This article received a little bit of dissemination, with the assertion that some apparently futile resuscitations may yet be salvaged despite the lack of cardiac activity on ultrasound.
But, this article doesn’t necessarily tell the entire story. It’s a systematic review of several small, poor-quality cardiac arrest cohorts for whom bedside cardiac ultrasonography was performed. In aggregate, there were 378 patients with no cardiac activity visualized during resuscitation – and 9 went on to have return of spontaneous circulation. They calculate this out as an LR of 0.18 for ROSC after finding no cardiac activity.
The problem is, this is the only information we have regarding the context of the ultrasound findings or the performance characteristics of the ultrasonographers at work. The authors also appropriately note that ROSC is not necessarily the ultimate patient-oriented outcome of interest – since we know that most ROSC after cardiac arrest admitted to the hospital still goes on to have a dismal outcome.
I’m not entirely sure what my takeaway should be from this study, and it’s not going to significantly modify my practice. In the appropriate clinical context, a lack of cardiac activity will still lead me to cease resuscitative efforts. It would be extraordinarily helpful to have a larger body of data specifically regarding the patient characteristics of those who did have ROSC despite lack of cardiac activity, to see if there is a usable pattern to this small population of exceptions.
“Bedside Focused Echocardiography as Predictor of Survival in Cardiac Arrest Patients: A Systematic Review”
Category: Resuscitation
Pediatric Intubation – Not Always Successful
This is an observational study of pediatric medical resuscitation, published in Annals of Emergency Medicine, using video to evaluate the frequency of various adverse events during pediatric intubation.
As expected in a teaching institution, there is a fair bit of variability in initial success rates – ranging from 35% first-pass success for pediatrics residents up to 89% for PEM or anesthesia attendings. Overall 52% had success on the first attempt. Unfortunately, 61% experienced at least one adverse event during intubation. These were typically not clinically important with regard to patient-oriented outcomes.
However, what is more entertainingly concerning is how few of the complications make it into the medical record. The written documentation overestimates first-attempt success, underestimates desaturation during the procedure, and even completely omits any mention of one of the two episodes of CPR required during resuscitation.
My guess is that Cincinnati Children’s may have had a documentation quality review after this data were collected.
“Rapid Sequence Intubation for Pediatric Emergency Patients: Higher Frequency of Failed Attempts and Adverse Effects Found by Video Review”
www.ncbi.nlm.nih.gov/pubmed/22424653
The Legend of the Therapeutic Arterial Line
As many Emergency Physicians can probably attest, one of the curious practices of critical care is to catheterize every potential organ system – as though the presence of these catheters in some way improves outcomes. And, the theory is – the non-invasive numbers are not accurate enough upon which to base treatment options.
So, this is a simple study performed in an intensive care unit in which patients with arterial blood pressure monitoring receive non-invasive measurements at the arm, ankle, and thigh (not everyone in the ICU will have an accessible arm). And, essentially, the results show – even in the critically ill, even on vasopressors – that the mean arterial pressure in the arm is probably a accurate measurement, with a mean bias of 3.4 mmHg. The systolic and diastolic numbers, as well as the ankle and thigh values, were not quite as precise or accurate.
For the Emergency Department, it probably tells you it’s OK to do what you probably already do – critically ill patients get arterial lines only if there is a luxury of time available. Someone else with half an hour to spare can poke around fruitlessly in the radial wrist before surrendering to the femoral….
“Noninvasive monitoring of blood pressure in the critically ill: Reliability according to the cuff site (arm, thigh, or ankle)”
www.ncbi.nlm.nih.gov/pubmed/22425818
Lactate Clearance and ScvO2 Goals in Sepsis
Early goal-directed sepsis care is successful – but no one can say precisely what makes it successful. Hawthorne effect? Early antibiotics appear to have uncertain association with better outcomes. Is it the blood? Is it meeting the central venous oxygenation goal of >70%?
Other studies have shown equivalency in outcomes while performing serial lactic acid measurements, and this is another study in the same vein. 203 patients form the analysis cohort, in which 93 received management decisions based on lactate clearance and 110 which received management decisions based on the ScvO2. All included patients had both values measured simultaneously, but were blinded to the opposition.
