventilated patients. During major abdominal surgery, inappropriate fluid management may result in occult organ hypoperfusion or fluid overload in patients with compromised cardiovascular reserves and thus increase postoperative morbidity. The aim of our study was to evaluate the influence of SVV guided fluid optimization on organ functions and postoperative morbidity in high risk patients undergoing major abdominal surgery. Patients undergoing elective intraabdominal surgery were randomly assigned to a Control group (n = 60) with routine intraoperative care and a Vigileo group (n = 60), where fluid management was guided by SVV (Vigileo/FloTrac system). The aim was to maintain the SVV below 10% using colloid boluses of 3 ml/kg. The laboratory parameters of organ hypoperfusion in perioperative period, the number of infectious and organ complications on day 30 after the operation, and the hospital and ICU length of stay and mortality were evaluated. The local ethics committee approved the study. The patients in the Vigileo group received more colloid (1425 ml [1000-1500] vs. 1000 ml [540-1250]; P = 0.0028) intraoperatively and a lower number of hypotensive events were observed (2[1-2] Vigileo vs. 3.5[2-6] in Control; P = 0.0001). Lactate levels at the end of surgery were lower in Vigileo (1.78 ± 0.83 mmol/l vs. 2.25 ± 1.12 mmol/l; P = 0.0252). Fewer Vigileo patients developed complications (18 (30%) vs. 35 (58.3%) patients; P = 0.0033) and the overall number of complications was also reduced (34 vs. 77 complications in Vigileo and Control respectively; P = 0.0066). A difference in hospital length of stay was found only in per protocol analysis of patients receiving optimization (9 [8-12] vs. 10 [8-19] days; P = 0.0421). No difference in mortality (1 (1.7%) vs. 2 (3.3%); P = 1.0) and ICU length of stay (3 [2-5] vs. 3 [0.5-5]; P = 0.789) was found. In this study, fluid optimization guided by SVV during major abdominal surgery is associated with better intraoperative hemodynamic stability, decrease in serum lactate at the end of surgery and lower incidence of postoperative organ complications. Current Controlled Trials ISRCTN95085011.

/pdf/intraoperative-fluid-optimization-using-stroke-volume-24vrb03maa.pdf

Intraoperative fluid optimization using stroke volume variation in high risk surgical patients: results of prospective randomized study

When assessing the accuracy and precision of a new technique for cardiac output measurement, the commonly quoted criterion for acceptability of agreement with a reference standard is that the percentage error (95% limits of agreement/mean cardiac output) should be 30% or less. We reviewed published data on four different minimally invasive methods adapted for use during surgery and critical care: pulse contour techniques, esophageal Doppler, partial carbon dioxide rebreathing, and transthoracic bioimpedance, to assess their bias, precision, and percentage error in agreement with thermodilution. An English language literature search identified published papers since 2000 which examined the agreement in adult patients between bolus thermodilution and each method. For each method a meta-analysis was done using studies in which the first measurement point for each patient could be identified, to obtain a pooled mean bias, precision, and percentage error weighted according to the number of measurements in each study. Forty-seven studies were identified as suitable for inclusion: N studies, n measurements: mean weighted bias [precision, percentage error] were: pulse contour N = 24, n = 714: -0.00 l/min [1.22 l/min, 41.3%]; esophageal Doppler N = 2, n = 57: -0.77 l/min [1.07 l/min, 42.1%]; partial carbon dioxide rebreathing N = 8, n = 167: -0.05 l/min [1.12 l/min, 44.5%]; transthoracic bioimpedance N = 13, n = 435: -0.10 l/min [1.14 l/min, 42.9%]. None of the four methods has achieved agreement with bolus thermodilution which meets the expected 30% limits. The relevance in clinical practice of these arbitrary limits should be reassessed.

http://www.conference.co.nz/files/docs/poster%20session%20c%20abstracts%208.pdf

Minimally invasive measurement of cardiac output during surgery and critical care: a meta-analysis of accuracy and precision.

Bland-Altman analysis is used for assessing agreement between two measurements of the same clinical variable. In the field of cardiac output monitoring, its results, in terms of bias and limits of agreement, are often difficult to interpret, leading clinicians to use a cutoff of 30% in the percentage error in order to decide whether a new technique may be considered a good alternative. This percentage error of ± 30% arises from the assumption that the commonly used reference technique, intermittent thermodilution, has a precision of ± 20% or less. The combination of two precisions of ± 20% equates to a total error of ± 28.3%, which is commonly rounded up to ± 30%. Thus, finding a percentage error of less than ± 30% should equate to the new tested technique having an error similar to the reference, which therefore should be acceptable. In a worked example in this paper, we discuss the limitations of this approach, in particular in regard to the situation in which the reference technique may be either more or less precise than would normally be expected. This can lead to inappropriate conclusions being drawn from data acquired in validation studies of new monitoring technologies. We conclude that it is not acceptable to present comparison studies quoting percentage error as an acceptability criteria without reporting the precision of the reference technique.

