Nonoperative Management Of Abdominal Stabs: How Long Should We Watch?

Gunshots to the abdomen are a no-brainer that nearly always require operative exploration, but stab wounds are more challenging. They are low velocity, and injury only occurs in the pathway of the knife. It is more likely that inconsequential (or no) injuries occurred. Since exploratory laparotomy (or even laparoscopy) is not a benign procedure, trauma professionals frequently opt for selective nonoperative management (observation) in these cases.

What does observation mean? The patients are kept in the hospital for a set period of time, receive serial abdominal examinations, and get a few repeat lab tests. If the exam changes, the patient is taken to the OR to find out why. If it doesn’t, they are fed and sent home.

But what is the appropriate period of time to observe? One major concern is for the possible hollow viscus injury. Stomach and colon contain fluids that cause prompt peritonitis. But small intestinal content is rather innocuous, with neutral pH, normal concentration, and few bacteria. Peritonitis may not occur for days. Yet most centers send these patients home within 12 to 24 hours of injury.

What is the right answer? The trauma group at LAC+USC in Los Angeles performed a prospective, observational study to try to answer the question. They enrolled all patients with abdominal stab wounds presenting to their center over a three year period. They were generous (and correct) with their definition of the abdomen, including the thoracoabdominal portion up to the 5th intercostal spaces, and the pelvis.

Patients were excluded if they were hemodynamically unstable, or had an evisceration or obvious peritonitis. Most patients received a CT scan, and patients with suspected hollow viscus injury were excluded from the study and taken to the OR. All others were observed in a dedicated unit and were monitored for change in exam, need for blood transfusion, or other event which was recorded for the study.

Here are the factoids:

  • A total of 256 patients met study criteria: 77% had a single stab and 76% had a negative FAST exam
  • There were 46 patients who underwent immediate laparotomy for evisceration (59%), hemodynamic instability (33%), or peritonitis (24%)
  • 81% of patients underwent CT scan, and 13% were taken to OR based on the findings
  • This left 210 patients for nonoperative management
  • Of these, 71 had positive scans and all were due to solid organ injury. One patient failed at 32 hours due to increasing lactate and WBC, but the operation was nontherapeutic.
  • Another 14 patients had equivocal CT findings and two failed at 10 and 20 hours due to small bowel injury discovered by increasing lactate, WBC, change in exam, and air on a repeat CT
  • All 123 patients with negative scans passed nonoperative management
  • Median hospital length of stay was 3 with a range of 2-6 days

Since all of their patients who failed observation did so within 24 hours, the authors recommended a 24 hour observation period for all patients with stabs to the abdomen who did not meet their exclusion criteria.

Bottom line: Trauma professionals have needed a study like this for decades. Until now, we’ve been flying by the seat of our pants, with each surgeon making up his or her own magic number. This is a well done first attempt at defining what that number should be. 

Yes, there are some limitations to the study. The most important one that we don’t know the answer to is how many patients were successfully discharged that presented to another hospital with complications or failure. But this study provides a very reasonable estimate that helps us balance the cost (and patient inconvenience) of time in the hospital vs the dangers of a delayed diagnosis.

The only thing that remains is to design the practice guideline that incorporates the observation period, how often serial exams and labs should be obtained, and when the CT should be repeated.

Reference: Prospective evaluation of the selective nonoperative management of abdominal stab wounds: When is it safe to discharge? Journal of Trauma and Acute Care Surgery: November 2022 – Volume 93 – Issue 5 – p 639-643.

In The Next Trauma MedEd Newsletter: The “Best Of” Issue

The October issue of the Trauma MedEd newsletter will be sent out soon! It is a compilation of my most read and most requested posts.

This issue is being released to subscribers tonight with the Halloween crowd. If you sign up any time before then, you will receive it, too. Otherwise, you’ll have to wait until it goes out to the general public at the end of next week. Click this link right away to sign up now and/or download back issues.

In this issue, get some tips on:

  • How Quickly Does Hemoglobin Drop?
  • How To Remember The “Classes of Hemorrhage”
  • How To: The Serial Abdominal Exam
  • Bathing/Showering And Wound Care

As always, this month’s issue will go to all of my subscribers first. If you are not yet one of them, click this link right away to sign up now and/or download back issues.

Nonsurgical Admissions And The Nelson Score

All trauma centers admit some of their patients to nonsurgical services. This usually occurs when patients have medical comorbidities that overshadow their injuries. Unfortunately, the decision-making that goes into balancing the medical versus trauma issues is not always straightforward. The fear is that if trauma patients are inappropriately placed on a nonsurgical service, mortality and morbidity may be higher because their injuries may not receive adequate attention.

