Hypothermia prevention and treatment

Comparative study between intrathecal dexmedetomidine and intrathecal magnesium sulfate for the prevention of post-spinal anaesthesia shivering in uroscopic surgery; (RCT)

Background

Hypothermia and shivering are common complications after spinal anaesthesia, especially after uroscopic procedures in which large amounts of cold intraluminal irrigation fluids are used. Magnesium sulfate and dexmedetomidine are the most effective adjuvants with the least side effects. The aim of this study was to compare the effects of intrathecal dexmedetomidine versus intrathecal magnesium sulfate on the prevention of post-spinal anaesthesia shivering.

Methods

This prospective randomized, double-blinded controlled study included 105 patients who were scheduled for uroscopic surgery at the Kasr El-Aini Hospital. The patients were randomly allocated into three groups. Group C (n = 35) received 2.5 ml of hyperbaric bupivacaine 0.5% (12.5 mg) + 0.5 ml of normal saline, Group M (n = 35) received 2.5 ml of hyperbaric bupivacaine 0.5% (12.5 mg) + 25 mg of magnesium sulfate in 0.5 ml saline, and Group D (n = 35) received 2.5 ml of hyperbaric bupivacaine 0.5% (12.5 mg) + 5 μg of dexmedetomidine in 0.5 ml saline. The primary outcomes were the incidence and intensity of shivering. The secondary outcomes were the incidence of hypothermia, sedation, the use of meperidine to control shivering and complications.

Results

Group C had significantly higher proportions of patients who developed shivering (21), developed grade IV shivering (20) and required meperidine (21) to treat shivering than group M (8,5,5) and group D (5,3,6), which were comparable to each other.

The time between block administration and meperidine administration was similar among the three groups. Hypothermia did not occur in any of the patients.

The three groups were comparable regarding the occurrence of nausea, vomiting, bradycardia and hypotension. All the patients in group C, 32 patients in group M and 33 patients in group D had a sedation score of 2. Three patients in group M and 2 patients in group D had a sedation score of 3.

Conclusions

Intrathecal injections of both dexmedetomidine and magnesium sulfate were effective in reducing the incidence of post-spinal anaesthesia shivering. Therefore, we encourage the use of magnesium sulfate, as it is more physiologically available, more readily available in most operating theatres and much less expensive than dexmedetomidine.

Trial registration

Clinical trial registration ID: Pan African Clinical Trial Registry (PACTR) Trial Number PACTR201801003001727; January 2018, “retrospectively registered”.

Comparative study between Dexmedetomidine and Ondansteron for prevention of post spinal shivering. A randomized controlled trial

Background

Regional anesthesia could affect the homeostatic system functions resulting frequently in perioperative hypothermia and consequently shivering. The objective of this trial was to evaluate the efficacy of dexmedetomidine and ondansetron to reduce the incidence and severity of shivering after intrathecal blocks.

Methods

This randomized placebo-controlled trial included 120 patients allocated equally in three groups. All patients were anesthetized by standard intrathecal blocks for surgical procedure at lower half of the body and received one of the study drugs intravenously (IV) according to the group assignments. Group S patients (placebo) were administered saline, Group O (ondansetron) were given 8 mg ondansetron, and Group D (dexmedetomidine) were given 1 μg/kg of dexmedetomidine. Shivering incidence and scores, sedation scores, core body temperature, hemodynamic variables, and incidence of complications (nausea, vomiting, hypotension, bradycardia, over-sedation, and desaturation) were recorded.

Results

The incidence and 95% confidence interval (95% CI) of shivering in group S 57.5% (42.18–72.82%) was significantly higher than that of both group O 17.5% (5.73–29.27%), P < 0.001 and group D 27.5% (13.66–41.34%), P = 0.012. However, the difference in the incidence of shivering between group O and group D was comparable, P = 0.425. The sedation scores were significantly higher in group D than those of both group S and group O, P < 0.001. Sedation scores between group S and group O were comparable, P = 0.19. Incidences of adverse effects were comparable between the three groups.

Conclusion

Prophylactic administrations of dexmedetomidine or ondansetron efficiently decrease the incidence and severity of shivering after spinal anesthesia as compared to placebo without significant difference between their efficacies when compared to each other.

