Erin Frazee

Influence of dexmedetomidine therapy on the management of severe alcohol withdrawal syndrome in critically ill patients

PURPOSE Although benzodiazepines are first-line drugs for alcohol withdrawal syndrome (AWS), rapidly escalating doses may offer little additional benefit and increase complications. The purpose of this study was to evaluate dexmedetomidines impact on benzodiazepine requirements and hemodynamics in AWS. MATERIALS AND METHODS This retrospective case series evaluated 33 critically ill adults with a primary diagnosis of AWS from 2006 to 2012 at an academic medical center. RESULTS Dexmedetomidine began a median (interquartile range) of 11 (2, 32) hours into intensive care unit admission and was titrated to an infusion rate of 0.7 (0.4, 0.7) μg kg(-1) h(-1) to achieve the desired depth of sedation. In the 12 hours after dexmedetomidine began, patients experienced a 20-mg reduction in median cumulative benzodiazepine dose used (P < .001), a 14-mm Hg lower mean arterial pressure (P = .03), and a 17-beats/min reduction in median heart rate (P < .001). Four (12%) patients experienced hypotension (systolic blood pressure <80 mm Hg) during therapy, and there were no cases of bradycardia (heart rate <40 beats/min). CONCLUSION Dexmedetomidine decreased benzodiazepine requirements and improved the overall hemodynamic profile of patients with severe AWS. These results provide promising evidence about the potential benefit of dexmedetomidine for AWS.

Clostridium difficile infection: a multicenter study of epidemiology and outcomes in mechanically ventilated patients.

Objectives:Clostridium difficile is a leading cause of hospital-associated infection in the United States. The purpose of this study is to assess the prevalence of C. difficile infection among mechanically ventilated patients within the ICUs of three academic hospitals and secondarily describe the influence of C. difficile infection on the outcomes of these patients. Design:A retrospective cohort study. Setting:ICUs at three teaching hospitals: Barnes-Jewish Hospital, Mayo Clinic, and Creighton University Medical Center over a 2-year period. Patients:All hospitalized patients requiring mechanical ventilation for greater than 48 hours within an ICU were eligible for inclusion. Interventions:None. Measurements and Main Results:A total of 5,852 consecutive patients admitted to the ICU were included. Three hundred eighty-six (6.6%) patients with development of C. difficile infection while in the hospital (5.39 cases/1,000 patient days). Septic shock complicating C. difficile infection occurred in 34.7% of patients. Compared with patients without C. difficile infection (n = 5,466), patients with C. difficile infection had a similar hospital mortality rate (25.1% vs 26.3%, p = 0.638). Patients with C. difficile infection were significantly more likely to be discharged to a skilled nursing or rehabilitation facility (42.4% vs 31.9%, p < 0.001), and the median hospital (23 d vs 15 d, p < 0.001) and ICU length of stay (12 d vs 8 d, p < 0.001) were found to be significantly longer in patients with C. difficile infection. Conclusions:Clostridium difficile infection is a relatively common nosocomial infection in mechanically ventilated patients and is associated with prolonged length of hospital and ICU stay, and increased need for skilled nursing care or rehabilitation following hospital discharge.

Derivation of Urine Output Thresholds That Identify a Very High Risk of AKI in Patients with Septic Shock

BACKGROUND AND OBJECTIVES To promote early detection of AKI, recently proposed pretest probability models combine sub-Kidney Disease Improving Global Outcomes (KDIGO) AKI criteria with baseline AKI risk. The primary objective of this study was to determine sub-KDIGO thresholds that identify patients with septic shock at highest risk for AKI. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This was a retrospective analysis of 390 adult patients admitted to the medical intensive care unit (ICU) of a tertiary, academic medical center with septic shock between January 2008 and December 2010. Hourly urine output was collected from the time of septic shock recognition (hour 0) to hour 96, urine catheter removal, or ICU discharge (whichever occurred first). All available serum creatinine (SCr) measurements were collected until hour 96. The AKI pretest probability model was assessed during the first 12 hours of resuscitation and included the initial episode of oliguria, increase from baseline to peak SCr level, and Acute Physiology and Chronic Health Evaluation (APACHE) III score in a multivariable receiver-operator characteristic (ROC) analysis. The primary outcome was the incidence of stage II or III (stage II+) AKI defined by KDIGO criteria. Secondary outcomes included the need for RRT and 28-day mortality. RESULTS Ninety-eight (25%) patients developed stage II+ AKI after septic shock recognition. APACHE III score and increase in SCr level in the first 12 hours were not statistically associated with stage II+ AKI in multivariable ROC analysis. Consecutive oliguria for 3 hours had fair predictive ability for achieving stage II+ AKI criteria (area under ROC curve, 0.73; 95% confidence interval [95% CI], 0.68 to 0.78), and oliguria for 5 hours demonstrated optimal accuracy (82%; 95% CI, 79% to 86%). CONCLUSIONS Three to 5 hours of consecutive oliguria in patients with septic shock may provide a valuable measure of AKI risk. Further validation to support this finding is needed.

