Inadvertent hypothermia and mortality in postoperative intensive care patients: retrospective audit of 5050 patients

2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM Guideline for Perioperative Cardiovascular Management for Noncardiac Surgery: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM Guideline for Perioperative Cardiovascular Management for Noncardiac Surgery" provides recommendations to guide clinicians in the perioperative cardiovascular evaluation and management of adult patients undergoing noncardiac surgery.

METHODS

A comprehensive literature search was conducted from August 2022 to March 2023 to identify clinical studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (through PubMed), EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline.

STRUCTURE

Recommendations from the "2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery" have been updated with new evidence consolidated to guide clinicians; clinicians should be advised this guideline supersedes the previously published 2014 guideline. In addition, evidence-based management strategies, including pharmacological therapies, perioperative monitoring, and devices, for cardiovascular disease and associated medical conditions, have been developed.

2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM Guideline for Perioperative Cardiovascular Management for Noncardiac Surgery: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM Guideline for Perioperative Cardiovascular Management for Noncardiac Surgery" provides recommendations to guide clinicians in the perioperative cardiovascular evaluation and management of adult patients undergoing noncardiac surgery.

METHODS

A comprehensive literature search was conducted from August 2022 to March 2023 to identify clinical studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (through PubMed), EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline.

STRUCTURE

Recommendations from the "2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery" have been updated with new evidence consolidated to guide clinicians; clinicians should be advised this guideline supersedes the previously published 2014 guideline. In addition, evidence-based management strategies, including pharmacological therapies, perioperative monitoring, and devices, for cardiovascular disease and associated medical conditions, have been developed.

Reducing postoperative hypothermia in infants: Quality improvement in China

BACKGROUND

Unintended postoperative hypothermia in infants is associated with increased mortality and morbidity. We noted consistent hypothermia postoperatively in more than 60% of our neonatal intensive care (NICU) babies. Therefore, we set out to determine whether a targeted quality improvement (QI) project could decrease postoperative hypothermia rates in infants.

OBJECTIVES

Our SMART aim was to reduce postoperative hypothermia (<36.5°C) in infants from 60% to 40% within 6 months.

METHODS

This project was approved by IRB at Guangzhou Women and Children's Medical Center, China. The QI team included multidisciplinary healthcare providers in China and QI experts from Children's Hospital of Philadelphia, USA. The plan-do-study-act (PDSA) cycles included establishing a perioperative-thermoregulation protocol, optimizing the transfer process, and staff education. The primary outcome and balancing measures were, respectively, postoperative hypothermia and hyperthermia (axillary temperature < 36.5°C, >37.5°C). Data collected was analyzed using control charts. The factors associated with a reduction in hypothermia were explored using regression analysis.

RESULTS

There were 295 infants in the project. The percentage of postoperative hypothermia decreased from 60% to 37% over 26 weeks, a special cause variation below the mean on the statistical process control chart. Reduction in hypothermia was associated with an odds of 0.17 (95% CI: 0.06-0.46; p <.001) for compliance with the transport incubator and 0.24 (95% CI: 0.1-0.58; p =.002) for prewarming the OR ambient temperature to 26°C. Two infants had hyperthermia.

CONCLUSIONS

Our QI project reduced postoperative hypothermia without incurring hyperthermia through multidisciplinary team collaboration with the guidance of QI experts from the USA.

Perioperative hypothermia in robotic-assisted thoracic surgery: Incidence, risk factors, and associations with postoperative outcomes

OBJECTIVE

Inadvertent perioperative hypothermia has been associated with poor surgical outcomes. The purpose of this study was to evaluate the incidence and associated postoperative complications of inadvertent perioperative hypothermia in patients undergoing robotic-assisted thoracic surgery lung resections.

METHODS

This was a single-center, retrospective cohort study evaluating all consecutive patients who underwent robotic-assisted thoracic surgery lung resection between January 1, 2021, and November 30, 2022. Temperatures were measured at 5 time points: preprocedure unit, anesthesia induction, 30 minutes postinduction, extubation, and recovery room arrival. Temperature changes were calculated at each interval. Adjusted and unadjusted comparison was performed between those who experienced varying levels of inadvertent perioperative hypothermia (Hypothermia I: <36 °C, Hypothermia II: <35.5 °C, and Hypothermia III: <35 °C) and those who did not.

RESULTS

A total of 313 patients were included, and 201 (64.2%) lobectomies, 50 (16.0%) segmentectomies, and 62 (19.8%) wedge resections were performed. Across all patients, 291 (93.0%) had a temperature less than 36 °C, 195 (62.3%) had a temperature less than 35.5 °C, and 100 (31.9%) had a temperature less than 35.0 °C. Patients experienced significant temperature change at all intervals (P < .001), with the greatest loss occurring during the preprocedure interval (between leaving preprocedure unit and anesthesia induction). On adjusted analysis, patients who experienced inadvertent perioperative hypothermia less than 35.5 °C were older (odds ratio, 1.03; 95% CI, 1.01-1.05), had lower body mass index (odds ratio, 0.95; 95% CI, 0.87-0.98), and had increasing operative time (odds ratio, 1.00; 95% CI, 1.00-1.01). Patients who experienced inadvertent perioperative hypothermia had higher risk-adjusted rates of overall morbidity and infectious postoperative complications.

CONCLUSIONS

The majority of patients undergoing robotic-assisted thoracic surgery lung resections experience some degree of inadvertent perioperative hypothermia and have associated increased rates of 30-day morbidity. Structured and interval-specific interventions should be implemented to decrease rates of inadvertent perioperative hypothermia and subsequent complications.

Factors associated with unintended perianesthesia hypothermia

Background

Our hypothesis was that total intravenous anesthesia (TIVA) is associated with an increase in hypothermia.

Methods

Inclusion criteria were patients from the National Anesthesia Clinical Outcomes Registry undergoing a general anesthetic during 2019. Data collected included patient age, sex, American Society of Anesthesiologists physical status classification system score (ASAPS), duration of anesthetic, use of TIVA, type of procedure, and hypothermia. Continuous variables were compared using Student's t test or Mann Whitney rank sum as appropriate. Mixed effects multiple logistic regression was performed to determine the association between independent variables and hypothermia.

Results

There was a low incidence of hypothermia (1.2%). Patients who became hypothermic were older, had a higher median ASAPS, and had a higher rate of TIVA. TIVA patients had a significantly increased odds for hypothermia when controlling for covariates. Patients undergoing obstetrical, thoracic, or radiological procedures had increased odds for hypothermia. In a matched cohort subset, TIVA was associated with a greater rate and increased odds for hypothermia.

