Thermal care in the perioperative period

Effects of Perioperative Hypothermia on Extubation, Recovery Time, and Postoperative Shivering in Breast Surgery

Women undergoing breast surgery seem to be under the risk for hypothermia (central body temperature <36°) due to the uncertainty caused by the preoperative preparation time and the variety of operations, leading to neglect of warming precautions. The study examines the perioperative hypothermia (PH) in breast surgery and the relationships between the depth of decrease in body temperature and individual or clinical variables. This prospective, cross-sectional, observational study includes 120 female patients 18-65 years of age who were given general anesthesia for breast surgery. The incidence of hypothermia was 68.1%. The given patients were discriminated as body temperature <36°, hypothermia was significantly related with lower weight, body mass index, American Society of Anesthesiology (ASA) score, baseline body temperatures, higher extubation, and recovery times. When patients' temperature decreases by >1 or 1.5°, lower age and longer durations of operation and anesthesia were also significant variables. The incidence of shivering is quite high at temperatures below 36°C or at 1 and 1.5°C reductions from baseline (72.7%, 84%, 94.1%, respectively). Body temperature changes of the patients had no effect on nausea-vomiting and pain scores. It turned out that the incidence of PH and shivering is high in women who underwent breast surgery. We think that the depth of decrease in body temperature should be taken into account when evaluating the predictors or clinical consequences of hypothermia, except for the 36°C limit for body temperature.

A Warm Air Blanket is Superior to a Heated Mattress in Preventing Perioperative Hypothermia in Orthopedic Arthroplasties, a Time-Series Analyses

BACKGROUND

Hypothermia is a common perioperative problem that can lead to severe complications. We evaluated whether a heated mattress (HM) is superior to a warm air blanket (WA) in preventing perioperative hypothermia in patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA).

METHODS

A retrospective cohort study was performed in a teaching hospital and data were collected for all patients undergoing THA or TKA between January 1, 2015 and May 1, 2022. We used logistic and linear regressions to analyze hypothermia occurrence and important complications. Results were adjusted for confounders and time, and was present in all subgroups and after imputation of missing data.

RESULTS

In total, 4,683 of 5,497 patients had information on type of heating. We found more perioperative hypothermia in patients treated with an HM compared to a WA for both THA (odds ratio-adjusted 1.42 [1.0 to 1.6] P = .06) and TKA (odds ratio-adjusted 2.10 [1.5 to 3.0] P < .01). There was no difference in postoperative infections between groups (all between 0.5% and 1.3%). Patients who had an HM significantly stayed longer in the postoperative ward (a mean difference of 4 [TKA] to 6 [THA] minutes, P < .01), but there was no difference in hospital stay.

CONCLUSION

A WA is superior compared to an HM in preventing perioperative hypothermia, with no increased risk of complications. Patients who have an HM stayed longer at the postoperative ward, potentially because of higher hypothermia rates. Therefore, it is suggested to use a WA instead of an HM.

Dexamethasone with aggressive warming facilitates pain reduction, reduced blood loss, and quicker recovery after total hip arthroplasty

This study aimed to evaluate the optimal frequency of dexamethasone (DEX) administration and the efficacy of DEX with aggressive warming in total hip arthroplasty (THA), which remains unclear. A total of 150 patients were treated with DEX (10 mg) once before and once or twice after surgery with or without intraoperative aggressive warming. On postoperative day 3, the dynamic visual analogue scale scores and C-reactive protein (CRP) and interleukin-6 (IL-6) levels in participants administered with DEX twice after surgery were significantly lower than those who did not receive the second dose. The range of motion (ROM), postoperative fatigue based on Identity-Consequence-Fatigue Scale, average temperature at different stages, intraoperative blood loss, and postoperative drainage volume in patients who were subjected to warming were significantly higher than those who were not. The degree of satisfaction was also higher in the patients who received both second dose and warming than those who received neither. No differences in complications were observed based on the treatments. An additional dose of DEX at 48 h post-surgery has short-term advantages in terms of analgesia, anti-inflammatory effects, and accelerated rehabilitation after THA. DEX combined with aggressive warming further optimises short-term ROM and fatigue and improves the degree of satisfaction.Clinical trial was registered in the International Clinical Trial Registry, and the date of registration is 2/12/2020 (ChiCTR2000040560).

Inaccuracy of surgical irrigation fluid temperature hand assessment

INTRODUCTION

Fluids are often used for irrigation during surgical procedures. The temperature of the fluid directly affects the exposed tissue and body temperature. The recommended practice is to use euthermic fluids to be homeostatic and optimise patient care. Hand checking the fluid temperature by surgeons and scrub practitioners is the commonly used method. This subjective measurement leaves room for error and can lead to inaccuracies. The purpose of the study is to assess the accuracy of the currently used method of checking irrigation fluids temperature by hand immersion.

METHOD

Two sets of fluids were prepared. One was made at 37°C and the other was 30°C. Participants immersed their hands in the containers and then report if each of the two sets is (1) appropriately warm for irrigation, (2) too cool and (3) too warm. Data were collected and interpreted.

RESULTS

Results showed that about half of participants in our study perceived normal physiologic fluid temperature as too hot for use in irrigation, 30°C fluid was perceived as appropriate and physiologic by about a quarter of participants.

CONCLUSIONS

Perception of surgical irrigation fluid temperature by hand immersion is inaccurate. Standard objective methods of measuring the temperature are recommended.

Self-warming blankets versus active warming by forced-air devices for preventing hypothermia: A systematic review and meta-analysis

BACKGROUND

Unintended perioperative hypothermia is a significant complication for patients undergoing anesthesia. Different measures are routinely undertaken to prevent hypothermia and its consequences. The evidence comparing the impact of self-warming blankets and forced-air warming is scarce. Therefore, this meta-analysis aimed to evaluate the efficacy of self-warming blankets compared to forced-air devices regarding the incidence of perioperative hypothermia.

METHODS

We searched the Web of Science, Cochrane Central Register of Controlled Trials, PubMed, and Scopus for relevant studies from inception until December 2022. We included comparative studies with patients allocated to undergo warming using a self-warming blanket or forced air warming. All concerned outcomes were pooled as odds ratios or mean differences (MDs) in the meta-analysis models using Review Manager (RevMan version 5.4).

RESULTS

Our results from 8 studies (597 patients) favored self-warming blankets over forced-air devices in terms of core temperature at 120 and 180 minutes after induction of general anesthesia (MD = 0.33, 95% confidence interval [CI] [0.14-0.51], P = .0006), (MD = 0.62, 95% CI [0.09-1.14], P = .02), respectively. However, the overall effect did not favor either of the 2 groups for the incidence of hypothermia (odds ratio = 0.69, 95% CI [0.18-2.62]).

