Matthew B. Bloom

Virtual reality applied to procedural testing: the next era.

ObjectiveTo establish the construct validity of a virtual reality-based upper gastrointestinal endoscopy simulator as a tool for the skills training of residents. Summary Background DataPrevious studies have demonstrated the relevance of virtual reality training as an adjunct to traditional operating room learning for residents. The use of specific task trainers, which have the ability to objectively analyze and track user performance, has been shown to demonstrate improvements in performance over time. Using this off-line technology can lessen the financial and ethical concerns of using operative time to teach basic skills. MethodsThirty-five residents and fellows from General Surgery and Gastrointestinal Medicine were recruited for this study. Their performance on virtual reality upper endoscopy tasks was analyzed by computer. Assessments were made on parameters such as time needed to finish the examination, completeness of the examination, and number of wall collisions. Subjective experiences were queried through questionnaires. Users were grouped according to their prior level of experience performing endoscopy. ResultsConstruct validation of this simulator was demonstrated. Performance on visualization and biopsy tasks varied directly with the subjects’ prior experience level. Subjective responses indicated that novice and intermediate users felt the simulation to be a useful experience, and that they would use the equipment in their off time if it were available. ConclusionsVirtual reality simulation may be a useful adjunct to traditional operating room experiences. Construct validity testing demonstrates the efficacy of this device. Similar objective methods of skills evaluation may be useful as part of a residency skills curriculum and as a means of procedural skills testing.

Impact of positive fluid balance on critically ill surgical patients: A prospective observational study

PURPOSE The purpose of this study is to determine the effect of postoperative fluid balance (FB) on subsequent outcomes in acute care surgery (ACS) patients admitted to the surgical intensive care unit (ICU). MATERIAL AND METHODS Acute care surgery patients admitted to the surgical ICU from 06/2012 to 01/2013 were followed up prospectively. Patients were stratified by FB into FB-positive (+) and FB-negative (-) groups by surgical ICU day 5 or day of discharge from the surgical ICU. RESULTS A total of 144 ACS patients met inclusion criteria. Although there was no statistically significant difference in crude mortality (11% for FB [-] vs 15.5% for FB [+]; P=.422], after adjusting for confounding factors, achieving an FB (-) status by day 5 during the surgical ICU stay was associated with an almost 70% survival benefit (adjusted odds ratio [95% confidence interval], 0.31 [0.13, 0.76]; P=.010). In addition, achieving a fluid negative status by day 1 provided a protective effect for both overall and infectious complications (adjusted odds ratio [95% confidence interval], 0.63 [0.45, 0.88]; P=.006 and 0.64 [0.46, 0.90]; P=.010, respectively). CONCLUSIONS In a cohort of critically ill ACS patients, achieving FB (-) status early during surgical ICU admission was associated with a nearly 70% reduction in the risk for mortality.

The impact of implementing a 24/7 open trauma bed protocol in the surgical intensive care unit on throughput and outcomes.

