Influence of acute normovolaemic haemodilution on bispectral index monitoring and propofol dose requirements.

BACKGROUND: Numerous medical and physiological conditions that might alter electroencephalography (EEG), such as hypoglycaemia, hypothermia or hypovolaemia, were shown to result in the bispectral Index (BIS) indicating an incorrect hypnotic state. Recently, acute normovolaemic haemodilution (ANH) was shown to be associated with significant impairment of cognitive functions that could alter EEG and consequently BIS monitoring, an EEG derived parameter. METHODS: In a randomised clinical study, we assessed the effect of ANH on BIS monitoring before induction and after propofol target controlled infusion (TCI) anaesthesia in 45 unmedicated patients randomly allocated to ANH with oxygen insufflation (oxygen group), ANH with air insufflation (air group), or control group. RESULTS: With ANH, mean BIS values briefly declined in the oxygen group (82+/-4) and air group (84+/-3) before returning to baseline values. The loss of consciousness time was significantly shorter, with fewer propofol TCI dose requirements, and BIS was significantly higher in the oxygen group (1.3+/-0.5 min, 2.41+/-0.15 microg/ml, 73+/-7) and air group (1.2+/-0.6 min, 2.44+/-0.17 microg/ml, 75+/-5), compared with the control group (1.7+/-0.4 min, 2.75+/-0.17 microg/ml, 61+/-5), respectively. Whereas, there was no significant difference in BIS values between the oxygen group (38+/-7), air group (36+/-5) and control group (40+/-6) at propofol TCI 4 microg/ml anaesthesia maintenance. CONCLUSIONS: BIS values briefly declined with ANH before returning to baseline values before anaesthesia induction. Despite transient ANH enhancement of propofol effect during induction, there was no significant difference in BIS values with or without ANH during propofol maintenance of anaesthesia.

Sensitivity and specificity of bispectral index for classification of overt hepatic encephalopathy: a multicentre, observer blinded, validation study.

BACKGROUND: The severity of hepatic encephalopathy is currently graded clinically using West Haven criteria and psychometric tests. OBJECTIVE: To assess the discriminative power of the bispectral index (BIS) monitor to classify the degree and progression of hepatic encephalopathy. DESIGN: A consecutive, multicentre, observer blinded validation study. SETTING: Medical University of Graz (Graz, Austria), Zhejiang University First Affiliated Hospital (Hang Zhou, China), and Cairo University (Cairo, Egypt). PATIENTS: 28 consecutive patients with hepatic encephalopathy were first enrolled at Medical University of Graz as a test set. The estimated BIS cut off values were subsequently tested in a validation set of 31 patients at Zhejiang University First Affiliated Hospital and 26 patients at Cairo University; 18 patients were reassessed later in a longitudinal study. Fifteen of 85 patients (18%) were excluded from the final analysis (11 became too agitated with high electromyographic activity; four fell asleep during the recording). RESULTS: Applying the Austrian BIS cut off values of 85, 70, and 55 for discriminating West Haven grades 1 to 4 yielded agreement between BIS classification and West Haven grades in 40 of the 46 validation patients (87%), and in 16 of the 18 follow up patients (89%). Mean (SD) BIS values differed significantly between patients with West Haven grade 1 (90.2 (2.5)), grade 2 (78.4 (6.6)), grade 3 (63.2 (4.8)), and grade 4 (45.4 (5.0)). CONCLUSIONS: BIS is a useful measure for grading and monitoring the degree of involvement of the central nervous system in patients with chronic liver disease.

Procalcitonin for early prediction of survival outcome in postoperative critically ill patients with severe sepsis.

BACKGROUND: Identification of postoperative patients at high risk of dying early after intensive care unit (ICU) admission through a fast and readily available parameter may help in determining therapeutic interventions or further diagnostic procedures that could have an impact on patients' outcome. The aim of our study was to assess the utility of procalcitonin (PCT) and other readily available parameters, as useful early (days 1-3) predictors of mortality in postoperative patients diagnosed with severe sepsis within 24 h preceding their operation. METHODS: More than a period of 2 yr, subsets of 69 postoperative patients admitted with severe sepsis and 890 non-septic ICU patients were investigated. PCT, C-reactive protein (CRP) and sequential organ failure assessment (SOFA) score were recorded over the duration of ICU stay. RESULTS: PCT area under receiver operating characteristic (ROC) curve was 0.78 on day 3 and was highly predictive of fatal outcome (0.90) at day 6. Area under ROC curve of SOFA score was 0.85 on day 3 and remained in this range until day 6. Area under ROC curves on day 3 of CRP (0.61) was non-predictive and remained non-predictive over the duration of ICU stay. CONCLUSIONS: PCT exhibited no discriminative power early after ICU admission for prediction of mortality in critically ill patients with severe sepsis, compared with a high predictive power of SOFA score on day 3. However, using PCT could still serve as a useful complementary comparator for prediction of survival outcome using the SOFA score.

