Recovery From Anaesthesia
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Introduction
The post operative period is an important stage within an anaesthetic procedure, both immediately after the anesthetic and once the patient is back in wards/stables etc.
Immediately Post Anaesthetic
The primary concern after any anaesthetic procedure is to maintain the airway of the patient. Commonly after the anaesthetic agent is turned off, if inhalation agents have been used, or the infusion is stopped in cases of total intravenous anaesthetic procedures, the animal is then maintained on oxygen for a short period of time. If required, the anaesthetist can also ventilate the patient, if intubated, if they are not spontaneously breathing adequately. Once the patient is breathing spontaneously and has received sufficient oxygen to remove the anaesthetic agents from the respiratory 'dead space' and to allow the arterial oxygen tension to equilibrate to normal levels, the oxygen can be turned off and the patient allowed to breathe room air. This time on oxygen post-operatively is particularly important in patients that have received nitrous oxide during a procedure, or patients with known airway disease; oxygenation of these patients should be monitored closely with a pulse oximeter or, if available, blood gas analysis.
Endotracheal Tube removal
The time of endotracheal (ET) tube removal varies between species. In any patient, however, close monitoring should continue before and after removal of the ET tube. In dogs, it is possibly to leave the tube in until the dog is sitting in sternal as many dogs will tolerate ET tube placement; it can, however be removed when the patient is swallowing spontaneously. A delay in removing the tube can result in the patient chewing on the tube and damaging it. In cats, ET tubes should be removed before the animal becomes conscious to reduce the risk of laryngeal spasm which may result in laryngeal oedema and obstruction. In horses, ET tubes may be removed early to prevent damage, and a nasal tube can be placed to provide a supplementary oxygen if this is indicated.
Temperature
One concern with patients undergoing anaesthesia is hypothermia; it is important to monitor the temperature of patients during and after any anaesthetic. If necessary, techniques to try and prevent further temperature loss and to try warm up the patient can be instigated as soon as possible. Indirect heat sources such as 'hot hands' (examination gloves filled with hot water and tied off with a knot at the wrist) placed between the patient and a towel, for example are required for heating the patient that is slightly hypothermic, and preserving heat loss from the extremities by insulating the limbs with 'bubble wrap' will all help to maintain the patient's core temperature. Never use a direct heat course as the animal is not able to move away from the heat and can potentially sustain tissue burns as a result.
Post Operative Analgesia
Post operative analgesia is often forgotten but it of great importance in any anaesthetic procedure. A variety of agents can be used systemically or locally. The patient should be closely monitored after the procedure and pain assessed regularly to adjust the analgesic protocol appropriately.