Assessment of respiratory function

Question 1

History

Answer 1

• Significant risk factors for post-operative pulmonary complications should be identified (see E p. 85).
• Details of hospital admissions with respiratory disease should be noted, particularly if the patient was admitted to intensivecare.
• If the patient has chronic lung disease, compare the current respiratory function with previous disease trends.
• Explore symptoms such as cough and sputum production. Send a sputum specimen for culture and sensitivity.
• note past and present cigarette consumption.
• Review current treatment, reversibility of symptoms with bronchodilators, and steroid intake.
• there is no evidence that screening for sleep apnoea affects surgical complication rates, but it is advisable to question obese patients about symptoms suggestive of OSA prior to major surgery (see E p. 112).
• Any history suggesting unrecognized chronic lung disease or heart failure, such as exercise intolerance, unexplained dyspnoea, or cough, requires further consideration.
• Dyspnoea can be described using Roizen’s classification. Undiagnosed dyspnoea of grade II or worse may require further investigation (Box5.1).

Question 2

Roizen’s classification ofdyspnoea

Answer 2

grade 0: : no dyspnoea while walking on the level at normal pace ‘

Grade I: ‘I am able to walk as far as Ilike, provided Itake my time’

grade II: Specific street block limitation—‘I have to stop for a while after one or two blocks’

grade III: Dyspnoea on mild exertion—‘I have to stop and rest, going from the kitchen to the bathroom’

grade IV : Dyspnoea at rest

Question 3

Examination

Answer 3

• Abnormal findings on clinical examination are predictive of pulmonary complications after abdominal surgery.
• Physical examination should be directed toward evidence for obstructive lung disease. Signs, such as decreased breath sounds, wheeze, or prolonged expiratory phase, are important.
• Measurement of O2 saturation by oximetry helps to stratify risk and is useful before high-risk surgery.
• Aformal assessment of exercise tolerance, such as stair climbing or the 6-minute walk test (6MWt), correlates well with PFts and provides a reliable test of pulmonary function. However, it also reflects the CVS status, cooperation, and determination and is an impractical assessment for those with limited mobility

Question 4

Investigations

Answer 4

• All candidates for lung resection should have preoperative PFts performed.
• For all other procedures, laboratory tests serve as adjuncts to the clinical evaluation and should be obtained only in selected patients.