52 Articles

52 Articles: Head CT in Minor Trauma

This is part of a recurring series examining landmark articles in Emergency Medicine, in the style of ALiEM’s 52 Articles.

Discussing:

Haydel et al., NEJM 2000.  Indications for Computed Tomography in Patients with Minor Head Injury.

Main Points:

1. This two-phase prospective trial sought to “derive and validate a set of clinical criteria that could be used to identify patients with minor head trauma in whom a head CT (HCT) could be foregone.”

2. “Minor head trauma” was defined as: loss of consciousness in a patient presenting with GCS 15, intact cranial nerves, and normal strength and sensation in all extremities.

3.  The presence of at least one of the following: Headache, vomiting, age >60 years old, drug/alcohol intoxication, short-term memory deficit, evidence of trauma above the clavicles, or post-traumatic seizure, was found to be 100% sensitive for subsequently positive HCT (presence of cerebral contusion, subdural or epidural hematoma, depressed skull fracture, or subarachnoid or intraparenchymal hemorrhage).

Background:

Since the advent of CT in the 1970s, many studies have sought to determine the most efficient and best use of this powerful tool for minor head trauma.  Early studies of HCT on patients with GCS 13-15 showed 17-20% incidence of positive findings and recommended HCT for all, but subsequent studies have shown positive HCT findings in GCS 15 patients to be as low as 6-9%.  Historically in the USA, ~66% of annual head trauma is “minor,” ~10% of this group will have positive HCTs, and ~1% will require neurosurgery.  This begs the question: is there a subset of minor head trauma patients for whom HCT adds little or no value?  Could we save time, money, and risk of complications for all participants if we could identify these patients based on clinical presentation? 

Method:

The study occurred at a large urban Level 1 trauma center from 1997 to 1999, and was split into two phases.  Phase 1 enrolled 520 consecutive patients with minor head trauma who were over 3 years old, presenting <24 hours since the trauma, getting a HCT already, and had “minor head trauma,” defined as a loss of consciousness in a patient with a GCS of 15, normal cranial nerves, and normal strength and sensation in all extremities.  No patients who did not lose consciousness or who declined HCT were included, and the CT scan was considered “positive” if it showed a cerebral contusion, subdural or epidural hematoma, subarachnoid, depressed skull fracture, or intraparenchymal hemorrhage.

Seven clinical variables from Phase 1 were found to correlate with positive HCT findings, and their predictive value was prospectively assessed in Phase 2, which enrolled 909 patients with the same inclusion criteria as Phase 1.  Importantly, the Phase 2 patients still received normal trauma care, with HCTs ordered at the discretion of the providers whether or not any of the Phase 1 variables were present; the researchers were simply validating the Phase 1 criteria again.

Results:

●        Phase 1 (520 patients)

○        36 patients (6.9%) had positive HCTs

○        Predictive Variables: Headache, vomiting, age >60, post-traumatic seizure, short-term memory deficit, drug/alcohol intoxication, and evidence of trauma above the clavicles. Of note, "short-term memory deficit + drug/alcohol intoxication + evidence of trauma above the clavicles” were the strongest predictors: If they had scanned ONLY the patients who had all 3 of these combined, the number of scans would have decreased 31%, and sensitivity would still have been 94%

●        Phase 2 (909 patients)

○        57 patients (6.3%) had positive HCTs

○        All patients with positive findings had at least 1 of the seven Phase 1 variables (sensitivity 100% [95% CI 95-100], specificity 25%, NPV 100%)

○        All 212 patients (23.3%) with ZERO Phase 1 variables had negative HCTs (20-26%, 95% CI; NPV 100%)

●        Of 93 patients from both Phases who had positive HCTs (total % → % obs, % surgery):

○        Cerebral Contusion: 47% →  100%, 0% 

○        SDH: 38% → 94%, 6%

○        SAH: 14% → 100%, 0%

○        Epidural: 10% → 78%, 22%

○        Depressed Skull Fracture: 11% → 80%, 20%

Discussion:

●        Historically, lots of head trauma (66%) is minor, with few (~10%) of these patients having positive HCTs, and even fewer (~1%) requiring neurosurgery.  So there is fat to trim.

●        In this study alone, if the criteria derived in Phase 1 had been applied to the Phase 2 patients (ie, “do not scan if zero variables are present”), the number of HCTs would have decreased by 22% with no additional missed findings. This certainly has broader implications when considering the trajectory of our healthcare spending as a percentage of GDP…. which is essentially like the SpaceX Falcon 9 rocket, which has 9 liquid oxygen engines and can generate 1.5 million pounds of thrust at sea level.