Haemodynamic and catecholamine stress responses to the Laryngeal Tube-Suction Airway and the Proseal Laryngeal Mask Airway.

Supraglottic airway devices such as the ProSeal Laryngeal Mask Airway (PLMA) and Laryngeal Tube-Suction Airway (LTS) that provoke the least stress responses could be beneficial in many situations, especially in patients with cardiovascular disease. We compared the haemodynamic and catecholamine stress response of the LTS and PLMA in a randomised study of 36 patients. Mean arterial pressure, heart rate, epinephrine and norepinephrine levels were all reduced following induction of anaesthesia with no significant differences between the two groups. Following insertion of LTS, mean arterial pressure, heart rate, epinephrine and norepinephrine levels increased to pre-induction levels. However, following the insertion of the PLMA, mean arterial pressure, heart rate, epinephrine and norepinephrine levels remained significantly lower than pre-induction values. Mean arterial pressure, heart rate and epinephrine were significantly greater in the LTS group than in the PLMA group. We conclude that the LTS produces a greater and more sustained haemodynamic and catecholamine stress response than does the PLMA.

Procalcitonin and proinflammatory cytokine clearance during continuous venovenous haemofiltration in septic patients.

Procalcitonin (PCT), interleukin-6 (IL-6), tumour necrosis factor a (TNFalpha), and interleukin-1beta (IL-1beta) are important clinical prognostic markers in ICU septic patients. The goal of the study was to determine whether continuous venovenous haemofiltration (CWH), using an AN69 haemofilte, leads to elimination of PCT, TNFalpha, IL-6 and IL-1beta in 13 septic patients with multi-organ failure. At the start of haemofiltration (0), 6 and 12 hours the mean afferent plasma concentration +/- SD of PCT (10.1 +/- 9.1, 7 +/- 6, 5.9 +/- 5.7 ng/ml), IL-6 (804.6 +/- 847.6, 611.7 +/- 528.4, 575.2 +/- 539.2 pg/ml), and that of TNFalpha (4.5 +/- 2.6, 4 +/- 3.1, 3.8 +/- 2.9 pg/ml) significantly declined during CVVH. The efferent plasma concentrations were significantly lower than the corresponding afferent concentrations. PCT; IL-6 and TNFalpha were detectable in the ultrafiltrate of all patients. IL-1beta was only detectable in the plasma of eight patients and the ultrafiltrate of five patients. The plasma clearance of PCT, IL-6 and TNFalpha significantly decreased after 12 hours as a result of a decline in the adsorptive elimination of the mediators due to progressive membrane saturation. We demonstrated that if PCT, IL-6 and TNFalpha are used as clinical prognostic markers in septic patients who are treated with CWIH using an AN69 membrane, one should be aware that their plasma level could be modified by the therapy. In addition CWH could represent an appropriate tool to remove a broad spectrum of proinflammatory mediators, if such removal is required in septic patients.

Efficacy of folinic versus folic acid for the correction of hyperhomocysteinemia in hemodialysis patients.

