Atrial Fibrillation, You’re a Heart Breaker, Dream Maker, Love Taker:

But At Least There is Low Risk for Thromboembolic Events With Speedy Conversion to Sinus Rhythm…

This post reviews the article from Weigner, Marilyn et al. “Risk for Clinical Thromboembolism Associated with Conversion to Sinus Rhythm in Patients with Atrial Fibrillation Lasting Less Than 48 Hours,” from the Annals of Internal Medicine in 1997 as part of the ongoing 52 article series.

Main Points:

  1. This article reveals only a 0.8% risk of clinical thromboembolic event for patients who were clinically estimated to be in atrial fibrillation for less than 48 hours.
  1. This trial data supports the recommendation for early cardioversion, either pharmacologic or through electric cardioversion, in patients with recent onset of symptoms without the need for prior diagnostic imaging to evaluate for clot burden.

Background:

Atrial fibrillation is a common arrhythmia and responsible for over 250,000 hospital admissions annually. Patients often feel the effects of depressed cardiac output from the loss of atrial systole and seek medical attention in hopes of improved quality of life. Patients may describe a range of symptoms including palpitations, dyspnea, dizziness, angina and fatigue. Studies have demonstrated that patients with atrial fibrillation for more than two days may have a greater than five percent risk of clinical thromboembolism and often require weeks of anticoagulation or screening with transesophageal echocardiography prior to cardioversion. This study sought to answer the question of whether or not patients who experienced only a short duration of symptoms were low risk for thromboembolic disease.

Details:

This was a prospective study of consecutive patients at two academic medical centers, Beth Israel Deaconess Medical Center in Boston, MA and the John Dempsey Hospital and University of Connecticut Health Center in Farmington, CT. 1822 adult patients with a diagnosis of atrial fibrillation were screened and 375 patients who were clinically estimated to have symptoms for less than 48 hours were enrolled. Those patients whose duration of symptoms were unclear or had already initiated long term anticoagulation with warfarin were excluded. Patients with a previous history of thromboembolic events were not excluded, but one patient who had an acute thromboembolism was not enrolled in the trial. Clinical and transthoracic echocardiography data and outcomes were collected from review of the medical records. Clinical embolic events were considered if they occurred during the index hospitalization or within one month after conversion to sinus rhythm. Conditions that may have predisposed patients to atrial fibrillation included: previous history of atrial fibrillation (181 patients, 48.3%), hypertension (156, 41.7%), coronary artery disease (114, 30.4%), infection (25, 6.7%), history of thromboembolism (23, 6.1%), excessive alcohol use (22, 5.9%), rheumatic heart disease (7, 1.9%). Patients were noted to have left atrial dimensions of 4.2 +/- 0.7cm (normal ≤ 4.0cm) and a left atrial length of 5.7 +/- 0.7cm (normal ≤ 5.2cm) based on transthoracic echocardiogram data. 218 out of 280 patients who had echocardiograms performed were noted to have at least some evidence of mitral valve regurgitation with 61 patients noted to have either moderate or severe regurgitation.

Patients converted back to a normal sinus rhythm either spontaneously or through pharmacologic or electric cardioversion methods. Conversion was considered spontaneous if it occurred without the use of medications or electricity or in the setting of use of ventricular rate-controlling agents (digoxin, beta-blockers, and calcium channel blockers).

Three patients (0.8%, 95% CI 0.2-2.4) were noted to have a clinically significant thromboembolism and surprisingly all converted spontaneously. The cases included a left parietal embolic stroked in an 86 year old female with history of hypertension; a right proximal brachial artery embolus in an 83 year old female with coronary artery disease; and a transient ischemic attack in an 89 year old female with a recent diagnosis of pneumonia.

This study was a consecutive series that relied on both real time data gathering as well as retrospective chart review.

Level of Evidence:

This study was graded a level II based on the ACEP Clinical Policy Grading Scheme for prognostic questions and had only minimal methodological flaws.

