Effect of administration of pre-warmed intravenous fluids on the frequency of hypothermia following spinal anesthesia for Cesarean delivery

The Effects of Actively Warming the Patient on Maternal and Infant Well-Being in a Cesarean Section Operation

PURPOSE

Intraoperative warming is recommended for surgical patients under anesthesia, but there are insufficient studies on this topic in cesarean delivery patients under spinal anesthesia. The purpose of this study was to determine the effects of active warming on the mother and newborn during elective cesarean section.

DESIGN

This research was carried out in an experimental design with a pretest-posttest randomized intervention and control group.

METHODS

The research was conducted with 34 women (17 intervention and 17 control), who gave birth by cesarean section. The study examined outcomes for both mother and newborn. Women in the intervention group were heated by both active (warmed with carbon fiber resistive underbody heaters during surgery) and passive heating (preoperative- socks, nonelectrified wool blankets, etc). Only passive heating methods were applied to the women in the control group (preoperative). Neonatal Activity - Pulse - Grimace - Appearence - Respiration (APGAR) score, body temperature, cortisol, and blood glucose levels in the intervention and control groups were evaluated, while body temperature and shivering conditions were evaluated in the mother.

FINDINGS

Body temperature and first minute APGAR score of the infants in the intervention and control groups after cesarean section were 36.88 ± 0.27, 36.52 ± 0.32 (P = .002); 7.00 ± 0.36, 7.47 ± 0.64 (P = .009), respectively. Cortisol and blood glucose levels in the intervention and control groups were 3.55 ± 1.09, 4.51 ± 0.70 (P = .010), 77.94 ± 7.07, 72.47 ± 10.24 (P > .05), respectively. The body temperatures of the women in the intervention and control groups at 15, 30, and 45 minutes were significantly different (P < .05), while they were similar (P > .05) at 60 minutes. Oxygen saturation measured at 30 minutes during the operation was 97.10 ± 1.41 in the intervention group and 95.20 ± 1.78 in the control group (P < .05).

CONCLUSIONS

Active warming before, during, and after cesarean section affected body temperature, pulse, respiration, blood pressure, and oxygen saturation of women, and while it increased the body temperature and APGAR score of newborns, it decreased cortisol level.

Maternal hypothermia during elective caesarean delivery: A prospective observational study

BACKGROUND

Patients undergoing caesarean delivery are at risk of developing unintended perioperative hypothermia, defined as a core temperature <36.0°C. Most previous studies of core temperature in caesarean delivery patients have not been conducted with accurate measurements for the complete perioperative period. Therefore, we conducted a prospective observational study to identify the incidence and duration of pre- and post-operative maternal hypothermia with a high accuracy continuous temperature monitoring system.

METHODS

Women ≥18 years old presenting for elective caesarean delivery under spinal anaesthesia were invited to participate in the study. The primary outcomes were the incidence and duration of perioperative maternal hypothermia (<36.0°C). Maternal core temperatures were measured with the non-invasive zero-heat-flux thermometer (Bair Hugger Temperature Monitoring System, 3M) throughout the perioperative course.

RESULTS

A total of 40 participants were recruited to the study. The incidence of perioperative hypothermia was 32.5%, with a duration of 77 ± 40 min (mean ± standard deviation). The hypothermic patients had similar core temperature as the normothermic patients at baseline preoperatively, but significantly lower temperature at operating room arrival and during the remaining study period. Forty percent of all patients reported thermal discomfort and felt cold on admission to post anaesthesia care unit, whereas 33% had shivering. Neither thermal discomfort nor shivering were associated with hypothermia.

CONCLUSION

In the present study almost a third of the women undergoing elective caesarean delivery developed perioperative hypothermia with a core temperature <36.0°C. The mean duration of maternal hypothermia was 77 min, lasting well into the postoperative period for many patients. These data should remind healthcare professionals of the importance of measuring core temperature in all phases of the perioperative setting and to consider optimal warming measures to avoid and treat hypothermia.

Incidence of Unintentional Intraoperative Hypothermia and Its Risk Factors in Oral and Maxillofacial Surgery: A Prospective Study

PURPOSE

Unintentional intraoperative hypothermia is a common complication in patients who undergo open surgery, increasing the risk of adverse outcomes. However, few studies have focused on intraoperative hypothermia during oral and maxillofacial surgery. Our study aimed to analyze the prevalence and risk factors of hypothermia in patients who underwent oral and maxillofacial surgery.

DESIGN

A prospective cohort study was conducted on 128 patients who underwent oral and maxillofacial surgery.

METHODS

This prospective study was conducted at West China Hospital of Stomatology between December 2020 and May 2021, and each patient was followed for at least 1-month postoperatively. Patients who underwent oral and maxillofacial surgery under general anesthesia, with at least 1-month follow-up were analyzed. The primary variable was intraoperative hypothermia, defined as core body temperature less than 36°C, measured using a tympanic thermometer during the surgery. We performed univariate and multivariate logistic regression analyses to identify the risk factors of unintentional intraoperative hypothermia.

FINDINGS

The mean age of the 128 patients was 31.0 ± 20.9 years, and there was a male predominance (53.1%), with male to female ratio of 1.13:1. Thirty-one patients (24.2%) developed hypothermia intraoperatively. Older age (OR = 1.068, 95% CI: 1.028-1.110, P = .001), lower weight (OR = 0.878, 95% CI: 0.807-0.955, P = .002), greater blood loss (OR = 1.003, 95% CI: 1.000-1.006, P = .034), and undergoing cancer surgery (OR = 0.210, 95% CI: 0.067-0.656, P = .007) were associated with intraoperative hypothermia.

CONCLUSIONS

Unintentional intraoperative hypothermia is common in patients who undergo surgery for oral cancer. Warming interventions to prevent intraoperative hypothermia for high-risk patients (older, lower weight, or more intraoperative bleeding) should be considered. Meanwhile, with careful nursing and rehabilitation instructions, intraoperative hypothermia does not lead to serious perioperative complications.

The effect of forced-air warming in the cesarean section on maternal hypothermia, shivering, and thermal comfort: A randomized controlled trial

This trial was carried out to investigate the effect of forced air warming in various body areas of women on hypothermia during cesarean delivery. The patients in the study groups (n = 76) were assigned to the full-body warming group, upper-extremity warming group, lower-extremity warming group, and control groups. The intervention groups received forced-air warming 30 min before the surgery and continued until 30 min after surgery. The incidence of hypothermia was significantly higher in the control group than in the other groups at the 60th minute of the operation (p < 0.01). The intervention and control groups showed significant differences in the frequency of shivering at the entrance to the PACU (p = 0.001). Thermal comfort scores have significant difference between the control group and all of the intervention groups (p<.001). It is said that the full-body forced-air warming technique prevents hypothermia, shivering, and thermal discomfort in women Cesarean Section (CS).

