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{Noninvasive ventilation}

Q: Does noninvasive positive pressure ventilation for CHF save lives?
a: Yes!
by Ashley E. Shreves, MD

NNT=8
For every eight CHF patients you treat with NIPPV, one death is prevented

NNH=18
Side effects were minor, and the most common was gastric distension, then skin damage (20) and mask discomfort (30)

Color Code
              
Green: More benefit than harm

Take Home Message: NIPPV for CHF appears to save lives, though the data only includes roughly 1000 subjects from both ICUs and EDs.

Details: Noninvasive positive pressure ventilation (NIPPV) has been theorized to offer the advantages of respiratory assistance and improved gas exchange without the disadvantages associated with sedation, paralysis, and endotracheal intubation. This Cochrane Review includes 21 trials (n = 1071) in both the ICU and emergency department settings. Some compared bilevel positive airway pressure (BIPAP) devices, or continuous devices (CPAP) to standard therapy, while others compared the two. There was no advantage to one over the other. Exclusion criteria were consistent across studies, and typically included immediate need for intubation, altered sensorium, or hypotension. Pharmacologic treatments varied however, with some subjects receiving morphine, dopamine, digoxin, or diazepam. There was a range in the settings for each method. With BIPAP inspiratory pressures ranged from 9 to 17 (cm H2O) and expiratory from 4 to 11. During CPAP positive end-expiratory pressures levels ranged between 7.5 and 11.
In aggregate, the studies showed clinically important benefits.

Caveats: Unfortunately, only 8 of 21 trials reported adverse events. Surprisingly, pulmonary aspiration, pneumothorax, asphyxia, and claustrophobia were not detected, but less dangerous adverse events were, specifically skin damage (5%), gastric distention (6%) and mask discomfort (3%).

Data source: Vital FMR, Saconato H, Ladeira MT, et al. Non-invasive positive pressure ventilation (CPAP or bilevel NPPV) for cardiogenic pulmonary edema. Cochrane Database of Systematic Reviews 2008, Issue 3. Art. No.: CD005351. DOI: 10.1002/14651858.CD005351.pub2.

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The NNT Explained

The NNT offers a measurement of the impact of a medicine or therapy by estimating the number of patients that need to be treated in order to have an impact on one patient. The concept is statistical, but intuitive. After all, we know that not everyone is helped by a medicine or intervention—some benefit, some are harmed, and some are unaffected. The NNT and the NNH (number-needed-to-harm) tell us how many.

TheNNT.com is a project designed to make these estimates available for decisions at the bedside, and in conversations with patients. There’s a lot of data out there, TheNNT.com is just a place where it’s easy to find, and easy to use.
-David Newman, MD
Editor-in-Chief, TheNNT.com

 *******************

 

{The ACLS Algorithms}

Q: Do intravenous drugs, as recommended by ACLS algorithms, improve survival?
a: Excellent studies say NO
by David H. Newman, MD

NNT
For neurologically intact survival, there is NO BENEFIT.

NNH
No medical harms were identified


Color Code
                
Red: This intervention is proven to be of no benefit.

Take Home Message: Using the ACLS-recommended drug algorithm does not improve survival from cardiac arrest, though it does lead to more ICU admissions

Details: Sudden cardiac arrest (SCA) is common and Advanced Cardiac Life Support (ACLS) is a set of recommendations by the American Heart Association that is used throughout the world for this condition. While rapid defibrillation appears highly effective for SCA, the role of intravenous drugs has long been unclear. Two high quality trials test the AHA recommendations. The first used historical controls during the ‘phase-in’ of an ACLS system (being added to a rapid-defibrillation-and-CPR-only system). ACLS did not improve survival. The second study randomized 851 SCA patients to treatment with or without intravenous access, using ACLS drug algorithms only in those with IV access. There was no difference between groups in mortality.

The harms and costs of ACLS are not typically visible in such studies, however because patients are pulseless (dead) at the moment of enrollment, any intervention that does not produce an improvement may represent a lost opportunity to use an alternative approach.  In addition, in both studies ACLS drugs increased ICU admissions by 5 to 10%.

Caveats: One of the above studies used a before/after design, and the second is in a single Norwegian emergency medical services setting. Despite being high quality evidence the data are limited and the external validity is unclear. In addition, these trials refer to nontraumatic out-of-hospital cardiac arrest. In-hospital trials have not yet been done, although observational studies have also suggested possible harms from ACLS medications.

Data source:  Olasveengen, TM, Sunde K, Brunborg C, Thowsen J, et al. Intravenous Drug Administration During Out-of-Hospital Cardiac Arrest: A Randomized Trial. JAMA. 2009; 302(20):2222-2229.

IG Stiell, GA Wells, B Field, Advanced cardiac life support in out-of-hospital cardiac arrest..N Engl J Med 2004;351:647-656

 

 

 

 

Comments   

# Dr.Patricia 2012-09-26 12:36
Finally. Now can we stop the nonsense of ACLS every 2 years? It's such a scam.
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