Postoperative pain and perioperative analgesic administration in dogs: practices, attitudes and beliefs of Queensland veterinarians

Objective The aim of this study was to describe the practices, attitudes and beliefs of Queensland veterinarians in relation to postoperative pain and perioperative analgesia in dogs. Methods One veterinarian from each of the 50 randomly selected Queensland veterinary practices was enrolled after selection by convenience sampling. Results The study response rate was 94.3%. Demeanour, vocalisation and heart rate were the most common postoperative pain assessment tools used, even though the most sensitive tools were considered to be demeanour, heart rate and respiratory rate. Only 20% of respondents used formalised pain scoring systems. Preoperative analgesic administration was always used by 72% of respondents. There was marked variability in the frequency with which analgesia was administered perioperatively for ovariohysterectomy. Only 24% of veterinarians discharged animals with ongoing analgesia even though 38% agreed that pain is still present 7 days postoperatively. Multimodal analgesia was used by 82% of respondents. Epidural and local anaesthetic analgesic techniques were not being utilised by any respondents. Conclusions These results indicate that management of postoperative pain in dogs in Queensland is frequently suboptimal and, at times, is not consistent with the veterinarian's attitudes and beliefs. Continuing education into analgesic use and pain evaluation may be effective in addressing this.     

Effect of intravenous dose escalation with alfaxalone and propofol on occurrence of apnoea in the dog

Spontaneous ventilation after induction of anaesthesia with intravenous alfaxalone or propofol was evaluated in a dose escalation study using 6 dogs. Each dog was dosed at 1×, 2×, 5×, 10× and 20× multiples of the labelled doses (2mg/kg for alfaxalone; 6.5mg/kg for propofol), until apnoea was observed. For each administration, the entire calculated dose was delivered over 1 min. All 6 dogs ventilated spontaneously after labelled (1×) doses of each drug but became apnoeic at 5× dose of propofol versus 20× dose of alfaxalone. For propofol at 2× and 5× doses, 4 and 0 dogs ventilated spontaneously respectively. For alfaxalone at 2×, 5× and 10× doses all 6, 4 and 1 dog ventilated spontaneously, respectively. The median dose which induced apnoea was higher for alfaxalone (5×) than for propofol (2×) (p=0.05). We concluded that induction of anaesthesia with propofol is more likely to induce apnoea than with alfaxalone.     

Long term use of hydraulic artificial urethral sphincters in nine dogs from New Zealand with urethral sphincter mechanism incompetence

AIMS: To report on the long-term outcomes of hydraulic artificial urethral sphincter (HAUS) placement for the correction of urethral sphincter mechanism incompetence (USMI) in New Zealand dogs.

METHODS: Retrospective data were obtained from cases of dogs which had a HAUS placed after failed medical and/or surgical management of USMI between August 2012 and November 2016. Owner assessment of urinary incontinence was evaluated by an online survey in May 2017 using a visual analogue scale (0 being normal, 100 being severely affected) for the frequency, volume and severity of any straining to urinate, immediately prior to the placement of the HAUS and at the time of the survey. The number of days between surgery and the completion of survey were recorded.

RESULTS: Seven females and two male dogs, which were all desexed except for one female, were eligible for inclusion in the study. The period of follow-up following HAUS placement ranged from 206–1,685 days. Following HAUS placement, frequency and volume of urinary incontinence decreased for six dogs and were practically unchanged for three dogs. The median frequency score decreased from 70 to 13 and the volume score decreased from 73 to 12. There was no consistent change in the perceived degree of straining to urinate. Complications occurred in three dogs; one required repositioning of a dislodged injection port, one required management for haematuria and a hypoplastic bladder, and one required surgical removal of fibrous tissue around the HAUS cuff.

CONCLUSIONS AND CLINICAL RELEVENCE: HAUS placement was an effective method for the treatment of persistent USMI in most dogs and provided good clinical results based on owner assessment. The technique was associated with few complications and allowed successful long-term control of urinary incontinence without the need for medical management.     

Assessment of three variations of the 1,9-dimethylmethylene blue assay for measurement of sulfated glycosaminoglycan concentrations in equine synovial fluid

OBJECTIVE: To determine whether 3 variations of the 1,9-dimethylmethylene blue (DMMB) assay yield comparable results when measuring sulfated glycosaminoglycan (sGAG) concentrations in equine synovial fluid (SF). SAMPLE POPULATION: 25 samples of SF collected from affected joints of 13 horses and 13 samples of SF collected from nonaffected (control) joints of 4 horses. PROCEDURE: Sulfated glycosaminoglycan concentrations were measured by the direct spectrophotometric (ie, Farndale), microplate, and indirect DMMB assays in samples of SF collected from normal and affected joints and in samples digested with nucleases, papain, and hyaluronidase. RESULTS: All 3 assays reacted similarly to standard solutions of sGAGs and digestion of SF samples with nucleases, papain, and hyaluronidase. Nucleic acids were not important interfering substances, and papain and hyaluronidase could not be used interchangeably to digest SE All 3 assays proved to have satisfactory precision (SD < 10%), but each DMMB assay resulted in significantly different measures of sGAG in equine SF. CONCLUSIONS AND CLINICAL RELEVANCE: Samples of SF should be digested with papain or hyaluronidase prior to measurement via DMMB assay. Researchers currently are unable to compare clinical information when variations of the DMMB assay are used, because each DMMB assay yields substantially different sGAG concentrations in SF. Of the 3 assays examined here, we recommend use of the direct spectrophotometric DMMB assay.     