Combined Forced Air Warming and Warm Intravenous Fluid Strategy for Perioperative Hypothermia in Cesarean Delivery: A Systematic Review and Meta-Analysis

PURPOSE

Evaluate the effect of a combined forced-air warming (FAW) and warm intravenous fluid (IVF) modality on maternal and neonatal outcomes in cesarean delivery under neuraxial anesthesia.

DESIGN

Systematic Review and Meta-analysis.

METHODS

An extensive search was conducted using PubMed, Cochrane Library, MEDLINE, CINAHL, Google Scholar, and other grey literature. Only randomized controlled trials examining the combined modality on maternal temperatures were included. Risk ratio (RR), mean difference (MD), and standardized mean difference (SMD) were used to estimate outcomes with suitable effect models. Quality of evidence was assessed using the Risk of Bias and GRADE system.

FINDINGS

Nine trials involving 595 patients were included. Combined strategy showed a smaller change in maternal temperature from baseline by 0.42°C (MD, -0.42; 95% CI, -0.62 to -0.22; P < .0001), higher temperature on PACU arrival (MD, 0.46; 95% CI, 0.11-0.82; P = .01), 15 minutes (MD, 0.43; 95% CI, 0.19-0.67; P = .0004) and 30 minutes after surgery (MD, 0.38; 95% CI, 0.12-0.64; P = .005). Combined strategy also reduced the incidence of hypothermia (RR, 0.55; 95% CI, 0.31-0.95; P = .03), and shivering (RR, 0.40; 95% CI, 0.28-0.58; P < .00001) with improvement in maternal comfort score (SMD; 0.38; 95% CI, 0.08-0.69; P = .01). However, there were no differences in clinical indicators of adverse neonatal outcomes. Lack of participants blinding, and substantial heterogeneity were limitations of this review.

CONCLUSION

The use of combined FAW and warm IVF is an effective strategy in mitigating perioperative hypothermia in cesarean delivery under neuraxial anesthesia.

[The cesarean procedure: Guidelines for clinical practice from the French College of Obstetricians and Gynecologists]

OBJECTIVE

To identify procedures to reduce maternal morbidity during cesarean.

MATERIAL AND METHODS

The quality of evidence of the literature was assessed following the GRADE® method with questions formulated in the PICO format (Patients, Intervention, Comparison, Outcome) and outcomes defined a priori and classified according to their importance. An extensive bibliographic search was performed on PubMed, Cochrane and EMBASE databases. The quality of the evidence was assessed (high, moderate, low, very low) and a (i) strong or (ii) weak recommendations or (iii) no recommendation were formulated. The recommendations were reviewed in two rounds with external reviewers (Delphi survey) to select the consensus recommendations.

RESULTS

Of the 27 questions, there was agreement between the working group and the external reviewers on 26. The level of evidence of the literature was insufficient to provide a recommendation on 15 questions. Preventing hypothermia is recommended to increase maternal satisfaction and comfort (weak recommendation) and to reduce neonatal hypothermia (strong recommendation). The quality of the evidence of the literature did not allow to recommend the skin disinfectant to be used nor the relevance of a preoperative vaginal disinfection nor the choice between the use or nonuse of an indwelling bladder catheterization (if micturition takes place 1 hour before the cesarean section). The Misgav-Ladach technique or its analogues should be considered rather than the Pfannenstiel technique to reduce maternal morbidity (weak recommendation) bladder flap before uterine incision should not be performed routinely (weak recommendation), but a blunt (weak recommendation) and cephalad-caudad extension of uterine incision (weak recommendation) should be considered to reduce maternal morbidity. Antibiotic prophylaxis is recommended to reduce maternal infectious morbidity (strong recommendation) without recommendation on its type or the timing of administration (before incision or after cord clamping). The administration of carbetocin after cord clamping does not significantly decrease the incidence of blood loss>1000 ml, anemia, or blood transfusion compared with the administration of oxytocin. Thus, it is not recommended to use carbetocin rather than oxytocin in cesarean. It is recommended that systematic manual removal of the placenta not to be performed (weak recommendation). An antiemetic should be administered after cord clamping in women having a planned cesarean under locoregional anaesthesia to reduce intraoperative and postoperative nausea and vomiting (strong recommendation) with no recommendation regarding choice of use one or two antiemetics. The level of evidence of the literature was insufficient to provide any recommendation concerning single or double-layer closure of the uterine incision, or the uterine exteriorization. Closing the peritoneum (visceral or parietal) should not be considered (weak recommendation). The quality of the evidence of the literature was not sufficient to provide recommendation on systematic subcutaneous closure, including in obese or overweight patients, or the use of subcuticular suture in obese or overweight patients. The use of subcuticular suture in comparison with skin closure by staples was not considered as a recommendation due to the absence of a consensus in the external review rounds.

CONCLUSION

In case of cesarean, preventing hypothermia, administering antiemetic and antibiotic prophylaxis after cord clamping are the only strong recommendations. The Misgav-Ladach technique, the way of performing uterine incision (no systematic bladder flap, blunt cephalad-caudad extension), not performing routine manual removal of the placenta nor closure of the peritoneum are weak recommendations and may reduce maternal morbidity.

Effect of active and passive warming on preventing hypothermia and shivering during cesarean delivery: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Perioperative hypothermia and shivering commonly occur in pregnant women undergoing cesarean section. The warming method is usually used to prevent hypothermia and shivering. However, the effect of active warming (AW) prior to passive warming (PW) on the perioperative outcomes of pregnant women and their offspring remains controversial.

METHODS

This study aimed to investigate the effects of AW and PW on maternal and newborn perioperative outcomes during cesarean delivery. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, PubMed, Embase, Scopus, and the Cochrane Library were used to search for randomized controlled trials (RCTs) up to August 7, 2022. The Cochrane risk of bias assessment tool was used to assess articles selected for the systematic review. Continuous data were analyzed using weighted mean differences (WMDs) with 95% confidence intervals (CIs), and categorical data were analyzed by the random-effects model.

RESULTS

A total of 1241 participants from twelve RCTs were selected for the final meta-analysis. AW was associated with a lower risk of maternal hypothermia (RR: 0.77, 95% CI: 0.63-0.93, P = 0.007) and shivering (RR: 0.56, 95% CI: 0.37-0.85; P = 0.007). AW was associated with high maternal temperature (WMD: 0.27, 95%CI: 0.14 to 0.40, P < 0.001). No significant difference was observed between AW and PW in terms of hypothermia (RR: 0.60, 95% CI: 0.24-1.51, P = 0.278), temperature (WMD: 0.31, 95% CI: - 0.00 to 0.62; P = 0.050), and umbilical vein PH in newborns (WMD: -0.00; 95% CI: - 0.02 to 0.02, P = 0.710).

