Cardioplegia and ventricular late potentials in cardiac surgical patients.

BACKGROUND AND OBJECTIVE: Ventricular late potentials (LP) recording with signal-averaged electrocar- diogram allow identifying patients at risk of sudden death and ventricular tachycardia. Cardiac surgery with cardiopulmonary bypass (CPB) could predispose to the development of myocardial ischemia related to imperfect cardioplegia. To the best of our knowledge, no study investigated the protection of cardioplegia and CPB regarding the occurrence of LP in patients without previous myocardial infarction and undergoing cardiac surgery. METHODS: In 61 elective patients scheduled for cardiac surgery involving CPB, signal-averaged electrocar- diogram was performed the day before and 24-48 h after the surgery. The electrodes were positioned according to Frank's orthogonal derivations. Twenty five patients were excluded because of poor quality signals, leaving 36 patients (age, 64 ± 14) available for the analyses. An abnormal signal-averaged electrocardiogram was considered when ≥2 of the recorded indexes were present. McNemar's tests were performed on the dichotomized values to investigate differences in pre-post scores. RESULTS: The mean CPB duration was of 110 ± 57 min. Patients scheduled for cardiac surgery do not exhibited LP after CPB (no significant difference in pre-post CPB scores, P = NS). The probability of a patient with a negative score transitioning to a positive score was 0.23 (P = NS). CONCLUSIONS: The present study in cardiac surgical patients suggests that cardioplegia associated to CPB has no significant impact on the occurrence of LP, irrespective of surgery performed.

[Microcirculatory alterations in critically ill patients: pathophysiology, monitoring and treatments]. / Altérations de la microcirculation dans les états de choc: physiopathologie, surveillance et traitement.

Microcirculation represents a complex system devoted to provide optimal tissue substrates and oxygen. Therefore, pathophysiological and technological knowledge developments tailored for capillary circulation analysis should generate major advances for critically ill patients' management. In the future, microcirculatory monitoring in several critical care situations will allow recognition of macro-microcirculatory decoupling, and, hopefully, it will promote the use of treatments aimed at preserving tissue oxygenation and substrate delivery.

[Physiopathologic aspects of microcirculation in intensive care]. / Aspects physiopathologiques de la microcirculation aux soins intensifs.

In critical care patients, microvascular alterations and perfusion heterogeneity play an important role in the persistence of cellular hypoxia despite a satisfactory functioning of the macrocirculation. Advance in the knowledge of microcirculatory pathophysiology, and its relation with the macrocirculation could be in the future a way to improve the outcome of critically ill patients. Moreover, the evolution of clinical practice towards microcirculation monitoring as a standard of care, with new therapeutic targets aimed to increase tissue perfusion, could be a revolution in critical care practice.

[Cardiopulmonary interactions in patients under positive pressure ventilation]. / Interdépendance coeur-poumons chez le patient ventilé par pression positive.

Heart-lung interactions during positive-pressure ventilation are characterized by an extreme sensibility to the patient's intravascular volume status. Indeed, a fall in cardiac output due to decreased ventricular preload can be observed when initiating positive-pressure ventilation. This phenomenon is due to the close anatomic-functional association between heart and lungs, and to the fact that pulmonary volume and intrathoracic pressure variations cyclically modify heart-lung interactions. The present review address the questions of the physiological and physiopathological effects of positive-pressure ventilation on the right and left venous returns, and on pulmonary and systemic vascular resistances.

Adding a dialysis dose to continuous hemofiltration increases survival in patients with acute renal failure.

