Comparison of perioperative analgesic protocols for dogs undergoing tibial plateau leveling osteotomy

Review of intra-articular local anaesthetic administration in horses: Clinical indications, cytotoxicity, and outcomes

Equine practitioners frequently inject local anaesthetics (LA) intra-articularly in both diagnosis of lameness and for pain management intra- or post-operatively with synovial endoscopy. Recent reviews of the human and veterinary literature support the concept that chondrotoxicity of LA on joint tissues depends on the type of drug, dose administered, and duration of exposure. The purpose of this review is to summarise the current literature describing intra-articular local anaesthetic use, including both in vitro and in vivo studies, and to draw some comparisons to literature from other species where potential toxicity and duration of effect have been evaluated with the goal of advancing the field's understanding of intra-articular local anaesthetic use in horses, and indicating future directions for the field. The aggregate data available from all species, while generally sparse for horses, indicate that LA are rapidly cleared from the synovial fluid after injection, often within 30 min. In vitro data strongly suggest that lidocaine and bupivacaine are likely more chondrotoxic than other LA, although to what extent is still unknown, and cytotoxicity of LA may be mitigated through concurrent injection with HA, PRP, and drug combinations including nonsteroidal anti-inflammatories and opioids. The current body of in vitro research is not reflective of the in vivo environment, and further in vitro work, if performed, should focus on mimicking the native joint environment, utilising PK data and joint/injection volumes to replicate the native environment more accurately within the joint and the expected exposures to LA.

Clinical effects of perineural dexmedetomidine or magnesium sulphate as adjuvants to ropivacaine in dogs undergoing tibial plateau leveling osteotomy

The study aimed to compare the quality of perioperative analgesia, the motor block duration, and the effects on main cardiovascular parameters of dexmedetomidine (1 μg/kg/nerve block) or magnesium sulphate (2 mg/kg/nerve block) as adjuvants to 0.3% ropivacaine for sciatic and saphenous nerves block in dogs undergoing tibial plateau leveling osteotomy (TPLO). Dogs randomly received perineural dexmedetomidine-ropivacaine (D group), magnesium sulphate-ropivacaine (M group), or ropivacaine (C group). Fentanyl was administered in case of intraoperative nociception. Postoperative pain was assessed using the Short Form-Glasgow Composite Measure Pain Scale (SF-GCMPS) and VAS scale. The duration of motor blockade and intra- and postoperative cardiovascular parameters were also recorded. Group M required significantly more fentanyl than D group (p = 0.04). Group M had a significantly higher SF-GCMPS score than group C at 4 (p = 0.002) and 5 h after extubation (p = 0.01), and a significantly higher VAS score than group D at 3 h after extubation (p = 0.03), and at 4 h if compared to group C (p = 0.009). No significant differences regarding the duration of motor blockade were detected between groups (p = 0.07). The heart rate was significantly lower in group D than in M and C groups intraoperatively and during the first 1.5 h post extubation. The addition of dexmedetomidine or magnesium sulphate as adjuvants to perineural ropivacaine did not improve the quality of perioperative analgesia and did not prolong the motor blockade in dogs undergoing sciatic and saphenous nerves block for TPLO surgery.

Incidence of postoperative administration of opioids in dogs undergoing a tibial plateau leveling osteotomy after intra-operative liposomal bupivacaine administration with or without morphine epidural

OBJECTIVE

To determine the influence of two intraoperative pain management protocols on the need for additional opioids in patients receiving an epidural and periarticular liposomal bupivacaine (PLB) vs. PLB alone in the 12-24 h period after undergoing a TPLO.

STUDY DESIGN

Retrospective study.

ANIMALS

One hundred seventy-four dogs with cranial cruciate ligament tears presenting for TPLO.

METHODS

Medical records of dogs presenting for a unilateral or bilateral cranial cruciate ligament tear who had a TPLO performed were reviewed for signalment, weight, body condition score, and peri-operative pain management protocol. Dogs were divided into two groups: those who received an epidural and PLB, and those who received only PLB. Post-operative opioid administration was recorded for each group.

RESULTS

Patients who received an epidural and PLB received fewer postoperative opioids. There were 36% fewer opioid injections administered to dogs who received epidurals compared to dogs who did not receive epidurals (IRR) (95% CI) = 0.64 (0.45-0.92), P = 0.02). BCS was not a significant predictor of the post-operative opioid requirement (IRR (95% CI) = 1.3 (0.75-2.4), P = 0.38). When adjusting for BCS as a possible confounder, there were 39% fewer opioid injections in dogs who received epidurals than dogs without (IRR (95% CI) = 0.61 (0.42-0.88), P = 0.009).

CONCLUSIONS

The incidence of postoperative opioid administration was significantly diminished in patients receiving both an epidural and PLB.

CLINICAL SIGNIFICANCE

Administration of an epidural in addition to infiltration of PLB significantly decreased the incidence of postoperative opioid administration in dogs undergoing a TPLO.

Contribution to the Study of Perioperative Factors Affecting the Restoration of Dog's Mobility after Femoral Head and Neck Excision: A Clinical Study in 30 Dogs

This study aimed to compare postoperative analgesia and the time of limb weight bearing induced by the intraoperative administration of a local anesthetic at the site of the femoral head and neck excision (FHNE) in dogs, with and without the administration of preoperative epidural anesthesia. Additionally, the impact of postoperative opioid drug administration on weight-bearing time was examined. This randomized, blinded, prospective clinical study included 30 client-owned dogs. The dogs were randomly divided into three groups (A, B, C), each further divided into two subgroups (A1, A2, B1, B2, C1, C2). Group A received epidural anesthesia and ropivacaine at the ostectomy site, Group B received only ropivacaine, and Group C served as the control group. Subgroup 1 received a non-steroidal anti-inflammatory drug postoperatively, while Subgroup 2 had tramadol added to their regimen. Pain assessment was conducted using the University of Melbourne Pain Scale (UMPS) and an algometer. The study concluded that multimodal analgesia, utilizing all the aforementioned analgesic techniques, resulted in faster limb weight bearing for dogs undergoing FHNE.

Case report: Paralysis after epidural analgesia due to a hemorrhage of pure epidural venous hemangioma

Purpose

To report a case of sudden paralysis after epidural analgesia to raise awareness of the condition and the importance of early identification and appropriate treatment of extradural venous angiomas.

Clinical features

A 28-year-old man with myofascial pain syndrome experienced paraplegia after receiving an epidural block for pain relief, which was later discovered to be caused by hemorrhage from extradural venous angiomas. Decompression surgery was performed immediately and successfully. A follow-up examination was performed 5 months after surgery. The patient reported improvement in urinary retention. The muscle strength in both his lower extremities had recovered to 4 out of 5 but still exhibited considerable residual spasticity.

Conclusions

Before administering epidural analgesia to relieve undetermined pain, it is prudent to carefully weigh potential benefits against potential risks to patient health to minimize the likelihood of complications.

