Development and validation of an age-risk score for mortality predication after thermal injury.

BACKGROUND: In burn patients, the risk of mortality typically decreases as children mature, reaches a nadir at age 21, rises linearly thereafter, and levels off in old age. We hypothesized that a single "age-risk score" (AGESCORE), incorporating a cubic functional form, can be used in predictive models for mortality after burns. METHODS: Data from 6,395 thermally injured patients admitted to a single burn center between January 1, 1950, and December 31, 1999, were used. Variables included age, total burn size, year of discharge, and survival. AGESCORE was defined as follows: -5(age) + 14(age/100) -7(age/10,000). Logistic regression verified the cubic functional form of the age-mortality relationship. Models using a general cubic functional form of age, and AGESCORE, were compared for lack of fit. The stability of AGESCORE was assessed over six distinct treatment eras within the 50-year period. AGESCORE was also validated using data from a different burn center. RESULTS: AGESCORE provided an accurate method for modeling mortality in burn patients across different age groups, burn sizes, eras, and burn centers. CONCLUSION: The benefits of a standardized index of age risk include ease of comparison, reduction of bias, and increased efficiency attributable to statistical parsimony. The applicability of this approach to nonthermal trauma patients remains to be seen.

Standard variables fail to identify patients who will not respond to fluid resuscitation following thermal injury: brief report.

UNLABELLED: Approximately 13% of thermally injured patients fail resuscitation, in that they die during the first 48 h postburn despite full resuscitative efforts. The purpose of this study was to characterize these patients, and to develop a predictor of resuscitation failure. METHODS: Records of 3807 thermally injured patients admitted to this burn centre during 1980-1997 were reviewed. Patients were classified as surviving to hospital discharge ("NONFAIL/LIVE"), as surviving resuscitation but dying later ("NONFAIL/DIE"), or as failing resuscitation ("FAIL"). Ordinal logistic regression was used to develop a predictor of membership in each of these three groups. RESULTS: With respect to total burn size, full-thickness burn size, and inhalation injury, the three groups represented a gradation in injury severity from least severe (NONFAIL/LIVE) to most severe (FAIL). The predictive model had an overall accuracy of 91.6%; however, it correctly classified NONFAIL/LIVE patients more often (97.7% accuracy) than it did NONFAIL/DIE patients (57.5%) or FAIL patients (16.1%). CONCLUSION: Patients who failed resuscitation were more severely injured than those who survived resuscitation, but was not possible accurately to predict who will fail resuscitation using data available on admission.

Evaluation of commercially available fluid-warming devices for use in forward surgical and combat areas.

The fluid-warming capabilities of four individual fluid warmers, i.e., Level 1, FMS 2000, Thermal Angel, and Ranger, were compared to evaluate their potential for medical use in forward military echelons of care. Lactated Ringer's solution (LR) and Hextend at room temperature (20 degrees C) or refrigerated temperature (4-7 degrees C) and packed red blood cells at 4 degrees C to 7 degrees C were used with each warmer at two different flow rates. The FMS 2000 consistently warmed all fluids to approximately 37 degrees C, regardless of the starting temperature or flow rate. The Level 1 and Ranger also efficiently warmed all fluids except cold LR to approximately 37 degrees C. The Thermal Angel generally warmed room temperature fluid, cold Hextend, and packed red blood cells to at least 33 degrees C to 34 degrees C but could not warm cold LR. The clinical standard is to have fluids warmed to 32 degrees C at a minimum and more preferably to 34 degrees C to 35 degrees C. Of the fluid warmers tested, only the Thermal Angel failed to achieve such a temperature in warming cold LR. Data from the present study suggest the Ranger and FMS 2000 to be operationally adaptable to at least echelons 1 and 2, respectively, whereas far-forward use of the Thermal Angel has limitations.