○        The study quotes one estimate that a 10% reduction in the number of HCTs in minor head trauma patients would save >$20,000,000 per year

●        This was the first study to derive predictors that were 100% sensitive for positive HCTs, but it is important to note a few caveats:

○        The 95% Confidence Interval of “95-100%” for the sensitivity of their variables indicates that when generalized to the great big world, there is a chance that these predictors will no longer be perfect

○        “Positive CT findings” obviously does not necessarily equate with morbidity or mortality.  Whether we should try to find CT findings or those lesions that require intervention is a broader, and more controversial, topic.  This study simply sought to attain 100% sensitivity for HCT findings with a high degree of confidence.  They provide no information on the clinical significance of these findings as far as mortality or functional outcome.

●        Bottom line: Holding the clinical significance of lesions and a discussion on the sensitivity of HCT aside, discharging patients home after minor head trauma with a negative HCT and a normal neurological exam is generally supported in the literature.  If the variables these investigators are promoting help to identify patients who are exceedingly unlikely to benefit from receiving a HCT, and it saves everyone money, time and some risk of complications, then let’s consider it the next time someone comes in after being struck in the face by a feather.

Level of Evidence:

Based on the ACEP grading system for therapeutic questions this study was graded a level I.

Reviewers:

Resident Reviewer: Dr. Anatoly Kazakin
Faculty Reviewer: Dr. Matt Siket

Source Article:

Haydel et al. Indications for Computed Tomography in Patients with Minor Head Injury. N Engl J Med.  2000 July;343(2);100-105.

52 Articles: Early Goal Directed Therapy in Sepsis

Main Points:

  • In comparison to standard care, early goal-directed therapy (EGDT) was demonstrated to significantly reduce in-hospital mortality for patients presenting with severe sepsis or septic shock.
  • Patients in the EGDT group also demonstrated higher mean SCVO2, a lower lactate concentration, a lower base deficit, and a higher pH when compared to the standard therapy group, suggesting aggressive optimization of hemodynamic parameters and targeting of predefined resuscitation endpoints contributed to their better outcomes. 
  • New multicenter studies have now called into question the value of EGDT as compared to current standard care.   

Background:

Severe sepsis and septic shock are common and have been recognized as a substantial cause of morbidity and mortality in the United States.

Goal-directed therapy, i.e. guiding resuscitation by predefined endpoints based upon laboratory data and invasive hemodynamic monitoring, has long been used and validated in the ICU setting. In this landmark 2001 trial, Dr. Rivers, a physician triple-boarded in emergency medicine, internal medicine and critical care, sought to examine the utility of implementing goal-directed therapy in the emergency department setting for the treatment of severe sepsis and septic shock. Hence, this was “early” goal-directed therapy as opposed to waiting to initiate such treatment in the ICU. More broadly, Rivers’ thought process mirrored the rising trend of “bringing upstairs care downstairs” and the continuing evolution of critical care in emergency medicine.

For Rivers, sepsis was a particularly salient target of early goal-directed therapy, as it was a disease state that could be altered through timely intervention, with pathology that was largely driven by changes in hemodynamics. According to this school of thought, sepsis spans a pathophysiologic continuum that begins with the systemic inflammatory response syndrome and, if left untreated, progresses to end organ failure and death. The circulatory abnormalities that result from sepsis, namely intravascular volume depletion, peripheral vasodilation, myocardial depression and increased metabolism, create an imbalance between oxygen delivery and oxygen demand throughout the body. It is this imbalance that chiefly drives and is responsible for global tissue hypoxia, shock, and death. Rivers thought that progression along this continuum of disease could be halted by early recognition and correction of the systemic imbalance between oxygen delivery and demand. To that end, promptly optimizing hemodynamics by meeting specific resuscitation end points or “goals,” could reduce the morbidity and mortality of sepsis.

Details:

This was a prospective, randomized study that enrolled 263 patients who presented to a single urban emergency department over a three-year period with severe sepsis or septic shock. Criteria for inclusion were 2/4 SIRS criteria along with an SBP ≤ 90mm Hg after a 20-30cc/kg bolus of IV crystalloid OR a blood lactate concentration of ≥ 4mmol/L. Exclusion criteria were numerous and included: age < 18 years old, pregnancy, acute CVA, ACS, acute pulmonary edema, status asthmaticus, cardiac dysrhythmias, GI bleeding, seizure, drug overdose, burn injury, trauma, cancer on chemotherapy, immunosuppression, contraindications to central venous catheterization or DNR status. Patients were randomized by computer assignment to either early goal-directed therapy or to standard therapy. Of note, the treating clinicians in the ED were not and practically speaking could not be blinded to these assignments.

