Pulmonary Physiologic Assessment of Operative Risk

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Pulmonary Physiologic Assessment of Operative Risk
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UPPER ABDOMINAL SURGERY

• Postoperative pulmonary collapse is related to
  diaphragm dysfunction, which is manifest in 50 to
  60 reduction in vital capacity for few hours to
  5 days.
• Preoperative PFT( pulmonary function test )with
  spirometry is unproven to predict increased
  postoperative pulmonary risk.

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LUNG RESECTION SURGERY

• If no lung is resected, the vital capacity
  declines 25 in early postoperative period and
  normalizes 4 to 6 weeks.
• When normal lung tissue is resected, the first is
  reduction of the pulmonary capillary bed. If
  pulmonary dysfunction exists, pulmonary
  hypertension will lead to cor pulmonale and
  death.

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LUNG RESECTION SURGERY

• The 2nd effect of lung resection is reduction of
  ventilatory capacity.
• Inoperability means inability of tolerance after
  loss of functional lung tissue.
• The mortality of pneumonectomy is less than 5.

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Routine Pulmonary Function Studies
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Routine Pulmonary Function Studies

• Ferguson et al reported DLCO( diffusing capacity
  of lung for CO ) was the best predictor of
  postoperative pulmonary complications.
• DLCO measures the volume of diluted CO taken up
  by lung during a single breath held for 10
  seconds.

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Split Lung Function Studies

• Unilateral ventilation is measured by inhalation
  Xe133 and perfusion is measured by IV Tc99m
  albumin macroaggregates.

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Split Lung Function Studies

• Postoperative FEV1 preoperative
  FEV1-preoperative FEV1 x of function of
  tumor-containing lung X( no. of segments of
  resected lobe/ total no. of segments of the lung
  )
• E.g. preoperative FEV1 2.0L
• right lung function40
• RUL lobectomy will be done.
• Postoperative FEV1 2.0-2.0x40x3/101.76L

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Postoperative FEV1

• If radiospirometry is not done, then
• Postoperative FEV1 preoperative
  FEV1-preoperative FEV1 x 1/19x no. of resected
  segments
• E.g. preoperative FEV1 2.0L
• RUL lobectomy will be done.
• Postoperative FEV1 2.0-2.0x1/19x31.684

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Hemodynamic Studies

• TUPAO( temporary unilateral pulmonary artery
  occlusion ) inflation of the 50-ml balloon in
  the main PA to induce a physiologic pneumonectomy
• A PVR (pulmonary vascular resistance) is more
  than 190 dyne-sec-cm-5 than postoperative
  mortality is predicted.

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Exercise Test

• Maximum oxygen consumption (VO2max) is measured.

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SUMMARY

• The PFT appears to play a minor role in upper
  abdominal surgery and open heart surgery.
• No patient should be rejected for curative
  surgery for lung cancer based solely on
  spirometric finding.