Medical Intensive Care Unit Population Research Articles

Abstract 15759: Utility of the Sofa Score to Risk Stratify Patients in the Cardiac Intensive Care Unit at a Tertiary Care Center

Introduction: The Sequential Organ Failure Assessment (SOFA) score predicts intensive care unit (ICU) mortality within a medical ICU population but utility of the SOFA score in the contemporary cardiac ICU (CICU) is unclear. Methods: Data from consecutive patients with primary cardiac (PC) and non-cardiac (PNC) disease admitted to the CICU at a tertiary care center from 1/1/19-2/28/19 and 10/1/19-11/30/19 were collected and analyzed by retrospective chart review, including demographics, comorbidities, primary reasons for admission, labs and SOFA score parameters. Patients were grouped into three categories based on their highest SOFA score within the first 24 hours of CICU admission: SOFA Score ≤ 6, 7-11 and ≥ 12. CICU and in-hospital mortality rates (adjusted for age, gender, race, and comorbidities) were compared using multivariate linear regression. Results: Of the 453 patients admitted to the CICU during the studied time period, 321 had PC diagnoses and 132 PNC diagnoses. The mean age was 63.5 and 59.6 ( p< 0.05) , 65.1% and 50.7% were male ( p< 0.05) , and 53.6% and 62.9% were white ( p=0.07) , and 70.4% and 56.8% had at least three or more comorbidities ( p<0.05) for the PC and PNC cohorts, respectively. The top three comorbidities were hypertension (70%), heart failure (39%), and diabetes mellitus (36%) for the PC group and hypertension (60%), diabetes mellitus (33%), and pulmonary disease (26%) for the PNC group, respectively. Increasing SOFA scores were associated with increased CICU and in-hospital mortality (Table) for patients with both PC and PNC diagnoses. Conclusion: Increased SOFA scores were associated with higher risk of CICU and in-hospital mortality. The SOFA score may be useful for risk stratification of CICU patients with both primary cardiac and non-cardiac diagnoses.

DIAGNOSTIC ACCURACY OF 4TS SCORE COMPARED TO HEPARIN-INDUCED THROMBOCYTOPENIA EXPERT PROBABILITY SCORE FOR IDENTIFYING HEPARIN-INDUCED THROMBOCYTOPENIA IN A MEDICAL ICU

SESSION TITLE: Tuesday Abstract Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/22/2019 01:00 PM - 02:00 PM PURPOSE: Heparin-induced thrombocytopenia (HIT) is challenging to diagnose in critically ill patients due to a higher incidence of acute thrombocytopenia. Underdiagnosis of HIT is potentially fatal, but overdiagnosis leads to unnecessary exposure to non-heparin anticoagulation. The 4Ts score was developed to aid in diagnosis but has limitations in the intensive care unit (ICU). The HIT expert probability (HEP) score is an alternative scoring system shown to have increased diagnostic accuracy in ICU patients in a subgroup analysis. We aim to validate these findings in a purely medical ICU. METHODS: 4Ts and HEP scores were retrospectively calculated for 91 patients with suspected HIT seen in an academic, tertiary care center medical ICU between January 2017 and April 2018. All patients had serotonin release assays (SRA) ordered. SRA positivity was used as the gold standard for HIT diagnosis. Scorers were blinded to both SRA and calculated results of the alternate scoring system. 4Ts scores equal to or greater than four and HEP scores equal to or greater than three represented positive scores. Sensitivity, specificity and likelihood ratios were calculated. McNemar’s test was used to evaluate differences in score results, sensitives and specificities. For significant differences, 95% confidence intervals were calculated using the Wald method. All statistical analyses used a significance level of 0.05. RESULTS: Three of our 91 patients had positive SRAs. The 4Ts score had a sensitivity of 0.67 (0.09-0.99), specificity of 0.45 (0.35-0.56) and a positive likelihood ratio (LR+) of 1.22 (0.54-2.78). The HEP score had a sensitivity of 1.00 (0.29-1.00), specificity of 0.69 (0.59-0.79) and a LR+ of 3.26 (2.83-4.46). Receiver operative characteristic (ROC) curve could not be created due to the low number of positive HIT cases. CONCLUSIONS: The accuracy measures of the HEP score were superior to the 4Ts score among medical ICU patients. The study was limited by single center status, small sample size of true positive HIT, retrospective design and having less experienced physicians conducting scoring, which has been suggested to favor HEP scoring in a previous study. Future studies continuing to look at this population are needed. CLINICAL IMPLICATIONS: The HEP score may have better diagnostic accuracy for HIT than the 4Ts score in the medical ICU population. DISCLOSURES: No relevant relationships by Thomas Iden, source=Web Response No relevant relationships by Audrey Jernigan, source=Web Response No relevant relationships by Markos Kashiouris, source=Web Response No relevant relationships by Victoria Okhomina, source=Web Response No relevant relationships by Xian Qiao, source=Web Response No relevant relationships by Kathleen Waybill, source=Web Response