Intra-articular methylprednisolone and bupivacaine for treatment of sesamoid disease in dogs

INTRODUCTION

The sesamoid disease is a cause of lameness in dogs, and there is limited literature relating to diagnosis, treatment and outcome of treatment in dogs with the sesamoid disease. Our aim was to compare the efficacy of intra-articular metacarpophalangeal/metatarsophalangeal joint injection with methylprednisolone and bupivacaine (IMPB) or conservative management with nonsteroidal anti-inflammatories and rest (CMNR) for treatment of this disease.

MATERIALS AND METHODS

We conducted a retrospective survey of dogs treated for the sesamoid disease with IMPB or CMNR. The medical records of all dogs that received IMPB or were recommended CMNR for treatment of sesamoid pain were reviewed, and a client questionnaire was delivered to owners. Response to treatment, rapidity of response, length of resolution and recurrence of clinical signs associated with the sesamoid disease were assessed.

RESULTS

A total of 78 dogs were included in the study. One week after IMPB, 52/58 (89.7%) dogs demonstrated resolution of lameness compared with 1 week of CMNR, 0/18 (P < 0.001). There was limited statistical evidence in client satisfaction between treatment groups, IMPB 36/53 (67.9%) and CMNR 16/17 (94%) (P = 0.052). Dogs presenting with the sesamoid disease had comorbidities in 51/78 (65.4%) of cases. Elbow disease was the most common comorbidity 29/78 (37.2%).

CONCLUSION

Our results support the use of IMPB for short-term (1 week) resolution of lameness associated with sesamoid disease in dogs. Dogs treated with CMNR had slower improvement; however, there was no difference in lameness or client satisfaction between treatment groups at long-term follow-up (12 months).

Onset of Action of Bupivacaine Administered via Dural Puncture Epidural versus Spinal, Lumbosacral, and Sacrococcygeal Epidural Injections in Dogs: Randomised Clinical Trial

Simple Summary

Epidural anaesthesia is commonly performed to provide long-lasting local anaesthesia in animals. Spinal anaesthesia has become popular in human anaesthesia due to a faster onset, but shorter duration, than epidural anaesthesia. Recently, dural puncture epidural anaesthesia (DPE) has been proposed as a compromise between spinal and epidural anaesthesia, providing longer duration than spinal anaesthesia with similar onset of action. This study aimed to compare the technical aspects of these techniques (onset of action, number of attempts, and time to perform them). The results showed no difference between the techniques in number of attempts required, while the epidural injections tended to be shorter than spinal and dural puncture epidural injections. The onset of action (measured as disappearance of the patellar reflex) was longer in the sacrococcygeal epidural injection than any other techniques (including lumbosacral epidural injections).

Abstract

The study aimed to compare bupivacaine onset time when administered via epidural anaesthesia injecting both at the lumbosacral and sacrococcygeal spaces, spinal anaesthesia, and DPE in clinical dogs. A total of 41 dogs requiring neuraxial anaesthesia as part of their anaesthetic protocol were recruited. They were randomly allocated to receive an epidural injection in the sacrococcygeal space aided by the nerve stimulator (SCO), an epidural injection in the lumbosacral (LS), a subarachnoid injection (SPI), or a DPE. The onset of anaesthesia was assessed every 30 s after the injection by testing the presence of patellar ligament reflex. The number of attempts and time to perform the technique were also recorded. Data were analysed using a one-way ANOVA for trimmed means with post hoc Lincoln test and a Kaplan–Meier curve. The significance level was set at p < 0.05, and the results are presented in absolute values and median (range). There was no difference in the number of attempts required to complete the techniques between groups (p = 0.97). Epidural injections (LS and SCO) tended to be shorter than SPI and DPE techniques, but there was no statistically significant difference (p = 0.071). The time to the disappearance of patellar ligament reflex (Westphal’s sign) in the SCO group was longer than in any other group. In conclusion, all techniques provided a rapid block of the patellar reflex. The SCO technique was the slowest in onset, while the other groups (SPI, DPE, and LS) were faster and almost indistinguishable.

Evaluation of perfusion index as a noninvasive tool to determine epidural anesthesia effectiveness in dogs

OBJECTIVE

To evaluate perfusion index (PI) as a noninvasive tool to determine effectiveness and onset of epidural anesthesia in dogs.

STUDY DESIGN

Prospective clinical trial.

ANIMALS

A total of 21 adult dogs, aged 6.5 ± 3 years and weighing 34.9 ± 6.4 kg, undergoing a tibial plateau leveling osteotomy.

METHODS

Dogs were premedicated intramuscularly with acepromazine (0.03 mg kg^-1) and hydromorphone (0.1 mg kg^-1) and anesthetized with intravenous propofol (to effect) and isoflurane in oxygen. A surface transflectance probe was secured to the tail base to monitor PI and a dorsal pedal artery catheter was placed for invasive blood pressure monitoring. A lumbosacral epidural was performed with the dog in sternal recumbency. Dogs were randomly assigned for inclusion of epidural morphine (0.1 mg kg^-1) or morphine (0.1 mg kg^-1) and lidocaine (4 mg kg^-1). PI was recorded following instrumentation of each dog just prior to the epidural (baseline), at 10 minute intervals for 30 minutes, before and after the surgical skin incision and before and after completion of the osteotomy. Physiological variables and end-tidal isoflurane were recorded at the same time points.

RESULTS

There was no significant difference in PI between the groups at any time point. There was a significant change in end-tidal isoflurane before and after the skin incision in the epidural morphine and epidural morphine-lidocaine groups (p = 0.04, p = 0.05, respectively) and before and after the osteotomy in each group for heart rate (p = 0.001, p = 0.04), diastolic (p = 0.01, p = 0.01) and mean arterial blood pressure (p = 0.03, p = 0.05).

CONCLUSIONS AND CLINICAL RELEVANCE

PI did not provide an objective means for determining the onset or effectiveness of epidural anesthesia in anesthetized dogs and alternate methods of noninvasive assessment should be investigated.

Post-operative analgesia following TPLO surgery: A comparison between cimicoxib and tramadol

OBJECTIVE

To compare the analgesic effects of oral administration of cimicoxib and tramadol over a 30 day period following Tibial Plateau Leveling Osteotomy and partial menisectomy in dogs.

DESIGN

Randomized, double blinded, prospective clinical trial.

ANIMALS

42 adult client-owned dogs with unilateral cranial cruciate ligament disease and partial meniscal tears.

METHODS

Dogs were allocated into 2 treatment groups (cimicoxib or tramadol). Weight bearing while standing, thigh circumference, flexion and extension range of motions, wound classification, adverse effects, Visual Analogue Scale (VAS), Glasgow Composite Measure Pain Scale (CMPS-SF) and Helsinki Chronic Pain Index (HCPI) questionnaire and limb function by means of pressure platform gait analysis were recorded before surgery and at several time points after surgery for 30 days. Outcome measures were compared at each time point among groups.

RESULTS

A significant improvement in two objective measures of gait of the cimicoxib group: the vertical impulse on day 1 and day 20 and the peak vertical force on day 20 were significantly improved when compared to the tramadol group. However, no difference was seen for the VI or PVF of dogs on the other days compared. In addiction there was no difference in the weight bearing while standing, thigh circumference, wound classification, adverse effects, VAS, CMPS-SF and HCPI. We did not observe a difference in the number of adverse effects measured in this study with the exception of hock edaema.

