Patient and Operative Factors Predict Risk of Discretionary Prolonged Postoperative Mechanical Ventilation in a Broad Surgical Cohort.

BACKGROUND: Patients undergoing surgery with general anesthesia and endotracheal intubation are ideally extubated upon case completion, as prolonged postoperative mechanical ventilation (PPMV) has been associated with poor outcomes. However, some patients require PPMV for surgical reasons, such as airway compromise, while others remain intubated at the discretion of the anesthesia provider. Incidence and risk factors for discretionary PPMV (DPPMV) have been described in individual surgical subspecialties and intensive care unit (ICU) populations, but are relatively understudied in a broad surgical cohort. The present study seeks to fill this gap and identify the perioperative risk factors that predict DPPMV. METHODS: After obtaining institutional review board (IRB) exemption, existing electronic health record databases at our large referral center were retrospectively queried for adult surgeries performed between January 2018 and December 2020 with general anesthesia, endotracheal intubation, and by surgical services that do not routinely leave patients intubated for surgical reasons. Patients who arrived to the ICU intubated after surgery were identified as experiencing DPPMV. Selection of candidate risk factors was performed with LASSO-regularized logistic regression, and surviving variables were used to generate a multivariable logistic regression model of DPPMV risk. RESULTS: A total of 32,915 cases met inclusion criteria, of which 415 (1.26%) experienced DPPMV. Compared to extubated patients, those with DPPMV were more likely to have undergone emergency surgery (42.9% versus 3.4%; P < .001), surgery during an existing ICU stay (30.8% versus 2.8%; P < 0.001), and have 20 of the 31 elixhauser comorbidities ( P < .05 for each comparison), among other differences. A risk model with 12 variables, including American Society of Anesthesiologists (ASA) physical classification status, emergency surgery designation, four Elixhauser comorbidities, surgery during an existing ICU stay, surgery duration, estimated number of intraoperative handoffs, and vasopressor, sodium bicarbonate, and albuterol administration, yielded an area under the receiver operating characteristic curve of 0.97 (95% confidence interval, 0.96-0.97) for prediction of DPPMV. CONCLUSIONS: DPPMV was uncommon in this broad surgical cohort but could be accurately predicted using readily available patient-specific and operative factors. These results may be useful for preoperative risk stratification, postoperative resource allocation, and clinical trial planning.

The Management of Pregnant Trauma Patients: A Narrative Review.

Trauma is the leading nonobstetric cause of maternal death and affects 1 in 12 pregnancies in the United States. Adhering to the fundamentals of the advanced trauma life support (ATLS) framework is the most important component of care in this patient population. Understanding the significant physiologic changes of pregnancy, especially with regard to the respiratory, cardiovascular, and hematologic systems, will aid in airway, breathing, and circulation components of resuscitation. In addition to trauma resuscitation, pregnant patients should undergo left uterine displacement, insertion of 2 large bore intravenous lines placed above the level of the diaphragm, careful airway management factoring in physiologic changes of pregnancy, and resuscitation with a balanced ratio of blood products. Early notification of obstetric providers, initiation of secondary assessment for obstetric complications, and fetal assessment should be undertaken as soon as possible but without interference to maternal trauma assessment and management. In general, viable fetuses are monitored by continuous fetal heart rate for at least 4 hours or more if abnormalities are detected. Moreover, fetal distress may be an early sign of maternal deterioration. When indicated, imaging studies should not be limited out of fear for fetal radiation exposure. Resuscitative hysterotomy should be considered in patients approaching 22 to 24 weeks of gestation, who arrive in cardiac arrest or present with profound hemodynamic instability due to hypovolemic shock.

Training Anesthesiology Residents to Care for the Traumatically Injured in the United States.

