Effect of pre-warmed intravenous fluids on perioperative hypothermia and shivering after ambulatory surgery under monitored anesthesia care

Inadvertent Perioperative Hypothermia in Ambulatory Surgery Patients: Incidence, Risk Factors, and Prevention Initiatives

PURPOSE

Although the number and complexity of ambulatory surgical interventions has grown considerably over the years, it has not been fully established whether hypothermia still poses a risk for these interventions. In this study, we aimed to determine the incidence, risk factors, and methods applied to prevent perioperative hypothermia in ambulatory surgery patients.

DESIGN

A descriptive research design was used.

METHODS

The study was conducted with 175 patients between May 2021 and March 2022 in the outpatient units of a training and research hospital in Mersin, Turkey. Data were collected using the Patient Information and Follow-up Form.

FINDINGS

The incidence of perioperative hypothermia was 20% in ambulatory surgery patients. Hypothermia developed in 13.7% of the patients at the 0th minute at the PACU, and 96.6% of the patients were not warmed intraoperatively. We noted a statistically significant relationship between perioperative hypothermia and advanced age (≥60 years), high American Society of Anesthesiologists' (ASA) class, and low hematocrit values. In addition, we determined that the female gender, presence of chronic diseases, general anesthesia, and a long operation time were other risk factors for hypothermia in the perioperative period.

CONCLUSIONS

The incidence of hypothermia during ambulatory surgeries is lower than that in inpatient surgeries. The warming rate of ambulatory surgery patients, which is quite low, can be improved by increasing the awareness of the perioperative team and following the guidelines.

Verification of an intravenous fluid warmer: A prospective, two-center observational trial

Objectives

Avoiding inadvertent hypothermia during surgery is important. Intravenous fluid warmers used intraoperatively are critical for maintaining euthermia. We sought to prospectively evaluate the performance of the parylene-coated enFlow™ intravenous fluid warmer in patients undergoing surgery.

Methods

This was a prospective two-center observational clinical trial performed in inpatient surgical services of two large academic hospital systems. After written informed consent, patients were enrolled in the trial. All patients were adults scheduled for a surgery that was expected to last for at least 1 h with the administration of at least 1 L of fluid warmed prior to infusion. Patient temperature was recorded in the preoperative unit, at the induction of anesthesia, and then every 15 or 30 min until the end of surgery. Temperature monitoring continued in the recovery unit. The parylene-coated enFlow™ intravenous fluid warmer was used in addition to the usual patient warming techniques. The primary outcome was the average core temperature, and secondary analyses assessed individual temperature measurements, temperature measurements during specific time periods, and rate of hypothermic events.

Results

In all, 50 patients (29 males) with a mean age of 64 years were included in the analysis. The mean surgical time was 195 min and patients received an average of 1142 mL of fluids. Core temperature dropped by only 0.3°C approximately 60 min after induction and recovered back to the baseline level approximately 60 min later. There was no correlation between flow rate and measured core body temperature.

Conclusions

The parylene-coated enFlow intravenous fluid warmer was able to warm fluids at all flow rates during prolonged surgery. The results showed that enFlow performed as expected.

Perioperative active warming strategies in children: a protocol for a multicentre, prospective, randomized controlled trial

Introduction

Inadvertent perioperative hypothermia (IPH) refers to a core body temperature lower than 36.0 °C, which can contribute to many adverse events. The special physiological characteristics in children further increase the incidence of IPH. Therefore, it is very important to perform effective perioperative warming measures for children. Traditional passive warming measures with additional layers have limited thermal insulation effects. Active warming measures might be the better choice, and most measures have achieved good effects in adults. This study combines a variety of active warming measures to propose perioperative active warming strategies and aims to verify the feasibility and thermal insulation effects of perioperative active warming strategies in children.

Methods

This study is a multicentre, prospective, randomized controlled trial. From August 2022 to July 2024, 400 paediatric patients undergoing elective surgery will be recruited in four centres and randomly divided into the active warming strategies group and control group at a ratio of 1:1. The primary outcome is the perioperative cumulative hypothermia effect value (Σ ΔTi × Δti, i = 1…, n). Multiple complications covering the anaesthesia recovery period and postoperative hospitalization will be considered as secondary outcomes to comprehensively analyse the prognosis.

Trial registration

ClinicalTrials.gov identifier: ChiCTR2200062168. Registered on July 26th, 2022. Registered with the name of "Perioperative Active Warming Strategies in Children: A multicenter, prospective, randomized controlled trial". URL:http://www.chictr.org.cn/showproj.aspx?proj=172778.