Acute renal failure (ARF) in critically ill patients is associated with high mortality. Optimal method and dose of continuous renal replacement therapy could improve survival in these patients. We studied the hypothesis that an increase in dialysis dose obtained by continuous veno-venous hemodiafiltration (CVVHDF) is associated with a better survival than continuous veno-venous hemofiltration (CVVH) among critically ill patients with ARF. In a prospective randomized trial, these two methods were compared in patients undergoing renal replacement therapy in two intensive care units (ICUs). The patients had either CVVH (1-2.5 l/h replacement fluid) or continuous CVVHDF (1-2.5 l/h replacement fluid+1-1.5 l/h dialysate) according to their body weight. 28- and 90-day mortalities, renal recovery, and duration of ICU stay were the main outcome measures. Two hundred and six patients were randomized from October 2000 to December 2003. Twenty-eight-day survivals (%) were, respectively, 39 and 59 (P=0.03) in the CVVH and CVVHDF groups. Three months survivals (%) were, respectively, 34 and 59 (P=0.0005) in the CVVH and CVVHDF groups. Apache II score, age, baseline blood urea nitrogen, and hemodiafiltration (hazard ratio 0.59, 95% confidence interval 0.40-0.87; P=0.008) were independent predictors of survival at 90 days. Renal recovery rate among survivors (71 versus 78% in the CVVH and CVVHDF groups respectively, P=0.62) was not affected by the type of renal replacement therapy. These results suggest that increasing the dialysis dose especially for low molecular weight solutes confers a better survival in severely ill patients with ARF.

Lack of effect of combination antibiotic therapy on mortality in patients with pneumococcal sepsis.

In order to determine whether combination antibiotic therapy decreases mortality after severe pneumococcal infection, a retrospective study of a cohort of 1,840 adult patients with severe sepsis or septic shock enrolled in two multicenter clinical trials between 1994 and 1999 was conducted. Among 107 patients with monobacterial pneumococcal sepsis, the case-fatality rate was 20% (five of 25) for patients who received antibiotic monotherapy compared with 19.5% (16 of 82) for patients who received combination therapy (adjusted hazard ratio, 1.1; 95% CI, 0.4-3.1). Similarly, monotherapy did not increase the risk of death (adjusted hazard ratio, 1.0; 95% CI, 0.2-4.8) among bacteremic patients (n=75). However, the latter analysis may have been underpowered (power, 58%) to detect a difference in mortality. Overall, in contrast to recently published reports, these results suggest that combination antibiotic therapy does not decrease mortality after severe pneumococcal sepsis.

Impact of enteral versus parenteral nutrition on the incidence of fungal infections: a retrospective study in ICU patients on mechanical ventilation with selective digestive decontamination.

BACKGROUND: Infections are an important cause of morbidity and mortality in patients in intensive care units (ICUs). Fungal infections have increased substantially over recent years and fungi have become one of the important pathogens in ICU patients. This study tests the hypothesis that the incidence of fungal infections is lower in critically ill patients under mechanical ventilation receiving enteral rather than total parenteral nutrition. METHODS: By using a prospectively built database, we analyzed retrospectively the charts of 110 critically ill, intubated patients hospitalized in surgical and medical ICUs and receiving selective digestive topical decontamination (SDD), which consisted of administering non-absorbable antibiotics. Patients without contraindications, and expected to be intubated for more than 72 h, received enteral nutrition within 24 h after intubation. Patients with contraindications for enteral nutrition received total parenteral nutrition, which was discontinued when the criteria for enteral nutrition were met. The incidence of fungal infections in both subgroups of patients was compared. RESULTS: Seventy-nine patients received enteral nutrition and 31 total parenteral (10 patients did not meet the inclusion criteria). Both subgroups were similar with regard to their APACHE II score, age, sex distribution and comorbidities at the time of study entry. No difference was observed in the rate of fungal infections between enteral nutrition (5/29) and total parenteral nutrition (7/71) patient groups. CONCLUSION: No significant decrease in the incidence of fungal infections in critically ill patients receiving SDD was observed between those receiving enteral and total parenteral nutrition.

Cefepime versus imipenem-cilastatin for treatment of nosocomial pneumonia in intensive care unit patients: a multicenter, evaluator-blind, prospective, randomized study.

In a randomized, evaluator-blind, multicenter trial, we compared cefepime (2 g three times a day) with imipenem-cilastatin (500 mg four times a day) for the treatment of nosocomial pneumonia in 281 intensive care unit patients from 13 centers in six European countries. Of 209 patients eligible for per-protocol analysis of efficacy, favorable clinical responses were achieved in 76 of 108 (70%) patients treated with cefepime and 75 of 101 (74%) patients treated with imipenem-cilastatin. The 95% confidence interval (CI) for the difference between these response rates (-16 to 8%) failed to exclude the predefined lower limit for noninferiority of -15%. In addition, therapy of pneumonia caused by an organism producing an extended-spectrum beta-lactamase (ESBL) failed in 4 of 13 patients in the cefepime group but in none of 10 patients in the imipenem group. However, the clinical efficacies of both treatments appeared to be similar in a secondary intent-to-treat analysis (95% CI for difference, -9 to 14%) and a multivariate analysis (95% CI for odds ratio, 0.47 to 1.75). Furthermore, the all-cause 30-day mortality rates were 28 of 108 (26%) patients in the cefepime group and 19 of 101 (19%) patients in the imipenem group (P = 0.25). Rates of documented or presumed microbiological eradication of the causative organism were similar with cefepime (61%) and imipenem-cilastatin (54%) (95% CI, -23 to 8%). Primary or secondary resistance of Pseudomonas aeruginosa was detected in 19% of the patients treated with cefepime and 44% of the patients treated with imipenem-cilastatin (P = 0.05). Adverse events were reported in 71 of 138 (51%) and 62 of 141 (44%) patients eligible for safety analysis in the cefepime and imipenem groups, respectively (P = 0.23). Although the primary end point for this study does not exclude the possibility that cefepime was inferior to imipenem, some secondary analyses showed that the two regimens had comparable clinical and microbiological efficacies. Cefepime appeared to be less active against organisms producing an ESBL, but primary and secondary resistance to imipenem was more common for P. aeruginosa. Selection of a single agent for therapy of nosocomial pneumonia should be guided by local resistance patterns.

Propofol and midazolam versus propofol alone for sedation following coronary artery bypass grafting: a randomized, placebo-controlled trial.

The aim was to compare the efficacy and side-effects of propofol combined with a constant, low dose of midazolam versus propofol alone for sedation. In a prospective, randomized and double-blinded study, 60 male patients scheduled for elective coronary bypass grafting were enrolled. Postoperatively, patients were stratified to receive either a continuous intravenous infusion of midazolam 1 mg/h or placebo. Target Ramsay sedation score was 3 to 5 corresponding to conscious sedation. An intention-to-treat design for propofol was performed to reach target sedation. Efficacy of sedation was statistically significantly higher in the group midazolam + intention-to-treat with propofol compared with the group placebo + intention-to-treat with propofol (91% vs 79%; P=0.0005). Nine of 27 patients in the midazolam group (33.4%) and nine of 26 patients in the placebo group (34.6%) needed no supplementary propofol. Weaning time from mechanical ventilation was longer in the midazolam group whether or not they required supplemental propofol when compared with placebo group (all: 432 +/- 218 min vs 319 +/- 223 min; P=0.04; supplementary propofol: 424 +/- 234 min vs 265 +/- 175 min; P=0.03). The cumulative number of patients remaining intubated was significantly higher in the group midazolam + propofol compared with the group placebo + propofol (P=0.03). In conclusion, target sedation is reached slightly more often by the co-administration of propofol and a low dose of midazolam, but weaning time from mechanical ventilation is prolonged by the co-administration of propofol and a low dose of midazolam.

Expression of an alpha7 duplicate nicotinic acetylcholine receptor-related protein in human leukocytes.

We examined the potential expression and function of alpha7 nicotinic acetylcholine receptors (nAChRs) in leukocytes. RT-PCR with alpha7 specific primers revealed the presence of the receptor mRNA in leukocytes. Immunoblotting and immunofluorescence experiments demonstrated the expression of a protein that is recognized by alpha7 specific antibodies. However, nicotine and acetylcholine (ACh) failed to elicit current in leukocytes. Binding experiments with alpha-bungarotoxin rhodamine conjugated were negative, illustrating the absence of a high-affinity binding site. RT-PCR analysis revealed the selective expression of the dupalpha7 mRNA. These data indicate that leukocytes express in their membrane the dupalpha7 protein but its physiological role remains to be identified.

Arterial mycotic aneurysm rupture following kidney-pancreatic transplantation with exocrine pancreatic drainage into the bladder: an unusual observation.

In this case report, we describe two patients who received a kidney-pancreatic transplant through technique of exocrine pancreatic drainage into the bladder, and who subsequently developed arterial mycotic aneurysms at the site of the arterial anastomosis of the homograft.

Ecstasy ingestion and fulminant hepatic failure: liver transplantation to be considered as a last therapeutic option.

Severe adverse effects due to 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) are reported with increasing frequency in the medical literature. The signs of acute toxicity most often seen are fulminant hyperthermia, hyperexcitatory states, acute renal failure and hyponatraemia. In 1992, hepatotoxicity was also described with unexplained jaundice and hepatomegaly after ingestion of MDMA. We report a case of severe toxic hepatitis following ingestion of MDMA with fulminant hepatic failure which required auxiliary liver transplantation. The diagnosis was necrotic toxic hepatitis following ecstasy ingestion. The outcome was successful, and the patient was discharged from ICU 20 d after surgery. Hepatotoxic effects of MDMA seem infrequent, but may be lethal; liver transplantation is the ultimate therapeutic option in some cases.

Evaluation of two processed EEG analyzers for assessment of sedation after coronary artery bypass grafting.

OBJECTIVES: Processed EEG monitoring has been suggested for sedation depth evaluation in intensive care unit (ICU) patients. The present study investigated the efficacy of two processed EEG monitors using SEF90% or SEF95% and BIS to differentiate between conscious (Ramsay score 4) and unconscious sedation (Ramsay score 6). DESIGN AND SETTING: Prospective, randomized trial in a surgical ICU of a university teaching hospital. PATIENTS: Patients recovering from elective coronary bypass grafting. INTERVENTION: One of two EEG analyzers was installed (A: Aspect A-1000 measuring SEF95% and BIS; D: Drager pEEG measuring SEF90%). At ICU admission unconscious sedation (Ramsay score 6), and at three 30-min intervals conscious sedation (Ramsay score 4) were investigated. MEASUREMENTS AND RESULTS: Fourteen patients were monitored by A and 14 by D. The interindividual variability (coefficient of variation 32-69 %) was large for all three processed EEG methods. SEF90% of analyzer D and BIS of analyzer A showed a statistically significant difference between unconscious and conscious sedation (11 +/- 3 and 17 +/- 6 Hz, p = 0.005; 74 +/- 10 and 83 +/- 10, p = 0.02). Positive and negative predictive values for SEF90% of analyzer D (0.57, 95% CI 0.34-0.77; and 0.92, 95% CI 0.64-0.99) and BIS of analyzer A (0.55, 95 % CI 0.32-0.76; and 0.87, 95 % CI 0.60-0.98) were too low for discrimination between conscious and unconscious sedation. CONCLUSIONS: The use of processed EEG monitoring cannot be recommended for assessing sedation depth after cardiac surgery.

A lack of evidence of superiority of propofol versus midazolam for sedation in mechanically ventilated critically ill patients: a qualitative and quantitative systematic review.

UNLABELLED: Propofol and midazolam are often used for sedation in the intensive care unit. The aim of this systematic review was to estimate the efficacy and harm of propofol versus midazolam in mechanically ventilated patients. A systematic search (Medline, Cochrane Library, Embase, bibliographies), any language, up to June 1999 was performed for reports of randomized comparisons of propofol with midazolam. Data from 27 trials (1624 adults) were analyzed. The average duration of sedation varied between 4 and 339 h. In 10 trials, the duration of adequate sedation was longer with propofol (weighted mean difference 2.9 h; 95% confidence interval [CI], 0.2-5.6 h). In 13 trials (mostly postoperative), sedation lasted 4 to 35 h; in 9 of those, average weaning time from mechanical ventilation with propofol was 0.8-4.3 h; with midazolam it was 1.5-7.2 h (weighted mean difference 2.2 h [95% CI, 0.8 to 3.7 h]). In 8 trials, sedation lasted 54 to 339 h; there was a lack of evidence for difference in weaning times. Arterial hypotension (relative risk 2.5 [95% CI, 1.3 to 4.5]; number-needed-to-treat, 12), and hypertriglyceridemia (relative risk 12.1 [95%CI, 2.9 to 49.7]; number-needed-to-treat, 6) occurred more often with propofol. The duration of adequate sedation time is longer with propofol compared with midazolam. In postoperative patients with sedation <36 h, weaning is faster with propofol. IMPLICATIONS: The duration of adequate sedation time is longer with propofol compared with midazolam. In postoperative patients with sedation < 36 h, weaning is faster with propofol.

Review of medical prevention of vasospasm after aneurysmal subarachnoid hemorrhage: a problem of neurointensive care.

Cerebral vasospasm remains a devastating medical complication of aneurysmal subarachnoid hemorrhage (SAH). It is associated with high morbidity and mortality rates, even after the aneurysm has been secured surgically or radiologically. A great deal of experimental and clinical research has been conducted in an effort to find ways to prevent this complication. The literature includes extensive coverage of in vivo animal model studies of SAH and vasospasm. These experimental studies have contributed to tremendous advances in the understanding of the mechanisms leading to cerebral vasospasm. Most of the experimental settings, however, have demonstrated varying levels of ability to predict accurately what occurs in human SAH. Therefore, although animal models have been developed to test new therapies, most of the treatment effects have been shown to be less compelling when trials have been conducted in clinical settings. The interpretation of current literature is complicated further by the imprecise estimation of the incidence of cerebral vasospasm, which is due to various degrees of clinical expression, ranging from the absence of symptoms in the presence of increased blood flow velocities at transcranial Doppler or vessel diameter reduction at angiography to neurological manifestations of severe ischemic deficits. In addition, a change over time in the incidence pattern of human SAH and vasospasm, possibly related to improved surgical techniques and overall patient management, may have occurred. This topic review collects the relevant literature on clinical trials investigating prophylactic therapies for cerebral vasospasm in patients with aneurysmal SAH and emphasizes the need for large clinical trials to confirm the results derived from clinical experience. In addition, it points out some experimental therapies that may hold promise in future clinical trials to prevent the occurrence of vasospasm.

Intravenous amiodarone or magnesium sulphate is not cost-beneficial prophylaxis for atrial fibrillation after coronary artery bypass surgery.

Our aims were to examine whether the administration of amiodarone or magnesium sulphate after coronary artery bypass graft surgery (CABG) could reduce the occurrence of atrial fibrillation, and to identify the risk factors associated with atrial fibrillation after CABG. Patients scheduled for elective CABG (n = 155) were allocated randomly, in a controlled double-blind study, to receive immediately after surgery a 72-h infusion of amiodarone (900 mg per 24 h), magnesium (4 g per 24 h) or placebo (0.9% NaCl; 50 ml per 24 h) intravenously. A 72-h Holter ECG was recorded concomitantly. The primary end-point was the prevention of atrial fibrillation; its onset was considered as prophylactic failure. An interim safety analysis was performed in 147 patients. The cumulative occurrence of atrial fibrillation was 27% in the placebo group, 14% in the amiodarone group (P = 0.14) and 23% in the magnesium group (P = 0.82). Although amiodarone delayed the onset of the first tachyarrhythmic episode (P = 0.02), it was associated with the need for longer periods of vasoactive drug infusion and invasive monitoring and a longer stay in the intensive care unit. Variables associated with the onset of atrial fibrillation were older age (odds ratio 1.9) and a plasma magnesium concentration at 24 h of less than 0.95 mmol litre-1 (odds ratio 6.7). Postoperative administration of amiodarone reduced the occurrence of atrial fibrillation after elective CABG surgery, but was associated with a longer duration of cardiovascular instability and longer need for intensive care; magnesium prophylaxis had no effect. Advanced age and a low plasma magnesium concentration are risk factors for postoperative atrial fibrillation.

