Drowning: Pathophysiology and Risk Factors (Nursing)

00:01 Hi, I'm Doctor Rhonda Lawes and I want to welcome you to this video series on drowning. So let's get started.

00:08 And we're going to start with a definition.

00:10 So drowning is defined as the process of experiencing respiratory impairment from submersion or immersion in liquid.

00:19 Now I've got some scary statistics for you.

00:21 According to W.H.O., drowning causes over 230,000 deaths every year across the world.

00:28 It's the third leading cause of unintentional injury death globally.

00:33 Children under five and adolescents ages 15 to 19 have the highest drowning rates. Now, for every drowning death, it's estimated that 4 to 5 times as many have received emergency care for non-fatal submersion injuries.

00:46 So the term drowning can sometimes be confusing.

00:50 But for the sake of this discussion, drowning is the correct term, regardless of the outcome whether it's fatal, non-fatal with morbidity, or non-fatal without morbidity.

01:01 We're going to be using the term drowning.

01:03 You may have heard terms like near drowning or dry drowning or secondary drowning. These are no longer recommended in the literature.

01:12 Let's talk about the pathophysiology of drowning.

01:14 What actually happens when a client experiences this? Well, anyone's initial response to being submerged is to hold their breath.

01:22 Now, when they hold their breath as it continues, of course, carbon dioxide is going to build up in their bloodstream because they can't exhale carbon dioxide as if they were in air.

01:34 Now, what will happen eventually is they'll have this involuntary breathing reflex.

01:38 It's going to be eventually triggered because that rising CO2, which is going to cause them to aspirate water or take water into their lungs. Now, the aspiration will lead to Laryngospasm in about 10 to 15% of the cases. But in the majority of cases, Laryngospasm eventually subsides.

01:57 And that's what allows the water to enter the lungs.

02:00 Now, this is where it gets really bad.

02:02 When the water is in the lungs.

02:05 This causes the surfactant to wash out.

02:07 Remember, surfactant is meant to keep those alveoli open and round.

02:11 And so you can exchange CO2 and O2.

02:14 The water in the lungs causes that to be washed out and it doesn't work.

02:18 The alveoli will therefore collapse, which we call atelectasis.

02:23 So you end up with pulmonary edema that was not caused by the heart, otherwise known as non cardiogenic pulmonary edema.

02:31 You're going to have a ventilation perfusion mismatch.

02:34 It's going to lead to hypoxemia low oxygen in the blood and acidosis. The pH of their blood is going to become more acidic.

02:44 Now let's look at the pathophysiology of additional injury and drowning.

02:48 Hypoxic brain injury starts within 4 to 6 minutes of the patient being submerged.

02:53 The primary mechanism of injury and death is the hypoxemia, right. The lack of oxygen that leads to ischemic brain damage.

03:01 So that's the end of a very sad story.

03:04 We think about the brain injury that can start within 4 to 6 minutes.

03:08 And the primary problem is going to be ischemic brain damage due to lack of oxygen being delivered.

03:14 Now there are some other things that can also go wrong. There's something called secondary cascade. Now this means that the tissue could be injured during reperfusion. So the person's been resuscitated and they can still experience further tissue injury.

03:28 Now hyperthermia is always a topic that comes up.

03:31 Now the patient may develop hypothermia.

03:33 They may be in really cold water.

03:35 There's really mixed effects on how this impacts the patient's brain function.

03:40 It could be very protective because it might protect the brain if they're in very cold water. Now when it comes to fresh water or salt water, the distinction doesn't really matter. Clinically, it's all bad to be in the lungs.

03:53 As a nurse, it's important that you understand the risk factors for drowning.

03:57 This will help you more safely treat patients and educate patients and families.

04:01 So, one of the biggest risk factors is age.

04:04 Children under five years and adolescents 15 to 19 years.

04:08 The male gender is also a risk factor, because there's approximately a 2 to 1 ratio to females that you're more likely to see a male drowning patient.

04:18 The other challenges can be lack of supervision for children, lack of barriers around a swimming pool, which also goes into lack of supervision.

04:25 Also, alcohol use and water are not a good combination, and we know that up to 70% of adult drownings do involve alcohol.

04:35 Now the adolescents, they have that risk-taking behavior.

04:39 So anyone with risk taking behaviors is at risk for drowning and particularly our adolescent clients.

04:45 Maybe the client can't swim very well and they get in over their head for lack of a better term. Or they may not understand water safety or they may have a seizure disorder. Did you know that drowning is a leading cause of death in people with epilepsy? Now, patients can also have underlying cardiac conditions.

05:04 They can have long LQTS syndrome, arrhythmias or some structural heart disease.

05:08 This can make them a greater risk for drowning.

05:11 Also, clients who have autism spectrum disorder, especially if they are wandering or an elopement, risk.

05:17 And sadly, even clients with a low socio-economic status may be at an increased risk for drowning if they did not have access to water and swimming lessons. And as we wrap up the risk factors, I have three more I wanted to talk to you about. You may or may not have been exposed to these before.

05:35 The first one of these last three is flooding and natural disasters.

05:40 The second one, if the client is immersed in cold water, that makes them just incredibly incapacitated.

05:46 That is extremely cold water.

05:49 It definitely increases their risk for drowning.

05:51 And the last one is if the client has had a prior drowning event.