The PCA Fallacy

Hi there 👋🏻

I’ve always had a love hate relationship with patient controlled analgesia(PCA).

It’s such a powerful tool, but the dosing can get complicated fast.

One of the biggest reasons PCA causes problems is that many clinicians start it with this assumption:

“Oh yea! Their pain isn’t controlled. The PCA lets them press the button whenever they want, and therefore they’ll have better pain relief.”

Jinx? That’s why I wrote this week’s newsletter.

Before starting a PCA, you first have to consider whether the patient is opioid naïve or tolerant.

If the patient isn’t on any opioid at home before you start the PCA, the default PCA setting is likely fine.

But if the patient is on chronic opioids, the PCA will only work better if you factor in their baseline opioid use.

Let’s say the patient is on MS Contin 30 mg every 8 hours and oxycodone 10 mg four times a day. Starting IV Dilaudid 0.2 mg every 10 minutes will likely leave them jamming the button for hours because their baseline opioid need isn’t met.

So before concluding the patient is hitting the button too much, here are two references that walk you through how to dose a PCA:

1. Fast Fact

2. MD Anderson

PS: Fun fact — I just learned that PCA is called 病人自控式止痛 in Chinese and じこちょうせつちんつうほう in Japanese.

See you next time,

SP