Inadvertent perioperative hypothermia prevention strategies for urology surgical patients who received a blood transfusion: A retrospective analysis

OBJECTIVES

This study aimed to establish whether hypothermia was present in patients who required a blood transfusion and underwent a urology procedure, as well as identify staff knowledge and understanding.

PATIENTS AND METHODS

A staff survey was conducted with respondents from a range of clinical settings, with some staff working across more than one area. A retrospective review of 46 medical records was conducted between January 2021 and July 2022. All data were exported into an Excel spreadsheet and analysed.

RESULTS

Staff (70%) were unaware of guidelines informing thermoregulation practices; however, 90% understood the importance of normothermia in the perioperative environment. Medical record review demonstrated temperature monitoring and intervention implementation varied across the perioperative journey, with 20% of patients hypothermic on admission and 89% of the cohort having two or more risk factors.

CONCLUSION

There is no formal process for the management of inadvertent perioperative hypothermia throughout the patient journey at the hospital. A variety of intrinsic factors (age, patient comorbidities, American Society of Anaesthesiologists score) and external factors (patient waiting times, anaesthetic modality, type of procedure, environmental influences), impact each patient's risk of inadvertent perioperative hypothermia.

Measurement and Thermodynamic Modeling of Energy Flux During Intercostal Nerve Cryoablation

INTRODUCTION

Intercostal nerve cryoablation is an increasingly adopted technique to decrease postoperative pain in patients undergoing surgical correction of pectus excavatum (SCOPE). Concerns regarding cryo-induced systemic hypothermia have been raised in pediatric patients; however, assessment of a cooled cryoprobe on body temperature has not been performed. We aimed to determine the energy flux from a maximally cooled cryoprobe and model the possible effects on a whole-body system.

METHODS

To directly measure energy flux, a maximally cooled cryoSPHERE probe (AtriCure, Inc, Mason, OH) was isolated in a well-mixed water bath at 37°C. Real-time temperatures were recorded. Three models were created to estimate intraoperative flux. Perioperative temperatures of 50 patients who received cryoablation during SCOPE were compared to 50 patients who did not receive cryoablation.

RESULTS

Direct calorimetry measured average energy flux of the maximally cooled cryoprobe to be 28 J/s. Thermodynamic modeling demonstrated the following: 1) The highest possible cryoprobe flux is less than estimated basal metabolic rate (BMR) of the average teenager undergoing SCOPE and 2) Flux in a best model of human tissue energy transfer using available literature is far less than the effects of BMR and insensible losses. Clinically, there were no significant differences in the minimum intraoperative, end procedure or first postoperative body temperatures for patients who received cryoablation and those who did not.

CONCLUSIONS

Cryoprobe flux is significantly fewer joules per second than BMR. Furthermore, in a clinical series there were no empiric differences in body temperature due to cryoablation employment, contradicting concerns regarding hypothermia secondary to cryoablation.

Incidence and associated factors of perioperative hypothermia in adult patients at a university-based, tertiary care hospital in Thailand

BACKGROUND

Inadvertent perioperative hypothermia is an unintentional drop in core body temperature to less than 36 °C perioperatively and is associated with many negative outcomes such as infection, a prolonged stay in a recovery room, and decreased patient comfort.

OBJECTIVE

To determine the incidence of postoperative hypothermia and to identify the associated factors with postoperative hypothermia in patients undergoing head, neck, breast, general, urology, and vascular surgery. The incidences of pre- and intraoperative hypothermia were examined as the intermediate outcomes.

MATERIALS AND METHODS

A retrospective chart review was conducted in adult patients undergoing surgery at a university hospital in a developing country for two months (October to November 2019). Temperatures below 36 °C were defined as hypothermia. Univariate and multivariate analyses were used to identify factors associated with postoperative hypothermia.

RESULTS

A total of 742 patients were analyzed, the incidence of postoperative hypothermia was 11.9% (95% CI 9.7%-14.3%), and preoperative hypothermia was 0.4% (95% CI 0.08%-1.2%). Of the 117 patients with intraoperative core temperature monitoring, the incidence of intraoperative hypothermia was 73.5% (95% CI 58.8-90.8%), and hypothermia occurred most commonly after anesthesia induction. Associated factors of postoperative hypothermia were ASA physical status III-IV (OR = 1.78, 95%CI 1.08-2.93, p = 0.023) and preoperative hypothermia (OR = 17.99, 95%CI = 1.57-206.89, p = 0.020). Patients with postoperative hypothermia had a significantly longer stay in the PACU (100 min vs. 90 min, p = 0.047) and a lower temperature when discharged from PACU (36.2 °C vs. 36.5 °C, p < 0.001) than those without hypothermia.

