• Respiratory—airway patency, respiratory rate, oxygen saturation
• Cardiovascular—heart rate, blood pressure, electrocardiogram
• Neuromuscular strength assessment
• Pain assessment
• Mental status assessment
• Presence of nausea/vomiting
• Temperature measurement
• Urine output measurement
• Examination of surgical site for any drainage/bleeding
A physician then discharges the patient from the PACU
Postoperative Discharge and Bypass Criteria
Recovery of a patient begins from the end of intraoperative care, until the patient returns to the preoperative physiological state, that is, the resumption of normal daily activities. Patient recovery from anesthesia has traditionally been divided into three phases:
Early recovery (phase I): awakening and recovery of vital reflexes
Intermediate recovery (phase II): discharge from recovery room and home readiness
Late recovery (phase III): full recovery including psychological recovery with resumption of normal daily activities
Several scoring criteria have been used to assess patients’ early recovery, including the Aldrete scoring system and its modifications, the Mayo modified discharge score, and the standardized PACU Bypass/Discharge criteria. Table 41.2 lists a comprehensive PACU Discharge/Bypass scoring system that incorporates heart rate, pain, post operative nausea and vomitting (PONV), temperature, and surgical bleeding with the traditional discharge criteria.
Table 41.2
Comprehensive PACU scoring criteria that can be used for both PACU phase I discharge and phase I bypass
A score ≥ 18 is required for PACU discharge/bypass with no category with a score of 0 |
• Physical activity (excludes extremity with peripheral nerve block) |
A. For cases done using Monitored Anesthesia Care or General Anesthesia |
2 = Able to move all extremities (or return to baseline motor function) |
1 = Some weakness in movement of extremities |
0 = No movement |
B. For cases done using Central Neuraxial Anesthesia |
2 = Gross motor movement of all four extremities (or return to baseline motor function) with return of sensory level to L5 |
1 = Two segment regression of central neuraxial anesthesia and return of sensory level to L1 |
0 ≤ two segment regression of central neuraxial anesthesia or sensory level above L1 |
• Level of consciousness 2 = Fully awake 1 = Arousable with verbal or tactile stimulation 0 = Unresponsive |
• Blood pressure 2 = Systolic blood pressure ± 20 % of preanesthetic level 1 = Systolic blood pressure ± 21–30 % of preanesthetic level 0 = Systolic blood pressure ± > 30 % of preanesthetic level |
• Heart rate 2 = 60–100 or if outside this range, ≤10 % change from baseline HR 1 = HR outside the range of 60–100 and the change from baseline is >10 % and ≤20 % 0 = HR outside the range of 60–100 and the change from baseline is >20 % |
• Oxygen saturation 2 = SpO2 ≥ 92 % on room air or on supplemental oxygen with IV PCA 1 = SpO2 ≥ 92 % on supplemental oxygen not involving IV PCA 0 = SpO2 < 92 % on supplemental oxygen |
• Respiration 2 = Able to breathe or cough freely 1 = Shallow breathing or coughing, maintains airway without support 0 = Apnea, dyspnea, tachypnea (RR > 24) or bradypnea (RR < 8), or requires airway support |
• Pain 2 = No or mild pain with or without analgesics 1 = Moderate pain controlled with analgesics 0 = Persistent severe pain uncontrolled with analgesics |
• Postoperative nausea/vomiting 2 = No or mild nausea with no active vomiting 1 = Moderate nausea or transient vomiting 0 = Persistent severe nausea or vomiting |
• Temperature (tympanic) 2 = 36.0 °C to 38.0 °C 1 = 35.5 °C to 35.9 °C or 38.1 °C to 38.3 °C 0 = < 35.5 °C or > 38.3 °C |
• Bleeding 2 = Dry dressing, no drainage or oozing 1 = Minimal oozing or drainage 0 = Active bleeding, blood soaked surgical dressing, surgical drains filling with blood |
Oral Intake and Voiding
The ASA Practice Guidelines for PACU Care specifically state that the requirement that patients drink clear fluids and urinate before discharge should not be part of a routine discharge protocol. Depending on the type of surgery, patients who are awake and free of nausea can have ice-chips, water, or clear juice (apple, cranberry). If the patients tolerate these fluids well, they can be offered crackers, jelly, or even a light sandwich.
Although patients need not void urine before discharge, they should be instructed to come back to the hospital if they do not void in about 8 h. Patients who have received long-acting neuraxial blockade or have undergone procedures that may interfere with urinary function, should be discharged from the PACU until they can void satisfactorily. Risks factors for postoperative urinary retention include the type of surgery (urinary tract, anorectal, pelvic surgery), old age, spinal or epidural anesthesia, and prolonged surgery.