CONCLUSION

Ultimately, self-warming blankets have a more significant effect than forced-air warming systems in terms of maintaining normothermia of core temperature after induction anesthesia. However, the present evidence is not enough to verify the efficacy of the 2 warming techniques in the incidence of hypothermia. Further studies with large sample sizes are recommended.

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).

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.

Health Technology Assessment for the Prevention of Peri-Operative Hypothermia: Evaluation of the Correct Use of Forced-Air Warming Systems in an Italian Hospital

This study investigates the implications of using a system for the maintenance of normothermia in the treatment of patients undergoing surgery, determining whether the FAW (Forced-Air Warming) systems are more effective and efficient than the non-application of appropriate protocols (No Technology). We conducted Health Technology Assessment (HTA) analysis, using both real-world data and the data derived from literature, assuming the point of view of a medium-large hospital. The literature demonstrated that Inadvertent Perioperative Hypothermia (IPH) determines adverse events, such as surgical site infection (FAW: 3% vs. No Technology: 12%), cardiac events (FAW: 3.5% vs. No Technology: 7.6%) or the need for blood transfusions (FAW: 6.2% vs. No Technology: 7.4%). The correct use of FAW allows a medium saving of 16% per patient to be achieved, compared to the non-use of devices. The Cost Effectiveness Value (CEV) is lower in the hypothesis of FAW: it enables a higher efficacy level with a contextual optimization of patients' path costs. The social cost is reduced by around 30% and the overall hospital days are reduced by between 15% and 26%. The qualitative analyses confirmed the results. In conclusion, the evidence-based information underlines the advantages of the proper use of FAW systems in the prevention of accidental peri-operative hypothermia for patients undergoing surgery.

Development of local guidelines to prevent perioperative hypothermia in children: a prospective observational cohort study

PURPOSE

Perioperative hypothermia (PH) is defined as core body temperature < 36°C during the perioperative period. The incidence of PH is not well established in children because of variations in perioperative temperature monitoring and control measures. We sought to 1) establish the incidence of pediatric PH, 2) assess its adverse outcomes, and 3) identify risk factors in our pediatric population to develop local guidelines for prevention of PH.

METHODS

We conducted a prospective observational cohort study at a single tertiary hospital (KK Women's and Children's Hospital, Singapore) from June 2017 to December 2017 based on existing institutional practice. We recruited patients aged ≤ 16 yr undergoing surgery and determined the incidence and adverse outcomes of hypothermia. We identified risk factors for PH using univariate and multiple logistic regression analysis and used these to develop local guidelines.

RESULTS

Of 1,766 patients analyzed, 213 (12.1%; 95% confidence interval, 10.6 to 13.7) developed PH. Among these cases of PH, only 4.5% would have been detected by a single measurement in the postanesthesia care unit (PACU). Adverse outcomes included a longer stay in the PACU (47 vs 39 min; P < 0.01), a higher incidence of shivering (7.1 vs 2.6%; P = 0.01), and more discomfort (3.8 vs 1.4%; P = 0.02) compared with normothermic patients. Risk factors for PH included preoperative temperature < 36°C, surgery duration > 60 min, ambient operating room temperature < 23.0°C, and several "high-risk" surgeries. Guidelines were developed based on these risk factors and customized according to clinical and workflow considerations.

CONCLUSIONS

Perioperative hypothermia was a common problem in our pediatric population and was associated with significant adverse outcomes. Guidelines developed based on risk factors identified in the local context can facilitate workflow and implementation within the institution.

Novel ultrashort-acting benzodiazepine remimazolam lowers shivering threshold in rabbits

Shivering after surgery or during therapeutic hypothermia can lead to serious complications, such as myocardial infarction and respiratory failure. Although several anesthetics and opioids are shown to have anti-shivering effects, their sedative and respiratory side effects dampen the usefulness of these drugs for the prevention of shivering. In the present study, we explored the potential of a novel ultrashort-acting benzodiazepine, remimazolam, in the prevention of shivering using a rabbit model of hypothermia. Adult male Japanese white rabbits were anesthetized with isoflurane. The rabbits received saline (control), remimazolam (either 0.1 or 1 mg/kg/h), or remimazolam + flumazenil, a selective γ-aminobutyric acid (GABA) type A receptor antagonist (n = 6 each). Thirty minutes after discontinuation of the drugs, cooling was initiated by perfusing 10°C water via a plastic tube positioned in the colon until the animal shivered. Core body temperature and hemodynamic and physiological parameters were recorded. Remimazolam at 1 mg/kg/h significantly lowered the core temperature change during shivering (−2.50 ± 0.20°C vs. control: −1.00 ± 0.12°C, p = 0.0009). The effect of 1 mg/kg/h remimazolam on the core temperature change was abolished by flumazenil administration (−0.94 ± 0.16°C vs. control: −1.00 ± 0.12°C, p = 0.996). Most of the hemodynamic and physiological parameters did not differ significantly among groups during cooling. Remimazolam at a clinically relevant dose successfully suppressed shivering in rabbits via the GABA pathway even after its anesthetic effects likely disappeared. Remimazolam may have the potential to prevent shivering in patients undergoing surgery or therapeutic hypothermia.

Enhanced recovery after surgery (ERAS) protocol in spine surgery

Enhanced recovery after surgery (ERAS) protocols are a set of interventions which are carried out in the preoperative and perioperative period. They are aimed to decrease the harmful effects of surgery on the body and help the patient recover better post-surgery. The effectiveness of ERAS has been well established in various other surgical specialities. Earlier spine surgery was thought to be very complex for application of ERAS protocols. However, this has changed over the last decade with (ERAS) protocols gaining widespread popularity in spine surgery. Initial studies involving ERAS in spine surgery were limited to lumbar spine. However, over the years the horizon of ERAS has expanded to include anterior cervical surgeries, spine deformity, spinal tumors and spine surgery in the elderly. ERAS has been shown to reduce the length of hospital stay, overall hospital costs, opioid consumption in perioperative and postoperative period and to lower complication rates in spine surgery. In this narrative review, we discuss various aspects of ERAS in spine surgery including the benefits of ERAS in spine surgery, the various components of preoperative, intraoperative and postoperative measures of ERAS protocol.

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.

