If you have a BVM (Bag Valve Mask resuscitator), you should not need naloxone. The problem is inadequate respiration, not inadequate naloxonation.

- Rogue Medic

Who Needs a 12 Lead ECG?

ResearchBlogging.org
 

Do we do too many 12 lead ECGs on patients who do not have chest pain?

This is something that some people worry about.

Save the electrodes!

Those poor little electrodes are being abused!

Are electrodes being abused?
 

Women and the elderly with STEMI are particularly likely to present with atypical chief complaints such as dyspnea and weakness. Such patients experience significant delays in door-to-ECG time and treatment and have increased morbidity and mortality compared with patients who present with chest pain.5,9-12 [1]

 

Tiredness/weakness is the second best predictor of STEMI (ST segment Elevation Myocardial Infarction).

After chest pain (pressure, tightness, heaviness, squeezing, et cetera), the best predictor of STEMI is dyspnea in akll age ranges, but dyspnea indicates 20% of STEMIs in patients over 80 years old.

Are we helping anyone by avoiding 12 lead ECG (ElectroCardioGram) assessment?
 

Presenting chief complaints among 6,464 patients with STEMI. Chest pain decreased in frequency with age, whereas a chief complaint of dyspnea, weakness, syncope, or altered mental status all increased in frequency with age.[1]

 


Click on images to make them larger.
 


 

The advantage of a logarithmic chart is that there is greater distinction among the smaller numbers (such as the other complaints that make up less than 5% in the image above). The disadvantage is that large changes are flattened. I modified the dyspnea line to show how it would look on a linear scale (from 5% to 20%). As you can see, the ability to predict STEMI increases dramatically with age – more dramatically than the logarithmic scale suggests.
 


 

How should we remember all of this?

The authors came up with a nice simple flow chart (below).

This is for the ED, but is there a good reason for EMS to ignore these STEMIs?
 


 

Even in the 18-49 year old patients, dyspnea is about as likely to predict a STEMI as weakness is likely to predict a STEMI in an 80+ year old patient.

Chest pain still indicates about 50% of STEMI patients over 80, but we will miss half of STEMIs in this population if we only do 12 leads on chest pain patients.

Can an 80+ year old patient have a good quality of life after a STEMI?

Absolutely.

Also see When should you get an ECG? at Mill Hill Ave Command.

-

Footnotes:

-

[1] Development and validation of a prioritization rule for obtaining an immediate 12-lead electrocardiogram in the emergency department to identify ST-elevation myocardial infarction.
Glickman SW, Shofer FS, Wu MC, Scholer MJ, Ndubuizu A, Peterson ED, Granger CB, Cairns CB, Glickman LT.
Am Heart J. 2012 Mar;163(3):372-82. doi: 10.1016/j.ahj.2011.10.021.
PMID: 22424007 [PubMed - indexed for MEDLINE]

-

Glickman SW, Shofer FS, Wu MC, Scholer MJ, Ndubuizu A, Peterson ED, Granger CB, Cairns CB, & Glickman LT (2012). Development and validation of a prioritization rule for obtaining an immediate 12-lead electrocardiogram in the emergency department to identify ST-elevation myocardial infarction. American heart journal, 163 (3), 372-82 PMID: 22424007

.

The Failure of LUCAS to Improve Outcomes in the LINC Trial

ResearchBlogging.org
 

We love gadgets in EMS.

Dr. Bryan Bledsoe tells us that if we paint it orange and put a star of life on it, we can sell any product for a lot more money.

How much would you pay to not improve outcomes?

$10,000.00?

$20,000.00?

$30,000.00?

$40,000.00?

$50,000.00?

Why ask how much money we would pay for no improvement?

There is no price that justifies no improvement.
 


Image credit.
 

Experimental studies with the mechanical chest compression device used in this study have shown improved organ perfusion pressures, enhanced cerebral blood flow, and higher end-tidal CO2 compared with manual CPR, with the latter also supported by clinical data.9- 11 [1]

 

These are surrogate endpoints. What are surrogate endpoints? They are not outcomes that matter. Who cares if you got the pulse oximetry to 100% if the patient died? Survival matters.

