I’m confused about your statement that the suction control bottle has no purpose if it doesn’t bubble @2:10. If the suction is set at 15 cm water, the vent depth is at 20 cm, then the vacuum control bottle will not bubble but it is still applying suction. If it is still applying suction, then why would you say it has no purpose?
I have the same doubt. If we have a water valve of 2 cmH20, and a suction control set at a water valve of 20 cmH20 that is not bubbling, then an effective suction should range between 3 and 19 cmH20. Even if it's not over 20, it's still suction and making its job.
i have a question.. we are getting an exam about this but I don't actually understand why the pressure gets down when you put the suction on, can you help me with this ? Thank you a lot!
+Umoss Col Positive pressure and negative pressure are the same thing depending on which direction you choose to be positive, they both move air. When suction is applied to the chest tube system, you are applying negative pressure within the pleural space. If the suction control vent is not bubbling, the suction is less than 20 cm of water, once the suction control bubbles, applying more wall suction will only make the suction control bubble more, the suction control prevents more than 20 cm of suction (negative pressure) from being applied to the system. Hope this helps.
can you explain why when you increase the suction pressure it will only create more bubbles rather than exerting higher suction from the pleural cavity? Also, what will happen if you do not have that safety valve e.g. connecting that chamber straight to a suction?
+Psyche The safety vent does not allow the suction applied to the chest tube to exceed 20 cm of water because the vent is submerged in 20 cm of water. So when we connect to wall suction, the safety vent will begin to bubble when the wall suction exceeds 20 cm, the excessive suction is compensated by the entry of air into the safety vent, keeping the suction applied to the chest EXACTLY the amount the vent tube submerged in water, 20 cm. If not for the safety vent, then excess suction, suction that exceeds 20 cm, can do damage to the tissues in the chest. Hope this helps.
