Category Archives: General

How To Avoid Missed Injuries

I’ve just spent two days here looking at the phenomenon of “delayed diagnosis” or missed injury. I believe that there are only two fundamental reason why this occurs:

  • Insufficient diagnostic technique – A good physical exam and/or specific diagnostic techniques were not performed. Or rarely, the injury cannot be readily detected by existing techniques and technology. The former is usually the real problem, and may be an issue with either the physical exam completeness and/or technique, or judgment used to obtain the appropriate diagnostic test. Example 1: a penetrating injury to the back is missed because the patient is not logrolled to examine this area. Example 2: a spine fracture is missed in an elderly patient with a fall from standing because the back pain found on physical exam is evaluated only with conventional imaging of the spine, not CT.
  • Failure to recognize the injury – The injury was actually identified on a test, but was not appreciated by the clinician. Example 1: the radiologist may not have appreciated and reported out a subtle anomaly in the cervical spine imaging. Example 2: you fail to check you patient’s lab tests and miss a sudden spike in serum amylase or lipase the day after your patient was kicked in the epigastrium by a horse.

So what can you do to avoid this potential problem? Here are some tips:

  • Admit that it can really happen to you. If the missed injury rate at your center is off the low end of the bell curve (< 5%) then you are either really good or really blind. You’d better take a close look at your performance improvement process, because you may be fooling yourself.
  • Adopt a firm definition of “delayed diagnosis.” Basically, you need a time frame after which a new diagnosis is considered “delayed.” It should be a reasonable time interval after the patient has left the ED. If it’s too short an interval (e.g. once they leave the ED), your number will be unnecessarily high. If it’s too long (days and days later), then significant morbidity may occur that you don’t account for. Most centers have adopted 24, 36, or 48 hours after patient arrival.
  • Implement a tertiary survey process. This is a complete physical re-examination followed by a review of all diagnostic studies (lab and radiology) that have been performed. This exam needs to be dated and timed to ensure that it is performed within the time frame noted above. If a new finding is discovered on the tertiary survey, it is not considered a delayed diagnosis. If found after the survey (or after the pre-determined time interval), it is and must be entered into your performance improvement process.
  • Be paranoid. I hate the phrase, “maintain a high index of suspicion” because it’s meaningless. It’s like those stupid “start seeing motorcycles” bumper stickers. You can’t see what you can’t see. But you can be suspicious all the time, constantly looking for the inevitable clinical surprises of trauma care. 

Related posts:

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Are There Really More Missed Injuries After Hours?

Yesterday, I wrote about the usual reasons for delayed diagnosis: insufficient diagnostic technique or insufficient recognition. What about time of day? A recent paper looked at the correlation between admission time and rate of missed injuries.

The work was done at a large teaching hospital and Level I trauma center in Australia. A large number of patients were reviewed over an 11 year period. The study was complicated slightly by the implementation of a dedicated trauma unit in the middle of the study period, but the authors stratified their groups to account for this. 

Results were stratified by time of admission: office hours vs after-hours vs weekends. Missed injuries were defined as those found after completion of the primary and secondary surveys. The overall statistical treatment appeared to be robust.

Here are the factoids:

  • A huge number of patients (53,000) were reviewed. This is a busy place!
  • There were 2519 missed injuries in 1262 patients (2.4%) [low!]
  • Missed injuries occurred during office hour admissions in 2.2%, after-hours in 2.6%, and on weekends 2.5% of the time
  • The increased incidence of delayed diagnosis in after-hours admits was marginally significant (p = 0.048)
  • Missed injuries appeared to have increased over time, and were 1.34 times more likely at the end of the study period vs the beginning
  • Thoracic spine and abdominal injuries were most the commonly missed

Bottom line: Hmm, time of day was not in my list of reasons for missing diagnoses. What gives? If you read the article closely, the trauma service at this hospital was staffed with a higher number of trainees after hours and on weekends than during office hours. It was also noted that incomplete physical examination was thought to be a factor in many of the delays. Most likely, both of my listed reasons were in play here. Inexperienced clinicians and insufficient examination are both major factors. And what about the increase in missed injuries over time? Midway through the study, the hospital implemented a dedicated trauma unit, and a tertiary exam became routine. This identified more injuries after the primary and secondary surveys were complete. 

Tomorrow I’ll talk about strategies to drop the incidence of missed injury.

Reference: Office hours vs after-hours: do presentation times affect the rate of missed injuries in trauma patients? Injury 2015, in press.

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Missed Injury / Delayed Diagnosis

Missed injuries (or delayed diagnosis in polite conversation) are the bane of any trauma program.Trauma professionals want to know that they’ve identified all significant injuries in their patients so no future harm will occur due to them.

But what exactly is a missed injury? The definitions tend to vary a bit, which is why their incidence varies so widely in the literature (1 – 39%). The simplest way to describe one is any injury that is identified after a set amount of time. But what is a reasonable time frame? Some define it as the time spent in the emergency department (highest incidence). Others count any injury found after a predetermined period of time (typically 24-48 hours). Some use even longer time intervals, so they obviously look the best and have the lowest incidence.

And what are the factors that contribute to us “missing” these injuries? As you can imagine, there are quite a few, but they boil down to two major categories:

  • Inadequate diagnostic technique (physical exam and/or technology) – I can’t see it
  • Inadequate recognition – I didn’t think of it

A good physical exam with the focused use of appropriate imaging is paramount. Sure, you could use a shotgun approach and just scan everything. The problem is that CT scans have limitations, but we tend to forget that. So we believe that if we don’t see anything on scan, it must not exist. Wrong! The physical exam may pick up suspicious findings that tell the clinician that a specialized study is necessary to rule a potential injury out.