There is good evidence that blood-letting improves surrogate endpoints.[2] We know that blood-letting kills.

Should we start bleeding patients based on improved surrogate endpoints?

Of course not. Treating patients based on surrogate endpoints kills patients.

There is good evidence that the LUCAS improves surrogate endpoints.

Should we start treating patients with the LUCAS based on surrogate endpoints?

Of course not. Treating patients based on surrogate endpoints kills patients.
 

The current sample size has a 95% confidence interval for the 4-hour survival ranging from −3.3% to +3.2%. Translated another way, while the point estimate for treatment effect was near 0.0, our study could not rule out the possibility of a 3.2% benefit or a similarly sized harm from mechanical CPR relative to standard CPR.[1]

 

What do you mean by this could be harmful?

The apparent benefit could be misleading and the device really could be more harmful than beneficial.

Anyone telling you otherwise is not being honest.

The authors are honest.
 

Thus, in clinical practice, CPR with this mechanical device using the presented algorithm can be delivered without major complications but did not result in improved outcomes compared with manual chest compressions.[1]

 

If you want to use the LUCAS because you believe in miracles, you are not discussing medicine. The LUCAS is a medical device that has failed to improve outcomes.

Dr. Brooks Walsh also explains the failure of the LUCAS in this study in “We had a LUCAS save!” – No, you didn’t.

Also see-

The LUCAS, Research, and Wishful Thinking.

In Defense of No Improvement by Medic Madness – Part I.

-

Footnotes:

-

[1] Mechanical chest compressions and simultaneous defibrillation vs conventional cardiopulmonary resuscitation in out-of-hospital cardiac arrest: the LINC randomized trial.
Rubertsson S, Lindgren E, Smekal D, Östlund O, Silfverstolpe J, Lichtveld RA, Boomars R, Ahlstedt B, Skoog G, Kastberg R, Halliwell D, Box M, Herlitz J, Karlsten R.
JAMA. 2014 Jan 1;311(1):53-61. doi: 10.1001/jama.2013.282538.
PMID: 24240611 [PubMed - indexed for MEDLINE]

-

[2] Blood-Letting
Br Med J.
1871 March 18; 1(533): 283–291.
PMCID: PMC2260507

-

Rubertsson S, Lindgren E, Smekal D, Östlund O, Silfverstolpe J, Lichtveld RA, Boomars R, Ahlstedt B, Skoog G, Kastberg R, Halliwell D, Box M, Herlitz J, & Karlsten R (2014). Mechanical chest compressions and simultaneous defibrillation vs conventional cardiopulmonary resuscitation in out-of-hospital cardiac arrest: the LINC randomized trial. JAMA : the journal of the American Medical Association, 311 (1), 53-61 PMID: 24240611

.

If We Are Not Competent With Direct Laryngoscopy, We Should Just Say So – Part II

ResearchBlogging.org
 

Continuing from Part I of a paper that could, at best, be described as a convenience sample, since a quarter of patients were excluded from randomization because of attending physician bias.

What were the authors assuming when comparing GVL (GlideScope Video Laryngoscope) with DL (Direct Laryngoscopy) for intubation?
 

Intuitively, devices such as the indirect video laryngoscope should improve intubation performance. As such, this study tested the hypothesis that achieving better visualization during the intubation with the GlideScope Video Laryngoscope would result in a better airway management performance as measured by shorter intubation times.[1]

 

The authors also intuitively assume that shorter intubation times mean better airway management. This suggests that speed is the most important factor in airway management.
 


Image credit.
 

They are probably still preaching the myth of the Golden Hour at Shock Trauma.

Is speed more important than quality?
 

There is an excellent assessment of intubation attempt in this paper.
 

