Patients can chew gum immediately before surgery. I guess

A study presented at the American Society of Anesthesiologists (ASA) meeting in October of this year found that patients who chew gum in the immediate preoperative period may safely undergo surgery.

The authors, based at the University of Pennsylvania, found that gum chewing increases saliva production and the volume of fluid in the stomach, but stomach acidity was equivalent to that of non-gum chewers. An article about the study said The mean gastric volume, or total amount of liquid in the stomach, was statistically higher in patients who chewed gum before their procedure (13ml) versus those who did not (6ml). A 7 mL difference might be statistically significant, but surely is not clinically important.

The research differed from previous studies because it involved patients who underwent upper gastrointestinal endoscopy, which enabled the investigators to recover all of the fluid in the stomach for testing. Prior studies had been done using nasogastric tubes, and it was impossible to determine whether all gastric fluid was recovered when the tubes were suctioned.

The study involved 34 gum chewers who were allowed to chew any type or any amount of gum compared to 33 patients who did not chew gum.

Do operating room checklists improve outcomes?

The other day Atul Gawande tweeted the following:

I am not against checklists. When I was a surgical chairman, I implemented and used one in both the operating room and the ICU. They do not add costs and may be helpful.

However, the randomized trial that Gawande referred to does not necessarily settle the issue about whether checklists really do reduce complications and deaths.

The paper, published online in Annals of Surgery [full text here], looked at 5,295 operations done in two Norwegian hospitals. The intervention was a 20-item checklist consisting of three critical steps–the sign in before anesthesia, the timeout before the operation began, and the sign out before the surgeon left the operating room. Using a stepped wedge cluster design, patients were randomized to control or the checklist.

Complications occurred in 19.9% of the control patients and 11.5% in those who got the checklist, a significant difference with p < 0.001.

A look at Table 2 finds that of 27 complications or groups of complications, 14 occurred in significantly fewer patients in the checklist group.

Of the significant 14, a few, such as cardiac or mechanical implant complications, could possibly have been prevented by the implementation of the checklist.

For most of the others, the relationship between the use of a checklist and a post-operative complication is tenuous. How could a checklist possibly prevent technical complications like bleeding requiring transfusion, surgical wound dehiscence, and unintended punctures or lacerations?

Here are a few more of the complications that occurred significantly less frequently in the checklist cohort—urinary tract infection, pneumonia, asthma, pleural effusion, dyspnea, and the nebulous categories of "complications after surgical and medical procedures" and "complications to surgery not classified."

What item on a checklist prevents asthma, UTI or any of those on that list?

Embolism, sepsis, and surgical site infection, three complications one would expect a checklist to impact because of reminders to give prophylactic antibiotics and anticoagulation, did not occur at significantly lower rates in the checklist group.

Even the cardiac complication category is open to question because none of the 5 subcategories (cardiac arrest, arrhythmia, congestive heart failure, acute myocardial infarction) differed significantly between the two groups. Only when the 5 were combined did statistical significance emerge.

In the 300-bed community hospital, checklist use was associated with a significantly lower mortality rate than non-use, 0.2% vs. 1.9% respectively (p = 0.02), but no mortality difference was seen in the 1100-bed tertiary care hospital.

The tertiary care institution enrolled 3,811 patients while the 300-bed hospital contributed 1,083. If more patients had been in the latter group, the difference may have disappeared due to the principle of regression to the mean.

Despite the heightened vigilance associated with an ongoing research project, compliance with checklist use was only 73.4%.

Before you go off on me, I will remind you that I do not oppose checklists. Most things we do in medicine are not based on Class 1 evidence.

Just don't tell me that checklists have been proven to reduce complication rates or save lives.

Preoperative fasting and evidence-based medicine

The other day Mike Blackburn, a South African anesthesiologist I follow on Twitter, posted this: "Colleague just fb’d about a surgeon who said, 'I know we should wait 6 h but she ate at 12 and looks like a fast digester.'"

This was followed by a tweet from someone who calls him- or herself @LessIsMoreMed who said, "funnier still is the lack of evidence re: pre-op fasting" and included links to two references on the subject.

This reminded me of an incident that occurred about three years ago. I was working as a surgical hospitalist and had admitted a patient with acute cholecystitis in the middle of the night. I put her on the add-on OR schedule for that day.

By and by the patient was called for and when I got to the operating room holding area, the anesthesiologist met me with a frown on his face and told me the case would have to be postponed for a minimum of 6 hours.

I asked why. He told me that when he interviewed the patient, he noticed that the patient had a piece of hard candy in her mouth. He informed me that, in terms of gastric secretion, the act of sucking on a piece of hard candy was equivalent to having a eaten a full meal of solid food.