Conclusions

The novel and noteworthy finding was the association between TIVA and perianesthesia hypothermia. Thoracic, radiologic, and obstetrical procedures were associated with greater rates of and odds for hypothermia. Other identified factors can help to stratify patients for risk for hypothermia.

The effectiveness of warming approaches in preventing perioperative hypothermia: Systematic review and meta-analysis

AIM

To assess if experimental warming interventions are superior to routine warming interventions in preventing perioperative hypothermia.

BACKGROUND

Perioperative hypothermia is a critical issue for the complications of surgery. There are various kinds of perioperative warming interventions, including experimental and routine warming interventions.

METHODS

We performed a systematic literature review and meta-analysis for the randomized clinical trials of experimental warming interventions vs. routine warming interventions in the perioperative period.

FINDINGS

A total of 15 studies were included with 983 participants allocated to experimental warming interventions and 939 controls with routine warming interventions, who were receiving a variety of surgeries. The focused outcome was the intraoperative and postoperative body temperature. All included studies were randomized clinical trials. Among the participants receiving operations, the meta-analysis showed that routine warming intervention groups experienced lower intraoperative and postoperative body temperatures compared to the experimental warming groups. The meta-analysis results included positive mean differences, significant tests for overall effect and significant heterogeneity in the random-effects model.

CONCLUSIONS

In spite of significant heterogeneity, experimental warming interventions are likely to demonstrate superior warming effects when compared to routine warming interventions, as shown by the current meta-analysis results of randomized clinical trials.

Thoracic Paravertebral Block Decreased Body Temperature in Thoracoscopic Lobectomy Patients: A Randomized Controlled Trial

Purpose

Thoracic paravertebral block (TPVB) may be highly beneficial for thoracoscopic lobectomy patients, but it may increase the risk of hypothermia. Apart from its anesthetic-reducing effects, this randomized controlled trial aimed to investigate the hypothermic effect of TPVB, and thus optimize its clinical use.

Patients and methods

Adult patients were randomly allocated to two groups: TPVB + general anesthesia (GA) group or GA group. In the TPVB+GA group, the block was performed after GA induction by an experienced but unrelated anesthesiologist. Both the lower esophageal and axillary temperature were recorded at the beginning of surgery (T₀) and every 15 min thereafter (T₁-T₈), and the end of surgery (T_p). The primary outcome was the lower esophageal temperature at T_p. The secondary outcomes included lower esophageal temperature from T₀-T₈ and axillary temperature from T₀-T_p. The total propofol, analgesics, and norepinephrine consumption and the incidence of adverse events were also recorded.

Results

Forty-eight patients were randomly allocated to the TPVB+GA (n=24) and GA (n=24) groups. The core temperature at the end of the surgery was lower in the TPVB+GA group than the GA group (35.90±0.30°C vs 36.35±0.33°C, P<0.001), with a significant difference from 45 min after the surgery began until the end of the surgery (P<0.05). In contrast, the peripheral temperature showed a significant difference at 60 min after the surgery began till the end (P<0.05). TPVB+GA exhibited excellent analgesic and sedative-sparing effects compared to GA alone (P<0.001), though it increased norepinephrine consumption due to hypotension (P<0.001).

Conclusion

Although thorough warming strategies were used, TPVB combined with GA remarkably reduced the body temperature, which is an easily neglected side effect. Further studies on the most effective precautions are needed to optimize the clinical use of TPVB.

Recommendations of the Society of Thoracic Surgery and the Section of Cardiothoracic and Vascular Surgery of the Spanish Society of Anesthesia, Resuscitation and Pain Therapy, for patients undergoing lung surgery included in an intensified recovery program

In recent years, multidisciplinary programs have been implemented that include different actions during the pre, intra and postoperative period, aimed at reducing perioperative stress and therefore improving the results of patients undergoing surgical interventions. Initially, these programs were developed for colorectal surgery and from there they have been extended to other surgeries. Thoracic surgery, considered highly complex, like other surgeries with a high postoperative morbidity and mortality rate, may be one of the specialties that most benefit from the implementation of these programs. This review presents the recommendations made by different specialties involved in the perioperative care of patients who require resection of a lung tumor. Meta-analyzes, systematic reviews, randomized and non-randomized controlled studies, and retrospective studies conducted in patients undergoing this type of intervention have been taken into account in preparing the recommendations presented in this guide. The GRADE scale has been used to classify the recommendations, assessing on the one hand the level of evidence published on each specific aspect and, on the other hand, the strength of the recommendation with which the authors propose its application. The recommendations considered most important for this type of surgery are those that refer to pre-habilitation, minimization of surgical aggression, excellence in the management of perioperative pain and postoperative care aimed at providing rapid postoperative rehabilitation.

Postoperative hypothermia following non-cardiac high-risk surgery: A prospective study of temporal patterns and risk factors

Background and objectives

Hypothermia occurs commonly during surgery and can cause postoperative complications. We aimed to describe the characteristics and outcomes of hypothermia in patients undergoing major surgeries.

Methods

This prospective, observational, multicenter study of a nationally representative sample included all patients over 18 years of age admitted to an intensive care unit (ICU). Thirty ICUs were selected randomly at national level. The main outcome measure was the proportion of patients who developed postoperative hypothermia in the first 24 hours of ICU admission. Patients were divided into three groups based on temperature: <35°C, <36°C, and ≥36°C (no hypothermia). Patients’ characteristics, postoperative complications, and risk factors were evaluated in all groups. To verify whether hypothermia was a strong risk factor for postoperative complications, a Kaplan–Meier curve was generated and adjusted using a Cox regression model.

Results

In total, 738 patients had their temperatures measured. The percentage of patients with temperature <35°C (median [Q1-Q3], 34.7°C [34.3–34.9°C]) was 19.1% (95% confidence interval [CI] = 16.1–22.5) and that of patients with temperature <36°C (median [Q1-Q3], 35.4°C [35.0–35.8°C]) was 64% (95% CI = 58.3–70.0). The percentage of surgical complications was 38.9%. Patients with hypothermia were older, had undergone abdominal surgeries, had undergone procedures of longer duration, and had more comorbidities. A postoperative temperature ≤35°C was an independent risk for composite postoperative complications (hazard ratio = 1.523, 95% CI = 1.15–2.0), especially coagulation and infection.

Conclusions

Inadvertent hypothermia was frequent among patients admitted to the ICU and occurred more likely after abdominal surgery, after a long procedure, in elderly patients, and in patients with a higher number of comorbidities. Low postoperative temperature was associated with postoperative complications.