Confirmation of intubation attempt duration and success was identified using closed-circuit video.[1]

 

We should not be relying on self-reported intubation success, unless we aren’t interested in a study of fiction. We do not accurately report intubation success, so an objective measurement of success is essential. This should be applied to EMS, as well.
 

The failed intubation rate was less than 0.5%, but the participants had already excluded over a quarter of the patients, so how impressive is a half a percent failure on 3/4 of patients?

What is the success rate for all patients?
 

For all of the statistics regarding study measures, a p < 0.05 was chosen as the threshold for determining significance.[1]

 

Secondary outcome measures are free shots at finding something “significant,” so they should be required to achieve a higher standard than the 1 in 20 p value of < 0.05.[2]

 

To account for any potential bias from patients not enrolled owing to attending discretion, comparison analysis was performed between the eligible, enrolled patients and the eligible, nonenrolled patients. The data demonstrates that all groups were proportionally similar in their demographics, injury mechanism, ISS, and arrival vital signs (data not shown).[1]

 

And, according to Dr. Newman in the SMART EM podcast, the Mallampati scores of the excluded patients were similar to those of the included patients.
 

Used alone, the Mallampati tests have limited accuracy for predicting the difficult airway and thus are not useful screening tests.[3]

 

We conclude that the prognostic value of the modified Mallampati score was worse than that estimated by previous meta-analyses. Our assessment shows that the modified Mallampati score is inadequate as a stand-alone test of a difficult laryngoscopy or tracheal intubation, but it may well be a part of a multivariate model for the prediction of a difficult tracheal intubation.[4]

 

Do the demographics, injury mechanism, ISS, and arrival vital signs increase the ability of the Mallapati to predicting difficult intubation?
 


Image credit.
 

How do we know that the difficulty was similar between included patients and excluded patients?

Similar Mallampati scores.

How useful are Mallampati scores at predicting difficulty of intubation?
 

The pooled estimates demonstrated that only 35% of the patients, who underwent tracheal intubation with difficulties, were correctly identified with a modified Mallampati test.[4]

 

Does the Mallampati score work well for predicting difficulty of intubation with a video laryngoscope?
 

The clinical use of videolaryngoscopes may change the accuracy of predictors of difficult tracheal intubation and require a different definition of difficult tracheal intubation.[4]

 

The Mallampati score does not appear to be of much use in comparing the excluded patients from the included patients, but that is what the authors use to assure us that the patients are similar.

Mallampati scores compare one aspect of visibility, but how important is visibility for intubation?

To be continued in Part III.

-

Footnotes:

-

[1] Effect of video laryngoscopy on trauma patient survival: a randomized controlled trial.
Yeatts DJ, Dutton RP, Hu PF, Chang YW, Brown CH, Chen H, Grissom TE, Kufera JA, Scalea TM.
J Trauma Acute Care Surg. 2013 Aug;75(2):212-9. doi: 10.1097/TA.0b013e318293103d.
PMID: 23823612 [PubMed - in process]

-

[2] Do multiple outcome measures require p-value adjustment?
Feise RJ.
BMC Med Res Methodol. 2002 Jun 17;2:8. Review.
PMID: 12069695 [PubMed - indexed for MEDLINE]

Free Full Text from BioMed Central.
 

Standard scientific practice, which is entirely arbitrary, commonly establishes a cutoff point to distinguish statistical significance from non-significance at 0.05. By definition, this means that one test in 20 will appear to be significant when it is really coincidental. When more than one test is used, the chance of finding at least one test statistically significant due to chance and incorrectly declaring a difference increases. When 10 statistically independent tests are performed, the chance of at least one test being significant is no longer 0.05, but 0.40.

