Postoperative pain in dogs undergoing either laparoscopic or open ovariectomy

A prospective, quasi-experimental, clinical trial was performed to assess acute postoperative pain in healthy female dogs following elective ovariectomy by either laparoscopy (n=13) or laparotomy (n=14). Pain was assessed by both a veterinarian at the hospital, and by the owner once the patient was discharged. The Spanish version of the short form of the Glasgow Composite Measuring Pain Scale (CMPS-SF) was used. Pain scores were assessed by the veterinarian preoperatively and at 1, 2, 4, and 6 h after extubation, whilst owner-assessed scores were performed preoperatively and at postoperative days 0, 1, 2, 3, 5 and 7. Data were compared with Mann-Whitney-U test. Veterinarian-assessed CMPS-SF scores were different between both groups at all postoperative times but not at baseline, being below 6/24 in all dogs in the laparoscopy group, but equal to or greater than 6/24 in the laparotomy group at 1 h (n=12), and 4 h (n=4) (P<0.001 and P=0.029, respectively). There were also differences in pain scores between both groups at 2 h (P=0.012) and 6 h (P=0.007), being below 6/24 in all of them. However, there were no differences in owner assessments between groups. In conclusion, ovariectomy performed by laparoscopy induced lower pain scores that were below the pain threshold set by the CMPS-SF during the first 6 h postoperatively. After discharge, and up to one week later, ongoing owner-assessed scores suggest no pain was induced with neither of the techniques. Owners were proactive allowing real-time pain assessment to be reported. The development and validation of instruments for acute pain assessment by owners is warranted, as these tools are currently lacking.

Effects and mechanisms of perioperative medications on the hypothalamic pituitary adrenal response to surgical injury: A narrative review

The adrenal gland is a vital endocrine organ, and adrenal steroid synthesis and secretion are closely regulated by the hypothalamic-pituitary-adrenal (HPA) axis in response to various stimuli. Surgery or trauma can activate the HPA axis and induce the secretion of cortisol. Different cortisol responses vary with the grade of surgery. Perioperative medications have the potential to decrease the cortisol level in the body, and both excessive and insufficient cortisol levels after surgery are disadvantageous. The effect of perioperative medications on the HPA response to surgery can be divided into three levels: "adrenal insufficiency (AI)", "stress response inhibition", and "uncertainty". The clinical presentation of AI includes fatigue, nausea, vomiting, abdominal pain, muscle cramps, hypotension, hypovolemic shock and prerenal failure, which may result in fatal consequences. Stress response inhibition can reduce postoperative complications, such as pain and cognitive dysfunction. This is protective to patients during perioperative and postoperative periods. The aim of the present review is to shed light on current evidence regarding the exact effects and mechanisms of perioperative medications on the HPA response to surgical injury and provide the applicable guidance on clinical anesthesia.

Tramadol vs. Lidocaine Administered Intraperitoneally and in Incisional Lines for the Intraoperative and Postoperative Pain Management of Romifidine-Telazol-Anesthetized Swine Undergoing Umbilical Hernia Repair

The aim of the study was to compare the analgesic efficacy of tramadol and lidocaine for local anesthesia during umbilical hernia repair in swine. The study was performed on 66 large white crossbred swine. The swine received a mixture of tiletamine/zolazepam at 5 mg/kg and romifidine at 80 µg/kg, administered intramuscularly. Then, they were divided into three groups (n = 22) that received different treatments with lidocaine at 4 mg/kg and tramadol at 4 mg/kg. The LL group received lidocaine both by infiltration of the surgical planes and intraperitoneally. The LT group received lidocaine by infiltration of the surgical planes and tramadol intraperitoneally. The TT group received tramadol both by infiltration of the surgical planes and intraperitoneally. In all groups, the infiltration of the surgical planes into the umbilical region involved both the skin and muscle planes. Heart rate, noninvasive arterial blood pressure, and respiratory frequency were recorded during surgery. The response to the surgical stimulus was evaluated using a cumulative pain scale (the cut-off point for rescue analgesia was set to 10). Postoperative pain was assessed using the UNESP-Botucatu pig composite acute pain scale (the cut-off point was set to 4). The trend of physiological variables was adequate for patients under anesthesia. No subject required intraoperative and postoperative rescue analgesia. Tramadol could therefore be used for pain management in livestock.

