title: End-tidal CO2on admission is associated with hemorrhagic shock and predicts the need for massive transfusion as defined by the critical administration threshold: A pilot study.
abstract: BACKGROUND
  Critical administration threshold (≥3 units of packed red blood cells/h or CAT+) has been proposed as a new definition for massive transfusion (MT) that includes volume and rate of blood transfusion. CAT+ has been shown to eliminate survivor bias and be a better predictor of mortality than the traditional MT (>10 units/24h). End-tidal CO2(ET CO2) negatively correlates with lactate and is an early predictor of shock in trauma patients. We conducted a pilot study to test the hypothesis that low ET CO2on admission predicts CAT+.
  
  
  METHODS
  ET CO2via capnography and serum lactate were prospectively collected on admission for 131 patients requiring trauma team activation. Demographic data were obtained from patient charts. Excluded were patients with isolated head injuries, traumatic arrests, or pre-hospital intubations. CAT± status was determined for each hour up to 6h from admission as described; likewise, MT± status was determined up to 24h from admission.
  
  
  RESULTS
  After exclusion criteria, 67 patients were analyzed. Mean age was 41.2 (SD 18.5). Thirty-three patients had a blunt mechanism of injury (49%), median ISS was 9 (interquartile range 4-19), and there were 6 deaths (9%). ET CO2and lactate were negatively correlated by Spearman rank-based correlation (rho=-0.41, p=0.0006). Twenty-one (31%) and 8 (12%) patients were CAT+ and traditional MT+, respectively. There were a significantly greater proportion of patients with ISS>15, ET CO2<35, or who died found to be CAT+. A binomial logistic regression model adjusting for age, SBP <90, HR, and ISS >15 revealed ET CO2< 35 to be independently predictive of CAT+ (OR 9.24, 95% CI 1.51-56.57, p=0.016).
  
  
  CONCLUSIONS
  This pilot study demonstrated that low ET CO2had strong association with standard indicators for shock and was predictive of patients meeting CAT+ criteria in the first 6h after admission. Further study to verify these results and to elucidate CAT criteria's association with mortality will require a larger sample size.
authors.affiliation: Department of Surgery, Jacobi Medical Center Bronx, NY, United States; Albert Einstein College of Medicine, Bronx, NY, United States. Electronic address: melvinomd@gmail.com.
authors.forename: Melvin E
authors.initials: ME
authors.lastname: Stone
authors.affiliation: Albert Einstein College of Medicine, Bronx, NY, United States. Electronic address: skalata91@gmail.com.
authors.forename: Stanley
authors.initials: S
authors.lastname: Kalata
authors.affiliation: Department of Surgery, Jacobi Medical Center Bronx, NY, United States. Electronic address: aliveris@montefiore.org.
authors.forename: Anna
authors.initials: A
authors.lastname: Liveris
authors.affiliation: Department of Surgery, Jacobi Medical Center Bronx, NY, United States. Electronic address: adornoza@vcu.edu.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Adorno
authors.affiliation: Department of Surgery, Jacobi Medical Center Bronx, NY, United States. Electronic address: shy16@case.edu.
authors.forename: Shira
authors.initials: S
authors.lastname: Yellin
authors.affiliation: Department of Surgery, Jacobi Medical Center Bronx, NY, United States; Albert Einstein College of Medicine, Bronx, NY, United States. Electronic address: Edward.Chao@NBHN.net.
authors.forename: Edward
authors.initials: E
authors.lastname: Chao
authors.affiliation: Department of Surgery, Jacobi Medical Center Bronx, NY, United States; Albert Einstein College of Medicine, Bronx, NY, United States. Electronic address: Srinivas.Reddy@NBHN.net.
authors.forename: Srinivas H
authors.initials: SH
authors.lastname: Reddy
authors.affiliation: Department of Surgery, Jacobi Medical Center Bronx, NY, United States; Albert Einstein College of Medicine, Bronx, NY, United States. Electronic address: Michael.Jones@NBHN.net.
authors.forename: Michael
authors.initials: M
authors.lastname: Jones
authors.affiliation: Department of Surgery, Jacobi Medical Center Bronx, NY, United States. Electronic address: Carlos.Vargas@NBHN.net.
authors.forename: Carlos
authors.initials: C
authors.lastname: Vargas
authors.affiliation: Department of Surgery, Jacobi Medical Center Bronx, NY, United States; Albert Einstein College of Medicine, Bronx, NY, United States. Electronic address: Sheldon.Teperman@NBHN.net.
authors.forename: Sheldon
authors.initials: S
authors.lastname: Teperman
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001803:Blood Transfusion / Q000379:methods*; D019296:Capnography / Q000379:methods; D002245:Carbon Dioxide / Q000097:blood*; D002985:Clinical Protocols; D005260:Female; D006470:Hemorrhage / Q000150:complications / Q000401:mortality*; D017052:Hospital Mortality; D006801:Humans; D016857:Hypocapnia / Q000209:etiology / Q000401:mortality*; D015601:Injury Severity Score; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012771:Shock, Hemorrhagic / Q000209:etiology / Q000401:mortality* / Q000517:prevention & control; D013997:Time Factors; D014193:Trauma Centers; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D014947:Wounds and Injuries / Q000150:complications / Q000401:mortality / Q000628:therapy*
chemical_list: D015415:Biomarkers; D002245:Carbon Dioxide
keywords: Capnography; End tidal CO(2); Hemorrhagic shock; Massive transfusion