CONCLUSIONS

These findings suggested that AW can better prevent maternal hypothermia and shivering than PW. In contrast, no significant effect was observed in newborns. Overall, the quality of the included studies is high due to RCTs, low risk of bias, consistency, and precision. We identified the quality of the overall evidence from the survey to be GRADE I.

Evidence-Based Guideline on Prevention and Management of Shivering After Spinal Anesthesia in Resource-Limited Settings: Review Article

Background

Perioperative shivering is a common problem faced in anesthesia practice. Unless it is properly managed and prevented, it causes discomfort and devastating problems, especially in patients with cardiorespiratory problems. Surgery, anesthesia, exposure of skin in a cool operating theater, and administration of unwarmed fluids are some of the major causes for the development of shivering among surgical patients. Currently, a variety of non-pharmacological and pharmacological techniques are available to prevent and manage this problem. The available options to prevent and treat shivering include but are not limited to pre-warming the patient for 15 minutes before anesthesia administration, administration of low dose ketamine, dexamethasone, pethidine, clonidine, dexmedetomidine, tramadol, and magnesium sulfate.

Objective

To develop evidence-based recommendations for the prevention and management of shivering after spinal anesthesia in a resource-limited settings.

Methods

The kinds of literature are searched from Google Scholar, PubMed, Cochrane library, and HINARI databases to get access to current and update evidence on the prevention and management of shivering after spinal anesthesia. The keywords for the literature search were (shivering or prevention) AND (shivering or management) AND (anesthesia or shivering).

Conclusion

Pre-warming the patient with cotton, blanket, gown warming, and administering warm IV fluid 15 minutes before spinal anesthesia are possible non-pharmacologic options for the prevention of shivering. Furthermore, pharmacological medications like low dose ketamine, dexamethasone, magnesium sulfate, ad tramadol can be used as alternative options for the prevention and management strategies for shivering of different degrees in resource-limited areas.

Advances in the Prevention and Treatment of Neonatal Hypothermia in Early Birth

Neonates are vulnerable to hypothermia in the early postnatal period due to a low temperature environment, physiological function, and many other factors. In this article, the definition, occurrence status, related factors, hazards, and prevention strategies of neonatal hypothermia are reviewed. The interventions for hypothermia are mainly achieved through three processes, that is, intervention in the delivery room before and after birth, intervention on the way from the delivery room to the neonatal intensive care unit (NICU), and intervention after arrival at the NICU. Rewarming is the main intervention measure after the occurrence of hypothermia and slow rewarming is advocated, based on related studies of early neonatal cold injury syndrome and mild hypothermia treatment of hypoxic-ischemic encephalopathy. Rapid rewarming has been proposed in recent years but remains controversial. There are no detailed guidelines yet for rewarming for early neonatal hypothermia, and there is no precise definition of "rapid rewarming" and "slow rewarming" in terms of the rewarming rate.

Effectiveness of Combined Strategies for the Prevention of Hypothermia Measured by Noninvasive Zero-Heat Flux Thermometer During Cesarean Section

Background: Perioperative hypothermia (body temperature <36°C) is a common complication of anesthesia increasing the risk for maternal cardiovascular events and coagulative disorders, and can also influence neonatal health. The aim of our work was to evaluate the impact of combined warming strategies on maternal core temperature, measured with the SpotOn. We hypothesized that combined modalities of active warming prevent hypothermia in pregnant women undergoing cesarean delivery with spinal anesthesia. Methods: Seventy-eight pregnant women were randomly allocated into three study groups receiving warmed IV fluids and forced-air warming (AW), warmed IV fluids (WF), or no warming (NW). Noninvasive core temperature device (SpotOn) measured maternal core temperature intraoperatively and for 30 min after surgery. Maternal mean arterial pressure, incidence of shivering, thermal comfort and newborn's APGAR, axillary temperature, weight, and blood gas analysis were also recorded. Results: Incidence of hypothermia was of 0% in AW, 4% in WF, and 47% in NW. Core temperature in AW was constantly higher than WF and NW groups. Incidence of shivering in perioperative time was significantly lower in AW and WF groups compared with the NW group (p < 0.04). Thermal comfort was higher in both AW and WF groups compared with NW group (p = 0.02 and p = 0.008, respectively). There were no significant differences among groups for the other evaluated parameters. Conclusion: Combined modalities of active warming are effective in preventing perioperative hypothermia. The routine uses of combined AW are suggested in the setting of cesarean delivery.

Management of massive hemorrhage in pregnant women with placenta previa

Patients with placenta previa are at risk for intra- and postpartum massive blood loss as well as increased risk of placenta accreta, a type of abnormal placental implantation. This condition can lead to serious obstetric complications, including maternal mortality and morbidity. The risk factors for previa include prior cesarean section, multiparity, advanced maternal age, prior placenta previa history, prior uterine surgery, and smoking. The prevalence of previa parturients has increased due to the rising rates of cesarean section and advanced maternal age. For these reasons, we need to identify the risk factors for previa and identify adequate management strategies to respond to blood loss during surgery. This review evaluated the diagnosis of placenta previa and placenta accreta and assessed the risk factors for previa-associated bleeding prior to cesarean section. We then presented intraoperative anesthetic management and other interventions to control bleeding in patients with previa expected to experience massive hemorrhage and require transfusion.

The effect of combination of warm intravenous fluid infusion and forced air warming versus forced air warming alone on maternal temperature and shivering during cesarian delivery under spinal anesthesia

Objective

Administration of warm intravenous (IV) fluid infusion and use of forced air warmers is the most easy and physiologically viable method for maintaining normothermia during surgery and postsurgical periods This study was conducted to assess the effect of combination of active warming (AW) methods namely warm IV fluid infusion and forced air warming versus forced air warming only (WA) on maternal temperature during elective C-delivery under spinal anesthesia.

Materials and Methods

A total of 100 patients scheduled for elective c-section were grouped into those who received both warmed IV fluid infusion and forced air warmer (Combination of active warming WI= 50) and those who received only forced air warmer (WA = 50). Core body temperature and shivering incidence were recorded using a tympanic thermometer from prespinal till the end of surgery every 10 min and in postanesthesia care unit (PACU) at 0, 15, and 30 min.

Results

Core temperature showed statistically significant difference in 15, 35, 45, and 55 min between air warmer and warm infusion groups and in PACU at 0, 15, and 30 min, it was statistically significant (P = 0.000) among WI group (mean temperature = 36.79°C) when compared to WA group (mean temperature = 35.96°C). There was a lower incidence of shivering in WI compared to WA group, which is statistically significant.

Conclusion

Combination of warm Intravenous fluid infusion and Forced air warming is better than forced air warming alone. In maintaining near normal maternal core body temperature during elective cesarean section following spinal anesthesia. Combined warming method also reduces shivering incidence.