Surprises:

The three patients in this trial were identified as having increased risk for thromboembolism based of the Stroke Prevention and Atrial Fibrillation Study I and II, however, how best to achieve post conversion anticoagulation in the era of direct oral anticoagulants remains a hot topic for further study and debate.

Relevant articles:

Mookadam, M. Shamoun FE. Mookadam, F. “Novel Anticoagulants in Atrial Fibrillation: A Primer for the Primary Physician.” J Am Board Fam Med, 2015, 28(4):510-22

Source Articles:

Weigner, M. Caulfield, T. Danias, P. et al. “Risk for Clinical Thromboembolism Associated with Conversion to Sinus Rhythm in Patients with Atrial Fibrillation Lasting Less Than 48 Hours.” Annals of Internal Medicine, 1997, (126):615-20.

Faculty Reviewer: Dr. Siket

Spare the Tube, Save a Life

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

Discussing:

Brochard, L. Mancebo, J. Wtsocki, M. et al. “Noninvasive Ventilation for Acute Exacerbations of Chronic Obstructive Pulmonary Disease.” NEJM 1995, 333(13):817-22.

Main Points:

  1. In this randomized prospective multicenter trial of 85 patients admitted to ICUs throughout Europe with COPD exacerbations, noninvasive ventilation reduced the need for endotracheal intubation, length of stay and in-hospital mortality rate.
  1. 31 of the 42 patients in the standard arm required intubation, compared to 11 of 43 patients in the noninvasive arm (p<0.001). These results were consistent among the five centers studied. The mortality rate and length of stay was similar in the two groups in whom endotracheal intubation was required, suggesting that the benefits observed in noninvasive ventilation resulted from lower rates of intubation.
Figure 1. Mask used to deliver noninvasive ventilation

Figure 1. Mask used to deliver noninvasive ventilation

Background:

COPD exacerbations often manifest as acute hypercapnic ventilatory failure and endotracheal intubation can be a life-saving procedure. This intervention, however, is not without associated risks both during the time of the procedure as well as later in the course of the patient’s care. This patient population is at risk for hemodynamic compromise during intubation and may be difficult to manage on the ventilator due to a multitude of concerns including air trapping and tachypnea. The risk for ventilator associated pneumonia and other complications secondary to being intubated for prolonged periods of time are also worth considering.

Brochard and his colleagues investigated the use of noninvasive ventilation in COPD exacerbations in hopes of reducing mortality through the reduction of intubation. Thiswas a multicenter prospective randomized study that recruited patients in five European ICUs. The primary and secondary outcomes were patient-centered and this article from 1995 has clearly framed the manner in which we manage the sick COPD patient today. The medications used and manner in which noninvasive ventilation is employed has evolved since the publication and a comprehensive review of management was published in 2010 by the American Academy of Family Physicians. ACEP also has published clinical guidelines on use of noninvasive ventilation in 2010.

Details:

This prospective multicenter study enrolled 85 out of 275 patients admitted to the ICU with COPD or a high probability of the disease based on careful history, physical examination and chest x-ray. Patients were selected if they had a respiratory acidosis and elevated bicarbonate level. Additional criteria included dyspnea for less than two weeks and at least two of the following: respiratory rate >30 BPM, partial pressure of arterial O2 <45 mm Hg, arterial pH <7.35 after the patient was breathing room air for at least 10 minutes. The exclusion criteria included: respiratory rate <12 BPM, need for immediate intubation-defined by strict criteria in the paper, already intubated, use of sedative drugs in the past 12 hours, CNS disorder, cardiac arrest in the past five days, cardiogenic pulmonary edema, neuromuscular or skeletal disorder, upper airway obstruction or asthma, clear cause of decompensation requiring treatment, or facial deformity. Patients were either assigned to the standard arm which included treatment with: maximum of 5LPM O2 by nasal prongs with goal O2 saturation >90%, medications such as subcutaneous heparin, antibiotic agents and bronchodilators (subcutaneous terbutaline, aerosolized or intravenous albuterol, corticosteroids or intravenous aminophylline), correction of electrolytes. The noninvasive arm received the same medications with the addition of periods of noninvasive ventilation. The same apparatus was used at all five sites to deliver pressure support of 20 cm H20 with an expiratory pressure that was atmospheric. Patients underwent noninvasive ventilation for at least six hours a day with overall duration determined by clinical criteria and arterial blood gal levels.

