Beth A. Ballinger

Quantification of hypercoagulable state after blunt trauma: Microparticle and thrombin generation are increased relative to injury severity, while standard markers are not

BACKGROUND Major trauma is an independent risk factor for developing venous thromboembolism. While increases in thrombin generation and/or procoagulant microparticles have been detected in other patient groups at greater risk for venous thromboembolism, such as cancer or coronary artery disease, this association has yet to be documented in trauma patients. This pilot study was designed to characterize and quantify thrombin generation and plasma microparticles in individuals early after traumatic injury. METHODS Blood was collected in the trauma bay from 52 blunt injured patients (cases) and 19 uninjured outpatients (controls) and processed to platelet poor plasma to allow for (1) isolation of microparticles for identification and quantification by flow cytometry, and (2) in vitro thrombin generation as measured by calibrated automatic thrombography. Data collected are expressed as either mean ± standard deviation or median with interquartile range. RESULTS Among the cases, which included 39 men and 13 women (age, 40 ± 17 years), the injury severity score was 13 ± 11, the international normalized ratio was 1.0 ± 0.1, the thromboplastin time was 25 ± 3 seconds, and platelet count was 238 ± 62 (thousands). The numbers of total (cell type not specified) procoagulant microparticles, as measured by Annexin V staining, were increased compared to nontrauma controls (541 ± 139/μL and 155 ± 148/μL, respectively; P < .001). There was no significant difference in the amount of thrombin generated in trauma patients compared to controls; however, peak thrombin was correlated to injury severity (Spearman correlation coefficient R, 0.35; P = .02). CONCLUSION Patients with blunt trauma have greater numbers of circulating procoagulant microparticles and increased in vitro thrombin generation. Future studies to characterize the cell-specific profiles of microparticles and changes in thrombin generation kinetics after traumatic injury will determine whether microparticles contribute to the hypercoagulable state observed after injury.

Practical Management of Postoperative Atrial Fibrillation after Noncardiac Surgery

Postoperative atrial fibrillation (POAF) is a common adverse event after surgical procedures. This complication has been extensively studied in the cardiothoracic surgery literature because of its high incidence (up to 60%); however, the specific incidence, pathophysiology, risk factors, and optimal management strategies are less well known in the noncardiothoracic surgery population. According to current reports, mainly observational studies, POAF occurs in 5% to 10% of patients undergoing noncardiothoracic surgery. This estimate is likely conservative and widely variable, as most published reports base their rates on a mixed noncardiothoracic surgical population containing many surgical specialties. Unlike in cardiothoracic surgery, telemetry might not always be used during the initial postoperative period, which can also add to an underestimation of true incidence. When analyzed by type of noncardiothoracic surgery, abdominal, trauma, and vascular specialties often have higher incidence rates compared with other surgical groups. In an observational study of 370,447 patients undergoing major noncardiac surgery, patients undergoing abdominal surgery had an 82% higher risk for POAF than patients undergoing other noncardiac operations (adjusted odds ratio 1⁄4 1.82; 95% CI, 1.72 1.93). Likewise, Christians and colleagues showed in their cohort of patients with POAF undergoing noncardiothoracic operations, 39% had abdominal surgery, 22% vascular surgery, and the remaining 39% consisted of orthopaedic, neurologic, plastic surgery, and ophthalmologic surgical patients. Postoperative atrial fibrillation can lead to increased length of stay and subsequently elevated health care costs; therefore, its prevention and appropriate management are important areas to research. Several studies also cite an increased risk of mortality with POAF. Mortality remains an established association with POAF, however, causality is uncertain, as patients in whom atrial fibrillation develops generally have underlying comorbidities and greater associated cardiac risk. Similar to POAF after cardiac procedures, peak onset of POAF occurs between 0 and 4 days following noncardiac surgery. It is also not normally recurrent if the underlying cause is corrected or reversed.