 

-

[3] A systematic review (meta-analysis) of the accuracy of the Mallampati tests to predict the difficult airway.
Lee A, Fan LT, Gin T, Karmakar MK, Ngan Kee WD.
Anesth Analg. 2006 Jun;102(6):1867-78.
PMID: 16717341 [PubMed - indexed for MEDLINE]

-

[4] Poor prognostic value of the modified Mallampati score: a meta-analysis involving 177 088 patients.
Lundstrøm LH, Vester-Andersen M, Møller AM, Charuluxananan S, L’hermite J, Wetterslev J; Danish Anaesthesia Database.
Br J Anaesth. 2011 Nov;107(5):659-67. doi: 10.1093/bja/aer292. Epub 2011 Sep 26.
PMID: 21948956 [PubMed - indexed for MEDLINE]

Free Full Text from Oxford Journals.

-

Yeatts DJ, Dutton RP, Hu PF, Chang YW, Brown CH, Chen H, Grissom TE, Kufera JA, & Scalea TM (2013). Effect of video laryngoscopy on trauma patient survival: a randomized controlled trial. The journal of trauma and acute care surgery, 75 (2), 212-9 PMID: 23823612

-

Lee A, Fan LT, Gin T, Karmakar MK, & Ngan Kee WD (2006). A systematic review (meta-analysis) of the accuracy of the Mallampati tests to predict the difficult airway. Anesthesia and analgesia, 102 (6), 1867-78 PMID: 16717341

-

Lundstrøm LH, Vester-Andersen M, Møller AM, Charuluxananan S, L’hermite J, Wetterslev J, & Danish Anaesthesia Database (2011). Poor prognostic value of the modified Mallampati score: a meta-analysis involving 177 088 patients. British journal of anaesthesia, 107 (5), 659-67 PMID: 21948956

.

Is Earlier Better for Therapeutic Hypothermia? Part I

ResearchBlogging.org
 

When is the right time to begin TH (Therapeutic Hypothermia) to produce the best outcomes?

In the ICU (Intensive Care Unit)?

In the ED (Emergency Department)?

In the ambulance?

While the patient is still pulseless?

This question was asked in 2010.
 


Click on image to make it larger.
 

Favorable outcomes – 47.5% EMS TH vs 52.6% ED TH.

Worse outcome, but not statistically significant.

Discharge to home – 20.3% EMS TH vs 29.3% ED TH.

Worse outcome, but not statistically significant.

Discharge to rehabilitation – 27.1% EMS TH vs 23.3% ED TH.

Worse outcome, because these patients are not well enough to go home, but not statistically significant.

Dead – 52.5% EMS TH vs 46.6% ED TH.

Worse outcome, but not statistically significant.
 

The great tragedy of Science — the slaying of a beautiful hypothesis by an ugly fact. -Thomas Henry Huxley.
 

EMS TH was added to many EMS protocols because of a lack of clear evidence of harm. EMS needed to Just do something.

The results did not support EMS administration of chilled IV (IntraVenous) fluid for prehospital therapeutic hypothermia, but the study was stopped early, because –
 

At the interim analysis of the first 200 patients, the Steering Committee noted that there was no difference in the primary outcome measure and that it was extremely unlikely that such a difference would emerge between the groups. Therefore, the study was stopped because of futility after 234 patients had been enrolled.[1]

 

In other words – We will not let the numbers convince us that there is no benefit, because numbers that do not support a positive effect are futile?

If the data would have indicated a negative effect, but had not reached statistical significance, should we expect the Steering Committee to support continuing the study, or would they support discontinuing the study early to protect the enrolled patients, but leave the question unanswered?

When studies are discontinued early to protect patients, do they discourage further studies?

When studies are discontinued early to protect patients, do they only endanger future patients?

Or does early termination encourage further studies because there is not clear evidence of harm and we want to believe that our interventions are beneficial?
 

What if it works?

Most proposed treatments do not work, so this is just an excuse to continue using something dangerous. What if it works? is the logical fallacy that is used to justify harming patients with alternative medicine.

We should not harm vulnerable patients because of our unreasonable belief in wishful thinking.
 

If it helps just one patient it is worth it.

This is another logical fallacy, because it completely ignores the harm that the treatment causes.

Some patients will improve after almost any treatment – even cyanide.