In order to standardize care, the authors created major and minor criteria as objective markers for the need to perform endotracheal intubation. The major criteria included: respiratory arrest, respiratory failure with LOC or gasping for air, psychomotor agitation making nursing care impossible and requiring sedation, HR<50 BPM with loss of alertness, hemodynamic instability with SBP <70 mm Hg. There was a series of minor criteria also relating to vital sign instability, mental status changes or arterial pH <7.3. In both groups the presence of one major criterion was an indication for intubation. After the first hour of treatment the presence of two minor criteria was an indication for intubation.

Patients were evaluated at the one hour, three hour and 12 hour mark following the initiation of therapy. The primary outcome examined was the need for endotracheal intubation with secondary end points including length of stay, complications not present on admission (pneumonia, barotrauma, gastrointestinal hemorrhage, renal insufficiency, neurologic events and pulmonary embolism), duration of ventilatory assistance, and mortality rate during hospitalization. 31 of the 42 patients in the standard arm required intubation, compared to 11 of 43 patients in the noninvasive arm (p<0.001). Per the authors, these results were consistent among the five centers studied, however, examining table 2 sites one and two seemed to have high percentages of intubation, 100 and 83 percent respectively, compared to the others. This may be skewed by the overall low numbers studied. Patients who ultimately were intubated both in the standard and noninvasive arms had extended ventilation time with 17 +/- 21 days and 25 +/- 17 days respectively. Complications and events leading to death are shown in Table 4.

Level of Evidence:

This study was graded a level I based on the ACEP Clinical Policy Grading Scheme for therapeutic questions.

Surprises:

The use of pressure support of 20/0 is quite different from the manner in which many providers initiate noninvasive ventilation today. This may be secondary to the limitations of the technology at the time because the photograph in figure 1 (see above) displays a mask that appears different from what you find on modern machines.

Relevant articles:

Ahn, J. Pillow, T. “Focus On: Noninvasive Positive Pressure Ventilation in the Emergency Department.” 2010, http://www.acep.org/Clinical—Practice-Management/Focus-On–Noninvasive-Positive-Pressure-Ventilation-In-the-Emergency-Department/

Evensen, A. “Management of COPD Exacerbation.” Am Fam Physician 2010, 81(5): 607-13. http://www.aafp.org/afp/2010/0301/p607.html

Faculty Reviewer: Dr. Siket

Source Articles:

Brochard, L. Mancebo, J. Wtsocki, M. et al. “Noninvasive Ventilation for Acute Exacerbations of Chronic Obstructive Pulmonary Disease.” NEJM 1995, 333(13):817-22.

Hit Them Hard: The Use of H1 and H2 Antagonists for Acute Allergic Symptoms

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

This blog post reviews the article by Lin, R. Curry, A. Pesola, G. et al. “Improved Outcomes in Patients With Acute Allergic Syndromes Who Are Treated With Combined H1 and H2 Antagonists.” Annals of Emergency Medicine, November 2000; 36(5):462-8.

Main Points:

  1. In this randomized, double blinded, placebo controlled trial of 91 patients presenting with acute allergic symptoms fewer patients in the active arm (ranitidine + diphenhydramine) had signs of cutaneous involvement such as urticaria at 2 hours compared to the placebo group (placebo + diphenhydramine).
  1. There was no significant difference, however, between the placebo group and active group with regards to the absence of erythema or angioedema at two hours.

Background:

Many patients present to the emergency department with acute allergic syndromes. Anti-histamines, primarily diphenhydramine, are the mainstay therapy in most mild cases and are both safe and cost effective. The addition of H2 antagonists such as ranitidine to diphenhydramine may help improve clinical outcomes and expedite management in the emergency department. The primary goals of this study were to look for resolution of urticaria and angioedema at two hours from presentation. This study was well balanced in its patient recruitment and overall provides insight into real-world application of a second agent for management of allergic symptoms.