LOW-FIELD MRI AND ARTHROSCOPY OF MENISCAL LESIONS IN TEN DOGS WITH EXPERIMENTALLY INDUCED CRANIAL CRUCIATE LIGAMENT INSUFFICIENCY

Little is known about the magnetic resonance imaging (MRI) appearance of canine meniscal lesions. The aim of this study is to describe the MR appearance of meniscal lesions in dogs with experimentally induced cranial cruciate ligament (CCL) deficiency. The pilot study revealed dogs weighing approximately 10 kg to be too small for meniscal evaluation on low-field MRI. In the main study, dogs weighing approximately 35 kg were used. The left CCL was transected and low-field MRI was performed regularly until 13 months post-surgery. Normal menisci were defined as grade 0. Intrameniscal lesions not reaching any surface corresponded to grade 1 if focal and to grade 2 if linear or diffuse. Grade 3 lesions consisted in linear tears penetrating a meniscal surface. Grade 4 lesions included complex signal changes or meniscal distortion. Between 2 and 13 months post-surgery, all dogs developed grade 4 lesions in the medial meniscus. Most of them corresponded to longitudinal or bucket handle tears on arthroscopy and necropsy. Two dogs showed grade 3 lesions reaching the tibial surface of the lateral meniscus on MRI but not in arthroscopy. Such tears are difficult to evaluate arthroscopically; MRI provides more accurate information about the tibial meniscal surface. Grades 1 and 2 lesions could not be differentiated from presumably normal menisci with our imaging technique. An MRI grading system better adapted to canine lesions has yet to be developed. MRI is a helpful tool for the diagnosis of complete tears in the canine meniscus, especially in larger dogs.     

Evaluation of an Immunochromatographic Test to the Diagnosis of Canine Brucellosis Caused by Brucella canis

This study evaluated the performance of an immunochromatographic test (ICT) for the diagnosis of canine brucellosis caused by Brucella canis, comparing its results with that of the rapid slide agglutination test with and without the use of 2‐mercaptoethanol and the agar gel immunodiffusion test (AGID). The microbiological culture, PCR and clinical examination were used as reference. According to the results obtained in clinical examination, blood culture, culture of semen and vaginal swab and PCR in blood, semen and vaginal swab, a total of 102 dogs were divided into three groups: B. canis‐infected dogs (Group 1), B. canis‐non‐infected dogs (Group 2) and dogs with suspected brucellosis (Group 3). The diagnostic sensitivity of RSAT, 2ME‐RSAT, AGID and ICT in Group 1 was, respectively, 75%, 37.5%, 27.8% and 89.58%. The diagnostic specificity of RSAT, 2ME‐RSAT, AGID and ICT in Group 2 was, respectively, 91%, 100%, 100%, and 100%. In dogs with suspected brucellosis, 9.67% were RSAT positive, none was positive by 2ME‐RSAT, 3.22% were AGID positive and 6.45% were ICT positive. The main drawback concerning canine brucellosis diagnosis is the lack of a highly sensitive serological assay to be used as a screening test to the rapid identification of infected animals. The ICT showed a high diagnostic specificity and a diagnostic sensitivity value greater than that observed in the RSAT, 2ME‐RSAT and AGID. However, 10.41% of infected dogs had negative results by ICT. These dogs were positive by microbiological culture and/or PCR, indicating active infection and consequently a higher potential of spreading Brucella. Although rapid and simple to perform, the ICT lacked sensitivity to be used as a screening test.     

Plasma pharmacokinetics of alfaxalone after a single intraperitoneal or intravenous injection of Alfaxan® in rats

Alfaxalone (3α‐hydroxy‐5α‐pregnane‐11, 20‐dione) is a neuroactive steroid with anaesthetic properties and a wide margin of safety. The pharmacokinetic properties of alfaxalone administered intravenously and intraperitoneally in rats (n = 28) were investigated. Mean t_1/2elim for 2 and 5 mg/kg i.v. was 16.2 and 17.6 min, respectively, but could not be estimated for IP dosing, due to sustained plasma levels for up to 60 min after injection. Cl_p for i.v. injection was calculated at 57.8 ± 23.6 and 54.3 ± 6.8 mL/min/kg, which were 24.5% and 23% of cardiac output, respectively. The observed C_max was 3.0 mg/L for IP administration, and 2.2 ± 0.9 and 5.2 ± 1.3 mg/L for 2 and 5 mg/kg i.v. administration, respectively. AUC_0–60 was 96.2 min·mg/L for IP dosing. The relative bioavailability for IP dosing was 26% and 28% compared to i.v. dosing. Differences in t_1/2elim and Cl_p from previous pharmacokinetic studies in rats are likely due to variations in alfaxalone formulation rather than sex differences. Alfaxan^® given IP caused sustained levels of alfaxalone, no apnoea and longer sleep times than i.v. dosing, although immobilization was not induced in 30% of rats given Alfaxan^® IP. A pharmacodynamic study of the effects of combining IP injection of Alfaxan^® with other premedication agents is worthwhile, to determine whether improved anaesthesia induction could ultimately provide an alternative anaesthetic regimen for rats.