Category Archives: All Updates

Acute Med, All Updates, Resus, Trauma

Modified ED thoracotomy to avoid exsanguination

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Emergency physicians from Minnesota (and graduates of the amazing Hennepin Emergency Medicine Residency) describe a patient who developed cardiac tamponade after an ablation procedure for dysrhythmia. Attempts at pericardiocentesis by both emergency and cardiology staff were hindered by clotted blood, and so a left lateral thoracotomy was performed in the ED due to loss of pulse and lack of immediate availability of an operating room. A limited pericardial incision was made to allow drainage of sufficient blood to relieve tamponade while avoiding catastrophic blood loss from the underlying lesion, which turned out to be a 1.5-cm hole in the right ventricular outflow tract. The patient made a full recovery.

Cardiac dysrhythmias are a common problem in the United States. Radiofrequency ablation is being used more frequently as a treatment for these diagnoses. Although rare, serious complications such as cardiac tamponade have been reported as a result of ablation procedures. Traditionally, emergency department (ED) thoracotomy has been reserved for cases of traumatic arrest only. We report a case of a successful modified ED thoracotomy in a patient with postablation cardiac tamponade and subsequent obstructive shock who failed intravenous fluid resuscitation, pressor administration, and multiple attempts at pericardiocentesis. In this case, a modified approach was used to incise the pericardium. Although this was associated with large blood loss, we believed that using the traditional method of completely removing the pericardium would have resulted in uncontrolled hemorrhage. Instead, our method led to successful resuscitation of the patient until definitive care was available. A smaller pericardial incision than is traditionally used during ED thoracotomy deserves further consideration and research to determine whether and when it may be most useful as a temporizing treatment of cardiac tamponade when other methods have failed.

Modified Emergency Department Thoracotomy for Postablation Cardiac Tamponade
Annals of Emergency Medicine In Press – Full Text Available here from Annals site at time of blogging

All Updates, PHARM, Resus, Trauma

More on needle thoracostomy for tension pneumothorax

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Thanks to Dr. Matthew Oliver for highlighting these articles to me.
The standard teaching of placing a handy iv catheter in the 2nd intercostal space, midclavicular line for tension pneumothorax has been challenged by previous studies suggesting about a third of adults have a chest wall that is too thick for a standard 4.5 to 5 cm needle.
Some have therefore suggested that a lateral approach may be more appropriate.
Three studies this month provide more, although not entirely consistent, information.
An ultrasound study differed from previous CT studies by suggesting that most patients will have chest wall thickness (CWT) less than 4.5 cm, and found that the CW was thicker in the lateral area (4th intercostal space, midaxillary line)1.
In a cadaveric model, needle thoracostomy was successfully placed (confirmed by thoracotomy) in all attempts at the fifth intercostal space at the midaxillary line but in only just over half of insertions at the traditional second intercostal position2.
In a further study of trauma CT scans, measured CWT suggests that the lateral approach is less likely to be successful than the anterior approach, and the anterior approach may fail in many patients as well3.

The take home message for us must therefore remain that needle thoracostomy for tension pneumothorax might not be successful with a standard iv catheter, regardless of which approach is used. If tension pneumothorax is a possibility in the deteriorating patient and needle decompression has been unsuccessful, an alternative means of decompression (or ruling out pneumothorax) must be employed.

1. Ultrasound determination of chest wall thickness: implications for needle thoracostomy
Am J Emerg Med. 2011 Nov;29(9):1173-7
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Objective: Computed tomography measurements of chest wall thickness (CWT) suggest that standard- length angiocatheters (4.5 cm) may fail to decompress tension pneumothoraces. We used an alternative modality, ultrasound, to measure CWT. We correlated CWT with body mass index (BMI) and used national data to estimate the percentage of patients with CWT greater than 4.5 cm.

Methods: This was an observational, cross-sectional study of a convenience sample. We recorded standing height, weight, and sex. We measured CWT with ultrasound at the second intercostal space, midclavicular line and at the fourth intercostal space, midaxillary line on supine subjects. We correlated BMI (weight [in kilograms]/height2 [in square meters]) with CWT using linear regression. 95% Confidence intervals (CIs) assessed statistical significance. National Health and Nutrition Examination Survey results for 2007-2008 were combined to estimate national BMI adult measurements.