And, this is another study where the two measures are different but similar – which is probably why the analysis is so convoluted. Of the 203 enrolled, 175 either fortuitously or by design met the ScvO2 goal, while 178 met the lactate clearance goal. Meeting the ScvO2 goal led to a death rate of 21% and meeting the lactate clearance goal led to a death rate of 17%. There was no difference in therapeutic interventions between the ScvO2 goal group and the lactate clearance group.
However, if you met the lactate clearance without meeting the ScvO2 goal, you had an 8% (2/25) mortality, while the ScvO2 group that didn’t clear lactate had a 41% mortality (9/22). Unfortunately, there were a number of baseline differences between the groups, and it’s hard to draw any conclusions or hypotheses from this finding. It’s also clear they didn’t identify any specific interventions that improved survival in their cohort – and, more appropriately, simply observed that poor lactate clearance simply portends a worse outcome, without any specific recommendation on how to address it.
“Prognostic Value and Agreement of Achieving Lactate Clearance or Central Venous Oxygen Saturation Goals During Early Sepsis Resuscitation”
Uninterrupted CPR is Better Than Interrupted
This is from King County, which has been publishing retrospective pre- and post- intervention outcomes related to out-of-hospital cardiac arrest for several years now. This article focuses on the AHA guidelines for PEA and asystole, and the changes that were made in 2004 and 2005. Those changes, if you recall, involve fewer pauses for pulse and rhythm checks and decreasing the number of ventilations.
Good news! You were 1.5 times more likely to survive neurologically intact to hospital discharge after the introduction of the new guidelines. Bad news: good neurological outcome was still only 5.1%, up from 3.4%. So, yes, this is another piece of evidence supporting the “uninterrupted, high-quality CPR” concept, but perhaps the other important question that need be asked at the same time is: how can we reduce the unnecessary resource expenditure associated with attempted resuscitation for the 95% that doesn’t benefit?
“Impact of Changes in Resuscitation Practice on Survival and Neurological Outcome After Out-of-Hospital Cardiac Arrest Resulting From Nonshockable Arrhythmias”
http://www.ncbi.nlm.nih.gov/pubmed/22474256
Post-Arrest Troponin Measurements Predict Little
Taking post-arrest patients to cardiac catheterization improves outcomes – as long as they have a cardiac occlusion as the underlying etiology of their arrest. Otherwise, you’re simply delaying the diagnosis and treatment of alternative causes, as well as post-arrest ICU-level care. Therefore, if there is some clinical feature that can be identified on initial Emergency Department evaluation that predicts a coronary occlusion, that would be of great value.
So, this is a retrospective analysis of a prospective registry of out-of-hospital arrests from Paris, where much of the post-arrest catheterization work has been done. And, unfortunately, there isn’t any useful association – 92% of their patients had elevated troponin on initial evaluation. There was a nonsignificant trend towards higher troponin levels in patients with coronary occlusion, but even at their “optimum” cut-off of 4.66ng/mL, the sensitivity and specificity were nearly coin-flip at 66% each. A troponin of 31ng/mL was required for 95% specificity.
ST-segment elevation, incidentally, was more predictive of a coronary occlusion – OR 10.19 (CI 5.39 to 19.26).
“Can early cardiac troponin I measurement help to predict recent coronary occlusion in out-of-hospital cardiac arrest survivors?”
http://www.ncbi.nlm.nih.gov/pubmed/22488008
More Nails In the Coffin For Epinephrine
The news for epinephrine in cardiac arrest keeps getting worse – it restarts the heart, but at what cost, and with what outcomes?
This is a study, published in JAMA, of 417,188 out-of-hospital cardiac arrest patients in Japan – only 15,030 of which received epinephrine during prehospital transport – a far cry from the U.S., where the toolbox has typically already been emptied prior to the ED. Nearly every baseline characteristic favored the epinephrine group – more witnessed arrests, more received bystander CPR, a physician was more frequently in the ambulance, more patients in ventricular fibrillation/PEA. However, more of these patients also received an advanced airway, which has also been associated with worse outcomes.
In their unadjusted analysis, the epinephrine cohort was three times as likely to have ROSC, and had an OR of 1.15 to be alive at one month. However, they were half as likely to be functional as the non-epinephrine survivors. Then, when they do all their statistical adjustments for all the favorable baseline factors in the epinephrine cohort, all these numbers become less favorable for epinephrine. They also do a propensity-matched cohort of 26,802 patients that has favorable ROSC with epinephrine, but dismal 1 month and functional outcomes.