Effects of a Heated Anesthesia Breathing Circuit on Body Temperature in Anesthetized Rhesus Macaques (Macaca mulatta)

This study evaluated the effects of using a heated anesthesia breathing circuit in addition to forced-air warming on body temperature in anesthetized rhesus macaques as compared with forced-air warming alone. Hypothermia is a common perianesthetic and intraoperative complication that can increase the risk of negative outcomes. Body heat is lost through 4 mechanisms during anesthesia: radiation, conduction, convection, and evaporation. Typical warming methods such as forced-air warming devices, conductive heating pads, and heated surgical tables only influence radiative and conductive mechanisms of heat loss. A commercially available heated breathing circuit that delivers gas warmed to 104 °F can easily be integrated into an anesthesia machine. We hypothesized that heating the inspired anesthetic gas to address the evaporative mechanism of heat loss would result in higher body temperature during anesthesia in rhesus macaques. Body temperatures were measured at 5-min intervals in a group of 10 adult male rhesus macaques during 2 anesthetic events: one with a heated anesthesia breathing circuit in addition to forced-air warming, and one with forced-air warming alone. The addition of a heated breathing circuit had a significant positive effect on perianesthetic body temperature, with a faster return to baseline temperature, earlier nadir of initial drop in body temperature, and higher body temperatures during a 2-h anesthetic procedure. Use of a heated anesthesia breathing circuit should be considered as a significant refinement to thermal support during macaque anesthesia, especially for procedures lasting longer than one hour.

Day case unicompartmental knee replacement: An update of the Torbay experience

BACKGROUND

Hospitals throughout the United Kingdom face significant challenges in regards to inpatient bed capacity, leading to growing interest in day case arthroplasty. Day case Unicompartmental Knee Replacement (UKR) has been offered within our unit since 2010, with successive evaluations of pathway outcomes performed in 2011 and 2015. Since then, our day case UKR pathway has expanded. This study aims to evaluate the safety, efficiency and patient satisfaction with this expanded pathway.

METHODS

Data was prospectively collected for all patients undergoing a UKR between January 2017 and August 2019. Data collected included the pathway planned, date of admission, date of discharge and re-admissions to hospital within 30 days of surgery. Patient satisfaction was evaluated via a follow-up questionnaire.

RESULTS

109 patients underwent a UKR between January 2017 and August 2019. 83 patients (76%) were planned through the day case pathway. 63 patients were successfully discharged on the day of surgery. One day case pathway and two inpatient pathway patients were re-admitted within 30 days of surgery with medical conditions. A high level of patient satisfaction with our day case pathway was identified.

CONCLUSION

UKR with planned discharge on the day of surgery is possible for a large proportion of patients provided that robust pathway and protocol design is undertaken. Following 10 years' experience, our day case UKR pathway has increasingly become the default for the majority of our patients. We report high patient satisfaction and low 30-day re-admission rates. However, 100% success rate for day of surgery discharge remains challenging.

Consensus statement for perioperative care in lumbar spinal fusion: Enhanced Recovery After Surgery (ERAS®) Society recommendations

BACKGROUND

Enhanced Recovery After Surgery (ERAS) evidence-based protocols for perioperative care have led to improvements in outcomes in numerous surgical areas, through multimodal optimization of patient pathway, reduction of complications, improved patient experience and reduction in the length of stay. ERAS represent a relatively new paradigm in spine surgery.

PURPOSE

This multidisciplinary consensus review summarizes the literature and proposes recommendations for the perioperative care of patients undergoing lumbar fusion surgery with an ERAS program.

STUDY DESIGN

This is a review article.

METHODS

Under the impetus of the ERAS® society, a multidisciplinary guideline development group was constituted by bringing together international experts involved in the practice of ERAS and spine surgery. This group identified 22 ERAS items for lumbar fusion. A systematic search in the English language was performed in MEDLINE, Embase, and Cochrane Central Register of Controlled Trials. Systematic reviews, randomized controlled trials, and cohort studies were included, and the evidence was graded according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. Consensus recommendation was reached by the group after a critical appraisal of the literature.

RESULTS

Two hundred fifty-six articles were included to develop the consensus statements for 22 ERAS items; one ERAS item (prehabilitation) was excluded from the final summary due to very poor quality and conflicting evidence in lumbar spinal fusion. From these remaining 21 ERAS items, 28 recommendations were included. All recommendations on ERAS protocol items are based on the best available evidence. These included nine preoperative, eleven intraoperative, and six postoperative recommendations. They span topics from preoperative patient education and nutritional evaluation, intraoperative anesthetic and surgical techniques, and postoperative multimodal analgesic strategies. The level of evidence for the use of each recommendation is presented.

CONCLUSION

Based on the best evidence available for each ERAS item within the multidisciplinary perioperative care pathways, the ERAS® Society presents this comprehensive consensus review for perioperative care in lumbar fusion.

Effect of perioperative hypothermia on surgical site infection in abdominal surgery: A prospective cohort study

AIM

To estimate the incidence rates of surgical site infection and identify the independent effect of perioperative hypothermia on the incidence of this type of infection in patients undergoing abdominal surgery.

BACKGROUND

Around the world, surgical site infection is a frequent complication in surgical patients, mainly causing increased morbidity and mortality rates and health service costs.

DESIGN

A prospective cohort study.

METHODS

The 484 patients were recruited from a large private philanthropic hospital in the state of São Paulo, Brazil, from July 2016 to May 2017. Crude and adjusted models were constructed for the hypothermia indicators to assess the effect of this exposure on surgical site infection.

RESULTS

The incidence rate of surgical site infection was 20.25% (n = 98). The attributable fraction to exposed to hypothermia was >40%. A greater probability of developing surgical site infection (relative risk = 1.89) was found for patients who experienced body temperatures <36.0°C (from entry time into the operating room until the end of the surgery) for more than five hypothermic episodes or longer than 75 min.

CONCLUSION

Perioperative hypothermia was an independent risk factor for surgical site infection.

SUMMARY STATEMENT

What is already known about this topic? Around the world, surgical site infection is a complication that leads to damage to the patient and increased costs for the health services. Despite recent advances in surgical techniques, surgical site infection remains one of the most frequent complications in abdominal surgery. Perioperative hypothermia can increase the incidence rates of surgical site infection. There is evidence that perioperative hypothermia is associated with surgical site infection in abdominal surgery, but most studies were conducted in developed countries using retrospective designs. What this paper adds? Perioperative hypothermia was identified as an independent risk factor for surgical site infection in patients undergoing abdominal surgery. The attributable fraction to the exposed indicated that, if the main exposure of interest (perioperative hypothermia) could be prevented during surgical anaesthetic procedures, more than 40% of surgical site infection cases would be avoided. The classification of the American Society of Anaesthesiologists was independently associated with the surgical site infection and presented a dose-response effect among its categories. Spinal anaesthesia served as an independent protective factor for surgical site infection. The implications of this paper: The health service managers need to be aware of potential cost-savings associated with perioperative hypothermia prevention as a measure to reduce the incidence of surgical site infection. During the perioperative period, health professionals need to implement effective measures to maintain patients' normothermia, promoting improved care and surgical patient safety. In this context, the nurse's role is fundamental. Future research projects using a prospective design and developed to address the reality of developing countries can contribute to the strengthening and consistency of the findings with a view to a global understanding of the surgical site infection problem.

