Overview of post-anesthetic care for adult patients

INTRODUCTION — Timely recognition and management of issues that arise in the immediate postoperative period may be life-saving. The likelihood that a specific complication will arise for a given patient is determined by the nature of the procedure, the anesthetic techniques used, the patient's comorbidities, and preoperative medical assessment and optimization.

This topic serves as an overview for post-anesthetic care and the most common problems encountered in the post-anesthesia care unit (PACU). Preoperative evaluation and preventive strategies are discussed elsewhere. (See "Preoperative medical evaluation of the healthy adult patient" and "Management of cardiac risk for noncardiac surgery" and "Evaluation of perioperative pulmonary risk".)

PHASES IN THE POST-ANESTHESIA CARE UNIT — It is common practice for most patients who receive general anesthesia, regional anesthesia, or monitored anesthesia care to be monitored in a post-anesthesia care unit (PACU) prior to discharge from the hospital or transfer to a ward bed. The exception is critically ill patients and those who are intubated, who may bypass the PACU and be recovered directly in an intensive care unit (ICU). In most PACUs, medical oversight of patients is the responsibility of the anesthesiology service.

Initial handoff — The initial handoff from the anesthesia care team to personnel in the PACU is typically standardized, as shown in the examples (figure 1 and table 1). Further discussion is available in separate topics. (See "Handoffs of surgical patients" and "Patient handoffs".)

Phase I and II care — PACU care is typically divided into two phases. Phase I emphasizes ensuring the patient's full recovery from anesthesia and return of vital signs to near baseline. Phase II recovery focuses on preparing patients for hospital discharge, including education regarding the surgeon's postoperative instructions and any prescribed discharge medications.

ASSESSMENT, MONITORING, AND CARE

Initial assessment and care — Airway patency, respiratory rate (RR), peripheral oxygen saturation (SpO₂), heart rate (HR), blood pressure (BP), the electrocardiogram (ECG), mental status, temperature, and the presence of pain, nausea, or vomiting are assessed upon arrival in the post-anesthesia care unit (PACU) [1]. Neuromuscular function is also assessed by physical examination; a peripheral nerve stimulator may be employed for patients who remain intubated and received a neuromuscular blocking agent (NMBA) intraoperatively (see "Overview of the management of postoperative pulmonary complications"). Intake and output (eg, fluid administration, urine output, bleeding, wound drainage) are calculated shortly after arrival in the PACU to evaluate postoperative hydration status. (See "Intraoperative fluid management".)

Supplemental oxygen is administered to patients who received sedation or general anesthesia to avoid or treat hypoxemia in the PACU (table 2). Standard care also includes assessments and immediate treatment of postoperative pain (see "Approach to the management of acute pain in adults"), nausea or vomiting (see "Postoperative nausea and vomiting"), and temperature abnormalities (see 'Hypothermia or hyperthermia' below). Specific wound or dressing management ordered by the surgical team may be necessary after certain procedures (eg, ice packs, continuous bladder irrigation).

Assessment after neuraxial block — In addition to standard assessments, the degree of analgesic efficacy and gradual return of motor and sensory function are documented in patients who have received a neuraxial block. (See "Continuous epidural analgesia for postoperative pain: Technique and management", section on 'Monitoring during epidural analgesia'.)

Suspected complications of a neuraxial anesthetic, in particular spinal epidural hematoma (SEH), may require urgent assessment and treatment (see 'Spinal epidural hematoma' below). Other possible complications include transient neurologic symptoms, postdural puncture headache, backache, and urinary retention; these are discussed in detail in other topics. (See "Overview of neuraxial anesthesia", section on 'Adverse effects and complications' and "Adverse effects of neuraxial analgesia and anesthesia for obstetrics", section on 'Side effects'.)

Monitoring — After initial assessment and stabilization, RR, SpO₂, HR, and ECG are monitored continuously, while airway patency, BP, mental status, neuromuscular function, and temperature are frequently reassessed [1]. There are no evidence-based guidelines regarding frequency of vital sign monitoring in the PACU. Vital signs are typically obtained every five minutes for the first 15 minutes, then every 15 minutes for the duration of the Phase I period. Typically, HR and BP are maintained within approximately 20 percent of baseline values for the individual patient, while RR and SpO₂ are maintained as close to baseline levels as possible.

