Investigation of IV Acetaminophen versus Length of Stay

nick · March 9, 2018, 11:00pm

Hi all!

We’re hoping to take a look at IV acetaminophen use. Specifically, whether post-surgical use of IV acetaminophen reduces length of stay. E.g., compare patients who got opioids with IV acetaminophen compared to opioids without IV acetaminophen. There is a paper on an inpatient database that claims yes:

Ryan N. Hansen, An Pham, Scott A. Strassels, Stela Balaban, and George J. Wan. Comparative Analysis of Length of Stay and Inpatient Costs for Orthopedic Surgery Patients Treated with IV Acetaminophen and IV Opioids vs. IV Opioids Alone for Post-Operative Pain. Adv Ther. 2016; 33(9): 1635–1645.

Saving .7 days (unadjusted analysis) or .5 days (using an instrumental variable) quantified by average length of stay. We wonder if we can do a better analysis. Maybe use a cox proportional hazards model for discharge, largely because we have that software coded. Use propensity score stratification to match the groups based on information before surgery plus what surgery they had.

We welcome input and we plan to create a protocol.

rchen · March 9, 2018, 11:55pm

Interesting study! Certainly agree that research into non-opioid pain control is an important topic, particularly now with the growing epidemic

Why IV acetaminophen specifically? Theoretically, if these are all inpatients, we should be able to accurately identify both IV and PO formulations fairly well. Why not expand to acetaminophen in general or add another comparator group on oral meds?

I ask because when I was at UCSF, we weren’t allowed to use IV acetaminophen (I think because it’s much more expensive) unless the patient clearly cannot take PO. While that may be true of some post-surgical pts, many can tolerate oral meds (and one effective pain regimen I liked to use was just scheduling oral Tylenol around-the-clock instead of on a PRN basis)

Jonathan_Slaughter · March 10, 2018, 12:45am

I think such a study would be very interesting in the postoperative setting. IV ketorolac (nonsteroidal anti-inflammatory) is often used, but I wonder about renal side effects especially in the neonates I take care of in the neonatal ICU. We often schedule IV acetaminophen for a few days (bowel surgery patients usually cannot take anything by mouth (NPO) for at least several days postoperatively and many patients are too sick to do so in the first day or so postoperatively. It would be nice to reduce opioid use postoperatively and I wonder if IV acetaminophen might be at least non-inferior to ketorolac, especially in patients with a renal contraindication.

hripcsa · March 10, 2018, 11:15am

For postop, could do a three-arm study: IV acetaminophen, IV ketorolac, none (which could include rectal acetaminophen). Nick’s setup recognizes the extra cost of IV acetaminophen and compares to usual treatment, which might include ketorolac. And could look at opioid abuse as a secondary outcome. The problem with that is that inpatient databases may be best at knowing IV acetaminophen timing and surgery, but they won’t know long term opioid abuse.

George

PaolaSaroufim · March 12, 2018, 3:28pm

Very interesting study! I proposed the opioid epidemic topic for the face
to face meeting . Specifically to look at the opioid dependence as primary
outcome in post op patients.
And yes, there was a shortage of IV acetaminophen that is why the cost was
extremely expensive (and use in hospitals was restricted)
I found the following studies similar to what Nicholas Tatonetti proposed:

their conclusion: Decreased opioid consumption and enhance recovery with
the addition of IV Acetaminophen in colorectal patients: a prospective,
multi-institutional,… - PubMed - NCBI

IV acetaminophen helps to reduce opioid consumption for patients undergoing
colorectal surgery. Additionally, there appears to be a shortened length of
hospital stay, better pain control, reduced time to return of bowel
function, and lower rate of post-operative ileus in patients receiving IV
acetaminophen.

their conclusion: Impact of Intravenous Acetaminophen on Lengths of Stay
and Discharge Status after Total Knee Arthroplasty. - PubMed - NCBI

This study demonstrated that TKA patients who received IV acetaminophen
were associated with a significantly shorter hospital LOS as well as being
discharged home and fewer patients had to go to SNF. This may lead to a
reduction in the total cost of health care, while, at the same time,
decreasing the resource use in patients who undergo TKA.

I hope this helps !
Best,
Paola Saroufim

nick · March 19, 2018, 2:59pm

It’s IV acetaminophen specifically because it is expensive and the hypothesis is that the IV formulation is actually superior to PO. Our hospital, for example, is reviewing it for the formulary – asking if it’s worth the costs.

RachelW · March 28, 2018, 12:20pm

Hey All,

I’m very interested in this area and would love to help. I’ve done some research in this area (acetaminophen) and have learned that channeling (systematic prescribing based on prior medical history in a way that may effect the study outcome) may play a big role. I think it would be interesting to include both IV and oral forms, but it might be important to look at them separately since those being administered IV may be in poorer health or have had more invasive surgery than those given oral forms. How we control for confounding will be important, though I realize we may be limited in a hospital setting by not having a very long patient history in the data.

I’d love to help with the protocol.