Central Neural Circuits Orchestrating Thermogenesis, Sleep-Wakefulness States and General Anesthesia States

Great progress has been made in specifically identifying the central neural circuits (CNCs) of the core body temperature (Tcore), sleep-wakefulness states (SWs), and general anesthesia states (GAs), mainly utilizing optogenetic or chemogenetic manipulations. We summarize the neuronal populations and neural pathways of these three CNCs, which gives evidence for the orchestration within these three CNCs, and the integrative regulation of these three CNCs by different environmental light signals. We also outline some transient receptor potential (TRP) channels that function in the CNCs-Tcore and are modulated by some general anesthetics, which makes TRP channels possible targets for addressing the general-anesthetics-induced-hypothermia (GAIH). We suggest this review will provide new orientations for further consummating these CNCs and elucidating the central mechanisms of GAIH.

Perioperative body temperature maintenance and occurrence of surgical site infection: A systematic review with meta-analysis

BACKGROUND

Current guidelines recommend perioperative warming as one of the strategies to prevent surgical site infection, although there are gaps in the knowledge produced on this issue.

AIM

Assess the efficacy of active warming methods to maintain perioperative patients' body temperature and its effect on the occurrence of surgical site infection.

METHODS

A systematic review with meta-analysis was carried out. PubMed, CINAHL, LiLACS, CENTRAL, and EMBASE databases were searched.

FINDINGS

Of the 956 publications identified, 9 studies were selected for quantitative synthesis and 6 for the meta-analysis. The forced-air warming system was investigated in 8 studies. The generated evidence indicated that the use of an active warming method could maintain higher average body temperature as well as could decrease the surgical site infection incidence. Exposure of the patient to temperatures below 36°C in the perioperative period increased the chances of developing this type of infection. The meta-analysis indicated that the association between perioperative active warming methods compared with others to reduce the chances of developing surgical site infection remains unclear (odds ratio = e^-3.59 = 2.718^-0.59 = 0.552, 95% confidence interval (odds ratio) = (0.269-1.135), P = 0.106 I² = 54.34%).

CONCLUSIONS

The employment of an active warming method is effective to maintain higher averages of body temperature. However, more randomized clinical trials are needed to assess the efficacy of that intervention to prevent surgical site infection.

Guidelines in Practice: Hypothermia Prevention

All patients are at risk for unplanned hypothermia in the perioperative practice setting. Adverse outcomes attributed to hypothermia include myocardial events, surgical site infections, poor wound healing, increased blood loss, and prolonged postanesthesia care unit stays. The AORN "Guideline for prevention of hypothermia" includes recommendations for measuring the patient's body temperature, selecting methods for prevention of unplanned hypothermia, and implementing the selected insulation and warming interventions. This article discusses guideline recommendations related to using a consistent temperature measurement method through all phases of perioperative care, assessing risk for hypothermia in all patients, and prewarming perioperative patients. A scenario provides an example in which an interdisciplinary facility team uses a gap analysis and a risk assessment to determine the process for implementing recommendations from this guideline. Perioperative RNs should review the entire guideline for additional information and for guidance when creating and updating policies and procedures related to unplanned hypothermia.

The Effect of Active Warming on Postoperative Hypothermia on Body Temperature and Thermal Comfort: A Randomized Controlled Trial

PURPOSE

The purpose of this study was to determine the effect of active warming method in temperature control and thermal comfort in hypothermia after surgery.

DESIGN

A randomized controlled trial.

METHODS

The study sample consisted of 64 male and female postanesthesia care unit and intensive care unit neurosurgery postoperative inpatients. The experimental group was warmed using the active warming method, and the control group's routine care was continued via a cotton blanket. Patients were warmed until their tympanic body temperature reached 37°C.

FINDINGS

The time needed to adequately warm patients was approximately twice as short in those who received active warming as compared with the control group. The perception of thermal comfort was significantly higher in the first hour in patients who received the active warming method (P < .05).

CONCLUSIONS

The active warming method resulted in a shorter time to warming in hypothermia after surgery and an increase in the perception of thermal comfort and body temperature.

Intraoperative Irrigation: Fluid Administration and Management Amidst Conflicting Evidence

Surgeons use irrigation during open cavity procedures to improve their view of the patient's anatomy and to reduce the patient's risk of infection. However, there are no standard guidelines that recommend a specific type of fluid, additive, or volume of irrigation to use during open procedures. Intraoperative hypothermia can occur if irrigation fluids have not been warmed or have cooled before use, causing adverse patient outcomes. In addition, failing to manage (eg, measure and document) fluid volume accurately may affect clinical decision making and cause other complications. Perioperative personnel should evaluate new technologies that may improve the efficiency and accuracy of irrigation temperature and volume measurements. More research is needed to develop standardized practice guidelines for intraoperative irrigation and fluid management.

Effects of postoperative active warming and early exercise on postoperative body temperature distribution: Non-blinded and randomized controlled trial

AIM

We tested a hypothesis that postoperative active warming and/or arm leg stretches reduce the difference between core and skin temperatures (primary variable) improving the peripheral circulation immediately after major abdominal surgery.

METHODS

Fifty-one patients undergoing major abdominal surgeries were randomly assigned to receive one of three interventions immediately after surgery; routine care (control group), mild intermittent exercise on the bed (exercise group), and forced-air warming (warming group). Core and skin temperatures and perfusion index were continuously measured from anesthesia induction to 12 h after arrival at the ward.

RESULTS

Core body temperature was maintained over 37°C with a relatively greater gap between core and skin temperatures over 1°C and reduced perfusion index in the early postoperative period in the control group. In the warming group, the reduced skin temperature at arrival at the ward approximated to the core temperature leading to significant reduction of the temperature gap and increasing the perfusion index to the preoperative level. Although less evident, both the temperature gap and peripheral perfusion significantly improved in the exercise group after 6 and 8 h after arrival at the ward, respectively.