The effectiveness of intravenous folinic acid or intravenous folic acid for the treatment of hyperhomocysteinemia of hemodialysis patients is unknown. In a randomized, controlled, double-blind trial, 66 hemodialysis patients were administered either 15 mg of folic acid or an equimolar amount (16.1 mg) of folinic acid intravenously three times weekly. Normalization of total homocysteine (tHcy) plasma levels after 4 weeks of treatment was achieved in 10 patients (30.3%) in the folic-acid group and 6 patients (18.2%; P: = 0.389) in the folinic-acid group (normalization at any time during the study period in 39.4% and 33.3% of the patients; P: = 0.798). The relative reduction in tHcy plasma levels at week 4 was 32.2% in the folic-acid group and 34.1% in the folinic-acid group. A high baseline tHcy plasma concentration (P: = 0.00001), methylenetetrahydrofolate reductase (MTHFR) 677TT/1298AA genotype (P: = 0.03540), and low red blood cell folate concentrations (P: = 0.02285) were associated with a better relative response to treatment. Normalization of tHcy plasma levels was dependent on a lower baseline tHcy level (P: = 0.01976), younger age (P: = 0.00896), and MTHFR 677TT/1298AA or 677CT/1298AC genotypes (P: = 0.00208 and P: = 0.02320, respectively). A 4-week course of intravenous folinic acid is not superior to intravenous folic acid in reducing elevated tHcy plasma levels in hemodialysis patients. The response to treatment is predicted by tHcy plasma level, red blood cell folate content, and MTHFR genotype.

Noninvasive measurement of pulmonary vascular resistances by assessment of cardiac output and pulmonary transit time.

RATIONALE AND OBJECTIVES: Pulmonary vascular resistance is of special interest in many diseases. Usually it is determined invasively by catheterization, but cardiac output and pulmonary transit time can be ascertained by several noninvasive methods. METHODS: Fourteen heart recipients (age 34-71 years) were examined by electron-beam CT of the heart. Cine and flow studies were performed using a total of 60 mL of contrast and a breath-hold of 20 seconds. RESULTS: A mathematical model for calculating pulmonary vascular resistances from noninvasively measured cardiac outputs and pulmonary transit times was developed. Right-sided heart catheterization served as the reference method. CONCLUSIONS: The formula created seems to allow a clinically valid estimate of pulmonary vascular resistance from noninvasively acquired data.

Comparison of a new piezoelectric train-of-four neuromuscular monitor, the ParaGraph, and the Relaxometer mechanomyograph.

The ParaGraph is a new device for monitoring neuromuscular function using a piezoelectric motion sensor. In 20 patients, monitoring of neuromuscular block produced by cisatracurium 0.1 mg kg-1 was compared using the ParaGraph and a Relaxometer 2 mechanomyograph. The ParaGraph was quick to set up, and easy to operate and interpret. There were no significant differences in the time to 100% depression of T1/T0, time to 25% recovery of T1/T0 or time to recovery of T1/T0 from 25% to 75%, measured by the two monitors. When the difference between the two monitors was plotted against the average of the two measurements, the limits of agreement for T1/T0 (-42.95, +53.98%) and the train-of-four ratio, T4/T1 (-0.28, +0.21) were too wide to allow the values given by the two monitors for individual patients to be used interchangeably.

Total intravenous anesthesia with remifentanil, propofol and cisatracurium in end-stage renal failure.

PURPOSE: To compare recovery parameters of total intravenous anesthesia (TIVA) with remifentanil and propofol, hemodynamic responses to perioperative events, and pharmacodynamic parameters of cisatracurium in 22 end-stage renal failure and 22 normal renal function patients. METHODS: Anesthesia was induced with 2-3 mg x kg(-1) propofol and 1 microg x kg(-1) remifentanil and maintained with 75 microg x kg(-1) x min(-1) propofol and propofol initial infusion of 0.2 microg x kg(-1) x min(-1) propofol. Arterial pressure and heart rate were maintained by remifentanil infusion rate adjustments. The first twitch (T1) was maintained at 25% by an infusion of cisatracurium. RESULTS: There was no difference in the time to maintenance of adequate respiration, date of birth recollection, first analgesic administration, between the renal failure (4.8+/-2.5, 7.8+/-3.2, 12.3+/-5.3 min respectively) and the control group (5.2+/-2.8, 8.1+/-3.1, 12.7+/-5.5 min): nor were there any differences in the time to 25% T1 recovery, T1 recovery from 25% to 75%, or cisatracurium infusion rate between the renal failure group (32.1 +/-10.8 min, 18.2+/-5.5 min, 0.89+/-0.29 microg x kg(-1) min(-1) respectively) and the control group (35.9 (7.9 min, 18.4+/-3.8 min, 0.95+/-0.22 microg x kg(-1) x min(-1)). CONCLUSION: End-stage renal failure does not prolong recovery from TIVA with remifentanil and propofol, or the recovery from cisatracurium neuromuscular block.

Assessment of accelerography with the TOF-GUARD: a comparison with electromyography.