Development and internal validation of an algorithm to predict intraoperative risk of inadvertent hypothermia based on preoperative data

Intraoperative hypothermia increases perioperative morbidity and identifying patients at risk preoperatively is challenging. The aim of this study was to develop and internally validate prediction models for intraoperative hypothermia occurring despite active warming and to implement the algorithm in an online risk estimation tool. The final dataset included 36,371 surgery cases between September 2013 and May 2019 at the Vienna General Hospital. The primary outcome was minimum temperature measured during surgery. Preoperative data, initial vital signs measured before induction of anesthesia, and known comorbidities recorded in the preanesthetic clinic (PAC) were available, and the final predictors were selected by forward selection and backward elimination. Three models with different levels of information were developed and their predictive performance for minimum temperature below 36 °C and 35.5 °C was assessed using discrimination and calibration. Moderate hypothermia (below 35.5 °C) was observed in 18.2% of cases. The algorithm to predict inadvertent intraoperative hypothermia performed well with concordance statistics of 0.71 (36 °C) and 0.70 (35.5 °C) for the model including data from the preanesthetic clinic. All models were well-calibrated for 36 °C and 35.5 °C. Finally, a web-based implementation of the algorithm was programmed to facilitate the calculation of the probabilistic prediction of a patient's core temperature to fall below 35.5 °C during surgery. The results indicate that inadvertent intraoperative hypothermia still occurs frequently despite active warming. Additional thermoregulatory measures may be needed to increase the rate of perioperative normothermia. The developed prediction models can support clinical decision-makers in identifying the patients at risk for intraoperative hypothermia and help optimize allocation of additional thermoregulatory interventions.

A prognostic model for 1-month mortality in the postoperative intensive care unit

PURPOSES

Recognizing which patients admitted postsurgically to the intensive care unit (ICU) are at greater risk of mortality assists medical staff to identify who will benefit most from the care. We developed a prediction model for the 1-month mortality of postsurgical ICU patients.

METHODS

From May, 2019 to May, 2020, we conducted a prospective cohort study in the postsurgical ICU of a teaching hospital affiliated with our University of Medical Sciences. The outcome was death within 1 month of admission and the predictors were a variety of anthropometric and clinical features. The subjects of this analysis were 805 consecutive adult postsurgical patients with a mean (SD) age of 54.8 (18.9) years.

RESULTS

Overall, the resulted logistic model was well-fitted [χ² (26) = 772.097, p < 0.001, Nagelkerke R² = 0.814] accurate (88%), and specific (92%). The adjusted odds ratio for body temperature was 0.51, p < 0.001. Patients with comorbidities and those undergoing multiple operations were at a greater risk of mortality, odds = 10.00 and 10.65 (both p < 0.001).

CONCLUSIONS

Higher body temperature at the time of postoperative ICU admission is a protective factor against 1-month mortality. Our study found that patients with several comorbidities and those who have undergone multiple operations are at a greater risk of a poor outcome.

Relationship Between First 24-h Mean Body Temperature and Clinical Outcomes of Post-cardiac Surgery Patients

Background: This study was aimed to investigate the relationship between first 24-h mean body temperature and clinical outcomes of post cardiac surgery patients admitted to intensive care unit (ICU) in a large public clinical database.

Methods: This is a retrospectively observational research of MIMIC III dataset, a total of 6,122 patients included. Patients were divided into 3 groups according to the distribution of body temperature. Multivariate cox analysis and logistic regression analysis were used to investigate the association between abnormal temperature, and clinical outcomes.

Results: Hypothermia (<36°C) significantly associated with increasing in-hospital mortality (HR 1.665, 95%CI 1.218–2.276; p = 0.001), 1-year mortality (HR 1.537, 95% CI 1.205–1.961; p = 0.001), 28-day mortality (HR 1.518, 95% CI 1.14–2.021; p = 0.004), and 90-day mortality (HR 1.491, 95% CI 1.144–1.943; p = 0.003). No statistical differences were observed between short-term or long-term mortality and hyperthermia (>38°C). Hyperthermia was related to the extended length of ICU stay (p < 0.001), and hospital stay (p < 0.001).

Conclusion: Hypothermia within 24h after ICU admission was associated with the increased mortality of post cardiac surgery patients. Enhanced monitoring of body temperature within 24h after cardiac surgery should be taken into account for improving clinical outcomes.

Recommendations of the Society of Thoracic Surgery and the Section of Cardiothoracic and Vascular Surgery of the Spanish Society of Anesthesia, Resuscitation and Pain Therapy, for patients undergoing lung surgery included in an intensified recovery program

In recent years, multidisciplinary programs have been implemented that include different actions during the pre, intra and postoperative period, aimed at reducing perioperative stress and therefore improving the results of patients undergoing surgical interventions. Initially, these programs were developed for colorectal surgery and from there they have been extended to other surgeries. Thoracic surgery, considered highly complex, like other surgeries with a high postoperative morbidity and mortality rate, may be one of the specialties that most benefit from the implementation of these programs. This review presents the recommendations made by different specialties involved in the perioperative care of patients who require resection of a lung tumor. Meta-analyses, systematic reviews, randomized and non-randomized controlled studies, and retrospective studies conducted in patients undergoing this type of intervention have been taken into account in preparing the recommendations presented in this guide. The GRADE scale has been used to classify the recommendations, assessing on the one hand the level of evidence published on each specific aspect and, on the other hand, the strength of the recommendation with which the authors propose its application. The recommendations considered most important for this type of surgery are those that refer to pre-habilitation, minimization of surgical aggression, excellence in the management of perioperative pain and postoperative care aimed at providing rapid postoperative rehabilitation.

Accuracy of zero-heat-flux thermometry and bladder temperature measurement in critically ill patients

Core temperature (T_Core) monitoring is essential in intensive care medicine. Bladder temperature is the standard of care in many institutions, but not possible in all patients. We therefore compared core temperature measured with a zero-heat flux thermometer (T_ZHF) and with a bladder catheter (T_Bladder) against blood temperature (T_Blood) as a gold standard in 50 critically ill patients in a prospective, observational study. Every 30 min T_Blood, T_Bladder and T_ZHF were documented simultaneously. Bland–Altman statistics were used for interpretation. 7018 pairs of measurements for the comparison of T_Blood with T_ZHF and 7265 pairs of measurements for the comparison of T_Blood with T_Bladder could be used. T_Bladder represented T_Blood more accurate than T_ZHF. In the Bland Altman analyses the bias was smaller (0.05 °C vs. − 0.12 °C) and limits of agreement were narrower (0.64 °C to − 0.54 °C vs. 0.51 °C to – 0.76 °C), but not in clinically meaningful amounts. In conclusion the results for zero-heat-flux and bladder temperatures were virtually identical within about a tenth of a degree, although T_ZHF tended to underestimate T_Blood. Therefore, either is suitable for clinical use.