Trial registration

Pan African Clinical Trial Registry (PACTR) under trial number (PACTR201710002706318). 18-10-2017. ‘retrospectively registered’.

Effects of Fentanyl and Morphine on Shivering During Spinal Anesthesia in Patients Undergoing Endovenous Ablation of Varicose Veins

Background

We sought to investigate the effect of morphine and fentanyl on shivering when used adjunctively with bupivacaine during spinal anesthesia in patients undergoing varicose vein surgery on an outpatient basis.

Material/Methods

The study included a total of 90 patients, aged 25–45 years, ASA I–II, scheduled to undergo endovenous laser ablation under spinal anesthesia for lower extremity venous insufficiency/varicose vein disease. Patients were randomly allocated into 3 groups: Group M (morphine group) received 5 mg 0.5% hyperbaric bupivacaine + 0.1 mg morphine, Group F (fentanyl group) received 5 mg 0.5% hyperbaric bupivacaine + 25 μg fentanyl, and Group C (control group) received 5 mg 0.5% hyperbaric bupivacaine + physiologic saline. The level of sensory blockade was assessed with pin-prick test and the level of motor blockade was assessed with Bromage scale at 5-min intervals. Shivering grade and time to first postoperative analgesic requirement was recorded.

Results

Level and time of sensory block showed a slight but insignificant increase in the Morphine Group and Fentanyl Group. Time of postoperative analgesic requirement was significantly longer in patients who received morphine (p<0.05). Shivering was significantly less common in patients who received morphine and fentanyl than in patients who are in the Control Group (p<0.02).

Conclusions

Morphine or fentanyl may be used as adjunctives to spinal anesthesia to prevent shivering in patients undergoing venous surgery.

Effects of intraoperative magnetic resonance imaging on the neuromuscular blockade of vecuronium bromide in neurosurgery

The effects of intraoperative magnetic resonance (iMR) imaging on the neuromuscular blockade of vecuronium bromide were investigated in neurosurgery. Fifty patients with American Society of Anesthesiologists grades I-II scheduled for craniotomy operation were divided into two groups (n = 25 each) with no difference in demographic data: the iMR imaging group and control group. Train-of-four (TOF) stimulation through an accelerometer was used to monitor onset, maintenance, and recovery of muscle relaxation caused by vecuronium. Vecuronium bromide was intravenously injected after anesthesia induction. The dosage of vecuronium bromide in the iMR imaging group was larger than in the control group, but not significantly. Duration of vecuronium bromide administration and operation time were significantly longer in the iMR imaging group than in the control group. Time from drug discontinuation to operation termination, and to return to neurosurgery intensive care unit were not different. Time taken by first twitch (T1) in response to TOF stimulation to recover by 25%, and muscle relaxant recovery index were significantly greater in the control group than in the iMR imaging group. The body temperature of the patients increased gradually in the iMR imaging group but decreased in the control group. iMR imaging can prolong the operation time, increase the body temperature of the patient, and remarkably shorten the clinical action time and muscle relaxation recovery index of vecuronium.

Maintaining perioperative normothermia during laparoscopic and open urologic surgery

PURPOSE

The ability to maintain normothermia during surgical procedures is crucial for improvement of the quality of patient care and the outcome of the procedure. We tested the hypothesis of whether one warming protocol is able to maintain normothermic core temperatures equally well in major open and laparoscopic urologic procedures.

PATIENTS AND METHODS

In this prospective study, 300 patients who were scheduled for open (n=53) or laparoscopic (n=247) urologic procedures were included and received intraoperative warming using a combination of an upper and lower body forced-air warmer and a single warming blanket. Core temperature was measured at baseline, at induction of anesthesia, at the start of the operation, and at the end of the operation.

RESULTS

A significant improvement in core temperature during the operation was achieved in all patients (P<0.001). There was no difference in the end-of-operation core temperature between laparoscopic and open procedures: (36.29 degrees C+/-0.03 degrees C v 36.23 degrees C+/-0.06 degrees C; P=0.224). Further, 23.3% of all patients had a core temperature of lower than 36.0 degrees C at the end of the operation (laparoscopy 23.8% v open 26.6%). Linear regression analysis revealed a correlation between duration of the operation and intraoperative core temperature (P<0.001).