CONCLUSIONS

Vasoconstriction in response to cessation after anesthesia and surgery serves to maintain core temperature, but impairs peripheral circulation. Active warming and intermittent mild exercise immediately after arrival at the ward reduces the temperature gap and improves peripheral circulation during the early postoperative period. While cost-effectiveness needs to be considered before clinical application of the intervention, the cost-free mild exercise may be a feasible option for improving postoperative patient care.

Effect of heated humidified ventilation on intraoperative core temperature and prognosis in normothermic thoraco-abdominal aortic aneurysm repair

Background

To evaluate whether the heated humidified ventilation can effectively maintain core temperature and improve prognosis in normothermic thoraco-abdominal aortic aneurysm repair surgery.

Methods

Patients who were scheduled for normothermic thoraco-abdominal aortic aneurysm repair surgery were randomized into the group using heated humidified ventilation combined with water blanket and the group using water blanket only. During the operation, the core temperature will be measured every 30 minutes. We analyzed intraoperative core-temperature, coagulation function and in-hospital mortality.

Results

HHV&WB group showed lesser decrease in core temperature than WB groups in the first two hours, while WB group had a higher body temperature at the third to fifth hour (2-hour: 35.45±0.47 vs. 35.24±0.59 °C, P=0.284; 5-hour: 35.38±0.70 vs. 35.51±0.88 °C, P=0.664). There was less blood loss, dosage of coagulation drugs and in-hospital mortality (13.33% vs. 20.00%, P=1) in the HHV&WB group.

Conclusions

Heated humidified ventilation can improve the prognosis of normothermic thoraco-abdominal aortic aneurysm repair surgery to some extent, but it can only maintain the core temperature during the first 2 hours.

Room Temperature Versus Warm Irrigation Fluid Used for Patients Undergoing Arthroscopic Shoulder Surgery: A Systematic Review and Meta Analysis

PURPOSE

The aim of this study was to analyze whether warm irrigation fluid could reduce postoperative adverse effects in patients undergoing arthroscopic shoulder surgery compared with room temperature irrigation fluid.

DESIGN

A systematic review and meta-analysis of clinical trials was performed.

METHODS

A computerized search of electronic databases was performed. The inclusion criteria were studies comparing the clinical effects of room temperature and warm irrigation fluid on patients undergoing arthroscopic shoulder surgery.

FINDINGS

Warm irrigation fluid reduced the degree of core body temperature drop and the incidence of hypothermia. A statistically lower incidence of shivering also occurred in the warm irrigation fluid group.

CONCLUSIONS

The use of warm irrigation fluid better maintains core body temperature and reduces incidence of shivering than room temperature irrigation fluid. Therefore, warm irrigation fluid is a better choice for arthroscopic shoulder surgery.

Efficacy of Forced-Air Warming to Prevent Perioperative Hypothermia in Morbidly-Obese Versus Non-obese Patients

BACKGROUND

Hypothermia is associated with an increased postoperative morbidity and mortality. Forced-air warming systems are the most effective methods for its prevention. When using a mattress, a reduction in the area of diffusion of warm air by crushing due to excess weight cannot be ruled out.

METHODS

We designed a prospective study to compare the efficacy of a forced-air warming mattress (Bair Hugger® 585) to prevent hypothermia (core temperature (CT°) < 36 °C) in morbidly obese (group MO, body mass index (BMI) ≥ 40 kg/m²) and non-obese patients (group NO, BMI < 30 kg/m²).

RESULTS

Twenty-six patients were included in group MO (84% bariatric surgery, 96% laparoscopic procedures) and 32 in group NO (37.5% cholecystectomy, 62.5% laparoscopic procedures). The incidence of hypothermia was not different between the two groups 1 h after induction (H1) and at extubation: 22 vs 19% (not significant (NS)) and 23 vs 19% (NS) for the group MO versus group NO. At H1, the mean CT° was not different: 36.3 ± 0.4 °C vs 36.4 ± 0.5 °C (NS), group MO versus group NO. No patient presented severe hypothermia (CT° < 34.9 °C). Dysfunction of the forced-air warming mattress was observed for eight patients (31%) in group MO but for none in group NO.

CONCLUSION

The forced-air warming mattress is effective in preventing hypothermia in MO patients. However, excess weight is associated with frequent dysfunction of the system, which does not make it a practical system in a context of MO.

New Concept Air Conditioning System for the Operating Room to Minimize Patient Cooling and Surgeon Heating: A Historical Control Cohort Study

BACKGROUND

Intraoperative hypothermia is a common adverse event. For avoiding the complication due to hypothermia, many warming devices and methods have been used in perioperative period. It has been reported that more patients undergoing laparoscopic surgery tend to have hypothermia than with open surgery. To avoid intraoperative hypothermia, many kinds of warming tools have been used. But, it was also reported that some warming methods increased perceptions of distraction and physical demand.

METHODS

To achieve both patients' normothermia and surgeons' comfort, new air conditioning (AC) system was designed with considering the characteristics of laparoscopic surgery. The temperature of the airflows to the patient and to the surgeons can be adjusted independently in this new system. The new system has two parts. One controls the temperature of the central area over the operation table. The air from this part falls on the patients. The other part is the lateral area beside the operating table; the air from this part falls on the surgeons. The subjects of this study were 160 gastric cancer patients and 316 colorectal cancer patients undergoing laparoscopic surgery. The temperature of the central flow was set 23.5 °C, and the temperature of the lateral flow was set 22 °C just after the anesthesia. The number of timepoints the patient spent in hypothermic state, defined as a temperature cooler by 0.5 °C or more than that at the starting point of surgery, was determined in each patient.

RESULTS

In the results, the rate of hypothermic state in old operation rooms was 23.8% and that in new operation rooms was 2.7% in male gastric cancer patients (p < 0.01). And those were 37.1% in old operation rooms and 0.9% in new operation rooms in female gastric cancer patients (p < 0.01). The rate of hypothermic state in old operation rooms was 30.0% and that in new operation rooms was 9.5% in male colorectal cancer patients (p < 0.01). And those were 41.6% in old operation rooms and 8.9% in new operation rooms in female colorectal cancer patients (p < 0.01). The similar results were showed in the study, which subjects were limited the patients undergoing surgery in 2015 and 2016; which were the last year the old operation rooms were used and the first year the new operation rooms were used.

CONCLUSIONS

Thus, the usefulness of the new air conditioning system for achieving both patients' normothermia and comfort of surgeons could be verified in this study.