Psychology consultation patterns in a medical intensive care unit: A brief report.

Intensive care unit (ICU) survivors frequently experience long-lasting mental health, cognitive, and physiologic challenges. Psychologists have a role in providing interventions to reduce patient distress during critical illness and improve outcomes. There is limited data regarding psychology consultations in the ICU. This brief report characterizes psychology consultations in a medical intensive care unit (MICU) in an academic medical center. Psychology consultations were prospectively tracked, with patient-related data retrospectively collected and analyzed. A total of 79 consecutive psychology consultations occurred at mean of 8 ± 6 days after MICU admission. Reasons for consultation were patient emotional distress (56%), rehabilitation therapy engagement (24%), family engagement (13%), cognitive disturbance (4%), and pain (4%). Patient characteristics were: mean age 56 ± 15 years, 54% women, 53% White, and 34% with psychiatric comorbidity at MICU admission. Patients referred for consultation had a longer MICU length of stay than the total MICU population (12 ± 9 days vs. 4 ± 6 days, p < .01). For consultations for emotional distress compared with limited rehabilitation therapy engagement, patient demographic characteristics were similar, with the exception of women (vs. men) being more commonly consulted for emotional distress (64 vs. 26%, p = .01). Patients with a longer MICU stay more commonly had a rehabilitation psychology consultation request, typically to provide support for emotional distress or engagement in rehabilitation therapy. Future research should evaluate the effectiveness of psychology interventions in the ICU. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Predisposed to failure? The challenge of rescue in the medical intensive care unit.

Medical intensive care unit (MICU) patients develop acute surgical processes that require operative intervention. There are limited data addressing outcomes of emergency general surgery (EGS) in this population. The aim of our study was to characterize the breadth of surgical consults from the MICU and assess mortality after abdominal EGS cases. All MICU patients with an EGS consult in an academic medical center between January 2010 and 2016 were identified from an electronic medical record-based registry. Charts were reviewed to determine reason for consult, procedures performed, and to obtain additional clinical data. A multivariate logistic regression was used to determine patient factors associated with patient mortality. Of 911 MICU patients seen by our service, 411(45%) required operative intervention, with 186 patients undergoing an abdominal operation. The postoperative mortality rate after abdominal operations was 37% (69/186), significantly higher than the mortality of 16% (1833/11192) for all patients admitted to the MICU over the same period (p < 0.05). Damage-control procedures were performed in 64 (34%) patients, with 46% mortality in this group. The most common procedures were bowel resections, with mortality of 42% (28/66) and procedures for severe clostridium difficile, mortality of 38% (9/24). Twenty-seven patients met our definition of surgical rescue, requiring intervention for complications of prior procedures, with mortality of 48%. Need for surgical rescue was associated with increased admission mortality (odds ratio, 13.07; 95% confidence interval, 2.86-59.77). Twenty-six patients had pathology amenable to surgical intervention but did not undergo operation, with 100% mortality. In patients with abdominal pathology at the time of operation, in-hospital delay was associated with increased mortality (odds ratio, 5.13; 95% confidence interval, 1.11-23.77). Twenty percent of EGS consults from the MICU had an abdominal process requiring an operative intervention. While the MICU population as a whole has a high baseline mortality, patients requiring abdominal surgical intervention are an even higher risk. Prognostic and epidemiological, level III.