Training and education for trauma anesthesiology have been predicated on 2 primary pathways: learning through peripheral "complex, massive transfusion cases"-an assumption that is flawed due to the unique demands, skills, and knowledge of trauma anesthesiology-or learning through experiential education, which is also incomplete due to its unpredictable and variable exposure. Residents may receive training from senior physicians who may not maintain a trauma-focused continuing medical education. Further compounding the issue is the lack of fellowship-trained clinicians and standardized curricula. The American Board of Anesthesiology (ABA) provides a section for trauma education in its Initial Certification in Anesthesiology Content Outline. However, many trauma-related topics also fall under other subspecialties, and the outline excludes "nontechnical" skills. This article focuses on the training of anesthesiology residents and proposes a tier-based approach to teaching the ABA outline by including lectures, simulation, problem-based learning discussions, and case-based discussions that are proctored in conducive environments by knowledgeable facilitators.

A Prospective Multicenter Comparison of Trauma and Injury Severity Score, American Society of Anesthesiologists Physical Status, and National Surgical Quality Improvement Program Calculator's Ability to Predict Operative Trauma Outcomes.

BACKGROUND: Trauma outcome prediction models have traditionally relied upon patient injury and physiologic data (eg, Trauma and Injury Severity Score [TRISS]) without accounting for comorbidities. We sought to prospectively evaluate the role of the American Society of Anesthesiologists physical status (ASA-PS) score and the National Surgical Quality Improvement Program Surgical Risk-Calculator (NSQIP-SRC), which are measurements of comorbidities, in the prediction of trauma outcomes, hypothesizing that they will improve the predictive ability for mortality, hospital length of stay (LOS), and complications compared to TRISS alone in trauma patients undergoing surgery within 24 hours. METHODS: A prospective, observational multicenter study (9/2018-2/2020) of trauma patients ≥18 years undergoing operation within 24 hours of admission was performed. Multiple logistic regression was used to create models predicting mortality utilizing the variables within TRISS, ASA-PS, and NSQIP-SRC, respectively. Linear regression was used to create models predicting LOS and negative binomial regression to create models predicting complications. RESULTS: From 4 level I trauma centers, 1213 patients were included. The Brier Score for each model predicting mortality was found to improve accuracy in the following order: 0.0370 for ASA-PS, 0.0355 for NSQIP-SRC, 0.0301 for TRISS, 0.0291 for TRISS+ASA-PS, and 0.0234 for TRISS+NSQIP-SRC. However, when comparing TRISS alone to TRISS+ASA-PS (P = .082) and TRISS+NSQIP-SRC (P = .394), there was no significant improvement in mortality prediction. NSQIP-SRC more accurately predicted both LOS and complications compared to TRISS and ASA-PS. CONCLUSIONS: TRISS predicts mortality better than ASA-PS and NSQIP-SRC in trauma patients undergoing surgery within 24 hours. The TRISS mortality predictive ability is not improved when combined with ASA-PS or NSQIP-SRC. However, NSQIP-SRC was the most accurate predictor of LOS and complications.

Pro-Con Debate: Viscoelastic Hemostatic Assays Should Replace Fixed Ratio Massive Transfusion Protocols in Trauma.

Major trauma patients at risk of traumatic coagulopathy are commonly treated with early clotting factor replacement to maintain hemostasis and prevent microvascular bleeding. In the United States, trauma transfusions are often dosed by empiric, low-ratio massive transfusion protocols, which pair plasma and platelets in some ratio relative to the red cells, such as the "1:1:1" combination of 1 units of red cells, 1 unit of plasma, and 1 donor's worth of pooled platelets. Empiric transfusion increases the rate of overtransfusion when unnecessary blood products are administered based on a formula and not on at patient's hemostatic profile. Viscoelastic hemostatic assays (VHAs) are point-of-care hemostatic assays that provided detailed information about abnormal clotting pathways. VHAs are used at many centers to better target hemostatic therapies in trauma. This Pro/Con section will address whether VHA guidance should replace empiric fixed ratio protocols in major trauma.

Pro-Con Debate: Prehospital Blood Transfusion-Should It Be Adopted for Civilian Trauma?