Improving intraoperative temperature management in elective repeat cesarean deliveries: a retrospective observational cohort study

Background

Inadvertent perioperative hypothermia (< 36 °C) occurs frequently during elective cesarean delivery and most institutions do employ perioperative active warming. The purpose of this retrospective observational cohort study was to determine if the addition of preoperative forced air warming in conjunction with intraoperative underbody forced air warming improved core temperature and reducing inadvertent perioperative hypothermia during elective repeat elective cesarean delivery with neuraxial anesthesia.

Methods

We evaluated the addition of perioperative active warming to standard passive warming methods (preheated intravenous/irrigation fluids and cotton blankets) in 120 parturients scheduled for repeat elective cesarean delivery (passive warming, n = 60 vs. active + passive warming, n = 60) in a retrospective observational cohort study. The primary outcomes of interest were core temperature at the end of the procedure and a decrease in inadvertent perioperative hypothermia (< 36 °C). Secondary outcomes were surgical site infections and adverse markers of neonatal outcome.

Results

The mean temperature at the end of surgery after instituting the active warming protocol was 36.0 ± 0.5 °C (mean ± SD, 95% CI 35.9–36.1) vs. 35.4 ± 0.5 °C (mean ± SD, 95% CI 35.3–35.5) compared to passive warming techniques (p <  0.001) and the incidence of inadvertent perioperative hypothermia at the end of the procedure was less in the active warming group - 68% versus 92% in the control group (p <  0.001). There was no difference in surgical site infections or neonatal outcomes.

Conclusions

Perioperative active warming in combination with passive warming techniques was associated with a higher maternal temperature and lower incidence of inadvertent perioperative hypothermia with no detectable differences in surgical site infections or indicators of adverse neonatal outcomes.

Effects of combined warmed preoperative forced-air and warmed perioperative intravenous fluids on maternal temperature during cesarean section: a prospective, randomized, controlled clinical trial

Background

Preventing the frequent perioperative hypothermia incidents that occur during elective caesarean deliveries would be beneficial. This trial aimed at evaluating the effect of preoperative forced-air warming alongside perioperative intravenous fluid warming in women undergoing cesarean sections under spinal anesthesia.

Methods

We randomly allocated 135 women undergoing elective cesarean deliveries to either the intervention group (preoperative forced-air and intravenous fluid warming, n = 69) or the control group (no active warming, n = 66). The primary outcome measure was the core temperature change between groups from baseline to the end of the surgical procedure. Secondary outcomes included thermal comfort scores, the incidences of shivering and hypothermia (< 36 °C), the core temperature on arrival at the post-anesthesia care unit, neonatal axillary temperature at birth, and Apgar scores.

Results

Two-way repeated measures ANOVA revealed significantly different core temperature changes (from the pre-spinal temperature to that at the end of the procedure) between groups (F = 13.022, P < 0.001). The thermal comfort scores were also higher in the intervention group than in the control group (F = 9.847, P = 0.002). The overall incidence of perioperative hypothermia was significantly lower in the intervention group than in the control group (20.6% vs. 51.6%, P < 0.0001).

Conclusions

Warming preoperative forced-air and perioperative intravenous fluids may prevent maternal hypothermia, reduce maternal shivering, and improve maternal thermal comfort for patients undergoing cesarean sections under spinal anesthesia.

Trial registration

The study was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR1800019117) on October26, 2018.

Effects of isothermic crystalloid coload on maternal hypotension and fetal outcomes during spinal anesthesia for cesarean section: A randomized controlled trial

OBJECTIVE

Spinal anesthesia induced hypotension (SAIH) is a common occurrence during spinal anesthesia for cesarean section resulting in perturbing effects on maternal and fetal outcomes. Previous studies conducted to attenuate SAIH focused on the timing of intravenous fluid infusion and demonstrated the superiority of coload strategy on traditional preload strategy but neither of them focused on the effect of the temperature of crystalloid infused on SAIH and fetal outcomes. The current study aimed to assess the effect of the temperature of the crystalloid infused with coload strategy on the incidence of SAIH and fetal outcomes.

MATERIALS AND METHODS

Seventy-six parturients were enrolled into the study and data of 60 parturients were analyzed. Patients were randomly assigned to receive crystalloid coload at room temperature (Group RT, n = 30) or warmed at 37 °C (Group W, n = 30). The incidence of hypotension, cumulative hypotension episodes, heart rate, core body temperature, ephedrine dose, and fetal outcomes were recorded.

RESULTS

There was no significant difference in the incidence of maternal hypotension, cumulative hypotension episodes, and ephedrine dose (p = 0,625, p = 0,871, p = 0,460 respectively). Umbilical arterial pH and fetal Apgar scores at first and fifth minutes were higher in Group W than in Group RT (p = 0.013, p = 0.006 and p = 0.045 respectively). One fetus in Group RT but none in Group W had umbilical arterial pH lower than seven. Fetal birth weight and rectal temperature measurements were comparable in both groups (p = 0.639 and p = 0.675 respectively). Demographic data, patient characteristics, and surgery data were comparable between groups.

CONCLUSIONS

Isothermic crystalloid coload strategy results in higher umbilical pH values and Apgar scores in parturients scheduled for cesarean section under spinal anesthesia.

Delivery room interventions to improve the stabilization of extremely-low-birth-weight infants

OBJECTIVE

To retrospectively verify whether the positioning of the umbilical venous catheter (UVC) in the delivery room (DR) and the early start of the preheated infusion of 10% glucose solution conditioned temperature and glycemia values of ELBW neonates in the first hours of life.

METHODS

Neonates (N = 137) were divided into two groups on the basis of timing of positioning of the UVC. In Group I the UVC was placed in DR, while in Group II after Neonatal Intensive Care Unit (NICU) admission. Data were assessed in different times: body temperature at neonatal admission to NICU (T₁); after 2 hours (T₂); then, every 2 hours until normothermia; glycemia value at NICU admission, every 1-2 hours in the first 12 hours, every 4 hours from 12 to 24 hours, and every 6-12 hours until normalization. Time slot childbirth was also detected since only in the morning shift there was a dedicated resuscitation team always present in DR, while during the afternoon and night it was available on-call. Preventive measures to limit heat dispersion were adopted in both Groups.

RESULTS

In Group I respect to Group II, both at T₁ and T₂: (a) the rate of normothermic neonates was higher and (b) the rate of neonates with moderate hypothermia was lower. The hourly temperature increase was similar between the groups and the time needed to reach normothermia was significantly lower in Group I than in Group II. Glycemic values at T₁ were lower in Group II. In Group II, after UVC positioning and glucose solution administration, the 42.2% of infants immediately brought glycemia back to normal, while the 57.8% needed specific treatment. The majority of newborns of Group I was born during the morning shift.

CONCLUSIONS

The early UVC placement by a dedicated interdisciplinary team is a relevant intervention to carry out during the "Golden minutes" to improve the ELBW stabilization soon after birth.