During Phase II recovery, vital signs are typically obtained every 30 to 60 minutes. For patients remaining in the PACU due to logistical reasons after discharge criteria have been met (eg, lack of inpatient bed availability or a ride home), vital signs are obtained only when indicated or at the same frequency employed in the hospital unit to which the patient will be transferred.

INCIDENCE OF COMPLICATIONS — A retrospective review involving 18,473 patients noted that the most common problem in the post-anesthesia care unit (PACU) is postoperative nausea and vomiting (9.8 percent) [2]. Other complications involved the upper airway (6.9 percent) or cardiovascular system (eg, hypotension [2.7 percent], dysrhythmias [1.4 percent], hypertension [1.1 percent], major cardiac events [0.6 percent]). In a 2002 review of 419 PACU incident reports from the Australian Incident Monitoring Study (AIMS), 44 percent were upper airway or respiratory complications, while 24 percent were cardiovascular complications [3]. An analysis of 43 closed malpractice claims against anesthesiologists that involved problems in the PACU occurring between 2010 and 2014 noted that 37 percent involved patient death [4]. Respiratory injuries (33 percent), airway injuries (12 percent), and nerve injuries (16 percent) accounted for most of the other complications.

POSTOPERATIVE NAUSEA AND VOMITING — Postoperative nausea and vomiting (PONV) is the most commonly treated problem in the immediate postoperative period. Control of PONV is a necessary criterion for discharge from the post-anesthesia care unit (PACU), regardless of whether the patient is going home or to a hospital ward. Risk factors, preventive strategies, and treatment of PONV are discussed separately. (See "Postoperative nausea and vomiting".)

RESPIRATORY COMPLICATIONS — Management of bronchospasm and/or anaphylaxis in the post-anesthesia care unit (PACU) is the same as management in the operating room (table 3). (See "Anesthesia for adult patients with asthma", section on 'Intraoperative bronchospasm' and "Perioperative anaphylaxis: Clinical manifestations, etiology, and management".)

Other causes of respiratory insufficiency in the PACU are upper airway obstruction, lower airway or pulmonary complications, or hypoventilation due to a depressed level of consciousness or neuromuscular weakness. These problems are discussed separately. (See "Respiratory problems in the post-anesthesia care unit (PACU)".)

CARDIOVASCULAR COMPLICATIONS — Cardiovascular problems in the post-anesthesia care unit (PACU) include hypotension, hypertension, cardiac arrhythmias, myocardial ischemia, and decompensated heart failure. These problems are discussed separately. (See "Cardiovascular problems in the post-anesthesia care unit (PACU)".)

NEUROPSYCHIATRIC COMPLICATIONS

Intraoperative awareness with recall — Awareness with recall following general anesthesia refers to intraoperative consciousness with postoperative recall of events. Patients are queried regarding possible awareness in the post-anesthesia care unit (PACU) and/or on the first postoperative day. Further evaluation is performed if awareness is suspected, and psychological support is offered and arranged. Prevention is discussed separately. (See "Accidental awareness during general anesthesia".)

Delayed emergence and emergence delirium — Failure to return to a fully conscious state in a timely fashion following administration of general anesthesia may manifest as delayed emergence or emergence delirium. These conditions are typically temporary and gradually resolve over 30 to 60 minutes. In rare cases, the cause is a serious neurologic or medical condition requiring urgent intervention. Management of delayed emergence and delirium in the PACU is addressed separately. (See "Delayed emergence and emergence delirium in adults".)

Visual disturbance — Corneal abrasion is the most common cause of eye pain with or without visual disturbance in the postoperative period. Typically, the patient complains of the sensation of a foreign body in the affected eye. Causes, diagnosis and management of corneal abrasion are discussed separately. (See "Postoperative visual loss after anesthesia for nonocular surgery", section on 'Corneal abrasion'.)

Although rare, a patient may awaken from anesthesia with partial or complete loss of vision (with or without pain), prompting the need for urgent ophthalmologic consultation. Causes that require immediate treatment include ischemic optic neuropathy, cerebral visual loss, or retinal artery occlusion, as well as less common causes such as acute angle-closure glaucoma, retrobulbar hematoma, or pituitary apoplexy. Causes, diagnosis and management of postoperative vision loss are discussed separately. (See "Postoperative visual loss after anesthesia for nonocular surgery".)

