Comparison of two passive warming devices for prevention of perioperative hypothermia in dogs

Comparison of two active warming techniques on body temperature in healthy, anesthetized dogs premedicated with acepromazine or dexmedetomidine: A pilot study

Temperature regulation in dogs is significantly impaired during general anesthesia. Glabrous skin on paws may facilitate thermoregulation from this area and is a potential target for interventions attenuating hypothermia. This pilot study aimed to compare efficacy of an innovative warming device placed on the front paws (AVAcore; AVA), with no warming methods (NONE) and conventional truncal warming methods (CONV; circulating water blanket/forced air warmer) on rectal temperature and anesthetic recovery times. Dogs were premedicated with acepromazine (ACE) or dexmedetomidine (DEX), induced with intravenous propofol and maintained on isoflurane. The change in rectal temperature was statistically separated into three segments: 15 minutes following premedication, prior to induction (T0-T15), 15 minutes following anesthetic induction into isoflurane maintenance (T15-T30), and >30 minutes of isoflurane maintenance (>T30). Overall, when warming treatments and time points were combined, the decrease in rectal temperature from baseline was significantly greater with ACE than DEX (P < 0.05). When ACE and DEX were analyzed separately, changes in rectal temperatures did not differ between warming techniques at T0-T15 and T15-T30 (P > 0.05). However, at >T30 minutes, slopes of the temperature change differed between all three warming device groups, despite whether ACE or DEX was administered; temperature decreased least in CONV whereas the NONE had the largest decreases (P < 0.05). At >T30, when warming devices were considered separately, slopes of the temperature change in AVA and NONE did not differ between ACE and DEX (P > 0.050). However, in CONV, DEX had a significantly faster increase in slope than did ACE (P < 0.05). No differences in recovery times were observed between techniques or premedications (P > 0.05). Although CONV provided the most stable thermoregulation in anesthetized dogs, the AVAcore also moderated decreases in body temperature associated with general anesthesia despite premedication, providing an additional warming technique in dogs.

Peripheral warming for prevention of hypothermia in small dogs during soft tissue surgery: A randomized controlled trial

OBJECTIVE

To evaluate the effects of wrapping the extremities of small dogs with table leg covers to prevent hypothermia during anesthesia.

STUDY DESIGN

Randomized parallel-group study.

ANIMALS

A total of 60 adult dogs with a body mass <15 kg anesthetized for soft tissue surgery.

METHODS

Dogs were randomly assigned to one of two groups. The control group received routine intraoperative thermal support, while the limb-wrapping group had their peripheral limbs covered with table leg covers up to the mid-metacarpal/metatarsal region, in addition to routine thermal support. Rectal temperature during anesthesia was recorded and compared between the two groups. Data analyses were performed using Student's t-test for rectal temperature, Fisher's exact test for hypothermia incidence and analysis of covariance for the effect of limb-wrapping while taking other factors into account.

RESULTS

Thirty dogs were included per group. Rectal temperature did not differ between the groups at the time of intubation, but it was significantly higher in the limb-wrapping group (36.7 ± 1.0 °C) than in the control group (35.9 ± 0.8 °C) at the end of surgery (p = 0.003). The mean difference was 0.81 °C (95% confidence interval of mean difference 0.33-1.29 °C). The incidence of hypothermia (<37.0 °C) was significantly lower in the limb-wrapping group than in the control group (19/30 versus 28/30 dogs, respectively; p = 0.010).

CONCLUSIONS

For dogs with body masses <15 kg, limb-wrapping with table leg covers slowed the reduction in intraoperative rectal temperature. Limb-wrapping is inexpensive and easy to perform, making it a practical method for minimizing hypothermia during anesthesia in small dogs undergoing soft tissue surgery.

CLINICAL RELEVANCE

Peripheral warming with table leg covers has the potential to reduce hypothermia during soft tissue surgery in small dogs.

Supplemental reflective blankets and wool socks help maintain body temperature in dogs undergoing celiotomy procedures: a prospective randomized controlled clinical trial

OBJECTIVE

To compare results for body (esophageal) temperature measurements obtained during celiotomy in normothermic (presurgical) canine patients receiving routine heat support versus routine heat support plus supplemental support (consisting of covering the thorax in a reflective blanket and placing reflective blankets plus wool socks on 3 limbs) in a prospective randomized controlled clinical trial.

ANIMALS

44 dogs requiring celiotomy that were presented sequentially to an emergency and specialty referral veterinary hospital.

PROCEDURES

The 44 dogs undergoing celiotomy were randomly assigned to 2 groups. The control group received routine intraoperative heat support consisting of a circulating warm water blanket and either a towel or blanket. The supplemental group received the same routine heat support plus a reflective blanket covering the cervical and thoracic regions and reflective blankets wrapped around 3 limbs and covered with wool socks from the digits to the axillary or inguinal region.

RESULTS

Mean esophageal temperature for both the control and supplemental groups dropped throughout celiotomy. Esophageal temperature measurements at several time points were significantly higher for the supplemental group than for the control group. The lowest temperature measurement for the supplemental group, adjusted for initial esophageal temperature and procedure duration, was significantly higher by 0.8 °C than that for the control group.

CLINICAL RELEVANCE

Covering the cervical and thoracic regions with a reflective blanket and wrapping limbs in reflective blankets and wool socks is an affordable adjunctive method to provide passive heat support and minimize perioperative hypothermia in canine patients undergoing celiotomy.