Evaluation of the Analgesic Efficacy of Undiluted Intraperitoneal and Incisional Ropivacaine for Postoperative Analgesia in Dogs after Major Abdominal Surgery

Recommendations for intraperitoneal (IP) and incisional (INC) administration of local anaesthetics after visceral surgery exist, but evidence is scarce. This prospective, randomized, blinded, controlled, clinical trial compared postoperative pain in dogs undergoing major abdominal surgery. Sixteen client-owned dogs were anaesthetized with a standardized balanced protocol including opioids and received either 2 mg/kg ropivacaine IP (0.27 mL/kg) and a 1 mg/kg INC splash (0.13 mL/kg) or equal volumes of saline. Influence of the treatment on heart rate (HR) and postoperative pain was assessed using the Short Form of the Glasgow Composite Pain Scale (GCPS-SF), a dynamic interactive visual analogue scale (DIVAS) and mechanical nociceptive threshold testing (MNT). Data was tested with mixed ordinal regression and log linear mixed models for 0.5, 1, 2, 3, 4, 6, 8, 10 and 12 h after extubation. Rescue analgesia was given to 3/8 dogs after ropivacaine and 0/8 dogs after saline. GCPS-SF and MNT were not different between groups. DIVAS was slightly higher after ropivacaine (odds increased by 5.44 (confidence interval (CI) 1.17-9.96, p = 0.012)), and HR after ropivacaine was 0.76 * that after saline (CI 0.61-0.96, p = 0.02) with no effect of time (p = 0.1). Undiluted ropivacaine IP and INC was not beneficial for postoperative analgesia.

2022 AAHA Pain Management Guidelines for Dogs and Cats

These updated guidelines present a practical and logical approach to the assessment and management of acute and chronic pain in canine and feline patients. Recognizing pain is fundamental to successful treatment, and diagnostic guides and algorithms are included for assessment of both acute and chronic pain. Particularly for chronic pain, capturing owner evaluation is important, and pain-assessment instruments for pet owners are described. Expert consensus emphasizes proactive, preemptive pain management rather than a reactive, "damage control" approach. The guidelines discuss treatment options centered on preemptive, multimodal analgesic therapies. There is an extensive variety of pharmacologic and nonpharmacologic therapeutic options for the management of acute and chronic pain in cats and dogs. The guidelines include a tiered decision tree that prioritizes the use of the most efficacious therapeutic modalities for the treatment of acute and chronic pain.

Evaluation of intraperitoneal administration of morphine on post-operative pain management after ovariohysterectomy in dogs

The present prospective randomized experimental study was designed to assess pain control with intraperitoneal morphine following ovariohysterectomy in dogs. A group of 12 mixed breed female dogs, aged 1-2 years, weighing 19.95 ± 0.95 kg were included. Forty minutes after sedation with 0.05 mg/kg intramuscular acepromazine 1%, anaesthesia was induced with propofol (4 mg/kg). The dogs were connected to the inhalation anaesthesia circuit using isoflurane. Ovariohysterectomy was performed, and before the closure of linea alba, the animals received intraperitoneal morphine (0.5 mg/kg) (in group M) and saline (0.2 ml/kg) (in group S). No significant difference was detected in total protein and glucose levels between the groups, while the cortisol level in group M was significantly lower than group S 1, 3 and 6 h after surgery. Furthermore, the comparison of the rectal temperature, heart rates and respiratory rates showed no major differences. Additionally, no significant alterations were detected between the groups considering the changes in the pain scores with simple descriptive score, Glasgow, University of Melbourne pain scale, sedation status and Sammarco methods. Finally, three cases in group S and two cases in group M were given an intramuscular analgesic rescue dose of morphine. Although a significant decline was observed in cortisol levels following intraperitoneal morphine administration, there were no beneficial changes in the efficiency of post-operative analgesia in status and clinical signs compared to the control group. Further studies are required to investigate intraperitoneal morphine effectiveness in post-operative pain management.