Discharge Criteria After Regional Anesthesia
Regional anesthesia is being utilized with increasing frequency in the ambulatory setting as it offers improved pain control, decreased risk of nausea and vomiting, and faster discharge times. Discharge criteria after spinal/epidural anesthesia include
Stable vital signs
Adequate hydration
Resolution of the block: normal perianal pinprick sensation (S4-5), plantar flexion of the foot, and proprioception of the big toe. For spinal anesthesia which is not resolving after 6–8 h, an epidural hematoma should be ruled out (urgent surgical decompression)
Peripheral nerve blocks: patients can be discharged before full resolution of the block, and instructed to take care of their insensate limb by using crutches to ambulate, elevate the limb to avoid swelling, and take analgesics as soon as the numbness starts to subside and a tingling sensation is felt in the limb
PACU Discharge Delay
Factors that can delay discharge from the PACU include
Increasing age, obesity
Long duration of surgery with general anesthesia
Bleeding and surgical complications
Presence of pain
Nausea & vomiting (female sex, history of postoperative nausea, opioids, longer duration of surgery, laparoscopic surgery, middle-ear surgery)
Sore throat (ETT > LMA, female sex, younger age, GYN surgery, use of succinylcholine)
lack of escort
Complications-cardiovascular, respiratory, or neurological
Fast-Tracking
With the rapid rise in ambulatory surgeries and the introduction of short acting anesthetics, it was recognized that criteria for early recovery from anesthesia were frequently met in the operating room, before patients were even transported to the PACUs. Therefore, criteria for bypassing (also called fast-tracking) phase I recovery were established to identify patient eligibility for PACU bypass, including the White and Song fast-tracking criteria and the Wake scoring criteria. These criteria if used by the anesthesia team after patient emergence can avoid unnecessary transfer of patients to the PACU if bypass criteria are met and have the following benefits:
Reduce the “bottlenecks” that occur as a result of routine transfer of patients to phase I recovery areas
Reduce PACU nursing staff workload (and the associated high nursing to patient ratio of 1:2)
Avoid the delays that occur as a result of transfer of patients from phase I to phase II areas
Improve patient satisfaction by reducing the number of postoperative “stations” before patient discharge
Reduce the need for PACU recovery for patients undergoing inpatient surgeries with a disposition to monitored surgical floors.
PACU Bypass Protocols
Several studies have reported that the implementation and application of protocols for PACU bypass coupled with multidisciplinary education increases PACU bypass success. The lack of uniform PACU bypass/fast-track eligibility criteria across studies and the use of different outcomes measures to compare anesthetic techniques have complicated the interpretation of the results of these trials.
In addition to PACU bypass eligibility, other outcome measures have included mortality, morbidity (pain scores, PONV), time to discharge, unanticipated hospital admission, hospital readmission, and patient satisfaction. Table 41.3 lists a summary of the factors that are likely to increase PACU bypass eligibility.
Table 41.3
Factors likely to increase PACU bypass eligibility for patients undergoing elective noncardiac surgery
• Identification and management of preoperative comorbidities of the patient |
• Preoperative identification of patients for whom fast tracking is not suitable (fast-track ineligible) |
• Use of evidence-based prophylactic therapies to reduce PONV (steroids, serotonin antagonists, transdermal scopolamine) |
• Multidisciplinary service specific (e.g., orthopedic/plastics) pathways/protocols |
• Continuous education for patients and the health care team: clear preoperative instructions for patients when and who to contact, helps sets expectations, reduces patient anxiety and increases their satisfaction |
• Multimodal approach to acute pain management including local anesthetic infiltration, peripheral nerve blocks, acetaminophen, nonsteroidal anti-inflammatory agents, low dose ketamine, and parenteral and oral narcotics |
• Utilization of anesthetic techniques that optimize surgical conditions while ensuring rapid recovery with minimal side effects (a) Monitored anesthesia care/general anesthesia: – Is endotracheal intubation necessary? – Is muscle relaxation required? – Use short acting agents: Benzodiazepines: midazolam Synthetic narcotics: fentanyl, alfentanil, remifentanil Anesthetic agents: Propofol, sevoflurane, desflurane Muscle relaxants: rocuronium, vecuronium, cisatracurium (b) Central neuraxial anesthesia: – Short acting local anesthetics: mepivacaine, lidocaine, or low dose bupivacaine – Hypobaric solutions for unilateral anesthesia (c) Peripheral nerve blocks: surgical anesthesia vs postoperative analgesia |
• Checklist for fast-track eligibility utilized in the operating room by the anesthesia team after patient emergence |
Postoperative Complications and Their Management in the PACU
Airway Management
Airway management is often challenging in the PACU. Factors that contribute to these difficulties include surgery close to the airway (cervical spine), intraoperative airway instrumentation or manipulation, previous neck dissection or radiation, prolonged surgery in the prone position, large volumes of intraoperative fluids, and residual anesthetic effects. Even patients considered as having an “easy airway” in the operating room can pose airway challenges in the PACU.
