Journal Club - February 2, 2015

• What:  Weekly Journal Club
• Where:  MONOC Education Building, 1415 Wyckoff Road, Ground Floor, Wall Township, NJ
• When:  Monday, February 2, 2015 at 10:00 am

• Out-of-hospital spinal immobilization:  Its effect on neurologic injury.  http://www.ncbi.nlm.nih.gov/pubmed/9523928.  An oldie but a goodie.
• Inaccurate treatment decisions of automated external defibrillators used by emergency medical services personnel:  Incidence, cause and impact on outcome.  http://www.ncbi.nlm.nih.gov/pubmed/25556589.  Somewhat surprising analysis of AED error rates.
• Is Copeptin level Associated with 1-year Mortality After Out-of-Hospital Cardiac Arrest?  Insights From the Paris Registry.  http://www.ncbi.nlm.nih.gov/pubmed/25599466.  How well can we prognosticate those we get pulses back on?
• Endotracheal Intubation in Patients Treated for Prehospital Status Epilepticus.  http://www.ncbi.nlm.nih.gov/pubmed/25623785.  More debate on whether pre-hospital intubation helps or harms. 
• Should suspected cervical spinal cord injury be immobilised?: A systematic review.  http://www.ncbi.nlm.nih.gov/pubmed/25624270.  A nice systematic review on the evidence of cervical spine immobilization.

Live-tweeting of the journal club @CCareAnywhere.  #EMSJC

More Than Just Shock Value?

*Note - this discussion is only pertinent to modern biphasic defibrillators with self adhesive electrodes applied only anterior/posterior or anterior/lateral, with the compression provider wearing two pairs of gloves (double-gloving), with a maximum defibrillation energy of 360J.*

We have all heard the chant, “I’m clear, you’re clear, we’re all clear,” prior to a provider double, triple, sometimes quadruple checking him or herself before pushing that magic red button with the white lightning bolt - “shock”!  Recent literature has spurred quite the discussion on hands-on defibrillation (HOD) - CPR where compressions continue throughout the defibrillation - as it is widely known that interruptions in chest compressions lead to poor patient outcomes and are all too common, for example, during intubation, providing ventilations, AED analyzing, charging, and during defibrillation shocks.  This pearl is meant to provide a very brief explanation of what your risks might be, what protection devices you might use, anecdotal and published accounts on HOD, and suggestions for your clinical practice.

There are numerous factors in regards to energy and the effect it may have on the provider during HOD.  Energy is the product of voltage, current and time.  Neither factors, independently, are sufficient in inducing damaging effects.  For example, several thousand volts are experienced during static electricity, although the current is very low.  Current is determined by the resistance between the electrodes of the defibrillator, the electrode gel, the gel-skin contact, and the tissue resistance.  Glove integrity, skin moisture and the actual current pathway will determine the amount of escape current.  Biphasic defibrillators provide voltages up to approximately 2200 V over approximately 15-20 msec.  The maximum permissible leakage current, per the International Commission on Non-Ionizing Radiation Protection is 1mA; the threshold for perception is 2.5-4.0 mA; and pain is experienced at 6-10 mA.²  Sullivan and Chapman studied the voltage-current curves for gloves.  They note the international safety standard on 1mA and explain that at this level, it would take 1-3 seconds of current flow to induce VF in <5% of the population.  While defibrillation shocks are usually less than 20 msec, even if the pulse is timed appropriately in the rescuer’s cardiac cycle, as much as 500 mA would be required to induce VF.¹ For reference, the current exposure from a home body fat monitoring scale is 500 uA.

In one of the most exciting studies, Lloyd et al measured current between “rescuers” and patients undergoing cardioversion at up to 360 J and found the highest current leak measured was 907 uA,⁴ with no “rescuers” experiencing a “shock.”  Neumann et al found HOD was safely performed on pigs by rescuers, HOD shortened pauses during CPR, and it more quickly restored coronary perfusion pressure.⁴  Kurz and Sawyer, in their letter to the editor of Resuscitation, advocate eliminating effects of no-flow time, perhaps by using HOD.⁷ Dr. Scott Weingart writes that in the 4 years that he and his colleagues have been performing HOD, there have been no rescuer complications, although occasional perceptions of tingling have been reported.  He himself reported arm soreness after 3 shocks, all at 360 J with the electrode pads notably in the anterior/anterior position.