German Clinical Trials Register, DRKS00015482, Registered on 20th September 2018, http://apps.who.int/trialsearch/Trial2.aspx?TrialID=DRKS00015482.

Incidence of Unintentional Intraoperative Hypothermia in Pediatric Scoliosis Surgery and Associated Preoperative Risk Factors

Introduction

Intraoperative hypothermia is associated with perioperative complications such as blood loss and wound infection. Thus, perioperative heat retention methods to prevent perioperative hypothermia such as providing a warmed blanket and active patients' warming are important. Although major surgery and pediatric patient age are noted as risk factors, only a few studies focus on hypothermia as an intraoperative complication in pediatric scoliosis surgery. The aim of this study is to investigate the incidence of intraoperative hypothermia in pediatric scoliosis surgery and the associated preoperative risk factors.

Methods

We retrospectively reviewed the records of pediatric patients who underwent posterior spinal fusion at a single institution between 2015 and 2019. We recorded the background data, perioperative data, lowest recorded core temperature, and perioperative complications. Patients were divided into those whose temperature decreased below 36°C (Group H) and those who maintained a temperature of 36°C or greater (Group N) during surgery. We compared the two groups and performed multivariate analysis to identify preoperative risk factors for intraoperative hypothermia.

Results

A total of 103 patients underwent posterior spinal fusion; 56 for adolescent idiopathic scoliosis and 47 for neuromuscular scoliosis. Hypothermia was observed in 40 patients (38.8%). Group H had more non-adolescent idiopathic scoliosis (AIS) patients, lower mean body mass index, greater mean blood loss, greater number of fused vertebrae, larger preoperative Cobb angle, and lower initial core body temperature (immediately after induction of anesthesia). On multivariate analysis, a diagnosis of neuromuscular scoliosis, a lower body mass index, and a lower initial core body temperature were identified as independent risk factors for intraoperative hypothermia.

Conclusions

The incidence of hypothermia in pediatric posterior scoliosis surgery is 38.8%. Diagnosis of non-AIS, lower body mass index, and lower core body temperature at the time of anesthesia induction are preoperative risk factors for intraoperative hypothermia.

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.

Intraoperative core temperature monitoring: accuracy and precision of zero-heat flux heated controlled servo sensor compared with esophageal temperature during major surgery; the ESOSPOT study

Monitoring of intraoperative core temperature is strongly recommended to reduce the risk of perioperative thermic imbalance and related complications. The zero-heat-flux sensor (3M Bair Hugger Temperature monitoring system, ZHF), measures core temperature in a non-invasive manner. This study was aimed at comparing accuracy and precision of the ZHF sensor compared to the esophageal thermometer. Patients scheduled for major elective abdominal or urologic surgery were considered eligible for enrollment. Core body temperature was measured using both an esophageal probe (T_ESO) and a ZHF sensor (T_ZHF) every 15 min from induction until the end of general anaesthesia. A Bland-Altman plot for repeated measures was performed. The proportion of measurements within ± 0.5 °C was estimated; from a clinical point of view, a proportion greater than 90% was considered sufficiently accurate. Lin's concordance correlation coefficient (CCC) for repeated measures were calculated. To evaluate association between the two methods, a generalized estimating equation (GEE) simple linear regression model, was elaborated. A GEE multiple regression model was also performed in order to adjust the estimate of the association between measurements from surgical and patient's features. Ninety-nine patients were enrolled. Bland-Altman plot bias was 0.005 °C with upper and lower limits of agreement for repeated measures of 0.50 °C and - 0.49 °C. The percentage of measurements within 0.5 °C of the reference value was 97.98% (95% confidence interval 92.89-99.75%), indicating a clinically sufficient agreement between the two methods. This was also confirmed by a CCC for repeated measures of 0.89 (95% CI 0.80 to 0.94). The GEE simple regression model (slope value of 0.77) was not significantly influenced by any patient or surgical variables. According to GEE multiple regression model results, the explored patient- and surgery-related variables did not influence the association between methods. ZHF sensor has shown a clinically acceptable accuracy and precision for body core temperature monitoring during elective major surgery. CLINICAL TRIALS: Clinical trial number: NCT03820232.

Association Between Postoperative Body Temperature and All-Cause Mortality After Off-Pump Coronary Artery Bypass Graft Surgery: A Retrospective Observational Study

BACKGROUND

Inadvertent perioperative hypothermia is common in patients undergoing off-pump coronary artery bypass grafting (OPCAB). We investigated the association between early postoperative body temperature and all-cause mortality in patients undergoing OPCAB.

METHODS

We reviewed the electronic medical records of 1714 patients who underwent OPCAB (median duration of follow-up, 47 months). Patients were divided into 4 groups based on body temperature at the time of intensive care unit admission after surgery (moderate-to-severe hypothermia, <35.5°C; mild hypothermia, 35.5°C-36.5°C; normothermia, 36.5°C-37.5°C; and hyperthermia, ≥37.5°C). Cox proportional hazards models were used to assess the association between body temperature and all-cause mortality. The association between early postoperative changes in body temperature and all-cause mortality was also assessed by dividing the patients into 4 categories according to the body temperature measured at postoperative intensive care unit admission and the average body temperature during the first 3 postoperative days.

RESULTS

Compared to the normothermia group, the adjusted hazard ratios of all-cause mortality were 2.030 (95% confidence interval, 1.407-2.930) in the moderate-to-severe hypothermia group and 1.445 (95% confidence interval, 1.113-1.874) in the mild hypothermia group. Patients who were hypothermic at postoperative intensive care unit admission but attained normothermia thereafter were at a lower risk of all-cause mortality compared to patients who did not regain normothermia (adjusted hazard ratio, 0.631; 95% confidence interval, 0.453-0.878), while they were still at a higher risk of all-cause mortality than those who were consistently normothermic (adjusted hazard ratio, 1.435; 95% confidence interval, 1.090-1.890).

CONCLUSIONS

Even mild early postoperative hypothermia was associated with all-cause mortality after OPCAB. Patients who regained normothermia postoperatively were at lower risk of all-cause mortality compared to those who did not.

Prevention of inadvertent perioperative hypothermia - Guideline compliance in German hospitals

Patients undergoing elective surgery are at risk for inadvertent postoperative hypothermia, defined as a core body temperature below 36°C. This study was conducted to investigate the acceptance of the recommendations of the German S3 Guideline, in particular with respect to the concept of pre-warming and sublingual temperature measurement. The main focus was to gather data concerning the postoperative core temperature and the frequency of perioperative hypothermia in patients receiving a pre-warming regime and those without. The study team investigated the local concept and measures employed to avoid inadvertent perioperative hypothermia with respect to defined outcome parameters following a specific protocol. In summary, the study hospitals vary greatly in their perioperative processes to prevent postoperative hypothermia. However, each hospital has a strategy to prevent hypothermia and was more or less successful in keeping its patients normothermic during the perioperative process. Our data could not demonstrate major differences between hospitals in the implementation strategy to prevent perioperative hypothermia in regard to the hospital size. The results of our study suggest a wide-spread acceptance, as no postoperative hypothermia was detected in a cohort of 431 patients.