CONCLUSIONS AND CLINICAL RELEVANCE

A significant difference was not found in long-term postoperative analgesia provided by cimicoxib or tramadol in dogs undergoing TPLO when subjective parameters (with the exception of knee joint range of motion) were evaluated, but use of the force plate analysis revealed a significant difference between groups at T20 for both PVF and VI. The use of cimicoxib improved the limb function and ROM and reduced the occurrence of hock edema, in the first 20 days after surgery, without any additional side effects, compared to tramadol. Thus, the use of cimicoxib should be preferred to tramadol alone in clinical cases similar to the ones included in this study.

Effects of perioperative saphenous and sciatic nerve blocks, lumbosacral epidural or morphine-lidocaine-ketamine infusion on postoperative pain and sedation in dogs undergoing tibial plateau leveling osteotomy

OBJECTIVE

To compare the quality of postoperative analgesia and sedation after preoperative saphenous and sciatic nerve blockade, preoperative lumbosacral epidural injection and perioperative intravenous (IV) morphine, lidocaine and ketamine infusions in dogs undergoing stifle arthroscopy and tibial plateau leveling osteotomy (TPLO) under general anesthesia.

STUDY DESIGN

Prospective, blinded, randomized, clinical comparison study.

ANIMALS

A total of 45 dogs weighing 33.9 (15.9-56.7) kg and aged 5.2 (1.0-12.0) years, mean (range), undergoing elective unilateral TPLO for spontaneous cranial cruciate ligament rupture.

METHODS

Client-owned dogs were enrolled. Dogs were randomly assigned to one of three groups: group MLK, perioperative IV morphine, lidocaine and ketamine infusion; group EPID, lumbosacral epidural with ropivacaine and morphine; or group SSNB, saphenous and sciatic nerve blockade with ropivacaine. Routine stifle arthroscopy followed by TPLO surgery was performed. Sedation and pain scores were assessed at 0, 2, 4, 8 and 24 hours following extubation. Rescue analgesia was administered as prescribed by Glasgow composite pain score-short form score >5.

RESULTS

Sedation scores for MLK were higher than EPID and SSNB. Pain scores for SSNB were lower than those for EPID and MLK. No significant differences were found in anesthesia duration or surgery duration among groups. No dogs required rescue analgesia.

CONCLUSIONS AND CLINICAL RELEVANCE

Although analgesia was adequate in all groups, the best combination of analgesia without increased sedation was recorded for SSNB.

Effects of Cryotherapy on Temperature Change in Caudal Thigh Muscles of Dogs

OBJECTIVE

 The aim of the study reported here was to determine the effect of cryotherapy on the caudal thigh muscles of dogs. We hypothesized that temperature changes would be greatest in superficial tissues and decrease with tissue depth.

STUDY DESIGN

 Eight mixed-breed dogs (mean weight 21.2 kg, mean age 3.3 years) were studied. Temperature was measured at the skin surface and at depths of 1.0 and 3.0 cm below the skin using needle thermistor probes that were inserted beneath the site of cold pack application. Treatment consisted of a standard 1.0°C cold pack applied for 20 minutes. Temperature was recorded every minute for the 20 minute cold pack treatment, and for 80 minutes following treatment.

RESULTS

 Cutaneous temperatures significantly decreased (p < 0.01), with rapid rewarming of the skin following cold pack removal. Tissue cooling was less profound with increasing tissue depths, but was still significant (p < 0.05). There was no significant difference in muscle temperature between haired and clipped limbs.

CONCLUSION

 A single application of a cold pack to the caudal thigh muscles of dogs for 20 minutes resulted in significant temperature reduction at all tissue depths (p < 0.05). This decrease persisted for ∼60 minutes. The presence of hair did not have a significant effect on muscle cooling (p > 0.05).

Effect of bupivacaine concentration and formulation on canine chondrocyte viability in vitro

OBJECTIVE

To quantitate bupivacaine concentration and formulation effects on chondrocyte viability in vitro.

STUDY DESIGN

Controlled laboratory study.

SAMPLE POPULATION

Primary canine chondrocyte isolates.

METHODS

Cell passage 3 and 4 canine chondrocytes were exposed to 0.9% saline; canine chondrocyte growth medium; 0.4, 0.5, 0.6, 1.5, 2.5, 3.5, or 5 mg/mL preservative-free standard formulation bupivacaine (SFB); or 13.3 or 6.65 mg/mL liposomal encapsulated bupivacaine (LEB) for 1 hour. Chondrocyte viability and clonogenicity were quantitated with 3-(4,5-dimethylthiazol-2-31 yl)-2,5-diphenyltetrazolium bromide (MTT) and clonogenic assays, respectively. Differences among concentrations and formulations were assessed with Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner post hoc tests.

RESULTS

Growth medium had the highest cell viability based on MTT metabolism. Similarly, all LEB concentration groups had higher cell viability compared with SFB concentration cells treated with 3.5 or 5 mg/mL SFB (P < .03). Among SFB concentrations, cell viability was higher at 0.6 mg/mL compared with at 2.5 mg/mL or greater (P < .03). Cell clonogenicity was not significantly different between saline, culture medium, or 0.5 mg/mL SFB. Clonogenicity was lower with all tested LEB concentrations compared with saline or medium (P < .02).

CONCLUSION

In vitro toxicity of SFB on canine chondrocytes is concentration dependent. Liposomal encapsulated bupivacaine may have time-dependent effects resulting in chondrotoxicity.

CLINICAL SIGNIFICANCE

Clinically relevant concentrations of SFB after a single injection may not result in chondrotoxic effects in vitro. Liposomal encapsulated bupivacaine should not be used in the articular environment.

Intra-articular use of analgesic/antinflammatory drugs in dogs and horses

Joint pain is a major cause of lameness in animals such as horses and dogs, and it may affect their athletic performance and quality of life. The intra-articular administration of analgesic/antinflammatory drugs is a common practice in veterinary medicine, for both lameness diagnosis and joint pain management. It is used either perioperatively, such as in animals undergoing arthroscopy/arthrotomy, and in osteoarthritic animals. However, evidence regarding efficacy and safety of each drug is limited, and controversies persist in these areas. In particular, it is often uncertain whether a defined treatment is effective by simply relieving the symptomatic pain associated with the joint disease, or whether it has a positive effect on the joint environment. Moreover, there is still much hesitation about treatments for joint diseases, related to the time of their application for the best outcome, and to any possible deleterious side effects. This article includes a review of the literature concerning the main analgesic/antinflammatory drugs used intra-articularly for managing acute and chronic joint pain/inflammation in dogs and horses. Three main issues for each class of drugs are considered, including clinical efficacy, pharmacokinetics, and local cytotoxic effects.

Comparison of liposomal bupivacaine and 0.5% bupivacaine hydrochloride for control of postoperative pain in dogs undergoing tibial plateau leveling osteotomy

OBJECTIVE

To compare liposome-encapsulated bupivacaine (LEB) and (nonliposomal) 0.5% bupivacaine hydrochloride (0.5BH) for control of postoperative pain in dogs undergoing tibial plateau leveling osteotomy (TPLO).

