Clinical evaluation of ketamine and lidocaine intravenous infusions to reduce isoflurane requirements in horses under general anaesthesia

ObjectiveTo compare isoflurane alone or in combination with systemic ketamine and lidocaine for general anaesthesia in horses.Study designProspective, randomized, blinded clinical trial.AnimalsForty horses (ASA I-III) undergoing elective surgery.MethodsHorses were assigned to receive isoflurane anaesthesia alone (ISO) or with ketamine and lidocaine (LKI). After receiving romifidine, diazepam, and ketamine, the isoflurane end-tidal concentration was set at 1.3% and subsequently adjusted by the anaesthetist (unaware of treatments) to maintain a light plane of surgical anaesthesia. Animals in the LKI group received lidocaine (1.5 mg kg⁻¹ over 10 minutes, followed by 40 μg kg⁻¹ minute⁻¹) and ketamine (60 μg kg⁻¹ minute⁻¹), both reduced to 65% of the initial dose after 50 minutes, and stopped 15 minutes before the end of anaesthesia. Standard clinical cardiovascular and respiratory parameters were monitored. Recovery quality was scored from one (very good) to five (very poor). Differences between ISO and LKI groups were analysed with a two-sample t-test for parametric data or a Fischer's exact test for proportions (p < 0.05 for significance). Results are mean ± SD.ResultsHeart rate was lower (p = 0.001) for LKI (29 ± 4) than for ISO (34 ± 6). End-tidal concentrations of isoflurane (ISO: 1.57% ± 0.22; LKI: 0.97% ± 0.33), the number of horses requiring thiopental (ISO: 10; LKI: 2) or dobutamine (ISO:8; LKI:3), and dobutamine infusion rates (ISO:0.26 ± 0.09; LKI:0.18 ± 0.06 μg kg⁻¹ minute⁻¹) were significantly lower in LKI compared to the ISO group (p < 0.001). No other significant differences were found, including recovery scores.Conclusions and clinical relevanceThese results support the use of lidocaine and ketamine to improve anaesthetic and cardiovascular stability during isoflurane anaesthesia lasting up to 2 hours in mechanically ventilated horses, with comparable quality of recovery.     

Postoperative analgesic effects of either a constant rate infusion of fentanyl,lidocaine, ketamine,dexmedetomidine, or the combination lidocaine‐ketamine‐dexmedetomidine after ovariohysterectomy in dogs

ObjectiveTo evaluate the postoperative analgesic effects of a constant rate infusion (CRI) of either fentanyl (FENT), lidocaine (LIDO), ketamine (KET), dexmedetomidine (DEX), or the combination lidocaine-ketamine-dexmedetomidine (LKD) in dogs.Study designRandomized, prospective, blinded, clinical study.AnimalsFifty-four dogs.MethodsAnesthesia was induced with propofol and maintained with isoflurane. Treatments were intravenous (IV) administration of a bolus at start of anesthesia, followed by an IV CRI until the end of anesthesia, then a CRI at a decreased dose for a further 4 hours: CONTROL/BUT (butorphanol 0.4 mg kg⁻¹, infusion rate of saline 0.9% 2 mLkg⁻¹ hour⁻¹); FENT (5 μg kg⁻¹, 10 μg kg⁻¹hour⁻¹, then 2.5 μg kg⁻¹ hour⁻¹); KET (1 mgkg⁻¹, 40 μg kg⁻¹ minute⁻¹, then 10 μg kg⁻¹minute⁻¹); LIDO (2 mg kg⁻¹, 100 μg kg⁻¹ minute⁻¹, then 25 μg kg⁻¹ minute⁻¹); DEX (1 μgkg⁻¹, 3 μg kg⁻¹ hour⁻¹, then 1 μg kg⁻¹ hour⁻¹); or a combination of LKD at the aforementioned doses. Postoperative analgesia was evaluated using the Glasgow composite pain scale, University of Melbourne pain scale, and numerical rating scale. Rescue analgesia was morphine and carprofen. Data were analyzed using Friedman or Kruskal–Wallis test with appropriate post-hoc testing (p < 0.05).ResultsAnimals requiring rescue analgesia included CONTROL/BUT (n = 8), KET (n = 3), DEX (n = 2), and LIDO (n = 2); significantly higher in CONTROL/BUT than other groups. No dogs in LKD and FENT groups received rescue analgesia. CONTROL/BUT pain scores were significantly higher at 1 hour than FENT, DEX and LKD, but not than KET or LIDO. Fentanyl and LKD sedation scores were higher than CONTROL/BUT at 1 hour.Conclusions and clinical relevanceLKD and FENT resulted in adequate postoperative analgesia. LIDO, CONTROL/BUT, KET and DEX may not be effective for treatment of postoperative pain in dogs undergoing ovariohysterectomy.     

