Anesthetic recovery is a critical phase of the perioperative period that requires as much planning and monitoring as induction and maintenance. Many veterinary professionals feel relieved as pets awaken from anesthesia as planned, but complications can occur during this period.
When complications arise during anesthetic recovery that are attributable to particular drugs or when patients experience a prolonged recovery, reversal agents can help. However, teams using these drugs should be familiar with their capabilities and when to use them.
Here is a refresher on what to expect during the anesthetic recovery period, the risks to patient health during this time, the role of reversal agents in recovery, and best practices to ensure patient safety.
Key Takeaways
- Between 47% and 60% of anesthetic complications occur during the recovery period, necessitating close monitoring and quick interventions.
- Reversal drugs can aid in patient recovery by addressing drug-specific complications, speeding up prolonged recoveries, or smoothing rough recoveries.
- Drug reversal is not always indicated, and teams should consider a pet's pain status and behavioral state before deciding if other interventions are more appropriate.
Anesthetic Recovery Risks and Complications
While veterinary anesthesia-related mortality is low in healthy patients, the recovery phase carries significant risk for morbidity if not actively managed—between 47% and 60% of complications occur during this time.
Responses to anesthetic drugs may result in the following during recovery:
- Hypothermia
- Bradycardia
- Hypoventilation
- Hypotension
- Delayed arousal
Behavioral complications, including emergence delirium, anxiety, and dysphoria, may also occur during the post-op period. Patients with a reduced ability to metabolize drugs, including pediatric and geriatric populations, are at a higher risk of these complications.
What Causes Rough Recoveries?
Anesthetic drug protocols can influence recovery quality. Agents like ketamine and tiletamine-zolazepam can increase the risk of a rough recovery as they often remain in effect after other drugs have worn off. Balancing protocols with adequate sedation and analgesia can help.
However, even the most well-constructed anesthetic protocol can lead to a rough recovery, often characterized by vocalization, paddling, head thrashing, or agitation. Causes include pain, emergence delirium, and dysphoria, but determining which of these is responsible for the patient's behavior is critical in selecting an appropriate treatment.
In addition to physiologic factors like patient age and drug selection, a patient's temperament and anxiety level before the procedure can also influence the quality of recovery. Those patients with a history of rough induction or recovery are likely to experience the same issue again.
Addressing a Rough Anesthetic Recovery
When patients emerge from anesthesia vocalizing or thrashing, address the problem by first identifying the cause:
- Pain — Consider whether the patient received adequate pain control. If not, treat the pain and re-assess the patient. If the issue persists, consider whether emergence delirium or dysphoria is to blame.
- Emergence Delirium — Emergence delirium is a dissociated state of consciousness while transitioning out of anesthesia. Reversing certain agents or administering a sedative, such as dexmedetomidine or acepromazine, can usually calm these patients.
- Dysphoria — Dysphoria is often a side effect of opioids. Dysphoric patients do not respond to human attempts to soothe them and may get worse if given additional painkillers. Instead, sedative medications or opioid reversal can help restore calm behavior.
Overview of Reversal Agents
Reversal agents are used to counteract the effects of specific sedatives or analgesics. The most commonly used reversal drugs in veterinary care include:
- Atipamezole — Reverses the effects of alpha-2 agonists dexmedetomidine and medetomidine after IM administration.
- Naloxone — Reverses opioid effects, including analgesia. Generally reserved for opioid-induced dysphoria or overdose and should be used cautiously in painful patients.
- Butorphanol — Can partially reverse the effects of stronger opioids and provide mild pain relief.
- Flumazenil — Reverses benzodiazepines in patients experiencing dysphoria or excitation from these drugs.
Not all anesthetic drugs have a reversal agent, and reversal isn't appropriate for all patients. Teams must assess each patient during recovery to determine if reversal agents are appropriate.
When to Use Reversal Drugs in Veterinary Care
Reversal agents are most commonly used for short procedures requiring heavy sedation, such as wound care, imaging, or examinations in fearful or anxious pets. Alpha-2 agonists like dexmedetomidine provide sedative, anxiolytic, and analgesic effects that are quickly reversible with atipamezole, allowing pets to go home soon after their procedures.
Reversal agents are also helpful during anesthesia maintenance or recovery, particularly when recovery is prolonged or if complications develop. Alpha-2 agonists, benzodiazepines, and opioids given during the pre-operative or intra-operative periods can be wholly or partially reversed to address negative effects, such as bradycardia or hypotension.
However, teams must consider the effects of reversing drugs that provide pain relief. In painful patients or those likely to have post-operative pain, veterinarians should administer an alternate analgesic agent before reversal to avoid an abrupt and painful awakening.
Anesthetic Recovery Monitoring and Planning
Veterinary team members should continue to monitor heart rate, respiratory rate, temperature, mucous membranes, and level of consciousness during recovery until the patient is extubated, their vitals stabilize, and they are resting comfortably in the recovery area.
Hypothermia, bradycardia, and airway obstruction are common complications during the recovery period, as are pain, emergence delirium, and anxiety. Meticulous patient monitoring and intervention during this time are critical. Administering additional analgesics or microdoses of sedatives can help smooth recovery in pets that experience distress upon awakening.
Planning for recovery begins during the development of the anesthetic plan. Drug doses for reversal agents and emergency drugs should be calculated before induction so that team members can act quickly if reversal becomes necessary.
Reversal Drugs in Safe Anesthetic Recovery
Veterinary anesthesia is safe for most pets. However, pets remain at continued risk of complications during the anesthetic recovery period, requiring teams to anticipate potential issues and prepare for them in advance. Close monitoring and the use of reversal drugs in veterinary care can ensure safe anesthesia and patient comfort.
Parnell manufactures safe and effective sedative and reversal agents for small animals. Parnell Brand Dexmedetomidine Hydrochloride Injection and CONTRASED™ (atipamezole hydrochloride) pair well to provide fast, reliable sedation and reversal across a variety of clinical scenarios.
To learn more about anesthesia basics, including sedation, pre-medication, and reversal drugs in veterinary care, check out our certificate course, Foundations of Anesthesia and Sedation. For information on our product portfolio, including CONTRASED, contact us here.
