I put this case up because I wanted to talk about lasix and nitro in acute pulmonary edema (APE). Imho, there are two intubation-saving drugs – epi in asthma, and lasix in APE. I’m a fan of lasix. Once there is fluid in the lungs, lasix is the best way to get it out quickly so that patients can breathe better. It’s not a practice based on RCTs, but you don’t always need a study to support what you do. If you’ve given lasix a million times before and you see patients look so much better every time, that’s sufficient. There’s a study that suggests that time-to-lasix reduces mortality in patients with APE (https://www.ncbi.nlm.nih.gov/pubmed/28641794).
IV nitro in APE is useful, but what dose do you start it at? 10 mcg/min is a teeny tiny dose, and many people start at 80, 100 or higher. I don’t do that. I give sublingual nitros, and when I start a ntg drip, I start at a low dose (typical 20) and titrate up. This is my general practice with all medications (with the possible exception of pain killers) – start low and give more if it’s not enough. As far as lasix – I give the home dose of lasix iv. If the patient isn’t on lasix at home, I give the lowest dose: 20 mg.
Some people debate about the importance of ntg or lasix. They are both important in APE. It’s like debating albuterol v steroids in asthma. They are both important. Use them both.
What’s the danger in starting a ntg at a high dose? Dropping the BP. If the patient has a bad heart, a bad valve, or both, you may do the patient serious harm.
Most patients with HFpEf aka diastolic failure don’t drop their BPs with high doses of iv nitro. This patient was started at 80, and her blood pressure tanked quickly. The ntg was turned off and her BP came up. If the patient wasn’t monitored closely, it could have been bad. The unexpected BP response to the iv nitro should be a warning. The patient may not have what you think she has, her history of HFpEf / diastolic failure may be incorrect. She may have isolated right heart failure (aka cor pulmone) or she may have HFrEf (aka systolic heart failure).
Most cases of acute pulmonary edema (APE) are slam dunks. It is a clear-cut diagnosis based on physical findings of L heart failure (rales, respiratory distress, hypoxia, s3), R heart failure (peripheral edema, jvd), and the cxr. Thus, most patients do not require a bnp or a pulmonary sono. When in doubt, a bnp and a pulmonary sono can confirm the dx of APE. However, an S3 gallop is diagnostic of heart failure.
The cxr on this patient was not such a sure-thing for APE, so we did a pulmonary sono. The patient had multiple B-lines in all lung fields. The diagnosis of APE was fairly certain. Her bnp came back in the 2000s. During her admission, her echo showed an Ef of 30%. Thus, she wasn’t a great candidate for a big dose of ntg.
As far as oxygen and intubation, the answer is impossible without seeing the patient. The decision to use nasal cannula, a non-rebreather, bipap, or intubation is based largely on the patient’s respiratory distress / clinical appearance, something that can’t be translated on paper. Our patient was placed on bipap and once she diuresed and looked better, changed to nasal cannula. She had an uneventful hospitalization otherwise.