Association of Immediate Postoperative Temperature in the Surgical Intensive Care Unit with 1-Year Mortality: Retrospective Analysis Using Digital Axillary Thermometers

Background

Postoperative body temperature is closely associated with prognosis although there is limited research regarding this association at Postoperative intensive care unit (ICU) admission. Furthermore, no studies have used digital axillary thermometers to measure Postoperative body temperature. This study investigated the association between mortality and Postoperative temperature measured using a digital axillary thermometer within 10 minutes after ICU admission.

Methods

This retrospective observational study evaluated data from adult patients admitted to an ICU after elective or emergency surgery. The primary outcome was 1-year mortality after ICU admission. Multivariable logistic regression analysis with restricted cubic splines was used to evaluate the association between temperature and outcomes.

Results

We evaluated data from 5,868 patients admitted between January 1, 2013 and May 31, 2016, including 5,311 patients (90.5%) who underwent noncardiovascular surgery and 557 patients (9.5%) who underwent cardiovascular surgery. Deviation from the median temperature (36.6℃) was associated with increases in 1-year mortality (≤ 36.6℃: linear coefficient, -0.531; P<0.001 and ≥36.6℃: spline coefficient, 0.756; P<0.001). Similar statistically significant results were observed in the noncardiovascular surgery group, but not in the cardiovascular surgery group.

Conclusions

An increase or decrease in body temperature (vs. 36.6℃) measured using digital axillary thermometers within 10 minutes of Postoperative ICU admission was associated with increased 1-year mortality. However, no significant association was observed after cardiovascular surgery. These results suggest that Postoperative temperature is associated with longterm mortality in patients admitted to the surgical ICU in the Postoperative period.

Factors that influence effective perioperative temperature management by anesthesiologists: a qualitative study using the Theoretical Domains Framework

PURPOSE

Inadvertent perioperative hypothermia (IPH) is associated with a range of adverse outcomes. Safe and effective warming techniques exist to prevent IPH; however, IPH remains common. This study aimed to identify factors that anesthesiologists perceive may influence temperature management during the perioperative period.

METHODS

After Research Ethics Board approval, semi-structured interviews were conducted with staff anesthesiologists at a Canadian academic hospital. An interview guide based on the Theoretical Domains Framework (TDF) was used to capture 14 theoretical domains that may influence temperature management. The interview transcripts were coded using direct content analysis to generate specific beliefs and to identify relevant TDF domains perceived to influence temperature management behaviour.

RESULTS

Data saturation was achieved after 15 interviews. The following nine theoretical domains were identified as relevant to designing an intervention for practices in perioperative temperature management: knowledge, beliefs about capabilities, beliefs about consequences, reinforcement, memory/attention/decision-making, environmental context and resources, social/professional role/identity, social influences, and behavioural regulation. Potential target areas to improve temperature management practices include interventions that address information needs about individual temperature management behaviour as well as patient outcome (feedback), increasing awareness of possible temperature management strategies and guidelines, and a range of equipment and surgical team dynamics that influence temperature management.

CONCLUSION

This study identified several potential target areas for future interventions from nine of the TDF behavioural domains that anesthesiologists perceive to drive their temperature management practices. Future interventions that aim to close the evidence-practice gap in perioperative temperature management may include these targets.

Inadvertent hypothermia and mortality in critically ill adults: Systematic review and meta-analysis

OBJECTIVE

Considering that inadvertent hypothermia (IH) is common in Intensive Care Unit (ICU) patients and can be followed by severe complications, this systematic review identified, appraised and synthesised the published literature about the association between IH and mortality in adults admitted to the ICU.

DATA SOURCES

By using key terms, literature searches were conducted in Pubmed, CINAHL, Cochrane Library, Web of Science and EMBASE.

REVIEW METHODS

According to PRISMA guidelines, articles published between 1980-2016 in English-language, peer-reviewed journals were considered. IH was defined as core temperature of <36.5°C or lower, present on ICU admission or manifested during ICU stay. Outcome measure included ICU, hospital or 28-day mortality. Selected cohort studies were evaluated with the Newcastle-Ottawa Scale. Extracted data were summarised in tables and synthesised qualitatively and quantitatively, with adjusted odds ratios (ORs) for mortality being combined in meta-analyses.

RESULTS

Eighteen observational studies met inclusion criteria. All of them had high methodological quality. In twelve out of fifteen studies, unadjusted mortality was significantly higher in hypothermic patients compared to non-hypothermic ones. Likewise, in thirteen out of sixteen studies, IH or lowest core temperature was independently associated with significantly higher mortality. High severity and long duration of IH were also associated with higher mortality. Mortality was significantly higher in patients with core temperature <36.0°C (pooled OR 2.093, 95% CI 1.704-2.570), and in those with core temperature <35.0°C (pooled OR 2.945, 95% CI 2.166-4.004).

CONCLUSIONS

These findings indicate that IH predicts mortality in critically ill adults and pose suspicion that this may contribute to adverse patient outcome.

The Nurse Anesthetists' Adherence to Swedish National Recommendations to Maintain Normothermia in Patients During Surgery

PURPOSE

The aim of this study was to determine if nurse anesthetists (NAs) have access, knowledge, and adhere to recommended guidelines to maintain normal body temperature during the perioperative period.

DESIGN

A descriptive survey design.

METHODS

Questionnaires were sent to heads of the department (n = 56) and NAs in the operating departments in Sweden.

FINDING

The level of access to the recommendations is high, but only one third of the operating departments have included the recommendations in their own local guidelines. The NAs' adherence was low, between 5% and 67%, and their knowledge levels were 57% to 60%.

CONCLUSIONS

A high level of knowledge, access, and adherence are important for the organization of operating departments to prevent barriers against implementation of new recommendations or guidelines. There are needs for education about patients' heat loss due to redistribution and clear recommendations.

Elevated Modified Shock Index Within 24 Hours of ICU Admission Is an Early Indicator of Mortality in the Critically Ill

PURPOSE

To assess whether exposure to modified shock index (MSI) in the first 24 hours of intensive care unit (ICU) admission is associated with increased in-hospital mortality.

METHODS

Adult critically ill patients were included in a case-control design with 1:2 matching. Cases (death) and controls (alive) were abstracted by a reviewer blinded to exposure status (MSI). Cases were matched to controls on 3 factors-age, end-stage renal disease, and ICU admission diagnosis.