Preperitoneal ropivacaine infusion versus epidural ropivacaine-morphine for postoperative analgesia in dogs undergoing ovariohysterectomy: a randomized clinical trial

OBJECTIVE

To assess the effect of continuous wound infusion (CWI) with preperitoneal ropivacaine on postoperative analgesia and compare it with the epidural administration of ropivacaine and morphine in bitches undergoing ovariohysterectomy.

STUDY DESIGN

A parallel, randomized, clinical, prospective and nonblinded study.

ANIMALS

A group of 38 Greyhound bitches.

METHODS

In the catheter group (CathG), CWI with ropivacaine 1% (1 mg kg^-1 + 0.8 mg kg^-1 hour^-1) was applied to the preperitoneal space over the surgical incision. In the epidural group (EpiG), ropivacaine 0.5% (1.3 mg kg^-1) and morphine (0.1 mg kg^-1) were epidurally administered. Occipital-coccygeal length was used to calculate the volume for the epidural. Pain was scored using a dynamic interactive visual analogue scale (DIVAS) and Glasgow composite measure pain scale-short form (CMPS-SF) before anaesthesia and at 2, 4, 6, 18, 21 and 24 hours after extubation. Incisional sensitivity using a dynamometer (MWTs-incision) was evaluated simultaneously. Plasma ropivacaine and cortisol concentrations, degree of sedation, motor blockade and response to interdigital clamping were measured or assessed. A two-way mixed analysis of variance and a Mann-Whitney U test were used to analyse data; p < 0.05.

RESULTS

No differences were detected in the DIVAS (p = 0.301), CMPS-SF (p = 0.600) scores, MWTs-incision measurements (p = 0.257) and cortisol values (p = 0.878) between the groups. Rescue analgesia was required in two dogs, one in each group, at 2 hours. Sedation, motor blockade and negative response to interdigital clamping were detected in EpiG at 2, 4 and 6 hours. Mean plasma ropivacaine values were higher in CathG (0.475 ± 0.164 ng mL^-1) than in EpiG (0.184 ± 0.213 ng mL^-1; p = 0.001).

CONCLUSION AND CLINICAL RELEVANCE

Compared with epidural ropivacaine and morphine, CWI with preperitoneal ropivacaine is an effective analgesic technique for postoperative pain management in bitches undergoing ovariohysterectomy without motor blockade.

Reasons for Exclusion of Apparently Healthy Mature Adult and Senior Dogs From a Clinical Trial

Background: Interventional clinical trials intended to maintain health in aging dogs are unusual and require particular attention to exclusion criteria.

Objectives: To describe reasons for exclusion when a mature adult and senior canine population with normal health status was sought.

Animals: Fifty six companion dogs nominated for a randomized controlled trial (RCT).

Procedures: Exclusions occurred within Stage 1 (S1): owner-provided survey information; Stage 2 (S2): medical records review; and Stage 3 (S3): screening examination and within Owner, Dog, or Other factor categories.

Results: Of 56 nominated dogs, 39 were excluded at S1 (n = 19), S2 (n = 5), and S3 (n = 15), respectively. Dogs were excluded for Owner (n = 4), Dog (n = 27), Other (n = 6), and concurrent (Owner + Dog; n = 2) factors. The most common exclusion period was S1 (n = 19), with weight outside the target range being the most common exclusion factor in that stage (n = 10). Heart murmurs were the second most common exclusion factor (S1: n = 1; S3: n = 5); suspected or confirmed systemic illness was third most common (S1: n = 2; S2: n = 3; S3: n = 2). Among dogs who passed S1 and S2 screening (n = 32), 15 dogs (48%) were excluded at S3, for heart murmur > grade II/VI (n = 5), cardiac arrhythmias (n = 2), and clinicopathologic abnormalities (n = 2).

