Just a Quick Stitch-Up-Procedural Sedation Made Easy
Gianluca Bini, DVM MRCVS DACVAA
Procedural sedation plays a crucial role in veterinary medicine, allowing safe and effective
management of patients undergoing minor procedures. Various drug options exist, each with unique effects, advantages, and risks. This lecture provides an overview of available sedative drugs, their mechanisms, side effects, and best practices for safe and effective sedation.
SEDATION - DRUG OPTIONS AND CONSIDERATIONS
1. Alpha-2 Adrenergic Agonists
Effects: Sedation, analgesia, muscle relaxation.
Reversible: Yes (Yohimbine, Atipamezole).
Common Drugs:
o Xylazine: Onset 3-5 min IV; duration up to 30 min.
o Detomidine: Onset 40 min; duration up to 3 hours.
o Romifidine: Onset 3-5 min IV; duration 1-2 hours.
o Medetomidine: Onset 2-10 min; duration 1 hour.
o Dexmedetomidine: Onset 2-10 min; duration 1 hour.
Side Effects: Biphasic vasoconstriction/vasodilation, bradycardia, respiratory depression, increased urine production, decreased ICP.
Medetomidine/Vatinoxan Combination:
o Vatinoxan counteracts peripheral cardiovascular effects.
o Used only for procedural sedation (not premedication).
2 Opioids
Pure Mu-agonists: Provide strong analgesia.
o Hydromorphone: 0.1 mg/kg IV/IM, lasts ~2 hours – may cause vomiting.
o Methadone: 0.1-0.5 mg/kg IV/IM, lasts ~3-4 hours.
o Morphine: 0.1-0.5 mg/kg IV/IM, lasts ~3-4 hours – may cause vomiting.
o Fentanyl: 3-5 mcg/kg IV/IM, lasts ~15-20 minutes.
Partial Mu-agonist: Buprenorphine (20-30 mcg/kg IV/IM, lasts 6-8 hours).
Kappa Agonist/Mu Antagonist: Butorphanol (0.1-0.5 mg/kg IV/IM, lasts 45 minutes).
Side Effects: Bradycardia, respiratory depression, nausea, vomiting (especially
Morphine, Hydromorphone).
3. Benzodiazepines (Midazolam)
Effects: Facilitates GABA on GABA A receptors.
Does not induce anesthesia
Does not provide analgesia.
Potential for excitement in dogs, cats, and horses (may be dangerous).
Minimal cardiovascular effects but respiratory depressant when combined with other
drugs.
Dose: 0.1-0.5 mg/kg IM/IV (SA/LA), 2 mg/kg IM (pet birds).
4. Alfaxalone
GABA A agonist – Can induce anesthesia.
Does not provide analgesia.
Respiratory and cardiovascular effects similar to propofol.
IM or IV administration possible:
o Sedation (Dogs/Cats): 2 mg/kg IM.
o Induction (Dogs/Cats): 2-5 mg/kg IV.
Advantage over Propofol: IM administration possible.
5. Ketamine
NMDA antagonist – Can induce anesthesia with moderate analgesia.
Minimal respiratory depression and increases heart rate.
Dose and Administration:
o Sedation: 2 mg/kg IM with alpha-2 agonist + opioid in aggressive patients.
o Induction: Dogs/Cats 5-10 mg/kg IV, Horses 2.5 mg/kg IV.
o Must be paired with a muscle relaxant (midazolam 0.3 mg/kg IV) if inducing
anesthesia.
EXAMPLES OF SEDATION PROTOCOLS
Non-Painful Procedures
Dexmedetomidine: 5 mcg/kg IM or 1-2 mcg/kg IV.
Butorphanol: 0.2-0.3 mg/kg IM/IV (lasts 45 min).
If the patient is aggressive add:
Ketamine (1-2 mg/kg IM).
Painful Procedures
Dexmedetomidine: 5 mcg/kg IM or 1-2 mcg/kg IV.
Add one of the following opioids:Methadone: 0.2-0.3 mg/kg IM/IV (lasts 3-4 hours).
Hydromorphone: 0.1 mg/kg IM (lasts 2 hours).
Fentanyl: 3-5 mcg/kg IM (lasts 30 minutes).
If the patient is aggressive add:
Ketamine (1-2 mg/kg IM).
Sedation for “Sicker” Patients
Alfaxalone (2 mg/kg IM) + Midazolam (0.2 mg/kg IM).
Add one of the opioids mentioned above.
Alternative Combination for Aggressive Cats
Dexmedetomidine (5 mcg/kg IM) + Telazol (2.5 mg/kg IM).
Monitoring and Safety Considerations
Equipment:
o Pulse oximeter
o ECG monitor
o Blood pressure monitor
o Oxygen supply (mask, flow by is not able to provide O2 concentration higher
than room air)
o Laryngoscope and ET tubes ready for intubation
o Suction device
Monitoring Parameters:
o Respiratory rate
o Jaw tone, palpebral reflex, eye position
o Blood pressure and Pulse-Oximeter/ECG readings
Bradycardia Management:
o Atropine: 0.02 mg/kg IV.
o Glycopyrrolate: 5-10 mcg/kg IV (IM for prolonged effect).
Antinausea/Antiemetics:
o Maropitant (1 mg/kg IV).
o Ondansetron (0.5-1 mg/kg IV).
o Metoclopramide (1-2 mg/kg/day CRI).
o Cisapride (1 mg/kg PO q8h).
! NO PHARMACOLOGIC TREATMENT IS EFFECTIVE IN PREVENTING REGURGITATION !
Oxygenation:
o Oxygen flow-by is ineffective; a mask is preferred (achieves ~40% O2).
When is General Anesthesia Safer?
Patients with upper airway disease: Brachycephalic breeds, collapsing trachea.
Patients with lower airway disease: Pneumonia, bronchitis, asthma.
Patients with a history of regurgitation/GERD.
Non-fasted patients.
Optimizing Recovery
Provide a quiet recovery area.
Keep the IV catheter in place.
Fine-tune sedation:
o Acepromazine (10 mcg/kg IV) or dexmedetomidine (1 mcg/kg IV) if excessive arousal.
Monitor closely post-procedure.
CONCLUSION
Safe and effective procedural sedation relies on understanding drug options, their effects, and careful patient monitoring. Proper selection and combination of sedatives, along with close monitoring and preparedness for complications, enhance patient safety and procedural success.
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