The TOF-GUARD is a new device for monitoring the neuromuscular function using acceleration measurement. It is quick and easy to apply and does not require a rigid support for the arm. Forty-one patients were studied to assess the monitoring of vecuronium neuromuscular block (NMB) using accelerography by the TOF-GUARD compared with electromyography by the Relaxograph. Although the mean first twitch (T1%) and mean train-of-four (TOF) ratios measured by the TOF-GUARD corresponded to a certain extent with the Relaxograph, the wide variations of the values for individual patients measured by the TOF-GUARD compared with the Relaxograph and the differences in clinical duration and recovery index between the two monitors do not allow the values of the two monitors to be used interchangeably. The levels at intubation as well as at full recovery of the patients can be assessed equally by the two monitors. Thus, the TOF-GUARD is a reliable clinical monitor in daily anaesthesia practice.

A comparison of mivacurium infusion requirements between young and elderly adult patients.

Forty-one patients of ASA classes I or II, undergoing elective surgery, were divided into two groups: young, 18-41 years (mean 31), and elderly, 64-79 years (mean 71). The integrated evoked compound electromyogram of the adductor pollicis muscle elicited by stimulation of the ulnar nerve was used to monitor the neuromuscular block of the non-depolarizing muscle relaxant mivacurium. An initial dose of mivacurium 0.15 mg kg-1 allowed six excellent, nine good, three adequate and three poor intubations in the young group, and nine excellent, eight good, three adequate and no poor intubations in the elderly group. Patients recovered until 1-2 stimuli of the train-of-four were visible, and an infusion of mivacurium was started (0.5 mg kg-1 h-1). At 3 min intervals the rate was adjusted by +/- 0.05 mg kg-1 h-1 (+/- 10% initial rate), as indicated during anaesthesia which was provided by nitrous oxide in oxygen, infusion of propofol, and fentanyl supplements. In the first 30 min, the young group had their mivacurium requirement increased to 111.4% (0.56 mg kg-1 h-1), which was reached in the first 15 min, after which it gradually decreased to 92.9% (0.46 mg kg-1 h-1). The elderly group's requirements decreased from the start, to 78.5% (0.39 mg kg-1 h-1). The difference between the two groups was significant (P < 0.05). After the first 30 min, both groups requirements decreased, with time, but with no statistically significant differences.

[Results of various reconstructive methods after subcutaneous mastectomy and objective evaluation of tissue fibrosis with a new measurement procedure]. / Ergebnisse verschiedener rekonstruktiver Verfahren nach subkutaner Mastektomie und Objektivierung der Gewebsfibrose mit einer neuen Messmethode.

Of 35 patients undergoing subcutaneous mastectomy performed within the last 15 years, 25 were evaluated for follow-up studies. Reconstruction had been achieved either using silicone implants or autologous tissue formed from the resulting dermal-fat pedicles. The patients were interviewed for subjective results. In addition, firmness of the breast according to the classification of Baker was investigated. The compressibility of the breast was electronically measured, employing a new compression device. In 13 patients, the breast was distorted after reconstruction with implants. The deformity did not correlate with submuscular or subcutaneous placement of the implants. The aesthetic results after dermal-fat pedicle techniques were superior to reconstruction with silicone implants. Compressibility to 32% of breast diameter was defined to be a border value between a soft and firmer breast, correlating with clinical conditions between Baker 2 and Baker 3.

[30 degree trunk elevation of the patient and quality of lumbar epidural anesthesia. Effects of elevation in operations on the lower extremities]. / 30 grad Rumpfhochlagerung des Patienten und Qualität der lumbalen Epiduralanästhesie. Auswirkungen der Lagerung bei Operationen an der unteren Extremität.