ANIMALS

33 client-owned dogs.

PROCEDURES

In a randomized clinical trial, dogs undergoing TPLO received LEB (5.3 mg/kg [2.4 mg/lb]) or 0.5BH (1.5 mg/kg [0.68 mg/lb]) by periarticular soft tissue injection. All dogs received carprofen (2.2 mg/kg [1 mg/lb], SC, q 12 h) beginning at extubation. Signs of pain were assessed at extubation and predetermined times up to 48 hours later with the Colorado State University-Canine Acute Pain Scale and Glasgow Composite Pain Scale-Short Form. A pressure nociceptive threshold device was used at the affected stifle joint before surgery and at 5 postoperative time points. Methadone (0.1 mg/kg [0.05 mg/lb], IV) was administered if the Colorado State University pain scale score was ≥ 2 (scale, 0 to 4). Surgical variables; pain scores; pressure nociceptive thresholds; times to first administration of rescue analgesic, first walk, and first meal consumption; and total opioid administration were compared between treatment groups.

RESULTS

28 dogs completed the study. Dogs administered LEB were less likely to require rescue analgesia and received lower amounts of opioids than dogs administered 0.5BH. There were no significant intergroup differences in other measured variables.

CONCLUSIONS AND CLINICAL RELEVANCE

The LEB appeared to provide adequate analgesia after TPLO with lower requirements for opioid treatments, which may allow dogs to be discharged from the hospital earlier than with traditional pain management strategies.

The influence of the choice of preemptive analgesia on long-term postsurgical pain after tibial plateau leveling osteotomy in dogs

OBJECTIVE

To evaluate the prevalence of chronic postsurgical pain (CPSP) after tibial plateau leveling osteotomy (TPLO) in dogs and to determine the influence of preemptive locoregional analgesia on CPSP.

STUDY DESIGN

Retrospective study.

ANIMALS

One hundred twenty client-owned dogs.

METHODS

Medical records of dogs that underwent TPLO between 2012 and 2016 were reviewed for demographic information and type of preemptive analgesia. Owners were contacted to retrospectively assess the quality of life of their dogs by using the Helsinki Chronic Pain Index (HCPI) before and 6 months after surgery and at the time of questioning. An HCPI score > 12 was considered indicative of CPSP. Medical records were reviewed for demographic information and type of preemptive analgesia. A cumulative logit model was used to assess correlation of type of perioperative analgesia, HCPI, and demographic data.

RESULTS

The HCPI score was consistent with CPSP in 41 of 101 dogs with long-term follow-up (2.9 ± 1.5 years after surgery). Chronic postsurgical pain was documented in 11 of 32 and 13 of 28 dogs that received a spinal or epidural injection, respectively, or in 28 of 80 and 25 of 67 dogs with sciatic-femoral block at 6 months or with long-term follow-up after TPLO, respectively (P > .05). A negative correlation was found between HCPI and both weight and age 6 months after surgery. Only weight remained negatively correlated 2.9 years after surgery.

CONCLUSION

Forty-one percent of dogs that were evaluated exhibited HCPI values compatible with CPSP long-term after TPLO, regardless of the type of preemptive analgesia. Increased body weight was a negative prognostic factor for CPSP development.

CLINICAL SIGNIFICANCE

Additional studies are required to evaluate CPSP development after TPLO.

Epidural and Spinal Anesthesia

Epidural and spinal anesthesia with a combination of local anesthetics and opioids (when available) is a commonly used technique in veterinary medicine and a safe one when practiced under strict guidelines. It is a valuable tool in the analgesic armamentarium and can greatly extend the ability to provide analgesia and reduce postoperative opioid requirements. As with all regional anesthetic techniques, clinical experience should be gained in order to practice it efficiently, and care should be taken to minimize the risks and complications associated with its use.

Comparison of ultrasound-guided lumbar plexus and sciatic nerve blocks with ropivacaine and sham blocks with saline on perianesthetic analgesia and recovery in dogs undergoing tibial plateau leveling osteotomy surgery

OBJECTIVE

To assess the effects of ultrasound-guided lumbar plexus and sciatic nerve blocks on perianesthetic analgesia and recovery quality in dogs undergoing tibial plateau leveling osteotomy (TPLO).

ANIMALS

A group of twenty 20 dogs.

STUDY DESIGN

Prospective, randomized, blinded, clinical study.

METHODS

Dogs were administered lumbar plexus and sciatic nerve blocks with ropivacaine (1.5 mg kg^-1; group RA) or sham blocks with saline (group CON). Dogs were administered hydromorphone (0.2 mg kg^-1) and atropine (0.02 mg kg^-1) subcutaneously before anesthesia was induced with intravenous propofol and maintained with isoflurane. Variables included duration to perform nerve blocks, intraoperative rescue analgesia, recovery score, postoperative pain scores (modified University of Melbourne, Colorado State University and visual analog pain scales), postoperative rescue analgesia-sedation and complications observed. Two-tailed Student t test, Mann-Whitney test, repeated measures analysis of variance, Friedman test and Fisher exact test were used for comparison. Significance was p < 0.05.

RESULTS

Time to perform nerve blocks was [median (range)] 4.3 (2.6-6.1) minutes after aseptic skin preparation. Total fentanyl requirements were 14.2 ± 9 μg kg^-1 and 25.4 ± 10 μg kg^-1 (p = 0.02) and incidence of hypotension (mean arterial pressure < 60 mmHg) was 40% and 80% (p = 0.16) for groups RA and CON, respectively. Six of eight group CON dogs required more intensive treatment for hypotension than group RA dogs. Recovery scores were 1 (1-4) and 2.5 (1-4) for groups RA and CON, respectively (p = 0.04). RA dogs were less likely to require fentanyl rescue analgesia during the postoperative period (p = 0.04).

CONCLUSION AND CLINICAL RELEVANCE

As part of a multimodal analgesia regimen, ultrasound-guided lumbar plexus and sciatic nerve blocks provided greater analgesia and improved recovery quality in dogs during TPLO surgery.

Evaluation of the potential efficacy of an ultrasound-guided adductor canal block technique in dog cadavers

OBJECTIVE

To evaluate an ultrasound-guided technique for adductor canal (AC) block by describing the distribution of methylene blue around the AC, popliteal fossa, saphenous, tibial and common fibular nerves in dog cadavers.

STUDY DESIGN

Prospective experimental trial.

ANIMALS

Ten mixed breed canine cadavers weighing 28.55 ± 3.94 kg.

METHODS

Ultrasound scans of the AC were performed bilaterally in 10 canine cadavers. A high-frequency linear transducer was placed on the long axis of the pectineus muscle and using an in-plane technique, an insulated needle was introduced at a proximal to distal direction into the AC. Methylene blue 0.1% (0.3 mL kg^-1) was administered followed by dissection. The presence of dye over the target nerves for ≥2 cm was considered successful distribution. Three of 10 cadavers were submitted to computed tomography (CT) and one of them to magnetic resonance (MR) evaluation.

