Perioperative hypothermia is a common complication during total knee arthroplasty (TKA) and may increase the risk of shivering, delayed anesthetic recovery, and postoperative complications. This historical control study aims to evaluate the effectiveness and safety of intraoperative forced-air warming in preventing perioperative hypothermia in patients undergoing primary unilateral TKA. A total of 240 patients were included. Patients in the historical control group received routine passive warming measures, while patients in the intervention group received additional forced-air warming during the perioperative period. Core body temperature, incidence of inadvertent perioperative hypothermia, anesthetic recovery outcomes, postoperative complications, and safety outcomes were evaluated.
This single-center historical control study was conducted at Shanghai 6th People's Hospital between May 2018 and December 2018 to evaluate the effectiveness of intraoperative forced-air warming for preventing perioperative hypothermia in patients undergoing total knee arthroplasty (TKA). A total of 240 patients undergoing primary unilateral TKA were enrolled and divided into two groups according to the study period. Patients enrolled between May 2018 and August 2018 were assigned to the historical control group and received routine passive warming measures, including warmed intravenous fluids, warmed irrigation fluids, operating room temperature control, and cotton blanket coverage. Patients enrolled between September 2018 and December 2018 were assigned to the intervention group and received additional active warming using a forced-air warming system during the perioperative period. The forced-air warming system was initiated 30 minutes before anesthesia induction and continued until transfer to the post-anesthesia care unit (PACU). Core temperature was continuously monitored using a temperature-sensing urinary catheter. The primary outcomes included perioperative core temperature changes and the incidence of inadvertent perioperative hypothermia, defined as core temperature below 36°C at any perioperative time point. Secondary outcomes included postoperative shivering, emergence agitation, anesthetic recovery time, blood loss, postoperative complications, and safety outcomes including skin burns and surgical site infection. This study was approved by the Ethics Committee of Shanghai 6th People's Hospital (Approval No. 05.12.19035). Written informed consent was obtained from all participants before enrollment.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
240
Active perioperative warming using a forced-air warming system initiated 30 minutes before anesthesia induction and continued until transfer to the post-anesthesia care unit.
Routine perioperative warming measures including warmed intravenous fluids, warmed irrigation fluids, operating room temperature control, and cotton blanket coverage.
Shanghai 6th People's Hospital
Shanghai, Shanghai Municipality, China
Incidence of Inadvertent Perioperative Hypothermia
The proportion of participants with core body temperature below 36.0°C at any perioperative time point.
Time frame: From anesthesia induction to 90 minutes after anesthesia completion
Perioperative Core Temperature Change
Core body temperature measured using a temperature-sensing urinary catheter at predefined perioperative time points.
Time frame: From operating room entry to 90 minutes after anesthesia completion
Postoperative Shivering
Incidence and severity of postoperative shivering assessed using a 0-4 shivering scale.
Time frame: From the end of surgery to 24 hours postoperatively
Emergence Agitation
Incidence and severity of emergence agitation assessed using the Richmond Agitation-Sedation Scale (RASS, -5 to +4), where higher positive scores indicate greater agitation.
Time frame: From 30 minutes after surgery to 2 hours postoperatively
Anesthetic Recovery Time
Recovery outcomes including awakening time, extubation time, and PACU length of stay.
Time frame: From the end of anesthesia to 2 hours postoperatively
Intraoperative Blood Loss
Estimated blood loss recorded during the surgical procedure.
Time frame: During surgery
Postoperative Complications
Incidence of postoperative complications including delirium, nausea and vomiting, cardiac adverse events, skin burns, and surgical site infection.
Time frame: From the end of surgery to 30 days postoperatively
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