It's not over yet: the recovery period
WASHINGTON, DC – According to a large scale U.K. veterinary study the greatest risk for anesthetic-related death occurs during the post-operative period.1 This indicates the importance of continuing to monitor and manage veterinary patients during the recovery period, explained Darci Palmer BS, LVT, VTS (Anesthesia & Analgesia), speaking at the International Veterinary Emergency and Critical Care Conference.
The recovery phase begins once the procedure is complete and anesthesia is discontinued. Recovery should be smooth, rapid, and stress-free for the patient. The recovery area should be quiet with the lights dimmed to help prevent unnecessary stimulation.
Ms. Palmer stressed the importance of having a designated technician or trained assistant stay with the patient at all times until extubation occurs. An unassisted patient can easily wake up and bite the endotracheal tube without warning.
Extubation
Once the patient is in recovery, the oral cavity should be inspected for any signs of regurgitation or the presence of residual blood or foreign material from surgical or dental procedures. The inhalant should not be turned off until the oral cavity has been examined and cleared and the cuff should not be deflated until the patient has regained the ability to swallow and protect its own airway. In dogs, extubation should occur when the patient is showing multiple signs of regaining consciousness (e.g., multiple swallows, attempting to lift head from table, moving or stretching a limb, etc). In cats it should occur at the earliest sign of regaining consciousness (e.g. swallowing, ear or whisker twitch, brisk palpebral or voluntary movement of head or tail, etc). Prolonged extubation in cats could lead to laryngospasm.
Dogs and cats are more easily recovered in lateral recumbency. However, brachycephalic breeds should be recovered in sternal recumbency with their head and neck extended to open up the airway. Extubation is often delayed in brachycephalic breeds to ensure they are conscious enough to maintain a patent airway.
Gastroesophageal reflux
Gastroesophageal reflux (GER) is a common occurrence in anesthetized patients, and it usually goes unnoticed because no clinical signs are apparent. If the refluxed gastric content reaches the pharynx it is called regurgitation. If a significant amount of regurgitation is present it puts the patient at a higher risk for lung aspiration. If brown or yellowish fluid is seen coming from the patient’s mouth and/or nose, it should be remedied prior to extubation.
Monitoring
Monitoring is extremely important throughout all phases of anesthesia and should continue into the post-operative period. It is beneficial to continue monitoring ETCO2 until extubation as this will help detect hypoventilation. If an arrhythmia was present during anesthesia then it would be advantageous to continue monitoring with an ECG.
At a minimum, the vital signs should continue to be monitored and recorded on the anesthesia record every 5 minutes for every patient until extubation has occurred. If a Doppler was used during anesthesia then it should be left attached to the patient so an audible pulse can be heard during recovery at all times.
A full recovery is often defined as the point when the patient is able to sit sternal (if the condition allows) and all vital signs are within normal limits.
Even if a patient is extubated, they should be watched closely and assessed every 15-20 minutes until a full recovery has been achieved. Supplemental oxygen may be required if a patient is unable to maintain normal oxygen saturation. It is recommended that the IV catheter remain in place until the patient has made a full recovery and pain management has been adequately addressed.
Ms. Palmer said that hypothermia is a very common complication after an anesthetic procedure and must be addressed in the recovery period. Any patient that has a temperature below 37.3°C should be covered with warm blankets and supplied with a heat source until the temperature has increased. The temperature should continue to be monitored every 15-20 minutes, depending on the patient’s temperament. Once the temperature is within normal range the heat source should be removed and the patient checked after about an hour to ensure that body temperature can be maintained.
As well, appropriate nursing care is important during the recovery phase. Unless it is contraindicated, the bladder should be expressed before the inhalant is turned off to improve patient comfort in the post-operative period. The patient should be placed on soft bedding and padding and if the bedding becomes soiled it should be changed immediately. The incision site should be cleaned of any residual blood or scrub solution after surgery and be kept clean and dry at all times. Food and water should be offered as soon as it is deemed appropriate by the veterinarian.
Post-operative pain management
Patients recovering from a surgical procedure should be assessed for pain as soon as they are conscious, and every hour for the first few hours after recovery. Observation should continue on a regular basis until the patient is discharged from the hospital.
When a patient is under general anesthesia the vital signs are reliable indictors of pain; however, when a patient is conscious it is more beneficial to assess behavioural signs to determine the degree of pain. Signs include anxiety level, vocalization, body position, reluctance to move or lie down, facial expressions, general appearance, and response to manipulation or palpation.
While there is no ‘gold standard’ to help assess animal pain, pain scales have been developed that take into account behavioural signs. Every veterinary clinic should have a consistent way to evaluate and assess animal pain.
An analgesic plan should be implemented to address acute pain for the first 24-48 hours. For patients undergoing a major invasive procedure it is common to keep them in the hospital and maintain them on an opioid continuous rate infusion for the first 24 hours post-surgery. Additional drugs such as NSAIDs, local anesthetics, ketamine, and dexmedetomidine can be added as part of the multi-modal analgesia protocol.
Rough recoveries
Ms. Palmer explained that despite our best efforts, there will be times when a patient wakes up and displays a rough recovery, often characterized by excessive vocalization, paddling their legs, head bobbing or head thrashing, agitation, and disorientation.
She said that since it can be difficult to predict when this will happen, having a plan ahead of time is recommended for every patient. Before the inhalant is turned off, the anesthetist should evaluate the anesthesia record to determine the time that analgesic and sedative drugs were given in the premedications and if/when additional doses were administered. If the duration of action of the analgesic and sedative agent has been exceeded then additional doses should be available during recovery.
Because our patients cannot verbally communicate with us it is often difficult to determine if a rough recovery is due to pain or anxiety. Therefore, it is better to treat with an analgesic drug (pure mu opioid) and sedative agent together rather than give either drug alone.
Emergence delirium is defined as a dissociated state of consciousness in which the patient is unaware of their surroundings. It is commonly seen when no sedation is on board during recovery. Patients can display excitement, agitation, restlessness, and vocalization. Appropriate monitoring of the patient and prompt treatment is required if present.
Dysphoria has been described as causing agitation, excitement, restlessness, excessive vocalization, and disorientation. Dysphoria is the least likely cause of a rough recovery and is seen only when excessively high dosages of opioids are utilized. A vocal patient should be assessed for pain and emergence delirium before labeling the patient dysphoric.
Reference
1. Brodbelt, DC, et al., Vet Anaesth Analg 2008;35(5):p.365-73.CVT