Exsanguination is the leading cause of death in severely injured patients; nevertheless, prehospital blood transfusion (PHT) remains a controversial topic. Here, we review the pros and cons of PHT, which is now routine in treatment of military trauma patients in the civilian setting. While PHT may improve survival in those who suffer blunt injury or require prolonged transport from the site of injury, PHT for civilian trauma generally is not supported by high-quality evidence. This article was originally presented as a pro-con debate at the 2020 meeting of the European Society of Anesthesiology and Intensive Care.

Surgical rib fixation in traumatic rib fractures: is it warranted?

PURPOSE OF REVIEW: Traumatic chest wall injuries and rib fractures remain a prevalent injury. Despite many advances, these injuries result in high morbidity and mortality. Surgical stabilization of rib fractures (SSRF) is increasing in utilization with expanding indications. Recent studies have demonstrated that many patients may benefit from surgical intervention. RECENT FINDINGS: Over the past 20 years the indications and timing of SSRF has evolved. Once reserved mainly for the most extreme of injuries, expanding indications demonstrate that even minimally injured patients may benefit from intervention regarding pain control, respiratory complications, and overall mortality. SUMMARY: SSRF has become more prevalent with improving outcomes for patients. Understanding the indications will help expand utilization and improve patient outcomes.

Intraoperative Focused Cardiac Ultrasound for Assessment of Hypotension: A Systematic Review.

Focused cardiac ultrasound (FoCUS) has become a valuable tool to assess unexplained hypotension in critically ill patients. Due to increasing availability of transthoracic echocardiography (TTE) equipment in the operating room, there is a widespread interest in its usefulness for intraoperative diagnosis of hypotension as an alternative to transesophageal echocardiography (TEE). The objective of this systematic review is to evaluate the utility of intraoperative FoCUS to assess patients experiencing unexplained hypotension while undergoing noncardiac surgery. We performed a systematic literature search of multiple publication databases for studies that evaluated the utility of intraoperative FoCUS for assessment and management of unexplained hypotension in patients undergoing noncardiac surgery, including retro- and prospective clinical studies. A summary of the study findings, study quality, and assessment of level of evidence is presented. We identified 2227 unique articles from the literature search, of which 27 were potentially relevant, and 9 were included in this review. The number of patients pooled from these studies was 255, of whom 228 had intraoperative diagnoses with the aid of intraoperative FoCUS. The level of evidence of all studies included was very low according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidelines. This systematic review has demonstrated that FoCUS may be a useful, noninvasive method to differentiate causes of intraoperative hypotension and guide correcting interventions, although the quality of evidence is very low. Further prospective high-quality studies are needed to investigate whether intraoperative FoCUS has a diagnostic utility that is associated with improved outcomes.

Effects of State Law Limiting Postoperative Opioid Prescription in Patients After Cesarean Delivery.

BACKGROUND: The impact of the Florida State law House Bill 21 (HB 21) restricting the duration of opioid prescriptions for acute pain in patients after cesarean delivery is unknown. Our objective was to assess the association of the passage of Florida State law HB 21 with trends in discharge opioid prescription practices following cesarean delivery, necessity for additional opioid prescriptions, and emergency department visits at a large tertiary care center. METHODS: This was a retrospective cohort study conducted at a large, public hospital. The 2 cohorts represented the period before and after implementation of the law. Using a confounder-adjusted segmented regression analysis of an interrupted time series, we evaluated the association between HB 21 and trends in the proportions of patients receiving opioids on discharge, duration of opioid prescriptions, total opioid dose prescribed, and daily opioid dose prescribed. We also compared the need for additional opioid prescriptions within 30 days of discharge and the prevalence of emergency department visits within 7 days after discharge. RESULTS: Eight months after implementation of HB 21, the mean duration of opioid prescriptions decreased by 2.9 days (95% confidence interval [CI], 5.2-0.5) and the mean total opioid dose decreased by 20.1 morphine milligram equivalents (MME; 95% CI, 4-36.3). However, there was no change in the proportion of patients receiving discharge opioids (95% CI of difference, -0.1 to 0.16) or in the mean daily opioid dose (mean difference, 5.3 MME; 95% CI, -13 to 2.4). After implementation of the law, there were no changes in the proportion of patients who required additional opioid prescriptions (2.1% vs 2.3%; 95% CI of difference, -1.2 to 1.5) or in the prevalence of emergency department visits (2.4% vs 2.2%; 95% CI of difference, -1.6 to 1.1). CONCLUSIONS: Implementation of Florida Law HB 21 was associated with a lower total prescribed opioid dose and a shorter duration of therapy at the time of hospital discharge following cesarean delivery. These reductions were not associated with the need for additional opioid prescriptions or emergency department visits.