In opposition, Lemkin et al derive an equation called the rescuer-received dose, to try to better qualify defibrillation risk.  Noting that energy values greater than 1 J reportedly can cause VF, they deem HOD unsafe as values above 1 J were calculated in their cadaver study, though effects of gloves were not accounted for.  Two studies from the UK found that medical examination gloves do not provide rescuer safety and even demonstrate further glove breakdown of the gloves worn by rescuers who perform compressions.  According to Sullivan and Chapman, HOD with medical examination gloves will produce no sensation at all unless the gloves completely break down.¹  

Although there are no reported fatalities or serious consequences to rescuers performing HOD under ideal conditions - using a biphasic defibrillator with electrodes placed appropriately, with rescuers double gloved - we should take note that any change to a safety protocol should not be undertaken without ensuring rescuers' safety.  I have personally performed HOD, as have my colleagues in the emergency department.  While none of us have experienced any detrimental consequences or even the reported tingling, considering the literature, perhaps we should currently hold off on changing our protocols to mandate hands-on defibrillation.  Protocols that need to be changed or followed are as follows:

• High quality CPR remains of utmost importance.  Set a metronome at 100 beats per minute and compress the chest to 1.8” (or as close to it as possible) every time.
• Have no interruptions in chest compressions - not for intubation, not for starting an IV, not for inserting a central line, not for transporting, and not for charging the defibrillator!
                

The use of HOD needs to reflect your clinical decision made in the best interest of you, your co-rescuers, and your patient.  If you chose to do so, please double-glove, please place the electrodes anterior/posterior, and communicate your practice to your colleagues.    

References

1.  Sullivan JL, Chapman FW. Will medical examination gloves protect rescuers from defibrillation voltages during hands-on defibrillation? Resuscitation. 2012 Dec;83(12):1467-72. doi: 10.1016/j.resuscitation 2012.07.031. Epub 2012 Aug 25. PubMed PMID: 22925991

2.  Petley GW, Cotton AM, Deakin CD. Hands-on defibrillation: theoretical and practical aspects of patient and rescuer safety. Resuscitation. 2012 May;83(5):551-6. doi: 10.1016/j.resuscitation.2011.11.005. Epub 2011 Nov 15. Review. PubMed PMID: 22094984.

3.  Sullivan JL. Letter by Sullivan regarding article, "Hands-on defibrillation: an analysis of electrical current flow through rescuers in direct contact with patients during biphasic external defibrillation". Circulation. 2008 Dec 2;118(23):e712; author reply e713. doi: 10.1161/CIRCULATION AHA.108.803718. PubMed

PMID: 19047587.

4.  Lloyd MS, Heeke B, Walter PF, Langberg JJ. Hands-on defibrillation: an analysis of electrical current flow through rescuers in direct contact with patients during biphasic external defibrillation. Circulation. 2008 May 13;117(19):2510-4. doi: 10.1161/CIRCULATION AHA.107.763011. Epub 2008 May 5. PubMed PMID: 18458166.

5.  A note of caution on the performance of hands-on biphasic defibrillation. Weingart SD. Resuscitation. 2013 Mar;84(3):e53. doi: 10.1016/j.resuscitation.2012.12.014. Epub 2012 Dec 22. PMID: 23266533

6. Lemkin DL, Witting MD, Allison MG, Farzad A, Bond MC, Lemkin MA. Electrical exposure risk associated with hands-on defibrillation. Resuscitation. 2014 Oct;85(10):1330-6. doi: 10.1016/j.resuscitation.2014.06.023. Epub 2014 Jun 30. PubMed PMID: 24992873.

7.  Petley GW, Deakin CD. Do clinical examination gloves provide adequate electrical insulation for safe hands-on defibrillation? II: Material integrity following exposure to defibrillation waveforms. Resuscitation. 2013 Jul;84(7):900-3. doi: 10.1016/j.resuscitation.2013.03.012. Epub 2013 Mar 16. PubMed PMID: 23507465.

8.  Deakin CD, Lee-Shrewsbury V, Hogg K, Petley GW. Do clinical examination gloves provide adequate electrical insulation for safe hands-on defibrillation? I: Resistive properties of nitrile gloves. Resuscitation. 2013 Jul;84(7):895-9. doi: 10.1016/j.resuscitation.2013.03.011. Epub 2013 Mar 16. PubMed PMID: 23507464.

Did you get the orthostatics yet?

A 70 y/o male presents from a nursing facility with symptoms of weakness after 2 days of diarrhea.  He states it has been watery and occurring 4-5 times per day.  His heart rate is 80 bpm and regular, BP 130/70, respirations of 16, skin warm and dry. He appears well but shows a little general weakness overall.  He knows he takes medications for his blood pressure; however, he is not sure of the name.