CONCLUSION

The present warming protocol is effective in maintaining perioperative normothermia during major open and laparoscopic urologic procedures.

Effects of Mild Hypothermia on Blood Coagulation in Patients Undergoing Elective Plastic Surgery

BACKGROUND

The aim of this prospective, controlled study was to evaluate the effects on coagulation function of active patient warming during elective plastic surgery.

METHODS

Seventy-six patients undergoing elective plastic surgery (additive and reductive mastoplasty, rhinoplasty, and liposuction) were either covered with standard sterile drapes (control group, n = 38) or actively warmed during surgery with countercurrent fluid warming and forced-air skin warming (treatment group, n = 38). Complete evaluation of the coagulation activity was performed 1 hour before general anesthesia was induced and then at the end of surgery.

RESULTS

Although no differences in preoperative core temperature were observed (36.0 +/- 0.5 degrees C in the control group and 36.1 +/- 0.4 degrees C in the treatment group; p = 0.12), core temperature was lower at the end of surgery in the control group (34 +/- 1.0 degrees C) than in the treatment group (36 +/- 0.6 degrees C) (p = 0.0005). No differences in prothrombin time and fibrinogen plasma concentrations were observed between the two groups. At the end of surgery, control group patients showed significantly larger activated partial thromboplastin times (36.8 +/- 3.5 seconds) and bleeding times (8.1 +/- 1.6 minutes) as compared with patients maintained normothermic during surgery (34.0 +/- 2.9 seconds and 4.3 +/- 1.1 minutes; p = 0.0005 and p = 0.0005, respectively).

CONCLUSION

Actively maintaining intraoperative normothermia allows patients to maintain normal coagulation function during elective plastic surgery lasting longer than 2 hours, potentially reducing the occurrence of bleeding-related complications after plastic surgery.

The use of hypothermia as a method of neuroprotection during neurosurgical procedures and after traumatic brain injury: a survey of clinical practice in Great Britain and Ireland

Hypothermia has been employed as a method of neuroprotection for many decades. The evidence base for its use is limited, and the balance between benefit and risk is unclear. We felt that in light of this confusion it would be interesting to canvas the opinion of the members of The Neuroanaesthesia Society of Great Britain and Ireland. A questionnaire was sent to all 274 members enquiring into their use of hypothermia during a variety of different neurosurgical procedures and in the management of the head-injured patient. A 75% response rate was achieved. The results showed that over half (58%) of those who replied attempted to cool the patient during cerebral aneurysm surgery. Forty-one per cent of respondents attempt to induce hypothermia in the head-injured patient. However, for other neurosurgical procedures most felt that the disadvantages of cooling the patient outweigh the advantages. The use of hypothermia remains a contentious issue, and as yet there is no clear answer as to whether it should be employed as a method of neuroprotection.

Temperature control and recovery of bowel function after laparoscopic or laparotomic colorectal surgery in patients receiving combined epidural/general anesthesia and postoperative epidural analgesia

We compared the effects of a laparoscopic (n = 23) versus laparotomic (n = 21) technique for major abdominal surgery on temperature control in 44 patients undergoing colorectal surgery during a combined epidural/general anesthesia. A thoracic epidural block up to T4 was induced with 6-10 mL of 0.75% ropivacaine; general anesthesia was induced with thiopental, fentanyl, and atracurium IV and maintained with isoflurane. Core temperature was measured with a bladder probe and recorded every 15 min after the induction. In both groups, core temperature decreased to 35.2 degrees C (range, 34 degrees C-36 degrees C) at the end of surgery. After surgery, normothermia returned after 75 min (60-120 min) in the Laparoscopy group and 60 min (45-180 min) in the Laparotomy group (P = 0.56). No differences in postanesthesia care unit discharge time were reported between the two groups. The degree of pain during coughing was smaller after laparoscopy than laparotomy from the 24th to the 72nd observation times (P < 0.01). Morphine consumption was 22 mg (2-65 mg) in the Laparotomy group and 5 mg (0-45 mg) in the Laparoscopy group (P = 0.02). The time to first flatus was shorter after laparoscopy (24 h [16-72 h]) than laparotomy (72 h [26-96 h]) (P = 0.0005), and the first intake of clear liquid occurred after 48 h (24-72 h) in the Laparoscopy group and after 96 h (90-96 h) in the Laparotomy group (P = 0.0005). Although laparoscopic surgery provides positive effects on the degree of postoperative pain and recovery of bowel function, the reduction in heat loss produced by minimizing bowel exposure with laparoscopic surgery does not compensate for the anesthesia-related effects on temperature control, and active patient warming must also be used with laparoscopic techniques.

