This should help most medic students.
Above: how Right Side & Left Side heart failure presents.
Middle: most of the drugs you will see when it comes time for your Nat-Reg Practicals. Know the trade & generic names, routes & Doses.
Bottom: mnemonics for your anti-arrhythmic drugs.
have significant damage to the muscles that control respiration
are paralyzed from a drug that prevents those muscles from working (like during
lungs are so damaged/full of fluid that the muscles aren’t strong enough (or have become too exhausted) to
pull air in/keep fluid from building up further (this can be for many reasons,
the most common being severe burns, pneumonia, bronchiolitis in children, cancer, and poorly controlled right-sided heart
Scenarios where this might be applicable in fanfiction:
Character receives a gunshot/stab wound to the upper abdomen, where the diaphragm is pierced or otherwise badly damaged.
Character is envenomated by a blue-ring octopus or some other paralyzing neurotoxic venom.
Bow-and-Arrow-themed superhero ironically receives a typically lethal dose of curare (a personal fav).
Character sustains severe burns with suspected inhalation injuries (burns in the lung) and their lungs are swelling/filling with fluid.
I’m going to talk about ventilators for a second before getting into the meat of your question. There are two distinct types of mechanical ventilation. Positive Pressure (PP) Ventilation and Negative Pressure (NP) Ventilation.
PP Ventilation is what most people think of when they think of a ventilator. This type of ventilator consists of a tube that either goes down a patient’s throat or through a hole in their windpipe called a tracheostomy. The tube is connected to a computerized and mechanized reservoir of air that pushes a set quantity of air through the tube into the patient’s lungs. Patients then (usually) breathe out passively. These can be set to “breathe” either a certain number of times per minute or to detect the beginning of a patient’s breath and only “assist” with the breath instead.
Here is a video that demonstrates breathing and shows how this machine typically works. These machines look like this:
In NP ventilation there is no tube going into the patient’s lungs. This machine works by changing the air pressure around the patient’s body, causing the chest to expand and take in air. One familiar example of this is the iron lung. While these are not typically used today, one of their descendants, called the biphasic cuirass ventilator (BCV), is (link is to a video). This is like a wearable mini iron lung and looks like a turtle shell:
It is possible for people to be on both types of ventilators while awake.
Trauma patients usually need to be on PP ventilation, and will be at least partially sedated during their time on a vent, on painkillers, and anti-anxiety drugs. This means they usually aren’t particularly “with it”during this time. The sedatives and anti-anxiety drugs are used with PP ventilation because the experience can be very scary and uncomfortable for patients (think of not being able to move while your brain is telling you you’re suffocating, even though you aren’t, combined with pain from other injuries, unfamiliar surroundings/noises from the machine/hospital in general). Most people wouldn’t want to experience/remember that. Painkillers would be less for the ventilation itself and more for other injuries, but could still have a significant impact on consciousness.
That being said, the moment in a fanfic where a character wakes up on a PP vent and is told “Don’t fight it!” can be accurate in limited circumstances. In this situation, if the patient is fighting the ventilator, it may be time to change the vent setting to one where the patient initiates the breaths (see above). If the character’s breathing still needs to be entirely mechanically controlled for another reason, doses of sedative medication may need to be changed. Irl, it would be unacceptable to simply leave a patient in a condition where they were constantly fighting the ventilator. Even if the patient was calm and trying really, really hard not to fight it, it would likely still be a mentally and physically exhausting and uncomfortable experience for them.
People who are more used to being on a ventilator (long term patients) may need fewer interventions/drugs to stay comfortable. It is possible to “get used to it” over time. Those who are conscious/calm enough to communicate typically can do so through writing or a book/board with pictures they can point to that help express their needs/answer questions. These patients can answer questions like “What is your name and birthday?” “What year is it?” and “Point to the picture of a dog” In order to determine mental status.
Measuring mental status with sedated patients is done through observational scales like this one:
Patients on NP ventilation have no need for paralytic or sedative drugs to initiate or continue ventilation. They can talk and even eat normally while wearing a BCV, and movement is only slightly restricted. However, it is much less likely that a BCV would be used in a trauma situation because it requires an intact chest cavity to work, and because it does squeeze and pull at the chest, it could cause more pain and damage to injured bones and muscles..
How does congestive HEART failure affect the LUNGS?
The heart pumps blood around the body. When it becomes inefficient, like in mitral valve disease, while some blood is still pumped forward, some also flows backwards. This backwards flow, often causing turbulence which is heard as a murmur, means there is higher blood pressure before the dodgy valve than there should be.
There’s only so much blood volume a patient’s organs can handle. If this is a chronic problem then the liquid of the blood will spread into surrounding tissue. If it’s right sided heart failure then that fluid usually ends up causing a swollen liver and ascites. In left sided heart failure, like the picture, that fluid ends up accumulating in the lungs.
Because the lungs are like a sponge and coated with surfactant, the fluid and air mix and are often coughed up as foamy bubbles, with blood staining as it gets worse.
You can accidentally accomplish the same thing by giving a patient too much intravenous fluid therapy too quickly.
When the patient is not breathing quickly (i.e dead) then the fluid isn’t mixed with air, doesn’t foam and just pours out.
While heart patient can just drop dead, usually they’re drowning.
Right-sided heart failure occurs when the right ventricle is not pumping blood into the lungs sufficiently. Because of this, blood backs up into the peripheral circulation –> patient develops peripheral edema and weight gain.