That means that alternative medicine advocates could should endorse the use of cyanide, because if it helps just one patient . . . .

We need to have unbiased information about the real benefits (if any) and the real harms (if any), before we encourage using anything on vulnerable patients.
 

Is it good to just do something?

Or

Is it good to help patients?

If our responsibility is to help patients, one of the best ways to help patients is to avoid causing harm.

Just doing something, with no evidence of benefit, is causing harm.

How many EMS agencies have prehospital therapeutic hypothermia protocols because of a desire to just do something?

I have been criticized for not being a supporter of treatments that do not have evidence of benefit.

Am I a killjoy, desiring bad outcomes?

No.

I understand that treatment that does not have evidence of benefit is almost always going to do more harm than good.

Just do something?

No.

Just demand valid evidence of improved outcomes.

-

Footnotes:

-

[1] Induction of therapeutic hypothermia by paramedics after resuscitation from out-of-hospital ventricular fibrillation cardiac arrest: a randomized controlled trial.
Bernard SA, Smith K, Cameron P, Masci K, Taylor DM, Cooper DJ, Kelly AM, Silvester W; Rapid Infusion of Cold Hartmanns (RICH) Investigators.
Circulation. 2010 Aug 17;122(7):737-42. doi: 10.1161/CIRCULATIONAHA.109.906859. Epub 2010 Aug 2.
PMID: 20679551 [PubMed - indexed for MEDLINE]

Free Full Text from Circulation.

-

Bernard SA, Smith K, Cameron P, Masci K, Taylor DM, Cooper DJ, Kelly AM, Silvester W, & Rapid Infusion of Cold Hartmanns (RICH) Investigators (2010). Induction of therapeutic hypothermia by paramedics after resuscitation from out-of-hospital ventricular fibrillation cardiac arrest: a randomized controlled trial. Circulation, 122 (7), 737-42 PMID: 20679551

.

If We Are Not Competent With Direct Laryngoscopy, We Should Just Say So – Part I

ResearchBlogging.org
 

This study starts out looking good, but there is a huge problem with the design.

If the person intubating felt that he needed to use the video laryngoscope to get the tube, then the patient was not randomize into the study.

How was this paper accepted for publication with such an obviously violation of research methodology?

Did the authors at least track the violations of ethics, so that some analysis of all patients could be attempted?

Maybe this is not really GVL (GlideScope Video Laryngoscope) vs. DL (Direct Laryngoscopy), but a comparison of intubation of the not-so-difficult airway with GVL vs. DL.

What is not-so-difficult? Whatever did not get the doctor to cry, I could not possibly manage that airway safely with a regular laryngoscope!

833 patients would have been randomized, but the person in charge of the airway cried uncle in 210 (just over 25%) of these cases.
 


Image credit.[1]
 

Has airway management really deteriorated to the point where doctors do not feel competent managing 25% of airways without an electronic toy because they are superstitious and believe the toy has magical powers?
 


 

Maybe.

A study could be set up with some sort of objective criteria for excluding the most difficult airways and still be valid, but how do we objectively assess the need for an electric rabbit’s foot?

Did the doctors read their horoscopes and determine that it was a bad day and they needed to use all of their voodoo powers that day?

Did the doctors consult with psychics?

We do not know, because the criteria for superstition are not explained.

This is just a reminder that medicine, and perhaps especially trauma medicine, is still a very superstitious field. It wasn’t that long ago that these patients would have been treated with blood-letting to get rid of the bad humors that prevent healing. Humorous medicine.

Dr. David Newman and Dr. Ashley Shreves describe this in a SMART EM podcast.[2] Dr. Newman corresponded with one of the authors and states that some of the anesthesiologists at Shock Trauma are biased in favor of the video laryngoscope and refuse to use anything else. Were the 210 patients excluded just because some attending anesthesiologists are too biased to learn what works and those anesthesiologists were just throwing a tantrum for all of their patients?

