Roukis TS. Bacterial skin contaminationbefore and after surgical preparation of the foot, ankle and lower leg in patients with diabetes and intact skin versus patients with diabetes and ulceration: a prospective controlled therapeutic study.   J Foot Ankle Surg. 2010 Jul-Aug; 49(4): 348-356.   (PubMed ID: 20610202)

WHY did the authors undertake this study?
There are numerous reasons why surgical intervention to the lower extremity results in higher postoperative infection rates (and the author does an excellent job of outlining these in his introduction).  The goal of this study was to specifically exam one surgical preparation technique in two different patient cohorts.

HOW did they attempt to answer this question?
Following an extensive literature review of different surgical preparation techniques, the author concluded that the best available technique is a scrub with chlorhexidine gluconate (4%) solution followed by painting with ethyl alcohol and iodine (1%) topical solution.      

A total of 30 diabetic patients were prospectively enrolled into two groups:  (1) Patients undergoing elective foot and ankle surgery with an intact epithelium and (2) patients undergoing emergent/nonelective surgery with an ulceration.   

The primary outcome measure of this study was qualitative aerobic cultures taken before and after surgical preparation from 3 specific sites:  (1) hallux nailfold, (2) interdigital spaces, and (3) anterior tibia.

WHAT were the specific results?
There was a significant reduction in both the number of positive cultures and the number of bacterial isolates following surgical preparation in both groups.  The two most common bacterial organisms isolated were methicillin-resistant Staphylococcus epidermidis and methicillin-sensitive Staphylococcus epidermidis.    

HOW did the authors interpret these results?
From these results, the author concluded  that this surgical preparation technique was effective in diabetic patients both with and without ulceration.  However, he recommends additional protective measures against infection given the post-scrub findings.

Frisch A, Chandra P, Smiley D, Peng L, Rizzo M, Gatcliffe C, Hudson M, Mendoza J, Johnson R, Lin E, Umpierrez. Prevalence of clinical outcome of hyperglycemia in the perioperative period in noncardiac surgery.   Diabetes Care.  2010 Aug; 33(8): 1783-1788. (Pubmed ID#: 20425798)

WHY did the authors undertake this study?
Perioperative management of hyperglycemia is one of my favorite topics.  The results of the Portland Diabetic Project have been eye-opening, and have established significantly higher morbidity and mortality rates with only minimal increases in perioperative glucose levels following cardiac surgery.  These results have been replicated in other situations of cardiac surgery and nearly all patients in the ICU.  The objective of this study, however, was to investigate the effect of perioperative hyperglycemia in general surgery patients. 

HOW did they attempt to answer this question?
The primary outcome measures of this study were the 30-day mortality rate, length of hospital stay, and a variety of known post-surgical complications following any general (non-cardiac) surgery.  Over 3000 consecutive patients were analyzed over a 6-month period from a single tertiary academic hospital. 

WHAT were the specific results?
Higher perioperative blood glucose levels were associated with statistically significant higher levels of 30-day mortality, length of hospital stay, and length of ICU stay, as well as post-operative cases of pneumonia, systemic blood infection, urinary tract infection, acute renal failure, and myocardial infarction. 

HOW did the authors interpret these results?
Based on these results, the authors conclude that perioperative hyperglycemia may lead to untoward effects following any general surgery, and should be aggressively treated in the perioperative period. 

Let’s take a closer look at the topic of a clearly stated hypothesis as it applies to these articles.  One of the first things that just about everyone does when they are trying to decide whether or not to take the time to read an article is simply to browse through the abstract.  The format of an abstract differs slightly based on which journal you are reading, but just about all abstracts provide a brief summary of the introduction, methods, results and conclusions of an article.  While this information is obviously important, I will usually attempt to find and read the hypothesis before even reading the abstract.  I’ll show you how this is often easier to do then you would think. 

Everyone remembers the concept of a hypothesis from grade school, but a general definition from a medical literature critical analysis standpoint is a clearly stated clinical question or objective of a study.  In other words, why did the authors take the time to design a study, collect data, perform statistical tests, write up the results, and go through the often tedious peer-review process?  What was the question that they were trying to answer?  This is the piece of information that I want to know as a critical reader before I decide whether or not to take the time to read through an article.  Once I know the hypothesis, I can decide for myself if I have similar questions, or if I even care about the answer to this question. 

This information is generally very easy to find.  In most articles, the hypothesis/objective/clinical question is found as the last sentence or paragraph of the “Introduction”, right before the “Materials and Methods” section.   So right after I read the title of an article, I flip to the “Materials and Methods” section, and then read the paragraph/sentence immediately preceding it.  If I am interested in the answer to this clinical question, then I go back and read through the abstract and introduction.

Both of our articles from this PJC have clearly stated hypotheses, but only one of them follows this general rule.  Let’s examine the Frisch et al hyperglycemia study first.  If I look to the “Research Design and Methods” section found on 1783, I can immediately find the sentence preceding it as the last sentence of the introduction:  “We hypothesized that general surgery patients with perioperative hyperglycemia would experience higher hospital complications and mortality compared to patients with normal glucose levels.”  That sounds like something that I am interested in, and I would like to see the results of this investigation. 

The Roukis article throws us a little curveball however.  The last paragraph before the “Patients and Methods” section sets us up for a great clinical question.  He tells us that surgical infection is particularly a problem in the lower extremity, and that there numerous ways that bacteria can be eliminated preoperatively, but then the article immediately jumps into “Patients and Methods” without defining a question or hypothesis.  It isn’t until 4 pages later that we readers get a separate section detailing the “prospective, controlled therapeutic study hypothesis” on the bottom of page 352.  The hypothesis is still very clearly defined, it’s just not found where we typically expect to find it.