When we perform a laparoscopy, we put in a needle first to introduce carbon dioxide there. When the needle is inside, we attach a needle to it and aspirate.
"If we get urine, we are in a full bladder. If we get stools, we are in the bowel. If we get blood, God forbid, we are in a blood vessel" I teach the resident doctors. "Now aspirate and see."
The one performing the operation aspirates into a syringe containing normal saline. Air bubbles enter the syringe from its distal end.
"Where did that air come from?" I ask. I know I cannot keep a straight face, but the mask worn in the OT helps. They think about it. Some of them keep quiet. Some of them smile in answer. Some of them do not answer that question even the next time they are performing a laparoscopy and I am assisting them. A few of them give an interesting answer - "Normally there is some air in the peritoneal cavity."
I have not told them the answer yet. They all have forgotten that the peritoneal cavity is a potential cavity that contains just a film of fluid. There is no air or any gas there. The air enters the syringe because the syringe does not fit the needle very well and permits entry of air. I will continue to ask this question when I assist them perform laparoscopy. Makes them think. If they answer, either they are good, or they have read my post. I won't know which one, but both the possibilities would make me happy.
"If we get urine, we are in a full bladder. If we get stools, we are in the bowel. If we get blood, God forbid, we are in a blood vessel" I teach the resident doctors. "Now aspirate and see."
The one performing the operation aspirates into a syringe containing normal saline. Air bubbles enter the syringe from its distal end.
"Where did that air come from?" I ask. I know I cannot keep a straight face, but the mask worn in the OT helps. They think about it. Some of them keep quiet. Some of them smile in answer. Some of them do not answer that question even the next time they are performing a laparoscopy and I am assisting them. A few of them give an interesting answer - "Normally there is some air in the peritoneal cavity."
I have not told them the answer yet. They all have forgotten that the peritoneal cavity is a potential cavity that contains just a film of fluid. There is no air or any gas there. The air enters the syringe because the syringe does not fit the needle very well and permits entry of air. I will continue to ask this question when I assist them perform laparoscopy. Makes them think. If they answer, either they are good, or they have read my post. I won't know which one, but both the possibilities would make me happy.