IMPLICATIONS

This prospective, randomized, controlled study demonstrates that laparoscopic colorectal surgery results in less postoperative pain and earlier recovery of bowel function than conventional laparotomy but does not reduce the risk for perioperative hypothermia. Accordingly, active warming must be provided to patients also during laparoscopic procedures.

An assessment of the thermal safety of microwave warming of crystalloid fluids

We performed an in vitro study to determine the thermal safety of a domestic microwave to warm intravenous crystalloid solutions. Five-hundred-millilitre bags of crystalloid, randomly allocated to groups which differed in power setting, timer setting and whether or not agitation was performed after warming, were heated in a microwave oven to a calculated temperature of 39 degrees C. Timer accuracy was checked by stopwatch. Bag temperature was measured using an infrared tympanic temperature probe and fluid temperature was measured with an in-line thermocouple. Mean times measured by stopwatch were higher than set. No in-line temperatures reached 40 degrees C. Wider overall ranges and a higher mean were found with the tympanic probe compared with in-line temperature measurement. There were significant differences between the in-line temperatures of shaken and unshaken bags at each power setting, but not when groups were added together. There was no change in colour or odour of bags or fluid. One bag developed a pinhole leak when the packaging was removed.

Effects of sympathetic blockade on the efficiency of forced-air warming during combined spinal-epidural anesthesia for total hip arthroplasty

STUDY OBJECTIVE

To evaluate if active cutaneous warming of the two upper limbs with reflex vasoconstriction is less effective in maintaining intraoperative normothermia than warming the vasodilated unoperated lower limb during combined spinal-epidural anesthesia (CSE).

DESIGN

Prospective, randomized study.

SETTING

Inpatient anesthesia at university departments of orthopedic surgery.

PATIENTS

48 ASA physical status I, II, and III patients, who were scheduled for elective total hip arthroplasty.

INTERVENTIONS

Patients received CSE with intrathecal injection of 15 mg of 0.5% hyperbaric bupivacaine. All procedures started 8 to 10 AM, and operating room temperature was maintained between 21 degrees and 23 degrees C, with relative humidity ranging between 40% and 45%. For warming therapy, patients received active forced-air warming of either the two upper limbs (Group Upper body, n = 24), or the unoperated lower limb (Group Lower extremity, n = 24). Core temperature was measured before CSE placement (baseline), and then every 30 minutes until completion of surgery. Time for fulfillment of clinical discharging criteria from the recovery area was evaluated by a blinded observer.

MEASUREMENTS AND MAIN RESULTS

Demographic data, duration of surgery, intraoperative blood losses, crystalloid infusion, and hemodynamic variables were similar in the two groups. Core temperature slightly decreased in both groups, but at the end of surgery the mean core temperature was 36.2 degrees +/- 0.5 degree C in Group Upper body and 36.3 +/- 0.5 in Group Lower extremity (NS). At recovery room arrival, seven patients in Group Upper body (29%) and three patients in Group Lower extremity (12.5%) had a core temperature less than 36 degrees C (NS). Shivering was observed in one patient in Group Upper body and in two patients in Group Lower extremity (NS). Clinical discharging criteria were fulfilled after 37 +/- 16 minutes in Group Upper body and 30 +/- 32 minutes in Group Lower extremity (NS).

CONCLUSIONS

Forced-air cutaneous warming allows the anesthesiologist to maintain normothermia during CSE for total hip replacement even if the convective blanket is placed on a relatively small skin surface with reflex vasoconstriction. Placing the forced-air warming system on the vasodilated unoperated lower limb may be troublesome to the surgeons and does not offer clinically relevant advantages in warming efficiency.