obstructive sleep apnea

Obstructive sleep apnea(OSA) is a syndrome characterized by periodic, partial, or complete obstruction of the upper airway during sleep.

This, in turn, causes repetitive arousal from sleep to restore airway patency,

which may result in daytime hypersomnolence or other daytime manifestations of disrupted sleep such as aggressive or distractible behavior in children. The airway obstruction may also cause episodic sleep-associated oxygen desaturation, episodic hypercarbia, and cardiovascular dysfunction.
A.  Table 1. Identification and Assessment of OSA: Example

1. Predisposing physical characteristics

a. BMI 35 kg/m2 [95th percentile for age and gender]*

b. Neck circumference 17 inches (men) or 16 inches (women)

c. Craniofacial abnormalities affecting the airway

d. Anatomical nasal obstruction

e. Tonsils nearly touching or touching in the midline

2. History of apparent airway obstruction during sleep (two or more of

the following are present; if patient lives alone or sleep is not observed

by another person, then only one of the following needs to be present)

a. Snoring (loud enough to be heard through closed door)

b. Frequent snoring

c. Observed pauses in breathing during sleep

d. Awakens from sleep with choking sensation

e. Frequent arousals from sleep

f. [Intermittent vocalization during sleep]*

g. [Parental report of restless sleep, difficulty breathing, or struggling

respiratory efforts during sleep]*

3. Somnolence (one or more of the following is present)

a. Frequent somnolence or fatigue despite adequate “sleep”

b. Falls asleep easily in a nonstimulating environment (

TV, reading, riding in or driving a car) despite adequate “sleep”

c. [Parent or teacher comments that child appears sleepy during the

day, is easily distracted, is overly aggressive, or has difficulty

concentrating]*

d. [Child often difficult to arouse at usual awakening time]*

If a patient has signs or symptoms in two or more of the above categories,

there is a significant probability that he or she has OSA. The severity of

OSA may be determined by sleep study (see below). If a sleep study is

not available, such patients should be treated as though they have

moderate sleep apnea unless one or more of the signs or symptoms

above is severely abnormal (

circumference, respiratory pauses that are frightening to the observer,

patient regularly falls asleep within minutes after being left unstimulated),

in which case they should be treated as though they have severe sleep

apnea.

B. the perioperative anesthetic management of a patient. However,

because sleep laboratories differ in their criteria for detecting episodes

of apnea and hypopnea, the Task Force believes that the sleep

laboratory’s assessment (none, mild, moderate, or severe) should take

precedence over the actual AHI (the number of episodes of sleep disordered

breathing per hour). If the overall severity is not indicated, it

may be determined by using the table below:

Severity of OSA   Adult AHI     Pediatric AHI

None                         0–5                     0

Mild OSA                  6–20                  1–5

Moderate OSA         21–40                 6–10

Severe OSA             40                       1

AHI apnea-hypopnea index; BMI body mass index; OSA obstructive

Clinical signs and symptoms suggesting the possibility of OSAe.g., watchinge.g., markedly increased BMI or neckIf a sleep study has been done, the results should be used to determine Points

II. Preoperative Preparation

Preoperative preparation is intended to improve or optimize an OSA patient’s perioperative physical status and includes (1) preoperative continuous positive airway pressure (CPAP) or noninvasive positive-pressure ventilation (NIPPV) or bilevel positive airway pressure (BiPAP®; Respironics, Murrysville, PA), (2) preoperative use of mandibular advancement or oral appliances, (3)

preoperative medications, or (4) preoperative weight loss

Preoperative initiation of CPAP should be considered, particularly if OSA is severe. For

patients who do not respond adequately to CPAP, NIPPV should be considered. In addition, the preoperative use of mandibular advancement devices or oral appliances

and preoperative weight loss should be considered when feasible.

III. Intraoperative Management

Intraoperative concerns in patients at increased perioperative risk from OSA include (1) choice of anesthetic technique, (2) airway management, and (3) patient monitoring.