The mythology of I know it works because I’ve seen it work.[3]

Are 25% of the attending anesthesiologists at Shock Trauma too biased to learn?[4]

Or have we improved to the point where only 25% of attending physicians in a specialty are to biased to learn?

To be continued in Part II.

-

Footnotes:

-

Image credit for witch’s hat.

-

[1] Effect of video laryngoscopy on trauma patient survival: a randomized controlled trial.
Yeatts DJ, Dutton RP, Hu PF, Chang YW, Brown CH, Chen H, Grissom TE, Kufera JA, Scalea TM.
J Trauma Acute Care Surg. 2013 Aug;75(2):212-9. doi: 10.1097/TA.0b013e318293103d.
PMID: 23823612 [PubMed - in process]

-

[2] SMART Literature Update
SMART EM podcast
Friday, October 11, 2013
Dr. David Newman and Dr. Ashley Shreves
From about 45:45 to 1:11:00 in the podcast is on this paper.
Podcast page.

-

[3] I’ve Seen It Work and Other Lies
Tue, 21 Jun 2011
Rogue Medic
Article

-

[4] It would be the anesthesiologists managing just over 25% of the intubations, rather than 25% of the anesthesiologists, but no information is provided to clarify how many anesthesiologists that would be.

The result of the bias affects just over 25% of patients.

-

Yeatts DJ, Dutton RP, Hu PF, Chang YW, Brown CH, Chen H, Grissom TE, Kufera JA, & Scalea TM (2013). Effect of video laryngoscopy on trauma patient survival: a randomized controlled trial. The journal of trauma and acute care surgery, 75 (2), 212-9 PMID: 23823612

.

Unreasonable Fear of Hypotension and High-Dose NTG – Part II

ResearchBlogging.org
 

Continuing from Part I to look at the results of the study of high-dose SL (SubLingual) NTG (NiTroGlycerin – GTN GlycerylTriNitrate in Commonwealth countries) by EMS for CHF (Congestive Heart Failure) that Peter Canning wrote about.[1]
 

For CHF, more NTG does not produce more of a drop in blood pressure.
 

If you disagree, provide evidence.

I tend to get anecdotes, with excuses, rather than any kind of evidence.

Anecdotes are often indications that the person telling the anecdote does not understand and is trying to make up for that lack of understanding with bravado.
 


 

Therefore, we will continue to look at the evidence.
 


Click on images to make them larger.
 

You can see that some patients did have large drops in systolic blood pressure with only a double dose of NTG. To clarify, I highlighted the large drops in red below.
 


 

Only six large drops in systolic blood pressure.

Three systolic blood pressures dropped below 100 mmHg.

The expected happened with these dramatic drops in blood pressure and cases of hypotension –

Nobody had any bad outcomes.

The patients recovered without any intervention, such as fluid bolus, epinephrine, or whatever other placebo might be suggested.

Placebo?

A treatment that does not do anything more than doing nothing (benign neglect) is a placebo.

All these patients needed was a paramedic smart enough to use benign neglect.

Anecdotalists give a lot of treatments, because they mistakenly feel that that their intervention improve outcomes. Where is their evidence? In their overactive imaginations.

Those drops with double doses of NTG are scary. How bad was the outcome with triple doses of NTG?
 


 

Again, I highlighted the single big drop – only one – only dropped to about 130 mmHg systolic – in red below.

I added green to highlight the increases in systolic blood pressure after triple dose NTG. There were plenty of increases in systolic blood pressures after double dose NTG, but there were so many increases that it would have made the graph more difficult to read.
 


 

Multiple dose NTG every 5 minutes was clearly safe in this study.

Multiple dose anecdotes about Oh, no! What if . . . ? – continue to be wrong.

Forget the anecdotes.

There is plenty of evidence of safety.