Results: Of 51 subjects, 33 (65%) were male and 18 (35%) were female. Mean anterior CWT (male, 2.1 cm; CI, 1.9-2.3; female, 2.3 cm; CI, 1.7-2.7), lateral CWT (male, 2.4 cm; CI, 2.1-2.6; female, 2.5 cm; CI 2.0-2.9), and BMI (male, 27.7; CI, 26.1-29.3; female, 30.0; CI, 25.8-34.2) did not differ by sex. Lateral CWT was greater than anterior CWT (0.2 cm; CI, 0.1-0.4; P < .01). Only one subject with a BMI of 48.2 had a CWT that exceeded 4.5 cm. Using national BMI estimates, less than 1% of the US population would be expected to have CWT greater than 4.5 cm.
Conclusions: Ultrasound measurements suggest that most patients will have CWT less than 4.5 cm and that CWT may not be the source of the high failure rate of needle decompression in tension pneumothorax.

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2. Anterior versus lateral needle decompression of tension pneumothorax: comparison by computed tomography chest wall measurement.
Acad Emerg Med. 2011 Oct;18(10):1022-6
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Objectives:  Recent research describes failed needle decompression in the anterior position. It has been hypothesized that a lateral approach may be more successful. The aim of this study was to identify the optimal site for needle decompression.

Methods:  A retrospective study was conducted of emergency department (ED) patients who underwent computed tomography (CT) of the chest as part of their evaluation for blunt trauma. A convenience sample of 159 patients was formed by reviewing consecutive scans of eligible patients. Six measurements from the skin surface to the pleural surface were made for each patient: anterior second intercostal space, lateral fourth intercostal space, and lateral fifth intercostal space on the left and right sides.

Results:  The distance from skin to pleura at the anterior second intercostal space averaged 46.3 mm on the right and 45.2 mm on the left. The distance at the midaxillary line in the fourth intercostal space was 63.7 mm on the right and 62.1 mm on the left. In the fifth intercostal space the distance was 53.8 mm on the right and 52.9 mm on the left. The distance of the anterior approach was statistically less when compared to both intercostal spaces (p <  0.01).
Conclusions:  With commonly available angiocatheters, the lateral approach is less likely to be successful than the anterior approach. The anterior approach may fail in many patients as well. Longer angiocatheters may increase the chances of decompression, but would also carry a higher risk of damage to surrounding vital structures.

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3. Optimal Positioning for Emergent Needle Thoracostomy: A Cadaver-Based Study
J Trauma. 2011 Nov;71(5):1099-1103/a>
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Background:  Needle thoracostomy is an emergent procedure designed to relieve tension pneumothorax. High failure rates because of the needle not penetrating into the thoracic cavity have been reported. Advanced Trauma Life Support guidelines recommend placement in the second intercostal space, midclavicular line using a 5-cm needle. The purpose of this study was to evaluate placement in the fifth intercostal space, midaxillary line, where tube thoracostomy is routinely performed. We hypothesized that this would result in a higher successful placement rate.

Methods:  Twenty randomly selected unpreserved adult cadavers were evaluated. A standard 14-gauge 5-cm needle was placed in both the fifth intercostal space at the midaxillary line and the traditional second intercostal space at the midclavicular line in both the right and left chest walls. The needles were secured and thoracotomy was then performed to assess penetration into the pleural cavity. The right and left sides were analyzed separately acting as their own controls for a total of 80 needles inserted into 20 cadavers. The thickness of the chest wall at the site of penetration was then measured for each entry position.

Results:  A total of 14 male and 6 female cadavers were studied. Overall, 100% (40 of 40) of needles placed in the fifth intercostal space and 57.5% (23 of 40) of the needles placed in the second intercostal space entered the chest cavity (p < 0.001); right chest: 100% versus 60.0% (p = 0.003) and left chest: 100% versus 55.0% (p = 0.001). Overall, the thickness of the chest wall was 3.5 cm ± 0.9 cm at the fifth intercostal space and 4.5 cm ± 1.1 cm at the second intercostal space (p < 0.001). Both right and left chest wall thicknesses were similar (right, 3.6 cm ± 1.0 cm vs. 4.5 cm ± 1.1 cm, p = 0.007; left, 3.5 ± 0.9 cm vs. 4.4 cm ± 1.1 cm, p = 0.008).
Conclusions:In a cadaveric model, needle thoracostomy was successfully placed in 100% of attempts at the fifth intercostal space but in only 58% at the traditional second intercostal position. On average, the chest wall was 1 cm thinner at this position and may improve successful needle placement. Live patient validation of these results is warranted.