Spinal epidural hematoma — Spinal epidural hematoma (SEH) is an extremely rare complication of neuraxial anesthesia. Patients who have received medications affecting hemostasis (eg, anticoagulant or antiplatelet agents), particularly those having vascular surgery, are at highest risk [5-7] (see "Neuraxial anesthesia/analgesia techniques in the patient receiving anticoagulant or antiplatelet medication", section on 'Spinal epidural hematoma (SEH)'). Risk is very low in obstetric patients.

Since epidural catheters are often placed just prior to induction of anesthesia, presence of an epidural hematoma may not become apparent until the effects of anesthetics and sedatives have worn off. The most common presenting symptoms for neurologically significant SEH are progressive motor block, sensory block, or bowel and bladder dysfunction; back pain is a less common presenting complaint [6,8].

Lack of expected resolution of motor block may raise concern for SEH. Although rare, SEH is a medical emergency that requires urgent assessment and treatment. Typically, emergency magnetic resonance imaging (MRI) is performed (or computed tomography [CT] scan if MRI is contraindicated). If SEH is detected, urgent consultation with the neurosurgery or orthopedic spine surgery service is necessary for possible decompressive laminectomy since neurologic recovery is more likely if decompression occurs within eight hours of symptom onset. (See "Neuraxial anesthesia/analgesia techniques in the patient receiving anticoagulant or antiplatelet medication", section on 'Prevention of neurologic damage from spinal hematoma'.)

HYPOTHERMIA OR HYPERTHERMIA — Postoperative temperature derangements are common; thus, temperature is measured during initial assessment upon arrival in the post-anesthesia care unit (PACU). Both hypothermia and hyperthermia have negative consequences in the immediate postoperative period, and either may cause shivering and/or thermal discomfort. These problems are promptly treated, as discussed separately. (See "Perioperative temperature management", section on 'Postoperative temperature derangements'.)

INABILITY TO VOID — Postoperative urinary retention (POUR) is common following anesthesia. The incidence varies widely, ranging from 5 to 70 percent [9]. In the absence of urologic pathology, postoperative inability to void is usually transient, but may be prolonged in some patients. (See "Postoperative urinary retention in females" and "Complications of inguinal and femoral hernia repair", section on 'Urinary retention'.)

Risk factors — Risk factors for POUR are patient-specific, procedure-specific, and anesthetic-specific.

●Patient factors – Older age, male sex, history of preexisting urinary retention, neurologic disease (eg, cerebral palsy, neuropathy, multiple sclerosis), or prior pelvic surgery.

●Procedural factors – Anorectal surgery, joint arthroplasty, hernia repair, or incontinence surgery.

●Anesthetic factors – Excessive fluid administration, selected medications (eg, opioids, anticholinergic agents, beta-blockers, sympathomimetics), prolonged duration of anesthesia, and type of anesthesia (with neuraxial anesthesia being more likely to cause POUR compared with general anesthesia).

Evaluation and treatment — Patients who are unable to void in the post-anesthesia care unit (PACU) may or may not complain of bladder fullness or lower abdominal discomfort, and physical examination is not sufficiently sensitive to detect bladder volume before the development of overdistention [10]. Thus, bladder volume is measured directly either with ultrasound or by draining the bladder, which requires catheterization. We prefer bladder ultrasound because this noninvasive technique will usually confirm the diagnosis. This technique is employed in any patient with risk factors for POUR who remains unable to void four hours after surgery [11,12]. If >600 mL is measured on ultrasound, or if the patient has discomfort with suspected inaccuracy of the ultrasound measurement (eg, due to body habitus, tissue edema, prior surgery with scarring), a one-time bladder catheterization is performed while the patient is still in the PACU. The volume of urine drained in the first 10 to 15 minutes after bladder catheterization should be noted and recorded. If volume exceeds 400 mL in a patient who will be admitted as a hospital inpatient, the catheter may be left in place. Clean intermittent catheterization is also an option [13]. (See "Acute urinary retention", section on 'Bladder decompression'.)