The predictive performances of equations used to estimate unbound phenytoin concentrations in a medical ICU population and the impact of exogenous albumin administration

PurposeThis study evaluated the predictive performances of four equations (Sheiner-Tozer [ST], Kane-modified ST, Anderson-modified ST, and Cheng-modified ST) used to estimate free phenytoin concentrations in a medical intensive care unit (MICU) and assessed the impact of exogenously administered albumin. MethodsThirty MICU subjects receiving phenytoin were retrospectively evaluated. Predictive performances were assessed by mean absolute error (MAE), mean prediction error (MPE), and root mean squared error (RMSE); linear regression of predicted vs. actual unbound concentrations; and Bland-Altman plots. Parameters were further delineated by recent exogenous albumin administration. ResultsThe measured unbound phenytoin concentration was 2.14±0.84μg/mL for all 90 levels, 1.89±0.92μg/mL for the 58 levels without albumin, and 2.58±0.83μg/mL (p<0.0001 vs. without albumin) for the 32 levels after exogenous albumin. R2 values were below 0.4 for all equations. The ST equation over-predicted unbound concentrations whereas all other equations under-estimated unbound concentrations. All equations possessed bias and lacked precision. Bland-Altman plots demonstrated greatest bias with the ST equation. Albumin administration introduced additional bias, limited precision, reduced R2 values, and completely negated the performances of the ST and Kane-modified ST equations. ConclusionEstimating unbound concentrations with equations in the MICU population is discouraged.

Does Obesity Predispose Medical Intensive Care Unit Patients to Venous Thromboembolism despite Prophylaxis? A Retrospective Chart Review.

Background. Obesity is a significant issue in the critically ill population. There is little evidence directing the dosing of venous thromboembolism (VTE) prophylaxis within this population. We aimed to determine whether obesity predisposes medical intensive care unit patients to venous thromboembolism despite standard chemoprophylaxis with 5000 international units of subcutaneous heparin three times daily. Results. We found a 60% increased risk of venous thromboembolism in the body mass index (BMI) ≥ 30 kg/m2 group compared to the BMI < 30 kg/m2 group; however, this difference did not reach statistical significance. After further utilizing our risk model, neither obesity nor mechanical ventilation reached statistical significance; however, vasopressor administration was associated with a threefold risk. Conclusions. We can conclude that obesity did increase the rate of VTE, but not to a statistically significant level in this single center medical intensive care unit population.

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Introduction: New-onset atrial fibrillation (AF) has been associated with increased morbidity and mortality in surgical populations. Outcomes of patients with new-onset AF in the medical intensive care unit (ICU) are largely unknown. Hypothesis: To characterize morbidity and mortality in patients with new-onset, chronic, and no prior history of AF to better determine the effect of AF in a medical ICU population. Methods: Retrospective database review at University of Chicago Medical Center, a 596-bed university-affiliated teaching hospital with a 16-bed medical ICU. Patients were included if they were admitted to the ICU for >24 hours and were >18 years of age between June 1, 2008 and June 30, 2010. Exclusions included history of cardiothoracic surgery 90 days prior to admission or incomplete patient data. Primary outcome was 60-day mortality. Secondary outcomes included in-hospital mortality, ICU and hospital length of stay, and ICU and hospital costs. Chi-square and Fischer’s exact test for nominal data and student’s t-test for continuous variables were used for data analysis. Cox regression was utilized for multivariate analysis and Kaplan-Meier survival curves for time to mortality. Forward, step-wise logistic regression was used to evaluate confounding variables. Results: Of the 870 patients included in analysis, 701 had no AF, 53 experienced new-onset AF, and 116 had pre-existing AF. Pre-existing AF patients were separated into rapid ventricular response (RVR) (n=20) or no RVR (n=96). Patients with new-onset and pre-existing AF with RVR had significantly higher mortality than those who did not (50.9% vs. 65% vs. 25.2%, respectively; p<0.001 for all). In-hospital mortality was also significantly higher in new-onset and pre-existing AF with RVR compared to those with no history (45.3% vs. 35% vs. 18.1%; p<0.001 for all). Total hospital costs were higher and both ICU and hospital length of stay were significantly increased for patients with new-onset and pre-existing AF with RVR (p<0.001 for all). Conclusions: Medical ICU patients who develop new-onset AF or have pre-existing AF with an episode of RVR during ICU admission may experience higher mortality and morbidity than those with no prior history of AF.