Details:

The methodology within this study was rigorous, though the sample size was small. This trial was a randomized, double blinded, placebo controlled trial that enrolled 91 patients at an academic emergency department in New York, NY. Enrollment was based on a convenience sampling associated with the study physicians’ scheduling. Patients were enrolled in this study if they were adults who presented with acute urticaria, acute angioedema, acute unexplained stridor or acute pruritic rash following an exposure to a food, drug or contact with latex. Patients underwent vital sign monitoring, examination for physical findings such as: presence and extent of urticaria and erythema, presence of angioedema, wheezing, stridor, abdominal distention or tenderness, as well as symptom scoring. This data collection occurred at presentation, at 1 hour and 2 hours.

This study demonstrated a statistically significant difference, p=0.03, in the resolution of urticaria in the active group compared to the placebo group at two hours. One significant limitation in this study is that the treating physician was able to administer supplemental medications such as epinephrine, corticosteroids, bronchodilators and additional doses of antihistamine at their discretion with significantly more participants in the ranitidine arm receiving epinephrine, 17, compared to 9 in the placebo arm. The placebo arm had more use of additional antihistamine, 10, compared to 2 in the ranitidine arm. These additional therapies are documented in table 3; however, it is unclear if the severity of illness was equal between the two groups. The authors do note in their discussion that there was no observed covariate effect for epinephrine administration with respect to urticaria resolution.

Level of Evidence:

This study was graded a level I based on the ACEP Clinical Policy Grading Scheme

Surprises:

Within the sample groups there was significant history of asthma as well as other nonasthmatic atopic conditions which supports the theory that certain individuals are genetically predisposed to allergic syndromes.

Source Articles:

Lin, R. Curry, A. Pesola, G. et al. “Improved Outcomes in Patients With Acute Allergic Syndromes Who Are Treated With Combined H1 and H2 Antagonists.” Annals of Emergency Medicine, November 2000; 36(5):462-8.

Faculty Reviewer: Dr. Siket

You Put a Catheter Where? The Groin May Not be as Dirty as Previously Reported

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

Discussing:  Marik, P. Flemmer, M. Harrison, W. “The Risk of Cathether-Related Bloodstream Infections with Femoral Venous Catheters As Compared to Subclavian and Internal Jugular Venous Cathethers: A Systematic Review of the Literature and Meta-Analysis.” Critical Care Medicine, 2012, Vol 40(8). 2479-2485

Main Points:

  1. This 2012 meta-analysis demonstrated that catheter-related blood stream infection (CRBI) risk is no different between internal jugular, subclavian, and femoral catheter insertion. The authors demonstrated that previous level 1A guidelines regarding femoral catheter infectious risk were in error.
  2. The overall risk of CRBI is declining over the recent years and likely due to the combination of more precautions at the time of insertion as well as vigilant management of the catheter once placed.

Background:

There is significant morbidity and mortality associated with CRBI. In the United States alone, an estimated 30-60 thousand patient deaths occur annually secondary to this infectious process. In 2011 a clinical recommendation from respected organizations including the CDC’s Healthcare Infection Control Practices Advisory Committee as well as the Infectious Disease Society of America issued a class 1A recommendation to “avoid using the femoral vein for central access in adult patients.” This recommendation would suggest that there is strong supporting data including at least one well performed RCT. The purpose of this meta-analysis by Marik and his colleagues was to call into question the validity of such an absolute statement. Marik and his partner Flemmer performed an exhaustive literature search and were able to find 2 RCTs and 8 cohort trials to include in their meta-analysis. This literature review was more comprehensive then the citations provided by the societies issuing the level 1A recommendations. There study, however, focused solely on the question of CRBI and did not address concerns other concerns associated with central venous access such as injury to nearby structures, DVT, or bleeding.