Standard therapy was described in this study as being “at the discretion of the clinician,” and consisted broadly of central venous and arterial catheterization with a goal of maintaining a CVP of 8-12mm Hg, MAP > 65mm Hg, and urine output > 0.5mL/hr. Cultures were obtained and antibiotics administered. Critical care consultation was also obtained and patients were admitted from the ED as soon as possible.  

Conversely, patients in the early goal-directed therapy group were treated by a specific protocol for at least six hours in the ED and then transferred to inpatient beds. The critical care clinicians who subsequently assumed care of these patients were not aware of their study group assignments. According to the EGDT protocol, 500cc IVF crystalloid boluses were given every 30 minutes to achieve CVP of 8-12 mm Hg. If MAP was < 65, vasopressors were given. If MAP was > 90, vasodilators were given. If central venous oxygen saturation was < 70%, pRBCs were transfused to achieve a hematocrit of at least 30%. If the CVP, MAP and hematocrit were optimized and SCVO2 was still < 70%, dobutamine was started at 2.5mcg/kg/min and increased until SCVO2 was 70% or higher or the maximum dose of dobutamine was given. If the patient was still not hemodynamically optimized after these interventions, they would be mechanically ventilated and sedated if they were not already.

The primary efficacy end point was in-hospital mortality. Secondary end points for resuscitation such as temperature, heart rate, blood pressure, urine output, and CVP were also measured out to 72 hours. APACHE II, SAPS II and MODS scores were further calculated as was consumption of health care resources.

Overall, the study found a significant reduction of in-hospital mortality in the EGDT group as compared to the standard therapy group (30.5% vs. 46.5%, relative risk of 0.58 (0.38-0.87), P = 0.009). With regard to other secondary resuscitation end points, the study authors found that between 7-72 hours, those in the EGDT group had a significantly higher mean central venous oxygen saturation (70.4±10.7 percent vs. 65.3±11.4 percent), a lower lactate concentration (3.0±4.4 vs. 3.9±4.4 mmol/L), a lower base deficit (2.0±6.6 vs. 5.1±6.7 mmol/L), and a higher pH (7.40±0.12 vs. 7.36±0.12) than the patients assigned to standard therapy (P < 0.02 for all comparisons). They also found APACHE II, SAPS II and MODS scores to be significantly higher in patients assigned to standard therapy as opposed to those assigned to EGDT (P= < 0.001), suggesting a greater degree of end organ dysfunction in the standard therapy group as compared to the EGDT group.

There were interesting differences noted in the amount and timing of resuscitation between the two groups. Perhaps unsurprisingly, in the first 6 hours the EGDT group received more IVF (5 vs. 3.5L, p < 0.001), pRBC transfusions (p < 0.001), and inotropic support (p < 0.001). Between 7-72 hours however, the standard care group received more pRBC transfusions (p < 0.001), more vasopressors (p=0.03), more mechanical ventilation (p<0.001) and more PA catheterization (p=0.04). This suggests that the standard therapy group was initially under-resuscitated in the first 6 hours, contributing substantially to longer term morbidity and mortality. 

Where to go from here:

Although fundamentally altering the standard of care for sepsis, Rivers’ study has since come under increasing scrutiny, particularly in light of the recent ARISE and ProCESS trials, two multicenter studies that demonstrated no difference for in-hospital mortality between EGDT and standard therapy (see relevant articles below). These new studies, however, have been questioned given the possibility of significant overlap now between “standard” care and EGDT as a result of Rivers’ work having altered the standard of care itself. While the utility of certain aspects of EGDT, such as following SCVO2 to guide resuscitation, have been questioned, Rivers’ work set the standard for the aggressive treatment of sepsis that we see today. This in turn has resulted in a significant decline in the morbidity and mortality of sepsis over the past several decades.

Level of evidence:

Based on the ACEP therapeutic grading scheme this article is Level I evidence.

Resident Reviewer: Dr. Anatoly Kazakin
Faculty Reviewer: Dr. Matt Siket

Relevant articles:

Peake, S. et al. “Goal-directed resuscitation for patients with early septic shock.” NEJM 371;16 Oct 16, 2014.