Conclusions and Clinical Relevance: Dogs nominated for a clinical trial for healthy mature adult and senior dogs were excluded for size, previous diagnoses, and newly discovered cardiac abnormalities. For future interventions in mature adult and senior dogs of normal health status, it is important to define expected age-related abnormalities to ensure that meaningful exclusion criteria are used.

Intraperitoneal administration of lidocaine or tramadol alone or in combination on postoperative pain after ovariohysterectomy in dogs

The present prospective randomized experimental study aimed to assess the intraperitoneal (ip) administration of lidocaine or tramadol, alone or in combination, on postoperative pain management following ovariohysterectomy in dogs. Eighteen healthy female mixed‐breed dogs, aged 1–2 years, weighed 16.7 ± 3.8 kg, were used. Animals were sedated with acepromazine (0.1 mg/kg, intramuscular). Forty minutes later, anaesthesia was induced through intravenous titration with diazepam (0.5 mg/kg) and ketamine (10 mg/kg) and maintained with isoflurane 1.5%. Afterwards, ovariohysterectomy was performed, and prior to the closure of the linea alba, animals received lidocaine containing epinephrine (8.8 mg/kg, ip) in group L, tramadol (4 mg/kg, ip) in group T and lidocaine containing epinephrine (8.8 mg/kg, ip) plus tramadol (4 mg/kg, ip) in the LT group. Cortisol, vital signs and pain scoring systems were evaluated at different time points. Vital signs did not change among the groups. Cortisol level in the LT group significantly decreased compared to the L and T groups one, three and six hours after surgery. Pain scores also did not change among the groups based on Sammarco and Simple descriptive (SDS) scoring method. However, pain scores in the LT group were higher than the two other groups according to the University of Melbourne pain scale (UMPS) and the short form of Glasgow pain scale (CMPS‐SF). According to the obtained results, the combination of lidocaine and tramadol seemed to be able to provide better analgesia compared with their separate administration. Therefore, combined intraperitoneal administration of lidocaine (8.8 mg/kg) and tramadol (4 mg/kg) with a final volume of (0.2 ml/kg) following ovariohysterectomy is recommended.

Cross-sectional survey of anaesthesia and analgesia protocols used to perform routine canine and feline ovariohysterectomies

OBJECTIVE

To collect baseline descriptive data on the anaesthesia and analgesia protocols used by New Zealand veterinarians in first-opinion practice when performing routine canine and feline ovariohysterectomies.

STUDY DESIGN

Cross-sectional survey.

ANIMALS

Not applicable.

METHODS

An online survey was conducted asking respondents for: 1) preoperative patient assessment; 2) preanaesthetic medication and induction drugs used; 3) anaesthesia maintenance drug choices and monitoring equipment used; and 4) postoperative analgesia drug selections and monitoring for ovariohysterectomy performed in healthy adult dogs and cats.

RESULTS

The survey was completed by 472 veterinarians, of whom 282 provided responses for canine ovariohysterectomy and 361 provided responses for feline ovariohysterectomy. Approximately 23% of canine ovariohysterectomies and 13% of feline ovariohysterectomies had preanaesthetic bloodwork performed. There were 74 unique premedication/induction drug combinations reported for canine ovariohysterectomies and 94 for feline ovariohysterectomies. The most commonly used drug combinations were acepromazine, morphine ± propofol and butorphanol, ketamine and medetomidine for canine and feline ovariohysterectomies respectively. Most animals were intubated, and anaesthesia was maintained with isoflurane in oxygen. Use of intravenous catheters, fluid administration, heat support, and monitoring equipment varied. There were 41 unique postoperative analgesia drug combinations reported for canine ovariohysterectomies and 20 for feline ovariohysterectomies. Canine ovariohysterectomies were most commonly administered injectable opioids on the day of surgery followed by 3 days of oral non-steroidal anti-inflammatory drugs (NSAIDs), whereas feline ovariohysterectomies were usually administered a single injection of an opioid or NSAID or both on the day of surgery. Most animals were seen within 7-10 days for re-examination and/or suture removal.

CONCLUSIONS AND CLINICAL RELEVANCE

Veterinarians use a wide range of anaesthesia and analgesia protocols for routine ovariohysterectomies. Further research is needed comparing the safety and efficacy of commonly used protocols to determine whether there are opportunities to improve the level of patient welfare.