Evaluation of Warming Effectiveness on Physiological Indices of Patients Undergoing Laparoscopic Cholecystectomy Surgery: A Randomized Controlled Clinical Trial

PURPOSE

The present study aimed to evaluate the impact of warming on physiological indices of patients undergoing laparoscopic cholecystectomy.

DESIGN

The study was a three-group randomized controlled clinical trial.

METHODS

In the present study, 96 patients were assigned to three groups: forced-air warming system group; warmed intravenous fluid group; and control group. The intervention was performed immediately after the anesthesia induction. Physiological indices (core body temperature, blood pressure, and heart rate) were evaluated at 15-minute intervals, and postoperative shivering was also recorded.

FINDINGS

The mean systolic blood pressure and the mean heart rate were significantly different in each warming group before, during, and after surgery, but the three groups had no significant differences in terms of physiological indices at any time (P > .05). Postoperative shivering was not seen in any group.

CONCLUSIONS

Both interventions had similar effects on physiological indices. Therefore, the recommendation is to use the warming method according to patient's other conditions.

The effects of crystalloid warming on maternal body temperature and fetal outcomes: a randomized controlled trial

Background and objectives

Hypothermia occurs in about 60% of patients under anesthesia and is generally not managed properly during short lasting surgical procedures. Hypothermia is associated with adverse clinical outcomes. The current study is designed to assess the effects of crystalloid warming on maternal and fetal outcomes in patients undergoing elective cesarean section with spinal anesthesia.

Methods

In this prospective randomized controlled trial, sixty parturients scheduled for elective cesarean section with spinal anesthesia were randomly allocated to receive crystalloid at room temperature or warmed at 37 °C. Spinal anesthesia was performed at L3–L4 interspace with 10 mg of hyperbaric bupivacaine without adding opioids. Core temperature, shivering, and hemodynamic parameters were measured every minute until 10th minute and 5-min intervals until the end of operation. The primary outcome was maternal core temperature at the end of cesarean section.

Results

There was no difference for baseline tympanic temperature measurements but the difference was significant at the end of the operation (p = 0.004). Core temperature was 36.8 ± 0.5 °C at baseline and decreased to 36.3 ± 0.5 °C for isothermic warmed crystalloid group and baseline tympanic core temperature was 36.9 ± 0.4 °C and decreased to 35.8 ± 0.7 °C for room temperature group at the end of the operation. Shivering was observed in 43.3% in the control group. Hemodynamic parameter changes and demographic data were not significant between groups.

Conclusions

Isothermic warming crystalloid prevents the decrease in core temperature during cesarean section with spinal anesthesia in full-term parturients. Fetal Apgar scores at first and fifth minute are higher with isothermic warming.

Guidelines for intraoperative care in cesarean delivery: Enhanced Recovery After Surgery Society Recommendations (Part 2)

The Enhanced Recovery After Surgery Society guideline for intraoperative care in cesarean delivery will provide best practice, evidenced-based, recommendations for intraoperative care, with primarily a maternal focus. The "focused" pathway process for scheduled and unscheduled cesarean delivery for this Enhanced Recovery After Surgery cesarean delivery guideline will consider procedure from the decision to operate (starting with the 30-60 minutes before skin incision) through the surgery. The literature search (1966-2017) used Embase and PubMed to search medical subject headings including "cesarean section," "cesarean section," "cesarean section delivery," and all pre- and intraoperative Enhanced Recovery After Surgery items. Study selection allowed titles and abstracts to be screened by individual reviewers to identify potentially relevant articles. Metaanalyses, systematic reviews, randomized controlled studies, nonrandomized controlled studies, reviews, and case series were considered for each individual topic. Quality assessment and data analyses evaluated the quality of evidence and recommendations were evaluated according to the Grading of Recommendations, Assessment, Development and Evaluation system as used and described in previous Enhanced Recovery After Surgery Society guidelines. The Enhanced Recovery After Surgery cesarean delivery guideline/pathway has created a maternal focused pathway (for scheduled and unscheduled surgery starting from 30-60 minutes before skin incision to maternal discharge) with Enhanced Recovery After Surgery-directed preoperative elements, intraoperative elements, and postoperative elements. Specifics of the intraoperative care included the use of prophylactic antibiotics before the cesarean delivery, appropriate patient warming intraoperatively, blunt expansion of the transverse uterine hysterotomy, skin closure with subcuticular sutures, and delayed cord clamping. A number of specific elements of intraoperative care of women who undergo cesarean delivery are recommended based on the evidence. The Enhanced Recovery After Surgery Society guideline for intraoperative care in cesarean delivery will provide best practice, evidenced-based, recommendations for intraoperative care with primarily a maternal focus. When the cesarean delivery pathway (elements/processes) is studied, implemented, audited, evaluated, and optimized by maternity care teams, this will create an opportunity for the focused and optimized areas of care and recommendations to be further enhanced.

Clinical practice guideline. Unintentional perioperative hypothermia

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

[The effects of crystalloid warming on maternal body temperature and fetal outcomes: a randomized controlled trial]

BACKGROUND AND OBJECTIVES

Hypothermia occurs in about 60% of patients under anesthesia and is generally not managed properly during short lasting surgical procedures. Hypothermia is associated with adverse clinical outcomes. The current study is designed to assess the effects of crystalloid warming on maternal and fetal outcomes in patients undergoing elective cesarean section with spinal anesthesia.

METHODS

In this prospective randomized controlled trial, sixty parturients scheduled for elective cesarean section with spinal anesthesia were randomly allocated to receive crystalloid at room temperature or warmed at 37°C. Spinal anesthesia was performed at L3-L4 interspace with 10mg of hyperbaric bupivacaine without adding opioids. Core temperature, shivering, and hemodynamic parameters were measured every minute until 10th minute and 5-min intervals until the end of operation. The primary outcome was maternal core temperature at the end of cesarean section.

RESULTS

There was no difference for baseline tympanic temperature measurements but the difference was significant at the end of the operation (p=0.004). Core temperature was 36.8±0.5°C at baseline and decreased to 36.3±0.5°C for isothermic warmed crystalloid group and baseline tympanic core temperature was 36.9±0.4°C and decreased to 35.8±0.7°C for room temperature group at the end of the operation. Shivering was observed in 43.3% in the control group. Hemodynamic parameter changes and demographic data were not significant between groups.

CONCLUSIONS

Isothermic warming crystalloid prevents the decrease in core temperature during cesarean section with spinal anesthesia in full-term parturients. Fetal Apgar scores at first and fifth minute are higher with isothermic warming.

Interventions to prevent hypothermia at birth in preterm and/or low birth weight infants

BACKGROUND

Newborn admission temperature is a strong predictor of outcomes across all gestations. Hypothermia immediately after birth remains a worldwide issue and, if prolonged, is associated with harm. Keeping preterm infants warm is difficult even when recommended routine thermal care guidelines are followed in the delivery room.