Yealy, D. et al. “A randomized trial of protocol-based care for early septic shock.” NEJM 370;18 May 1, 2014. 

52 Articles: Trauma Care: Does it Matter Where You Happen to be Minding Your Own Business?

This is part of a recurring series examining landmark articles in Emergency Medicine, in the style of ALiEM’s 52 Articles

Main Points:

After adjusting for differences in case mix the overall risk of mortality is 25 percent lower at a trauma center than a non-trauma center. The differences in risk of death is greatest for younger patients with higher Abbreviated Injury Scale scores (≥4).

Background:

Since 1976 the American College of Surgeons have advocated categorizing hospitals for care of traumatic injuries based on available resources. This has created a regionalized approach that we see today in management of trauma patients based off trauma level designations for each hospital and is affected substantially by geographic variability between states. The National Study on the Costs and Outcomes of Trauma (NSCOT) was established to address the differences in patient outcomes and costs between various hospitals, primarily trauma versus non-trauma centers. The authors concluded that though the effects of care at a trauma center varied based on severity of injury there was a mortality benefit in the more ill cohort. This study reviewed the outcomes for over 5,000 patients, however, many limitations still exist given the retrospective nature of case review. Management of trauma patients will likely continue to follow a regionalized model for many years to come given the intensive needs of some patients compared to others. As emergency physicians our role will continue requiring us to provide exceptional care from the moment the patient arrives in our resuscitation bay and acknowledging the elements that require emergent transfer to a hospital that can provide further specialized care.

Details:

This was a large case registry trial that examined patient data from across 14 states. 18 level-1 trauma centers and 51 non-trauma centers were included in the data collected. Data was gathered on 1104 patients who died in the hospital and 4087 who were discharged.  The study was based on trauma centers in urban and suburban America and conclusions therefore cannot be extrapolated to more rural areas. On average non trauma centers were smaller and less likely to be members of the Council of Teaching Hospitals. The included non-trauma centers, however, were required to see a minimum of 25 patients with major trauma annually to be enrolled. Out of 131 non trauma centers asked to participate 51 agreed, but many cited a lack of administrate support to facilitate the study and therefore refused and 7 were refused by their IRB.

Patients aged 18-84 were eligible if they were treated for moderate to severe injuries as defined by the AIS>3. Interesting exclusions included those patients aged 65 or greater whose primary diagnosis included hip fracture. Patients with major burns were also excluded. Enrollment proceeded through a flow pathway that narrowed the pool from over 18,000 to 4,000 based on missing data in the chart review. The primary outcome was mortality in the hospital as well as death at 30, 90, and 365 days after injury. Patients were evaluated using the Charlson comorbidity index to balance the study arms and factors such as obesity and coagulopathy were added to the data collection models since these variables have a large impact on outcomes in traumatic injuries.

Patients treated in non-trauma centers tended to be older and unsurprisingly had more coexisting conditions. They also represented a larger portion of female, non-Hispanic white, and insured patients with overall less severe injuries. The unadjusted case fatality rate was higher at trauma centers, 8 v. 5.9%, however when adjusting for case mix, the risk of death at one year was significantly lower when care was provided at a trauma center compared to non-trauma center, 10.4 v 13.8%. The relative reduction in risk was similar for in-hospital, 30 and 90-day mortality. The data seemed to show a critical point at an AIS≥4 and age of 55.

One of the major limitations the authors cite in reviewing their data is that there is no perfect method to adjust for referral bias—largely “…the reality [is] that trauma centers treat a higher proportion of young, severely injured patients, whereas non-trauma centers treat a higher proportion of elderly patients with coexisting conditions.” Ultimately the authors arrived at a conclusion of benefit for the patients more severely injured and <55 years old when their care was performed at a trauma center. No trials will ever definitively prove this benefit through randomization and we will most likely see little change in our regional model of trauma care. Going forward, however, we may utilize points gathered in this large review to help aid us with clinical decisions about when to transfer patients to higher levels of care.

Level of Evidence:

Based on ACEP grading of level of evidence for prognostic questions this case registry is graded a level III.

Source Articles:

Mackenzie, E. Rivara, F. Jurkovich, G. et al. “A National Evaluation of the Effect of Trauma-Center Care on Mortality.” NEJM, 2006:354(3). 366-78.

Faculty Reviewer: Dr. Matt Siket