Evaluating Adult Patient Temperatures During Lower Spinal Surgery

Not Applicable

Completed

Interventions: Device: Heated Ventilator Circuit
Device: Standard Ventilator Circuit

Brief Summary: The purpose of this study is to evaluate patients' temperatures after using one of two ventilator circuits (breathing systems): the ANAPOD™ Heat and Humidification System (ANAPOD™ system) or the standard ventilator circuit with a heat-moisture exchanger (standard ventilator). The ANAPOD™ system will provide additional heat and humidity to patients through their breathing tube while the standard ventilator will not. The investigators are doing this research study to find out if the ventilator circuit providing additional heat and humidity will keep patients warmer during surgery and after surgery.

Detailed Description: Patients were randomly assigned to either the treatment group or the control group prior to surgery. Prior to induction, patients in the control group were given inspiratory gas at ambient air temperature (20-22 degrees Celsius) and patients in the treatment group were given inspiratory gas at warmed temperatures (40-41 degrees Celsius). All patients were induced with general anesthesia in the supine position and repositioned prone following endotracheal intubation and placement of an esophageal stethoscope with a temperature sensor, as per usual hospital practice. Esophageal temperatures were recorded within 30 minutes of the baseline esophageal temperature and every 10 minutes thereafter for the first hour post-induction. All patients had a blanket and forced air warming applied to their lower extremities and upper back at 43 degrees Celsius after draping. All patients had esophageal temperature measurements recorded every 30 minutes until the patient was repositioned supine. Core temperatures were recorded four hours post-induction for those patients reaching that timeframe.

Recruitment & Eligibility

Inclusion Criteria

Elective spine surgery anticipated greater than three hours in duration
Posterior approach
An operative site between lumbar one and sacral one
Involving two or more levels with fusion and/or instrumentation and/or revisions
American Society of Anesthesiologists (ASA) Status of I-III

Exclusion Criteria

Arm && Interventions

Group	Intervention	Description
Heated Ventilator Circuit	Heated Ventilator Circuit	Heated and humidified inspired gases using the ANAPOD™ Heat and Humidification System (Westmed; Tucson, Arizona, USA) circuit prior to induction of general anesthesia in addition to standard ventilation and temperature management.
Standard Ventilator Circuit	Standard Ventilator Circuit	Standard ventilation and temperature management.

Primary Outcome Measures

Name	Time	Method
Core Body Temperature	Approximately four hours post-induction of general anesthesia (or last recorded temperature)	Core body temperature will be taken in the esophagus. The last recorded esophageal temperature will be used for surgeries not reaching 3 hours duration.

Secondary Outcome Measures

Name	Time	Method
Estimated Blood Loss	duration of surgery	The estimated blood loss per case was determined by the anesthesia provider by measuring the volume of blood in the suction canister while taking into account the amount of irrigation solution used.
Intraoperative Core Temperatures Post-induction	Approximately 30 minutes, 60 minutes, 120 minutes post-induction of general anesthesia	Core body temperature will be taken in the esophagus after general anesthesia induction.
Number of Subjects With Post-operative Shivering	Approximately 2 hours after completion of the surgery	Shivering in the post-anesthesia care unit will be assessed using the Bedside Shivering Assessment Scale. This is a 4 point scale and rate shivering as the following: absent, mild, moderate, or severe. Only the highest degree of patient shivering was used in the analysis.
Hospital Length of Stay	Surgery to hospital discharge	Number of days in the hospital
Overall Post-operative Temperature	PACU arrival	Temperature at Post Anesthesia Care Unit (PACU) arrival.
Number of Participants With Transfusion Within 48 Hours of Surgery	Within 48 hours of surgery	Requirement of blood transfusion within 48 hours of surgery