Worm control practice against gastro-intestinal parasites in Norwegian sheep and goat flocks

Background

Anthelmintic treatment is the most common way of controlling nematode infections in ruminants. However, several countries have reported anthelmintic resistance (AR), representing a limitation for sustainable small ruminant production. The knowledge regarding worm control management represents a baseline to develop a guideline for preventing AR. The aim of the present study was therefore to improve our knowledge about the worm control practices in small ruminant flocks in Norway.

Methods

A questionnaire survey regarding worm control practices was performed in small ruminant flocks in Norway. Flocks were selected from the three main areas of small ruminant farming, i.e. the coastal, inland and northern areas. A total of 825 questionnaires, comprising 587 sheep flocks (return rate of 51.3%) and 238 goat flocks (52.6%) were included.

Results

The results indicated that visual appraisal of individual weight was the most common means of estimating the anthelmintic dose used in sheep (78.6%) and goat (85.1%) flocks. The mean yearly drenching rate in lambs and ewes were 2.5 ± 1.7 and 1.9 ± 1.1, respectively, whereas it was 1.0 (once a year) in goats. However, these figures were higher in sheep in the coastal area with a rate of 3.4 and 2.2 in lambs and ewes, respectively. Benzimidazoles were the predominant anthelmintic class used in sheep flocks (64.9% in 2007), whereas benzimidazoles and macrocyclic lactones were both equally used in dairy goat flocks. In the period of 2005-2007, 46.3% of the sheep flocks never changed the anthelmintic class. The dose and move strategy was practiced in 33.2% of the sheep flocks.

Conclusions

The present study showed that inaccurate weight calculation gives a risk of under-dosing in over 90% of the sheep and goat flocks in Norway. Taken together with a high treatment frequency in lambs, a lack of anthelmintic class rotation and the common use of a dose-and-move strategy, a real danger for development of anthelmintic resistance (AR) seems to exist in Norwegian sheep and goat flocks. This risk seems particularly high in coastal areas where high treatment frequencies in lambs were recorded.     

Risk factors for porcine reproductive and respiratory syndrome outbreaks in Vietnamese small stock farms

AIM: To examine risk factors that could have played a role in the 2010 porcine reproductive and respiratory syndrome (PRRS) outbreak in Yenhung district, Quangninh province, North-Vietnam, with the purpose of establishing why existing control measures implemented after previous outbreaks had failed to prevent further outbreaks.

METHODS: A case-control study was carried out in Yenhung district. Data were obtained by an interview-based questionnaire survey. The sampling unit was households, which equated to small-scale pig farms. A total of 150 case and 150 control households were selected at communes affected by the 2010 PRRS epidemic during April to June. Risk factors were analysed using binary logistic regression and unconditional multiple logistic regression.

RESULTS: Households infected with PRRS were significantly associated with multiple variables belonging to three main groups: (1) location of the farms: i.e. farms positioned <1,000?m from a pig abattoir or within 500?m of local markets or 100?m of main roads; (2) farm management: i.e. where there was non-application of weekly farm disinfection, feeding uncooked swill, new introduction of purchased pigs without isolation, or usage of water from irrigation systems for raising pigs; (3) people and animal contact: i.e. where households kept animals with either no confinement or partial confinement, had visits by family members to other affected farms or had frequent visits by neighbours. The use of water from irrigation systems was found to be the risk factor most strongly associated with infected households in the 2010 outbreak (OR=22; 95% CI=12–42).