Selective brain hypothermia: feasibility and safety study of a novel method in five patients

BACKGROUND/OBJECTIVE

Reduction of brain temperature remains the most common method of neuroprotection against ischemic injury employed during cardiac surgery. However, cooling delivered via the cardiopulmonary bypass circuit is brief and cooling the body core along with the brain has been associated with a variety of unwanted effects. This study investigated the feasibility and safety of a novel selective brain cooling approach to induce rapid, brain-targeted hypothermia independent of the cardiopulmonary bypass circuit.

METHODS

This first-in-human feasibility study enrolled five adults undergoing aortic valve replacement with cardiopulmonary bypass support. During surgery, the NeuroSave system circulated chilled saline within the pharynx and upper esophagus. Brain and body core temperature were continuously monitored. Adverse effects, cardiopulmonary function, and device function were noted.

RESULTS

Patient 1 received cooling fluid for an insignificant period, and Patients 2-5 successfully underwent the cooling procedure using the NeuroSave system for 56-89 minutes. Cooling fluid was 12°C for Patients 1-3, 6°C for Patient 4, and 2°C for Patient 5. There were no NeuroSave-related adverse events and no alterations in cardiopulmonary function during NeuroSave use. Brain temperature decreased by 3°C within 15 minutes and remained at least 3.5°C colder than the body core. During a brief episode of hypotension in one patient, the brain cooled an additional 4°C in 2 minutes, briefly reaching 27.4°C.

CONCLUSION

The NeuroSave system can induce rapid brain-targeted hypothermia and simultaneously maintain a favorable body-brain temperature gradient, even during hypotension. Further studies are required to evaluate the function of the system during longer periods of use.

Incidence and Risk Factors for Postoperative Hypothermia After Orthopaedic Surgery

INTRODUCTION

Postoperative hypothermia is a common complication of orthopaedic surgery associated with increased morbidity. We identified the incidence and risk factors for postoperative hypothermia across orthopaedic surgical procedures.

METHODS

A total of 3,822 procedures were reviewed. Hypothermia was defined as temperature <36.0°C. Incidences were calculated and associated risk factors were evaluated by mixed-effects regression analyses.

RESULTS

Hypothermia was observed in 72.5% of patients intraoperatively and 8.3% postoperatively. Risk factors for postoperative hypothermia included intraoperative hypothermia (odds ratio [OR], 2.72), lower preoperative temperature (OR, 1.46), female sex (OR, 1.42), lower body mass index (OR, 1.06 per kg/m), older age (OR, 1.02 per year), adult reconstruction by specialty (OR, 4.06), and hip and pelvis procedures by anatomic region (OR, 8.76).

DISCUSSION

Intraoperative and postoperative hypothermia are common in patients who have undergone orthopaedic surgery. The high-risk groups identified in this study warrant increased attention and should be targets for interventions to prevent hypothermia and limit morbidity.

LEVEL OF EVIDENCE

Level IV, prognostic study.

Thermoelectric Heat Patch for Clinical and Self-Management: Melanoma Excision Wound Care

Thermotherapy is considered to have potential beneficial effects when applied to wounds. Of particular relevance to this research are wounds that have dropped in temperature due to regional anaesthesia. This study is aimed at developing a normothermic system comprising of a heat patch controlled by external hardware. The study is divided into three parts: (i) the analyses of the skin temperature that form the foundation of the system; (ii) the development of an efficient wearable heat patch incorporating thermoelectric elements to electrical and thermal conductive textiles; and (iii) the hardware development to control the current flow to the thermoelectric elements thus managing the temperature of the heat patch and conserving current. It was observed that a distance of 3 cm between the thermoelectric elements provides ideal heat distribution relative to the surface area. The system allowed for an 80% reduction in current, while maintaining the temperature of the heat patch at the required thermophysiological skin temperature. Future studies will include development of a temperature sensor identifying the real-time temperature of the wound; and circuitry for switching the polarity of the thermoelectric elements. The cooling capabilities of the thermoelectric elements can be applied to wounds that have increased in temperature.

Benefits of Passive Warming on Surgical Patients Undergoing Regional Anesthetic Procedures

PURPOSE

The purpose of this quality improvement project was to determine if application of preoperative passive warming methods would maintain body temperature in patients receiving regional anesthetic procedures (RAPs).

DESIGN

A nonrandomized quasi-experimental design was used.

METHODS

A passive warming trial using a convenience sample of 53 RAP patients warmed with passive measures was compared with data collected from 67 retrospective chart reviews of RAP patients warmed per standard unit policy-typically active forced warm air. Passive measures included a thermal reflective surgical cap and an activated chemical warmer.

FINDINGS

Passive warming methods maintained temperatures throughout the perioperative process. No significant variations in mean temperatures were noted. As age increased, the difference in temperature from admit to transfer to operating room also increased (P = .0182).

CONCLUSIONS

Passive warming is a suitable cost-effective alternative when forced-air warming is not feasible. Additional inquiry into the use of passive warming is warranted.

Back to Basics: Unplanned Patient Hypothermia: 1.3 www.aornjournal.org/content/cme

Unplanned perioperative hypothermia is a common occurrence and can negatively affect a patient's postoperative course. Perioperative nurses are responsible for identifying patients at risk for hypothermia and working with the entire surgical team to prevent this complication from occurring. Multiple interventions can be implemented to address hypothermia, including active or passive warming and warm IV and irrigation fluids. This Back to Basics article addresses patient assessment concerns, identifies a variety of evidence-based interventions that can prevent or mitigate perioperative patient temperature changes, and provides basic steps for perioperative RNs to follow to help prevent perioperative hypothermia in their patients.

Examination of intra-operative core temperature in joint arthroplasty: a single-institution prospective observational study

PURPOSE

Peri-operative hypothermia is associated with increased blood loss, delayed wound healing, and surgical site infections. However, it is not known when or how rapidly hypothermia develops during arthroplasty. This study observed patients undergoing lower extremity arthroplasty to identify the times of greatest heat loss or gain.

METHODS

This single-institution prospective observational study enrolled 120 patients undergoing elective knee or hip arthroplasty for peri-operative temporal temperature measurements at ten prespecified intervals. Incidence of hypothermia was the primary outcome. A secondary aim was to identify patient and operative factors associated with hypothermia. Descriptive statistics were calculated for fixed time variables. Associations for the occurrence of hypothermia over time were conducted using generalized linear mixed models with a logit link and a random subject effect to account for repeated measures on the same individual over time.

