The effects of CO sub(2)-insufflation with 5 and 10 mmHg during thoracoscopy on cerebral oxygenation and hemodynamics in piglets: an animal experimental study

Objective: To evaluate the effect of CO sub(2)-insufflation with 5 and 10 mmHg on cerebral oxygenation and hemodynamics in neonates. Background: An increasing percentage of surgical interventions in neonates are performed by minimal invasive techniques. Recently, concerns have been raised regarding a decrease of cerebral oxygenation in neonates during thoracoscopy as a result of CO sub(2)-insufflation. Methods: This was an animal experimental study. Piglets were anesthetized, intubated, ventilated, and surgically prepared for CO sub(2)-insufflation. Insufflation was done with 5 or 10 mmHg CO sub(2) during 1 h. Arterial saturation (SaO sub(2)), heart rate (HR), mean arterial blood pressure (MABP), and cerebral oxygenation (rScO sub(2)) were monitored. CFTOE, an estimator of cerebral oxygen extraction ((SaO sub(2) - rScO sub(2))/SaO sub(2))), was calculated. Arterial blood gases were drawn every 15': pre (T0), during (T1-T4) and after CO sub(2)-insufflation (T5). Results: Ten piglets (4 kg) were randomized for 5 (P5) and 10 (P10) mmHg CO sub(2)-insufflation. Two P10 piglets needed resuscitation after insufflation, none P5. Linear mixed-effect modeling of paCO sub(2), pH, and SaO sub(2) showed that values were dependent on time and time squared (p < 0.001) but were not different between the 5 and 10 mmHg groups. Analysis demonstrated significant changes over time in heart rate and MABP between the 5 and 10 mmHg groups, with a significant higher heart rate and lower blood pressure in the 10 mmHg group (p < 0.001). For rScO sub(2) and cFTOE, no group differences could be demonstrated, but a significant effect of time was found: rScO sub(2) increased and cFTOE decreased (p < 0.001). Conclusions: Insufflation of CO sub(2) during thoracoscopy with 10 mmHg caused more severe hemodynamic instability and seems to be related with a decrease of cerebral perfusion as represented by a higher oxygen extraction. CO sub(2)-insufflation of 5 mmHg for thoracoscopy seems to have no adverse effects on cerebral oxygenation.