Parallel veno-venous and veno-arterial extracorporeal membrane circuits for coexisting refractory hypoxemia and cardiovascular failure: a case report.

BACKGROUND: The complexity of extracorporeal membrane oxygenation (ECMO) techniques continues to evolve. Different cannulation methods and configurations have been proposed as a response to a challenging cardiovascular and pulmonary physiology of the patients. The use of parallel ECMO circuits represents a unique and novel approach for patients with refractory respiratory failure and cardiovascular collapse with very large body surface areas. CASE PRESENTATION: We present the case of a 25-year-old morbidly obese male patient admitted for severe acute respiratory distress syndrome (ARDS) and refractory hypoxemia, requiring institution of double cannulation for veno-venous ECMO. Since his hypoxemia persisted, likely due to insufficient flows given his large body surface area, an additional drainage venous cannula was implemented to provide higher flows, temporarily addressing his oxygenation status. Unfortunately, the patient developed concomitant cardiogenic shock refractory to inotropic support and extracorporeal fluid removal, further worsening his oxygenation status, thus the decision was to institute four-cannulation/parallel-circuits veno-venous and veno-arterial ECMO, successfully controlling both refractory hypoxemia and cardiogenic shock. CONCLUSIONS: Our case illustrates a novel and complex approach for combined severe ARDS and cardiovascular collapse through the use of parallel veno-venous and veno-arterial ECMO circuits, and exemplifies the expansion of ECMO techniques and its life-saving capabilities when conservative approaches are futile.

Management of Respiratory Distress Syndrome due to COVID-19 infection.

The management of Acute Respiratory Distress Syndrome (ARDS) secondary to the novel Coronavirus Disease 2019 (COVID-19) proves to be challenging and controversial. Multiple studies have suggested the likelihood of an atypical pathophysiology to explain the spectrum of pulmonary and systemic manifestations caused by the virus. The principal paradox of COVID-19 pneumonia is the presence of severe hypoxemia with preserved pulmonary mechanics. Data derived from the experience of multiple centers around the world have demonstrated that initial clinical efforts should be focused into avoid intubation and mechanical ventilation in hypoxemic COVID-19 patients. On the other hand, COVID-19 patients progressing or presenting into frank ARDS with typical decreased pulmonary compliance, represents another clinical enigma to many clinicians, since routine therapeutic interventions for ARDS are still a subject of debate.

Recommendation of New Medical Alarms Based on Audibility, Identifiability, and Detectability in a Randomized, Simulation-Based Study.