BACKGROUND Increased emergency department (ED) length of stay (LOS) has been associated with increased mortality in trauma patients. In 2010, we implemented a 24/7 open trauma bed protocol in our designated trauma intensive care units (TICUs) to facilitate rapid admission from the ED. This required maintenance of a daily bump list and timely transferring of patients out of the TICU. We hypothesized that ED LOS and mortality would decrease after implementation. METHODS The following data from patients admitted directly from the ED to any ICU were retrospectively compared before (2009) and after (2011) the implementation of a trauma bed protocol at a Level I trauma center: age, sex, Glasgow Coma Scale (GCS) score, shock on admission (systolic blood pressure < 90 mm Hg), mechanism, injury severity scores (Injury Severity Score [ISS] and Abbreviated Injury Scale [AIS] score), ED LOS, ICU readmission rates, and mortality. RESULTS Of the patients, 267 (17%) of 1,611 before and 262 (21%) of 1,266 (p < 0.01) after the protocol were admitted directly to the ICU, despite similar characteristics. ED LOS decreased from 4.2 ± 4.0 hours to 3.1 ± 2.1 hours (p < 0.01) in all patients as well as patients with an ISS of greater than 24 (3.1 ± 2.5 vs. 2.2 ± 1.6, p < 0.05) and a head AIS score of greater than 2 (4.2 ± 4.9 vs. 3.1 ± 2.0, p = 0.01). Mortality was unchanged for all patients (9% vs. 8%, p = 0.58) but trends toward improved mortality were found after protocol implementation inpatients with an ISS of greater than 24 (30% vs. 13%, p = 0.07) and in patients with a head AIS score of greater than 2 (12% vs. 6%, p = 0.08). A greater proportion of total patients were admitted to a designated TICU after implementation (83% vs. 93%, p < 0.01). ICU readmissions were unchanged (0.3% vs. 1.5%, p = 0.21). CONCLUSION The implementation of a 24/7 open trauma bed protocol in the surgery ICU was associated with a decreased ED LOS and increased admissions to designated TICUs in all patients. Improved throughput was achieved without increases in ICU readmissions. LEVEL OF EVIDENCE Therapeutic study, level IV.

Microelectrical mechanical systems in surgery and medicine1

It is apparent that in the year 2001, the methods by which one negotiates the world are becoming more efficient and more powerful. This phenomenon is encountered when checking email or reviewing the latest journal articles on a desktop computer. The trend in microcomputing is evident in surgery, which is certainly at the forefront of miniaturization technology. To take advantage of next generation tools, physicians must first be aware of the current trends in technology, and then understand them well. The need for such an understanding serves as the impetus for this discussion of microelectromechanical systems (MEMSs). MEMS comprise a technology that most use without realizing it. A car with an airbag restraint system, for example, is likely to use a micromechanical system in the form of an accelerometer, which deploys a life-saving airbag (Fig. 1). Other common examples include the nozzle in an inkjet printer, the fuel injection system in a car, and the sensor in a vehicle’s antitheft system. Surgeons, internists, and researchers have always tried to interact directly with the physical domain of the diseases that are fought every day. Surgeons have long used loupes to reapproximate tissues on the microscopic level. Oncology, transplant surgery, and cardiology researchers have tried to approach diseases microscopically. MEMS technology allows us to do this. Most MEMS devices are less than the size of a 50m human hair and can be used singly or in vast groups of millions. Such miniaturization might seem at the outset to be advantageous in all circumstances, but this is not universally true. Some of these devices can be outsized and overpowered by the organic and physiologic processes they encounter, reducing their effectiveness. Because a microscopic dimension is not always efficient, intense planning for the scaling of these devices is imperative. As the medical community continues to rely on computers to enhance treatment, physicians require an instrument that does not only function to compute, but one that also performs actual tasks. MEMS fill this need. MEMS involve integrated circuits, which can actuate, sense, and modify the outside world, on the micrometer scale. One must begin by reviewing the theory of micromechanical devices. These devices are made largely of silicon, the same material used in producing the central processor of a personal computer. They perform on the micron level, having sizes of approximately 10 to hundreds of micrometers. Some are smaller than the width of a human hair. MEMS are generated using a unique fabrication method called micromachining. Each micromachined device will have a particular capability that will interact with the world on the macro scale. Specifically, there are three main advantages to MEMS: size, reliability, and inexpensive production cost. All MEMS fabrication methods share particular common features, which will be discussed in the following sections. There are advantages and disadvantages that are inherent to MEMS technology. To understand these points, it will be useful to have at least a cursory understanding of the MEMS “toolbox.” This article provides insight into the toolbox by dissecting the fabrication process involved in the manufacture of integrated circuits, and will touch on many of the aspects that are involved in the fabrication of micromechanical devices in a manner intended to be useful to the nonengineer physician. The goal is to outfit the reader with a meaningful understanding of the basic science behind each of the real-world applications discussed in Section II of the article. In Section III, there are descriptions of a number of important, existing medical applications of MEMS technology, with a succinct discussion of the advantages and disadvantages of each. Section IV reviews some disadvantages of the technology as an overall field, and No competing interests declared.