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Update October 2012: See this post about a further CT-scan based study favouring the 5th ICS compared with the 2nd

All Updates, PHARM, Resus, Trauma, Ultrasound

Tension pneumo treatment and chest wall thickness

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An interesting ultrasound-based study challenges the assertion that a significant proportion of adults have a chest wall that is too thick for a standard iv cannula to reach the pleural space when attempting to decompress a tension pneumothorax. Perhaps there are other factors that make this technique so frequently ineffective.
The authors postulate that ultrasound measurements of chest wall thickness might be less than those obtained by CT scan due to the downward pressure on the tissues caused when the ultrasound transducer is placed on the chest, something that may also occur when a cannula is being pushed in, but would not be maintained after insertion of a cannula, perhaps leading to subsequent misplacement as the tissues recoil.
My view is that needle decompression might buy you time as a holding measure, but the patient with a tension pneumothorax will need a thoracostomy sooner rather than later.


Objective: Computed tomography measurements of chest wall thickness (CWT) suggest that standard- length angiocatheters (4.5 cm) may fail to decompress tension pneumothoraces. We used an alternative modality, ultrasound, to measure CWT. We correlated CWT with body mass index (BMI) and used national data to estimate the percentage of patients with CWT greater than 4.5 cm.

Methods: This was an observational, cross-sectional study of a convenience sample. We recorded standing height, weight, and sex. We measured CWT with ultrasound at the second intercostal space, midclavicular line and at the fourth intercostal space, midaxillary line on supine subjects. We correlated BMI (weight [in kilograms]/height2 [in square meters]) with CWT using linear regression. 95% Confidence intervals (CIs) assessed statistical significance. National Health and Nutrition Examination Survey results for 2007-2008 were combined to estimate national BMI adult measurements.

Results: Of 51 subjects, 33 (65%) were male and 18 (35%) were female. Mean anterior CWT (male, 2.1 cm; CI, 1.9-2.3; female, 2.3 cm; CI, 1.7-2.7), lateral CWT (male, 2.4 cm; CI, 2.1-2.6; female, 2.5 cm; CI 2.0-2.9), and BMI (male, 27.7; CI, 26.1-29.3; female, 30.0; CI, 25.8-34.2) did not differ by sex. Lateral CWT was greater than anterior CWT (0.2 cm; CI, 0.1-0.4; P <.01). Only one subject with a BMI of 48.2 had a CWT that exceeded 4.5 cm. Using national BMI estimates, less than 1% of the US population would be expected to have CWT greater than 4.5 cm.
Conclusions: Ultrasound measurements suggest that most patients will have CWT less than 4.5 cm and that CWT may not be the source of the high failure rate of needle decompression in tension pneumothorax.

Ultrasound determination of chest wall thickness: implications for needle thoracostomy

Am J Emerg Med. 2011 Nov;29(9):1173-7

All Updates

Saving Lives Through Failure

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Think about what you would do if faced with the following situation:

You sedate and paralyse a patient with severe injuries in order to intubate them. You are unable to intubate due to a poor view and massive orofacial haemorrhage. An iGel provides temporary oxygenation while you prepare for a surgical airway.

Your first surgical airway attempt fails due to insertion of the bougie through a false (too superficial) passage. You spot your mistake and re-do the procedure successfully with a deeper incision. The patient’s airway is secure and there is good oxygenation and ventilation.

You discover that a colleague has videoed the procedure on his iPhone. However he only captured the first, unsuccessful attempt. The patient is not identifiable in the close up video. It’s late at night and only he and you know of the existence of the video. He asks you what you want him to do with it.



Do you…
(a) Ask your colleague to delete the video?
(b) Watch the video with him and look for learning points, and then delete it?
(c) Ask him for a copy of it and request that he doesn’t show it to anyone else?
(d) Other course of action
Consider your course of action given this situation, and then click below to reveal what my colleague did recently in exactly the same scenario…
[EXPAND What did he do?]
(d) He did something else entirely: he got a copy of the video, burned it onto a CD, and left it on his boss’s desk!

It takes a certain kind of practitioner to risk embarrassment and criticism in the pursuit of the greater educational good.

He had already ascertained what he would need to do differently next time, so had nothing personal to gain from his chosen action.