RESULTS

Methylene blue reached the AC in 20 (100%) and the popliteal fossa in 17 (85%) pelvic limbs. Staining was successful in the saphenous nerve (4.0 ± 1.57 cm) in 11 (55%) limbs, tibial nerve (2.65 ± 0.8 cm) in six (30%) and common fibular nerve (2.7 ± 0.9 cm) in four (20%). There was no evidence of staining around the motor branches of the femoral nerve. No intraneural or intravascular dye spread was found during dissections. Contrast distribution to the popliteal fossa was observed in three limbs (50%) in CT and in one (50%) MR image.

CONCLUSIONS AND CLINICAL RELEVANCE

Although the tibial and common fibular nerves were not stained as often as the saphenous nerve, dye was encountered throughout the popliteal fossa near the nerves. The AC block may be useful for intra and postoperative analgesia in stifle surgery with minimal femoral motor dysfunction. However, further study is required to confirm its efficacy and safety in vivo.

Comparison of two cold compression therapy protocols after tibial plateau leveling osteotomy in dogs

OBJECTIVE

To evaluate two different protocols of cold compression therapy (CCT) for pain management and functional recovery in dogs undergoing tibial plateau leveling osteotomy (TPLO).

MATERIAL AND METHODS

A total of 27 adult dogs (n = 30 stifles; staged bilateral procedures: n = 3) undergoing routine TPLO were randomly allocated to three groups (n = 10/group). Dogs of group I received CCT once before and immediately after surgery. In dogs of group II CCT was performed postoperatively four times at 6-hour intervals. Dogs of the control group did not receive CCT. Circumference of the stifle joint and the following pain-related parameters were measured by a single blinded observer before surgery and 1, 10 and 42 days after surgery: stifle joint range of motion (ROM), subjective degree of lameness, and score of a modified Glasgow Pain Scale (GPS).

RESULTS

Both CCT groups showed significantly greater ROM and lower GPS scores 24 hours after surgery compared to the control group. Ten days after surgery there was a significantly lower degree of lameness in both CCT groups compared to the control group. Fourty-two days after surgery a significantly greater ROM was observed in both CCT groups compared to the control group. Group II also showed a significant improvement in the degree of lameness and GPS. There were no significant differences in any of the parameters between the two CCT groups at any time point.

CONCLUSION

CCT applied preoperatively and immediately postoperatively showed similar short- and long-term beneficial results compared to a previously established protocol of applying CCT four times postoperatively. This protocol may be more suitable for practical use.

CLINICAL SIGNIFICANCE

The reported data can be used to establish the new protocol of CCT in a clinical surrounding and to support postoperative rehabilitation of the canine patient.

What is the evidence? The issue of verifying correct needle position during epidural anaesthesia in dogs

OBJECTIVES

To review the methods for verifying the needle position while performing epidural anaesthesia in dogs, and to discuss the advantages, disadvantages, usefulness and reliability of each technique in the experimental and clinical research setting.

DATABASES USED

PubMed, Scopus, Google Scholar and the Basel University Library online catalogues; the latter, which was provided by the University of Berne, were used as databases. The results were filtered manually based on the titles and abstracts in order to narrow the field.

CONCLUSIONS

Besides some drawbacks, including the potential side effects of contrast medium injection, which may limit its routine use in clinical patients, epidurography should still be regarded as one of the most reliable techniques to verify needle position in dogs. Ultrasonography, electrical nerve stimulation, loss of resistance and the hanging drop technique are regarded as less invasive than epidurography and, for this reason, their use may be more applicable to clinical patients. However, these methods have been described in only a few published reports, all of which involved a limited number of dogs. Finally, the detection of epidural pressure waves has been investigated more extensively in dogs, and the findings of these studies suggest that this technique may be used to verify epidural needle placement for experimental and clinical research, on condition that all the negative subjects are excluded from the study.

Analgesic and Sedative Effects of Dezocine and Midazolam During Vitrectomy

PURPOSE

To evaluate the analgesic and sedative effectiveness of dezocine and midazolam in vitrectomy.

METHODS

One hundred and sixty patients undergoing vitrectomy were randomized into four groups. The control group was given local anesthetic in retrobulbar nerve block only, while the other three groups received a single dose of 0.1 mg/kg dezocine or/and 0.05 mg/kg midazolam (groups D, M, DM), respectively, at 10 min before retrobulbar block. Mean arterial pressure (MAP), heart rate (HR), and oxygen saturation (SpO₂) were recorded prior to local anesthesia (Tp), at the start of surgery (T0), 5, 15, 30 min during (T1-T3), and at the end of surgery (T4). Pain at T2 and T4 was assessed by Numeric Rating Scale (NRS). Level of sedation at T2 was assessed using the Ramsay scale. Postoperative nausea and vomiting (PONV) events were recorded for 24 h.

RESULTS

Group DM showed a decrease in HR during T0-T4 compared to Tp (p < 0.001). The MAP of all groups decreased significantly at T0 compared to Tp (p < 0.05), but remained unchanged at T1-T4. At T2, all groups have lower pain level than control (p < 0.001), while group DM showed the lowest pain level. At T4, groups D and DM showed a lower pain level than control (p < 0.01). Groups M and DM showed a higher Ramsay score than group C (p < 0.01). Compared with control, group D had a higher PONV rate (p < 0.1). Groups M and DM showed a lower PONV rate than group D (p < 0.0001), and group M had a lower PONV rate than group C (p < 0.01).

CONCLUSION

Combinatory use of dezocine and midazolam in addition to local anesthetic in retrobulbar nerve block can help relief pain and anxiety during vitrectomy and reduce PONV.

Evaluating Femoral-Sciatic Nerve Blocks, Epidural Analgesia, and No Use of Regional Analgesia in Dogs Undergoing Tibia-Plateau-Leveling-Osteotomy

This is a retrospective study evaluating femoral-sciatic nerve blocks (FSBs), epidural analgesia, and non-regional analgesia (NRA) in dogs undergoing tibia-plateau-leveling-osteotomy surgery. Thirty-five records met the criteria for each of the FSB and epidural analgesia groups. Seventeen anesthesia records met the criteria for the NRA or control group. The parameters reported were: isoflurane vaporizer setting, rescue analgesia/anesthesia drugs received, heart rate, systolic blood pressure, and recovery quality (0-4, with 0 being poor and 4 being good). Rescue analgesia-anesthesia during surgery was performed with either fentanyl, ketamine, or propofol. A larger percentage of dogs in the NRA group required rescue analgesia during surgery. The FSB group had a higher recovery quality with median (95% confidence interval of four (±0.3) when compared to two (±0.8) in NRA (p < 0.01). No difference between groups was observed on any other parameter reported. As part of a multimodal analgesia approach for tibia-plateau-leveling-osteotomy surgery, the use of femoral and sciatic nerves blocks with bupivacaine appears to be an alternative technique to help with analgesia and anesthesia during surgery.