OBJECTIVES

To assess the efficacy and safety of interventions designed for prevention of hypothermia in preterm and/or low birth weight infants applied within 10 minutes after birth in the delivery room, compared with routine thermal care or any other single/combination of intervention(s) also designed for prevention of hypothermia in preterm and/or low birth weight infants applied within 10 minutes after birth in the delivery room.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 5), MEDLINE via PubMed (1966 to 30 June 2016), Embase (1980 to 30 June 2016), and CINAHL (1982 to 30 June 2016). We also searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Trials using randomised or quasi-randomised allocations to test interventions designed to prevent hypothermia (apart from 'routine' thermal care) applied within 10 minutes after birth in the delivery room for infants at < 37 weeks' gestation and/or birth weight ≤ 2500 grams.

DATA COLLECTION AND ANALYSIS

We used Cochrane Neonatal methods when performing data collection and analysis.

MAIN RESULTS

Twenty-five studies across 15 comparison groups met the inclusion criteria, categorised as: barriers to heat loss (18 studies); external heat sources (three studies); and combinations of interventions (four studies).Barriers to heat loss Plastic wrap or bag versus routine carePlastic wraps improved core body temperature on admission to the neonatal intensive care unit (NICU) or up to two hours after birth (mean difference (MD) 0.58°C, 95% confidence interval (CI) 0.50 to 0.66; 13 studies; 1633 infants), and fewer infants had hypothermia on admission to the NICU or up to two hours after birth (typical risk ratio (RR) 0.67, 95% CI 0.62 to 0.72; typical risk reduction (RD) -0.25, 95% CI -0.29 to -0.20; number needed to treat for an additional beneficial outcome (NNTB) 4, 95% CI 4 to 5; 10 studies; 1417 infants). Risk of hyperthermia on admission to the NICU or up to two hours after birth was increased in infants in the wrapped group (typical RR 3.91, 95% CI 2.05 to 7.44; typical RD 0.04, 95% CI 0.02 to 0.06; number needed to treat for an additional harmful outcome (NNTH) 25, 95% CI 17 to 50; 12 studies; 1523 infants), but overall, fewer infants receiving plastic wrap were outside the normothermic range (typical RR 0.75, 95% CI 0.69 to 0.81; typical RD -0.20, 95% CI -0.26 to -0.15; NNTH 5, 95% CI 4 to 7; five studies; 1048 infants).Evidence was insufficient to suggest that plastic wraps or bags significantly reduce risk of death during hospital stay or other major morbidities, with the exception of reducing risk of pulmonary haemorrhage.Evidence of practices regarding permutations on this general approach is still emerging and has been based on the findings of only one or two small studies.External heat sourcesEvidence is emerging on the efficacy of external heat sources, including skin-to-skin care (SSC) versus routine care (one study; 31 infants) and thermal mattress versus routine care (two studies; 126 infants).SSC was shown to be effective in reducing risk of hypothermia when compared with conventional incubator care for infants with birth weight ≥ 1200 and ≤ 2199 grams (RR 0.09, 95% CI 0.01 to 0.64; RD -0.56, 95% CI -0.84 to -0.27; NNTB 2, 95% CI 1 to 4). Thermal (transwarmer) mattress significantly kept infants ≤ 1500 grams warmer (MD 0.65°C, 95% CI 0.36 to 0.94) and reduced the incidence of hypothermia on admission to the NICU, with no significant difference in hyperthermia risk.Combinations of interventionsTwo studies (77 infants) compared thermal mattresses versus plastic wraps or bags for infants at ≤ 28 weeks' gestation. Investigators reported no significant differences in core body temperature nor in the incidence of hypothermia, hyperthermia, or core body temperature outside the normothermic range on admission to the NICU.Two additional studies (119 infants) compared plastic bags and thermal mattresses versus plastic bags alone for infants at < 31 weeks' gestation. Meta-analysis of these two studies showed improvement in core body temperature on admission to the NICU or up to two hours after birth, but an increase in hyperthermia. Data show no significant difference in the risk of having a core body temperature outside the normothermic range on admission to the NICU nor in the risk of other reported morbidities.

AUTHORS' CONCLUSIONS

Evidence of moderate quality shows that use of plastic wraps or bags compared with routine care led to higher temperatures on admission to NICUs with less hypothermia, particularly for extremely preterm infants. Thermal mattresses and SSC also reduced hypothermia risk when compared with routine care, but findings are based on two or fewer small studies. Caution must be taken to avoid iatrogenic hyperthermia, particularly when multiple interventions are used simultaneously. Limited evidence suggests benefit and no evidence of harm for most short-term morbidity outcomes known to be associated with hypothermia, including major brain injury, bronchopulmonary dysplasia, retinopathy of prematurity, necrotising enterocolitis, and nosocomial infection. Many observational studies have shown increased mortality among preterm hypothermic infants compared with those who maintain normothermia, yet evidence is insufficient to suggest that these interventions reduce risk of in-hospital mortality across all comparison groups. Hypothermia may be a marker for illness and poorer outcomes by association rather than by causality. Limitations of this review include small numbers of identified studies; small sample sizes; and variations in methods and definitions used for hypothermia, hyperthermia, normothermia, routine care, and morbidity, along with lack of power to detect effects on morbidity and mortality across most comparison groups. Future studies should: be adequately powered to detect rarer outcomes; apply standardised morbidity definitions; focus on longer-term outcomes, particularly neurodevelopmental outcomes.

Preoperative Warming Versus no Preoperative Warming for Maintenance of Normothermia in Women Receiving Intrathecal Morphine for Cesarean Delivery: A Single-Blinded, Randomized Controlled Trial

BACKGROUND

Rates of hypothermia for women undergoing spinal anesthesia for cesarean delivery are high and prevention is desirable. This trial compared the effectiveness of preoperative warming versus usual care among women receiving intrathecal morphine, which is thought to exacerbate perioperative heat loss.

METHODS

A prospective, single-blinded, randomized controlled trial compared 20 minutes of forced air warming (plus intravenous fluid warming) versus no active preoperative warming (plus intravenous fluid warming) in 50 healthy American Society of Anesthesiologists graded II women receiving intrathecal morphine as part of spinal anesthesia for elective cesarean delivery. The primary outcome of maternal temperature change was assessed via aural canal and bladder temperature measurements at regular intervals. Secondary outcomes included maternal thermal comfort, shivering, mean arterial pressure, agreement between aural temperature, and neonatal outcomes (axillary temperature at birth, Apgar scores, breastfeeding, and skin-to-skin contact). The intention-to-treat population was analyzed with descriptive statistics, general linear model analysis, linear mixed-model analysis, χ test of independence, Mann-Whitney, and Bland-Altman analysis. Full ethical approval was obtained, and the study was registered on the Australia and New Zealand Clinical Trials Registry (Trial No: 367160, registered at http://www.ANZCTR.org.au/).