Details:

This study reviewed more data than the 1A recommendation from the CDC and IDSA and could not find compelling evidence that the femoral vein should be avoided for concerns of CRBI. Furthermore, it appears that the universal precautions that are being used currently have likely led to an overall decrease in CRBI compared to the years past. For example, the rate of CRBI in the United States in 1998 was 5.32/1,000 catheter days and has subsequently dropped to 2.05/1,000 in recent data. The Welsh Healthcare Associated Infection Program which is the largest collection of data and noted that in over 55 thousand catheter days in 2009 and 2010 there were only 0.61/1,000 catheter day infectious risk with no difference between insertion sites. Marik and his colleagues therefore note that the site of preference should “depend on the expertise and skill of the operator and the risks associated with placement.” The authors recommend against using femoral vein catheters in renal transplant patients, patients who would benefit from early mobilization as well as the massively obese due to a subgroup analysis in the Parienti study that noted worse outcomes in these individuals.

The average CRBI density in the compilation of trials was noted to be 2.5 +/- 1.9 per 1,000 catheter days (range 0.6-7.2). In compiling the data it was noted that two of the cohort trials, Lorente and Nagashima, appeared as statistical outliers increasing the heterogeneity of the meta-analysis significantly. It is unclear why these two trials demonstrated a more than two-fold increased risk of CRBI with femoral catheter insertion. If these trials were removed from the data the authors noted that there appeared to be no heterogeneity within the study (RR 1.02, 95% CI 0.64-1.65, p = 0.92, I² = 0%). This study also performed a meta-regression that appeared to demonstrate a significant interaction between the risk of infection and the year of publication (p = 0.01).

Level of Evidence:

Based on the design of this study, including RCTs and cohort trials, with a few limitations this study was graded a level III based on the ACEP Clinical Policy Grading Scheme for meta-analyses.

Surprises:

In many aspects of medicine it is curious to see how wide practice variation can be, especially when considering geographic and healthcare system influences. This notion is highlighted by reviewing the different guidelines within this meta analysis by various public health/safety committees across the United States and United Kingdom.

Relevant articles:

Lorente, L. Henry, C. Martin, MM. et al. “Central Venous Catheter-Related Infection in a Prospective and Observational Study of 2, 595 Catheters.” Crit Care, 2005 9. R631-5

Nagashima, G. Kikuchi, T. Tsuyuzaki, H. et al. “To Reduce Catheter-Related Bloodstream Infections: Is the Subclavian Route Better than the Jugular Route for Central Venous Catheterization?” J Infec Chemother, 2006 12. 363-65

Parienti, JJ. Thirion, M. Megarbane, B. et al. “Members of the Cathedia Study Group: Femoral v. Jugular Venous Catheterization and Risk of Nosocomial Events in Adults Requiring Acute Renal Replacement Therapy: A Randomized Controlled Trial.” JAMA, 2008 299. 2413-22

Source Articles:

Marik, P. Flemmer, M. Harrison, W. “The Risk of Cathether-Related Bloodstream Infections with Femoral Venous Catheters As Compared to Subclavian and Internal Jugular Venous Cathethers: A Systematic Review of the Literature and Meta-Analysis.” Critical Care Medicine, 2012 Vol 40(8). 2479-2485

By

Anatoly Kazakin MD

‘Let’s talk about N-STEMI, Let’s talk about Cath, baby, Let’s talk about all the good things and the bad things that may be…’

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

Discussing: Mehta et al., NEJM 2005. Routine vs. Selective Invasive Strategies in Patients With Acute Coronary Syndromes. A Collaborative Meta-analysis of Randomized Trials PMID: 15956636

Main Points:

  1. This 2005 meta-analysis was devised to answer one of medicine’s most stubborn (but important) questions: Is an ‘early invasive’ strategy for Unstable Angina (UA) and Non-ST-Elevation Myocardial Ischemia (NSTEMI) associated with improved outcomes compared to medical therapy alone?
  2. Yes and no! High-risk patients with positive biomarkers and evidence of ongoing ischemia seem to gain long-term benefit from immediate coronary angiography and revascularization. This benefit appears to outweigh the increased hazard associated with a routine invasive strategy.
  3. Patients with negative biomarkers and lower risk don’t appear to gain long-term benefit from invasive strategy and therefore the increased hazard of a routine invasive strategy is not justified in this group. Patients with negative biomarkers do just as well with medical therapy alone.