Early propranolol after traumatic brain injury is associated with lower mortality.

BACKGROUND &bgr;-Adrenergic receptor blockers (BBs) administered after trauma blunt the cascade of immune and inflammatory changes associated with injury. BBs are associated with improved outcomes after traumatic brain injury (TBI). Propranolol may be an ideal BB because of its nonselective inhibition and ability to cross the blood-brain barrier. We determined if early administration of propranolol after TBI is associated with lower mortality. METHODS All adults (age ≥ 18 years) with moderate-to-severe TBI (head Abbreviated Injury Scale [AIS] score, 3–5) requiring intensive care unit (ICU) admission at a Level I trauma center from January 1, 2013, to May 31, 2015, were prospectively entered into a database. Administration of early propranolol was dosed within 24 hours of admission at 1 mg intravenous every 6 hours. Patients who received early propranolol after TBI (EPAT) were compared with those who did not (non-EPAT). Data including demographics, hospital length of stay (LOS), ICU LOS, and mortality were collected. RESULTS Over 29 months, 440 patients with moderate-to-severe TBI met inclusion criteria. Early propranolol was administered to 25% (109 of 440) of the patients. The EPAT cohort was younger (49.6 years vs. 60.4 years, p < 0.001), had lower Glasgow Coma Scale (GCS) score (11.7 vs. 12.4, p = 0.003), had lower head AIS score (3.6 vs. 3.9, p = 0.001), had higher admission heart rate (95.8 beats/min vs. 88.4 beats/min, p = 0.002), and required more days on the ventilator (5.9 days vs. 2.6 days, p < 0.001). Similarities were noted in sex, Injury Severity Score (ISS), admission systolic blood pressure, hospital LOS, ICU LOS, and mortality rate. Multivariate regression showed that EPAT was independently associated with lower mortality (adjusted odds ratio, 0.25; p = 0.012). CONCLUSION After adjusting for predictors of mortality, early administration of propranolol after TBI was associated with improved survival. Future studies are needed to identify additional benefits and optimal dosing regimens. LEVEL OF EVIDENCE Therapeutic study, level IV.

Body mass index strongly impacts the diagnosis and incidence of heparin-induced thrombocytopenia in the surgical intensive care unit.

BACKGROUND The obese state has been linked to several immune-mediated conditions. Our objective was to examine the association of body mass index (BMI) with the diagnosis of heparin-induced thrombocytopenia (HIT). METHODS Prospectively collected data on patients in the surgical and cardiac intensive care unit suspected of having HIT between January 2007 and August 2014 were analyzed. Patients were categorized into five discrete BMI (kg/m2) groups and compared. Data collected included Warkentin 4-T scores, antiplatelet factor 4 (anti-PF4OD) values, serotonin release assay values, and thromboembolic diseases. HIT positivity was defined as serotonin release assay value greater than 20%. RESULTS Of 304 patients meeting inclusion criteria, mean (SD) age was 62.1 (16.5) years, 59% were male, and mean (SD) BMI was 27 (6) kg/m2. Thirty-six (12%) were positive for HIT. Incidence of HIT increased progressively with BMI (0%, 8%, 11%, 19%, 36%; p < 0.001). Compared with patients with normal BMI, patients with a BMI of 30 kg/m2 to 39.9 kg/m2 had a 200% increase in the odds for HIT (odds ratio [OR], 2.94; 95% confidence interval [CI], 1.20–7.54; p = 0.019), while patients with a BMI of 40 kg/m2 or greater had a 600% increase (OR, 6.98; 95% CI, 1.59–28.2; p = 0.012). After regression analysis, BMI remained an independent predictor of the development of HIT (adjusted OR per kg/m2, 1.08; 95% CI, 1.02–1.14; p = 0.010). Anti-PF4OD values greater than or equal to 2.0 also increased with BMI (p < 0.001). In-hospital mortality increased significantly with BMI above normal (p = 0.026). Warkentin 4-T scores, deep venous thrombosis, pulmonary embolism, and stroke incidence did not correlate with changes in BMI. CONCLUSION Increasing BMI seems to be strongly associated with increased rates of HIT in intensive care unit patients. Obesity is an important new clinical variable for estimating the pretest probability of HIT, and patient “thickness” could be considered a fifth “T” of the 4-T scoring system. Additional biochemical work is indicated to decipher the role of obesity in this immune-mediated condition. LEVEL OF EVIDENCE Prognostic/epidemiologic study, level III.