CONCLUSION

This study confirms that perioperative hypothermia remains a common problem, especially in the intraoperative and postoperative periods. High ASA physical status and preoperative hypothermia were associated factors of postoperative hypothermia. In order to minimize the incidence of perioperative hypothermia and enhance patient outcomes, appropriate temperature management should be emphasized in patients at high risk.

REGISTRATION

Clinical Trials.gov (NCT04307095) (13/03/2020).

Comparison of two different uses of underbody forced-air warming blankets for the prevention of hypothermia in patients undergoing arthroscopic shoulder surgery: a prospective randomized study

Background

Forced-air warming (FAW) is an effective method of preventing inadvertent perioperative hypothermia (IPH). However, its warming effects can be influenced by the style and position of the FAW blanket. This study aimed to compare the effects of underbody FAW blankets being placed under or over patients in preventing IPH.

Methods

Patients (n=100) undergoing elective arthroscopic shoulder surgery in the lateral decubitus position were randomized into either under body (UB) group or the over body (OB) group (50 per group). The body temperature of the patients was recorded from baseline to the end of anesthesia. The incidences of postoperative hypothermia and shivering were also collected.

Results

A steady decline in the body temperature was observed in both groups up to 60 minutes after the start of FAW. After 60 minutes of warming, the OB group showed a gradual increase in the body temperature. However, the body temperature still decreased in UB group until 75 minutes, with a low of 35.7℃ ± 0.4℃. Then the body temperature increased mildly and reached 35.8℃ ± 0.4℃ at 90 minutes. After 45 minutes of warming, the body temperature between the groups was significantly different (P < 0.05). The incidence of postoperative hypothermia in the UB group was significantly higher than that in the OB group (P = 0.023).

Conclusions

The body temperature was significantly better with the use of underbody FAW blankets placed over patients than with them placed under patients. However, there was not a clinically significant difference in body temperature. The incidence of postoperative hypothermia was much lower in the OB group. Therefore, placing underbody FAW blankets over patients is recommended for the prevention of IPH in patients undergoing arthroscopic shoulder surgery.

Trial registration

This single-center, prospective, RCT has completed the registration of the Chinese Clinical Trial Center at 13/1/2021 with the registration number ChiCTR2100042071. It was conducted from 14/1/2021 to 30/10/2021 as a single, blinded trial in Sichuan Provincial Orthopedic Hospital.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01597-6.

Prevention and management of perioperative hypothermia in adult elective surgical patients: A systematic review

BACKGROUND

Body temperature is tightly regulated with hormonal and cellular metabolism for normal functioning; however perioperative hypothermia is common secondary to anesthesia and surgical exposure.Prevention and maintaining body temperature should be started 1-2hrs before induction of anesthesia, to do this both active and passive warming system are effective to prevent complications associated with perioperative hypothermia.

METHODS

The aim of this systematic review is to develop a clear clinical practice protocol in prevention and management of perioperative hypothermia for elective adult surgical patients.The study is conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline 2020. After formulating clear criteria for the evidences to be included an appropriate method of searching was conducted by using the Pub Med, Google scholar and Cochrane library using the following MeSH terms: (inadvertent hypothermia AND anesthesia, hypothermia AND perioperative management and thermoregulation AND anesthesia) were used to draw evidences.After a reasonable amount of evidences were collected, appraisal and evaluation of study quality was based on WHO 2011 level of evidence and degree of recommendation. Final conclusions and recommendations are done by balancing the benefits and downsides of alternative management strategies for perioperative management of hypothermia.This systematic review registered with research registry unique identifying number (UIN) of "reviewregistry1253" in addition the overall AMSTAR 2 quality of this systematic review is moderate level.

DISCUSSION

Preserving a patient's body temperature during anesthesia and surgery is to minimize heat loss by reducing radiation and convection from the skin, evaporation from exposed surgical areas, and cooling caused by the introduction of cold intravenous fluids.

CONCLUSION

Hypothermia is least monitored complication during anesthesia and surgery results cardiac abnormalities, impaired wound healing, increased surgical site infections, shivering and delayed postoperative recovery, and coagulopathies.