RESULTS

Eighty-three cases and 159 controls were included. On univariate analysis, lorazepam administration (odds ratio [OR]: 5.75, confidence interval [CI] = 2.28-14.47; P ≤ .01), shock requiring vasopressors (OR: 3.62, CI = 1.77-7.40; P ≤ .01), maximum MSI (OR: 2.77 per unit, CI = 1.63-4.71; P ≤ .001), and elevated acute physiologic and chronic health evaluation (APACHE) III score at 1 hour (OR: 1.41 per 10 units, CI = 1.19-1.66; P ≤ .001) were associated with mortality. Maximum MSI (OR: 1.93 per unit, CI = 1.07-3.48, P = .03) and APACHE III score at 1 hour (OR: 1.29 per 10 units, CI = 1.09-1.53; P = .003) remained significant with mortality in the multivariate analysis. The optimal cutoff point for high MSI and mortality was 1.8.

CONCLUSION

Critically ill patients who demonstrate an elevated MSI within the first 24 hours of ICU admission have a significant mortality risk. Given that MSI is easily calculated at the bedside, clinicians may institute interventions earlier which could improve survival.

Unexpectedly high incidence of hypothermia before induction of anesthesia in elective surgical patients

STUDY OBJECTIVE

Perioperative hypothermia is a frequently observed phenomenon of general anesthesia and is associated with adverse patient outcome. Recently, a significant influence of core temperature before induction of anesthesia has been reported. However, there are still little existing data on core temperature before induction of anesthesia and no data regarding potential risk factors for developing preoperative hypothermia. The purpose of this investigation was to estimate the incidence of hypothermia before anesthesia and to determine if certain factors predict its incidence.

DESIGN/SETTING/PATIENTS

Data from 7 prospective studies investigating core temperature previously initiated at our department were analyzed. Patients undergoing a variety of elective surgical procedures were included.

INTERVENTIONS/MEASUREMENTS

Core temperature was measured before induction of anesthesia with an oral (314 patients), infrared tympanic (143 patients), or tympanic contact thermometer (36 patients). Available potential predictors included American Society of Anesthesiologists status, sex, age, weight, height, body mass index, adipose ratio, and lean body weight. Association with preoperative hypothermia was assessed separately for each predictor using logistic regression. Independent predictors were identified using multivariable logistic regression.

MAIN RESULTS

A total of 493 patients were included in the study. Hypothermia was found in 105 patients (21.3%; 95% confidence interval, 17.8%-25.2%). The median core temperature was 36.3°C (25th-75th percentiles, 36.0°C-36.7°C). Two independent factors for preoperative hypothermia were identified: male sex and age (>52years).

CONCLUSIONS

As a consequence of the high incidence of hypothermia before anesthesia, measuring core temperature should be mandatory 60 to 120minutes before induction to identify and provide adequate treatment to hypothermic patients.

Novel Zero-Heat-Flux Deep Body Temperature Measurement in Lower Extremity Vascular and Cardiac Surgery

OBJECTIVE

The aim of this study was to compare deep body temperature obtained using a novel noninvasive continuous zero-heat-flux temperature measurement system with core temperatures obtained using conventional methods.

DESIGN

A prospective, observational study.

SETTING

Operating room of a university hospital.

PARTICIPANTS

The study comprised 15 patients undergoing vascular surgery of the lower extremities and 15 patients undergoing cardiac surgery with cardiopulmonary bypass.

INTERVENTIONS

Zero-heat-flux thermometry on the forehead and standard core temperature measurements.

MEASUREMENTS AND MAIN RESULTS

Body temperature was measured using a new thermometry system (SpotOn; 3M, St. Paul, MN) on the forehead and with conventional methods in the esophagus during vascular surgery (n = 15), and in the nasopharynx and pulmonary artery during cardiac surgery (n = 15). The agreement between SpotOn and the conventional methods was assessed using the Bland-Altman random-effects approach for repeated measures. The mean difference between SpotOn and the esophageal temperature during vascular surgery was+0.08°C (95% limit of agreement -0.25 to+0.40°C). During cardiac surgery, during off CPB, the mean difference between SpotOn and the pulmonary arterial temperature was -0.05°C (95% limits of agreement -0.56 to+0.47°C). Throughout cardiac surgery (on and off CPB), the mean difference between SpotOn and the nasopharyngeal temperature was -0.12°C (95% limits of agreement -0.94 to+0.71°C). Poor agreement between the SpotOn and nasopharyngeal temperatures was detected in hypothermia below approximately 32°C.

CONCLUSIONS

According to this preliminary study, the deep body temperature measured using the zero-heat-flux system was in good agreement with standard core temperatures during lower extremity vascular and cardiac surgery. However, agreement was questionable during hypothermia below 32°C.

Incidence of Inadvertent Intraoperative Hypothermia and Its Risk Factors in Patients Undergoing General Anesthesia in Beijing: A Prospective Regional Survey

Background/Objective

Inadvertent intraoperative hypothermia (core temperature <36⁰ C) is a recognized risk in surgery and has adverse consequences. However, no data about this complication in China are available. Our study aimed to determine the incidence of inadvertent intraoperative hypothermia and its associated risk factors in a sample of Chinese patients.

Methods

We conducted a regional cross-sectional survey in Beijing from August through December, 2013. Eight hundred thirty patients who underwent various operations under general anesthesia were randomly selected from 24 hospitals through a multistage probability sampling. Multivariate logistic regression analyses were applied to explore the risk factors of developing hypothermia.

Results

The overall incidence of intraoperative hypothermia was high, 39.9%. All patients were warmed passively with surgical sheets or cotton blankets, whereas only 10.7% of patients received active warming with space heaters or electric blankets. Pre-warmed intravenous fluid were administered to 16.9% of patients, and 34.6% of patients had irrigation of wounds with pre-warmed fluid. Active warming (OR = 0.46, 95% CI 0.26–0.81), overweight or obesity (OR = 0.39, 95% CI 0.28–0.56), high baseline core temperature before anesthesia (OR = 0.08, 95% CI 0.04–0.13), and high ambient temperature (OR = 0.89, 95% CI 0.79–0.98) were significant protective factors for hypothermia. In contrast, major-plus operations (OR = 2.00, 95% CI 1.32–3.04), duration of anesthesia (1–2 h) (OR = 3.23, 95% CI 2.19–4.78) and >2 h (OR = 3.44, 95% CI 1.90–6.22,), and intravenous un-warmed fluid (OR = 2.45, 95% CI 1.45–4.12) significantly increased the risk of hypothermia.

