Comparison of intraperitoneal and incisional lidocaine or ropivacaine irrigation for postoperative analgesia in dogs undergoing major abdominal surgeries

This study compared the postoperative analgesic efficacy of intraperitoneal and incisional lidocaine versus ropivacaine in dogs undergoing major abdominal surgeries. Dogs randomly received intraperitoneal lidocaine irrigation (4 mg kg-1, diluted to 5 ml kg-1, L group), ropivacaine (4 mg kg-1, diluted to 5 ml kg-1, R group) or 0.9% saline (5 ml kg-1, C group). Prior to skin closure, dogs received incisional lidocaine 2 mg kg-1 (group L), incisional ropivacaine 2 mg kg-1 (group R) or incisional saline 0.2 ml kg-1 (group C). Pain was assessed at different time points up to 24 hours after extubation, using the Short Form-Glasgow Composite Measure Pain Scale and VAS Scale. In group C, postoperative pain scores were significantly higher than in groups L and R from T0.5 to T6 (p < 0.05). In R group, postoperative pain scores were significantly lower than in groups L and C from T12 to T24 (p < 0.05). Rescue analgesia was administered to 5/11 dogs in L group, 1/10 dogs in R group and 8/10 dogs in C group. Groups L and R experienced a significantly lower postoperative pain during the first 6 hours after extubation, compared with group C. Ropivacaine provided lower postoperative pain scores than lidocaine and saline up to 24 hours after extubation. According to the obtained results, ropivacaine seemed to provide better and longer lasting postoperative analgesia compared with lidocaine. Therefore, intraperitoneal and incisional administration of ropivacaine in dogs undergoing major abdominal surgeries is recommended.

Evaluation of ultrasound-guided pecto-intercostal block in canine cadavers

OBJECTIVE

To describe the technique for performing an ultrasound-guided pecto-intercostal fascial (PIF) block and compare two volumes of injectate in canine cadavers.

STUDY DESIGN

Prospective experimental cadaveric study.

ANIMALS

A total of 11 canine cadavers (11.8 ± 1.9 kg).

METHODS

Parasternal ultrasound-guided injections were performed within the PIF plane, between the deep pectoral and external intercostal muscles, at the intercostal space between ribs four and five. Each hemithorax was injected with 0.25 mL kg-1 (treatment low volume, LV) or 0.5 mL kg-1 (treatment high volume, HV) of 1% methylene blue dye. Treatments were randomly assigned to either right or left hemithorax, with each cadaver injected with both treatments, for a total of 22 injections. Anatomical dissections were performed to determine staining of ventral cutaneous branches of intercostal nerves, surrounding nerves and musculature and spread of injectate. The presence or absence of intrathoracic puncture was also noted.

RESULTS

The PIF plane was identified and injected in each hemithorax. No significant differences between treatments LV and HV were found for number of ventral cutaneous nerve branches stained or any other analyzed variable. The ventral cutaneous branches of intercostal nerves (T3-T8) were variably stained, and the most commonly stained nerves were T5 (6 and 10), T6 (8 and 9) and T7 (2 and 7) in treatments LV and HV, respectively. Staining outside the immediate parasternal region was noted in both treatments, with greater spread away from the parasternal region in treatment HV. No intrathoracic staining was found.

CONCLUSIONS AND CLINICAL RELEVANCE

Ultrasound-guided PIF injections resulted in staining of ventral cutaneous branches and parasternal musculature; however, the spread observed was inadequate to provide effective analgesia to the sternum. In vivo studies are warranted to investigate this regional anesthetic technique in veterinary patients.

Closure of defects in a geometric figure pattern associated with tumescent anesthesia with lidocaine in rabbits (Oryctolagus cuniculus)

Abstract The use of tumescent anesthesia with lidocaine can provide better intra- and postoperative analgesia that would benefit extensive reconstructive surgery. However, lidocaine can interfere with the healing process. Therefore, this study aimed to assess the local interference of the healing of induced and closed skin defects in a geometric pattern associated with the use of tumescent anesthesia with lidocaine in rabbits. Furthermore, we assessed its influence on cardiorespiratory parameters and postoperative analgesia. This study included 27 rabbits divided into three groups: GC (without the use of tumescence), GS (use of tumescence with 0.9% NaCl solution), and GL (use of tumescent anesthesia with lidocaine). There was no statistically significant intergroup difference in any stage of the wound healing process on macroscopic evaluations, in the angiogenesis process, or in the process of collagenization and fibroblast deposition. There were significant differences in heart rate (lower in GL), respiratory rate (higher in GC), mean arterial pressure (higher in GL), and expired concentration of isoflurane (lower in GL). There was no significant intergroup difference in the von Frey filament test or the visual analog scale score used to evaluate postoperative analgesia. We concluded that tumescent anesthesia with lidocaine does not impair postoperative tissue repair. Its use features benefits such as reducing the volume of inhaled anesthetic, maintaining the anesthesia plan, stable heart and respiratory rates, and lower hypotension during the surgical procedure.