The Effects of Active Warming on Core Body Temperature and Thermal Comfort in Patients After Transurethral Resection of the Prostate: A Randomized Clinical Trial

Prevention and treatment of hypothermia by active warming in perioperative period care is recommended but scientific evidence of its effectiveness in a clinical setting is scarce. The purpose of this study was to determine the effects of warmed intravenous fluids (WIVF) on the core body temperature and the patients' thermal comfort. Baseline data of 105 male patients undergoing TUR-P surgery and bladder irrigation were analyzed. The experimental group was warmed using active WIVF, and the control group's routine care was conducted using a cotton blanket. Body temperature was higher in patients in the experimental group than those in the control group. Repeated measures Manova revealed significantly different core temperature changes between groups (F = 34.446, p = .001). The thermal comfort scores were also higher in the experimental group than in the control group (x² = 203.552, p = .001). The findings indicated that WIVF can enhance body temperature and improve the thermal comfort of patients.

Comparison of the Effect of Forced-air Warming and Warmed Intravenous Fluid on the Comfort and Prevention of Shivering After Spinal Anesthesia in Patients Undergoing Orthopedic Surgery

PURPOSE

This study aimed to compare the effect of forced-air warming and warmed intravenous fluid on the comfort and prevention of shivering after spinal anesthesia in patients undergoing orthopaedic surgery.

DESIGN

Randomized controlled clinical trial.

METHODS

A total of 120 patients were randomly divided into three groups: forced-air warming (38°C), warmed intravenous fluid (37°C), and the control group. Patients' comfort and severity of shivering were measured and recorded five times (immediately and 15 minutes after spinal anesthesia, end of the surgery, time of entrance to the recovery room, and 15 minutes after entering the recovery room), and compared with each other.

FINDINGS

There was a significant difference between the three groups in terms of comfort at all points of evaluation times (P < .001). The comfort score in the control group was significantly higher than the two intervention groups (P < .001). Moreover, the comfort score in the warmed intravenous fluid group was significantly higher than the forced-air warming group (P < .001). In addition, there was a significant difference in shivering severity between the three groups at the end of the surgery, entrance to the recovery room, and 15 minutes after surgery (P < .001). The majority of patients in the forced-air warming group (90%) had no shivering at all three times, while the warmed IV fluid and control groups was 65% and 30% respectively.

CONCLUSIONS

Non-pharmacological methods such as forced-air warming and warmed intravenous fluid can provide comfort and prevent shivering in orthopaedic patients undergoing spinal anesthesia. However, the use of forced-air warming is more effective than warmed intravenous fluid in providing comfort and preventing shivering in these patients. It is recommended that these methods be used in the operating room to provide comfort and prevent shivering in these patients.

Application of Care Bundles in Postanesthesia Recovery for Elderly Patients with Colorectal Cancer

Objective

Based on the postanesthesia recovery procedure for elderly patients with colorectal cancer, a care bundle program was conducted to validate its effectiveness.

Method

According to the characteristics of elderly patients with colorectal cancer, five measures including respiratory management, circulatory stability, pain assessment, body temperature monitoring, and internal environment stability were integrated into one bundle. Postanesthesia care unit (PACU) care bundle program for elderly patients was developed and used to improve recovery care. The monitoring data of the pre-PACB group given care bundles were collected and compared with the data of the post-PACB group who were given conventional recovery care.

Result

222 patients in post-PACB group had shorter intubation time than 291 patients in pre-PACB group (37.7 ± 24.4 min vs. 42.1 ± 23.3 min, P < 0.05). The length of stay in PACU was longer in pre-PACB group (89.9 ± 33.5 min vs. 81.6 ± 31.1 min, P < 0.05). More adverse events were found in the post-PACB group than in the pre-PACB group (72.1% vs. 34.0%).

Conclusion

After general anesthesia of patients with colorectal cancer, the application of the care bundles can improve the quality of recovery, shorten the intubation time and the length of stay in PACU, and reduce the complications caused by anesthesia.

Effect of forced-air warming system in prevention of postoperative hypothermia in elderly patients: A Prospective controlled trial

BACKGROUND

Postoperative hypothermia in elderly patients is a well-known serious complication as it impairs wound healing, induces coagulopathy, increases the risk of blood loss, enhances oxygen consumption, and precipitates cardiac arrhythmias. We conducted this randomized controlled trial to evaluate the effect of a forced-air warming system on rewarming elderly patients undergoing total knee or hip arthroplasty.