Resistant fabric warming is a viable alternative to forced-air warming to prevent inadvertent perioperative hypothermia during hemiarthroplasty in the elderly

BACKGROUND

Surgical site infection (SSI) is associated with inadvertent perioperative hypothermia (IPH). This can be prevented by active patient warming. However, results from comparisons of warming techniques are conflicting. They are based mostly on elective surgery, are from small numbers of patients, and are dominated by the market leader, forced-air warming (FAW). Furthermore, the definition of hypothermia is debatable and systematic reviews of warming systems conclude that a stricter control of temperature is required to study the benefits of warming.

AIM

To analyse core temperatures in detail in a large subset of elderly patients who took part in a randomized trial of patient warming following hemiarthroplasty who had received constant zero-flux thermometry to record their temperature.

METHODS

Regression models with a fixed effect for warming group and covariates related to temperature were compared for 257 participants randomized to FAW or resistant fabric warming (RFW) from a prior clinical trial.

FINDINGS

Those in the RFW group were -0.08°C cooler and had a cumulative hypothermia score -1.87 lower than those in the FAW group. There was no difference in the proportion of hypothermic patients at either <36.5°C or <36.0°C.

CONCLUSIONS

This is the first study to provide accurate temperature measurements in patients undergoing a procedure predominantly under regional rather than general anaesthetic. It shows that RFW is a viable alternative to FAW for preventing IPH during hemiarthroplasty. Further studies are needed to measure the benefits of patient warming in terms of clinically important outcomes.

Reducing Implant Infection in Orthopaedics (RIIiO): Results of a pilot study comparing the influence of forced air and resistive fabric warming technologies on postoperative infections following orthopaedic implant surgery

BACKGROUND

Active warming during surgery prevents perioperative hypothermia but the effectiveness and postoperative infection rates may differ between warming technologies.

AIM

To establish the recruitment and data management strategies needed for a full trial comparing postoperative infection rates associated with forced air warming (FAW) versus resistive fabric warming (RFW) in patients aged >65 years undergoing hemiarthroplasty following fractured neck of femur.

METHODS

Participants were randomized 1:1 in permuted blocks to FAW or RFW. Hypothermia was defined as a temperature of <36°C at the end of surgery. Primary outcomes were the number of participants recruited and the number with definitive deep surgical site infections.

FINDINGS

A total of 515 participants were randomized at six sites over a period of 18 months. Follow-up was completed for 70.1%. Thirty-seven participants were hypothermic (7.5% in the FAW group; 9.7% in the RFW group). The mean temperatures before anaesthesia and at the end of surgery were similar. For the primary clinical outcome, there were four deep surgical site infections in the FAW group and three in the RFW group. All participants who developed a postoperative infection had antibiotic prophylaxis, a cemented prosthesis, and were operated under laminar airflow; none was hypothermic. There were no serious adverse events related to warming.

CONCLUSION

Surgical site infections were identified in both groups. Progression from the pilot to the full trial is possible but will need to take account of the high attrition rate.

The health economic benefits of perioperative patient warming for prevention of blood loss and transfusion requirements as a consequence of inadvertent perioperative hypothermia

Active warming of patients is recommended by The National Institute for Health and Care Excellence (NICE) to prevent inadvertent perioperative hypothermia (IPH). This paper examines the cost effectiveness of one consequence of IPH, an increase in blood loss and the resulting transfusion risk. We quantified the risk and modelled two patient pathways, one with and one without warming, across two different surgery types. We were able to demonstrate the cost effectiveness of active warming based on one consequence even allowing for uncertainties in the model.

A nurse-led audit on the incidence and management of inadvertent hypothermia in an operating theatre department of an Irish hospital

Inadvertent perioperative hypothermia (IPH) is a common problem associated with perioperative patients which can have significant consequences for them during surgery and in the immediate postoperative period. Recognising and managing IPH remains an important aspect of perioperative nursing and is a significant factor in maintaining patient safety, achieving positive surgical outcomes and patient satisfaction. A nurse-led clinical audit was undertaken in the operating theatre department of a major teaching hospital in Ireland to establish the incidence and management of IPH in the department. One hundred (n = 100) patients were included in the audit, both children and adults. Results of the audit were used to inform quality improvement initiatives, with the purpose of improving patient care standards in the operating theatre department in that hospital.