This data is from before the era of routine hypothermia – which may be beneficial – but it certainly supports what we already expected regarding the damaging physiologic effects of epinephrine while senselessly flogging the heart back into action.
“Prehospital Epinephrine Use and Survival Among Patients With Out-of-Hospital Cardiac Arrest”
http://jama.ama-assn.org/content/307/11/1161.short
Is It Reasonable to Keep Using Vasopressin in Shock?
The authors of this meta-analysis seem to think so.
Unfortunately, they identify a very heterogenous set of evidence for analysis, which reduces the statistical power of every comparison. They identify only a couple studies of vasopressin vs. placebo, and most of their studies are vasopressin vs. an increased dose of norepinephrine.
It’s hard to generate any unreasonable conclusion from this data – the error bars cross one, so you can either take this as permission to drop vasopressin from your usage patterns because its use has no measurable mortality benefit, or you can continue to use vasopressin because it doesn’t seem to be harmful, and allows you to reduce the dose of norepinephrine.
I’d really like to see more vasopressin vs. control – there’s only one reasonably sized vasopressin vs. placebo trial – and it heavily, but non-significantly, favors control with a risk ratio for mortality of 1.94 (0.74 to 5.10).
More to be done!
“Vasopressin for treatment of vasodilatory shock: an ESICM systematic review and meta-analysis”
The Harmful Rush To Hypothermia
Mild hypothermia seems to be a clinically useful therapeutic modality for improving neurologic outcomes following return of spontaneous circulation in cardiac arrest.
However, like any emerging therapy, the precise details regarding which patients are most likely to benefit and how to best apply it are still in flux. This is an Italian registry study that gathered prospective data on all individuals at 17 hospitals who underwent therapeutic hypothermia following cardiac arrest. The specific question asked by these authors is regarding the optimal time for initiation of hypothermia – using 2 hours after ROSC as their cut-off.
Turns out, they found an association between “early” (< 2 hours to initiation) therapeutic hypothermia and worsened mortality – 47% mortality vs. 23% mortality in the ICU. This ~20% absolute difference in outcomes holds up over the 6 month follow-up period. No difference in cerebral performance category is observed between the two groups, although there is a nonsignificant trend towards better CPC in the “early” group.
Hard to know what to actually do with data. Is early hypothermia truly harmful? Because of the observational design, it’s hard to say whether there aren’t confounding baseline differences in the “late” population that produces selection bias for higher survival rates. Or, are the mortality rates higher in the early group because patients are incompletely resuscitated before initiating hypothermia?
More questions, no answers.
“Early- versus late-initiation of therapeutic hypothermia after cardiac arrest: Preliminary observations from the experience of 17 Italian intensive care units”
Too Many Traumatic Arrests Are Transported
Traumatic arrest in the field – except in the narrowest of circumstances – has universally dismal outcomes. Yet, As the authors of this study observe, a great number of these patients continue to be transported to hospitals.
This is a retrospective review of a prospective trauma registry at Sinai in Chicago in which all traumatic patients with pre-hospital arrest were considered. Patients were excluded for pediatrics, medical causes, drowning/electrocution injuries, and if the prehospital time was less than 15 minutes. Essentially, they were looking at guidelines from the ACS Committee on Trauma for termination of resuscitation in the out of hospital setting – pulseless, apneic, no organized ECG activity, or unresponsive to 15 minutes of resuscitation.
They identified 428 patients in their cohort – and found that 294 of them were transported in violation of guidelines. Of the inappropriately transported patients, 93% were declared dead in the ED and the remaining 6.8% (20 patients) survived the ED. Of those 20, 12 died in surgery, 8 made it to the ICU, and 7 died. A single, neurologically devastated, patient survived to discharge to a long-term care facility with a GCS of 6.
The total hospital charges incurred for the futile resuscitation of these patients totaled $3.8 million – a figure that excludes the EMS charges as well as the long-term care facility charges for the patient with GCS 6.
And this is just a single hospital.
“The Consequences of Noncompliance With Guidelines for Withholding or Terminating Resuscitation in Traumatic Cardiac Arrest Patients”
http://www.ncbi.nlm.nih.gov/pubmed/21986740