RESULTS

Most patients, 72.6%, experienced hypothermia with 20.6% hypothermic for over one hour and 47.1% hypothermic after surgery. In the multivariable model, increased odds of hypothermia were associated with female gender (P = 0.017), knee arthroplasty (P < 0.001), neuraxial anaesthesia (P < 0.001), lower patient pre-operative temperature (P < 0.001), and lower operating room temperature (P = 0.042). A 0.5 °C decrease in patient pre-operative temperature or operating room temperature was associated with a 97 and 11% increase in the odds of hypothermia, respectively, controlling for other factors.

CONCLUSION

In our series, peri-operative hypothermia remains common for patients undergoing arthroplasty. Female gender, low pre-operative temperature, knee arthroplasty, and neuraxial anesthesia were associated with hypothermia. Further preventative strategies and studies on interventions to reduce hypothermia are needed.

The Effect of Operating Room Temperature on the Performance of Clinical and Cognitive Tasks

Introduction:

Operating room (OR) temperature may impact the performance of health care providers. This study assesses whether hot or cold room temperature diminishes the performance of OR personnel measured by psychomotor vigilance testing (PVT) and self-report scales.

Methods:

This prospective observational study enrolled surgical/anesthesia trainees, student registered nurse anesthetists, and certified registered nurse anesthetists. Each provider participated in a test of psychomotor function and a questionnaire using a self-report scale of personal comfort and well-being. The PVT and questionnaires were completed after 30 minutes of exposure to 3 different conditions (temperature of 21°C, 23°C, and 26°C).

Results:

The cohort of 22 personnel included 9 certified registered nurse anesthetists, 7 anesthesia/surgical trainees, and 6 student registered nurse anesthetists. Mean reaction time on the PVT was comparable among baseline (280 ± 47 ms), hot (286 ± 55 ms; P = 0.171), and cold (303 ± 114 ms; P = 0.378) conditions. On the self-report score (range, 1–21), there was no difference in the self-rated subjective performance between baseline and cold conditions. However, the self-rated subjective performance scale was lower (12 ± 6, P = 0.003) during hot conditions.

Discussion:

No difference was noted in reaction time depending on the temperature; however, excessive heat in the OR environment was associated with worse self-rated subjective performance among health care providers. Particularly, self-rated subjective physical demand and frustration were greater under hot condition.

Propionibacterium acnes Suture Contamination in Arthroscopic Rotator Cuff Repair: A Prospective Randomized Study

PURPOSE

To examine the contamination rate of the anchor-suture and to determine the efficacy of 2 different surgical skin preparation solutions with or without a plastic adhesive drape from suture contamination in arthroscopic rotator cuff repair.

METHODS

A prospective randomized study was undertaken to evaluate 126 consecutive patients undergoing arthroscopic rotator cuff repair. Each shoulder was prepared with one of 2 randomly selected solutions according to an assigned envelope that indicated the procedure to be used: chlorhexidine-alcohol (1% chlorhexidine gluconate and 70% isopropyl alcohol) or povidone-iodine. Then, each group was further divided according to the usage of a plastic drape. The first cut-tails of the anchor-suture after cuff fixation were submitted to aerobic and anaerobic cultures.

RESULTS

The overall rate of Propionibacterium acnes-positive cultures was 47% (14 of 31 cases) in the povidone-iodine group, 33% (11 of 33 cases) in the povidone-iodine with a drape group, 33% (10 of 30 cases) in the chlorhexidine-alcohol group, and 9.3% (3 of 32 cases) in the chlorhexidine-alcohol with a drape group. The positive culture rate in the chlorhexidine-alcohol with a drape group was lower than that in the povidone-iodine group (relative risk, 0.2; 95% confidence interval: 0.064-0.63; number needed to treat, 2.7; P < .0001). Coagulase-negative staphylococci were isolated in the povidone-iodine with a drape (1 case) and chlorhexidine-alcohol with a drape group (2 cases). No other bacteria were isolated, and no infections occurred in any of the patients treated in this study during the minimum 12-month follow-up period.

CONCLUSIONS

Chlorhexidine-alcohol solution with an adhesive plastic drape was more effective than chlorhexidine-alcohol without a plastic drape and povidone-iodine with/without a plastic drape in eliminating P acnes suture contamination. However, the usage of a plastic drape slightly increased the risk of coagulase-negative Staphylococcus proliferation.

LEVEL OF EVIDENCE

Level I, therapeutic, prospective, randomized trial.

The incidence of mild hypothermia after total knee or hip arthroplasty: A study of 2600 patients

Hypothermia is associated with a higher risk of perioperative complications and occurs frequently after total joint arthroplasty (TJA). The incidence of hypothermia following total joint arthroplasty was assessed with its risk factors and its correlation with PJI. Correlation of hypothermia with age, gender, BMI, type of arthroplasty surgery, type of anesthesia, operation time, blood loss, date of surgery and PJI was evaluated in 2600 patients. Female gender and spinal anesthesia increased the risk for hypothermia whereas an increased BMI and surgery duration correlated decreased the risk of hypothermia. The incidence of hypothermia decreased over time without a correlation with PJI.

Investigation of the HotDog patient warming system: detection of thermal gradients

OBJECTIVE

To assess the performance of an active patient-warming device.

MATERIALS AND METHODS

Temperatures of an active patient-warming device (HotDog system) were measured at various time points using an infrared thermometer. The study was conducted in two phases: Phase 1 compared temperatures among four different areas of the warming blanket. Phase 2 compared conditions simulating different scenarios using a weighted patient simulator.

RESULTS

Phase 1: Three out of four positions on the warming blanket had significantly different temperature measurements. Phase 2: Temperature output by the warming blanket was reduced: (1) in the absence of the patient simulator placed across the blanket (-1·9°C, P=0·013); (2) if the patient simulator was placed away from the blanket sensor (-2·0°C, P=0·009); and (3) if there was fluid between the patient simulator and warming blanket (-2·2°C, P=0·004). In a majority of measurements (95%), the set temperature of 43°C on the control unit was not reached (range, 29·8 to 42·9°C) and 2·3% of measurements were higher (range, 43·1 to 45·8°C) than the control unit set temperature of 43°C.

CLINICAL SIGNIFICANCE

Measured temperatures on the active warming blanket did not reflect control unit settings. This could result in the potential for hyperthermic injury, ineffectual heating and uneven heat distribution.

Comparison of Prophylactic Intravenous Magnesium Sulfate with Tramadol for Postspinal Shivering in Elective Cesarean Section: A Placebo Controlled Randomized Double-blind Pilot Study

Background and Aims:

Cesarean sections are performed mostly under spinal anesthesia. Shivering is one of the distressing complications. The aim of the study was to compare the efficacy of intravenous (i.v) magnesium sulfate and tramadol with placebo (normal saline) on postspinal shivering in elective cesarean section when used as prophylaxis.