-

Footnotes:

-

[1] Safety of High Dose Nitro in CHF
StreetWatch: Notes of a Paramedic
August 29, 2013
Peter Canning
Article

-

[2] Prehospital High-dose Sublingual Nitroglycerin Rarely Causes Hypotension.
Clemency BM, Thompson JJ, Tundo GN, Lindstrom HA.
Prehosp Disaster Med. 2013 Aug 21:1-4. [Epub ahead of print]
PMID: 23962769 [PubMed - as supplied by publisher]

-

Clemency BM, Thompson JJ, Tundo GN, & Lindstrom HA (2013). Prehospital High-dose Sublingual Nitroglycerin Rarely Causes Hypotension. Prehospital and disaster medicine, 1-4 PMID: 23962769

.

Unreasonable Fear of Hypotension and High-Dose NTG – Part I

ResearchBlogging.org
 

Peter Canning writes about a study of high-dose SL (SubLingual) NTG (NiTroGlycerin – GTN GlycerylTriNitrate in Commonwealth countries) by EMS for CHF (Congestive Heart Failure).[1]

I have some problems with the study.
 


Click on images to make them larger.
 

This is just moderate-dose, not high-dose.

I have had protocols that allow for more aggressive dosing (every 3-5 minutes) going back to 2008.[2]
 


 

I have probably given more triple-dose NTG than was given to the entire intervention group. I have given over 50 SL NTG to just one patient, while they only managed to give a total of 87 tablets in 29 triple doses in the entire study.
 


 

It is good to provide more evidence that multiple dose NTG is safe, but we have had good evidence that prehospital high-dose IV NTG dramatically improves outcomes since the 1990s.

We need more prehospital aggressive IV (IntraVenous) NTG research.
 

Administration of high-dose nitroglycerin is an effective treatment that has been shown to improve the respiratory symptoms associated with ADHF, and decrease the incidence of death due to myocardial infarction and mechanical ventilation, particularly when initiated early.4 – 6 [3]

 

I agree with that.

However, EMS is the best earliest place to start IV NTG.
 

From 1984 through 1991, new guidelines for the use of intravenous nitrates, based on differential treatment according to blood pressure, were in use.

RESULTS:
Overall prehospital mortality rate for APE in all patients was 7.8% (50 of of 640 patients). Mortality after 1984 was significantly lower than before (5.3% versus 13%, P < .01). Nitrates were effective in reducing mortality, even in hypotensive patients. Multivariate analysis showed that outcome was significantly affected by two clinical features (dyspnea and low blood pressure), treatment with nitrates, and calendar period effects (before/after 1984).
[4]

 

Not just hypertensive patients, but also hypotensive patients benefited from EMS IV NTG!

Nitrates were effective in reducing mortality, even in hypotensive patients.

The CHF death rate dropped from 13% all the way down to 5.3%
 


 

Am I complaining that the current study is useless?

Not at all.

There is some excellent information that debunks much of the dogma against multiple-dose NTG.
 


Look at the cases of hypotension – systolic blood pressure less than 100 mm/Hg.

3 cases, but only in the double dose group.

All of the hypotension went away without any treatment.

Zero cases in the triple dose group and the quadruple dose patient did not become hypotensive.
 

For CHF, more NTG does not produce more of a drop in blood pressure.
 

Disagree?

Provide evidence, not anecdotes.

Part II will look at the evidence of safety from this study more closely.

Also see –

Nitroglycerin for Treatment of Acute, Hypertensive Heart Failure – Bolus, Drip or Both?
Wed, 17 Oct 2012

Is a half a bottle of nitro too much for a single dose?
Sun, 18 Nov 2012

NTG and the Hero Medic
Street Watch
November 7, 2012

-

Footnotes:

-

[1] Safety of High Dose Nitro in CHF
StreetWatch: Notes of a Paramedic
August 29, 2013
Peter Canning
Article

-

[2] Congestive Heart Failure
5002– ALS – Adult/Peds
2008, 2011, and 2013 Statewide ALS Protocol
Pennsylvania
Page with link to Full Text Download of Full Protocols in PDF format.