Addition of magnesium sulfate to intraperitoneal ropivacaine for perioperative analgesia in canine ovariohysterectomy

Magnesium may be used as an adjunctive analgesic for perioperative pain management because of its antinociceptive properties. This study investigated the analgesic efficacy of intraperitoneal ropivacaine combined with magnesium sulfate in canine ovariohysterectomy. Forty-five dogs sedated with acepromazine/meperidine and anesthetized with propofol/isoflurane were randomly distributed into three treatments, administered intraperitoneally (n = 15 per group): saline solution (group S), 0.25% ropivacaine (3 mg/kg) alone (group R), or in combination with magnesium sulfate (20 mg/kg, group R-Mg). Intravenous fentanyl was given to control cardiovascular responses to surgical stimulation. Postoperative pain was assessed using an Interactive Visual Analog Scale (IVAS), the short form of the Glasgow Composite Pain Scale, and mechanical nociceptive thresholds. Morphine/meloxicam was administered as rescue analgesia. Intraoperatively, the R-Mg group required less fentanyl (p = .02) and exhibited higher incidence of hypotension (systolic arterial pressure <90 mm Hg, p = .006) compared with the S group. Lower IVAS pain scores were recorded during the first hour in the R-Mg group than the other groups (p = .007-.045). Postoperative rescue analgesia did not differ between groups. Intraperitoneal magnesium sulfate administration, in spite of decreasing intraoperative opioid requirements, increased the incidence of hypotension with minimal evidence of postoperative analgesic benefits.

Comparison of intraperitoneal ropivacaine and ropivacaine-dexmedetomidine for postoperative analgesia in cats undergoing ovariohysterectomy

OBJECTIVE

To investigate the intraperitoneal (IP) administration of ropivacaine or ropivacaine-dexmedetomidine for postoperative analgesia in cats undergoing ovariohysterectomy.

STUDY DESIGN

Prospective, randomized, blinded, positively controlled clinical study.

ANIMALS

A total of 45 client-owned cats were enrolled.

METHODS

The cats were administered intramuscular (IM) meperidine (6 mg kg^-1) and acepromazine (0.05 mg kg^-1). Anesthesia was induced with propofol and maintained with isoflurane. Meloxicam (0.2 mg kg^-1) was administered subcutaneously in all cats after intubation. After the abdominal incision, the cats were administered one of three treatments (15 cats in each treatment): IP instillation of 0.9% saline solution (group Control), 0.25% ropivacaine (1 mg kg^-1, group ROP) or ropivacaine and dexmedetomidine (4 μg kg^-1, group ROP-DEX). During anesthesia, heart rate (HR), electrocardiography, noninvasive systolic arterial pressure (SAP) and respiratory variables were monitored. Sedation and pain were assessed preoperatively and at various time points up to 24 hours after extubation using sedation scoring, an interactive visual analog scale, the UNESP-Botucatu multidimensional composite pain scale (MCPS) and mechanical nociceptive thresholds (MNT; von Frey anesthesiometer). Rescue analgesia (morphine, 0.1 mg kg^-1) IM was administered if the MCPS ≥6. Data were analyzed using the chi-square test, Tukey test, Kruskal-Wallis test and Friedman test (p < 0.05).

RESULTS

HR was significantly lower in ROP-DEX compared with Control (p = 0.002). The pain scores, MNT, sedation scores and the postoperative rescue analgesia did not differ statistically among groups.

CONCLUSIONS AND CLINICAL RELEVANCE

As part of a multimodal pain therapy, IP ropivacaine-dexmedetomidine was associated with decreased HR intraoperatively; however, SAP remained within normal limits. Using the stated anesthetic protocol, neither IP ropivacaine nor ropivacaine-dexmedetomidine significantly improved analgesia compared with IP saline in cats undergoing ovariohysterectomy.

