Incidence and Risk Factors for Postoperative Hypothermia After Orthopaedic Surgery

John P. Kleimeyer, MD; Alex H. S. Harris, PhD; Joseph Sanford, MD; William J. Maloney, MD; Bassam Kadry, MD; Julius A. Bishop, MD

Disclosures

J Am Acad Orthop Surg. 2018;26(24):e497-e503. 

In This Article

Abstract and Introduction

Abstract

Introduction: Postoperative hypothermia is a common complication of orthopaedic surgery associated with increased morbidity. We identified the incidence and risk factors for postoperative hypothermia across orthopaedic surgical procedures.

Methods: A total of 3,822 procedures were reviewed. Hypothermia was defined as temperature <36.0°C. Incidences were calculated and associated risk factors were evaluated by mixed-effects regression analyses.

Results: Hypothermia was observed in 72.5% of patients intraoperatively and 8.3% postoperatively. Risk factors for postoperative hypothermia included intraoperative hypothermia (odds ratio [OR], 2.72), lower preoperative temperature (OR, 1.46), female sex (OR, 1.42), lower body mass index (OR, 1.06 per kg/m2), older age (OR, 1.02 per year), adult reconstruction by specialty (OR, 4.06), and hip and pelvis procedures by anatomic region (OR, 8.76).

Discussion: Intraoperative and postoperative hypothermia are common in patients who have undergone orthopaedic surgery. The high-risk groups identified in this study warrant increased attention and should be targets for interventions to prevent hypothermia and limit morbidity.

Level of Evidence: Level IV, prognostic study

Introduction

Perioperative hypothermia has been identified as an important source of morbidity in orthopaedic surgery.[1,2] Intraoperative hypothermia occurs when thermal autoregulation is abolished under anesthesia[2,3] and increased body surface area (BSA) is exposed to the cool operating room environment.[4,5] Postoperative hypothermia is known to alter systemic and local physiology and can result in increased cardiac events,[6,7] myocardial damage,[8] adrenergic response,[6] altered platelet activity and coagulation,[6] greater perioperative blood loss,[9] postoperative infection,[10–16] and prolonged hospitalization.[12] Evaluation of hypothermia in patients with hip fracture at admission has also demonstrated a 2.1- to 2.8-fold increase in the odds of 30-day mortality at temperatures <36.5°C.[17,18] This group also demonstrated an association with increased serum lactate in hypothermic patients with hip fracture, further implicating an altered physiology in the orthopaedic population.[19]

Optimal management of postoperative hypothermia is prevention. Maintenance of core body temperatures >36.0°C has become a standard of perioperative care.[20] Surgeons and anesthesiologists alike must be aware of the relevant risk factors to effectively modify practice. Although previous studies have evaluated risk factors for postoperative hypothermia in a small subset of orthopaedic procedures,[21–25] a comprehensive and generalizable assessment of risk across all orthopaedic patients and procedures has not been undertaken.

Therefore, the purpose of this study was to determine the incidence of postoperative hypothermia across the range of orthopaedic surgical procedures and subspecialties and to identify patient-, subspecialty-, and anatomic region-related risk factors.

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