A prospective randomized, double-blinded clinical study evaluating the efficacy and safety of bupivacaine versus morphine-bupivacaine in caudal epidurals in cats with urethral obstruction

Anaesthetic mortality in cats: A worldwide analysis and risk assessment

BACKGROUND

Patient safety is essential in small animal anaesthesia. This study aimed to assess anaesthesia-related deaths in cats worldwide, identify risk and protective factors and provide insights for clinical practice.

METHODS

A prospective multicentre cohort study of 14,962 cats from 198 veterinary centres across different countries was conducted. Data on anaesthesia-related deaths, from premedication up to 48 hours postextubation, were collected. Logistic regression was used to analyse patient demographics, American Society of Anesthesiologists (ASA) classification, procedure type and anaesthetic drugs.

RESULTS

The anaesthesia-related mortality was 0.63%, with 74.5% of deaths occurring postoperatively. Cats with cachexia, a higher ASA status or who underwent abdominal, orthopaedic/neurosurgical or thoracic procedures exhibited elevated mortality. Mechanical ventilation use was associated with increased mortality. Mortality odds were reduced by the use of alpha2-agonist sedatives, pure opioids in premedication and locoregional techniques.

LIMITATIONS

Limitations include non-randomised sampling, potential biases, unquantified response rates, subjective death cause classification and limited variable analysis.

CONCLUSIONS

Anaesthetic mortality in cats is significant, predominantly postoperative. Risk factors include cachexia, higher ASA status, specific procedures and mechanical ventilation. Protective factors include alpha2-agonist sedatives, pure opioids and locoregional techniques. These findings can help improve anaesthesia safety and outcomes. However, further research is required to improve protocols, enhance data quality and minimise risks.

Sacrococcygeal epidural administration of 0.5% bupivacaine in seven cats undergoing pelvic or hind limb orthopaedic procedures

BACKGROUND

Epidural administration of local anaesthetic agents provides good intraoperative antinociception for orthopaedic procedures of the pelvis and the pelvic limb. However, in cats the spinal cord extends approximately to the level of the first sacrococcygeal vertebra, and therefore the sacrococcygeal epidural could be a safer alternative to the lumbosacral epidural in cats. This case series describes perioperative analgesia and the haemodynamic status of seven client-owned cats that received sacrococcygeal epidural injection of 0.5% bupivacaine and underwent orthopaedic hind leg or pelvic surgeries under general anaesthesia.

CASE PRESENTATION

Each cat received either 0.2 or 0.3 mL/kg of 0.5% bupivacaine with or without 0.2 mg/kg of morphine in the sacrococcygeal epidural space. Intraoperative antinociceptive response to surgical stimulus and haemodynamic changes were monitored and reported.

CONCLUSION

In these seven anaesthetised cats, 0.2 or 0.3 mL/kg of 0.5% bupivacaine, administered alone or in combination with morphine into the sacrococcygeal epidural space, enhanced antinociception so that intraoperative rescue analgesia was unnecessary in all but one cat. It also reduced the anticipated requirement for postoperative opioid use. However, a high incidence of hypotension was observed in the cats in this report, and hence intraoperative blood pressure monitoring should be considered mandatory in anaesthetised cats following epidural injection of local anaesthetic agents, regardless of injection site.

Retrospective evaluation of the effect of inhalant anesthesia on complications and recurrence rates in feline urethral obstruction

OBJECTIVES

The aim of this study was to evaluate the use of inhalant anesthesia vs sedation for urinary catheter placement in male cats with urethral obstruction. The primary outcome measures were the incidence of complications related to catheterization, the incidence of recurrent urethral obstruction (rUO; both during hospitalization and within 1 year) and survival. The secondary aim of this study was to evaluate the association between baseline serum biochemical concentrations and antispasmodic medications with complications and short-term rUO.

METHODS

We carried out a retrospective review of records from a university teaching hospital from 2009 to 2020. Cats were included if diagnosed with a urinary obstruction, based on the presence of a large, painful and non-expressible bladder, a urinary catheter was placed and hospitalization occurred for a minimum of 24 h. Collected baseline data included age, breed, weight, serum biochemical concentrations and if cats underwent sedation or inhalant anesthesia for urethral catheterization. For the comparison of inhalant anesthesia or sedation, univariate logistic regression was used.

