Feline procedural sedation and analgesia: When, why and how

Use of Caudal Quadratus Lumborum Block with Ropivacaine as Part of an Opioid-Free Analgesic Protocol in Dogs Undergoing Orchiectomy: A Randomized Trial

In veterinary medicine, the use of loco-regional anesthesia techniques is increasing. The Quadratus Lumborum block (QL) is an interfascial loco-regional technique that involves the release of local anesthetic (LA) between the Quadratus Lumborum and the Small Psoas (Pm) muscle. The study aims to evaluate the effect of the QL block on reducing the total amount of opioids in dogs undergoing pre-scrotal orchiectomy. A group of 36 dogs was enrolled in a randomized blinded study. The animals were divided into two groups: 18 in the experimental group (QL) and 18 in the control group (C). The QL group received 0.4 mL kg-1 of ropivacaine 0.5% for each hemiabdomen (total amount of 3 mg kg-1 of ropivacaine, 1.5 mg kg-1 per side). The C group was brought into the operating room (OR) after receiving the same clipping as the QL group. In the intraoperative period, opioid consumption in the QL group was significantly lower than in the C group. No differences were found in the post-operative phase. No side effects were reported when performing the QL technique. The QL block performed at the level of L6 appears to be a valid approach to reducing opioid use in dogs undergoing orchidectomy with a pre-scrotal surgical approach.

A Comparison of the Intrarectal and Intramuscular Effects of a Dexmedetomidine, Ketamine and Midazolam Mixture on Tear Production in Cats: A Randomized Controlled Trial

Cats are often easily stressed and uncooperative. The use of sedative agents in the feline species is widely used to perform even minor clinical and diagnostic procedures. The aim of this study is to assess the impact on tear film production of the intrarectal route (IR) administration of a mixture of dexmedetomidine, ketamine and midazolam in comparison with the intramuscular (IM) one. A group of twenty cats were involved in a randomized and blinded clinical trial. A clinical and ophthalmological examination was conducted on the cats. The IR group received dexmedetomidine 0.003 mg kg-1, ketamine 4 mg kg-1 and midazolam 0.4 mg kg-1; the IM group received dexmedetomidine 0.003 mg kg-1, ketamine 2 mg kg-1 and midazolam 0.2 mg kg-1. A Shirmer tear test I (STT- I) was conducted 1 h before sedation and 2', 10', 20', 30', 40', and 80' post drug administration. The reaction to STT-I administration was also evaluated. The IM group has a lower mean tear production than the IR group for all time points evaluated. Cats in the IM group showed less reaction to STT-I administration. This study may suggest that the effect of sedative agents administered by the IR route has a lower incidence on tear production than the IM one. The use of eye lubricant is recommended in any case.

Effects of different rates of propofol with or without S-ketamine on ventricular function in healthy cats - a randomized study

Propofol is used for anesthetic induction in cats and procedural sedation in countries where alfaxalone is not available. Studies have reported propofol-related effects in echocardiography variables in dogs and humans. However, there is a lack of echocardiography studies investigating propofol-related effects on cats. This study aimed to use echocardiography to investigate echocardiographic changes in three protocols using propofol: propofol-slow (2 mg/kg/min, PS); propofol-fast (8 mg/kg/min, PF); propofol-ketamine (S-ketamine 2 mg/kg bolus followed by propofol 2 mg/kg/min; PK) in healthy premedicated (gabapentin-buprenorphine-acepromazine; 200 mg/cat, 0.4, and 0.1 mg/kg, respectively), non-intubated cats. Echocardiographic measurements were obtained at three time points: baseline (before the administration of propofol), end of propofol titration (end-point, T0), and 15 min after T0 (T15). Propofol at a lower rate continued from T0 to T15. Echocardiographic and physiological variables included fractional shortening (FS%), ejection fraction (EF%), HR, BP, and others. Propofol requirements at T0 for PF, PS, and PK groups were 5.0 ± 0.9, 3.8 ± 0.7, and 2.4 ± 0.5 mg/kg, respectively. EF% neither change over time nor between groups. PF and PK showed a reduction in FS% at T0 (47 ± 6 to 34 ± 6 and 42 ± 6 to 36 ± 5, respectively). BP reduced significantly in PF and PS groups (136 ± 26 to 105 ± 13 and 137 ± 22 to 115 ± 15 mmHg, respectively). It is unclear whether changes in echocardiography variables were of clinical relevance related to treatment groups or a result of within-group individual responses.