Constant Rate Infusion of Lidocaine, Tumescent Anesthesia and Their Combination in Dogs Undergoing Unilateral Mastectomy

Tumescent anesthesia (TUM) is a technique that was initially used to perform liposuction under local anesthesia, which consists of the injection of such large volumes of local anesthetic until to produce swelling and firmness (tumescence) of the surgical area. The aim of this study was to compare the intraoperative analgesic efficacy of lidocaine (LID) constant rate infusion (CRI), of TUM, or their combination (LID/TUM) and the postoperative pain and analgesic requirement in dogs undergoing unilateral mastectomy. Twenty-four dogs were premedicated with dexmedetomidine (3 μg/kg) and methadone (0.2 mg/kg) intravenously (IV). After induction with propofol IV to effect, dogs were randomly allocated to receive a loading dose of lidocaine (2 mg/kg) followed by a CRI of 100 μg/kg/min (Group LID) in addition to an equivalent volume of lactated Ringer's solution instead of local TUM; a loading dose of lactated Ringer's solution followed by a CRI of Ringer's solution in addition to TUM (Group TUM); a loading dose of lidocaine (2 mg/kg) followed by a CRI of 100 μg/kg/min in addition to TUM (Group LID/TUM). Anesthesia was maintained with isoflurane in oxygen. Postoperative pain scores were assessed once the dogs had fully recovered from the sedative effects, and following 15, 30, 45 and 60 min. The results of the current study allow us to assert that all three treatments provided satisfactory intraoperative antinociceptive effects but administration of LID/TUM induced greater inhibition on sympathetic stimulating effect up to 60 min from recovery, thus, providing better early postoperative pain relief in dogs undergoing mastectomy.

Evaluation of tumescent local anesthesia in cats undergoing unilateral mastectomy

OBJECTIVE

To evaluate the analgesic efficacy and safety of tumescent local anesthesia (TLA) in cats undergoing unilateral mastectomy.

STUDY DESIGN

Prospective clinical trial.

ANIMALS

A total of 12 ovariohysterectomized female cats.

METHODS

All animals were premedicated with pethidine (4 mg kg^-1) intramuscularly (IM), followed by induction of anesthesia with propofol (5 mg kg^-1) intravenously and maintenance with isoflurane in oxygen. A refrigerated TLA solution (15 mL kg^-1, 8 °C) was injected using a Klein cannula. The solution was composed of 0.5 mL of epinephrine (1 mg mL^-1) and 40 mL of 2% lidocaine added to 210 mL lactated Ringer's solution (final lidocaine concentration 0.32%). Heart and respiratory rates, systolic arterial blood pressure, temperature and oxygen saturation were measured during anesthesia. Blood samples were collected from the jugular vein for measurement of plasma lidocaine concentration using high performance liquid chromatography. Postoperative pain scores were evaluated hourly for 6 hours. Analgesic rescue was performed with tramadol (2 mg kg^-1) IM and meloxicam (0.15 mg kg^-1) subcutaneously.

RESULTS

Plasma lidocaine concentration peaked at 90 minutes after injection of TLA, but no concentration considered toxic for the species was measured. The median postoperative analgesia time was 6 hours after injection of TLA.

CONCLUSIONS

This study found that TLA prevented sympathetic response to noxious stimuli during anesthesia and provided satisfactory postoperative analgesia in cats submitted to total unilateral mastectomy, with no apparent signs of toxicity.

CLINICAL RELEVANCE

TLA can prevent sympathetic stimulation resulting from noxious stimuli during anesthesia, promoting good intraoperative conditions, proving to be a viable addition to analgesia in cats submitted to a total unilateral mastectomy.

Tumescent anesthesia or epidural anesthesia combined with intercostal block in bitches submitted to mastectomy

Abstract The present study aimed to evaluate the use of tumescent local anesthesia or epidural anesthesia associated with an intercostal nerve block in bitches submitted to mastectomy. Fourteen bitches from the clinical routine of the Veterinary Hospital of the Federal University of Pelotas were premedicated with acepromazine (0.03 mg/kg) and morphine (0.3 mg/kg) intramuscularly, then induced with propofol (2 to 6 mg/kg/IV) and maintained with 1,4V% isoflurane (calibrated vaporizer). The patients were randomly allocated into: GALT Group (n=7), which received tumescent local anesthesia (0.16%) at the dose of 15 mL/kg, and the GEBI Group (n=7) which received epidural anesthesia with lidocaine (5 mg/kg) and morphine (0.1 mg/kg) associated with an intercostal nerve block from the 6th to 12th intercostal space with lidocaine (2 mg/kg). An increase higher than 10% in heart rate, respiratory rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure were considered as possible signs of nociception, to which fentanyl was administered intravenously as rescue analgesia. Postoperative analgesia was evaluated by means of the modified Glasgow scale at 30, 60, 120, 240 and 360 minutes. There were no differences in physiological parameters (0>0.05) in the transoperative period intra-group and inter-group the groups. The GEBI Group required more frequent transoperative rescue analgesia (9) in comparison to the GALT Group (5), but with no statistical difference. During the postoperative period, there was no need for rescue analgesia in either group. Results suggest that epidural anesthesia associated with intercostal nerve block can be used as an alternative technique in patients with restrictions against the use of local tumescent anesthesia.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.