Instead, he believed that sharing the video would help prevent his colleagues from repeating the same mistake, and help his supervisors review their cricothyroidotomy training in order to better prepare their team for the procedure. Ultimately, this gesture was directed towards the good of our patients.

His actions may have saved more than one life that evening.

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Acute Med, All Updates, Resus

Needle versus mini-chest tube for pneumothorax

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A mini-chest tube with Heimlich valve was an alternative to needle aspiration in patients with spontaneous pneumothorax, with some apparently favourable outcomes in this small study. The authors do not specify what type of chest tube they used but report it was 12 Fr diameter. They highlight an interesting difference in guidelines for the treatment of spontaneous primary pneumothorax:
“Traditional preference has been for chest tube insertion and admission to the ward. British Thoracic Society recommends needle aspiration (NA) as the initial treatment of choice, but American College of Chest Physicians Consensus prefers insertion of small-bore catheters (≤14F) or chest tubes (16-22F).”


OBJECTIVES: The aim of this study was to compare outcomes and complications associated with needle aspiration (NA) and minichest tube (MCT) insertion with Heimlich valve attachment in the treatment of primary spontaneous pneumothorax at an emergency department (ED).

METHODS: Patients presenting with primary spontaneous pneumothorax were randomized to NA or MCT. They had repeat chest x-rays immediately after the procedure and 6 hours later. Patients who underwent NA were discharged if repeat x-rays showed less than 10% pneumothorax. Those who had MCT were discharged if repeat x-rays did not show worsening of pneumothorax. They were reviewed at the outpatient clinic within 3 days. The primary outcomes of interest were failure rate and admission rate. The secondary outcomes were complication rate, pain and satisfaction scores, length of hospital stay, and rate of full recovery during outpatient follow-up.

RESULTS: There were 48 patients whose mean age was 25 years. We found no difference in failure rate between the groups, except that there were more MCT (24%) than NA patients (4%) with complete expansion at first review (difference, -0.20; 95% confidence interval, -0.38 to -0.01). Thirty-five percent of NA group and 20% of MCT group needed another procedure at the ED. Fifty-two percent of NA patients and 28% of MCT patients were admitted from the ED to the inpatient ward. Nine percent and 12%, respectively, of patients who had NA and MCT were admitted from the review clinic. Both groups of patients had equivalent pain scores, satisfaction scores, and complication rates.

CONCLUSION: Both MCT and NA allowed safe management of primary spontaneous pneumothorax in the outpatient setting.

A randomized controlled trial comparing minichest tube and needle aspiration in outpatient management of primary spontaneous pneumothorax
Am J Emerg Med. 2011 Nov;29(9):1152-7

Acute Med, All Updates, ICU, Resus

AF in sepsis and risk of stroke

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Atrial fibrillation can occur in the setting of severe sepsis, and often presents a therapeutic conundrum for critical care physicians, in that it can be relatively resistant to treatment until the sepsis has resolved, and its prognostic significance is unclear. A new study on a massive dataset shows atrial fibrillation in the setting of severe sepsis is associated with an increased risk of stroke and increased hospital mortality. Patients with severe sepsis who developed new-onset AF had a greater risk of in-hospital stroke than patients with preexisting AF and individuals without a history of AF.


Context New-onset atrial fibrillation (AF) has been reported in 6% to 20% of patients with severe sepsis. Chronic AF is a known risk factor for stroke and death, but the clinical significance of new-onset AF in the setting of severe sepsis is uncertain.

Objective To determine the in-hospital stroke and in-hospital mortality risks associated with new-onset AF in patients with severe sepsis.

Design and Setting Retrospective population-based cohort of California State Inpatient Database administrative claims data from nonfederal acute care hospitals for January 1 through December 31, 2007.

Patients Data were available for 3 144 787 hospitalized adults. Severe sepsis (n = 49 082 [1.56%]) was defined by validated International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 995.92. New-onset AF was defined as AF that occurred during the hospital stay, after excluding AF cases present at admission.

Main Outcome Measures A priori outcome measures were in-hospital ischemic stroke (ICD-9-CM codes 433, 434, or 436) and mortality.

