Laparoscopy

Procedure

CO2 Absorption and Excretion During Laparoscopy

  • CO2 Absorption from Peritoneal Space: CO2 is rapidly absorbed from the peritoneal space during laparoscopy -> this may result in respiratory acidosis, if not properly managed
    • Direct effects of hypercapnia + acidosis: decreased mycocardial contractility, snesitization of myocardium to arrhythmogenic effects of pressors, systemic vasodilation
    • Centrally-mediated (autonomic) effects of hypercapnia: sympathetic stimulation with tachycardia and vasoconstriction
  • Factors Increasing CO2 Absorption During Laparoscopy
    • High intra-abdominal pressure
    • Prolonged laparoscopic surgery: allows more time to absorb CO2
  • Factors Decreasing CO2 Excretion During Laparoscopy
    • Anesthesiology mismanagement with inadequate minute ventilation maintained on the ventilator
    • Lung disease: this will increase the required minute ventilation to maintain normal pCO2 during the case
    • High intra-abdominal pressure: cephalad displacement of the diaphragm decreases lung volumes and produces restriction -> impairs mechanical ventilation
    • Trendelenburg position: cephalad displacement of the diaphragm decreases lung volumes and produces restriction -> impairs mechanical ventilation

Effects of Increased Intra-Abdominal Pressure During Laparoscopy

  • Mechanical Impairment of Venous Return: decreased preload
  • Enhanced CO2 Absorption: as noted above
  • Impairment of CO2 Excretion via Minute Ventilation: as noted above

  • Monitoring of intra-abdominal pressure during laparoscopy is crucial, since it may contribute to both increased CO2 absorption and decreased CO2 excretion (via ventilation)

  • Maintenance of low-moderate intra-abdominal pressures (<12 mm Hg) during laparoscopy can decrease the incidence of adverse effects that result from abdominal CO2 insufflation

Adverse Effects/Complications

  • Capnothorax (see Capnothorax, [[Capnothorax]])
  • CO2 Pneumoperitoneum (see Pneumoperitoneum, [[Pneumoperitoneum]])
  • Decreased Splanchnic Perfusion: proportional to the elevation in intra-abdominal pressure
  • Intra-Operative Hypercapnia (see Hypercapnia, [[Hypercapnia]])

References

  • Circulatory and Respiratory Complications of Carbon Dioxide Insufflation. Dig Surg 2004;21:95–105