RESULTS

Intention-to-treat analysis (n = 50) revealed no significant difference in aural temperature change from baseline to the end of the procedure between groups: F (1, 47) = 1.2, P = .28. There were no other statistically significant differences between groups in any of the secondary outcomes.

CONCLUSIONS

A short period of preoperative warming is not effective in preventing intraoperative temperature decline for women receiving intrathecal morphine. A combination of preoperative and intraoperative warming modalities may be required for this population.

A Clinical Trial of the Effect of Warm Intravenous Fluids on Core Temperature and Shivering in Patients Undergoing Abdominal Surgery

PURPOSE

This study was conducted to investigate the effect of warm intravenous fluids on shivering and core temperature of patients undergoing abdominal surgery.

DESIGN

This study was a two-group clinical-control trial.

METHODS

Ringer's solution at normal room temperature and serum at 38°C were infused in the control and intervention groups, respectively. Shivering, core temperature, SpO₂, and vital signs were measured at admission to the operating room and postanesthesia care unit (PACU) and 30 minutes after the admission to the PACU.

FINDINGS

There was a significant difference between the two groups in terms of shivering, core temperature, and pulse rate at the time of admission to the PACU and 30 minutes after.

CONCLUSIONS

Ringer's solution at 38°C instead of room temperature can be used to reduce the incidence of postanesthetic hypothermia and shivering in patients undergoing abdominal surgery. Using this method in addition to other nursing care is recommended preoperatively.

Predictive factors of maternal hypothermia during Cesarean delivery: a prospective cohort study

PURPOSE

Although perioperative hypothermia may increase maternal morbidity, active warming is infrequently performed to maintain normothermia during Cesarean delivery (CD). The aim of this prospective observational study was to determine the factors associated with maternal hypothermia in this setting.

METHODS

Women scheduled for elective or emergency CD were consecutively included in this study from November 2014 to October 2015. Maternal temperature was measured using an infrared tympanic thermometer on the patient's arrival in the operating room, at skin incision, and at the end of skin suture. Maternal hypothermia was defined by tympanic temperature < 36°C at the end of skin suture. Univariate analysis was performed, followed by multivariate logistic regression analysis, in order to determine the factors associated with maternal hypothermia at the end of the surgery.

RESULTS

Three hundred fifty-nine women were included and analyzed during this study. The incidence of hypothermia was 23% (95% confidence interval, 18 to 27) among the total population included. According to multivariate analysis, obesity, oxytocin augmentation of labour, and use of active forced-air warming were associated with a decreased risk of maternal hypothermia, while maternal temperature < 37.1°C on arrival in the operating room, maternal temperature < 36.6°C at skin incision, and an infused volume of fluids > 650 mL were significantly associated with maternal hypothermia. Both goodness of fit and predictive value of multivariate analysis were high.

CONCLUSION

Several predictive factors for maternal hypothermia during CD were identified. These factors should be taken into account to help prevent maternal hypothermia during CD.

Prevalence, associated factors and treatment of post spinal shivering in a Sub-Saharan tertiary hospital: a prospective observational study

Background

Surgery and anaesthesia cause shivering due to thermal dysregulation as a compensatory mechanism and is worsened by vasodilatation from spinal anaesthesia that redistributes core body heat. Due to paucity of data Mulago Hospital’s post spinal shivering burden is unknown yet it causes discomfort and morbidity.

Methods

Ethical approval was obtained to perform the study among consenting mothers due for elective caesarean section from March to May 2011. We recruited ASA class I & II parturients and excluded non-consenting or spinal contra-indication patients. A standard spinal anaesthetic of 2mls of 0.5 % bupivacaine was given, intraoperative vitals were recorded every 5 min and we monitored for perioperative shivering till PACU discharge.

Results

We recruited 270 patients with majority being emergency caesarean deliveries (90.74 %), mainly due to failed progress from cephalopelvic disproportion. We noted 8.15 % shivering occuring mostly at 20 min, with hypotension plus hypothermia as associated factors. Intravenous pethidine (Meperidine) 25 mg effectively treated shivering and we had drowsiness, nausea and vomiting as PACU side effects that resolved on discharge to the ward.

Conclusion

Post spinal shivering had a prevalence of 8.15 %, commonly occurred at 20 min postoperatively with hypotension plus hypothermia as main associated factors and intravenous Pethidine controlled it.

The Effect of patient warming during Caesarean delivery on maternal and neonatal outcomes: a meta-analysis

BACKGROUND

Perioperative warming is recommended for surgery under anaesthesia, however its role during Caesarean delivery remains unclear. This meta-analysis aimed to determine the efficacy of active warming on outcomes after elective Caesarean delivery.

METHODS

We searched databases for randomized controlled trials utilizing forced air warming or warmed fluid within 30 min of neuraxial anaesthesia placement. Primary outcome was maximum temperature change. Secondary outcomes included maternal (end of surgery temperature, shivering, thermal comfort, hypothermia) and neonatal (temperature, umbilical cord pH and Apgar scores) outcomes. Standardized mean difference/mean difference/risk ratio (SMD/MD/RR) and 95% confidence interval (CI) were calculated using random effects modelling (CMA, version 2, 2005).

RESULTS

13 studies met our criteria and 789 patients (416 warmed and 373 controls) were analysed for the primary outcome. Warming reduced temperature change (SMD -1.27°C [-1.86, -0.69]; P=0.00002); resulted in higher end of surgery temperatures (MD 0.43 °C [0.27, 0.59]; P<0.00001); was associated with less shivering (RR 0.58 [0.43, 0.79]; P=0.0004); improved thermal comfort (SMD 0.90 [0.36, 1.45]; P=0.001), and decreased hypothermia (RR 0.66 [0.50, 0.87]; P=0.003). Umbilical artery pH was higher in the warmed group (MD 0.02 [0, 0.05]; P=0.04). Egger's test (P=0.001) and contour-enhanced funnel plot suggest a risk of publication bias for the primary outcome of temperature change.

CONCLUSIONS

Active warming for elective Caesarean delivery decreases perioperative temperature reduction and the incidence of hypothermia and shivering. These findings suggest that forced air warming or warmed fluid should be used for elective Caesarean delivery.

Perioperative warming with a thermal gown prevents maternal temperature loss during elective cesarean section. A randomized clinical trial

BACKGROUND AND OBJECTIVES

Decrease in body temperature is common during general and regional anesthesia. Forced-air warming intraoperative during cesarean section under spinal anesthesia seems not able to prevent it. The hypothesis considers that active warming before the intraoperative period avoids temperature loss during cesarean.