Adjunctive aerosolized colistin for multi-drug resistant gram-negative pneumonia in the critically ill: a retrospective study

BackgroundThe incidence of multi-drug resistant (MDR) gram-negative (GN) organisms including Pseudomonas and Acinetobacter spp has increased in the last decade, prompting re-evaluation of colistin for the management of these infections. Aerosolized colistin as an adjunct to intravenous therapy is a current option for the management of MDR-GN pneumonia, although data supporting this practice is limited. This study evaluates the efficacy of adjunctive aerosolized colistin in combination with intravenous colistin in critically ill patients with MDR-GN pneumonia.MethodsA retrospective multi-center cohort analysis comparing critically ill patients with MDR-GN pneumonia who received intravenous colistin (IV) alone or in combination with adjunctive aerosolized colistin (IV/AER) with a primary endpoint of clinical cure at the end of colistin therapy. Secondary endpoints included microbiologic cure, duration of mechanical ventilation, length of stay, and hospital mortality. A post-hoc subgroup analysis was performed for patients with high quality cultures used for diagnosis of MDR-GN pneumonia. Dichotomous data were compared using Fisher’s exact test while the student’s t-test or Mann–Whitney U test were used for continuous variables.ResultsNinety-five patients met criteria for evaluation with 51 patients receiving IV and 44 receiving IV/AER. Baseline characteristics were similar between the two groups. Twenty patients (39.2%) receiving IV and 24 (54.5%) receiving IV/AER achieved clinical cure (p = 0.135). There was no difference in microbiologic cure rates between the IV and IV/AER colistin groups (40.7vs. 44.4%, p = 0.805). The IV group demonstrated a trend towards higher pneumonia attributable mortality (70.4 vs. 40%, p = 0.055). In the subgroup analysis of patients with high quality respiratory cultures, there was a significantly lower clinical cure rate for those in the IV group as compared to the IV/AER group (31.3 vs. 57.1%, p = 0.033).ConclusionsAddition of aerosolized colistin to IV colistin may improve clinical cure and mortality for patients with MDR-GN pneumonia. Larger, prospective trials are warranted to confirm the benefit of adjunctive aerosolized colistin in critically ill patients with MDR-GN pneumonia.

Evaluating Muscle Mass by Using Markers of Kidney Function: Development of the Sarcopenia Index

Objectives: Sarcopenia is associated with a poor prognosis in the ICU. The purpose of this study was to describe a simple sarcopenia index using routinely available renal biomarkers and evaluate its association with muscle mass and patient outcomes. Design: A retrospective cohort study. Setting: A tertiary-care medical center. Patients: High-risk adult ICU patients from October 2008 to December 2010. Interventions: The gold standard for muscle mass was quantified with the paraspinal muscle surface area at the L4 vertebrae in the subset of individuals with an abdominal CT scan. Using Pearson’s correlation coefficient, serum creatinine-to-serum cystatin C ratio was found to be the best performer in the estimation of muscle mass. The relationship between sarcopenia index and hospital and 90-day mortality, and the length of mechanical ventilation was evaluated. Measurements and Main Results: Out of 226 enrolled patients, 123 (54%) were female, and 198 (87%) were white. Median (interquartile range) age, body mass index, and body surface area were 68 (57–77) years, 28 (24–34) kg/m2, and 1.9 (1.7–2.2) m2, respectively. The mean (± SD) Acute Physiology and Chronic Health Evaluation III was 70 (± 22). ICU, hospital, and 90-day mortality rates were 5%, 12%, and 20%, respectively. The correlation (r) between sarcopenia index and muscle mass was 0.62 and coefficient of determination (r 2) was 0.27 (p < 0.0001). After adjustment for Acute Physiology and Chronic Health Evaluation III, body surface area, and age, sarcopenia index was independently predictive of both hospital (p = 0.001) and 90-day mortality (p < 0.0001). Among the 131 patients on mechanical ventilator, the duration of mechanical ventilation was significantly lower on those with higher sarcopenia index (–1 d for each 10 unit of sarcopenia index [95% CI, –1.4 to –0.2; p = 0.006]). Conclusions: The sarcopenia index is a fair measure for muscle mass estimation among ICU patients and can modestly predict hospital and 90-day mortality among patients who do not have acute kidney injury at the time of measurement.