/pdf/bench-to-bedside-review-the-importance-of-the-precision-of-515o7tt9n6.pdf

Bench-to-bedside review: the importance of the precision of the reference technique in method comparison studies--with specific reference to the measurement of cardiac output.

https://emcrit.org/wp-content/uploads/2013/12/marik-noninvasive-cards-output.pdf

Noninvasive cardiac output monitors: a state-of the-art review.

Advances in medical care have led to increasing numbers of complex, high-risk obstetric patients. Specialist training and a sound knowledge of normal maternal physiology are essential to optimize outcomes. One of the earliest observed changes is peripheral vasodilatation; this causes a fall in systemic vascular resistance and triggers physiological changes in the cardiovascular and renal systems, with 40-50% increases in cardiac output and glomerular filtration rates. Safety concerns over Swan Ganz catheters have driven the increasing interest in alternative techniques, such as echocardiography, thoracic bioimpedance and pulse contour analysis, although their exact roles in future obstetric high-dependency care have yet to be established. Analysis of arterial blood gases is fundamental to the management of sick patients, and correct interpretation can be aided by a systematic approach. Observation charts are almost ubiquitous in all aspects of medicine, but little evidence exists to support their use in the high-dependency setting.

/pdf/physiological-changes-of-pregnancy-and-monitoring-210mb9thhg.pdf

Physiological changes of pregnancy and monitoring

Institutional Review Board (IRB) approval of this research could not be verified during an investigation by the Landesarztekammer Rheinland-Pfalz (the State Medical Association of Rheinland-Pfalz in Germany). As a result, this article has been retracted, in accordance with the Journal’s regulations, at the request of the Directors and Board of the British Journal of Anaesthesia. Lack of IRB approval means that the research was unethical, and that IRB approval for the research was misrepresented in the published article. It does not mean that the research results per se are fraudulent. For further information please see Retraction .

Semi-invasive monitoring of cardiac output by a new device using arterial pressure waveform analysis: a comparison with intermittent pulmonary artery thermodilution in patients undergoing cardiac surgery

BACKGROUND The aim of this study was to assess the practicality of the ProSeal laryngeal mask (PS-LMA) airway during laparoscopic surgery with capnoperitoneum compared to endotracheal intubation (ET). METHODS Prospective, randomized study. 104 patients undergoing gynaecologic, laparoscopic surgery were allocated randomly to two groups: 1. ET-group (n = 50). 2. PS-LMA-group (n = 54). Total intravenous anaesthesia was performed by the same anaesthesiologist. MEASUREMENTS Mean arterial pressure, heart rate, at 4 and circuit pressure at 2 measurement points, and the incidences of coughing and sore throat. Insertion of the ET and the PS-LMA was scored by using a four-point scale. Ease of placing the gastric tube was judged by measuring the number of attempts at insertion and the insertion times. A p-value of < 0.05 was considered as significant. RESULTS There were no differences between PS-LMA and ET concerning circuit pressure at any measurement point. At the end of anaesthesia, mean arterial pressure (92 +/- 13 vs. 100 +/- 14 mmHg; p < 0.01) and heart rate (66 +/- 13 vs. 76 +/- 14 beats/min; p < 0.01) were lower in the PS-LMA-group compared to the ET-group. At the end of anaesthesia 25 patients of the ET-group coughed but nobody in the PS-LMA-group (p < 0.00001). There was no difference with regard to postoperative sore throat. The insertion of the PS-LMA was easier compared to ET (p < 0.05), but we found no significant difference concerning insertion times. Fewer attempts at insertion of the gastric tube were necessary in the PS-LMA-group than in the ET-group (p < 0.01), whereas insertion times did not differ. CONCLUSION The PS-LMA is a convenient and practicable approach for anaesthesia in patients undergoing laparoscopic surgery.

[ProSeal-laryngeal mask versus endotracheal intubation in patients undergoing gynaecologic laparoscopy].

Background and objective: To evaluate the current clinical attitude in enteral nutrition support and motility disorders in adult critically ill patients on German intensive care units. Methods: A total of 1493 questionnaires, including 25 items on the medical environment, treatment of motility disorders and enteral nutrition, were sent to German intensive care units in September 2005. Responses were collected during a 2-month period. Results: A total of 593 questionnaires were returned (response rate 41%). The intensive care units were mainly led by anaesthesiologists (63%) or internists (17%). Standard nutrition protocols were used in 44%. Feeding was mainly started as a combined enteral-parenteral regimen (70%). Early enteral nutrition was performed in 58% using a volume of 250-500 mL (66%) and increased by 200-400 mL day-1 (55%). It was mainly delivered by gastric tube (76%) via continuous pump systems (72%) with short interruption intervals of <4 h (86%). Enteral nutrition solutions were mainly standard polymeric formulae (86%). Modified solutions for diabetics and those with renal or liver failure were uncommonly used; immunonutrition did not play a role. Prokinetic agents, especially metoclopramide, laxatives and neostigmine, were routinely used (39%). Further therapeutic options in motility dysfunction included purgative enemas (96%), gastrografin (72%) and colon massage (39%). Conclusions: The concept of early enteral nutrition has been well established and approved in German intensive care units, though the recommendations only meet level C criteria in the current ESPEN guidelines. The current survey may serve for further updates on practical nutrition support in intensive care medicine.