In some cases, ambulatory patients who have no risk factors for POUR and <600 mL of urine measured with bladder ultrasound may be discharged home without being catheterized even if they have not urinated [9]. All patients who were unable to spontaneously void prior to discharge (whether they were catheterized or not) are instructed to seek medical assistance if they are still unable to void eight hours after discharge. (See "Acute urinary retention", section on 'Subsequent evaluation and management' and "Postoperative urinary retention in females", section on 'Management'.)

DISCHARGE FROM THE POST-ANESTHESIA CARE UNIT

Standard discharge criteria — Discharge criteria are designed to determine a patient's readiness to safely leave the post-anesthesia care unit (PACU). Several scoring systems have been developed, both for the Phase I and Phase II PACU periods [14-17] (see 'Phases in the post-anesthesia care unit' above). For example, the Postanesthetic Discharge Scoring System (PADSS) is based on vital signs, activity level, nausea or vomiting, pain, surgical bleeding, and intake and output; criteria for discharge to home typically include a PADSS score ≥9 [17]. A commonly used modification of the PADSS system is shown in the table (table 4). Another example is the Aldrete score, which includes five elements (activity, respiration, circulation, consciousness, oxygen saturation) [16]. The Modified Aldrete system includes five additional elements that are particularly useful during the Phase II recovery period prior to discharge to home (dressing, pain, ambulation, feeding, urine output) [15].

Additional considerations may be applicable for some inpatients. The author uses the following criteria prior to discharge to a hospital ward:

●Patent airway

●Adequate and stable respiratory function

●Stable vital signs, typically within 20 percent of baseline values

●Adequate perfusion

●Appropriate or baseline responsiveness

●Appropriate or baseline orientation to person, time and place in a responsive patient

●Temperature ≥36°C and acceptable comfort level without symptoms of hypothermia or shivering

●Adequate pain control assessed by patient, nurse and anesthesiologist

●Patent intravenous vascular access

●Absence of bladder distention

●Adequate urine output, if applicable

●Intact and patent tubes, drains, and other catheters

●Absence of unexpected volumes of bleeding or wound drainage

●Intact dressing(s) at the procedural site(s)

For a patient who received a neuraxial (spinal or epidural) anesthetic, the patient should meet these additional criteria:

●Ability to wiggle toes or raise hips, as expected considering baseline status

●Stable blood pressure when head of bed elevated 30 degrees

●Completed current orders for continuous epidural infusions or patient-controlled epidural analgesia (PCEA)

In some cases, a patient may be discharged from the PACU when one or more of these criteria are unmet if there is consensus among the surgeon (or proceduralist), anesthesiologist, and PACU nurse. Ideally, each patient should be assessed by an anesthesiologist prior to discharge, with documentation of any exceptions to standard discharge criteria. Fully trained nurses should be available to care for all postoperative patients until the time of discharge [14].

In some cases, length of stay in the PACU may be delayed due to administrative issues (eg, lack of availability of hospital ward beds or clinician anesthesiologist for official discharge from PACU, rather than clinical reasons) [18].

Fast-track discharge criteria — A "fast track" pathway for discharge from the PACU is appropriate for some ambulatory surgical patients [19-21]. Patients who are "fast-tracked" bypass Phase I recovery and proceed directly from the operating room to Phase II recovery. The main benefits of this approach are shorter times to patient discharge and increased PACU productivity. Most fast-track protocols involve the use of preemptive analgesia and intraoperative use of short-acting anesthetic drugs and techniques. Careful patient selection is needed to ensure that a fast-track pathway does not increase risk of postoperative morbidity.

POST-ANESTHETIC EVALUATION — The Centers for Medicare & Medicaid Services (CMS) require that a post-anesthetic evaluation be completed and documented by a qualified anesthesia provider (eg, an anesthesiologist or a certified registered nurse anesthetist or anesthesiology assistant operating under the supervision of an anesthesiologist) no more than 48 hours after all surgeries or procedures requiring anesthesia [22]. The provider who performs the post-anesthetic evaluation need not be the same individual who performed the anesthetic.