To take some of the variability out of the decision-making process for admitting service, two surgical groups on Long Island created a scoring system that incorporated several parameters described in the ACS Optimal Resource Document (Orange book). Some additional parameters were also included that the authors believed were relevant to the choice of admitting service. Here’s the final list:

The first author on the paper was a nurse, Laura Nelson, and hence this has come to be known as the Nelson Score. Patients with a score score of 7 were considered definitely appropriate for nonsurgical admission. Scores of 4 or 5 were subject to more in-depth review, and those with a score of 3 or less were considered definitely appropriate for trauma service admission. There is no mention of what to do with a score of 6 in the original paper, but I presume it should be almost a slam dunk for considering nonsurgical admission.

The authors evaluated this system’s utility over a two year period. They found that using it placed more patients on the trauma service (nonsurgical admissions decreased from a peak of 28% to somewhere around 10%). They also examined morbidity and mortality statistics between the two types of admissions, and found no significant differences.

The concept was further tested by the trauma group at UCHealth in Colorado Springs. They performed a retrospective review of four years of data that included over 2,000 patients. Patients were older (mean 79 years) and nearly all had blunt mechanism. Mean ISS was 9 and the nonsurgical admission rate was 19%. Patients with a Nelson score of 6 or 7 were even older and had more comorbidities.

Regression analysis did not identify admitting service as a predictor of mortality. The authors concluded that using this score is a safe way to objectively identify patients who would benefit from nonsurgical admission.

Bottom line: I have visited a number of hospitals that successfully use the Nelson score to assist with admission service decision-making while the patient is still in the emergency department. The only gray zone is the score of 4 or 5. Each program will need to determine their own cut point so they can make the service decision more objectively.

Trauma programs can also use this tool to expedite PI review of patients who have already been admitted to a nonsurgical service to check appropriateness. If the score is less than 6 further scrutiny is needed to determine if a consult from or transfer to trauma should be recommended.

References:

  1. Nonsurgical Admissions With Traumatic Injury: Medical Patients Are Trauma Patients Too. Journal of Trauma Nursing, 25 (3), 192-195, 2018.
  2. Evaluation of the Nelson criteria as an indicator for nonsurgical admission in trauma patients. Am Surg, 88(7), 1537-1540, 2022.

How To Remember Those “Classes of Hemorrhage”

The Advanced Trauma Life Support course lists “classes of hemorrhage”, and various other sources list a similar classification for shock. I’ve not been able to pinpoint where these concepts came from, exactly. But I am sure of one thing: you will be tested on it at some point in your lifetime.

Here’s the table used by the ATLS course:

classes_of_shock

The question you will always be asked is:

What class of hemorrhage (or what % of blood volume loss) is the first to demonstrate systolic hypotension?

This is important because prehospital providers and those in the ED typically rely on systolic blood pressure to figure out if their patient is in trouble.

The answer is Class III, or 30-40%. But how do you remember the damn percentages?

multiscore-maxi1

It’s easy! The numbers are all tennis scores. Here’s how to remember them:

Class I up to 15% Love – 15
Class II 15-30% 15 – 30
Class III 30-40 30 – 40
Class IV >40% Game (almost) over!

Bottom line: Never miss that question again!

The Rise And Fall Of MAST Trousers

Remember MAST Trousers (Military Anti-Shock Trousers)? They were a staple of prehospital care starting in the 1970s and lasting through the turn of the century. But what happened after that? They seem to have disappeared. I recently received a question on the topic recently and wanted to share the real story with you readers.

The basic MAST trouser consists of three inflatable compartments: two legs and one covering the abdomen and pelvis. Each can be inflated or deflated separately. The basic concept was first described by a surgeon who wanted to increase blood pressure during neurosurgical procedures in the early 1900s. The US military embraced the concept during the Vietnam war, using it to augment systolic pressure in servicemen in shock.

Military surgeons migrated this device into civilian prehospital care during the mid-1970s, and the American College of Surgeons Committee on Trauma listed this device as essential on all ambulances in 1977. MAST trousers then came into widespread use throughout the 1980s and 1990s.

Early research in the 1970s suggested that this device could provide up to a 20% boost in volume to the upper part of the body when applied. But as occurs with so many new toys, additional research demonstrated that this auto-transfusion effect was actually only about 5% of blood volume. Some significant complications also came to light as lower extremity ischemia and compartment syndromes were described. Ben Taub Hospital published a study in 1987 which showed no improvement in mortality in patients with penetrating injury.

At the end of the century, support for MAST started to dry up. The NAEMSP published a position paper limiting use to ruptured abdominal aortic aneurysms and pelvic fractures with hypotension. The final straw was a review by the Cochrane Collaboration in 2000 that confirmed no reduction in mortality with MAST use.

Although a few older textbooks may still mention MAST trousers, they are no longer the standard of care. There are no longer any accepted indications for their use, and the few trousers that remain are gathering cobwebs in some corner of the trauma basement.

Reference: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan.

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