Intranasal dexmedetomidine with morphine or tramadol: A comparative study of effects on alfaxalone requirements for anesthesia in cats

Background and Aim

Intranasal (IN) sedatives provide a non-invasive route for premedication drug administration. This study compared the cardiorespiratory and sparing effects of IN dexmedetomidine combined with morphine (DM) or tramadol (DT) on alfaxalone requirements for anesthesia induction in cats.

Materials and Methods

Twenty-four cats were randomly assigned to three groups: Dexmedetomidine combined morphine (IN dexmedetomidine 20 μg/kg plus 0.2 mg/kg morphine), DT (IN dexmedetomidine 20 μg/kg plus 1 mg/kg tramadol), or control (no premedication). The intravenous dose of 1% alfaxalone for endotracheal intubation was recorded with sedation scores, cardiorespiratory parameters (heart rate and respiration rate), and side effects.

Results

Both DM and DT were associated with significantly higher sedation scores than baseline, and sedation scores were found to be highest 20 min after premedication. Sedation scores were comparable between DM and DT groups. Side effects, including hypersalivation, vomiting, and pupillary dilation, were observed in the DM and DT groups. The dosage of alfaxalone required in the DM group (1.5 ± 0.3 mg/kg) was comparable to that of the DT group (2.0 ± 0.6 mg/kg, p = 0.0861), and both groups required significantly less alfaxalone than the control group (3.0 ± 0.6 mg/kg; p < 0.01). Heart and respiratory rates were comparable between the DM and DT groups. Duration of anesthesia in the control group (11 ± 4 min) was significantly shorter than in the DM (29 ± 5 min, p = 0.0016) and DT (38 ± 14 min, p < 0.001) groups.

Conclusion

Intranasal administration of DM or DT produces good sedation and offers an alternative, non-invasive route for cats undergoing general anesthesia.

Effect of Dexmedetomidine Low Doses with or without Midazolam in Cats: Clinical, Hemodynamic, Blood Gas Analysis, and Echocardiographic Effects

Objectives. The aim of the study is to compare the sedative, cardiorespiratory, echocardiographic, and blood gas effects of dexmedetomidine and methadone associated or not with midazolam for restraint chemistry in cats. Methods. Eighteen healthy young cats (4.06 ± 0.48 kg) were randomly sedated with two protocols, through the intramuscular route: dexmedetomidine (5 µg.kg−1), methadone (0.3 mg. kg−1) and midazolam (0.3 mg. kg−1) (DMTM, n = 9), or dexmedetomidine (7.5 µg.kg−1) and methadone (0.3 mg. kg−1) (DMT, n = 9). The cardiorespiratory parameters were measured at baseline, 5 and 10 minutes after pharmacological latency. The sedation, analgesia, and muscle relaxation scores were assessed before and 5 minutes after pharmacological latency, while arterial blood gas analysis and echocardiography were assessed before and after 10 or 15 minutes, respectively. Results. There was no difference between the protocols regarding the cardiorespiratory, blood gas, and echocardiographic parameters used. The scores for sedation, analgesia, and muscle relaxation also did not differ between the protocols, with the degree of sedation, analgesia, and myorelaxation considered satisfactory in both groups. A significant decrease in heart rate (HR) was observed after administration of the sedative protocols, reaching a maximum reduction at T10 (46% and 53% reduction in the DMT and DMTM groups, respectively). The reduction in HR had an impact on echocardiographic parameters such as CO, which decreased 53% and 56% in the DMT and DMTM groups, respectively. There was a significant reduction in PaO2, SaO2, ejection fraction, and fractional shortening in both protocols. SpO2 decreased significantly after 5 minutes of sedation in the DMT group, but with a minimum mean SpO2 of 92% in T5. The respiratory rate decreased significantly at 5 and 10 minutes in the DMTM group, while PaCO2 increased in both groups, indicating respiratory depression caused by the drugs. Conclusions and Relevance. The study pointed out that both sedative protocols can be recommended for clinical sedation of young and healthy cats in the doses used. However, both protocols resulted in cardiorespiratory depression in cats and also the particularities of the animals should be evaluated regarding reducing cardiac output by more than 50%.

