In this episode I’ll:
1. Discuss an article about the hemodynamic effects of IV acetaminophen in critically ill patients.
2. Answer the drug information question “When should an opioid naive patient receive a continuous basal rate on patient-controlled analgesia?”
3. Share a resource for easily extracting ICD-10 codes from natural text.
Lead Author: Aymeric Cantais
Published ahead of print in the journal Critical Care Medicine
IV acetaminophen is an expensive medication that lacks robust evidence supporting clinically meaningful patient outcomes. An argument I’ve heard for keeping IV acetaminophen on hospital formularies is for use in critically ill patients whose hemodynamics would be improved by the antipyretic effect of acetaminophen. Elevated temperature increases oxygen demand, which can be exacerbated by conditions such as sepsis, respiratory failure, and cardiac disease. Acetaminophen would theoretically reduce oxygen demand in patients with fever. However, a six patient observational study published in 2013 suggested that IV acetaminophen worsens cardiac output and systemic vascular resistance.
The authors of this study sought to assess the incidence of acetaminophen-induced hypotension. 160 patients across 3 ICUs were enrolled in this prospective observational study. The authors defined hypotension as a decrease in the mean arterial pressure of greater than or equal to 15% from baseline.
51.9% of patients experienced hypotension after receiving IV acetaminophen. The nadir mean arterial pressure occurred within 15 to 71 minutes after receiving IV acetaminophen and ranged from 54 to 74 mmHg. Surprisingly, changes in body temperature were not correlated with changes in mean arterial pressure. Among the patients that experienced hypotension, 34.9% required a therapeutic intervention to address the hypotension.
The authors concluded:
Half of the patients who received IV injections of acetaminophen developed hypotension, and up to one-third of the observed episodes necessitated therapeutic intervention. Adequately powered randomized studies are needed to confirm our findings, provide an accurate estimation of the consequences of acetaminophen-induced hypotension, and assess the pathophysiologic mechanisms involved.
While the authors call for additional studies to confirm the findings, I’ve seen enough. Given the lack of clinically meaningful benefit for IV acetaminophen coupled with this finding of frequent hypotension, I won’t be asking to have IV acetaminophen back on formulary anytime soon.
Drug information question
Q: “When should an opioid naive patient receive a continuous basal rate on patient-controlled analgesia?”
A: Almost never!
I discussed PCA use in detail in episode 58. I reserve basal rates on PCAs for patients who are not opioid naive. Otherwise, it is easy for an opioid naive patient to receive too much opioid and experience over sedation or respiratory failure. I’ll make occasional exceptions to this personal rule, such as:
1. Patients who sleep through the night without pushing their button and awake in pain; these patients can get a nighttime only basal rate.
2. Patients with unusual circumstances causing severe, prolonged pain – such as a thoracic surgery patient who was not eligible for an epidural.
Hat tip to the healthcare IT news and opinion blog HIStalk for talking about the resource for this episode: Text2codes. If your physicians are anything like mine, they’ve been grumbling about the challenges of coding using ICD10. This amazing program uses natural language processing to extract ICD-10 codes from progress notes and history & physical documents. If you know someone who is having trouble with ICD-10 coding, consider telling them to check out text2codes.
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.