Intraperitoneal and incisional analgesia in small animals: simple, cost-effective techniques

The World Small Animal Veterinary Association Global Pain Council (WSAVA-GPC) has recently published its first "capsule review" by Monteiro et al. These are short articles that present a brief assessment of the scientific evidence and practical recommendations on important, and sometimes controversial, subjects in pain management. The capsules will be published regularly in the Journal of Small Animal Practice, the official journal of the WSAVA. This second article discusses the use of intraperitoneal and incisional analgesia in small animal practice, including their limitations and recommendations by the authors.

Pressure algometry for assessment of abdominal wall sensitivity in horses after ventral midline coeliotomy

OBJECTIVE

To assess the clinical course of abdominal wall sensitivity after ventral midline coeliotomy in horses by determining mechanical nociceptive thresholds (MNTs) during hospitalization, and to determine the inter-observer reliability of pressure algometry on the abdominal wall.

STUDY DESIGN

Observational, cohort study.

SAMPLE POPULATION

A total of 13 horses presenting with signs of abdominal pain/colic undergoing ventral midline coeliotomy and 10 healthy horses without an abdominal incision.

METHODS

Measurements were performed on days 1, 3, 5, 7 and 9 postoperatively using a pressure algometer. Measurement sites were marked left and right, abaxial to the abdominal incision. Cranial to the incision, two control points were marked. Measurements were made by one observer, blinded to the recorded MNT values. To determine inter-observer reliability, five horses (surgical group n = 2; nonsurgical group n = 3) were measured by two observers in a randomized order.

RESULTS

Mean MNT values on days 5 and 7 were 9.61 Ncm^-2 and 10.14 Ncm^-2 in the operated group (p = 0.009 ; p = 0.005) respectively versus 13.00 Ncm^-2 on day 1. Wound-associated points showed lower values than control points (p = 0.002). The nonsurgical group did not show a difference between control points and wound-associated points (p = 0.06). No significant differences were found between the surgical and the nonsurgical groups at the wound-associated points on any days measured. The inter-observer reliability was low (intraclass correlation coefficient of 0.26; Cronbach's alpha of 0.27).

CONCLUSION

Operated animals showed a reduction in MNT values on days 5 and 7 when compared with day 1 and lower values for the wound-associated points when compared with the control points. Inter-observer reliability was low. Pressure algometry could be a useful tool for assessing wound sensitivity after ventral midline coeliotomy in horses, which may improve pain management postoperatively.

Low-level laser therapy (LLLT) accelerates the sternomastoid muscle regeneration process after myonecrosis due to bupivacaine

BACKGROUND

Because of its long-lasting analgesic action, bupivacaine is an anesthetic used for peripheral nerve block and relief of postoperative pain. Muscle degeneration and neurotoxicity are its main limitations. There is strong evidence that low-level laser therapy (LLLT) assists in muscle and nerve repair. The authors evaluated the effects of a Gallium Arsenide laser (GaAs), on the regeneration of muscle fibers of the sternomastoid muscle and accessory nerve after injection of bupivacaine.

METHODS

In total, 30 Wistar adult rats were divided into 2 groups: control group (C: n=15) and laser group (L: n=15). The groups were subdivided by antimere, with 0.5% bupivacaine injected on the right and 0.9% sodium chloride on the left. LLLT (GaAs 904nm, 0,05W, 2.8J per point) was administered for 5 consecutive days, starting 24h after injection of the solutions. Seven days after the trial period, blood samples were collected for determination of creatine kinase (CK). The sternomastoid nerve was removed for morphological and morphometric analyses; the surface portion of the sternomastoid muscle was used for histopathological and ultrastructural analyses. Muscle CK and TNFα protein levels were measured.

RESULTS

The anesthetic promoted myonecrosis and increased muscle CK without neurotoxic effects. The LLLT reduced myonecrosis, characterized by a decrease in muscle CK levels, inflammation, necrosis, and atrophy, as well as the number of central nuclei in the muscle fibers and the percentage of collagen. TNFα values remained constant.

CONCLUSIONS

LLLT, at the dose used, reduced fibrosis and myonecrosis in the sternomastoid muscle triggered by bupivacaine, accelerating the muscle regeneration process.