METHODS

We recruited 243 elderly patients undergoing total knee or hip arthroplasty between May and December 2016. They were divided into three groups according to a computer-generated randomization table: group C (n = 78, rewarmed with only a regular blanket), group F1 (n = 82, rewarmed with a forced-air warming system set at 38°C), and group F2 (n = 83, rewarmed with a forced-air warming system set at 42°C). The nasopharyngeal temperature was recorded every 5 min for the first half hour, then every 10 min up to the end of the PACU (postanesthesia care unit) stay. The primary outcome was the rewarming time. The rewarming rate, increase in nasopharyngeal temperature (compared to the start of rewarming), hemodynamics, recovery time, and incidences of adverse effects were recorded.

RESULTS

No significant differences were found among the three groups in terms of the baseline clinical characteristics, use of narcotic drugs, intraoperative temperature, and hemodynamics (P > .05). Compared with the elderly patients in groups C and F1, both the heart rate and mean arterial pressure of those in group F2 were significantly increased 20 min after arrival at the PACU (P < .05). Patients in group F2 had the shortest rewarming time (35.89 ± 6.45 min, P < .001), highest rewarming efficiency (0.028 ± 0.001°C/min, P < .001), and fastest increased nasopharyngeal temperature among the three groups. Moreover, the elderly patients in group F2 had lower incidences of arrhythmia and shivering (P < .05).

CONCLUSIONS

The use of a forced-air warming system set at 42°C was shown to be the most effective way of rewarming elderly patients with postoperative hypothermia.

Clinical practice guideline. Unintentional perioperative hypothermia

The importance of the safety of our patients in the surgical theatre, has driven many projects. The majority of them aimed at better control and clinical performance; mainly of the variables that intervene or modulate the results of surgical procedures, and have a direct relationship with them. The Spanish Society of Anesthesiology, Critical Care and Therapeutic Pain (SEDAR), maintains a constant concern for a variable that clearly determines the outcomes of our clinical processes, "unintentional hypothermia" that develops in all patients undergoing an anesthetic or surgical procedure. SEDAR has promoted, in collaboration with other scientific Societies and patient Associations, the elaboration of this clinical practice guideline, which aims to answer clinical questions not yet resolved and for which, up to now, there are no documents based in the best scientific evidence available. With GRADE methodology and technical assistance from the Ibero-American Cochrane Collaboration office, this clinical practice guideline presents three recommendations (weak in favor) for active heating methods for the prevention of hypothermia (skin, fluid or gas); three for the prioritization of strategies for the prevention of hypothermia (too weak in favor and one strongly in favor); two of preheating strategies prior to anesthetic induction (both weak in favor); and two for research.

Efficacy of prophylactic epidural ketamine for reducing shivering in patients undergoing caesarean section with combined spinal-epidural anesthesia

Intravenous ketamine is known to inhibit postoperative shivering; however, at present, there has been little research on whether this effect may be achieved with epidural application. The aim of the present study was to evaluate the efficacy and safety of epidural ketamine as a prophylactic agent to prevent shivering in patients undergoing caesarean section during combined spinal-epidural anesthesia. A prospective, randomized, double-blind study was performed. A total of 60 patients who were undergoing elective caesarean section under combined spinal-epidural anesthesia and had an American Society of Anesthesiologists physical status of I or II were recruited. Patients were randomly allocated to group S (epidural administration of normal saline; n=30) or group K (epidural ketamine 0.5 mg/kg; n=30). An investigator, blinded to the treatment groups, graded postoperative shivering using a 4-point scale and postoperative sedation on a 5-point scale. Operative time, hemodynamic changes and side effects, including hypotension, bradycardia, nausea and hallucinations, were recorded. The results demonstrated that patients' characteristics were not significantly different between groups. Heart rate, peripheral capillary oxygen saturation (SpO₂) values and Apgar scores at 1 and 5 min also did not differ significantly between groups. The incidence and severity of shivering in group K was significantly reduced compared with group S (P<0.05). The mean arterial pressure (MAP) was significantly different in groups S and K compared with baseline values at 10, 30 and 60 min (P<0.05). Furthermore, MAP values at 10, 30 and 60 min were significantly higher in group K compared with in group S (P<0.05). The results of the present study suggest that epidural administration of prophylactic low-dose ketamine may be an effective strategy for preventing postoperative shivering.