The spread and intensity of lumbar epidural anaesthesia are unpredictable. Moreover, segments L5 and S1 are frequently missed. In this study the effect of 30 degrees trunk elevation on the spread and intensity of lumbar epidural sensory and motor blockade and on the cardiovascular system were studied. METHODS. After oral premedication with 7.5 mg midazolam, 30 patients 20 to 40 years of age, ASA 1-2, were randomly allocated to one of two groups according to their body position during injection of 20 ml 2% lidocaine (3 + 8 + 9 ml) into a lumbar epidural catheter (L2/3 or L3/4) and during the following 30 min: supine horizontal position or supine 30 degrees trunk elevation with 30 degrees leg elevation (hammock position). The patients received 500 ml Ringer solution before the epidural injection, followed by more Ringer solution. Systolic and diastolic blood pressures and heart rate were monitored noninvasively every 5 min; 30 min after the epidural injection the spread of analgesia (dullness of pinprick) and anaesthesia (no sensation of pinprick) as well as motor block according to Bromage were tested. A spread of anaesthetic segments including T12 to L3 was considered adequate for hip surgery, L3 to L5 for knee surgery, and L3 to S2 for foot surgery. Student's t-test, ANOVA, chi-square (Wilcoxon), and Mann-Whitney tests were used for statistical analysis. P < 0.05 was considered statistically significant. RESULTS. The median cephalad level of analgesia was lower in patients with the hammock position than those with the horizontal position (L1 vs T10; P < 0.05). There was no significant difference in the cranial level of anaesthesia (L2 vs L1) (Table 2). No significant difference was seen in the number of patients having adequate anaesthesia for hip surgery. Anaesthesia in the segments L5 and S1 was seen in 2/15 patients in the horizontal position and 8/15 patients in the hammock position (P < 0.05). The hammock position resulted in a higher percentage of patients having adequate anaesthesia for knee surgery (60% vs 13%; P < 0.05) and foot surgery (53% vs 13%; P < 0.05) (Table 3). Motor block was more profound in patients in the hammock position (Table 4). Blood pressure and heart rate did not change significantly in patients in the horizontal position (Fig. 1); there was a decrease in both systolic (7 mmHg) and diastolic (5 mmHg) blood pressures in patients in the hammock position. Heart rate did not change significantly (Fig. 2). No patient needed vasopressor support; the body position could be maintained in all patients during the observation period. One or two epidural reinjections according to the spread of anaesthesia 30 min after the first injection and to the scheduled operation resulted in adequate anaesthesia in every patient. DISCUSSION. More patients in the hammock position developed adequate anaesthesia in the relevant segments for knee and foot operations than patients in the horizontal position. These included the frequently missed segments L5 and S1. Patients in the hammock position had a clinically insignificant drop in systolic and diastolic blood pressure. In contrast to the young and healthy patients in this study, more severe cardiovascular changes might result in geriatric and/or ill patients subjected to a hammock position. For this reason, use of the technique in geriatric and/or ill patients requires special attention.

Pain threshold and subjectively perceived epidural sensory blockade with 0.5% bupivacaine.

We investigated the relationship between patients' pain thresholds and the quality of the subjectively perceived epidural sensory blockade (SPESB). The pain thresholds of 50 patients were evaluated with a modification of the submaximum effort tourniquet technique. There was a significant correlation between pain threshold and the number of subjectively perceived anesthetic and analgesic segments, the likelihood of developing an extensive SPESB being greater in patients with higher pain thresholds. Forty-one percent of patients with pain scores of less than 10 mm on the visual analogue scale, but no patient with a pain score of 20 mm or more, developed anesthesia in ten or more spinal segments.

Positive end-expiratory pressure and the damaged right ventricle. An experimental open versus closed chest study.

Hemodynamic changes after isolated impairment of right ventricular function (produced by increasing afterload by temporary banding of the pulmonary artery) were studied in 22 ventilated pigs during increased levels of positive end-expiratory pressure (4, 8, 12, and 16 cm H2O). In the open chest group, application of positive end-expiratory pressure produced only a slight decrease of cardiac index. After right ventricular damage a decrease of cardiac index of more than 25% occurred only when higher levels of positive end-expiratory pressure were applied. In contrast to the open chest group, the closed chest group showed more distinct cardiovascular responses after positive end-expiratory pressure. In the damaged right ventricle with a positive end-expiratory pressure of 16 cm H2O, right ventricular end-diastolic pressure increased more than 100%. With positive end-expiratory pressure, cardiac index decreased 34% before and 47% after right ventricular damage. We conclude that positive end-expiratory pressure induces a more pronounced decrease in cardiac index if right ventricular function is impaired. During open chest conditions with lower levels of positive end-expiratory pressure, these changes are only small, however, and probably irrelevant. During closed chest conditions, the hemodynamic changes are much more pronounced. High right ventricular end-diastolic pressures resulting from impaired right ventricular contractility as well as from high levels of positive end-expiratory pressure may have an impact on biventricular function and right ventricular coronary driving pressure.