60 - Investigation of Unplanned Intraoperative Hypothermia Patterns and Relationships in Surgical Patients Warmed with Forced Air: A Secondary Analysis
Purpose: The purpose of this study was to determine the effect of preoperative forced-air warming on intraoperative temperature trajectories for adult patients undergoing non-cardiac surgical procedures with general anesthesia. Literature Review: Unplanned intraoperative hypothermia (UIH) is associated with numerous postoperative complications including blood loss, postoperative infection, prolonged postanesthetic recovery, cardiac morbidity, delayed hospital discharge, and mortality. Despite standard use of intraoperative forced air warming, UIH remains a routine event for up to 64% of surgical patients. Notably, patterns of UIH and temperature trajectories in patients warmed with forced air are poorly described in the research literature.Research Questions: 1. What is the relationship between hypothermia time and perioperative timing of forced air warming of patients undergoing non-cardiac surgery?2. Is the trajectory of heat loss based on surgical procedure, anesthesia type, or timing of forced air warming in patients undergoing non-cardiac surgery?
Methods: Electronic medical record data from adult patients (>= 18 years old) who underwent a non-cardiac inpatient or outpatient surgery between January 2014 and December 2018 were abstracted. Data Analysis: Descriptive statistics including measures of central tendency and frequencies were calculated for the entire sample at the surgical case level, stratified by prewarming. Mixed effects linear regression was conducted to predict temperature trending from the following variables: time from anesthesia start; BMI; gender; prewarming; the two-way interaction between time from anesthesia start and prewarming; and the three-way interaction among time from anesthesia start, gender, and BMI. Continuous variables were modeled with restricted cubic splines to express non-linear relationships and random intercept by each surgical case were modeled to allow for individual differences in base temperature.
Results: Data abstraction yielded 603,039 intraoperative temperatures from 29,114 surgical cases. 526 of these surgical cases were prewarmed. Modeling suggests that patients warmed preoperatively will have a higher temperature at the time of initial anesthesia administration compared to patients who do not receive prewarming. Results also indicate that prewarmed patients will maintain a higher temperature than patients who were not prewarmed.
Conclusions: Results support prewarming to increase intraoperative temperatures throughout a surgical procedure. Findings suggest that prewarming reduces intraoperative hypothermic time and subsequently, the incidence of adverse events associated with UIH. Perioperative Implications: This study provides evidence that may lead to further research in the tailoring of active warming interventions based on patient presentation. Additionally, this study addressed the AORN research priorities of contributing to perioperative nursing science and improvement of patient care.