Doppler‐Defined Pulmonary Hypertension in Medical Intensive Care Unit Patients: Retrospective Investigation of Risk Factors and Impact on Mortality

Pulmonary hypertension (PH) is poorly characterized in the critically ill. No prior studies describe the burden of or outcomes associated with PH in a general medical intensive care unit population. We hypothesize that PH is an important comorbidity prevalent in the modern medical intensive care unit. We undertook a preliminary investigation to define the consequences of Doppler-defined PH in the critically ill. A single-center retrospective case–control study of medical intensive care patients admitted over a 1-year period was conducted. Eligible patients had an echocardiogram within 4 days of admission. PH was defined to include both pulmonary arterial and venous hypertension and required a tricuspid regurgitant jet velocity ≥3 m/sec. Cases and controls were compared for comorbidities, illness severity, diagnoses, and mortality. Multivariable regression was performed to identify clinical features associated with PH and mortality. 299 (21% of admissions) patients had an eligible echocardiogram. Patients with PH (N=126) had a higher unadjusted mortality than did controls (N=173) (37% vs. 25%, P=0.04) and PH remained significantly associated with mortality after controlling for other clinical factors (HR=1.59, 95% CI=1.03–2.44, P=0.036). Low ejection fraction (OR=2.21, 95% CI=1.19–4.11, P=0.012) and pulmonary embolism (OR=4.28, 95% CI=1.59–11.5, P=0.004) were independently associated with PH. Doppler-defined PH is associated with mortality in the critically ill. Prospective studies are needed to define the prevalence of pulmonary venous hypertension versus pulmonary arterial hypertension, and the clinical consequences of each, in a general medical intensive care unit population.

Hypoxic hepatitis – epidemiology, pathophysiology and clinical management

Hypoxic hepatitis (HH), also known as ischemic hepatitis or shock liver, is characterized by centrilobular liver cell necrosis and sharply increasing serum aminotransferase levels in a clinical setting of cardiac, circulatory or respiratory failure. Nowadays it is recognized as the most frequent cause of acute liver injury with a reported prevalence of up to 10% in the intensive care unit. Patients with HH and vasopressor therapy have a significantly increased mortality risk in the medical intensive care unit population. The main underlying conditions contributing to HH are low cardiac output and septic shock, although a multifactorial etiology is found in the majority of patients. HH causes several complications such as spontaneous hypoglycemia, respiratory insufficiency due to the hepatopulmonary syndrome, and hyperammonemia. HH reverses after successful treatment of the basic HH-causing disease. No specific therapies improving the hepatic function in patients with HH are currently established. Early recognition of HH and its underlying diseases and subsequent initiation of therapy is of central prognostic importance. The purpose of this review is to provide an update on the epidemiology, pathophysiology, and diagnostic and therapeutic options of HH.

The Effect of Strict Blood Glucose Control on Biliary Sludge and Cholestasis in Critically Ill Patients

Cholestatic liver dysfunction and biliary sludge are common problems in critically ill patients. No specific strategies have been described to prevent cholestasis and biliary sludge in the intensive care unit (ICU). We examined liver dysfunction and biliary sludge prospectively in a large medical long-stay ICU population and hypothesized that tight glycemic control with intensive insulin therapy (IIT) reduces cholestasis and biliary sludge. This study was a preplanned subanalysis of 658 long-stay (at least a fifth day) ICU patients out of a large randomized controlled trial (n = 1200), studying the effects of IIT on the outcome of medical critical illness. Patients were allocated to either IIT (glycemia 80-110 mg/dl) or conventional insulin therapy (CIT) requiring insulin above a glycemia of 215 mg/dl. Different patterns of liver dysfunction were studied based on daily blood sample analysis, and biliary sludge was evaluated by ultrasonography. On admission, cholestasis was present in 17% of patients (n = 649), increasing to 20% on d 10 (n = 347), whereas ischemic hepatitis decreased from 3.4% (n = 588) to less than 1% (n = 328). IIT significantly decreased biliary sludge on d 5 (50.4 vs. 66.4%, P = 0.01; n = 250). The difference did not remain significant on d 10 (57.4 vs. 66.2%, P = 0.29; n = 136). IIT also lowered the cumulative risk of cholestasis (P = 0.03). Cholestatic liver dysfunction and biliary sludge are very common during prolonged critical illness but are significantly reduced by IIT.