Botulinum toxin type A as an adjunct in postoperative pain management in dogs undergoing radical mastectomy

The aim of this randomised placebo-controlled, observer-blinded study was to evaluate the analgesic effects of botulinum toxin type A (BoNT-A) as an adjunct for postoperative pain control in dogs. Sixteen dogs undergoing bilateral radical mastectomy for treatment of mammary tumours were enrolled. Twenty-four hours before surgery, the subjects were distributed into two groups of eight dogs each: 7 iu/kg BoNT-A (BoNT-A) or saline (Control) was administered subcutaneously in each mammary gland. Following sedation with intramuscular 0.03 mg/kg acepromazine and 0.3 mg/kg morphine, anaesthesia was induced intravenously with 4 mg/kg propofol and maintained with isoflurane/O2. Postoperative analgesia was evaluated for 72 hours after extubation using the Visual Analogue Scale (VAS) and modified Glasgow Composite Measure Pain Scale (modified-GCMPS). Rescue analgesia was provided with intramuscular morphine (0.5 mg/kg). Data were analysed using analysis of variance, Tukey's test, Mann-Whitney U test and Friedman test (P<0.05). The pain scores were significantly lower in the BoNT-A than in the Control from 8 hours to 60 hours and from 12 hours to 60 hours after extubation, based on the VAS and modified-GCMPS, respectively. Rescue analgesia was required by significantly more dogs in the Control (7/8) compared with the BoNT-A (2/8) (P=0.022). Pre-emptive BoNT-A appears to be effective as an adjuvant for postoperative pain management in dogs undergoing bilateral radical mastectomy.

Use of a perineural coiled catheter at the sciatic nerve in dogs after tibial plateau levelling osteotomy - preliminary observations

The analgesic effects of peripheral nerve blocks can be prolonged with the placement of perineural catheters allowing repeated injections of local anaesthetics in humans. The objectives of this study were to evaluate the clinical suitability of a perineural coiled catheter (PCC) at the sciatic nerve and to evaluate pain during the early post-operative period in dogs after tibial plateau levelling osteotomy. Pre-operatively, a combined block of the sciatic and the femoral nerves was performed under sonographic guidance (ropivacaine 0.5%; 0.3 mL kg^-1 per nerve). Thereafter, a PCC was placed near the sciatic nerve. Carprofen (4 mg kg^-1 intravenously) was administered at the end of anaesthesia. After surgery, all dogs were randomly assigned to receive four injections of ropivacaine (group R; 0.25%, 0.3 mL kg^-1) or NaCl 0.9% (group C; 0.3 mL kg^-1) every 6 h through the PCC. Pain was assessed by use of a visual analogue scale (VAS) and a multi-dimensional pain score (4Avet) before surgery (T-1), for 390 min (T0, T30, T60, T120, T180, T240, T300, T360 and T390) as well as 1 day after surgery (Day 1). Methadone (0.1 mg kg^-1) was administered each time the VAS was ≥40 mm or the 4Avet was ≥5. At T390 dogs received buprenorphine (0.02 mg kg^-1). Data were compared using Mann-Whitney rank sum tests and repeated measures analysis of variance. Regardless of group allocation, 55% of dogs required methadone. VAS was significantly lower at T390 (P = 0.003), and at Day 1 (P = 0.002) and so was 4Avet at Day 1 (P = 0.012) in group R than in group C. Bleeding occurred in one dog at PCC placement and PCC dislodged six times of 47 PCCs placed. Minor complications occurred with PCC but allowed four repeated administrations of ropivacaine or saline over 24 h in 91.5% of the cases.

Postoperative comparison of four perioperative analgesia protocols in dogs undergoing stifle joint surgery

OBJECTIVE

To compare 4 analgesic protocols in dogs undergoing stifle joint surgery.

DESIGN

Randomized, blinded, prospective clinical trial. Animals-48 client-owned dogs that underwent stifle joint surgery.

PROCEDURES

Dogs undergoing tibial plateau leveling osteotomy were randomly assigned to receive a constant rate infusion of a combination of morphine, lidocaine, and ketamine; a lumbosacral epidural with morphine and ropivacaine; both treatments (ie, constant rate infusion and lumbosacral epidural); or only IM premedication with morphine. Indices of cardiorespiratory function and isoflurane requirement were recorded at 5-minute intervals during anesthesia. A validated sedation scoring system and the modified Glasgow composite measure pain score were used to assess comfort and sedation after surgery and anesthesia once the swallowing reflex returned and a body temperature of ≥ 36.7°C (98.1°F) was attained. Pain and sedation scores were acquired at 60-minute intervals for 4 hours, then at 4-hour intervals for 24 hours. Dogs with a postoperative pain score > 5 of 24 were given morphine as rescue analgesia.

RESULTS

No differences in heart rate, respiratory rate, systolic arterial blood pressure, end-tidal Pco2, end-tidal isoflurane concentration, and vaporizer setting were detected among groups. No differences in pain score, sedation score, rescue analgesia requirement, or time to first rescue analgesia after surgery were detected.

CONCLUSIONS AND CLINICAL RELEVANCE

Pain scores were similar among groups, and all 4 groups had similar rescue analgesia requirements and similar times to first administration of rescue analgesia. All 4 analgesic protocols provided acceptable analgesia for 24 hours after stifle joint surgery.

Analgesic comparison of systemic lidocaine, morphine or lidocaine plus morphine infusion in dogs undergoing fracture repair

PURPOSE

To compare the postoperative analgesic effects of lidocaine, morphine and lidocaine plus morphine administered by constant rate infusion (CRI) and analyzing their effects on opioid requirements after orthopedic surgery in dogs.

METHODS

Twenty-four dogs underwent fracture repairs were premedicated with IM acepromazine (0.05 mg/kg) combined with morphine (0.3mg/kg). Anesthesia was induced with IV propofol (4 to 5 mg/ kg) and maintained with isoflurane. The dogs were randomly assigned to 3 groups and administered a CRI IV of lidocaine (T-L), morphine (T-M) or lidocaine plus morphine (T-LM) at the same doses. Postoperative analgesia was assessed for 24 hours using a Visual Analog Scale (VAS) and the Glasgow Composite Pain Scale (GCPS). Rescue analgesia was performed if the evaluation score exceeded 50% of the VAS and/or 33% of the GCPS.

RESULTS

The pain score and postoperative opioid requirements did not differ among the treatments. Rescue analgesia was administered to 1/8 dogs in the T-M and T-LM, and to 3/8 dogs in the T-L.

CONCLUSION

Lidocaine, morphine or lidocaine/morphine CRI may be efficacious techniques for pain management in the first 24 hours post-surgery. However, the two drugs administered together did not reduce the postoperative opioid requirement in dogs undergoing fracture repair. Key words: Anesthesia. Analgesics. Analgesics, Opioid. Lidocaine. Morphine. Dogs.

