Troy G. Seelhammer

Kinetic estimated glomerular filtration rate and acute kidney injury in cardiac surgery patients.

PURPOSE To determine how a formula to estimate kinetically changing glomerular filtration rate (keGFR) relates to serum creatinine changes and to compare the discriminatory ability of keGFR to that of perioperative change in serum creatinine to predict acute kidney injury (AKI) and mortality. MATERIALS AND METHODS Retrospective cohort study at a single-tertiary-care Midwestern university hospital of 4022 patients admitted to the intensive care unit between January 2006 and January 2012 immediately after cardiac surgery. MEASUREMENTS AND MAIN RESULTS Of 4022 patients, 1031 (25.6%) developed at least AKI stage 1 and 1106 (27.5%) developed AKI-min. Patients who developed AKI stage 1 or AKI-min had a greater decrease in keGFR, both by absolute amounts and by percentage. After adjusting for other factors with logistic regression, keGFR had good discrimination (c statistic = 0.787 and 0.749, respectively) in predicting AKI and operative mortality. CONCLUSION Despite no change in immediate perioperative serum creatinine levels, keGFR fell and this predicted subsequent AKI. Using keGFR enables identification of patients who, despite unchanged postoperative creatinine, incur clinically significant kidney injury based on reduction in GFR and increased mortality.

Early prediction of extracorporeal membrane oxygenation eligibility for severe acute respiratory distress syndrome in adults.

PURPOSE Appropriately identifying and triaging patients with newly diagnosed acute respiratory distress syndrome (ARDS) who may progress to severe ARDS is a common clinical challenge without any existing tools for assistance. MATERIALS AND METHODS Using a retrospective cohort, a simple prediction score was developed to improve early identification of ARDS patients who were likely to progress to severe ARDS within 7 days. A broad array of comorbidities and physiologic variables were collected for the 12-hour period starting from intubation for ARDS. Extracorporeal membrane oxygenation (ECMO) eligibility was determined based on published criteria from recent ECMO guidelines and clinical trials. Separate data-driven and expert opinion approaches to prediction score creation were completed. RESULTS The study included 767 patients with moderate or severe ARDS who were admitted to the intensive care unit between January 1, 2005, and December 31, 2010. In the data-driven approach, incorporating the ARDS index (a novel variable incorporating oxygenation index and estimated dead space), aspiration, and change of Pao2/fraction of inspired oxygen ratio into a simple prediction model yielded a c-statistic (area under the receiver operating characteristic curve) of 0.71 in the validation cohort. The expert opinion-based prediction score (including oxygenation index, change of Pao2/fraction of inspired oxygen ratio, obesity, aspiration, and immunocompromised state) yielded a c-statistic of 0.61 in the validation cohort. CONCLUSIONS The data-driven early prediction ECMO eligibility for severe ARDS score uses commonly measured variables of ARDS patients within 12 hours of intubation and could be used to identify those patients who may merit early transfer to an ECMO-capable medical center.

Management of Neurogenic Pulmonary Edema and Differential Hypoxemia in an Adult Supported on Venoarterial Extracorporeal Membrane Oxygenation

PATIENTS SUPPORTED on peripheral venoarterial extracorporeal membrane oxygenation (VA-ECMO) can have differential hypoxemia if cardiac function is regained in the clinical setting of poor gas exchange within the native pulmonary bed. Differential hypoxemia is demonstrated by hypoxemia of the upper extremities, brain, and myocardium while adequate oxygen perfusion is maintained in the lower extremities through extracorporeal membrane oxygenation (ECMO). Management of differential hypoxemia in this patient was complicated by acute onset of neurogenic pulmonary edema (NPE), an uncommon complication of anoxic brain injury that compromised oxygenation through the native pulmonary bed. To the authors’ knowledge, this is the first case report of rescue VA-ECMO for cardiac arrest resulting in differential hypoxemia in the setting of NPE.