Conclusions

The incidence of inadvertent intraoperative hypothermia in Beijing is high, and the rate of active warming of patients during operation is low. Concern for the development of intraoperative hypothermia should be especially high in patients undergoing major operations, requiring long periods of anesthesia, and receiving un-warmed intravenous fluids.

Hypothermia in Adult ICUs: Changing Incidence But Persistent Risk Factor for Mortality

BACKGROUND

This study examined whether hypothermia (< 36.0°C) incidence among critically ill patients varied over time, the determinants of change, and the associated risk for ICU mortality.

METHODS

Interrupted time series analysis among adults admitted to ICUs in Calgary, Canada over 8.5 years. Changes in the incidence of hypothermia within the first 24 hours of ICU admission were modelled using segmented regression.

RESULTS

Among 15,291 first admissions to ICU, hypothermia incidence decreased from 29% to 21% during the study period. Implementation of a new temporal artery thermometer (TAT) was associated with the majority of the decrease in incidence (10%; 95% CI 7.1-13%; P < .0001). However, subgroup analysis revealed important differences between medical and surgical patients. Hypothermia incidence decreased among surgical patients before TAT implementation (0.4% per quarter, 95% CI 0.1-0.7%, P = .009), but not after, whereas in medical patients, the incidence increased after (1.0% per quarter, 95% CI 0.6-1.4%, P < .0001) but not before TAT implementation. Segmented logistic regression suggested that increases in the proportion of patients with non-traumatic neurologic admission diagnoses were associated with hypothermia incidence among medical patients, whereas there was no measurable clinical factor associated with the observed time trends among surgical patients. Hypothermia at ICU admission was independently associated with ICU mortality in medical and surgical patients throughout the entire study.

CONCLUSION

The incidence of hypothermia at ICU admission was dependent on medical versus surgical status, and the method of non-invasive temperature measurement, but was persistently associated with ICU mortality.

Body temperature abnormalities in non-neurological critically ill patients: a review of the literature

Body temperature abnormalities, which occur because of several infectious and non-infectious etiologies, are among the most commonly noted symptoms of critically ill patients. These abnormalities frequently trigger changes in patient management. The purpose of this article was to review the contemporary literature investigating the definition and occurrence of body temperature abnormalities in addition to their impact on illness severity and mortality in critically ill non-neurological patients, particularly in patients with severe sepsis. Reports on the influence of fever on outcomes are inconclusive, and the presence of fever per se may not contribute to increased mortality in critically ill patients. In patients with severe sepsis, the impacts of elevated body temperature and hypothermia on mortality and the severity of physiologic decline are different. Hypothermia is significantly associated with an increased risk of mortality. In contrast, elevated body temperature may not be associated with increased disease severity or risk of mortality. In patients with severe sepsis, the effect of fever and fever control on outcomes requires further research.

The impact of body temperature abnormalities on the disease severity and outcome in patients with severe sepsis: an analysis from a multicenter, prospective survey of severe sepsis

INTRODUCTION

Abnormal body temperatures (Tb) are frequently seen in patients with severe sepsis. However, the relationship between Tb abnormalities and the severity of disease is not clear. This study investigated the impact of Tb on disease severity and outcomes in patients with severe sepsis.

METHODS

We enrolled 624 patients with severe sepsis and grouped them into 6 categories according to their Tb at the time of enrollment. The temperature categories (≤ 35.5 °C, 35.6-36.5 °C, 36.6-37.5 °C, 37.6-38.5 °C, 38.6-39.5 °C, ≥ 39.6 °C) were based on the temperature data of the Acute Physiology and Chronic Health Evaluation II (APACHE II) scoring. We compared patient characteristics, physiological data, and mortality between groups.

RESULTS

Patients with Tb of ≤ 36.5 °C had significantly worse sequential organ failure assessment (SOFA) scores when compared with patients with Tb >37.5 °C on the day of enrollment. Scores for APACHE II were also higher in patients with Tb ≤ 35.5 °C when compared with patients with Tb >36.5 °C. The 28-day and hospital mortality was significantly higher in patients with Tb ≤ 36.5 °C. The difference in mortality rate was especially noticeable when patients with Tb ≤ 35.5 °C were compared with patients who had Tb of >36.5 °C. Although mortality did not relate to Tb ranges of ≥ 37.6 °C as compared to reference range of 36.6-37.5 °C, relative risk for 28-day mortality was significantly greater in patients with 35.6-36.5 °C and ≤ 35.5 °C (odds ratio; 2.032, 3.096, respectively). When patients were divided into groups based on the presence (≤ 36.5 °C, n = 160) or absence (>36.5 °C, n = 464) of hypothermia, disseminated intravascular coagulation (DIC) as well as SOFA and APACHE II scores were significantly higher in patients with hypothermia. Patients with hypothermia had significantly higher 28-day and hospital mortality rates than those without hypothermia (38.1% vs. 17.9% and 49.4% vs. 22.6%, respectively). The presence of hypothermia was an independent predictor of 28-day mortality, and the differences between patients with and without hypothermia were observed irrespective of the presence of septic shock.

CONCLUSIONS

In patients with severe sepsis, hypothermia (Tb ≤ 36.5 °C) was associated with increased mortality and organ failure, irrespective of the presence of septic shock.

TRIAL REGISTRATION

UMIN-CTR ID UMIN000008195.

[Efficacy of a novel warming blanket: prospective randomized trial]

BACKGROUND

Perioperative hypothermia is a common complication of general anesthesia and occurs in up to 50 % of patients during ear, nose and throat (ENT) surgery. In this prospective, randomized controlled study the hypothesis that a new conductive warming blanket (Barrier® EasyWarm®, Mölnlycke Health Care Erkrath, Germany) is better in reducing the incidence of perioperative hypothermia in ENT surgery than insulation with a conventional hospital duvet alone was tested.

MATERIALS AND METHODS

After approval of the local ethics committee and written informed consent 80 patients with a planned procedure time between 1 and 3 h were recruited. Anesthesia was induced and maintained using propofol, remifentanil and rocuronium and the core temperature was measured using an esophageal temperature probe. Patients in the study group were warmed at least 30 min prior to induction of anesthesia using the novel warming blanket (Barrier® EasyWarm®) and patients in the control group were insulated with a standard hospital duvet. Data were tested using Fisher's exact test, Student's t-test or the Mann-Whitney U-test as appropriate. Time-dependent changes in core temperature were evaluated using repeated measures analysis of variance (ANOVA) and post hoc Scheffé's test. Results are expressed as mean ± SD or as median and interquartile range (IQR) as appropriate. A p < 0.05 was considered to be statistically significant.

