Recommend fasting before anesthesia to reduce the risk of regurgitation and aspiration, understanding that gastric emptying times vary widely among individual patients and with the contents of the food ingested.5 Young animals require shorter fasting times. Food should not be withheld for >4 hours before surgery for those from 6 weeks to 16 weeks of age because of the risk of perioperative hypoglycemia. Although there is evidence to suggest that shorter fasting times (<6 hours) might be sufficient to decrease the risk of regurgitation for those >16 weeks of age, overnight fasting is recommended for procedures scheduled earlier in the day.6
With emergency procedures, fasting is often not possible, thus attention to airway management is critical. Do not delay emergency procedures when the benefit of the procedure outweighs the benefit of fasting.
Diabetic patients may or may not be fasted depending on the veterinarian’s preference and anticipation of procedure time. Adjust insulin administration accordingly with food intake. Regardless of how the patient has been fasted, manage the airway of every patient as if its stomach were full.
Create an individualized plan for patient management based on the anesthetic risks identified in the preanesthetic evaluation, understanding that no single plan is appropriate for all patients. Resources such as staffing, equipment, and drug availability also influence plan development. A complete anesthetic plan addresses perioperative analgesia, pre- and post-anesthetic sedation and/or tranquilization, induction and maintenance drugs, ongoing physiologic support, monitoring parameters, and responses to adverse events. The plan should be flexible to allow for dynamic patient responses during anesthesia.
The advantages of preoperative sedation and analgesia include lowered patient and staff stress, ease of handling, and reduction of induction and inhalant anesthetic doses, most of which have dose-dependent adverse effects. There can be disadvantages to the administration of preanesthetic medications, such as dysphoria related to benzodiazepines, bradycardia related to α-2 agonists and opioids, and hypotension related to acepromazine. These disadvantages can be mitigated by appropriate dosing and selecting the right combination of drugs for the individual. Patients in critical condition may not require any premedication.
Choose drugs and techniques that provide both intraoperative and postoperative analgesia. Because there is a high variability in patient response to sedation and analgesia, individually tailor the med-ication type, dose, and frequency based on the anticipated intensity and duration of pain. In addition to opioid premedication, perioperative analgesic techniques include nonsteroidal anti- inflammatory drugs, local and regional nerve blocks, as well as IV infusions of opioids, N-methyl-d-aspartate receptor antagonists (e.g., ketamine), and/or lidocaine. Multiple analgesic techniques should be considered for more painful procedures. Frequently reassess patient comfort and adjust pain management as needed. The AAHA Pain Management Guidelines and many other sources provide descriptions of and suggestions for pain management f.7–9
Anesthetic management of patients with comorbidities
Certain conditions require modification of the anesthetic protocol. Extensive discussion of the anesthetic management of the diseased patient is beyond the scope of these guidelines. However, brief mention of diabetes, renal, cardiac, and hepatic disease is warranted.