Trauma and Acute Respiratory Distress Syndrome

Trauma and Acute Respiratory Distress Syndrome

Presence of electroencephalogram burst suppression in sedated, critically ill patients is associated with increased mortality.

This study investigates the possibility of a relationship between oversedation and mortality in mechanically ventilated patients. The presence of burst suppression, a pattern of severely decreased brain wave activity on the electroencephalogram, may be unintentionally induced by heavy doses of sedatives. Burst suppression has never been studied as a potential risk factor for death in patients without a known neurologic disorder or injury. Post hoc analysis of a prospectively observational cohort study. Medical intensive care units of a tertiary care, university-based medical center. A total of 125 mechanically ventilated, adult, critically ill patients. A validated arousal scale (Richmond Agitation-Sedation Scale) was used to measure sedation level, and the bispectral index monitor was used to capture electroencephalogram data. Burst suppression occurred in 49 of 125 patients (39%). For analysis, the patients were divided into those with burst suppression (49 of 125, 39%) and those without burst suppression (76 of 125, 61%). All baseline variables were similar between the two groups, with the overall cohort demonstrating a high severity of illness (Acute Physiology and Chronic Health Evaluation II scores of 27.4 +/- 8.2) and 98% receiving sedation. Of those with burst suppression, 29 of 49 (59%) died within 6 months compared with 25 of 76 (33%) who did not demonstrate burst suppression. Using time-dependent Cox regression to adjust for clinically important covariates (age, Charlson comorbidity score, baseline dementia, Acute Physiology and Chronic Health Evaluation II, Sequential Organ Failure Assessment, coma, and delirium), patients who experienced burst suppression were found to have a statistically significant higher 6-month mortality [Hazard's ratio = 2.04, 95% confidence interval, 1.12-3.70, p = 0.02]. The presence of burst suppression, which was unexpectedly high in this medical intensive care unit population, was an independent predictor of increased risk of death at 6 months. This association should be studied prospectively on a larger scale in mechanically ventilated, critically ill patients.

Suboptimal Aminoglycoside Dosing in Critically Ill Patients

Maximal aminoglycoside (AG) killing requires that the ratio of peak serum concentrations (Cmax) to the minimum inhibitory concentration (MIC) of the pathogen exceeds by > or =10. This has been shown to hasten resolution of infection in the general patient population. It was postulated that critically ill patients, likely to have larger intravascular volumes, are underdosed. The primary aim was to determine Cmax to MIC target attainment rate in medical intensive care unit (MICU) patients. A retrospective review of MICU patients who received at least 1 intravenous dose and serum concentration of either gentamicin or tobramycin was performed. A population pharmacokinetic model was developed, and MIC distributions for AG were used in determining the Cmax/MIC and in calculating the probability of attaining the pharmacodynamic (PD) target. One hundred two unique patients with 211 AG concentrations were analyzed to determine population pharmacokinetic parameters. Mean maximum clearance (CL) was 3.14L/h (95% confidence interval: 1.26-4.54 L/h), and mean volume of distribution (V) was 53 L (95% confidence interval: 38-66.8 L/h). Glomerular filtration rate and standardized body weight were identified as significant covariates for clearance in the final model. Standardized body weight also significantly affected V. There was only a 20% and 40% probability that patients receiving 7 mg/kg of gentamicin and tobramycin, respectively, will achieve PD target over the range of MIC distributions. Based on these data, the majority of critically ill patients would not be predicted to achieve the PD target under current dosing regimens. This may be a result of intensive care unit patients having a larger volume of distribution than reported in the literature. Future recommendations for treating gram-negative infections in the MICU population include using initial doses of 7 mg/kg of either gentamicin or tobramycin, measuring Cmax after the first dose, and determining MIC for the pathogen(s) with adjustment of subsequent doses to achieve the PD target.

