The effects of forced air warming system on the hemodynamic status, pain intensity, tremors, nausea and vomiting in candidates of emergency laparotomy patients: a double-blind randomized clinical trial

During emergency laparotomy surgeries, a wide incision is usually created in the abdomen causing the exposure of visceral organs to cold temperatures in the operation room. Other factors such as excessive stress, intra-operation blood transfusion, and prolonged anesthesia increase the risk of hypothermia in these patients. In this study, we studied the effects of forced air warming systems on the hemodynamic status, pain intensity, tremors, nausea and vomiting in emergency laparotomy patients. 

In the present double-blinded clinical trial, 80 candidates for emergency laparotomy were randomized into two groups: intervention (patients receiving forced air warming during anesthesia) and control (patients without an active warming system). Patients’ hemodynamic status (during anesthesia and at post anesthesia care unit (PACU), pain intensity, opioids received, tremors, nausea, vomiting, and antiemetics administration were compared between the two groups. 

The amounts of opioids (P=0.041) and relaxants (P=0.039) received by the patients were significantly lower in the intervention group than in the control group. The hemodynamic status was more stable in the patients of the intervention group than those in the control group at all times measured. Pain intensity (per minute) at the PACU was significantly higher in the control group than in the intervention group (P=0.041). Among the patients admitted to the PACU, participants with no tremors (P=0.005) or nausea (P=0.005) were significantly higher in the intervention group than in the control group. Also, in the recovery unit, patients in the intervention group received significantly lower amounts of opioids (i.e., mg of pethidine, P=0.036) and antiemetics (P=0.011) compared to the control group. 

The use of a forced air warming system in the operation room stabilizes the hemodynamic status and reduces the pain intensity, tremors, nausea and vomiting in emergency laparotomy patients. As a non-pharmacological strategy, this method was observed to have satisfactory safety.