Limitations of the use of pressure waves to verify correct epidural needle position in dogs

The use of pressure waves to confirm the correct position of the epidural needle has been described in several domestic species and proposed as a valid alternative to standard methods, namely, control radiographic exam and fluoroscopy. The object of this retrospective clinical study was to evaluate the sensitivity of the epidural pressure waves as a test to verify the correct needle placement in the epidural space in dogs, in order to determine whether this technique could be useful not only in the clinical setting but also when certain knowledge of needle's tip position is required, for instance when performing clinical research focusing on epidural anaesthesia. Of the 54 client-owned dogs undergoing elective surgeries and enrolled in this retrospective study, only 45% showed epidural pressure waves before and after epidural injection. Twenty-six percent of the animals showed epidural pressure waves only after the injection, whereas 29% of the dogs showed epidural pressure waves neither before nor after injection and were defined as false negatives. Our results show that the epidural pressure wave technique to verify epidural needle position lacks sensitivity, resulting in many false negatives. As a consequence, the applicability of this technique is limited to situations in which precise, exact knowledge of the needle's tip position is not mandatory.

Preoperative administration of intramuscular dezocine reduces postoperative pain for laparoscopic cholecystectomy

Postoperative pain is the most common complaint after laparoscopic cholecystectomy. This study was carried out to evaluate whether preoperative administration of intramuscular dezocine can provide postoperative analgesia and reduce postoperative opioid consumption in patients undergoing laparoscopic cholecystectomy. Patients (ASA I or II) scheduled for laparoscopic cholecystectomy were randomly assigned into intramuscular dezocine group (group 1) or intramuscular normal saline group (group 2). Dezocine and equal volume normal saline were administered intramuscularly 10 min before the induction of anesthesia. After operation, the severity of postoperative pain, postoperative fentanyl requirement, incidence and severity of side-effects were assessed. Postoperative pain and postoperative patient-controlled fentanyl consumption were reduced significantly in group 1 compared with group 2. The incidence and severity of side effects were similar between the two groups. Preoperative single-dose administration of intramuscular dezocine 0.1 mg/kg was effective in reducing postoperative pain and postoperative patient-controlled fentanyl requirement in patients undergoing laparoscopic cholecystectomy.

Intra-articular morphine, bupivacaine or no treatment for postoperative analgesia following unilateral elbow joint arthroscopy

OBJECTIVES

To compare intra-articular morphine or bupivacaine against no treatment following unilateral elbow joint arthroscopy using force plate analysis and pain scoring.

METHODS

Thirty-one dogs were randomly allocated to receive 0·1 mg/kg intra-articular morphine, 0·5 mg/kg bupivacaine or no treatment following elbow arthroscopy. Force plate analysis, pain scoring and kinematic evaluation were performed before anaesthesia, 4 and 24 hours after surgery. Peak vertical force index, symmetry index, rate of loading, rate of unloading, stance time and range of motion were obtained from gait analysis. Pain scoring was performed every 4 hours and interventional analgesia (0·3 mg/kg methadone) was administered if necessary.

RESULTS

Of 29 dogs analysed, peak vertical force index (P<0·001), symmetry index (P=0·01) and rate of unloading (P=0·01) decreased significantly over time in each group; however, this was not affected by treatment. No significant differences were observed in stance time or rate of loading over time. Kinematic (range of motion) evaluation was not complete for all dogs. Pain scores increased significantly at both time points postoperatively in the no treatment group (P=0·007) and in morphine-treated dogs at 4 hours compared to baseline (P=0·03). For intra-articular bupivacaine significant increases in pain scores were not detected (P=0·28).

CLINICAL SIGNIFICANCE

No benefit to intra-articular bupivacaine or morphine was detected using peak vertical force index from force plate analysis. Bupivacaine prevented increases in pain scores at both time points as did morphine at the 24-hour evaluation, compared to no treatment.

Effect of cold compression therapy on postoperative pain, swelling, range of motion, and lameness after tibial plateau leveling osteotomy in dogs

OBJECTIVE

To evaluate the effect of cold compression therapy (CCT) on postoperative pain, lameness, range of motion of the stifle joint, and swelling following tibial plateau leveling osteotomy (TPLO) in dogs.

DESIGN

Randomized, blinded, placebo-controlled clinical trial.

ANIMALS

34 client-owned dogs with unilateral deficiency of a cranial cruciate ligament undergoing TPLO.

PROCEDURES

Dogs were assigned to 2 groups. Group 1 (n = 17 dogs) received CCT in the 24-hour period following TPLO. Group 2 (n = 17 dogs) received no CCT. Degree of lameness, range of motion, and circumference of the stifle joint were measured before surgery and 1,14, and 28 days after surgery. A modified composite Glasgow pain scale, visual analogue scale, and pain threshold score were used to evaluate signs of pain before surgery and 1,14, and 28 days after surgery. Logistic regression and linear regression analysis were used to compare the measured variables.

RESULTS

No complications were observed, and all dogs tolerated CCT. Use of CCT resulted in lower values for the visual analogue scale and Glasgow pain scale and lower pain threshold scores; lower lameness scores; less swelling; and an increased range of motion 24 hours after surgery. At 14 days after surgery, there were no significant differences between groups. At 28 days after surgery, too few data sets were available for comparison.

CONCLUSIONS AND CLINICAL RELEVANCE

CCT decreased signs of pain, swelling, and lameness and increased stifle joint range of motion in dogs during the first 24 hours after TPLO.

Antinociceptive activity of pre- versus post-operative intra-articular bupivacaine in goats undergoing stifle arthrotomy

OBJECTIVE

To evaluate the peri-operative analgesic efficacy of intra-articular bupivacaine administered before or after stifle arthrotomy.

STUDY DESIGN

Prospective, randomized, blind, placebo-controlled experimental trial.

ANIMALS

Thirty-nine healthy goats.

METHODS

The goats were allocated randomly to one of three intra-articular treatment groups: group PRE (bupivacaine before and saline after surgery), group POST (saline before and bupivacaine after surgery) and group CON (saline before and after surgery). Anaesthesia was maintained with a constant end-tidal sevoflurane of 2.5%. Intra-operatively heart rate (HR), respiratory rate and mean arterial blood pressure (MAP) after critical surgical events (CSE) were recorded and compared with pre-incision values. Propofol requirements to maintain surgical anaesthesia were recorded. Flunixin was administered for 5 days. Post-operative pain assessment at 20 minutes, 2 hours, 4 hours after recovery and on day 2 and 3 included a multidimensional pain score (MPS), a lameness score and mechanical nociceptive threshold (MNT) testing. Rescue analgesia consisted of systemic opioids. Data were analysed using Kruskal-Wallis, Mann-Whitney, Friedman or chi-square tests as appropriate.

RESULTS

Intra-operatively, group PRE had lower HR and MAP at several CSEs than groups POST/CON and required less propofol [0 mg kg(-1) (0-0 mg kg(-1))] than group POST/CON [0.3 mg kg(-1) (0-0.6 mg kg(-1))]. Post-operatively, group POST had significantly higher peri-articular MNTs than groups PRE and CON up to 4 hours after recovery. No treatment effect was detected for MPS, lameness scores and rescue analgesic consumption at any time point.