OBJECTIVES: Accurate and timely identification of existing audible medical alarms is not adequate in clinical settings. New alarms that are easily heard, quickly identifiable, and discernable from one another are indicated. The "auditory icons" (brief sounds that serve as metaphors for the events they represent) have been proposed as a replacement to the current international standard. The objective was to identify the best performing icons based on audibility and performance in a simulated clinical environment. DESIGN: Three sets of icon alarms were designed using empirical methods. Subjects participated in a series of clinical simulation experiments that examined the audibility, identification accuracy, and response time of each of these icon alarms. A statistical model that combined the outcomes was used to rank the alarms in overall efficacy. We constructed the "best" and "worst" performing sets based on this ranking and prospectively validated these sets in a subsequent experiment with a new subject sample. SETTING: Experiments were conducted in simulated ICU settings at the University of Miami. SUBJECTS: Medical trainees were recruited from a convenience sample of nursing students and anesthesia residents at the institution. INTERVENTIONS: In Experiment 1 (formative testing), subjects were exposed to one of the three sets of alarms; identical setting and instruments were used throughout. In Experiment 2 (summative testing), subjects were exposed to one of the two sets of alarms, assembled from the best and worst performing alarms from Experiment 1. MEASUREMENTS AND MAIN RESULTS: For each alarm, we determined the minimum sound level to reach audibility threshold in the presence of background clinical noise, identification accuracy (percentage), and response time (seconds). We enrolled 123 medical trainees and professionals for participation (78 with < 6 yr of training). We identified the best performing icon alarms for each category, which matched or exceeded the other candidate alarms in identification accuracy and response time. CONCLUSIONS: We propose a set of eight auditory icon alarms that were selected through formative testing and validated through summative testing for adoption by relevant regulatory bodies and medical device manufacturers.

Can variable practice habits and injection port dead-volume put patients at risk?

Injection ports used to administer medications and draw blood samples have inherent dead-volume. This volume can potentially lead to inadvertent drug administration, contribute to erroneous laboratory values by dilution of blood samples, and increase the risk of vascular air embolism. We sought to characterize provider practice in management of intravenous (IV) and arterial lines and measure dead-volumes of various injection ports. A survey was circulated to anesthesiology physicians and nurses to determine practice habits when administering medications and drawing blood samples. Dead-volume of one and four-way injection ports was determined by injecting methylene blue to simulate medication administration or blood sample aspiration and using absorption spectroscopy to measure sample concentration. Among the 65 survey respondents, most (64.52%) increase mainstream flow rate to flush medication given by a 1-way injection port. When using 4-way stopcocks, 56.45% flush through the same injection site. To obtain a sample from an arterial line, 67.74% draw back blood and collect the sample from the same 4-way stopcock; 32.26% use a different stopcock. Mean (SD) dead-volume in microliters ranged from 0.1 (0.0) to 5.6 (1.0) in 1-way injection ports and from 54.1 (2.8) to 126.5 (8.3) in 4-way injection ports. The practices of our providers when giving medications and drawing blood samples are variable. The dead-volume associated with injection ports used at our institution may be clinically significant, increasing errors in medication delivery and laboratory analysis.

Auditory Icon Alarms Are More Accurately and Quickly Identified than Current Standard Melodic Alarms in a Simulated Clinical Setting.

BACKGROUND: Current standard audible medical alarms are difficult to learn and distinguish from one another. Auditory icons represent a new type of alarm that has been shown to be easier to learn and identify in laboratory settings by lay subjects. In this study, we test the hypothesis that icon alarms are easier to learn and identify than standard alarms by anesthesia providers in a simulated clinical setting. METHODS: Twenty anesthesia providers were assigned to standard or icon groups. Experiments were conducted in a simulated intensive care unit. After a brief group-specific alarm orientation, subjects identified patient-associated alarm sounds during the simulation and logged responses via a tablet computer. Each subject participated in the simulation twice and was exposed to 32 alarm annunciations. Primary outcome measures were response accuracy and response times. Secondary outcomes included assessments of perceived fatigue and task load. RESULTS: Overall accuracy rate in the standard alarm group was 43% (mean) and in the icon group was 88% (mean). Subjects in the icon group were 26.1 (odds ratio [98.75% CI, 8.4 to 81.5; P < 0.001]) times more likely to correctly identify an alarm. Response times in the icon group were shorter than in the standard alarm group (12 vs. 15 s, difference 3 s [98.75% CI ,1 to 5; P < 0.001]). CONCLUSIONS: Under our simulated conditions, anesthesia providers more correctly and quickly identified icon alarms than standard alarms. Subjects were more likely to perceive higher fatigue and task load when using current standard alarms than icon alarms.

