The effect of intraoperative hypothermia upon blood transfusion needs and length of stay among gastrointestinal system cancer surgery

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

BACKGROUND

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

AIM

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

METHODS

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

FINDINGS

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

CONCLUSIONS

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

A retrospective evaluation of the risk of bias in perioperative temperature metrics

The prevention and treatment of hypothermia is an important part of routine anesthesia care. Avoidance of perioperative hypothermia was introduced as a quality metric in 2010. We sought to assess the integrity of the perioperative hypothermia metric in routine care at a single large center. Perioperative temperatures from all anesthetics of at least 60 min duration between January 2012 and 2017 were eligible for inclusion in analysis. Temperatures were displayed graphically, assessed for normality, and analyzed using paired comparisons. Automatically-recorded temperatures were obtained from several monitoring sites. Provider-entered temperatures were non-normally distributed, exhibiting peaks at temperatures at multiples of 0.5 °C. Automatically-acquired temperatures, on the other hand, were more normally distributed, demonstrating smoother curves without peaks at multiples of 0.5 °C. Automatically-acquired median temperature was highest, 36.8 °C (SD = 0.8 °C), followed by the three manually acquired temperatures (nurse-documented postoperative temperature, 36.5 °C [SD = 0.6 °C]; intraoperative manual temperature, 36.5 °C [SD = 0.6 °C]; provider-documented postoperative temperature, 36.1 °C [SD = 0.6 °C]). Provider-entered temperatures exhibit values that are unlikely to represent a normal probability distribution around a central physiologic value. Manually-entered perioperative temperatures appear to cluster around salient anchoring values, either deliberately, or as an unintended result driven by cognitive bias. Automatically-acquired temperatures may be superior for quality metric purposes.

A Comparison of the Effects of Lung Protective Ventilation and Conventional Ventilation on Thermoregulation During Anaesthesia

Objective

During prolonged surgery, hypothermia is an unwanted condition that frequently develops and increases complication rates. It has been shown that positive end-expiratory pressure (PEEP) during mechanical ventilation reduces hypothermia development by providing earlier peripheral vasoconstriction. In the present study, an investigation was made of the effect of two different ventilation models on perioperative hypothermia development.

Methods

A total of 40 patients undergoing elective lumbar disc surgery were randomised to either the conventional group (Group C, n=20, tidal volume=10 mL kg^-1, PEEP=0 cm H₂O) or the lung protective ventilation group (Group P, n=20, tidal volume=6 mL kg^-1, PEEP=5 cm H₂O). Demographic data on gender, age, weight, height, preoperative-postoperative temperatures and haemodynamic values were recorded. The point where the forearm to fingertip skin temperature difference reached 0°C was determined as the peripheral vasoconstriction development. At this point, the core temperature was recorded as the thermoregulatory vasoconstriction threshold.

Results

Demographic characteristics of the patients and haemodynamic variables were similar between the groups. Preoperative and postoperative temperature gradients were not significantly different between the two groups (p=0.827). There was also no significant difference between the two groups in respect of the vasoconstriction threshold of the patients (p=0.432).

Conclusion

The study results showed that lung protective ventilation has no advantage in preserving the perioperative core temperature compared to conventional ventilation.