The failure to recognize that an injury is present can occur with everyone that “touches” the patient. The EMT or physician may not appreciate a subtle injury. The radiologist may miss a problem on the images they read. The surgeon might even fail to notice another injury separate from the one she is operating for. Obviously, experience plays a large part in this factor. Students will fail to appreciate a potential injury that a senior clinician will detect rapidly. 

What to do about it? Tomorrow, I’ll review a recent paper that tries to correlate missed injuries with time of admission. And on Friday, I’ll discuss some strategies to try to help keep it from happening to you.

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First, Read The Paper. THEN THINK ABOUT IT!

This is a perfect example of why you cannot just simply read an abstract. And in this case, you can’t just read the paper, either. You’ve got to critically think about it and see if the conclusions are reasonable. And if they are not, then you need to go back and try to figure out why it isn’t.

A study was recently published regarding bleeding after nonoperative management of splenic injury. The authors have been performing an early followup CT within 48 hours of admission for more than 12 years(!). They wrote this paper comparing their recent experience with a time interval before they implemented the practice.

Here are the factoids. Pay attention closely:

  • 773 adult patients were retrospectively studied from 1995 to 2012
  • Of 157 studied from 1995 to 1999, 83 (53%) were stable and treated nonoperatively. Ten failed, and all the rest underwent repeat CT after 7 days.
  • After a “sentinel delayed splenic rupture event”, the protocol was revised, and a repeat CT was performed in all patients at 48 hours. Pseudoaneurysm or extravasation initially or after repeat scan prompted a trip to interventional radiology.
  • Of 616 studied from 2000-2012, after the protocol change, 475 (77%) were stable and treated nonoperatively. Three failed, and it is unclear whether this happened before or after the repeat CT at 48 hours.
  • 22 high risk lesions were found after the first scan, and 29 were found after the repeat. 20% of these were seen in Grade 1 and 2 injuries. All were sent for angiography.
  • There were 4 complications of angiography (8%), with one requiring splenectomy.
  • Length of stay decreased from 8 days to 6.

So it sounds like we should be doing repeat CT in all of our nonoperatively managed spleens, right? The failure rate decreased from 12% to less than 1%. Time in the hospital decreased significantly as well.

Wrong! Here are the problems/questions:

  • Why were so many of their patients considered “unstable” and taken straight to OR (47% and 23%)?
  • CT sensitivity for detecting high risk lesions in the 1990s was nothing like it is today.
  • The accepted success rate for nonop management is about 95%, give or take. The 99.4% in this study suggests that some patients ended up going to OR who didn’t really need to, making this number look artificially high.
  • The authors did not separate pseudoaneurysm from extravasation on CT. And they found them in Grade 1 and 2 injuries, which essentially never fail
  • 472 people got an extra CT scan
  • 4 people (8%) had complications from angiography, which is higher than the oft-cited 2-3%. And one lost his spleen because of it.
  • Is a 6 day hospital stay reasonable or necessary?

Bottom line: This paper illustrates two things:

  1. If you look at your data without the context of what others have done, you can’t tell if it’s an outlier or not; and
  2. It’s interesting what reflexively reacting to a single adverse event can make us do.

The entire protocol is based on one bad experience at this hospital in 1999. Since then, a substantial number of people have been subjected to additional radiation and the possibility of harm in the interventional suite. How can so many other trauma centers use only a single CT scan and have excellent results?

At Regions Hospital, we see in excess of 100 spleen injuries per year. A small percentage are truly unstable and go immediately to OR. About 97% of the remaining stable patients are successfully managed nonoperatively, and only one or two return annually with delayed bleeding. It is seldom immediately life-threatening, especially if the patient has been informed about clinical signs and symptoms they should be looking for. And our average length of stay is 2-3 days depending on grade.

Never read just the abstract. Take the rest of the manuscript with a grain of salt. And think!

Reference: Delayed hemorrhagic complications in the nonoperative management of blunt splenic trauma: early screening leads to a decrease in failure rate. J Trauma 76(6):1349-1353, 2014.

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How To Read A Stab Wound

Most emergency departments do not see much penetrating trauma. But it is helpful to be able to learn as much as possible from the appearance of these piercing injuries when you do see them. This post will describe the basics of reading stab wounds.

Important: This information will allow some basic interpretation of wounds. It will not qualify you as a forensics expert by any means. I do not recommend that you document any of this information in the medical record unless you have specific forensic training. You should only write things like “a wound was noted in the midepigastrium that is 2 cm in length.” Your note can and will be used in a court of law, and if you are wrong there can be significant consequences for the plaintiff or the defendant. This information is for your edification only.

1. What is the length of the wound? This does not necessarily correspond to the width of the blade. Skin stretches as it is cut, so the wound will usually retract to a length that is shorter than the full width of the blade.

2. Is the item sharp on one side or both? This can usually be determined by the appearance of the wound. A linear wound with two sharp ends is generally a two sided knife. A wound with one flat end and one sharp end is usually from a one-sided weapon. The picture below shows a knife wound with one sharp side.

3. Is there a hilt mark? This can usually be detected by looking for bruising around the wound. The picture below shows a knife wound with a hilt mark.

4. What is the angle? If both edges are symmetric, the knife went straight in. If one surface has a tangential appearance, then the knife was angled toward that side. You can approximate the direction of entry by looking at the tangential surface of the wound edge. In this example, the blade is angling upward toward the right.

5. How deep did it go? You have no way of knowing unless you have the blood stained blade in your possession. And yes, it is possible for the wound to go deeper than the length of the knife, since the abdominal wall or other soft tissues can be pushed inwards during the stab.

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