Impact of body mass index on injury in abdominal stab wounds: implications for management.

BACKGROUND Although it is assumed that obese patients are naturally protected against anterior abdominal stab wounds, the relationship has never been formally studied. We sought to examine the impact of body mass index (BMI) on severity of sustained injury, need for operation, and patient outcomes. MATERIALS AND METHODS We conducted a review of all patients presenting with abdominal stab wounds at an urban level I trauma center from January 2000-December 2012. Patients were divided into groups based on their BMI (<18.5, 18.5-29.9, 30-35, and >35). Data abstracted included baseline demographics, physiologic data, and characterization of whether the stab wound had violated the peritoneum, caused intra-abdominal injury, or required an operation that was therapeutic. The one-sided Cochran-Armitage trend test was used for significance testing of the protective effect. RESULTS Of 281 patients with abdominal stab wounds, 249 had complete data for evaluation. Chest and abdomen abbreviated injury scale trends decreased with increasing BMI, as did overall injury severity score, the percent of patients severely injured (injury severity score ≥ 25), and length of intensive care unit stay. Rates of peritoneal violation (100%, 84%, 77%, and 74%; P = 0.077), visceral injury (83%, 56%, 50%, and 30%; P = 0.022), and injury requiring a therapeutic operation (67%, 45%, 40%, and 20%; P = 0.034) all decreased with increasing BMI. Patients in the thinnest group required an operation three times more often than those in the most obese. CONCLUSIONS Increased BMI protects patients with abdominal stab wounds and is associated with lower incidence of severe injury and need for operation. Heavier patients may be more suitable to observation and serial examinations, whereas very thin patients are more likely to require an operation and be critically injured.

Prospective Trial of House Staff Time to Response and Intervention in a Surgical Intensive Care Unit: Pager vs. Smartphone

OBJECTIVE The objective of the study was to characterize house staff time to response and intervention when notified of a patient care issue by pager vs. smartphone. We hypothesized that smartphones would reduce house staff time to response and intervention. DESIGN Prospective study of all electronic communications was conducted between nurses and house staff between September 2015 and October 2015. The 4-week study period was randomly divided into two 2-week study periods where all electronic communications between intensive care unit nurses and intensive care unit house staff were exclusively by smartphone or by pager, respectively. Time of communication initiation, time of house staff response, and time from response to clinical intervention for each communication were recorded. Outcomes are time from nurse contact to house staff response and intervention. SETTING Single-center surgical intensive care unit of Cedars-Sinai Medical Center in Los Angeles, California, an academic tertiary care and level I trauma center. PARTICIPANTS All electronic communications occurring between nurses and house staff in the study unit during the study period were considered. During the study period, 205 nurse-house staff electronic communications occurred, 100 in the phone group and 105 in the pager group. RESULTS House staff response to communication time was significantly shorter in the phone group (0.5 [interquartile range = 1.7] vs. 2 [3]min, p < 0.001). Time to house staff intervention after response was also significantly more rapid in the phone group (0.8 [1.7] vs. 1 [2]min, p = 0.003). CONCLUSIONS Dedicated clinical smartphones significantly decrease time to house staff response after electronic nursing communications compared with pagers.