Recommendations.

airway collapse and sleep deprivation, patients at increased perioperative risk from OSA are especially susceptible to the respiratory depressant and airway effects of sedatives, opioids, and inhaled anesthetics; therefore, in selecting intraoperative medications, the potential for

postoperative respiratory compromise should be considered.

For superficial procedures, one should consider the use of local anesthesia or peripheral nerve blocks,

with or without moderate sedation. If moderate sedation is used, ventilation should be continuously monitored by capnography or another automated method if feasible because of the increased risk of undetected airway obstruction in these patients. One should consider administering CPAP or using an oral appliance during sedation to patients previously treated with these modalities. General

anesthesia with a secure airway is preferable to deep sedation without a secure airway, particularly for procedures that may mechanically compromise the airway.

Major conduction anesthesia (spinal/epidural) should be considered for peripheral procedures. Unless there is a medical or surgical contraindication, patients at increased perioperative risk from OSA should be extubated while awake. Full reversal of neuromuscular block should be verified before extubation. When possible, extubation and recovery should be carried out in the lateral, semiupright, or other nonsupine position.

Postoperative Management

Postoperative concerns in the management of patients

with OSA include (1) analgesia, (2) oxygenation, (3) patient positioning, and (4) monitoring. Risk factors for respiratory depression include the systemic and neuraxial administration of opioids, administration of sedatives, site and invasiveness of surgical procedure, and the underlying severity of the sleep apnea

Recommendations. Regional analgesic techniques

are used, continuous background infusions should be used with extreme caution or avoided entirely. Nonsteroidal antiinflammatory agents and other modalities ( should be considered if appropriate to reduce opioid requirements. Clinicians are cautioned that the concurrent administration of sedative agents (barbiturates) increases the risk of respiratory depression and airway obstruction.

Supplemental oxygen should be administered continuously to all patients who are at increased perioperative risk from OSA until they are able to maintain their baseline oxygen saturation while breathing room air. The

Task Force cautions that supplemental oxygen may increase

the duration of apneic episodes and may hinder

detection of atelectasis, transient apnea, and hypoventilation

by pulse oximetry. CPAP or NIPPV, with or without

supplemental oxygen, should be continuously ad-ministered when feasible ( not ambulating) to patients who were using these modalities preoperatively, unless contraindicated by the surgical procedure.

Factors to be considered in determining whether outpatient care is appropriate include (1) sleep apnea status, (2) anatomical and physiologic abnormalities, (3) status of coexisting diseases, (4) nature of surgery, (5) type of anesthesia, (6) need for postoperative opioids, (7) patient age, (8) adequacy of postdischarge observation, and (9) capabilities of the outpatient facility. The

availability of emergency difficult airway equipment, respiratory care equipment, radiology facilities, clinical laboratory facilities, and a transfer agreement with an inpatient facility should be considered in making this determination.

These patients should not be discharged from the recovery area to an unmonitored setting ( hospital bed) until they are no longer at risk for postoperative respiratory depression. Because of their propensity to develop airway obstruction or central respiratory depression, this may require a longer stay as compared with non-OSA patients undergoing similar procedures. Adequacy of postoperative respiratory function may be documented by observing patients in an unstimulated environment,

preferably while they seem to be asleep, to establish that they are able to maintain their baseline oxygen saturation while breathing room air.

summary:

1. Preoperative evaluation

a. Medical records review

b. Patient and family interview

c. Screening questionnaire

d. Focused physical examination

e. Sleep study

2. Preoperative preparation

a. Preoperative treatment/optimization for OSA (

NIPPV, mandibular appliances, medical treatment)

b. Consult the American Society of Anesthesiologists “Practice

Guidelines for Management of the Difficult Airway”

c. Limit procedures to facilities with full hospital services

3. Intraoperative management

a. Anesthetic technique

(i) Local or regional anesthesia

(ii) Combined regional and general anesthesia

anesthesia

(iii) Sedation

b. Monitoring

(i) Continuously monitor the respiratory depressant effects of

sedatives and/or opioids ( ventilation, oxygenation, automated apnea monitoring)