Do proton-pump inhibitors increase the risk for nosocomial pneumonia in a medical intensive care unit?

Purpose The aim of this study was to determine whether the use of gastric acid-suppressive agents increases the risk of nosocomial pneumonia (NP) in a medical intensive care unit population. Materials and Methods Retrospective cohort study in a medical intensive care unit of a 554-bed, university-affiliated, academic medical center. Results A total of 924 medical records were included in the database during the study period of which 787 patients were included in the study. Out of this cohort,104 patients (13.2%) eventually developed a NP. The risk for patients who received proton-pump inhibitors (adjusted hazard ratio [AHR] 0.63; 95% CI 0.39-1.01) was not significantly different than in non exposed patients. Variables most strongly associated with NP were the administration of sedatives or neuromuscular blockers for at least 2 consecutive days (AHR 3.39;95% CI 1.99-5.75), an Acute Physiology and Chronic Health Evaluation II (APACHE II) severity score greater than 15 (AHR, 3.34; 95% CI 1.82-6.50), and presence of a central venous catheter (AHR, 1.76; 95% CI 1.12-2.76). Conclusions Prior use of a proton-pump inhibitor did not correlate with a significant increase in the risk of developing NP. This risk was higher with the administration of sedatives or neuromuscular blockers, increased disease severity, and placement of a central venous catheter.

Glucose Measurement: Confounding Issues in Setting Targets for Inpatient Management

Van den Berghe et al. (1) reported a significant reduction in mortality with normoglycemia (target value 80–110 mg/dl) in patients whose medical intensive care unit (ICU) stay was >72 h and reduced morbidity in all patients, regardless of the duration of ICU stay. Although severe hypoglycemia did not occur in the Van den Berghe et al. study, 18.7% of patients in the intensive treatment group compared with 3.1% of those who received conventional therapy did experience hypoglycemia (defined as glucose <40 mg/dl), albeit with no adverse consequences reported. However, altered consciousness is common in the ICU, and even severe hypoglycemia may be unrecognized. Other studies (2,3) examining intensive insulin protocols in various inpatient settings have suggested benefits in clinical outcomes associated with improved glycemic control. In a mixed ICU population, Van den Berghe et al. (2) previously demonstrated reduced morbidity and mortality with three- to fourfold less hypoglycemia than the medical ICU population (2). Thus, careful assessment of glucose measurement and how it may impact the targets selected in the hospital are critical safety issues in intensive management of hyperglycemia. As a result of increasing evidence that tight glycemic control is beneficial in the management of inpatients with diabetes, the American Diabetes Association (ADA) currently recommends a glucose target “as close to 110 mg/dl as possible and generally <180 mg/dl” for critically ill patients (4). The American Association of Clinical Endocrinologists recommends the “upper limits for glycemic targets” of 110 mg/dl in critically ill patients (5). In practice, it may be difficult to obtain the level of glycemic control (average glucose 111 mg/dl in the intensively managed group) achieved by Van den Berghe et al. Though a wider range of glucose values has been targeted, rarely have mean glucose values between 80 and 110 mg/dl been achieved, …

The effect of emergency department delay on outcome in critically ill medical patients: evaluation using hospital mortality and quality of life at 6 months

To assess the impact of delay in emergency department (ED) on outcome of critically ill patients admitted to the medical intensive care unit (MICU). Outcome was defined as hospital mortality and as health-related quality of life (HRQoL) at 6 months after intensive care assessed by the 15D measure. The 15D is a generic, 15-dimensional, standardized measure of HRQoL. We hypothesized that prolonged stay in the ED is related to worse outcome. A prospective follow-up cohort study in university hospital. All consecutive 1675 patients admitted to the MICU between July 2002 and June 2004. The 15D questionnaire was mailed to all patients alive at 6 months after admission. Of all MICU patients, 64% were admitted from ED. The mean length of stay in the ED was 6.2 h (95%CI 5.9-6.5 h). The hospital mortality rate was 24.4% (20.0% in the ED vs. 33.0% in the non-ED cohort, P < 0.001) and it was associated with higher age and degree of physiological derangement at admission. Neither the length of ED stay was associated with hospital mortality (P = 0.82) nor with HRQoL at 6 months after MICU admission (P = 0.34). Altogether, HRQoL at 6 months was significantly lower compared with the age- and sex-matched general population (P < 0.001). In a university hospital, the length of ED stay was not associated with the outcome of critically ill medical patients. However, we feel that the effect of ED treatment and delay on outcome and outcome prediction in the critically ill patients deserves further evaluation.