2022 ISFM/AAFP Cat Friendly Veterinary Environment Guidelines

PRACTICAL RELEVANCE

The '2022 ISFM/AAFP Cat Friendly Veterinary Environment Guidelines' (hereafter the 'Cat Friendly Veterinary Environment Guidelines') describe how the veterinary clinic environment can be manipulated to minimise feline patient distress. Many components of a veterinary clinic visit or stay may result in negative experiences for cats. However, much can be done to improve a cat's experience by making the veterinary clinic more cat friendly. Exposure to other cats and other species can be reduced, and adjustments made with consideration of the feline senses and species-specific behaviour. Caregivers can prepare cats for a clinic visit with appropriate advice. Waiting rooms, examination rooms, hospital wards and other clinic areas can be designed and altered to reduce stress and hence encourage positive emotions. Changes need not be structural or expensive in order to be effective and make a difference to the cats and, in turn, to cat caregivers and the veterinary team. Moreover, by improving the all-round experience at the veterinary clinic, there are positive effects on preventive healthcare, identification of and recovery from illness, and compliance with treatment.

CLINICAL CHALLENGES

Good feline healthcare necessitates visiting the veterinary clinic, which, simply by being outside of a cat's territory and familiar surroundings, may lead to negative experiences. Such experiences can trigger negative (protective) emotions and associated physiological stress, which can result in misleading clinical findings, patient distress, prolonged recovery from illness, further difficulties with handling at subsequent visits and potential veterinary personnel injury. There may be a mistaken belief that veterinary clinics must undergo significant renovation or building work to become cat friendly, and that, if species cannot be separated, then clinics cannot improve their care of cats. These Guidelines aim to dispel any such misconceptions and provide detailed practical advice.

EVIDENCE BASE

These Guidelines have been created by a Task Force of experts convened by the International Society of Feline Medicine and American Association of Feline Practitioners, based on an extensive literature review and, where evidence is lacking, the authors' experience. Endorsements: These Guidelines have been endorsed by a number of groups and organisations, as detailed on page 1161 and at icatcare.org/cat-friendly-guidelines and catvets.com/environment.

2022 AAFP/ISFM Cat Friendly Veterinary Interaction Guidelines: Approach and Handling Techniques

PRACTICAL RELEVANCE

The '2022 AAFP/ISFM Cat Friendly Veterinary Interaction Guidelines: Approach and Handling Techniques' (hereafter the 'Cat Friendly Veterinary Interaction Guidelines') support veterinary professionals with feline interactions and handling to reduce the impact of fear and other protective (negative) emotions, in so doing enhancing feline welfare and In implementing these Guidelines, team satisfaction and cat caregiver confidence in the veterinary team will increase as the result of efficient examinations, better experience, more reliable diagnostic testing and improved feline wellbeing. Veterinary professionals will learn the importance of understanding and appropriately responding to the current emotional state of the cat and tailoring each visit to the individual.

CLINICAL CHALLENGES

Cats have evolved with emotions and behaviors that are necessary for their survival as both a predator and prey species. A clinical setting and the required examinations and procedures to meet their physical health needs can result in behavioral responses to protective emotions. Cat friendly interactions require understanding, interpreting and appropriately responding to cats' emotional states and giving them a perceived sense of control while performing the required assessment.