-

[3] Prehospital High-dose Sublingual Nitroglycerin Rarely Causes Hypotension.
Clemency BM, Thompson JJ, Tundo GN, Lindstrom HA.
Prehosp Disaster Med. 2013 Aug 21:1-4. [Epub ahead of print]
PMID: 23962769 [PubMed - as supplied by publisher]

-

[4] Intravenous nitrates in the prehospital management of acute pulmonary edema.
Bertini G, Giglioli C, Biggeri A, Margheri M, Simonetti I, Sica ML, Russo L, Gensini G.
Ann Emerg Med. 1997 Oct;30(4):493-9.
PMID: 9326864 [PubMed - indexed for MEDLINE]

-

Clemency BM, Thompson JJ, Tundo GN, & Lindstrom HA (2013). Prehospital High-dose Sublingual Nitroglycerin Rarely Causes Hypotension. Prehospital and disaster medicine, 1-4 PMID: 23962769

-

Bertini G, Giglioli C, Biggeri A, Margheri M, Simonetti I, Sica ML, Russo L, & Gensini G (1997). Intravenous nitrates in the prehospital management of acute pulmonary edema. Annals of emergency medicine, 30 (4), 493-9 PMID: 9326864

.

Factors associated with failed intubation attempts in the ED – Difficult Airway

ResearchBlogging.org
 

As with any procedure, each attempt at intubation increases the chance of harm to the patient.

What can we do to minimize the possibility of making more than one attempt at intubation?
 

The aim of this study was to identify factors associated with successful second and third attempts in adults following a failed first intubation attempt to support an effective rescue attempts strategy in the ED.[1]

 

Click on images to make them larger.
 

The success rate for each attempt was about 80% for the first, second, and third attempts. Several factors seem to have influenced that success rate, but the most important appears to have been the presence of a difficult airway.
 

The 6 academic EDs were equipped with core airway devices and drugs, one or more extraglottic devices, one or more video laryngoscopes and fiberscopes, RSI drugs, and one or more cricothyrotomy sets or kits.[1]

 

All intubations were supervised by a senior physician, so they should be well prepared for difficult airways.
 

A difficult airway was defined as a case in which the first intubator anticipated the difficult airway considering 3 dimensions of difficulty: difficult laryngoscopy and intubation, difficult bag-mask ventilation, and difficult cricothyrotomy.[1]

 

In the discussion, the authors suggest that they may have come up with higher rates of difficult airways for the first intubation attempt due to using three criteria to identify difficult airways.

This should not suggest that their conclusions about difficult airways are weakened. The opposite is more. They were less likely to miss a difficult airway. Difficult bag-mask ventilation may not be predictive of a difficult airway, but the increasing proportion of difficult airways among the failed intubations suggests that these airways were difficult.
 


 

Perhaps if we view the difficult airways as a proportion of the successes and failures of each intubation attempt, it will make things more clear.
 


 

Only 26.3% of first intubation attempt failures, but 36.5% of second intubation attempt failures, and increasing dramatically to 64% of third intubation attempt failures.

This does raise the question of why 36% of third intubation attempt failures were not considered difficult intubations?

Were they only going by the initial assessment of difficult intubation?

Shouldn’t we be reevaluating as we get further information as the Reverend Thomas Bayes advises?[2]

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Footnotes:

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[1] Factors associated with successful second and third intubation attempts in the ED.
Kim JH, Kim YM, Choi HJ, Je SM, Kim E; on behalf of the Korean Emergency Airway Management Registry (KEAMR) Investigators.
Am J Emerg Med. 2013 Jul 29. doi:pii: S0735-6757(13)00395-1. 10.1016/j.ajem.2013.06.018. [Epub ahead of print]
PMID: 23906622 [PubMed - as supplied by publisher]

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[2] Bayesian inference
Wikipedia
Article

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Kim JH, Kim YM, Choi HJ, Je SM, Kim E, & on behalf of the Korean Emergency Airway Management Registry (KEAMR) Investigators (2013). Factors associated with successful second and third intubation attempts in the ED. The American journal of emergency medicine PMID: 23906622

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