Airway Obstruction and Hypoxemia
Promptly restoring airway patency reduces the likelihood of negative pressure pulmonary edema and, more importantly, prevents O2 desaturation and hypoxemia. Oxygen supplementation during patient transfer to the PACU is reasonable for all patients. It is important to know that the hypoxic drive is inhibited by minimal residual concentrations of inhalational anesthetics.
The most common cause of postoperative airway obstruction is pharyngeal obstruction by the tongue. Simple interventions such as rousing the patient with gentle stimulation, jaw thrust, and, if necessary, insertion of a nasal or oral airway may restore airway patency. Persistence of airway obstruction or signs of laryngospasm mandate the application of positive pressure ventilation with oxygen via a bag and mask. Small doses of succinylcholine (20–40 mg) may also be necessary to relieve laryngospasm.
Patients with stridor may require treatment with nebulized racemic epinephrine and may benefit from a helium/oxygen mixture (70 % helium, 30 % oxygen), which reduces airway resistance and work of breathing relative to oxygen or air. Quick recognition of problems is necessary because stridor may advance to total airway obstruction.
Persistent hypoxemia after restoration of airway patency requires evaluation of possible etiologies (Table 41.4). In negative-pressure pulmonary edema, inspiratory efforts against an obstructed airway can cause alveolar-capillary membrane injury. Such a capillary leak may lead to respiratory failure requiring mechanical ventilation with positive end-expiratory pressure. The most common cause of hypoxemia (PaO2 < 60 mmHg) in the PACU is an increase in right to left shunting (most often from atelectasis). Other common etiologies include pulmonary aspiration and pulmonary edema. An unrecognized pneumothorax, perhaps caused by high inflation pressures during attempts to ventilate the patient, may lead to hemodynamic compromise and render resuscitation attempts difficult.
Table 41.4
Causes of postoperative hypoxemia
Mechanism | Examples | Alveolar–arterial O2 gradient | Response to 100 % O2 |
|---|---|---|---|
Decreased partial pressure of inspired oxygen | Hypoxic gas mixture, high altitude | Normal | Increased Pao 2 |
Hypoventilation | Obesity–hypoventilation syndrome, neuromuscular disorders, sleep apnea | Normal | Increased Pao 2 |
Ventilation–perfusion mismatch | COPD, asthma, interstitial lung disease | Increased | Increased Pao 2 |
Shunt | Pulmonary edema, ARDS, atelectasis, pneumonia, pneumothorax | Increased | Minimal if any increase in Pao 2 |
Diffusion impairment | Pulmonary embolism | Increased | Increased Pao 2 |
Hypoventilation
Postoperative hypoventilation and apnea can be caused by residual neuromuscular blockade, as a result of overdose, inadequate reversal dosing, hypothermia, or metabolic factors (hypokalemia, hypocalcemia), which are factors that interfere with adequate reversal.
Opioid-induced respiratory depression is also a frequent cause of postoperative hypoventilation. Opioids not only shift the carbon dioxide response curve to the right (i.e., raise the apneic threshold), but can also decrease the slope of the carbon dioxide response curve (i.e., reduce the minute volume response to a high PaCO2) in anesthetized patients (the slope of the carbon dioxide response curve is unchanged by opioids in fully awake patients). Splinting resulting from incisional pain can also cause postoperative hypoventilation.
Airway Management After Cervical Spine Surgery
Patients undergoing surgery for cervical spine disease have a greater incidence of difficult intubation than do matched control subjects. Airway complications are common after anterior cervical spine surgery and range from acute airway obstruction (1.2 %) to chronic vocal cord dysfunction. Risk factors associated with airway obstruction after cervical spine surgery include
Advanced age
Obesity (weight >100 kg)
Exposure of three or more vertebral bodies or exposure of C2, C3, or C4
Estimated blood loss greater than 300 ml
Transfusion of four or more red cell units
Operative time more than 10 h
Combined anteroposterior cervical spine surgery
Severe preoperative neurologic deficits
Airway complications may also occur after cervical spine surgery in the prone position, most commonly due to macroglossia and laryngeal edema. Decreased venous return from the face and upper neck is the likely etiology. A plan for reintubation should be in place before any extubation attempts. The presence of external stabilization devices complicates airway management. Removal of the anterior part of a cervical collar during reintubation attempts improves airway visualization, but should be accompanied by manual inline stabilization in patients with an unstable cervical spine. Manual inline stabilization reduces cervical spine motion during intubation attempts in patients with an unstable cervical spine.
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