Jax,
Thanks for posting this and for helping to increase the visibility of IPE.
As you noted, we're conducting a study on IPE and would welcome anyone who thinks they've experienced this to contact us. Our contact info is on our website, linked below.
I think that it's important to recognize that a number of factors can be at play when a diver or swimmer experiences pulmonary edema. On the surface, gravity tends to pull blood into the lower parts of the body. In the water,this effect is reduced or negated, and blood becomes more evenly distributed in the body. This results in a significant influx of blood into the lungs. If the pulmonary arteries are unable to dilate sufficiently to compensate for this, the resultant pulmonary hypertension can cause pulmonary edema, as you noted. In cold water, a swimmer or diver experiences peripheral vasoconstriction, which magnifies this effect by shunting blood away from the extremities and into the core.
Immersion plays a greater or lesser role depending on the individual's susceptibility. For example, in a superbly conditioned triathlete like Kat Calder-Becker, who we studied, the theory is that extremely high cardiac output combines with individual susceptibility to cause SIPE. On the other hand, a diver with underlying cardiac disease who's in equilibrium on the surface can suffer pulmonary edema on a dive if immersion, work level, temperature, and low cardiac output combine to overwhelm the pulmonary circulation. Immersion would certainly be a factor, but this would not be considered true immersion pulmonary edema.
At any rate, once pulmonary edema occurs, the treatment is essentially the same no matter what the cause. Qualified individuals should provide high-flow oxygen via mask and be prepared to support ventilations and circulation should the need arise. Sometimes, the positive pressure from assisted ventilation can be beneficial. This can be accomplished by using a CPR pocket mask or other barrier device. Some pocket masks have oxygen inlets and can be attached to an O2 bottle to increase the amount of oxygen the diver is receiving. As you noted, if a device like this isn't available, it can be beneficial for a qualified rescuer to don a nasal cannula and provide mouth-to-barrier ventilations. The American Heart Association encourages the use of CPR barriers but also notes that there has not been a reported incidence of disease transmission from direct mouth-to-mouth breathing. From personal experience, however, the presence of bodily fluids like vomit and mucus will make a rescuer very thankful for a barrier device.
CPAP devices and bag valve masks like the one pictured require specialized training and practical experience to be properly employed, and so should only be used by trained rescuers.
IPE and SIPE remain very rare, but prompt recognition will definitely increase a victim's chances of a positive outcome. Thanks again for posting this.
Best regards,
DDM
Thanks for posting this and for helping to increase the visibility of IPE.
As you noted, we're conducting a study on IPE and would welcome anyone who thinks they've experienced this to contact us. Our contact info is on our website, linked below.
I think that it's important to recognize that a number of factors can be at play when a diver or swimmer experiences pulmonary edema. On the surface, gravity tends to pull blood into the lower parts of the body. In the water,this effect is reduced or negated, and blood becomes more evenly distributed in the body. This results in a significant influx of blood into the lungs. If the pulmonary arteries are unable to dilate sufficiently to compensate for this, the resultant pulmonary hypertension can cause pulmonary edema, as you noted. In cold water, a swimmer or diver experiences peripheral vasoconstriction, which magnifies this effect by shunting blood away from the extremities and into the core.
Immersion plays a greater or lesser role depending on the individual's susceptibility. For example, in a superbly conditioned triathlete like Kat Calder-Becker, who we studied, the theory is that extremely high cardiac output combines with individual susceptibility to cause SIPE. On the other hand, a diver with underlying cardiac disease who's in equilibrium on the surface can suffer pulmonary edema on a dive if immersion, work level, temperature, and low cardiac output combine to overwhelm the pulmonary circulation. Immersion would certainly be a factor, but this would not be considered true immersion pulmonary edema.
At any rate, once pulmonary edema occurs, the treatment is essentially the same no matter what the cause. Qualified individuals should provide high-flow oxygen via mask and be prepared to support ventilations and circulation should the need arise. Sometimes, the positive pressure from assisted ventilation can be beneficial. This can be accomplished by using a CPR pocket mask or other barrier device. Some pocket masks have oxygen inlets and can be attached to an O2 bottle to increase the amount of oxygen the diver is receiving. As you noted, if a device like this isn't available, it can be beneficial for a qualified rescuer to don a nasal cannula and provide mouth-to-barrier ventilations. The American Heart Association encourages the use of CPR barriers but also notes that there has not been a reported incidence of disease transmission from direct mouth-to-mouth breathing. From personal experience, however, the presence of bodily fluids like vomit and mucus will make a rescuer very thankful for a barrier device.
CPAP devices and bag valve masks like the one pictured require specialized training and practical experience to be properly employed, and so should only be used by trained rescuers.
IPE and SIPE remain very rare, but prompt recognition will definitely increase a victim's chances of a positive outcome. Thanks again for posting this.
Best regards,
DDM
