Post-anesthetic care

1

Which patients should be cared for in the postanesthetic care unit?

According to American Society of Anesthesiologists standards, all patients who have received an anesthetic of any kind shall receive postanesthetic management of some kind. Postanesthetic care unit (PACU) care is traditionally divided into phase 1, which is functionally analogous to an intensive care unit, and phase 2, wherein transition is made from intensive observation to preparation for care on a surgical ward or at home.

Fast-track recovery is emerging because of fast-offset anesthetic agents and adjunctive drugs. Most patients who have sedation and/or extremity regional anesthesia should be appropriate for fast-track recovery, in which phase 1 care is bypassed. Coexisting disease, the surgical procedure, and pharmacological implications of the anesthetic agents used, ultimately determine the most appropriate sequence of postoperative care for each patient.

2

Review the important considerations for the immediate postanesthetic phase of care.

Transport from the operating room (OR) to the PACU can be a dangerous time for patients. Anesthetics conducted remote from the PACU (e.g., radiology) are also a site of potential instability. For this reason, it is standard practice for patients to be transported by a member of the anesthesia care team who has knowledge of the patient and can continuously assess their condition. Before transport to the PACU from remote locations, a patient should have oxygen administered, and be able to maintain a patent airway with spontaneous respirations. The use of supplemental oxygen for transport is recommended. Patients with hemodynamic or respiratory instability will require the use of a transport monitor and ventilatory equipment.

3

Describe the process for PACU admission

A report is given by the anesthesia caregiver to the PACU nurse, reviewing the patient's prior health status, surgical procedure, intraoperative events, agents used, and anesthetic course.

The use of muscle relaxants and their reversal, interventions for analgesia, and intraoperative fluids, and blood products administered guide PACU care.

Initial assessment of the patient by the PACU nurse includes vital signs, baseline responsiveness, adequacy of ventilation, and adequacy of analgesia. Various scoring systems have been used to allow numeric scoring of subjective observations as an indicator of progress toward discharge. The Aldrete scoring system ( Table 34.1 ) tracks five observations: activity, respiratory effort, circulation, consciousness, and oxygenation. Scales for each are 0 to 2, and a total score of 8 to 10 indicates readiness to move to the next phase of care. Regression of motor block in the case of regional anesthesia is also an important determinant of readiness for discharge, particularly when discharge home is planned.

4

What monitors should be routinely used in the PACU?

Pulse oximetry and periodic blood pressure monitoring should be used routinely on all patients. Routine electrocardiogram (ECG) monitoring should be done in most patients. Finally, temperature, urine output, and surgical drainage require monitoring as appropriate.

5

What problems should be resolved during postanesthetic care?

• Hypoventilation: The patient should be breathing easily and able to cough on command. Oxygenation status should return to near preanesthetic levels.

• Hemodynamic stability: Blood pressure should be within 20% of preanesthetic measurements, with a stable heart rate and rhythm.

• Attenuated sensorium: The patient should be fully awake and voluntarily move all extremities.

• Postoperative pain: Pain management should no longer require continuous nursing intervention.

• Postoperative nausea and vomiting (PONV): PONV should be treated aggressively, because it is associated with prolonged length of stay in the PACU and decreased patient satisfaction with the perioperative experience.

6

Describe the appearance of a patient with residual neuromuscular blockade.

Residual neuromuscular blockade (NMB), opioid effects, and lingering effects of inhalational anesthesia all can result in postoperative hypoventilation ( Table 34.2 ). Patients with residual NMB are frequently described as appearing floppy, exhibiting poorly coordinated and ineffective respiratory muscle activity. The patient may complain that breathing is restricted and efforts to deliver supplemental oxygen are suffocating. Oftentimes, they are unable to sustain a head lift or hand grasp. In the worst case scenario, weakness of the pharyngeal muscles results in upper airway collapse and airway obstruction. Of note, neither a good response to train-of-four testing in the OR nor spontaneous rhythmic ventilation before extubation rules out residual NMB.

7

How do opioids and residual volatile anesthetics affect breathing?

Slow rhythmic breathing or apneic pauses in a patient who is hard to arouse suggest the presence of residual opioids and/or volatile anesthetics. In contrast to patients with residual NMB, these patients are often unconcerned about ventilation despite obvious hypoxia. In fact, surprising degrees of hypercapnia may be found, even while the pulse oximetry values remain relatively normal. This phenomenon is usually observed when patients are hypoventilating, while receiving supplemental oxygen, thereby enabling their pulse oximetry (SpO ₂ ) values to remain normal (see later).

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