Intraoperative Temperature Monitoring with Zero Heat Flux Technology (3M SpotOn Sensor) in Comparison with Tympanic and Oesophageal Temperature and Hypotermia Risk Factors: An Observational Study

Abstract

Objective Inadvertent hypothermia (body temperature below 35°C) is a common and avoidable challenge during surgery under anaesthesia. It is related to coagulation (clotting) disorders, an increase in blood loss, and a higher rate of wound infection. One of the methods for non-invasive monitoring of the core body temperature is the 3M SpotOn zero heat flux method. In this approach, sensors placed at the frontal region of the patient measure the skin temperature by creating an isothermic channel. The study aimed to determine the risk factors for hypothermia and compare the 3M SpotOn zero heat flux method with the tympanic membrane (eardrum) and oesophageal (food pipe) temperature measurement methods. Design Observational. Data sources The patients’ data were collected, including age, gender, weight, BMI, other illnesses, smoking history, type of anaesthesia, duration of surgery, operating room temperature, pulse rate, blood pressure, blood loss, and transfusions. Body temperature was measured by the tympanic membrane method before and after surgery, oesophageal method during surgery, and SpotOn measurements throughout all three periods were recorded. Eligibility criteria Inclusion criteria was: adult patients, both genders, who had undergone major abdominal cancer surgery at the trialists’ institution, in whom the SpotOn zero heat flux, tympanic membrane, and oesophageal temperature measurement methods had all been used. Participant exclusion criteria was the absence of recorded data. Results In this study, inadvertent intraoperative hypothermia incidence was 38.1% in the recovery room. Although gender, presence of comorbidities, history of smoking, administration of epidural anaesthesia, and requirement of blood transfusion [red blood cells (RBCs) and fresh frozen plasma (FFP)] did not affect hypothermia significantly during admission to the recovery room, prewarming the patient throughout the operation prevented the occurrence of hypothermia significantly (p=0.004). Additionally, as the American Society of Anaesthesiologists (ASA) physical status score worsened, the rate of hypothermia increased significantly (Frequency: 1 st degree, 29.4%; 2 nd degree, 47.5%; 3 rd degree, 66.7%; X 2 Slope- p=0.047). Conclusion The most significant risk factor was found to be not prewarming the patient as a strict procedure, and as the ASA physical status score worsened, the rate of hypothermia increased significantly. Besides, the SpotOn method provided temperature measurements as good as the oesophageal temperature measurements. Clinical Trial registration: ISRCTN 14027708.

Accuracy of a zero-heat-flux thermometer in cardiac surgery, a prospective, multicentre, method comparison study

“…The major strength is, that we were able to get temperature recordings from 100 patients who experience a fast and relatively large drop in core temperature down to core temperatures of 33.6 °C. In addition, the majority of our patients were ASA physical status classification III or IV which is known to increase the hypothermia rate significantly 20 and enabled us to observe low core temperatures.…”

Accuracy of a Zero-Heat-Flux Thermometer in cardiac surgery: a prospective, multicentre, observational study

“…The major strength is, that we were able to get temperature recordings from 100 patients who experience a fast and relatively large drop in core temperature down to core temperatures of 33.6°C. In addition, the majority of our patients were ASA physical status classi cation III or IV which is known to increase the hypothermia rate signi cantly (Erdost et al, 2021) and enabled us to observe low core temperatures.…”

Soft Wearable Thermal Devices Integrated with Machine Learning

“…During perioperative settings, the ZHF devices were clinically proven to measure CBT as accurately as the invasive esophageal and nasopharyngeal techniques. [ 14 ] In perioperative settings, the mean CBT bias was found to be 0.03 °C with population limits of agreement between −0.93 °C and 0.98 °C. [ 6 ] However, the ZHF device requires a connection to an electrical outlet and is not suitable to use in resource‐limited settings.…”