Effect of Continuous Venovenous Hemofiltration Dose on Achievement of Adequate Vancomycin Trough Concentrations

ABSTRACT The vancomycin dose necessary for the achievement of target serum trough concentrations during continuous venovenous hemofiltration (CVVH) remains to be elucidated. This was a retrospective cohort study of critically ill adults at a tertiary medical center on concurrent CVVH and vancomycin between 2006 and 2010 with a steady-state vancomycin trough concentration. The 87 included patients were grouped according to low (≤30 ml/kg/h; n = 10) or high (>30 ml/kg/h; n = 77) CVVH hemofiltration rate (HFR) for analysis. Vancomycin goal trough achievement occurred in only 32 (37%) patients. The primary endpoint of trough attainment significantly differed between HFR subgroups: 90% versus 30% in low- and high-HFR individuals, respectively (P < 0.001). Patients with subtherapeutic trough concentrations had a median (interquartile range) HFR of 40 ml/kg/h (range, 37 to 47 ml/kg/h) compared to 36 ml/kg/h (range, 30 to 39 ml/kg/h) in those who achieved the trough goal. Irrespective of goal trough, an inverse correlation existed between HFR and serum vancomycin concentration (r = −0.423; P < 0.001). In the subgroup of 14 methicillin-resistant Staphylococcus aureus (MRSA) patients, trough achievement was similar to the aggregate cohort (36%). Mortality at 28 days was unrelated to trough achievement in both the overall sample (P = 0.516) and in culture-positive MRSA patients (P = 0.396). Critically ill patients undergoing CVVH therapy may experience clinically significant reductions in goal vancomycin troughs. The results of the present study justify prospective evaluations in this population to determine the optimal vancomycin dosing strategy for attainment of goal trough concentrations.

Levetiracetam Pharmacokinetics in a Patient Receiving Continuous Venovenous Hemofiltration and Venoarterial Extracorporeal Membrane Oxygenation

Levetiracetam is a first‐line therapy for seizures in critically ill patients because of its clinical efficacy, minimal drug interactions, and wide therapeutic window. The primary mechanism of levetiracetam clearance is renal, and the drug has a low molecular weight. It is hydrophilic and exhibits minimal protein binding. Thus it is expected that levetiracetam will be removed by continuous venovenous hemofiltration (CVVH), with limited clearance by venoarterial extracorporeal membrane oxygenation (ECMO). We describe the case of a 67‐year‐old man who was admitted to the cardiovascular surgery intensive care unit after cardiac arrest and initiation of venoarterial ECMO. His course was complicated by multiorgan dysfunction including acute renal failure requiring CVVH. On hospital day 6, intravenous levetiracetam, at a loading dose of 2000 mg followed by a maintenance dose of 1000 mg every 12 hours, was initiated for new‐onset seizures. The volume of distribution was 0.65 L/kg, and clearance was measured with peak (ranging from 26.5–39.8 μg/ml) and trough (ranging from 13.9–18.2 μg/ml) concentrations. Elimination half‐life ranged from 8.7–10.1 hours. Renal dysfunction reduces levetiracetam clearance, and dosage reductions are recommended to prevent accumulation. Current CVVH dosing recommendations are based on predicted removal without clinical data. The volume of distribution and clearance in this case were similar to those of a normal healthy patient. Based on these results, we recommend considering an initial levetiracetam dose of 1000 mg every 12 hours for patients receiving CVVH, with dosage adjustments based on therapeutic drug monitoring.

Risk Factors for Dexmedetomidine-Associated Hemodynamic Instability in Noncardiac Intensive Care Unit Patients.

BACKGROUND:The reported incidence of hypotension and bradycardia in patients receiving dexmedetomidine for sedation commonly exceeds 50%. In this study, we describe the incidence of, patient- and treatment-specific risk factors for, and clinical significance of dexmedetomidine-associated hemodynamic instability. METHODS:This retrospective cohort study was conducted in critically ill adults receiving dexmedetomidine for sedation at Mayo Clinic Hospital in Rochester, MN, during a 1-year period. The primary end point was hemodynamic instability: a composite of hypotension and/or bradycardia, defined as systolic blood pressure <80 mm Hg, diastolic blood pressure <50 mm Hg, or heart rate <50 beats per minute during dexmedetomidine therapy. Cox proportional hazards models were constructed to determine hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk factors of hemodynamic instability. RESULTS:Hemodynamic instability occurred in 197 of the analyzed 300 patients receiving dexmedetomidine, resulting in a cumulative incidence of 71% at 24 hours via Kaplan-Meier estimation. In addition to dexmedetomidine, univariate analysis identified age, vasopressor use, low baseline arterial blood pressure, and concomitant sedatives as associated with increased risk of hemodynamic instability. Multivariable analysis demonstrated associations between age (HR, 1.23 per 10 years, 95% CI, 1.10–1.38) and low baseline blood pressure (HR, 2.42 at dexmedetomidine initiation, 95% CI, 1.68–3.49) and risk of hemodynamic instability. Variables such as concomitantly administered cardiac medications or sedative therapies and dexmedetomidine infusion rates >0.7 &mgr;g/kg/h were not found to be predictors of hemodynamic instability among the analyzed sample. CONCLUSIONS:Hemodynamic instability commonly occurs in critically ill adults receiving dexmedetomidine, with more than two thirds of this cohort experiencing hypotension and/or bradycardia within 24 hours of initiation. Increasing age and low baseline arterial blood pressure were associated with the development of hemodynamic instability. These findings suggest that clinicians should be aware of the potential risk of hemodynamic instability when using dexmedetomidine in patients with advanced age or low baseline arterial blood pressure.