METHODS

Forty healthy pregnant patients undergoing elective cesarean section with spinal anesthesia received active warming from a thermal gown in the preoperative care unit 30min before spinal anesthesia and during surgery (Go, n=20), or no active warming at any time (Ct, n=20). After induction of spinal anesthesia, the thermal gown was replaced over the chest and upper limbs and maintained throughout study. Room temperature, hemoglobin saturation, heart rate, arterial pressure, and tympanic body temperature were registered 30min before (baseline) spinal anesthesia, right after it (time zero) and every 15min thereafter.

RESULTS

There was no difference for temperature at baseline, but they were significant throughout the study (p<0.0001; repeated measure ANCOVA). Tympanic temperature baseline was 36.6±0.3°C, measured 36.5±0.3°C at time zero and reached 36.1±0.2°C for gown group, while control group had baseline temperature of 36.4±0.4°C, measured 36.3±0.3°C at time zero and reached 35.4±0.4°C (F=32.53; 95% CI 0.45-0.86; p<0.001). Hemodynamics did not differ throughout the study for both groups of patients.

CONCLUSION

Active warming 30min before spinal anesthesia and during surgery prevented a fall in body temperature in full-term pregnant women during elective cesarean delivery.

Warming of intravenous and irrigation fluids for preventing inadvertent perioperative hypothermia

BACKGROUND

Inadvertent perioperative hypothermia (a drop in core temperature to below 36°C) occurs because of interference with normal temperature regulation by anaesthetic drugs, exposure of skin for prolonged periods and receipt of large volumes of intravenous and irrigation fluids. If the temperature of these fluids is below core body temperature, they can cause significant heat loss. Warming intravenous and irrigation fluids to core body temperature or above might prevent some of this heat loss and subsequent hypothermia.

OBJECTIVES

To estimate the effectiveness of preoperative or intraoperative warming, or both, of intravenous and irrigation fluids in preventing perioperative hypothermia and its complications during surgery in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 2), MEDLINE Ovid SP (1956 to 4 February 2014), EMBASE Ovid SP (1982 to 4 February 2014), the Institute for Scientific Information (ISI) Web of Science (1950 to 4 February 2014), Cumulative Index to Nursing and Allied Health Literature (CINAHL) EBSCOhost (1980 to 4 February 2014) and reference lists of identified articles. We also searched the Current Controlled Trials website and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomized controlled trials or quasi-randomized controlled trials comparing fluid warming methods versus standard care or versus other warming methods used to maintain normothermia.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from eligible trials and settled disputes with a third review author. We contacted study authors to ask for additional details when needed. We collected data on adverse events only if they were reported in the trials.

MAIN RESULTS

We included in this review 24 studies with a total of 1250 participants. The trials included various numbers and types of participants. Investigators used a range of methods to warm fluids to temperatures between 37°C and 41°C. We found that evidence was of moderate quality because descriptions of trial design were often unclear, resulting in high or unclear risk of bias due to inappropriate or unclear randomization and blinding procedures. These factors may have influenced results in some way. Our protocol specified the risk of hypothermia as the primary outcome; as no trials reported this, we decided to include data related to mean core temperature. The only secondary outcome reported in the trials that provided useable data was shivering. Evidence was unclear regarding the effects of fluid warming on bleeding. No data were reported on our other specified outcomes of cardiovascular complications, infection, pressure ulcers, bleeding, mortality, length of stay, unplanned intensive care admission and adverse events.Researchers found that warmed intravenous fluids kept the core temperature of study participants about half a degree warmer than that of participants given room temperature intravenous fluids at 30, 60, 90 and 120 minutes, and at the end of surgery. Warmed intravenous fluids also further reduced the risk of shivering compared with room temperature intravenous fluidsInvestigators reported no statistically significant differences in core body temperature or shivering between individuals given warmed and room temperature irrigation fluids.

AUTHORS' CONCLUSIONS

Warm intravenous fluids appear to keep patients warmer during surgery than room temperature fluids. It is unclear whether the actual differences in temperature are clinically meaningful, or if other benefits or harms are associated with the use of warmed fluids. It is also unclear if using fluid warming in addition to other warming methods confers any benefit, as a ceiling effect is likely when multiple methods of warming are used.

A systematic review of the effectiveness of warming interventions for women undergoing cesarean section

BACKGROUND

Women undergoing cesarean section are vulnerable to adverse effects associated with inadvertent perioperative hypothermia, but there has been a lack of synthesized evidence for temperature management in this population. This systematic review aimed to synthesize the best available evidence in relation to preventing hypothermia in mothers undergoing cesarean section surgery.

METHODS

Randomized controlled trials meeting the inclusion criteria (adult patients of any ethnic background, with or without comorbidities, undergoing any mode of anesthesia for any type of cesarean section) were eligible for consideration. Active or passive warming interventions versus usual care or placebo, aiming to limit or manage core heat loss in women undergoing cesarean section were considered. The primary outcome was maternal core temperature. A comprehensive search with no language restrictions was undertaken of multiple databases from their inception until May 2012. Two independent reviewers using the standardized critical appraisal instrument for randomized controlled trials from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instruments (JBI-MASTARI) assessed retrieved papers for methodological quality and conducted data collection. Where possible, results were combined in a fixed effects meta-analysis using the Cochrane Collaboration Review Manager software. Due to heterogeneity for one outcome, random effects meta-analysis was also used.

RESULTS

A combined total of 719 participants from 12 studies were included. Intravenous fluid warming was found to be effective at maintaining maternal temperature and preventing shivering. Warming devices, including forced air warming and under-body carbon polymer mattresses, were effective at preventing hypothermia. However, effectiveness increased if the devices were applied preoperatively. Preoperative warming devices reduced shivering and improved neonatal temperatures at birth. Intravenous fluid warming did not improve neonatal temperature, and the effectiveness of warming interventions on umbilical pH remains unclear.

LINKING EVIDENCE TO ACTION

Intravenous fluid warming by any method improves maternal temperature and reduces shivering during and after cesarean section, as does preoperative body warming. Preoperative warming strategies should be utilized where possible. Preoperative or intraoperative warmed IV fluids should be standard practice. Warming strategies are less effective when intrathecal opioids are administered. Further research is needed to investigate interventions in emergency cesarean section surgery. Larger scale studies using standardized, clinically meaningful temperature measurement time points are required.

Peri-operative warming devices: performance and clinical application

Since the adverse consequences of accidental peri-operative hypothermia have been recognised, there has been a rapid expansion in the development of new warming equipment designed to prevent it. This is a review of peri-operative warming devices and a critique of the evidence assessing their performance. Forced-air warming is a common and extensively tested warming modality that outperforms passive insulation and water mattresses, and is at least as effective as resistive heating. More recently developed devices include circulating water garments, which have shown promising results due to their ability to cover large surface areas, and negative pressure devices aimed at improving subcutaneous perfusion for warming. We also discuss the challenge of fluid warming, looking particularly at how devices' performance varies according to flow rate. Our ultimate aim is to provide a guide through the bewildering array of devices on the market so that clinicians can make informed and accurate choices for their particular hospital environment.