Incidence and Operative Factors Associated With Discretional Postoperative Mechanical Ventilation After General Surgery.

BACKGROUND: Mechanical ventilation after general surgery is associated with worse outcomes, prolonged hospital stay, and increased health care cost. Postoperatively, patients admitted to the intensive care unit (ICU) may be categorized into 1 of 3 groups: extubated patients (EXT), patients with objective medical indications to remain ventilated (MED), and patients not meeting these criteria, called "discretional postoperative mechanical ventilation" (DPMV). The objectives of this study were to determine the incidence of DPMV in general surgery patients and identify the associated operative factors. METHODS: At a large, tertiary medical center, we reviewed all surgical cases performed under general anesthesia from April 1, 2008 to February 28, 2015 and admitted to the ICU postoperatively. Patients were categorized into 1 of 3 cohorts: EXT, MED, or DPMV. Operative factors related to the American Society of Anesthesiologists Physical Status (ASA PS), duration of surgery, surgery end time, difficult airway management, intraoperative blood and fluid administration, vasopressor infusions, intraoperative arterial blood gasses, and ventilation data were collected. Additionally, anesthesia records were reviewed for notes indicating a reason or rationale for postoperative ventilation. Categorical variables were compared by χ test, and continuous variables by analysis of variance or Kruskal-Wallis H test. Categorical variables are presented as n (%), and continuous variables as mean ± standard deviation or median (interquartile range) as appropriate. Significance level was set at P≤ .05. RESULTS: Sixteen percent of the 3555 patients were categorized as DPMV and 12.2% as MED. Compared to EXT patients, those classified as DPMV had received significantly less fluid (2757 ± 2728 mL vs 3868 ± 1885 mL; P < .001), lost less blood during surgery (150 [20-625] mL vs 300 [150-600] mL; P< .001), underwent a shorter surgery (199 ± 215 minutes vs 276 ± 143 minutes; P< .001), but received more blood products, 900 (600-1800) mL vs 600 (300-900) mL. The DPMV group had more patients with high ASA PS (ASA III-V) than the EXT group: 508 (90.4%) vs 1934 (75.6%); P< .001. Emergency surgery (ASA E modifier) was more common in the DPMV group than the EXT group: 145 (25.8%) vs 306 (12%), P< .001, respectively. Surgery end after regular working hours was not significantly higher with DPMV status compared to EXT. DPMV cohort had fewer cases with difficult airway when compared to EXT or MED. When compared to MED patients, those classified as DPMV received less fluid (2757 ± 2728 mL vs 4499 ± 2830 mL; P< .001), lost less blood (150 [20-625] mL vs 500 [200-1350] mL; P < .001), but did not differ in blood products transfused or duration of surgery. CONCLUSIONS: In our tertiary medical center, patients often admitted to the ICU on mechanical ventilation without an objective medical indication. When compared to patients admitted to the ICU extubated, those mechanically ventilated but without an objective indication had a higher ASA PS class and were more likely to have an ASA E modifier. A surgery end time after regular working hours or difficult airway management was not associated with higher incidence of DPMV.

Factors Affecting Acoustics and Speech Intelligibility in the Operating Room: Size Matters.