A “Fundamentals” Train-the-Trainer Approach to Building Pediatric Critical Care Expertise in the Developing World

Pediatric Fundamental Critical Care Support (PFCCS) is an educational tool for training non-intensivists, nurses, and critical care practitioners in diverse health-care settings to deal with the acute deterioration of pediatric patients. Our objective was to evaluate the PFCCS course as a tool for developing a uniform, reproducible, and sustainable model for educating local health-care workers in the optimal management of critically ill children in the Republic of Georgia. Over a period of 18 months and four visits to the country, we worked with Georgian pediatric critical care leadership to complete the following tasks: (1) survey health-care needs within the Republic of Georgia, (2) present representative PFCCS lectures and simulation scenarios to evaluate interest and obtain “buy-in” from key stakeholders throughout the Georgian educational infrastructure, and (3) identify PFCCS instructor candidates. Georgian PFCCS instructor training included the following steps: (1) US PFCCS consultant and content experts presented PFCCS course to Georgian instructor candidates. (2) Simulation learning principles were taught and basic equipment was acquired. (3) Instructor candidates presented PFCCS to Georgian learners, mentored by PFCCS course consultants. Objective evaluation and debriefing with instructor candidates concluded each visit. Between training visits Georgian instructors translated PFCCS slides to the Georgian language. Six candidates were identified and completed PFCCS instructor training. These Georgian instructors independently presented the PFCCS course to 15 Georgian medical students. Student test scores improved significantly from pretest results (n = 14) (pretest: 38.7 ± 7 vs. posttest 62.7 ± 6, p < 0.05). A Likert-type scale of 1 to 5 (1 = not useful or effective, 5 = extremely useful or effective) was used to evaluate each student’s perception regarding (1) relevance of course content to clinical work students rated as median (IQR): (a) relevance of PFCCS content to clinical work, 5 (4–5); (b) effectiveness of lecture delivery, 4 (3–4); and (c) value of skill stations for clinical practice, 5 (4–5). Additionally, the mean (±SD) responses were 4.6 (±0.5), 3.7 (±0.6), and 4.5 (±0.6), respectively. Training local PFCCS instructors within an international environment is an effective method for establishing a uniform, reproducible, and sustainable approach to educating health-care providers in the fundamentals of pediatric critical care. Future collaborations will evaluate the clinical impact of PFCCS throughout the Georgian health-care system.

1070: REFRACTORY HYPOXEMIA

Critical Care Medicine • Volume 46 • Number 1 (Supplement) www.ccmjournal.org Learning Objectives: A 51 yo male with morbid obesity (BMI 52) and OSA presented with syncope and abdominal pain. Evaluation showed left adrenal hemorrhage. He was intubated for airway protection and taken for therapeutic angioembolization. Ventilator settings were VC 500 ml; PEEP 15; FiO2 0.6. After angiography, he was admitted to ICU. He was placed on a Hamilton G5 ventilator with SIMV rate 24; Vt 480 ml; PEEP 15. ABGs were PaO2 60/ PaCO2 45. The P/F ratio was 100. Peak Inspiratory (PIP) and Plateau Pressures (Pplat) were 32 and 30. Chest XR showed bilateral atelectasis and perihilar congestion compared to previously. Methods: Esophageal balloon manometry was used as a surrogate for transpulmonary pressure during mechanical ventilation and management of refractory hypoxemia. Results: Due to refractory hypoxemia and habitus, therapy changes were made: Vt was reduced to 390 ml (6ml/kg/PBW) and an esophageal manometry balloon was placed to assess respiratory mechanics and optimize PEEP. After proper balloon catheter placement was confirmed with the presence of cardiac oscillations, the expiratory transpulmonary pressure (Ptrans E) was -11. PEEP was increased until measured Ptrans E was 0. PEEP increased from 15 to 29, while maintaining Ptrans E of 0. After PEEP optimization, PIP briefly increased to 44 before dropping to 35–36; Pplat transiently rose to 44 then returned to 30, indicating lung recruitment and alveoli stabilization. No change in hemodynamics occurred. To accomplish balloon placement and accurately measure Ptrans data required he receive sedation and neuromuscular blockade. Within 30 minutes of PEEP optimization at 29, with a Ptrans E =0, the FiO2 was titrated from 0.6 to 0.3, with no SpO2 change. ABG 2 hours later showed PaO2 83. The P/F ratio improved to276. Respiratory mechanics, or driving pressures (Ptrans Insp – Ptrans Exp), were monitored; values were consistently below 15, despite PIPs in the 30s low 40’s. We saw an acceptable Pplat and maintained low driving pressures despite aggressive upward PEEP titration. This augmented PEEP strategy was associated with higher PIP, but did not compromise pulmonary mechanics. Esophageal balloon manometry is a surrogate for Ptrans measurement. Identifying “true” lung distending pressure with Ptrans aids management of refractory hypoxemia by optimizing PEEP; it can preserve a lung protective strategy by serial monitoring of driving pressures in those with low chest wall compliance.

889: JUST MOVE IT! IMPLEMENTING EARLY EXERCISE AND PROGRESSIVE MOBILITY IN A SURGICAL/TRAUMA ICU/PCU

Copyright