[Common veterinary practice in small animal anesthesia - an online survey among small animal practitioners in Europe]

OBJECTIVES

Survey concerning the situation of small animal anesthesia in Europe and assessment of the compliance with the guidelines of the AVA (American Society of Anesthesiologists) and the DVG specialty group VAINS (Veterinary Anesthesia, Intensive Care, Emergency Medicine, and Pain Management).

MATERIAL AND METHODS

A link to an online survey with questions concerning anesthesia management (topics include demographics, equipment, monitoring, thermal management, pre-anesthetic examination, anesthetic protocol, and others) was sent to small animal practitioners in several countries.

RESULTS

A total of 767 evaluable questionnaires came from Germany (n = 343), Austria (n = 216), Switzerland (n = 83), the United Kingdom (n = 38), France (n = 25), Hungary (n = 25), Scandinavia (n = 23), and "other countries" (n = 11). On average, 91 % of respondents complied with the AVA guideline and 58 % complied with the VAINS specialty group guideline even before its publication. Practices/clinics with higher staff possessed superior equipment, and practices/clinics performing higher numbers of anesthesias per week were more likely to implement "good preliminary examination."

CONCLUSION AND CLINICAL RELEVANCE

Although the guidelines were found to be implemented to a certain degree, the presented study reveals a potential for optimization of the anesthesia regime in many practices/clinics, e. g. by improving the equipment or allowing for better use of present apparatus.

Pneumoperitoneum in Veterinary Laparoscopy: A Review

Objective: To review the effects of carbon dioxide pneumoperitoneum during laparoscopy, evaluate alternative techniques to establishing a working space and compare this to current recommendations in veterinary surgery. Study Design: Literature review. Sample Population: 92 peer-reviewed articles. Methods: An electronic database search identified human and veterinary literature on the effects of pneumoperitoneum (carbon dioxide insufflation for laparoscopy) and alternatives with a focus on adaptation to the veterinary field. Results: Laparoscopy is the preferred surgical approach for many human and several veterinary procedures due to the lower morbidity associated with minimally invasive surgery, compared to laparotomy. The establishment of a pneumoperitoneum with a gas most commonly facilitates a working space. Carbon dioxide is the preferred gas for insufflation as it is inert, inexpensive, noncombustible, colorless, excreted by the lungs and highly soluble in water. Detrimental side effects such as acidosis, hypercapnia, reduction in cardiac output, decreased pulmonary compliance, hypothermia and post-operative pain have been associated with a pneumoperitoneum established with CO2 insufflation. As such alternatives have been suggested such as helium, nitrous oxide, warmed and humidified carbon dioxide and gasless laparoscopy. None of these alternatives have found a consistent benefit over standard carbon dioxide insufflation. Conclusions: The physiologic alterations seen with CO2 insufflation at the current recommended intra-abdominal pressures are mild and of transient duration. Clinical Significance: The current recommendations in veterinary laparoscopy for a pneumoperitoneum using carbon dioxide appear to be safe and effective.

Effect of an intraoperative infusion of amino acids on body temperature, serum biochemistry, serum insulin and recovery variables in healthy dogs undergoing ovariohysterectomy

Change in body temperature (BT), serum biochemistry and recovery variables were compared after infusion of amino acids (AA) or lactated Ringer's solution (LRS) in dogs undergoing ovariohysterectomy. Dogs received eight parts 10 per cent AA and two parts LRS (AA, n=10) or only LRS (CG, n=10) at 10 ml/kg/hour during 90 minutes of anaesthesia. BT was measured during anaesthesia and 60 minutes of recovery. Extubation time and shivering were noted. Serum samples were obtained before anaesthesia (T0), end of anaesthesia (T90) and 18 hours after (T18h). Friedman, Mann-Whitney, Kruskal-Wallis or Fisher's exact tests were used for analysis. A decrease in BT of -2.16 (-1.59 to -3.24)°C for group AA and -2.79 (-1.98 to -4.52)°C for group CG was different (P=0.02). Time to extubation was 5 (3-9) minutes for group AA and 9 (5-15) minutes for group CG and was different (P=0.01). Only 30 per cent of dogs in group AA and 100 per cent of dogs in group CG shivered during recovery (P=0.003). Glucose, insulin and blood urea nitrogen at T90 were higher than T0 and T18h for group AA. Dogs receiving intraoperative infusion of AA had a higher BT, extubated sooner and shivered less than control dogs at recovery from anaesthesia.

Effect of peritoneal lavage solution temperature on body temperature in anaesthetised cats and small dogs

A prospective, randomised, non-blinded, clinical study to assess the effect of peritoneal lavage using warmed fluid on body temperature in anesthetised cats and dogs of less than 10 kg body mass undergoing coeliotomy. A standardised anaesthetic protocol was used. Oesophageal and rectal temperatures were measured at various time points. At the end of surgery, group 1 patients (n=10) were lavaged with 200 ml/kg sterile isotonic saline at 34±1°C and group 2 (n=10) at 40±1°C. Groups were similar with respect to age, mass, body condition and surgical incision length. Duration of anaesthesia, surgical procedures and peritoneal lavage was similar between groups. Linear regression showed no significant change in oesophageal temperature during the lavage period for group 1 (P=0.64), but a significant increase for group 2 patients (P<0.0001), with mean temperature changes of -0.5°C (from (36.3°C to 35.9°C) and +0.9°C (from 35.4°C to 36.3°C), respectively. Similar results were found for rectal temperature, with mean changes of -0.5°C and +0.8°C (P=0.922 and 0.045), respectively. The use of isotonic crystalloid solution for peritoneal lavage at a temperature of 40±1°C significantly warms small animal patients, when applied in a clinical setting, compared with lavage solution at 34±1°C.