RESULTS

There was no statistically significant difference in complications or the recurrence of obstruction in cats with urethral obstruction that underwent inhalant anesthesia compared with sedation. All serum biochemical concentrations were significantly associated with survival. Decreased serum ionized calcium was found to be statistically significantly associated with higher complication rates (P = 0.0086), as well as short-term recurrence of obstruction (P = 0.004). Increased serum potassium concentrations were found to be statistically significantly associated with the risk of short-term recurrent urethral obstruction (P = 0.0345). No significant difference was found between the use of antispasmodic medications with short-term recurrence.

CONCLUSIONS AND RELEVANCE

No significant difference was found between complications or recurrence rates when comparing the use of inhalant anesthesia to sedation protocols. Baseline serum biochemical data were significantly associated with complications, survival and short-term recurrence rates.

2022 ISFM Consensus Guidelines on the Management of Acute Pain in Cats

PRACTICAL RELEVANCE

Increases in cat ownership worldwide mean more cats are requiring veterinary care. Illness, trauma and surgery can result in acute pain, and effective management of pain is required for optimal feline welfare (ie, physical health and mental wellbeing). Validated pain assessment tools are available and pain management plans for the individual patient should incorporate pharmacological and non-pharmacological therapy. Preventive and multimodal analgesia, including local anaesthesia, are important principles of pain management, and the choice of analgesic drugs should take into account the type, severity and duration of pain, presence of comorbidities and avoidance of adverse effects. Nursing care, environmental modifications and cat friendly handling are likewise pivotal to the pain management plan, as is a team approach, involving the cat carer.

CLINICAL CHALLENGES

Pain has traditionally been under-recognised in cats. Pain assessment tools are not widely implemented, and signs of pain in this species may be subtle. The unique challenges of feline metabolism and comorbidities may lead to undertreatment of pain and the development of peripheral and central sensitisation. Lack of availability or experience with various analgesic drugs may compromise effective pain management.

EVIDENCE BASE

These Guidelines have been created by a panel of experts and the International Society of Feline Medicine (ISFM) based on the available literature and the authors' experience. They are aimed at general practitioners to assist in the assessment, prevention and management of acute pain in feline patients, and to provide a practical guide to selection and dosing of effective analgesic agents.

Multicenter evaluation of decompressive cystocentesis in the treatment of cats with urethral obstruction

OBJECTIVE

To investigate whether decompressive cystocentesis (DC) safely facilitates urethral catheterization (UC) in cats with urethral obstruction (UO).

ANIMALS

88 male cats with UO.

PROCEDURES

Cats were randomly assigned to receive DC prior to UC (ie, DC group cats; n = 44) or UC only (ie, UC group cats; 44). Abdominal effusion was monitored by serial ultrasonographic examination of the urinary bladder before DC and UC or before UC (DC and UC group cats, respectively), immediately after UC, and 4 hours after UC. Total abdominal effusion score at each time point ranged from 0 (no effusion) to 16 (extensive effusion). Ease of UC (score, 0 [easy passage] to 4 [unable to pass]), time to place urinary catheter, and adverse events were recorded.

RESULTS

No significant difference was found in median time to place the urinary catheter in UC group cats (132 seconds), compared with DC group cats (120 seconds). Median score for ease of UC was not significantly different between UC group cats (score, 1; range, 0 to 3) and DC group cats (score, 1; range, 0 to 4). Median change in total abdominal effusion score from before UC and DC to immediately after UC was 0 and nonsignificant in UC group cats (range, -5 to 12) and DC group cats (range, -4 to 8). Median change in effusion score from immediately after UC to 4 hours after UC was not significantly different between UC group cats (score, -1; range, -9 to 5) and DC group cats (score, -1; range, -7 to 5).

CONCLUSIONS AND CLINICAL RELEVANCE

DC did not improve time to place the urinary catheter or ease of UC in cats with UO.