Nutrition support and treatment of motility disorders in critically ill patients - results of a survey on German intensive care units.

OBJECTIVE Pain on injection is one of the most described side-effects of the intravenous application of propofol. This study was designed to assess the efficacy of lidocaine 40 mg in preventing incidence and severity of injection pain for two different propofol solvents. METHODS In a double-blind and prospective study 202 patients were enrolled and randomized to 4 different groups: group A receiving 2 ml NaCl 0.9 % and propofol-LCT (Disoprivan; AstraZeneca), group B 40 mg lidocaine and propofol-LCT, group C received 2 ml NaCl 0.9 % and propofol-MCT/LCT (Propofol-Lipuro, B. Braun Melsungen AG) and group D 40 mg lidocaine and propofol-MCT/LCT. According to the protocol, all patients were cannulated with a 18-G venous cannula at the dorsum of the hand and no other medicament was injected before the study drug. Time interval between test agents and propofol application in a dosage of 2 mg/kg was one minute. Severity of pain was evaluated during propofol injection over 30 seconds until loss of consciousness using a 4-point rating scale. RESULTS The incidence of injection pain did not differ between propofol-LCT and propofol-MCT/LCT (64 % and 53 %). Propofol-MCT/LCT significantly reduced the severity of pain compared to propofol-LCT (p < 0.05). The application of lidocaine resulted in a significant reduction in incidence (Propofol-MCT/LCT: 16 %; Propofol-LCT: 31 %) and severity of injection pain compared to placebo. CONCLUSION Propofol-MCT/LCT showed a significant advantage compared to propofol-LCT considering the severity of injection pain, but not in reducing the incidence of pain. The use of lidocaine resulted in a significant reduction of incidence and severity of injection pain for both propofol solvents.

[Injection pain secondary to propofol-MCT/LCT and propofol-LCT--comparison of prophylaxis with lidocaine].

BACKGROUND AND OBJECTIVE Inhalational anaesthetics have been associated with hepatotoxicity. Even desflurane, with its low solubility in blood and tissues, and its minimal hepatic biotransformation, is known to affect hepatic integrity. The effects of propofol on hepatic function are, however, a matter of controversy. Alpha-glutathione S-transferase (alpha-GST), a sensitive and specific biomarker for hepatic integrity, was measured to assess the influence of total intravenous anaesthesia (TIVA) with propofol vs. anaesthesia with desflurane. METHODS Forty-two patients scheduled for elective prostatectomy were randomly allocated to receive either desflurane, fentanyl and thiopental (desflurane group) or propofol and remifentanil (TIVA group). Depth of anaesthesia was guided by bispectral index. Plasma concentrations of alpha-GST and aminotransferases were measured before induction of anaesthesia (TO), at the end of surgery (T1), as well as 2 h (T2) and 24 h (T3) postoperatively. Haemodynamic parameters and bispectral index values were documented. RESULTS alpha-GST increased significantly in the desflurane group from TO (3.0 +/- 2.2 microg L(-1)) to T1 and T2 (5.5 +/- 4.3 and 5.6 +/- 3.7 microg L(-1), respectively), whereas no changes were seen in the TIVA group. alpha-GST values above the normal upper limit (> 7.5 microg L(-1)) were seen in 24% of the patients receiving desflurane. Aminotransferases remained unchanged in both groups throughout the study period. CONCLUSIONS The use of propofol as part of a TIVA regimen seems to have no influence on hepatocellular function during and after surgery. In contrast, patients receiving desflurane showed a transient slight, but significant, increase of alpha-GST to above the normal upper limit after anaesthesia, although this was without further clinical relevance.

Insignificant effect of desflurane-fentanyl-thiopental on hepatocellular integrity--a comparison with total intravenous anaesthesia using propofol-remifentanil.

T. Schöllhorn

Papers

Semi-invasive monitoring of cardiac output by a new device using arterial pressure waveform analysis: a comparison with intermittent pulmonary artery thermodilution in patients undergoing cardiac surgery

[ProSeal-laryngeal mask versus endotracheal intubation in patients undergoing gynaecologic laparoscopy].

Nutrition support and treatment of motility disorders in critically ill patients - results of a survey on German intensive care units.

[Injection pain secondary to propofol-MCT/LCT and propofol-LCT--comparison of prophylaxis with lidocaine].

Insignificant effect of desflurane-fentanyl-thiopental on hepatocellular integrity--a comparison with total intravenous anaesthesia using propofol-remifentanil.