O uso de flumazenil para depressão respiratória associada ao benzodiazepínico na recuperação pós‐anestésica: riscos e resultados

BACKGROUND AND OBJECTIVES The primary aim was to determine risk factors for flumazenil administration during postanesthesia recovery. A secondary aim was to describe outcomes among patients who received flumazenil. METHODS Patients admitted to the postanesthesia recovery room at a large, academic, tertiary care facility after surgery under general anesthesia from January 1, 2010, to April 30, 2015, were identified and matched to 2 controls each, by age, sex, and surgical procedure. Flumazenil was administered in the recovery phase immediately after general anesthesia, according to the clinical judgment of the anesthesiologist. Demographic, procedural, and outcome data were extracted from the electronic health record. Conditional logistic regression, accounting for the 1:2 matched-set case-control study designs, was used to assess characteristics associated with flumazenil use. RESULTS The incidence of flumazenil administration in the postanesthesia care unit was 9.9 per 10,000 (95% CI, 8.4-11.6) general anesthetics. History of obstructive sleep apnea (Odds Ratio [OR]=2.27; 95% CI 1.02-5.09), longer anesthesia (OR=1.13; 95% CI 1.03-1.24 per 30minutes), use of total intravenous anesthesia (OR=6.09; 95% CI 2.60-14.25), and use of benzodiazepines (OR=8.17; 95% CI 3.71-17.99) were associated with risk for flumazenil administration. Among patients who received midazolam, cases treated with flumazenil received a higher median (interquartile range) dose than controls: 3.5mg (2.0-4.0mg) vs. 2.0mg (2.0-2.0mg), respectively (p<0.001). Flumazenil use was correlated with a higher rate of unanticipated noninvasive positive pressure ventilation, longer postanesthesia care unit stay, and increased rate of intensive care unit admissions. CONCLUSIONS Patients who required flumazenil postoperatively had received a higher dosage of benzodiazepines and utilized more postoperative health care resources. More conservative perioperative use of benzodiazepines may improve postoperative recovery and use of health care resources.

Practical Implementation of Failure Mode and Effects Analysis for Extracorporeal Membrane Oxygenation Activation

Extracorporeal membrane oxygenation (ECMO) is used to treat severe hypoxemic respiratory failure and as a rescue therapy for patients with cardiopulmonary arrest within a narrow window of time. A failure modes and effects analysis (FMEA) was conducted to analyze the clinical and operational processes leading to delays in initiating ECMO. FMEA determined these highest-risk failure modes that were contributing to process failure: (1) ECMO candidacy not determined in time, (2) no or incomplete evaluation for ECMO prior to consult or arrest, (3) ECMO team not immediately available, and (4) cannulation not completed in time. When implemented collectively, a total of 4 interventions addressed more than 95% of the system failures. These interventions were (1) ECMO response pager held by a team required for decision, (2) distribution of institutionally defined inclusion/exclusion criteria, (3) educational training for clinicians consulting the ECMO team, and (4) establishment of a mobile ECMO insertion cart.

Maintenance of Drug-eluting Stent Patency through Use of a Cangrelor Infusion in the Clinical Setting of Massive Pulmonary Hemorrhage and Venoarterial Extracorporeal Membrane Oxygenation

We report ultra-short–acting parenteral P2Y12 inhibitor, cangrelor, for maintenance of fresh drug-eluting stent patency concurrent pulmonary hemorrhage and cardiogenic shock requiring central venoarterial extracorporeal membrane oxygenation. In the setting of stent placement after acute coronary syndrome, standard of care includes indefinite aspirin use plus 12 months of P2Y12 inhibitor to avoid in-stent thrombosis. Cangrelor therapy, with its downregulation of platelet activation and aggregation, was initiated at one-half the recommended percutaneous coronary intervention dosing (2 mcg/kg/min) and maintained patency during central venoarterial extracorporeal membrane oxygenation.