Required elements of the post-anesthetic evaluation include the following:

●Respiratory function, including respiratory rate (RR), peripheral oxygen saturation (SpO₂), and airway patency

●Cardiovascular function, including heart rate (HR) and blood pressure (BP)

●Mental status, including responsiveness and orientation

●Temperature

●Pain level

●Presence of nausea and/or vomiting

●Adequate postoperative hydration

●Assessment for recall of intraoperative events

The post-anesthetic evaluation should be performed when the patient is awake enough to participate in the interview. If the patient cannot participate within the 48-hour time frame, the anesthesia provider documents the reason (eg, sedation with controlled ventilation).

For patients having same-day surgery, the post-anesthetic evaluation may be completed by means of a telephone interview, as allowed by state laws and hospital policies [23].

RESOURCES AND GUIDELINES

American Society of Anesthesiologists (ASA) — The American Society of Anesthesiologists (ASA), Association of Anesthetists of Great Britain and Ireland, and government regulatory agencies in the United States have published and updated practice guidelines and standards for post-anesthesia care [1,24-26].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Postoperative nausea and vomiting".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Nausea and vomiting after surgery (The Basics)")

SUMMARY AND RECOMMENDATIONS

●PACU admission procedures

•Standardized handoff – The initial handoff in the post-anesthesia care unit (PACU) from the anesthesiologist and other intraoperative personnel (eg, circulating nurse and surgeon) is standardized (table 1). (See 'Initial handoff' above.)

•Initial assessment and care – Airway patency, respiratory rate (RR), peripheral oxygen saturation (SpO₂), heart rate (HR), blood pressure (BP), the electrocardiogram (ECG), mental status, neuromuscular function, temperature, pain, and nausea or vomiting are assessed upon arrival in the PACU. After initial assessment, RR, SpO₂, HR, and the ECG are monitored continuously, while the other parameters are assessed frequently. A record is maintained to document these assessments and medications administered during the PACU stay. (See 'Assessment, monitoring, and care' above.)

•Assessment of neuraxial block – In patients who have received a neuraxial block, the degree of analgesic efficacy and gradual return of motor and sensory function are documented. Suspected complications of a neuraxial anesthetic, in particular spinal epidural hematoma (SEH), may require urgent assessment and treatment. (See 'Assessment after neuraxial block' above and 'Spinal epidural hematoma' above.)

●Potential complications – One or more postoperative problems occurs in nearly 25 percent of patients in the PACU. These include (see 'Incidence of complications' above):

•Postoperative nausea and/or vomiting (PONV) – PONV is the most common problem. (See 'Postoperative nausea and vomiting' above.)

•Respiratory and cardiovascular complications – (See 'Respiratory complications' above and 'Cardiovascular complications' above.)

•Neuropsychiatric problems – Delayed emergence, emergence delirium, visual disturbances, SEH, and intraoperative awareness with recall of intraoperative events may occur. (See 'Neuropsychiatric complications' above.)

•Temperature derangements – Both hypothermia or hyperthermia have negative consequences in the immediate postoperative period and either may cause shivering and/or thermal discomfort. These problems are promptly treated. (See 'Hypothermia or hyperthermia' above.)

•Inability to void – Patients with patient-specific, procedure-specific, and/or anesthetic-specific risk factors for urinary retention should undergo assessment of urinary volume with bladder ultrasound to determine if one-time catheterization is needed prior to PACU discharge. Patients are instructed to seek medical attention if they have not spontaneously voided within eight hours after discharge. (See 'Inability to void' above.)

●Discharge criteria – Standardized discharge criteria are designed to determine a patient's readiness to safely leave the PACU setting. An example is the Postanesthetic Discharge Scoring System (PADSS), with points based on vital signs, activity level, nausea and/or vomiting, pain, and surgical bleeding (table 4). (See 'Discharge from the post-anesthesia care unit' above.)

●Post-anesthetic evaluation – An evaluation should be completed and documented by a qualified anesthesia provider (eg, an anesthesiologist or certified registered nurse anesthetist or anesthesiology assistant) within 48 hours of the procedure. Respiratory and cardiovascular function, mental status, temperature, pain level, nausea or vomiting, hydration status, and possible awareness with recall are assessed. (See 'Post-anesthetic evaluation' above.)