EVIDENCE BASE

These Guidelines have been created by a Task Force of experts convened by the American Association of Feline Practitioners and the International Society of Feline Medicine, based on an extensive literature review and, where evidence is lacking, the authors' experience.

ENDORSEMENTS

These Guidelines have been endorsed by a number of groups and organizations, as detailed on page 1127 and at catvets.com/interactions and icatcare.org/cat-friendly-guidelines.

Comparison of Certain Intrarectal versus Intramuscular Pharmacodynamic Effects of Ketamine, Dexmedetomidine and Midazolam in Cats

The aim of this clinical trial was to evaluate the impacts of administration via the intrarectal route (IR) in cats on their heart and respiratory rates, blood pressure, body temperature, and sedation quality compared to the intramuscular route (IM). The intramuscular group (IMG) received 0.003 mg kg−1 dexmedetomidine, 2 mg kg−1 ketamine, and 0.2 mg kg−1 midazolam while the intrarectal group (IRG) protocol was 0.003 mg kg−1 dexmedetomidine, 4 mg kg−1 ketamine, and 0.4 mg kg−1 midazolam. Cardiorespiratory values, temperature, and sedation score were measured 2 min after administration and then every 5 min up to the 40th minute. Cats belonging to IRG reacted less strongly to the drug, as opposed to those receiving intramuscular administration (2/10 in IRG vs. 8/10 in IMG). Average time between drug administration and standing position was 44.9 ± 5.79 in IRG and 57 ± 9.88 min in IMG. In IRG, maintenance of SpO₂ values is >95% at each time point. Median and range peak of sedation {7 (5)} in IMG occurs at 20th, 25th, and 30th minutes post drug administration while was lower in IRG. Cardiorespiratory values were slightly lower in IMG than in IRG, but always constant in both treatments. Temperature did not differ between groups. At this dosage, although sedation score was higher in IMG, intrarectal route could be efficacious for performing minimally invasive clinical and diagnostic procedures in cats.

Sedation quality of alfaxalone associated with butorphanol, methadone or pethidine in cats injected into the supraspinatus or the quadriceps muscle

OBJECTIVES

The aim of this study was to compare the quality of sedation with three different anaesthetic protocols (alfaxalone combined with butorphanol, methadone or pethidine) administered intramuscularly in cats, and to evaluate the influence of the injection site (between supraspinatus and quadriceps muscles) on the onset and quality of sedation.

METHODS

A total of 151 cats were selected for this study. Cats were sedated with alfaxalone (3 mg/kg) combined with either butorphanol (0.3 mg/kg; n = 50), methadone (0.3 mg/kg; n = 53) or pethidine (5 mg/kg; n = 48). The combination was injected intramuscularly into the supraspinatus (n = 79) or quadriceps muscle (n = 72). The data included a scoring system for the quality of sedation and physiological parameters, such as heart rate (HR), respiratory rate, body temperature and occurrence of mydriasis, monitored during the first 30 mins of anaesthesia.

RESULTS

The opioid associated with alfaxalone influenced the overall sedation score, the degree of myorelaxation, the occurrence of mydriasis and HR. The overall sedation score was poorer with butorphanol than with methadone (P = 0.008), and butorphanol induced a lower degree of myorelaxation than methadone (P = 0.013). The injection into the supraspinatus showed better qualitative results for sedation and a faster onset time (in about 3 mins) than that into the quadriceps (P <0.001). HR decreased from baseline (P <0.001) and over time (P <0.001), mainly in cats of the butorphanol-supraspinatus and pethidine-quadriceps groups (P = 0.004). The occurrence of mydriasis was lower after butorphanol than after methadone and pethidine (P = 0.025), while the incidence of side effects did not differ among groups.

CONCLUSIONS AND RELEVANCE

All three protocols provided a good quality of sedation and allowed performing the scheduled procedure. Moreover, the injection into the supraspinatus muscle showed superior results in all the qualitative scores of sedation and quicker onset time than that into the quadriceps muscle.

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.