 

Background:

 

Acute Coronary Syndrome (ACS) comprises a spectrum of illness. Presenting signs, symptoms and clinical findings (elevated troponin, EKG changes) are thought to correlate with the degree and the acuity of ischemia. In theory, patients with more severe illness are thought to benefit from more aggressive therapies – i.e. invasive revascularization – while patients with less severe illness have been thought to derive equal benefit medical therapy alone. To an extent, these suppositions have been proven true: There are clear mortality benefits to emergent PCI for patients with STEMI. However, optimal treatment for patients presenting with unstable angina or NSTEMI remains controversial. Importantly, the goal of revascularization in STEMI is different then in NSTEMI/UA. For STEMI, PCI is intended to restore perfusion by eliminating an occlusive thrombus. In NSTEMI, thrombi typically are not occlusive – thus the focus of PCI is to improve long-term outcomes.

 

The purpose of this study was to determine whether a routine invasive strategy vs. a selective invasive strategy was more effective in the treatment of ACS. The authors devised a meta-analysis of randomized trials to answer this question. Continue reading

Stop Mucking Around and Throw the End Tidal On: A Safer Way to Perform Procedural Sedation and Analgesia!

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

Discussing: “Does End-tidal Carbon Dioxide Monitoring Detect Respiratory Events Prior to Current Sedation Monitoring Practices?” Burton, J. Harrah, J. Germann, C. Et al. Acad Emerg Med, May 2006, 13(5): 500-4

 

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Main Points:

  1. This trial was stopped early after an interim safety analysis demonstrated that standard care was potentially placing patients at higher risk for delayed recognition of acute respiratory events. 17 out of 20 acute respiratory events recorded in the dataset demonstrated changes in the end tidal carbon dioxide (ETCO2) level indicative of hypoventilation or apnea.
  2. Twenty acute respiratory events were recorded in the study cohort of 60 procedural sedation and analgesia (PSA) encounters. In 14 of these episodes, the ETCO2 demonstrated changes prior to SpO2 change or clinically observed hypoventilation.

Background:

PSA is a routine practice that is critical to many tasks in the emergency department. There are many guidelines from various professional societies that discuss the components of PSA and associated requirements for safe patient monitoring. Many clinicians use a wide array of pharmacologic options based on patient characteristics when performing PSA, yet it is always challenging to predict how each individual will respond to the drugs used. Therefore, having an extra tool for patient monitoring that will improve safety is a great aid for quality patient care.

ACEP has issued multiple guidelines over the past decade to keep up with the evolution of clinical practice as well as technologic changes such as capnography. Currently ACEP has a level B recommendation for the use capnography as part of the PSA monitoring tools. The article by Burton and his colleagues is one of many studies that helped change practice patterns over the past ten years. The authors collected a prospective convenience sample of two 30 patient blocks undergoing PSA at a single tertiary ED. There was an attending and 3 residents collecting ETCO2 data during PSA events and the clinical team was blinded to this information. The purpose was to identify the ability of ETCO2 to detect acute respiratory events before conventional strategies. Continue reading

Crack the Chest

Part of our recurring ’52 Articles’ series exploring landmark articles in Emergency Medicine, inspired by the ALiEM blog’s index project, 

Main Points:

  1. Over 23 years 950 patients underwent post injury thoracotomy at Denver Health Medical Center and overall survival was noted to be 4.4 percent with 3.9 percent surviving functionally intact.
  1. Using various assumptions for cost analysis the authors concluded that “the benefit-charge ratio was strongly in favor of performing EDT [emergency department thoracotomy] at 5.6:1, it was 1.8:1 if adjusted for the cost of maintaining all neurologically injured survivors throughout their lifetime.”