Methods:

One hundred and thirty-five pregnant women between 18 and 35 years age, belonging to the American Society of Anesthesiologists’ physical Status II, undergoing elective cesarean section under spinal anesthesia were enrolled into the study. Patients belonging to Group C (control group, n = 45) received isotonic saline 100 mL i.v, Group T (tramadol group, n = 45) received tramadol 0.5 mg/kg in 100 mL isotonic saline i.v, whereas those in Group M (magnesium sulfate group, n = 45) received magnesium sulfate 30 mg/kg in 100 mL isotonic saline i.v after administering spinal anesthesia. Incidence and grades of shivering were noted. Data were analyzed using one-way ANOVA test and Chi-square test.

Results:

The incidence of shivering in Group C, Group T, and Group M were 67.5%, 43.9%, and 39%, respectively. The incidence of shivering in Group M and Group T was significantly low when compared to Group C (P = 0.008; P = 0.026), whereas there was no statistically significant difference between Groups T and M (P = 0.654).

Conclusion:

Magnesium sulfate and tramadol significantly reduce the incidence of shivering compared to placebo when used as prophylaxis in pregnant women undergoing cesarean section under spinal anesthesia. Magnesium sulfate reduces the severity of the shivering.

Effect of operating room care combined with home care for the postoperative rehabilitation and prognosis of gastric cancer patients with low PTEN gene expression

The aim of the present study was to analyze the effect of operating room (OR) care combined with home care on postoperative rehabilitation and prognosis of gastric cancer patients with low PTEN gene expression. Ninety-six gastric cancer patients with low PTEN gene expression, who underwent surgical treatment in our hospital were recruited. PTEN expression was measured by semi-quantitative polymerase chain reaction. Participants were randomized into the observation and control groups, with 48 cases each. Participants in the two groups received the same preoperative examination, gastric cancer surgery, postoperative drug therapy, and general care, while observation group participants were provided more comprehensive OR care combined with home care. After 1 year of home care, the self-rating anxiety scale (SAS) and Hamilton anxiety scale (HAMA) scores, rehabilitation status, overall quality of life, and Family Adaptability and Cohesion Scale were applied to compare postoperative rehabilitation and prognosis status in both groups. Data were statistically analyzed. Patients were followed up for 3 years, and survival time was analyzed. The operative time and bleeding volume between the two groups were not significantly different (p>0.05). The time of extubation and postoperative recovery time in the observation group were shorter than in the control group (p<0.01). The postoperative SAS and HAMA scores in both groups were significantly decreased compared with those preoperatively (p<0.01). Additionally, these scores were significantly lower in the observation than in the control group (p<0.01). The rehabilitation status of body function in the observation group was better than in the control group (p<0.01). Regarding the overall quality of life score and family adaptability and cohesion score, the observation group was better than the control group (p<0.01). In conclusion, OR care combined with home care was effective for the care of gastric cancer patients with low PTEN expression. Improving patient mood and mental state played a positive role in postoperative rehabilitation and prognosis.

Forced-air pre-warming prevents peri-anaesthetic hypothermia and shortens recovery in adult rats

General anaesthesia disrupts thermoregulation in mammals, which can cause hypothermia. Decreases in core body temperature of 1℃ cause significant postoperative complications in humans, and peri-anaesthetic hypothermia in mice increases data variability, which can potentially increase animal use. In rats, the impact of different temperature management strategies on the incidence and severity of hypothermia, and the accuracy of different temperature measurement methods, is unknown. Eighteen adult male and female SD rats were block-randomized to one of three treatment groups: no-warming (NW), limited-warming (LW, heat pad during anaesthesia), and pre-warming (PW, warm air exposure before anaesthesia, followed by heat pad). Anaesthesia (isoflurane) duration was for 40 min. Core body temperature (intra-abdominal telemetric temperature capsule) was recorded during anaesthesia and recovery. During anaesthesia, rectal, skin, and tail temperatures were also recorded. In the PW group, core temperature was maintained during anaesthesia and recovery. By contrast, the NW group was hypothermic (11% temperature decrease) during anaesthesia. The LW group showed a decrease in temperature during recovery. Recovery to sternal recumbency was significantly faster in the PW (125 [70-186] s, P = 0.0003) and the LW (188 [169-420] s, P = 0.04) groups than in the NW group (525 [229-652] s). Rectal temperature underestimated core temperature (bias -0.90℃, 95% limits of agreement -0.1 to 1.9℃). Skin and tail temperatures showed wide 95% limits of agreement, spanning 6 to 15℃, respectively. The novel strategy of PW was effective at maintaining core temperature during and after anaesthesia. Rectal temperature provided an acceptable proxy for core body temperature.

The effect of humidified heated breathing circuit on core body temperature in perioperative hypothermia during thyroid surgery

Purpose: During general anesthesia, human body easily reaches a hypothermic state, which is mainly caused by heat redistribution. Most studies suggested that humidified heated breathing circuits (HHBC) have little influence on maintenance of the core temperature during early phase of anesthesia. This study was aimed at examining heat preservation effect with HHBC in case of undergoing surgery with less exposure of surgical fields and short surgical duration. Methods: Patients aged 19 to 70 yr - old, ASA-PS I or II who were scheduled for elective thyroidectomy were assigned and divided to the group using HHBC (G1) and the group using conventional circuit (G2) by random allocation. During operation, core, skin, and room temperatures were measured every 5minutes by specific thermometer. Results: G1 was decreased by a lesser extent than G2 in core temperature, apparently higher at 30 and 60 minutes after induction. Skin and room temperatures showed no differences between the two groups (p>0.05). Consequently, we confirmed HHBC efficiently prevented a decrease in core temperature during early period in small operation which has difficulty in preparing warming devices or environments were not usually considered. Conclusions: This study showed that HHBC influences heat redistribution in early period of operation and can lessen the magnitude of the decrease in core body temperature. Therefore, it can be applied efficiently for other active warming devices in mild hypothermia.

Guideline Implementation: Preventing Hypothermia

The updated AORN "Guideline for prevention of unplanned patient hypothermia" provides guidance for identifying factors associated with intraoperative hypothermia, preventing hypothermia, educating perioperative personnel on this topic, and developing relevant policies and procedures. This article focuses on key points of the guideline, which addresses performing a preoperative assessment for factors that may contribute to hypothermia, measuring and monitoring the patient's temperature in all phases of perioperative care, and implementing interventions to prevent hypothermia. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures.