The effect of electrically heated humidifier on the body temperature and blood loss in spinal surgery under general anesthesia

Barriers and facilitators to evidence-based perioperative hypothermia management for orthopaedic patients: A systematic review

AIM

To assess barriers and facilitators to the implementation of guidelines for the prevention of inadvertent perioperative hypothermia in orthopaedic patients.

DESIGN

Systematic review.

DATA SOURCES

Nine databases: PubMed, Embase, CINAHL, Cochrane CENTRAL, PsycINFO, ProQuest Dissertations and Theses, Scopus, Web of Science and Trip Clinical Evidence Database.

METHODS

Primary studies published in English between January 2008 to July 2022 were screened. Study selection, quality assessment, and data extraction were completed independently by researchers. Data were extracted using the Consolidated Framework for Implementation Research and mapped to the Expert Recommendations for Implementing Change strategies.

RESULTS

Eighty-seven studies were included in the review. The most frequently reported barriers and facilitators related to evidence strength, relative advantage, and cost of implementing perioperative hypothermia prevention guidelines. The top four ERIC strategies were: Identify and prepare champions; Conduct educational meetings; Assess for readiness and identify barriers and facilitators; and Inform local opinion leaders.

CONCLUSION

This review provides synthesized evidence regarding barriers and facilitators to perioperative hypothermia guidelines for patients undergoing orthopaedic surgery.

IMPLICATIONS FOR THE PROFESSION AND PATIENT CARE

Our work provides theory guided strategies to promote implementation of perioperative hypothermia prevention to assist nurses caring for patients undergoing orthopaedic surgery.

IMPACT

Findings provide professionals caring for patients undergoing orthopaedic surgery with theory-informed strategies to improve perioperative hypothermia prevention. Reducing perioperative hypothermia will improve outcomes for patients undergoing orthopaedic surgery.

REPORTING METHOD

The review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020.

NO PATIENT OR PUBLIC CONSULTATION

Due to the study design, no patient or public consultation took place.

Concordance of esophageal and tracheal temperatures in patients using breathing circuit with heated wire humidifier: A prospective observational study

RESULTS

After excluding 4 patients with an anesthesia duration of < 2 hours, data from 34 patients (1163 sets of tracheal and esophageal temperatures) were analyzed. Concordance correlation coefficient was 0.78. The overall mean bias (95% limits of agreement) between the tracheal and esophageal temperatures was -0.16°C (-0.65°C to 0.34°C). The percentage of temperature differences within ± 0.25°C was 73.5% ± 32.3, with a median of 89.4% [0,100]. The linear mixed-effects model revealed that the estimated intercept was 0.17°C with a 95% confidence interval (CI) of 0.13°C to 0.22°C. The duration of anesthesia and the number of temperature measurements were associated with higher concordance between the tracheal and esophageal temperatures in univariate analysis.

The Impact of Rocuronium and Sugammadex on Length of Stay in Patients Undergoing Open Spine Surgery: A Propensity Score-Matched Analysis

Enhanced Recovery After Surgery (ERAS), an all-encompassing perioperative care approach, has been demonstrated to enhance surgical results, mitigate postoperative issues, and decrease the length of hospital stay (LOS) in diverse surgical specialties. In this retrospective study, our objective was to examine the influence of muscle relaxant selection on LOS and perioperative results in adult patients undergoing open spine surgery. Specifically, we compared 201 patients who received cisatracurium and neostigmine with 201 patients who received rocuronium and sugammadex, after 1:1 propensity score matching. The utilization of the rocuronium and sugammadex combination in anesthesia for open spinal surgery did not lead to a reduction in the LOS but was associated with a decreased incidence of postoperative chest radiographic abnormalities, including infiltration, consolidation, atelectasis, or pneumonia (p = 0.027). In our secondary analysis, multivariate analysis revealed multiple determinants influencing the prolonged LOS (>7 days) during open spine surgery. Bispectral index-guided anesthesia emerged as a protective factor, while variables such as excessive intraoperative blood loss and fluid administration as well as postoperative chest radiographic abnormalities independently contributed to prolonged LOS.

Effect of active airway warming with a heated-humidified breathing circuit on core body temperature in patients under general anesthesia: a systematic review and meta-analysis with trial sequential analysis

BACKGROUND

The application of a heated-humidified breathing circuit (HHBC) may reduce respiratory heat loss during mechanical ventilation, but its effect in preventing intraoperative hypothermia is controversial. This study aimed to investigate the effectiveness of HHBC in maintaining the core temperature of patients receiving mechanical ventilation under general anesthesia.

METHODS

We searched MEDLINE, Embase, Cochrane library (CENTRAL), and Google Scholar to identify all randomized controlled trials (RCTs) up to February 2022 that compared the intraoperative core temperature in patients with heated humidifier (HH) and other circuit devices. The primary outcome was the intraoperative core temperature at the end of surgery. The weighted mean differences (WMDs) between the groups and their 95% CIs were calculated for each outcome. We performed a trial sequential analysis of the primary outcomes to assess whether our results were conclusive.

RESULTS

Eighteen RCTs with 993 patients were included in the analysis. A significantly higher core temperature was observed at the end of surgery in patients with HH than those with no device (WMD = 0.734, 95% CI [0.443, 1.025]) or heat and moisture exchanger (WMD = 0.368, 95% CI [0.118, 0.618]), but with substantial heterogeneity.

CONCLUSIONS

Although HHBC did not absolutely prevent hypothermia, this meta-analysis suggests that it can be used as an effective supplemental device to maintain the intraoperative core temperature under general anesthesia. However, considering the substantial heterogeneity and limitations of this study, further well-designed studies are needed to clarify the effectiveness of HHBC.

Perioperative Care of Patients Undergoing Major Complex Spinal Instrumentation Surgery: Clinical Practice Guidelines From the Society for Neuroscience in Anesthesiology and Critical Care

Evidence-based standardization of the perioperative management of patients undergoing complex spine surgery can improve outcomes such as enhanced patient satisfaction, reduced intensive care and hospital length of stay, and reduced costs. The Society for Neuroscience in Anesthesiology and Critical Care (SNACC) tasked an expert group to review existing evidence and generate recommendations for the perioperative management of patients undergoing complex spine surgery, defined as surgery on 2 or more thoracic and/or lumbar spine levels. Institutional clinical management protocols can be constructed based on the elements included in these clinical practice guidelines, and the evidence presented.

Heated Humidified Breathing Circuit Rewarming in Hypothermic Patients Post-Cardiopulmonary Bypass-Pilot Study

OBJECTIVES

Hypothermia on intensive care unit (ICU) admission after cardiac surgery and cardiopulmonary bypass is common. It contributes to postoperative complications including shivering, coagulopathy, increased blood loss and transfusion requirements, morbid cardiac events, metabolic acidosis, increased wound infections, and prolonged hospital length of stay. The current standard of care for rewarming ICU patients is forced air warming blankets. However, high-quality evidence on additional benefit rendered by other warming methods, such as heated humidified breathing circuits (HHBC), is lacking. Therefore, the authors conducted a pilot study to examine whether the addition of HHBC to standard forced air warming blankets in hypothermic patients (≤35°C) admitted to the ICU after cardiac surgery using cardiopulmonary bypass reduced time to normothermia.

DESIGN

Prospective study conducted at a single large academic medical center.

PARTICIPANTS

The study group was composed of 14 patients who were enrolled prospectively between April 1 and June 14, 2019. The study group was compared with a 2:1 matched retrospective control group. The matched group consisted of 28 patients from a 12-month period from July 1, 2018 June 30, 2019.

INTERVENTIONS

Study patients received warming via forced air warming blankets and HHBC and were compared with patients in a control group who received only warming blankets. Time to normothermia, time to extubation, time to normal pH, blood loss, blood transfusions, and coagulation profile laboratory values were compared between the study and control groups.

MEASUREMENTS AND MAIN RESULTS

The present study found no statistical difference in time to normothermia, for which the standard-of-care retrospective group achieved normothermia after a median (Q1-Q3) 4.8 (4.0-6.0) hours compared with 4.4 (3.5-5.5) hours in the prospective group receiving HHBC. All secondary outcomes, including time to extubation, time to normal pH, ICU blood product transfusion, chest tube output, and coagulation profile, were similar.

CONCLUSIONS

The present pilot study detected a similar time to normothermia, extubation, and normal pH when HHBC were added to standard forced air warming blankets in hypothermic patients (≤35°C) admitted to the ICU after cardiac surgery using cardiopulmonary bypass. A future larger prospective study designed to detect smaller, but clinically meaningful, reductions in the time to key clinical events for patients treated with HHBC is feasible and warranted.

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.

The Impact of Intraoperative Hypothermia on Blood Loss and Allogenic Blood Transfusion in Total Knee and Hip Arthroplasty: A Retrospective Study

Background

Total joint arthroplasty (TJA) usually leads to substantial blood loss, which may cause allogenic blood transfusion. Hypothermia occurring during operation has been reported to increase blood loss and transfusion rates in nonorthopedic cohorts. However, the relationship between intraoperative hypothermia and blood loss remains controversial in patients undergoing orthopedic surgeries. The aims of this study were to investigate the incidence of hypothermia and identify the impact of intraoperative body temperature and hypothermia on blood loss and transfusion rates in total knee and hip arthroplasty (TKA and THA, respectively).

Methods

This retrospective study enrolled 616 consecutive patients, who underwent primary unilateral TKA or THA at our institution during the period from April 2012 to July 2014. The occurrence of a temperature below 36°C during the operation was documented to identify the incidence of hypothermia. Univariate analysis was performed to find the risk factors for hypothermia. Multiple regression analysis and multivariate logistic regression analysis were employed to explore the association of intraoperative temperature and hypothermia with intraoperative blood loss and perioperative blood transfusion.

Results

The incidence of intraoperative hypothermia was 13.5%, 14.0%, and 13.1% in TJA, TKA, and THA, respectively. Intraoperative temperature (P = 0.045, P = 0.006) and hypothermia (P = 0.042, P < 0.001) were associated with intraoperative blood loss and perioperative transfusion in TKA. Intraoperative temperature (P = 0.002) was negatively related to the amount of blood loss, and hypothermia (P = 0.031) was the independent risk factor for transfusion in THA.

Conclusion

Intraoperative hypothermia is associated with increased blood loss and transfusion rates in TJA. Efforts should be made to maintain normothermia during operation in these patients.

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.

Effects of positive end-expiratory pressure on intraoperative core temperature in patients undergoing posterior spine surgery: prospective randomised trial

Objective Positive end-expiratory pressure (PEEP) causes carotid baroreceptor unloading, which leads to thermoregulatory peripheral vasoconstriction. However, the effects of PEEP on intraoperative thermoregulation in the prone position remain unknown. Methods Thirty-seven patients undergoing spine surgery in the prone position were assigned at random to receive either 10 cmH₂O PEEP (Group P) or no PEEP (Group Z). The primary endpoint was core temperature 180 minutes after intubation. Secondary endpoints were delta core temperature (difference in core temperature between 180 minutes and immediately after tracheal intubation), incidence of intraoperative hypothermia (core temperature of <36°C), and peripheral vasoconstriction-related data. Results The median [interquartile range] core temperature 180 minutes after intubation was 36.1°C [35.9°C-36.2°C] and 36.0°C [35.9°C-36.4°C] in Groups Z and P, respectively. The delta core temperature and incidences of intraoperative hypothermia and peripheral vasoconstriction were not significantly different between the two groups. The peripheral vasoconstriction threshold (36.2°C±0.5°C vs. 36.7°C±0.6°C) was lower and the onset of peripheral vasoconstriction (66 [60-129] vs. 38 [28-70] minutes) was slower in Group Z than in Group P. Conclusions Intraoperative PEEP did not reduce the core temperature decrease in the prone position, although it resulted in an earlier onset and higher threshold of peripheral vasoconstriction.

Heated wire humidification circuit attenuates the decrease of core temperature during general anesthesia in patients undergoing arthroscopic hip surgery

Background

Intraoperative hypothermia is common in patients undergoing general anesthesia during arthroscopic hip surgery. In the present study, we assessed the effect of heating and humidifying the airway with a heated wire humidification circuit (HHC) to attenuate the decrease of core temperature and prevent hypothermia in patients undergoing arthroscopic hip surgery under general anesthesia.

Methods

Fifty-six patients scheduled for arthroscopic hip surgery were randomly assigned to either a control group using a breathing circuit connected with a heat and moisture exchanger (HME) (n = 28) or an HHC group using a heated wire humidification circuit (n = 28). The decrease in core temperature was measured from anesthetic induction and every 15 minutes thereafter using an esophageal stethoscope.

Results

Decrease in core temperature from anesthetic induction to 120 minutes after induction was lower in the HHC group (–0.60 ± 0.27℃) compared to the control group (–0.86 ± 0.29℃) (P = 0.001). However, there was no statistically significant difference in the incidence of intraoperative hypothermia or the incidence of shivering in the postanesthetic care unit.

Conclusions

The use of HHC may be considered as a method to attenuate intraoperative decrease in core temperature during arthroscopic hip surgery performed under general anesthesia and exceeding 2 hours in duration.

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.

Relationship Between Hypothermia and Blood Loss in Adult Patients Undergoing Open Lumbar Spine Surgery

Context: Intraoperative blood loss during open lumbar spine surgery is associated with adverse events and is a contributor to higher medical costs. Intraoperative hypothermia has been shown to increase blood loss and postoperative allogeneic blood transfusion rates in other realms of orthopedic surgery, but it has not been studied extensively in patients undergoing spine surgery. Objective: To determine whether a clinically relevant association exists between intraoperative core body temperature and blood loss or transfusion rates in adult patients undergoing open lumbar spine surgery. Methods: In this retrospective medical record review, the surgical records of 174 adult patients who underwent open, nonmicroscopically assisted lumbar spine surgery performed by a single surgeon at a single institution were evaluated. Maximum, minimum, and average temperature, hypothermic temperature, and temperature range parameters were compared with intraoperative, total, and net blood loss and blood transfusion parameters. Additional patient demographic and perioperative characteristics were compared with blood loss and transfusion parameters to determine potential confounders. Analysis of variance, Spearman rank correlation, and generalized multiple linear regression analysis were performed to test for an association between temperature and blood loss or allogeneic transfusion rates. Statistical significance was set at P≤.05. Results: After implementation of exclusion criteria, 160 patient records and 168 surgical procedures were included in the analysis. For patients whose temperature decreased to a hypothermic level at some point during the procedure, hypothermic maximum temperature was protective against blood loss on bivariate analysis (P≤.02), but this finding lost significance after multivariate regression analysis (P>.09). Temperature range was associated with increased blood loss on bivariate analyses (P<.001) but also lost significance after adjusting for covariates in regression analysis (P≥.65). Surgery type (P≤.001) and operative time (P≤.001) were the most robust predictors of increased blood loss (P=.005) and were significantly associated with temperature (P<.001). Conclusion: No effect was found on perioperative blood loss from any temperature parameter or hypothermia in adult patients who underwent lumbar spine surgery once covariates were controlled for with multivariate analysis. One possible interpretation of these results is that the effect of temperature on blood loss can be explained by its strong relationship to the confounders of operative time and surgery type. J Am Osteopath Assoc. 2014;114(11):828-838 doi: 10.7556/jaoa.2014.169

Effect of heated humidified ventilation on bronchial mucus transport velocity in general anaesthesia: A randomized trial

Objective

To evaluate the effects of heated humidified ventilation on mucociliary function during general anaesthesia.

Methods

Male patients (ASA physical status 1 or 2), scheduled for elective radical retropubic prostatectomy, were allocated to receive sevoflurane general anaesthesia with conventional or heated humidified ventilation. Bronchial mucus transport velocity was assessed via fibreoptic bronchoscope and methylene blue dye at 3h after induction of anaesthesia.

Results

Median (SE) bronchial mucus transport velocity was significantly higher in the heated humidified group ( n = 26) than the conventional ventilation group ( n = 24) (1.7 [0.3] mm/min vs 0.9 [0.1] mm/min).

Conclusion

Heated humidified ventilation effectively maintains mucociliary clearance of patients during sevoflurane general anaesthesia.

The effect of warmed inspired gases on body temperature during arthroscopic shoulder surgery under general anesthesia

Background

Perioperative hypothermia can develop easily during shoulder arthroscopy, because cold irrigation can directly influence core body temperature. The authors investigated whether active warming and humidification of inspired gases reduces falls in core body temperature and allows redistribution of body heat in patients undergoing arthroscopic shoulder surgery under general anesthesia.

Methods

Patients scheduled for arthroscopic shoulder surgery were randomly assigned to receive either room temperature inspired gases using a conventional respiratory circuit (the control group, n = 20) or inspired gases humidified and heated using a humidified and electrically heated circuit (HHC) (the heated group, n = 20).

Results

Core temperatures were significantly lower in both groups from 30 min after anesthesia induction, but were significantly higher in the heated group than in the control group from 75 to 120 min after anesthesia induction.

Conclusions

In this study the use of a humidified and electrically heated circuit did not prevent core temperature falling during arthroscopic shoulder surgery, but it was found to decrease reductions in core temperature from 75 min after anesthesia induction.

The effect of heated breathing circuit on body temperature and humidity of anesthetic gas in major burns

BACKGROUND

Cold and dry gas mixtures during general anesthesia cause the impairment of cilliary function and hypothermia. Hypothermia and pulmonary complications are critical for the patients with major burn. We examined the effect of heated breathing circuit (HBC) about temperature and humidity with major burned patients.

METHODS

Sixty patients with major burn over total body surface area 25% scheduled for escharectomy and skin graft were enrolled. We randomly assigned patients to receiving HBC (HBC group) or conventional breathing circuit (control group) during general anesthesia. The esophageal temperature of the patients and the temperature and the absolute humidity of the circuit were recorded every 15 min after endotracheal intubation up to 180 min.

RESULTS

There was no significant difference of the core temperature between two groups during anesthesia. The relative humidity of HBC group was significantly greater compared to control group (98% vs. 48%, P < 0.01). In both groups, all measured temperatures were significantly lower than that after intubation.

CONCLUSIONS

The use of HBC helped maintain airway humidity, however it did not have the effect to minimize a body temperature drop in major burns.