A pause before connecting insufflation tubing to decrease the risk of air embolism

Air embolism is a rare but potentially fatal complication of laparoscopic surgery, especially among pediatric patients. A common theory as to why air embolism occurs during laparoscopy is that ambient air in the insufflation tubing can enter the vascular system when a trocar or Veress needle is inserted into a vessel or highly vascularized tissue. While some laparoscopic surgeons initiate CO₂ insufflation before attaching the tubing, there are no guidelines that recommend a delay after starting the flow of CO₂ and before connecting the insufflation tubing. We therefore assessed this "pause" at different flow rates and pressures.

We connected standard ten-foot laparoscopic insufflation tubing to a STORZ ENDOFLATOR® 50. We then attached the end of the tubing to a three-way stopcock connected to an end-tidal CO₂ monitor on an anesthesia machine. We turned on the insufflator at various flow rates and pressures and measured the time from initiation of insufflation to a visible increase on the end-tidal CO₂ monitor. We repeated each test at each insufflation setting 10 times.

The average time for CO₂ to reach the distal end of the insufflation tubing at clinically relevant settings for pediatric (or adult) laparoscopy ranged from 3.32 ± 0.27s (at 20 L/min, 20 mmHg) to 3.46 ± 0.10s (at 4 L/min, 6 mmHg). We found little variation in timing across clinically relevant flow rates and pressures, likely due to the slow increase in the insufflator flow rate.

We recommend waiting at least ten seconds, regardless of flow rate or pressure, between starting the flow of CO₂ and connecting the insufflation tubing to laparoscopic trocars or Veress needles. This pause will help ensure that there is no ambient air in the tubing during laparoscopy. Whereas CO₂ embolism may occur, air embolism should be a never event when using this guideline.