Results Patients with severe sepsis were a mean age of 69 (SD, 16) years and 48% were women. New-onset AF occurred in 5.9% of patients with severe sepsis vs 0.65% of patients without severe sepsis (multivariable-adjusted odds ratio [OR], 6.82; 95% CI, 6.54-7.11; P < .001). Severe sepsis was present in 14% of all new-onset AF in hospitalized adults. Compared with severe sepsis patients without new-onset AF, patients with new-onset AF during severe sepsis had greater risks of in-hospital stroke (75/2896 [2.6%] vs 306/46 186 [0.6%] strokes; adjusted OR, 2.70; 95% CI, 2.05-3.57; P < .001) and in-hospital mortality (1629 [56%] vs 18 027 [39%] deaths; adjusted relative risk, 1.07; 95% CI, 1.04-1.11; P < .001). Findings were robust across 2 definitions of severe sepsis, multiple methods of addressing confounding, and multiple sensitivity analyses.
Conclusion Among patients with severe sepsis, patients with new-onset AF were at increased risk of in-hospital stroke and death compared with patients with no AF and patients with preexisting AF.

Incident Stroke and Mortality Associated With New-Onset Atrial Fibrillation in Patients Hospitalized With Severe Sepsis
JAMA. 2011 Nov 13. [Epub ahead of print]

Acute Med, All Updates

AMI mortality increased as the number of risk factors declined

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An interesting finding: in patients with myocardial infarction, hospital mortality increased consistently as the number of risk factors declined. There was also an inverse relationship between age and the number of coronary heart disease risk factors.
The authors discuss the possibility that the some of the zero risk factor group may have had risk factors unknown to the patient or not reported in the history, or may have had other factors that influence the disease, for example insulin resistance, abdominal obesity, psychosocial factors, poor nutrition, or physical inactivity.


Context Few studies have examined the association between the number of coronary heart disease risk factors and outcomes of acute myocardial infarction in community practice.

Objective To determine the association between the number of coronary heart disease risk factors in patients with first myocardial infarction and hospital mortality.

Design Observational study from the National Registry of Myocardial Infarction, 1994-2006.

Patients We examined the presence and absence of 5 major traditional coronary heart disease risk factors (hypertension, smoking, dyslipidemia, diabetes, and family history of coronary heart disease) and hospital mortality among 542 008 patients with first myocardial infarction and without prior cardiovascular disease.

Main Outcome Measure All-cause in-hospital mortality.

Results A majority (85.6%) of patients who presented with initial myocardial infarction had at least 1 of the 5 coronary heart disease risk factors, and 14.4% had none of the 5 risk factors. Age varied inversely with the number of coronary heart disease risk factors, from a mean age of 71.5 years with 0 risk factors to 56.7 years with 5 risk factors (P for trend < .001). The total number of in-hospital deaths for all causes was 50 788. Unadjusted in-hospital mortality rates were 14.9%, 10.9%, 7.9%, 5.3%, 4.2%, and 3.6% for patients with 0, 1, 2, 3, 4, and 5 risk factors, respectively. After adjusting for age and other clinical factors, there was an inverse association between the number of coronary heart disease risk factors and hospital mortality adjusted odds ratio (1.54; 95% CI, 1.23-1.94) among individuals with 0 vs 5 risk factors. This association was consistent among several age strata and important patient subgroups.
Conclusion Among patients with incident acute myocardial infarction without prior cardiovascular disease, in-hospital mortality was inversely related to the number of coronary heart disease risk factors.

Number of Coronary Heart Disease Risk Factors and Mortality in Patients With First Myocardial Infarction
JAMA. 2011;306(19):2158-2159

Acute Med, All Updates, ICU, Kids, PHARM, Resus

2011 Asthma Guidelines

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The British Thoracic Society / SIGN Guidelines on asthma have been updated for 2011. There don’t seem to be any modificiations to the sections on acute severe asthma which were updated in 2009 and blogged here, although the treatment algorithms seem to be presented in a slightly different format and therefore are reproduced here:

Management of acute severe asthma in adults in hospital

Management of acute asthma in children in hospital

All Updates, ICU, PHARM, Resus

Preoxygenation and Prevention of Desaturation

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This paper is an excellent review article citing the cogent relevant evidence for optimal preoxygenation prior to RSI in the critically ill patient. The evidence has been interpreted with pertinent recommendations by two of the world’s heavy hitters in emergency medicine – Scott Weingart and Rich Levitan. If you can get a full text copy of the paper, laminate Figure 3 (‘Sequence of Preoxygenation and Prevention of Desaturation‘) and stick it to the wall in your resus bay!
The points covered include:

