Prediction of extubation failure in medical intensive care unit patients.

PURPOSE: The purpose of this study was to evaluate prediction factors for extubation failure (need for reintubation within 48 hours) in medical intensive care unit patients. MATERIALS AND METHODS: Sixty-one patients extubated after mechanical ventilation for more than 48 hours were included in the study. A retrospective analysis of medical records and a prospectively maintained database on respiratory parameters was conducted. RESULTS: Low serum anion gap (P = .001), low serum anion gap corrected for serum albumin (P = .010), and low arterial partial pressure of oxygen (Pao(2))/fraction of inspired oxygen (Fio(2)) ratio (P = .032) were significantly associated with extubation failure. Binary logistic regression analysis revealed low uncorrected and corrected serum anion gap (P = .006 and P = .025, respectively; odds ratio, 0.59 for both) and low Pao(2)/Fio(2) ratio (P = .038; odds ratio, 0.99) as risk factors for extubation failure. Regarding extubation failure, receiver operating characteristic curve (ROC) analysis demonstrated good predictive capabilities of serum anion gap (ROC area under the curve, 0.835; P = .004; cutoff, 7.7 mEq/L; sensitivity, 70.4%; specificity, 85.7%) and corrected serum anion gap (ROC area under the curve, 0.808; P = .009; cutoff, 8.8 mEq/L; sensitivity, 87.5%; specificity, 71.4%). A significantly higher risk for extubation failure was observed in patients with serum anion gap 5.2 mEq/L or less (relative risk, 8.8; 95% confidence interval, 2.4-32.4; P = .004) and corrected serum anion gap 8.6 mEq/L or less (relative risk, 10.0; 95% confidence interval, 2.2-44.9; P = .004). CONCLUSIONS: Low preextubation serum anion gap values and low preextubation Pao(2)/Fio(2) ratio might help to predict extubation failure in medical intensive care unit patients.

Amanita poisonings resulting in acute, reversible renal failure: new cases, new toxic Amanita mushrooms.

BACKGROUND: Renal failure as a consequence of eating mushrooms has been reported repeatedly after ingestion of webcaps of the Cortinarius orellanus group. But mushrooms of the genus Amanita can also cause renal failure: Amanita smithiana (North America) and Amanita proxima (Mediterranean area). Here, we discuss poisonings caused by other white amanitas. A German and--independently--two Portuguese patients reported the ingestion of completely white mushrooms with ring. Similar to intoxications with A. smithiana or A. proxima, the clinical picture was characterized by nausea and vomiting 10-12 h after ingestion, severe acute renal failure and mild hepatitis. Renal biopsy showed acute interstitial nephritis and tubular necrosis. Two patients were given temporary haemodialysis. All have fully recovered their renal function. Poisonings caused by mushrooms containing the toxin of A. smithiana were suspected. We tested 20 Amanita species for the presence of this toxin. METHODS: Thin layer chromatography was applied to detect A. smithiana nephrotoxin in herbarium specimens using authentic material of A. smithiana as reference. RESULTS: A. smithiana toxin could be detected in Amanita boudieri, Amanita gracilior and in Amanita echinocephala. A. boudieri was collected by the Portuguese patients. A. echinocephala is the only nephrotoxic Amanita growing North of the Alps and is suspected to be the cause of renal failure in the German patient. No A. smithiana toxin was detectable in the nephrotoxic A. proxima. CONCLUSIONS: A. boudieri, A. gracilior and A. echinocephala are nephrotoxic. These intoxications are clinically similar to that of A. smithiana, with acute reversible renal failure and mild hepatitis but are different in their clinical picture from Orellanus syndrome characterized by a delayed onset of severe and often irreversible renal failure.

Risk assessment of moderate to severe alcohol withdrawal--predictors for seizures and delirium tremens in the course of withdrawal.

AIMS: To develop a prediction model for withdrawal seizures (WS) and delirium tremens (DT) during moderate to severe alcohol withdrawal syndrome (AWS) in a large cohort of inpatients treated for AWS (n = 827). METHODS: Re-analysis of a cohort study population treated between 2000 and 2009. All patients received a score-guided and symptom-triggered therapy for AWS. Multivariable binary logistic regression models with stepwise variable selection procedures were conducted providing odds ratio (OR) estimates. RESULTS: In the multivariable regression, significant predictors of WS during AWS therapy were a delayed climax of withdrawal severity since admission [OR/10 h: 1.23; 95% confidence interval (CI): 1.1-1.4; P < 0.001)], prevalence of structural brain lesions in the patient's history (OR 6.5; 95% CI: 3.0-14.1; P < 0.001) and WS as the cause of admittance (OR 2.6; 95% CI: 1.4-4.8; P = 0.002). Significant predictors at admission for the occurrence of DT were lower serum potassium (OR/1 mmol/l 0.33; 95% CI: 0.17-0.65; P = 0.001), a lower platelet count (OR/100.000 0.42; 95% CI: 0.26-0.69; P = 0.001) and prevalence of structural brain lesions (OR 5.8; 95% CI: 2.6-12.9; P < 0.001). CONCLUSION: In this large retrospective cohort, some easily determinable parameters at admission may be useful to predict a complicated course of alcohol withdrawal regarding the occurrence of WS or DT. Using the provided nomograms, clinicians can estimate the percentage likelihood of patients to develop either WS or DT during their course of withdrawal. Prevalence of structural brain lesions in the patient's history does strongly warrant a careful observation of patients.

Carbamazepine and valproate as adjuncts in the treatment of alcohol withdrawal syndrome: a retrospective cohort study.

AIMS: To compare the clinical course, incidence of withdrawal seizures (WS) or delirium tremens (DT) and side effects during treatment of alcohol withdrawal in patients treated with either carbamazepine (CBZ) or valproate (VPA) as an adjunct to clomethiazole and clonidine therapy. METHODS: Retrospective analysis of charts of two cohorts of inpatients treated during 2000-2009: CBZ 374 patients, VPA 453 patients. RESULTS: At baseline, those treated with VPA and those treated with CBZ were similar except for a trend to younger age and a higher incidence of previous WS in the CBZ group. The median duration of pharmacological treatment (91 vs. 76 h; P < 0.001) and the length of stay (8 vs. 6 days; P < 0.001) as well as the need for intensive care treatment (7 vs. 2%; P = 0.001) were significantly higher in the CBZ than the VPA group. Additionally, withdrawal-related complications such as WS occurred more often in the CBZ group (9.6 vs. 5.5%; not significant after adjusting for potential confounders); the incidence of DT in the CBZ group was insignificantly higher (6.6 vs. 4.4%; P = 0.52). Admittance with seizures and older age were predictors of WS and DT, respectively. Adverse drug reactions, mainly affecting the central nervous system, were significantly more frequent with CBZ than VPA (7.6 vs. 2%; P < 0.001). CONCLUSION: During alcohol withdrawal, VPA may offer some benefits compared with CBZ due to favorable tolerability, possibly less incidence of WS and a shorter duration of pharmacological treatment.

Risk assessment of severe tricyclic antidepressant overdose.

Prognostic factors for severe complications in tricyclic antidepressant (TCA) overdose remain unclear. We therefore evaluated the value of clinical characteristics and electrocardiograph (ECG) parameters to predict serious events (seizures, arrhythmia, death) in severe TCA overdose of 100 patients using logistic regression models for risk assessment. The overall fatality rate was 6%, arrhythmia occurred in 21% and 31% of the patients developed seizures. Using an univariable logistic regression model, the maximal QRS interval (OR 1.22; 95% CI 1.06-1.41; p = .005), the time lag between ingestion and occurrence of first symptoms of overdose (OR 1.13; 95% CI 0.99-1.29; p = .072) and the age (OR 0.73; 95% CI 0.55-0.98; p = .038) were determined as the solely predictive parameters. In the multivariable logistic regression model, the QRS interval could not be established as independent predictor, however, the terminal 40-ms frontal plane QRS vector (T40) reached statistical significance regarding prediction of serious events (odds ration [OR] 1.70; 95% confidence interval [CI] 1.02-2.84; p = .041), along with age and time lag between ingestion and onset of symptoms of overdose with a sensitivity and specificity of 71% and 70%, respectively. Evaluation of both clinical characteristics and ECG-parameters in the early stage of TCA overdose may help to identify those patients who urgently need further aggressive medical observation and management.

Treatment of severe intravenous phenytoin overdose with hemodialysis and hemoperfusion.

BACKGROUND: Phenytoin is a widely used anticonvulsant agent responsible for a number of intentional and unintentional overdoses. However, besides supportive care, specific treatment recommendations to enhance elimination of the parent compound have been discussed controversially and effectiveness of hemoperfusion is under debate. CASE REPORT: A women with a prehistory of cerebral seizures was presented following a severe iatrogenic phenytoin overdose with a peak plasma concentration of 117 mg/L. A Phenytoin overdose could be contributed to both inadequate dosing and missed repeated drug monitoring. Native phenytoin body clearance failed to relevantly lower phenytoin concentration. Thus, three sessions of a four-hour long combination of activated charcoal hemoperfusion and high-flux hemodialysis were performed resulting in considerably reduced half-life during these measures of about 7-13 hours compared to the native half-life wavering between 40-100 hours. This resulted in a substantial clinical improvement in terms of central nervous system toxicity. CONCLUSIONS: Hemodiaperfusion with activated charcoal seems to be a reasonable measure for forced lowering of highly toxic phenytoin plasma concentration and should be considered especially in circumstances following intravenous overdose (e.g. inadequate iatrogenic dosing). Its narrow therapeutic range enforces strictly adequate dosing and subsequent repeated drug monitoring of phenytoin.