CONCLUSIONS: The results show that the epidemiology of PRRS in Quangninh province was linked to sociological and cultural practices, and that effective PRRS control needs an integrated approach coupled with behavioural changes in the pig raising practices of the general public. Failure to recognise this could explain why further outbreaks have occurred.     

Prediction of atrazine sorption coefficients in soils using mid-infrared spectroscopy and partial least-squares analysis

This study explored the potential of mid-infrared spectroscopy (MIR) with partial least-squares (PLS) analysis to predict sorption coefficients (Kd) of pesticides in soil. The MIR technique has the advantage of being sensitive to both the content and the chemistry of soil organic matter and mineralogy, the important factors in the sorption of nonionic pesticides. MIR spectra and batch Kd values of atrazine were determined on a set of 31 soil samples as reference data for PLS calibration. The samples, with high variability in soil organic carbon content (SOC), were chosen from 10 southern Australian soil profiles (A1, A2, B, and C in one case). PLS calibrations, developed for the prediction of Kd from the MIR spectra and reference Kd data, were compared with predictions from Koc-based indirect estimation using SOC content. The reference Kd data for the 31 samples ranged from 0.31 to 5.48 L/kg, whereas Koc ranged from 30 to 680 L/kg. Both coefficients generally increased with total SOC content but showed a relatively poor coefficient of determination (R2 = 0.53; P > 0.0001) and a high standard error of prediction (SEP =1.22) for the prediction of Kd from Koc. This poor prediction suggested that total SOC content alone could explain only half of the variation in Kd. In contrast, the regression plot of PLS predicted versus measured Kd resulted in an improved correlation, with R2 = 0.72 ( P > 0.0001) and standard error of cross-validation (SECV) = 0.63 for three PLS factors. With the advantages of MIR-PLS in mind, (i) more accurate prediction of Kd, (ii) an ability to reflect the nature and content of SOC as well as mineralogy, and (iii) high repeatability and throughput, it is proposed that MIR-PLS has the potential for an improved and rapid assessment of pesticide sorption in soils.     

Current attitudes to,and use of,peri-operative analgesia in dogs and cats by veterinarians in New Zealand

AIM: To investigate the attitudes of veterinary practitioners in New Zealand to pain and analgesia, and their use of analgesic drugs, in dogs and cats.

METHODS: A questionnaire posted to 1,200 practising veterinarians was used to gather information about the use of analgesia in dogs and cats, assessment of pain, attitudes to pain relief, analgesic drugs and procedures used, factors affecting choice of analgesic agent, and veterinary demographics, continuing education and staffing.

RESULTS: Three hundred and twenty questionnaires with useable data were returned, a response rate of 28%. Male and female veterinarians were evenly represented. The analgesic agents most commonly used were morphine (opioids) and carprofen (a non-steroidal anti-inflammatory drug; NSAID). Use of peri-operative pain relief ranged from 50% for castration of cats to 91% for fracture repair in dogs. For most procedures, female veterinarians scored pain at a significantly higher level than their male colleagues. Fifty-eight percent of respondents considered their knowledge in the area of assessment and treatment of pain was adequate.

CONCLUSIONS: This survey was considered representative of veterinarians working in companion animal practice in New Zealand. Results indicated a relatively high use of peri-operative analgesia, including both pre-emptive and multi-modal analge- sia, in cats and dogs, although there was still some disparity between the perception of how painful a procedure was and the consequent use of pain relief.

CLINICAL RELEVANCE: The establishment of current attitudes and practices indicates to practising veterinarians how their own use of analgesics compares with that of their colleagues. It also provides information to educators on potential areas of focus, given that 42% of respondents felt their knowledge in the area of assessment and treatment of pain was inadequate.