Mieras JN, Singleton TJ, Barrett SL. Contralateral peak plantar pressures with a postoperative boot: a preliminary study. J Am Podiatr Med Assoc. 2011 Mar-Apr; 101(2): 127-32.   (PubMed ID: 21406696)

WHY did the authors undertake this study?
Podiatric physicians often prescribe orthopedic walking boots to off-load, protect and immobilize a lower extremity affected by pathology. However, the resulting limb length discrepancy and increased pressure on the contralateral foot may cause undue complications. The objective of this study was to determine the effect of wearing an athletic shoe or modified surgical shoe on the contralateral extremity when an orthopedic walking boot is utilized.

HOW did they attempt to answer this question?
The primary outcome measure of the study was peak calcaneal plantar pressure as assessed with an F-Scan device. Twelve participants completed 4 trials of footwear combinations:  (1) bilateral barefoot, (2) CAM walker left/Barefoot right, (3) CAM walker left/Athletic shoe right, and (4) CAM walker left/Modified CAM walker right.

WHAT were the specific results?
Statistically significant decreased pressures were found on the contralateral extremity with use of either an athletic shoe or modified CAM walker when compared to barefoot walking. No statistical difference was found in peak plantar pressures between these two groups (athletic shoe vs. modified CAM walker).

HOW did the authors interpret these results?
From these results, the authors concluded  that the use of an athletic shoe worn on the contralateral extremity when a orthopedic walking boot is utilized is probably a reasonable option.

Dougherty PP, Klein-Schwartz. Unexpected late rise in plasma acetaminophen concentrations with change in risk stratification in acute acetaminophen overdoses.  J Emerg Med.  2011 Jun 28 Epub.

WHY did the authors undertake this study?
A nomogram has long been utilized in the treatment of acute acetaminophen overdoses within the fields of emergency and general medicine. Generally speaking, a single plasma acetaminophen concentration (PAC) is measured and the need for antidotal therapy is based on that one PAC alone. Recently however, it has been noted that PAC values may peak later than expected, especially when considering extended-release products. The authors of this study aimed to identify risk factors for patients in whom this later PAC spike may occur, and for whom the interventional nomogram may not be effective. 

HOW did they attempt to answer this question?
A retrospective study design was utilized to identify patients from a poison control center database who had an acute acetaminophen overdose and at least two plottable PACs. Descriptive characteristics of the patient’s care were recorded. 

WHAT were the specific results?
Twenty patients were identified who initially would not have required antidotal therapy based on a single PAC, but who later peaked into the treatment level with a subsequent PAC. Two patients eventually developed hepatotoxicity, and one died.

HOW did the authors interpret these results?
Based on these results the authors concluded that utilizing the interventional nomogram with a single PAC measurement cannot always predict toxicity following acute acetaminophen overdose.   

Let’s take a closer look at the topic of making numbers more practical, particularly as it applies to the Dougherty and Klein-Schwartz acetaminophen overdose article.  This topic seemed relevant with the recent important change in daily dosing recommendations put forth by Johnson & Johnson.  In short, the company that manufactures acetaminophen has recommended lowering the maximum daily dose from 4 grams to 3 grams.   Changes in packaging will start in the fall of 2011, and I expect pills with new dosages will quickly follow.  I’ve always been interested in pain management for whatever reason, and have written a little on the topic (article 1, article 2, & article 3), so let’s take a closer look at how to make this change more practical in our everyday lives. 

Aceteminophen can be one of our most basic and most important adjuvant agents with respect to perioperative pain management.  Extra-strength Tylenol is currently dosed as a 500mg pill.  So previous to the recent announcement, a patient could take 4000/500 = 8 pills in a single day without exceeding the daily maximum dose.  Tylenol takes advantage of this by recommending up to 2 pills q6 hours.  With the new changes, a patient can now only take 3000/500 = 6 pills in a single day without exceeding the daily maximum dose.  So, from a practical standpoint, I could still write a prescription for 2 pills q8 hours prn.  A small, but important and practical change to my normal prescribing practices. 
               
[As an aside, I would assume that the manufacturer would continue to prefer to sell 8 pills a day instead of 6 pills a day, so don’t be surprised if we see Extra-strength Tylenol dosed in the ballpark of 3000/8 = 375mg in the near future!] 
               
How about with our narcotic pain medications that we typically use for postoperative pain management?  Percocet contains 325mg of acetaminophen in a single pill.  So, simply from an acetaminophen standpoint, I can only safely recommend up to 3000/325 = ~9 pills in a single day.  This roughly translates to no more than 2 pills q6 hours or 1 pill q4 hours.  From a practical standpoint, I plan using this information in the outpatient setting by writing for no more than 8 pills a day, and recommending q6 hour dosing instead of q4 hour dosing.  This is also important for my residents in the hospital and for other inpatient dosing.  I need to be very careful in terms of my order writing in terms of the number of pills and the frequency.  I already discourage residents from writing any ranges (such as “1-2 pills” or “4-6 hours”), and now I will strongly encourage them to stick with q6 hour dosing.  I also need to be very careful in terms my in-patient order writing in case there is a standing order for acetaminophen prn fever.  Taking another dose of acetaminophen for fever would decrease the maximum number of pain pills even greater depending on the specific dose.  Again, mostly for the residents or those of us who have busy in-patient services, it would probably be worth fielding the phone call about a patient’s fever instead of blindly writing a standing order. 
               
Vicodin is even more challenging.  Each Vicodin pills contains 500mg of acetaminophen, so I can only safely recommend up to 3000/500 = 6 pills in a single day.  From a practical outpatient standpoint, I will no longer write for more than 6 pills a day, and need to consider writing 1 pill q4 hours or 2 pills q8 hours.  Obviously Vicodin has the same considerations for residents and other in-patient services. 
               
None of this makes much sense from a pain management standpoint unfortunately.  In theory, it would be better to have smaller doses more often, instead of stretching the frequency out to every 6 hours for example.  Additionally, I like having standing acetaminophen as an adjuvant pain medication, and would prefer to not write for simply oxycodone for example.  This will probably force me to re-examine some of my perioperative pain management strategies to be honest with you. 

Manufacturers are smart, so it’s possible and probable that all pills simply decrease the dose of acetaminophen over the next year and this math becomes a moot point, but sometimes you have to break out your calculators and do a little simple division to make numbers more practical for our everyday practices.