[Detection of microbubbles formed in the blood/CO2 interphase during decompression in barometric conditions similar to laparoscopy].
OBJECTIVE
Intraperitoneal insufflation (IPI) with CO2 during laparoscopic surgery establishes a pressure gradient that determines the passage of gas from the peritoneal cavity to the blood and surrounding tissues. The transport and clearance of CO2 are assured by proper sweeping when regional blood flow is adequate in volume and distribution. But if IPI hyperpressure surpasses regional venous capillary pressure (10 to 15 mmHg) and there is no cardio-circulatory adaptation to the phenomenon, CO2 clearance may be compromised. Under these conditions, the expected post-insufflation increase in PetCO2 will not take place. Bearing in mind the physical characteristics of CO2, retention of this gas in the intraperitoneal cavity produces blood and tissue saturation under a higher-than-atmospheric pressure, after a certain period of time in contact. Rapid intraperitoneal decompression after laparoscopic surgery carries with it the risk of microbubble formation due to release of CO2 that had been dissolved under hyperbaric conditions.


METHODS
To test this hypothesis, the barometric conditions of laparoscopy were reproduced inside an observation capsule containing blood and CO2.


RESULTS
Magnification revealed that after decompression bubbles formed in the blood/CO2 interphase. The images were recorded on magnetic videotape. Thirty minutes after decompression, the bubbles could still be seen, even after the interphase was swept with a current of air.


CONCLUSIONS
Rapid intraperitoneal decompression after laparoscopy can generate the formation of microbubbles which, if not eliminated, will give rise to local ischemic manifestations. This same decompression, correcting the local circulatory alterations and activating the CO2 transport that had been compromised, could introduce gas bubbles into the blood stream such as are responsible for delayed gaseous microembolism. The simultaneous observation of changes in PetCO2 (stability or post-insufflation decreases) and hemodynamic parameters during laparoscopy, would allow evolving anomalies to be detected early and therapeutic action to be taken to prevent the formation of microbubbles.
Muchada
R
R
Departamento de Anestesia-Reanimación, Clínica Mutualista E. André, INSERM Unidad 281, Lyon, Francia.
Rinaldi
A
A
Stern
P
P
D002245:Carbon Dioxide / Q000097:blood* / Q000378:metabolism; D007327:Insufflation; D010535:Laparoscopy; D013499:Surface Properties
D002245:Carbon Dioxide