CONCLUSIONS AND CLINICAL RELEVANCE

Pre-operative intra-articular bupivacaine provided notable intra-operative analgesia in goats undergoing stifle arthrotomy but did not reduce post-operative pain. Post-operative intra-articular bupivacaine provided a short lasting reduction of peri-articular hyperalgesia without affecting the requirements for systemic analgesia. Multimodal perioperative pain therapy is recommended to provide adequate analgesia for stifle arthrotomy in goats.

Evaluation of chondrocyte death in canine osteochondral explants exposed to a 0.5% solution of bupivacaine

OBJECTIVE

To evaluate chondrocyte death in canine articular cartilage exposed in vitro to bupivacaine with and without methylparaben and to compare viability for cartilage with intact or mechanically debrided surfaces.

SAMPLE POPULATION

Both glenohumeral joints from 10 adult canine cadavers.

PROCEDURES

10 osteochondral cores were harvested from each of the 20 humeral heads; synovium and 1 core from each joint were examined to verify joint health, and the other 9 cores were exposed to canine chondrocyte culture medium (CCCM), a 0.5% solution of bupivacaine, or 0.5% solution of bupivacaine with methylparaben for 5, 15, or 30 minutes.

RESULTS

For the superficial zone of surface-intact chondrocytes, bupivacaine with methylparaben caused a significantly higher percentage of chondrocyte death at 5 minutes (47.7%) than did bupivacaine (23.6%) or CCCM (25.4%). Bupivacaine (53.8%) and bupivacaine with methylparaben (62.5%) caused a significantly higher percentage of chondrocyte death at 30 minutes than did CCCM (20.0%). For the superficial zone of chondrocytes with debrided surfaces, bupivacaine with methylparaben caused a significantly higher percentage of chondrocyte death at 30 minutes (59%) than it did at 5 minutes (37.7%). Bupivacaine with methylparaben caused a significantly higher percentage of chondrocyte death at 30 minutes (59.0%) than did CCCM (28.9%). For middle and deep zones of chondrocytes, treatment solution and surface debridement had minimal effects on percentage of chondrocyte death.

CONCLUSIONS AND CLINICAL RELEVANCE

Bupivacaine and bupivacaine with methylparaben were cytotoxic to canine articular chondrocytes in vitro. Intra-articular administration of bupivacaine is not recommended for clinical use until additional studies are conducted.

Anesthetic considerations in orthopedic patients with or without trauma

Anesthetic management of orthopedic patients could vary from normal routine management to more challenging critical management depending on the state in which the patient is presented. Multimodal pain management strategies incorporating opioids, which are the mainstay drugs for pain management, along with adjunctive drugs like local anesthetics (eg, lidocaine), dissociative anesthetics (eg, ketamine), and alpha-2 agonists (eg, dexmedetomidine), could improve overall patient comfort and help prevent establishment of chronic pain pathways. Also, use of local nerve blocks can prevent nociception right at the point of origin. Orthopedic patients with multiple organ traumas like head injuries, spinal injuries, pulmonary fat embolism, compartment syndrome, or thoracic injuries are high-risk patients in which any life-threatening organ pathology should be addressed before the patient is put under general anesthesia. Interactions of various drugs like antibiotics and neuromuscular blocking agents used in the perioperative period in orthopedic patients should warrant a careful consideration with respect to their interactions with each other and other anesthetic drugs used.

Comparison between analgesic effects of buprenorphine, carprofen, and buprenorphine with carprofen for canine ovariohysterectomy

OBJECTIVE

To compare the analgesic effects of buprenorphine, carprofen, and their combination in dogs undergoing ovariohysterectomy.

STUDY DESIGN

Prospective, randomized blinded clinical study.

ANIMALS

60 dogs.

METHODS

Treatments were buprenorphine 0.02 mg kg(-1), intramuscularly (IM) (group B); carprofen 4 mg kg(-1), subcutaneously (SC) (group C); or a combination of both (group CB). Anesthesia was induced with propofol and maintained with isoflurane. A Dynamic Interactive Visual Analog Scale (DIVAS, 0-100 mm) and the Glasgow Composite Pain Scale (GCMPS, 0-24) were used to evaluate comfort and sedation at baseline, 2, 4, 6, and 24 hours after extubation. Rescue analgesia was provided with buprenorphine (0.02 mg kg(-1)). Wound swelling measurements (WM) and a visual inflammation score (VIS) of the incision were made after surgery and 2, 4, 6, and 24 hours later. p < 0.05 was considered significant.

RESULTS

Group C required more propofol (5.0 +/- 1.4 mg kg(-1)) compared with B (3.3 +/- 1.1 mg kg(-1)) and CB (3.2 +/- 0.7 mg kg(-1)); respectively, p = 0.0002 and 0.0001. Rescue analgesia was required in nine dogs. B had a higher GCMPS and DIVAS III score at 6 hours (2.6 +/- 2.5) and (23 +/- 22.5 mm) compared with C (1.0 +/- 1.3, 6 +/- 7.3 mm) and CB (1.5 +/- 1.4, 8 +/- 10.7 mm); respectively, p = 0.02 and 0.006. Group C had a lower sedation score at 2 hours (43 +/- 23.6 mm) compared with B (68 +/- 32.1 mm) and BC (69 +/- 22.1 mm); respectively, p = 0.03 and 0.004. Group B had a higher WM score at 2 hours (3 +/- 0.8 mm) compared with C (2 +/- 0.6 mm) p = 0.01 and at 6 hours (3 +/- 1 mm) compared with C (2 +/- 0.8 mm) and CB (2 +/- 0.8 mm); respectively, p = 0.01 and 0.008. VIS was not different between groups.

CONCLUSION AND CLINICAL RELEVANCE

All treatments provided satisfactory analgesia for the first 6 hours and at 24 hours. C and CB pain score and WS were superior to B at 6 hours. No superior analgesic effect was noted when the drugs were combined.

A comparison of tepoxalin-buprenorphine combination and buprenorphine for postoperative analgesia in dogs: a clinical study

The present study compares the analgesic effect of a tepoxalin-buprenorphine combination to that of buprenorphine alone in the 24 h peri-operative period in 20 dogs undergoing cranial cruciate ligament repair, which were randomly assigned to the two treatment protocols (n = 10). Additionally, possible side effects induced by tepoxalin were investigated. Analgesia was compared using a visual analogue scale (VAS) and a multifactorial pain scale (MFPS), by an anaesthetist blinded from treatment. Analysis of the overall VAS-scores showed a significant decrease over time in both treatment groups. The decrease in the two groups was not significantly different from each other. No significant differences were found between the MFPS-scores of both protocols. Potential side effects of tepoxalin were investigated by venous blood sampling before premedication and 24 h after extubation, a buccal mucosal bleeding time test and recording of vomiting, diarrhoea and adverse effects at the surgical site. Analysis of the blood parameters showed that fibrinogen levels were overall higher 24 h after surgery in both protocols, but were significantly more elevated in the tepoxalin group. No significant differences were found for the other blood parameters. Statistically, tepoxalin failed to improve analgesia induced by buprenorphine. There was no convincing evidence that the administration of tepoxalin was not associated with gastrointestinal side effects. There were no significant adverse effects on renal function and primary haemostasis.