RESULTS

The ANOVA did not identify a significantly higher core temperature in the study group at any time point. Furthermore, Fisher's exact test showed no differences in the incidence of intraoperative (12 out of 29 versus 10 out of 32 patients, p = 0.44) or postoperative hypothermia (12 out of 29 versus 9 out of 32 patients, p = 0.30) between the groups. No adverse effects were observed.

CONCLUSIONS

In the studied patient group the new conductive warming blanket (Barrier® EasyWarm®) showed no superiority compared to conventional thermal insulation alone.

Severe hypothermia increases the risk for intensive care unit-acquired infection

BACKGROUND

Although hypothermia is widely accepted as a risk factor for subsequent infection in surgical patients, it has not been well defined in medical patients. We sought to assess the risk of acquiring intensive care unit (ICU)--acquired infection after hypothermia among medical ICU patients.

METHODS

Adults (≥18 years) admitted to French ICUs for at least 2 days between April 2000 and November 2010 were included. Surgical patients were excluded. Patient were classified as having had mild hypothermia (35.0°C-35.9°C), moderate hypothermia (32°C-34.9°C), or severe hypothermia (<32°C), and were followed for the development of pneumonia or bloodstream infection until ICU discharge.

RESULTS

A total of 6237 patients were included. Within the first day of admission, 648 (10%) patients had mild hypothermia, 288 (5%) patients had moderate hypothermia, and 45 (1%) patients had severe hypothermia. Among the 5256 patients who did not have any hypothermia at day 1, subsequent hypothermia developed in 868 (17%), of which 673 (13%), 176 (3%), and 19 (<1%) patients had lowest temperatures of 35.0°C-35.9°C, 32.0°C-34.9°C, and <32°C, respectively. During the course of ICU admission, 320 (5%) patients developed ICU-acquired bloodstream infection and 724 (12%) patients developed ICU-acquired pneumonia. After controlling for confounding variables in multivariable analyses, severe hypothermia was found to increase the risk for subsequent ICU-acquired infection, particularly in patients who did not present with severe sepsis or septic shock.

CONCLUSIONS

The presence of severe hypothermia is a risk factor for development of ICU-acquired infection in medical patients.

Quality of interhospital transport of the critically ill: impact of a Mobile Intensive Care Unit with a specialized retrieval team

Introduction

In order to minimize the additional risk of interhospital transport of critically ill patients, we started a mobile intensive care unit (MICU) with a specialized retrieval team, reaching out from our university hospital-based intensive care unit to our adherence region in March 2009. To evaluate the effects of this implementation, we performed a prospective audit comparing adverse events and patient stability during MICU transfers with our previous data on transfers performed by standard ambulance.

Methods

All transfers performed by MICU from March 2009 until December 2009 were included. Data on 14 vital variables were collected at the moment of departure, arrival and 24 hours after admission. Variables before and after transfer were compared using the paired-sample T-test. Major deterioration was expressed as a variable beyond a predefined critical threshold and was analyzed using the McNemar test and the Wilcoxon Signed Ranks test. Results were compared to the data of our previous prospective study on interhospital transfer performed by ambulance.

Results

A total of 74 interhospital transfers of ICU patients over a 10-month period were evaluated. An increase of total number of variables beyond critical threshold at arrival, indicating a worsening of condition, was found in 38 percent of patients. Thirty-two percent exhibited a decrease of one or more variables beyond critical threshold and 30% showed no difference. There was no correlation between patient status at arrival and the duration of transfer or severity of disease. ICU mortality was 28%. Systolic blood pressure, glucose and haemoglobin were significantly different at arrival compared to departure, although significant values for major deterioration were never reached. Compared to standard ambulance transfers of ICU patients, there were less adverse events: 12.5% vs. 34%, which in the current study were merely caused by technical (and not medical) problems. Although mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was significantly higher, patients transferred by MICU showed less deterioration in pulmonary parameters during transfer than patients transferred by standard ambulance.

Conclusions

Transfer by MICU imposes less risk to critically ill patients compared to transfer performed by standard ambulance and has, therefore, resulted in an improved quality of interhospital transport of ICU patients in the north-eastern part of the Netherlands.

[Preoperative prewarming as a routine measure. First experiences]

BACKGROUND

Despite the broad application of intraoperative warming new studies still show a high incidence of perioperative hypothermia. Therefore a prewarming program in the preoperative holding area was started.

METHODS

The efficacy of the prewarming program was assessed with an accompanying quality assurance check sheet over a period of 3 months.

RESULTS

During the 3 month test period 127 patients were included. The median length from arrival in the holding area to beginning prewarming was 6 min and the average duration of prewarming was 46±38 min. During prewarming the core temperature rose by 0.3±0.4°C to 37.1±0.5°C and decreased to 36.3±0.5°C after induction of anesthesia. At the end of the operation the core temperature was 36.4±0.5°C and 14% of the patients were hypothermic.

CONCLUSION

These data allow 2 conclusions: 1. Prewarming in the holding area is possible with a sufficient duration. 2. Prewarming is highly efficient even when performed over a relatively short duration.

Temporal Artery versus Bladder Thermometry during Adult Medical-Surgical Intensive Care Monitoring: An Observational Study

Background

We sought to evaluate agreement between a new and widely implemented method of temperature measurement in critical care, temporal artery thermometry and an established method of core temperature measurement, bladder thermometry as performed in clinical practice.

Methods

Temperatures were simultaneously recorded hourly (n = 736 observations) using both devices as part of routine clinical monitoring in 14 critically ill adult patients with temperatures ranging ≥1°C prior to consent.

Results

The mean difference between temporal artery and bladder temperatures measured was -0.44°C (95% confidence interval, -0.47°C to -0.41°C), with temporal artery readings lower than bladder temperatures. Agreement between the two devices was greatest for normothermia (36.0°C to < 38.3°C) (mean difference -0.35°C [95% confidence interval, -0.37°C to -0.33°C]). The temporal artery thermometer recorded higher temperatures during hypothermia (< 36°C) (mean difference 0.66°C [95% confidence interval, 0.53°C to 0.79°C]) and lower temperatures during hyperthermia (≥38.3°C) (mean difference -0.90°C [95% confidence interval, -0.99°C to -0.81°C]). The sensitivity for detecting fever (core temperature ≥38.3°C) using the temporal artery thermometer was 0.26 (95% confidence interval, 0.20 to 0.33), and the specificity was 0.99 (95% confidence interval, 0.98 to 0.99). The positive likelihood ratio for fever was 24.6 (95% confidence interval, 10.7 to 56.8); the negative likelihood ratio was 0.75 (95% confidence interval, 0.68 to 0.82).

Conclusions

Temporal artery thermometry produces somewhat surprising disagreement with an established method of core temperature measurement and should not to be used in situations where body temperature needs to be measured with accuracy.