Monday, October 17, 2005

Stress and Friendly Fire in the OR

On call today, with a light schedule, so I have been able to catch up on my journal reading. I found two articles in the October edition of the Journal of the American College of Surgeons (subscription required but free for medical students). And no, one was not Prognostic Significance of Ploidy, MIB-1 Proliferation Marker, and p53 in Renal Cell Carcinoma; I'm just not that kind of guy.

The first item of interest is takes on a challenging question: the quantification of stress. Entitled Quantification of Surgical Resident Stress "On Call," (by multiple authors from UCSF-East Bay) the article describes measurement of heart rate (with 24 hour Holter monitoring) and WBC levels in interns, junior residents, and senior residents both on and off call. The conclusions reached were:

When heart rate is used as an indicator of combined physiologic and psychologic stress, surgical residents achieve stress levels of tachycardia "“on call."” Surgical residents also exhibit an increase in circulating WBC count "“on call."” Both the degree of tachycardia and the increase in WBC count are inversely related to the level of training. Senior residents cope better with stress "“on call"” than junior residents and interns.
In other words, surgery residents get stressed while on call, and lower level (i.e., less experienced) residents are more stressed than their senior counterparts. This is further illustrated by the amount of 1-hour time periods with heart rates >120 that were seen (emphasis is mine):
Interns had significantly more 1-hour time periods during which their HR was greater than 120 bpm (7.0 ± 1.3 1-hour periods "“on call"” versus 0.3 ± 0.3 "“off call,"” p = 0.003). During the 24-hour "on call"” work shift, some interns had as many as 16 1-hour time periods during which their HR was more than 120 bpm. This is compared with a mean of less than 1 1-hour time period of elevated HR among senior residents "“on call." Senior residents incurred only 0.8 ± 0.5 1-hour time periods during which their HR elevated "“on call" versus 0.4 ± 0.2 off duty (p = 0.5). Junior residents were in the intermediate range, with 6.2 ± 2.6 1-hour time periods of elevated HR "on call"” versus 1.3 ± 0.6 off duty (p = 0.14).
I would love to see some follow-up studies with this tool --- comparing surgery and medical residents, cardiology fellows and GI fellows, etc. Most importantly (to this old man with way too much gray in his beard), what about practicing surgeons --- perhaps one, five, and ten years after residency. Neat stuff overall. Interestingly, the authors pointed out an important side issue to this, namely work hour restrictions (emphasis is mine).
The senior residents who participated in this study trained in a period before Accreditation Council for Graduate Medical Education guidelines on work hour limitations went into effect, so they were exposed to longer work hours in the early phases of their training. In contrast, the interns and some junior residents have always trained under the current Accreditation Council for Graduate Medical Education guidelines. Exposure to longer work hours may have preconditioned the senior residents to respond better to stress "“on call." Preconditioning has been studied in athletes and animal exercise studies. Preconditioning confers a well-documented influence on the cardiovascular system and alters a subject'’s approach to psychologic challenges. As surgeons, constructive preconditioning will play an important role in how we approach critical problems and how we deal with stress.
I freely admit that I am biased; I really, really do not like the current imposition of work hour restrictions on surgery training programs for a whole host of reasons, and this article illustrates one of those reasons.

Which leads me to the second October JACS article in this overly long post: Biliary Injury in Laparoscopic Surgery: Part 1. Processes Used in Determination of Standard of Care in Misidentification Injuries (by Steven Strasberg, MD from Washington Univ. in St. Louis). In discussing opinions about negligence and standards of care in laparoscopic cholecystectomy, Dr. Strasberg employs a great analogy:
... the problem of misidentification might be best illustrated by analogy: identification of an enemy by the military during combat. Every branch of the military has a set of rules for identifying the enemy. The goal is positive or conclusive identification of the enemy. The main purpose is to avoid injury to one'’s own or allied troops. Positive identification is a key element in the rules of engagement, which govern whether an enemy shall be attacked. This system for protection of friendly troops works well in most circumstances, but it can fail. When failure occurs, it seems to be for one of three reasons. The first is that the system is not used or not used as instructed. In some cases this will be due to carelessness and an action below the standard of care will have occurred. The second is that the battle conditions are so severe that even with proper application of the rules, the system will sometimes fail. And the third possibility is that there is an unforeseen flaw in the rules, possibly because of changing conditions of war such that under certain conditions, the system will fail. The second and third conditions result in injuries, which are not from negligence because they can happen as a result of activity of the reasonably prudent soldier. To extend the analogy to cholecystectomy, the cystic duct is the enemy to be correctly identified and the other bile ducts are friendly.
I think that's a great analogy for much of what happens in surgery, and particularly in urgent/emergent/complicated surgery. So, in light of the first study mentioned above, I kind of wonder: is the surgeon who has been to "boot camp" in the training era prior to work hour restrictions better able to handle stressful cases in the OR and avoid "friendly fire" injuries? Or will the next generation of sureons be no different once they get into practice? Time will tell.

(Also, as someone who has no military background, are there "work hour restrictions" at
Camp Lejeune?)