Perioperative Care of Elderly Surgical Outpatients

The ambulatory setting offers potential advantages for elderly patients undergoing elective surgery due to the advancement in both surgical and anesthetic techniques resulting in quicker recovery times, fewer complications, higher patient satisfaction, and reduced costs of care. This review article aims to provide a practical guide to anesthetic management of elderly outpatients. Important considerations in the preoperative evaluation of elderly outpatients with co-existing diseases, as well as the advantages and disadvantages of different anesthetic techniques on a procedural-specific basis, and recommendations regarding the management of common postoperative complications (e.g., pain, postoperative nausea and vomiting [PONV], delirium and cognitive dysfunction, and gastrointestinal dysfunction) are discussed. The role of anesthesiologists as perioperative physicians is important for optimizing surgical outcomes for elderly patients undergoing ambulatory surgery. The implementation of high-quality, evidence-based perioperative care programs for the elderly on an ambulatory basis has assumed increased importance. Optimal management of perioperative pain using opioid-sparing multimodal analgesic techniques and preventing PONV using prophylactic antiemetics are key elements for achieving enhanced recovery after surgery.

Effect of an electric blanket plus a forced-air warming system for children with postoperative hypothermia: A randomized controlled trial

BACKGROUND

Postoperative hypothermia in children in postanesthesia care unit (PACU) is a well-known serious complication as it increases the risk of blood loss, wound infections, and cardiac arrhythmias. We conducted this prospective randomized controlled trial to evaluate the effect of an electric blanket plus a forced-air warming system on rewarming in children with postoperative hypothermia.

METHODS

We recruited 346 children (aged < 3 years) who were admitted to a PACU after surgery and diagnosed with hypothermia between March and August 2016. They were randomly divided into 3 groups: group C (n = 108, rewarmed with only a regular blanket), group E (n = 123, rewarmed with a regular blanket plus an electric blanket), and group EF (n = 115, rewarmed with an electric blanket plus a forced-air warming system). From the beginning of rewarming, the rectal temperature was recorded every 5 minutes for the first half hour, then every 10 minutes up to when the patient left the PACU. The primary outcome was the rewarming time of children (from the beginning of rewarming to recovery of normothermia). The rewarming rate, increase in temperature (compared with the beginning of rewarming), hemodynamics, recovery time, and incidences of adverse effects were recorded.

RESULTS

There were no significant differences among the 3 groups in terms of the baseline clinical characteristics, use of narcotic drugs, intraoperative temperature, and hemodynamics (P > .05). Compared with the children in groups C and E, both the heart rate and mean arterial pressure of those in group EF were significantly increased after 10 minutes of arriving at the PACU (P < .05). Children in the EF group had the shortest rewarming time (35.61 ± 16.45 minutes, P < .001) and highest rewarming efficiency (0.028 ± 0.001 °C/min, P < .001), while there was no evidence of a difference in increased rectal temperature among the 3 groups. Children in the EF group had lower incidences of arrhythmia, shivering, nausea, and vomiting (P < .05).

CONCLUSION

The combination of an electric blanket and a forced-air warming system was shown to be an effective rewarming method for children with postoperative hypothermia.

Inadvertent Hypothermia After Procedural Sedation and Analgesia in a Cardiac Catheterization Laboratory: A Prospective Observational Study

OBJECTIVES

To identify the prevalence of and risk factors for inadvertent hypothermia after procedures performed with procedural sedation and analgesia in a cardiac catheterization laboratory.

DESIGN

A single-center, prospective observational study.

SETTING

A tertiary-care private hospital in Australia.

PARTICIPANTS

399 patients undergoing elective procedures with procedural sedation and analgesia were included. Propofol infusions were used when an anesthesiologist was present. Otherwise, bolus doses of either midazolam or fentanyl or a combination of these medications was used.

INTERVENTIONS

None

MEASUREMENTS AND MAIN RESULTS

Hypothermia was defined as a temperature<36.0°C. Multivariate logistic regression was used to identify risk factors. Hypothermia was present after 23.3% (n = 93; 95% confidence interval [CI] 19.2%-27.4%) of 399 procedures. Sedative regimens with the highest prevalence of hypothermia were any regimen that included propofol (n = 35; 40.2%; 95% CI 29.9%-50.5%) and the use of fentanyl combined with midazolam (n = 23; 20.3%; 95% CI 12.9%-27.7%). Difference in mean temperature from pre-procedure to post-procedure was -0.27°C (standard deviation 0.45). Receiving propofol (odds ratio [OR] 4.6 95% CI 2.5-8.6), percutaneous coronary intervention (OR 3.2; 95% CI 1.7-5.9), body mass index<25 (OR 2.5; 95% CI 1.4-4.4) and being hypothermic prior to the procedure (OR 4.9; 95% CI 2.3-10.8) were independent predictors of post-procedural hypothermia.

CONCLUSIONS

A moderate prevalence of hypothermia was observed. The small absolute change in temperature observed may not be a clinically important amount. More research is needed to increase confidence in the authors' estimates of hypothermia in sedated patients and its impact on clinical outcomes.