Cystatin C–Guided Vancomycin Dosing in Critically Ill Patients: A Quality Improvement Project

BACKGROUND The aim of the study was to determine whether a vancomycin dosing algorithm based on estimated glomerular filtration rate from creatinine and cystatin C levels (eGFRcr-cys) improves target trough concentration achievement compared to an algorithm based on estimated creatinine clearance (eCLcr) in critically ill patients. STUDY DESIGN This prospective quality improvement project evaluated intensive care unit (ICU) patients started on intravenous vancomycin using one of 2 different strategies. Dosing regimens were selected and implemented after an individualized goal trough range was established (10-15 or 15-20mg/L). Steady-state goal trough achievement was compared between treatment arms with and without adjustment for potential confounders. SETTING & PARTICIPANTS 3 medical and surgical ICUs at a single tertiary medical center. QUALITY IMPROVEMENT PLAN During January 2012 to October 2013, vancomycin was dosed according to eCLcr using the Cockcroft-Gault formula (control arm). During December 2013 to May 2015, a multidisciplinary quality improvement team implemented a novel vancomycin dosing algorithm according to eGFRcr-cys using the CKD-EPI equation (intervention arm). OUTCOME Steady-state initial goal vancomycin trough concentration achievement. MEASUREMENTS & RESULTS More patients in the intervention arm (67 of 135 [50%]) achieved therapeutic trough vancomycin levels than in the control arm (74 of 264 [28%]; OR, 2.53; 95% CI, 1.65-3.90; P<0.001). Improved trough achievement was maintained even after adjustment for age, sex, APACHE (Acute Physiology and Chronic Health Evaluation) III score, fluid balance, baseline CLcr, surgical admission diagnosis, presence of sepsis, and goal trough concentration range (adjusted OR, 2.79; 95% CI, 1.76-4.44; P<0.001). Clinical outcomes were similar between groups. LIMITATIONS Nonrandomized, incomplete algorithm compliance. CONCLUSIONS A vancomycin dosing nomogram based on eGFRcr-cys significantly improved goal trough achievement compared to eCLcr among ICU patients with stable kidney function. Further studies are warranted to characterize the relationship between use of cystatin C-guided dosing and clinical outcomes.

Fluid Management for Critically Ill Patients: A Review of the Current State of Fluid Therapy in the Intensive Care Unit

Background: Intravenous fluids (IVF) are frequently utilized to restore intravascular volume in patients with distributive and hypovolemic shock. Although the benefits of the appropriate use of fluids in intensive care units (ICUs) and hospitals are well described, there is growing knowledge regarding the potential risks of volume overload and its impact on organ failure and mortality. To avoid volume overload and its associated complications, strategies to identify fluid responsiveness are developed and utilized more often among ICU patients. Apart from the amount of fluid utilized for resuscitation, the type of fluid used also impacts patient outcome. Colloids and crystalloids are two types of fluids that are utilized for resuscitation. The efficacy of each fluid type on the expansion of intravascular volume on one hand and the potential adverse effects of each individual fluid, on the other hand, need to be considered when choosing the type of fluid for resuscitation. The negative impact of hydroxyethyl starch on kidney function, of albumin on the mortality of head trauma patients and chloride-rich crystalloids on mortality and kidney function, are only examples of new developments in the field. Summary: In this paper, we will review the impact of fluid overload on patient outcomes, define the fluid challenge, describe the differences in static and dynamic estimates of fluid responsiveness, and review the effect of different types of fluid on patient outcome. Key Message: Avoiding fluid overload by choosing the appropriate amount of fluids in patients who are fluid-responsive on one hand, and treating IVF like other medications, on the other hand, are the major changes. Whenever clinicians decide to prescribe IVF, they need to weigh the risks and benefits of giving fluid and also the advantages and side effects of each fluid type in order to optimize patient outcomes.