(ii) Special intraoperative monitoring techniques (arterial line,

pulmonary artery catheter)

c. Extubation

(i) Verify the full reversal of neuromuscular block before extubation

(ii) Extubate patients after they are fully awake ( partially awake)

(iii) Extubate patients in the semiupright, lateral, or prone positions

4. Postoperative management

a. Analgesic use

(i) Regional analgesic techniques without neuraxial opioids

should be considered to reduce or eliminate the requirement for systemic opioids in patients at increased perioperative risk from OSA. If neuraxial analgesia is planned, weigh the benefits (improved analgesia, decreased need for systemic opioids) and risks (respiratory depression from rostral spread) of using an opioid or opioid–local anesthetic mixture as compared with a local anesthetic alone. If patient-controlled systemic opioidse.g., ice, transcutaneous electrical nerve stimulation)e.g., benzodiazepines,e.g., when patients arei.e., home or unmonitorede.g., CPAP,versus general anesthesiaversus generalversus general anesthesiae.g., level of consciousness, pulmonaryvs. asleep orvs. supine)

versus

(ii) Neuraxial opioids

(iii) Oral analgesics

(iv) PCA without a background infusion

background infusion

(v) Titration or lower dosage levels of systemic opioids

b. Oxygenation

(i) Supplemental oxygen

(ii) CPAP

(iii) CPAP for patients who had previously been on CPAP

systemic opioidsversus systemic opioidsversus parenteral opioidsversus PCA with aversus no supplemental oxygenversus no CPAP (oxygen or room air)versus

CPAP for patients not previously on CPAP

(iv) NIPPV

c. Positioning patients in the lateral, prone, or tonsil position

versus no NIPPV (CPAP, oxygen, or room air)

versus

d. Monitoring

(i) Telemetry monitoring systems  systems

(ii) Monitored settings

e. Duration of stay

(i) Extended stay in PACU

(ii) Hospital admission the supine positionversus no telemetry monitoringversus routine hospital wardsversus no extended stay in PACUversus discharge home

Table 2. OSA Scoring System: Example

A. Severity of sleep apnea based on sleep study (or

clinical indicators if sleep study not available).

Point score _____ (0–3)*†

Severity of OSA (table 1)

None 0

Mild 1

Moderate 2

Severe 3

B. Invasiveness of surgery and anesthesia. Point score_____ (0–3)

Type of surgery and anesthesia

Superficial surgery under local or peripheral nerve block anesthesia without sedation 0

Superficial surgery with moderate sedation or general anesthesia 1

Peripheral surgery with spinal or epidural anesthesia (with no more than moderate sedation) 1

Peripheral surgery with general anesthesia 2

Airway surgery with moderate sedation 2

Major surgery, general anesthesia 3

Airway surgery, general anesthesia 3

C. Requirement for postoperative opioids. Point score_____ (0–3)

Opioid requirement

None 0

Low-dose oral opioids 1

High-dose oral opioids, parenteral or neuraxial opioids 3

D. Estimation of perioperative risk. Overall score the

score for A plus the greater of the score for either B or C. Point score _____ (0–6)‡

A scoring system similar to this table may be used to estimate whether a

patient is at increased perioperative risk of complications from obstructive

sleep apnea (OSA). This example, which has not been clinically validated, is

meant only as a guide, and clinical judgment should be used to assess the risk

of an individual patient.

* One point may be subtracted if a patient has been on continuous positive

airway pressure (CPAP) or noninvasive positive-pressure ventilation (NIPPV)

before surgery and will be using his or her appliance consistently during the

postoperative period. † One point should be added if a patient with mild or

moderate OSA also has a resting arterial carbon dioxide tension (PaCO2)

greater than 50 mmHg. ‡ Patients with score of 4 may be at increased

perioperative risk from OSA; patients with a score of 5 or 6 may be at

significantly increased perioperative risk from OSA.