INTRODUCTION: Noise in health care settings has increased since 1960 and represents a significant source of dissatisfaction among staff and patients and risk to patient safety. Operating rooms (ORs) in which effective communication is crucial are particularly noisy. Speech intelligibility is impacted by noise, room architecture, and acoustics. For example, sound reverberation time (RT60) increases with room size, which can negatively impact intelligibility, while room objects are hypothesized to have the opposite effect. We explored these relationships by investigating room construction and acoustics of the surgical suites at our institution. METHODS: We studied our ORs during times of nonuse. Room dimensions were measured to calculate room volumes (VR). Room content was assessed by estimating size and assigning items into 5 volume categories to arrive at an adjusted room content volume (VC) metric. Psychoacoustic analyses were performed by playing sweep tones from a speaker and recording the impulse responses (ie, resulting sound fields) from 3 locations in each room. The recordings were used to calculate 6 psychoacoustic indices of intelligibility. Multiple linear regression was performed using VR and VC as predictor variables and each intelligibility index as an outcome variable. RESULTS: A total of 40 ORs were studied. The surgical suites were characterized by a large degree of construction and surface finish heterogeneity and varied in size from 71.2 to 196.4 m (average VR = 131.1 [34.2] m). An insignificant correlation was observed between VR and VC (Pearson correlation = 0.223, P = .166). Multiple linear regression model fits and ß coefficients for VR were highly significant for each of the intelligibility indices and were best for RT60 (R = 0.666, F(2, 37) = 39.9, P < .0001). For Dmax (maximum distance where there is <15% loss of consonant articulation), both VR and VC ß coefficients were significant. For RT60 and Dmax, after controlling for VC, partial correlations were 0.825 (P < .0001) and 0.718 (P < .0001), respectively, while after controlling for VR, partial correlations were -0.322 (P = .169) and 0.381 (P < .05), respectively. CONCLUSIONS: Our results suggest that the size and contents of an OR can predict a range of psychoacoustic indices of speech intelligibility. Specifically, increasing OR size correlated with worse speech intelligibility, while increasing amounts of OR contents correlated with improved speech intelligibility. This study provides valuable descriptive data and a predictive method for identifying existing ORs that may benefit from acoustic modifiers (eg, sound absorption panels). Additionally, it suggests that room dimensions and projected clinical use should be considered during the design phase of OR suites to optimize acoustic performance.

Low End-Tidal Carbon Dioxide at the Onset of Emergent Trauma Surgery Is Associated With Nonsurvival: A Case Series.

BACKGROUND: End-tidal carbon dioxide (EtCO2) is a valuable marker of the return of adequate circulation after cardiac arrest due to medical causes. Previously, the prognostic value of capnography in trauma has been studied among limited populations in prehospital and emergency department settings. We aimed to investigate the relationship between early intraoperative EtCO2 and nonsurvival of patients undergoing emergency surgery at a level 1 academic trauma center as a case series. If there is a threshold below which survival was extremely unlikely, it might be useful in guiding decision-making in the early termination of futile resuscitative efforts. METHODS: After institutional review board approval, a data set was created to investigate the relationship between EtCO2 values at the onset of emergent trauma surgery and nonsurvival. Patients who were admitted and transferred to the operating room (OR) directly from a resuscitation bay were identified using the Ryder Center trauma registry (October 1, 2013, to June 30, 2016). Electronic records from the hospital's anesthesia information management system were queried to identify the matching anesthesia records. The maximum EtCO2 values within 5 and 10 minutes of the onset of mechanical ventilation in the OR were determined for patients undergoing general anesthesia with mechanical ventilation. Patients were divided into 2 groups: those who were discharged from the hospital alive (survivors) and those who died in the hospital before discharge (nonsurvivors). The threshold EtCO2 giving a positive predictive value of 100% for in-hospital mortality was determined from a graphical analysis of the data. Association of determined threshold and mortality was analyzed using the 2-tailed Fisher exact test. RESULTS: There were 1135 patients who met the inclusion criteria. Within the first 5 minutes of the onset of mechanical ventilation in the OR, if the maximum EtCO2 value was ≤20 mm Hg, hospital mortality was 100% (21/21, 95% binomial confidence interval, 83.2%-100%). CONCLUSIONS: A maximum EtCO2 ≤20 mm Hg within 5 minutes of the onset of mechanical ventilation in the OR may be useful in decision-making related to the termination of resuscitative efforts during emergent trauma surgery. However, a large-scale study is needed to establish the statistical reliability of this finding before potential adoption.