Background:

Emergency department thoracotomy remains a hotly debated procedure within the scope of emergency medicine.  Not only is it a resource intense process that potentially places providers at increased risk for blood borne infections, but it is also one whose utility has been questioned given the limited success rate of meaningful patient outcomes. The authors of this study reviewed a cohort of consecutive trauma patients presenting to a level I hospital in Denver, CO in hopes of clarifying not only the costs as well as the utility of the procedure. The authors in this study reported “neurologically intact survival at time of discharge” as one of the study outcomes; however, it does not appear that any patients had post-hospitalization follow up to evaluate for any future changes. Continue reading

Therapeutic Hypothermia: Delightful Brain Freeze

 

Main Points:

  1. This study demonstrates that the number needed to treat with therapeutic hypothermia to prevent one unfavorable neurological outcome is 6. The number needed to treat to prevent a single death is 7.

 

  1. Overall 75 of the 136 patients in the hypothermia group had favorable neurological outcomes as defined by the Pittsburgh cerebral performance grading scale. Only 54 of 137 patients in the control arm had favorable neurological outcomes recorded.Mortality in the hypothermia group at six months was 41 percent compared to 55 percent in the normothermic group.

 

Background:

The exact mechanism for the beneficial effects of therapeutic hypothermia are unclear with regards to favorable neurological outcomes, but it has been postulated that a reduction in cerebral oxygen consumption or a disruption in the inflammatory and acute phase cascade helps to prevent further brain injury following cardiac arrest. At the time of this study over 375,000 people in Europe were being treated annually for cardiac arrest with overall poor neurological outcomes. Continue reading

Canadian Cervical Spine Rules: Moving North a Better Option, Eh?

Main Points:

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1. The final Canadian C-spine Rule comprises three questions:

A.) Is there a high-risk factor that mandates radiography such as: age≥65, dangerous mechanism, or paresthesias in extremities?

B.) Is there any low-risk factor that allows safe assessment of range of motion such as: simple rear end MVC, sitting position in ED, ambulatory at any time since injury, delayed onset of neck pain, or absence of midline C-spine tenderness?

C.) Is the patient able to actively rotate neck 45° to the left and right?

 

  1. The Canadian C-Spine Rule was tested on a convenience sample of 8,924 alert and stable trauma patients in 10 Canadian emergency departments with 151 cases of clinically significant C-spine injury and proved to have a sensitivity of 100% (95% CI: 98-100%) and a specificity of 42.5% (95% CI: 40-44%).

 

Background:

Less than three percent of trauma series yield a positive result.

According to the data compiled by the researchers in the Canadian CT Head and C-Spine Study the use of C-spine radiography is quite variable among emergency physician providers based on local culture and the overall cost of C-spine radiography is in the multi-millions. Their research demonstrated that less than three percent of trauma series yield a positive result. Continue reading

NEXUS Review: Clear That Collar Doc!

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This is the first in a blog series that will explore landmark articles in Emergency Medicine. 

Main Points:

  1. Patients meeting the following five simple clinical criteria are safe to clear without cervical spine imaging following blunt trauma:
    • No focal neurologic deficit
    • Normal alertness
    • No intoxication
    • No midline posterior bony cervical spine tenderness, and
    • No painful distracting injury
  1. The sensitivity and specificity of the NEXUS criteria for detecting low probability injury and avoiding unnecessary imaging was 99 and 12.9 percent respectively, with a negative predictive value of 99.8 percent for the detection of clinically significant injuries.

Level of evidence: 1 (Prospective cohort trial)

Based on the ACEP grading scheme for diagnostic questions the NEXUS trial receives a class of evidence rating of 1.

Background:

Blunt trauma is a frequent cause of emergency department visits. However, the overall prevalence of cervical spine injury is generally only between 2-4% (2.4% in the NEXUS cohort). The goal of the NEXUS group was to create a simple clinical tool with which to risk stratify patients following blunt trauma, thereby reducing unnecessary cervical spine imaging and subsequently improving patient care through cost-reduction and a decrement in the downstream oncogenic risk secondary to radiation exposure. Continue reading