Comparison of Premortem Clinical Diagnoses in Critically Ill Patients and Subsequent Autopsy Findings

To determine whether our practice of requesting an autopsy for patients who die in the medical intensive care unit (MICU) continues to be a valid approach to obtain clinically and educationally relevant findings. In this retrospective study conducted in an adult MICU population of a university hospital, the clinical diagnoses and postmortem major diagnoses of 100 patients who died in 1996 (autopsy rate of 93%) were compared. Eighty-one percent of the clinical diagnoses were confirmed at autopsy. In 16%, autopsy findings revealed a major diagnosis that, if known before death, might have led to a change in therapy and prolonged survival (class I missed major diagnoses). The most frequent class I missed major diagnoses were fungal infection, cardiac tamponade, abdominal hemorrhage, and myocardial infarction. Another 10% of autopsies revealed a diagnosis that, if known before death, would probably not have led to a change in therapy (class II error). Autopsy remains an important tool for education and quality control. In contrast with historical series of 1 to 2 decades ago, there is a clear shift in the type of class I missed major diagnoses toward opportunistic infections. Bedside-applicable techniques such as electrocardiography with supplemental posterior leads, echocardiography, and meticulous abdominal ultrasonography might improve the outcome in selected MICU patients.

Assessing the Need for Reintubation: A Prospective Evaluation of Unplanned Endotracheal Extubation

Unplanned endotracheal extubation (UEE) is a common complication in medical intensive care units but very little data about UEE in surgical populations are available. Our hypothesis is that the surgical intensive care unit (SICU) population requires reintubation less frequently compared with the medical intensive care unit population. We prospectively gathered data on patients in a SICU in an attempt to identify the incidence of UEE and to study the need for reintubation after UEE. During an 18-month period, we prospectively identified SICU patients from a quality improvement database who required ventilatory support. All patients who self-extubated were included in the study. Fifty-eight of 1,178 intubated patients experienced unplanned extubation 61 times during the 18-month period. A total of 22 patients (36%) required reintubation, whereas 39 patients (64%) did not. Thirty-three patients self-extubated while being actively weaned from ventilatory support. Of these, only 5 patients (15%) required reintubation and 28 patients (85%) did not (p < 0.01). A total of 85% of patients who self-extubate during the weaning process did not require reintubation in our study. Those who have an FiO2 >50%, a lower PaO2/FiO2 ratio, had UEE occur by accident, or were not being weaned when UEE occurred required reintubation more frequently. These data suggest that some of our SICU patients are intubated longer than necessary, which may translate into more ventilator related complications, longer ICU stays and increased cost.

Rapid Correction of Hypokalemia Using Concentrated Intravenous Potassium Chloride Infusions

There are conflicting recommendations regarding the use of intravenous potassium chloride infusions for acute correction of hypokalemia. We examined the effects of 495 sets of potassium chloride infusions administered to a medical intensive care unit population. The infusion sets consisted of one to eight consecutive individual infusions, each containing 20 mEq of potassium chloride in 100 mL of saline administered. The mean preinfusion potassium level was 3.2 mmol/L, and the mean postinfusion potassium level was 3.9 mmol/L. The mean increment in serum potassium level per 20-mEq infusion was 0.25 mmol/L. No temporally related life-threatening arrhythmias were noted; however, there were 10 instances of mild hyperkalemia. Our data endorse the relative safety of using concentrated (200-mEq/L) potassium chloride infusions at a rate of 20 mEq/h via central or peripheral vein to correct hypokalemia in patients in the intensive care unit.