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RESPIRATORY

ASSESSMENT

Data Gathering

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History

  • Chronic lung disease: previous work-up (PFTs, radiography, ABG), previous prednisone use, frequency of MDI/HHN use, prior hospitalizations/intubation, use of O2

  • OSA: last sleep study, settings of PAP

  • Difficult intubation: need anesthesia records

  • Previous perioperative respiratory problems

Symptoms

  • Cough

  • Dyspnea

  • Hemoptysis

  • Chest pain

  • Wheezing

Exam

  • Abnormal breath sounds

  • Clubbing

  • Hypoxemia

  • Airway features (see below)

Risk Stratification

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Diagnostic Studies

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  • Chest radiography indications (Choosing Wisely):

    • Signs or symptoms of active pulmonary disease​

  • Pulmonary function testing indications:

    • Pulmonary resection

    • As indicated in non-perioperative setting for undiagnosed/uncharacterized respiratory disease​

  • Arterial blood gas indications:

    • As indicated in non-perioperative setting​ for suspected gas exchange or acid-base disorder

  • Serum bicarbonate indications:

    • High risk for OSA (STOP-Bang ​≥5) (Chung et al)

General Pulmonary Risk Index (ARISCAT Index)

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OSA Risk Index (if not already diagnosed with OSA)

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Other Risk Factors for PPCs

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  • Chronic lung disease

  • Functional dependence (requiring assistance with ADLs)

  • CHF (NYHA class ≥II)

  • Abnormal lung exam findings

  • Recent respiratory symptoms

  • Smoking

  • ASA class >3

  • General anesthesia

  • Cirrhosis

Difficult Airway Risk Factors

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Predictors of Difficult Intubation

TEST

Upper lip bite test class 3

Wilson score ≥2

Hyomental distance <3 cm

Mallampati class III-IV

Interincisor gap <2 cm

Decreased neck range of motion

Thyromental distance <4 cm

SENSITIVITY

60%

43%

20%

55%

36%

28%

45%

SPECIFICTY

96%

95%

97%

87%

90%

93%

86%

Predictors of Difficult Mask Ventilation

DIFFMASK.jpg

MANAGEMENT

Indications for Surgical Delay

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  • STOP-BANG ≥5 plus uncontrolled systemic disease or impaired ventilation/gas exchange (eg, hypoventilation syndrome, severe pulmonary hypertension, hypoxia without CV cause) [Chung et al]

  • New or worsened respiratory symptoms [strong predictor of respiratory failure in Canet et al]

  • Recent respiratory infection within past 30 days [strong predictor of all PPCs in Mazo et al]

General Risk Reduction Measures

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All of the risk reduction methods below are supported by evidence, but no guidelines or studies provide direction on which to use based on risk stratification. The protocol below is the author's approach and has not been externally validated.​

  • LOW risk of PPCs:

    • Optimize chronic lung disease (eg, add controller meds if using albterol >3 times/week)

    • If smoking, counsel & provide resources for cessation

    • Early mobilization

  • INTERMEDIATE risk of PPCs: all of above +

    • Incentive spirometry (IS)

    • Consider use of regional/neuraxial anesthesia/analgesia & lung-protective ventilation if receiving general anesthesia

  • HIGH risk of PPCs: all of above​ +

    • Preoperative lung expansion (deep breathing exercises, IS for 1-2 weeks before surgery)​

    • Postoperative intermittent positive pressure breathing (IPPB)

    • Consider extubation to positive airway pressure ventilation if receiving general anesthesia

    • Consider increased level of postoperative triage (admission instead of discharge, ICU instead of floor) & avoidance of ambulatory surgical center for operative location

    • Consider continuous pulse oximetry or capnography if receiving opioids

OSA Risk Reduction Measures [Chung et al, ASA OSA Task Force]

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  • Sleep medicine evaluation for patients at high risk for undiagnosed OSA (STOP-Bang ≥5) plus uncontrolled systemic disease (eg, pulmonary hypertension) or impaired gas exchange (ie, hypoxemia or elevated serum bicarbonate)

  • Consider increased level of postoperative triage (admission instead of discharge, ICU instead of floor) & avoidance of ambulatory surgical center for operative location

  • Consider use of regional anesthesia/analgesia

  • Minimize use of sedatives and opioids as much as possible

  • If prescribed PAP therapy prior to surgery, bring equipment to hospital & continue use perioperatively

  • Utilize non-opioid analgesics as much as possible

  • Non-supine positioning (head of bed at 30 degrees) as allowed by surgical restrictions

  • Continuous pulse oximetry or capnography with continuous monitoring

  • Empiric trial of PAP therapy for patients with severe obstruction, hypoxemia or hypercapnia

Difficult Airway Risk Reduction

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Provide advance notification of anesthesiology for determination of appropriate planning

COUNSELING & COMMUNICATION

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  • Collaborate with patients' pulmonologists.

  • For patients particularly concerned about the risk of respiratory failure (requiring re-intubation or mechanical ventilation beyond 48 hours after surgery), provision of specific risk estimate of this risk may be useful. This can be calculated from the Gupta Respiratory Risk Index.

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