[Start of an adult living donor liver transplantation program in Switzerland]. / Début d'un programme adulte de donneurs vivants de foie en Suisse.

The shortage of cadaver organs has prompted transplant centres to seek new sources of grafts. While living-donor left lobe transplantation (segments II and III) is an established procedure for children, living donor right liver transplantation (segments V, VI, VII, VIII), which can provide adequate liver mass for an average-sized adult patient, is technically more demanding and potentially associated with higher risks for the donor. In view of the permanent shortage of organs in Switzerland, we started an adult living donor liver transplantation programme in 1999 with the approval of the Clinical Ethics Committee of Geneva University Hospitals. Donor evaluation was performed only after the recipient had been officially registered for transplantation in the national waiting list. Preoperative evaluation consisted of a preliminary information phase with blood tests and Doppler ultrasonography, a second phase with radiological non invasive investigations (CT scan with volume measurements, magnetic resonance cholangiography) and a third phase including liver biopsy and angiography. A formal psychiatric evaluation was performed in all cases and detailed consent was required. Eight potential donors were investigated, 5 were not retained because of too small right liver or steatosis, and 3 were accepted (wife, son, sister). Living-donor hepatectomy was performed without interrupting the vascular blood flow. The liver graft was perfused ex-situ with University of Wisconsin solution. The grafts were anastomosed to the preserved vena cava of the recipient and the portal and arterial anastomoses were performed without interposition grafts, with short cold ischaemic times in the 3 cases. The graft-to-recipient weight ratio ranged from 1.04 to 1.12%. The grafts worked immediately; the post-operative course in the 3 recipients was unremarkable and no rejection episode occurred. Significant complications were observed in one donor (percutaneously drained bilioma and spontaneously resolved popliteal sensory palsy). Living-donor right liver transplantation is a potentially valuable solution to the increasing shortage of donor organs. The procedure can be performed safely provided stringent criteria for donor selection, for donor-recipient coupling (> 1% graft to body weight ratio) and for centre selection (experience in liver surgery, reduced and split liver transplantation) are applied.

Effects of guidelines implementation in a surgical intensive care unit to control nighttime light and noise levels.

OBJECTIVE: Because of around-the-clock activities, environmental noise and light are among the many causes of sleep disturbance in an intensive care unit (ICU). The implementation of guidelines may potentially change behavior rules and improve sleep quality. DESIGN: A prospective interventional study, observing the effects of simple nighttime guidelines on light and noise levels in an ICU. SETTING: A modern surgical ICU, subdivided into six identical three-bed rooms. PATIENTS: Critically ill adult patients. INTERVENTION: Between two observation periods, five guidelines were implemented to decrease both light and noise during the night shift in the patient's room. MEASUREMENT: Light levels and noise levels were obtained using a luxmeter and a sound level meter [A-weighted decibels (dB) scale] and were monitored continuously from 11 pm to 5 am both before (period P1) and after (period P2) the implementation of guidelines. MAIN RESULTS: Similar patient's gravity and nursing workload scores were observed between P1 and P2. A low mean (<5 Lux) and maximal light level were measured during both P1 and P2. The implementation of guidelines lowered mean light disturbance intensity with a greater variability of light during P2. All noise levels were high and corresponded more to a quiet office for noise level equivalents and to a busy restaurant for peak noise levels during both P1 and P2. Guidelines decreased the noise level equivalent (P1, 51.3 dB; P2, 48.3 dB), peak noise level (P1, 74.9 dB; P2, 70.8 dB), and the number of acoustic identified alarms (P1, 22.1 dB; P2, 15.8 dB) during P2. CONCLUSION: The night light levels were low during both periods, and lowering the light levels induced a greater variation of light, which may impair sleep quality. All measured noise levels were high during both periods, which could contribute to sleep disturbance, and the implementation of guidelines significantly lowers some important noise levels. The background noise level was unchanged.