  • Why preoxygenate? Preoxygenation extends the duration of safe apnoea and should be considered mandatory, even in the crashing patient.
  • Standard non-rebreather facemasks set to the highest flow rate of oxygen possible should be used.
  • Allow 8 vital capacity breaths for co-operative patients or 3 minutes for everyone else.
  • Increasing mean airway pressure by CPAP/NIV or PEEP valves improves preoxygenation. However caution should be used in hypovolaemic shocked patients (decreased venous return) and should be reserved for patients who cannot preoxygenate >93-95% with high FiO2.
  • 20-degree head up or reverse Trendelenburg (in suspected trauma) improves pre oxygenation.
  • Apnoeic diffusion oxygenation can extend safe duration of apnoea after the RSI. Set nasal cannulae at 15L/min and leave on during intubation attempts. Ensure upper airway patency (ear to sternal notch and jaw thrust).
  • Active ventilation during onset of muscle relaxation should be assessed on a case by case basis and reserved for patients at high risk of desaturation (6-8 breaths per minute slowly, TV 6-7ml/kg).
  • If there is a high risk of desaturation rocuronium (1.2 mg/kg) may provide a longer duration of safe apnoea than suxamethonium with similar onset time.

Preoxygenation and Prevention of Desaturation During Emergency Airway Management
Ann Emerg Med. 2011 Nov 1. [Epub ahead of print]
[EXPAND Abstract]

Patients requiring emergency airway management are at great risk of hypoxemic hypoxia because of primary lung pathology, high metabolic demands, anemia, insufficient respiratory drive, and inability to protect their airway against aspiration. Tracheal intubation is often required before the complete information needed to assess the risk of periprocedural hypoxia is acquired, such as an arterial blood gas level, hemoglobin value, or even a chest radiograph. This article reviews preoxygenation and peri-intubation oxygenation techniques to minimize the risk of critical hypoxia and introduces a risk-stratification approach to emergency tracheal intubation. Techniques reviewed include positioning, preoxygenation and denitrogenation, positive end expiratory pressure devices, and passive apneic oxygenation.

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Acute Med, All Updates, Resus

Delayed diagnosis of aortic dissection

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Being female or having atypical pain is associated with delays to diagnosis of aortic dissection. This recent study also shows that arrival in a non-tertiary hospital is another factor associated with delayed diagnosis. Patients may present with fever, abdominal pain, or heart failure (due to acute aortic insufficiency) that lead the clinician down alternative diagnostic algorithms. The strongest factors associated with operative delay were prolonged time from presentation to diagnosis, race other than white, and history of coronary artery bypass surgery.
Worth remembering at this point that in 2010 the AHA published Guidelines for the Diagnosis and Management of Patients With Thoracic Aortic Disease

Background- In acute aortic dissection, delays exist between presentation and diagnosis and, once diagnosed, definitive treatment. This study aimed to define the variables associated with these delays.

Methods and Results- Acute aortic dissection patients enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and January 2007 were evaluated for factors contributing to delays in presentation to diagnosis and in diagnosis to surgery. Multiple linear regression was performed to determine relative delay time ratios (DTRs) for individual correlates. The median time from arrival at the emergency department to diagnosis was 4.3 hours (quartile 1-3, 1.5-24 hours; n=894 patients) and from diagnosis to surgery was 4.3 hours (quartile 1-3, 2.4-24 hours; n=751). Delays in acute aortic dissection diagnosis occurred in female patients; those with atypical symptoms that were not abrupt or did not include chest, back, or any pain; patients with an absence of pulse deficit or hypotension; or those who initially presented to a nontertiary care hospital (all P<0.05). The largest relative DTRs were for fever (DTR=5.11; P<0.001) and transfer from nontertiary hospital (DTR=3.34; P<0.001). Delay in time from diagnosis to surgery was associated with a history of previous cardiac surgery, presentation without abrupt or any pain, and initial presentation to a nontertiary care hospital (all P<0.001). The strongest factors associated with operative delay were prolonged time from presentation to diagnosis (DTR=1.35; P<0.001), race other than white (DTR=2.25; P<0.001), and history of coronary artery bypass surgery (DTR=2.81; P<0.001).
Conclusions- Improved physician awareness of atypical presentations and prompt transport of acute aortic dissection patients could reduce crucial time variables.

Correlates of Delayed Recognition and Treatment of Acute Type A Aortic Dissection: The International Registry of Acute Aortic Dissection (IRAD)
Circulation. 2011 Nov 1;124(18):1911-1918