Q: Would you get orthostatic vital signs on this patient to assess for volume loss?

Orthostatic vital signs have been used to assess for volume loss by measuring the body’s response to positional change.  Upon standing from a supine position, vasoconstriction and changes in heart rate help to maintain perfusion.  It is thought that when a person is hypovolemic this system fails and blood pools in the lower extremities causing a drop in blood pressure and/or an increase in heart rate.   Symptoms of orthostatic hypotension are lightheadedness, dizziness, blurred vision, weakness, fatigue, cognitive impairment, nausea, palpitations, tremulousness, headache, and syncope.  Orthostatic vital signs are considered positive when there is a drop in systolic blood pressure of ≥ 20 mmHg, drop in diastolic blood pressure of ≥ 10 mmHg, or heart rate increase of ≥ 30 beats per minute within 3 minutes of standing from a supine position.¹

The utility of orthostatic vital signs came into question over 20 years ago.  A study in 1990 looked at orthostatic vitals in 132 self-proclaimed euvolemic patients aged 18-80 years old (mean 34.1 +/- 13.6 years).  Of these patients 43% tested positive.  The study concluded that normal patients may present with orthostatic vitals given the current criteria.²

In 1997, a study examined orthostatics in 911 non-acutely ill patients aged greater than 60 from 45 different nursing homes.  To be included in the study, patients had to be able to stand for at least one minute.  The study found that over 50% of patients had orthostatic changes at baseline and it was most prevalent in the morning when patients first rise.³

Besides the elderly, orthostatic vitals were examined in adolescents as well.  307 healthy high school students aged 15-17 were checked for orthostatic vitals.  The study found pulse changes within the population to be 61% sensitive and 56% specific.  They also found orthostatic blood pressure changes to be within the adult range for 98% of adolescents, and a third of participants experienced orthostatic symptoms.  The study concluded the orthostatic heart rate criterion to be likely inappropriate for adolescents.⁴  Another study examining blood pressure changes in 23 healthy adolescents concluded transient orthostatic hypotension is common in their population.⁵

In addition to examining orthostatics in the non-acutely ill and adolescents, they were also studied in patients with known blood volume loss.  A study in 1992 examined 100 blood donors aged 19-83 years old and 100 senior center volunteers aged 55-94. The blood donors all gave 450 mL of blood.  Orthostatics had no clinical difference between ages.  Furthermore, a pulse rise >20 bpm or a diastolic BP drop > 10 mmHg had a specificity of 17%, sensitivity of 98%.  Systolic changes yielded no better.⁶ A similar study from 1994 looked at orthostatics in blood donation of 450 mL between two age groups, patients <65 and patients 65 or older.  These were healthy volunteers at baseline prior to blood donation.   A pulse change >20 bpm was found to have a sensitivity of 43% and a specificity of 94% in patients less than 65 years old.  In the age 65 and older group, pulse change was found to have a sensitivity of 25% and a sensitivity of 100%.  When they looked at blood pressure, they found it was worse than the flip of a coin.⁷

Besides blood volume loss, fluid volume loss and orthostatics were also studied. A study of 23 pregnant women with hyperemesis gravidarum studied the sensitivity of orthostatics in pre and post rehydration of 6 liters of lactated Ringer’s solution.  The study found that orthostatic changes lack sufficient sensitivity to be effectively used as quantitative screening tests for dehydration.⁸

In summary, the review above shows that using orthostatic vital signs alone to determine volume loss is highly unreliable.  Many patients can test positive for orthostatic signs even when asymptomatic.  We would never want to utilize a test that is so sensitive yet essentially with minimal specificity.  This would then cause the healthcare provider to act on all of the “positive” results by assuming the patient is hypovolemic. To make matters worse, the proportion of patients on beta blockers causing a blunting of the testing would make this even more unreliable than it already is.  When patients were known to have volume loss, orthostatic vitals still lacked a sufficient sensitivity to be deemed an effective test.  Looking for orthostatic clinical signs, not the numbers, is a far more reliable means to assess volume loss.  If the patient stands up and feels either lightheaded or passes out, this is sufficient enough to determine significant hypovolemia.  

References

1.         Naccarato M, Leviner S, Proehl J, et al. Emergency Nursing Resource: orthostatic vital signs. Journal of emergency nursing: JEN : official publication of the Emergency Department Nurses Association. Sep 2012;38(5):447-453.

2.         Koziol-McLain J, Lowenstein SR, Fuller B. Orthostatic vital signs in emergency department patients. Annals of emergency medicine. Jun 1991;20(6):606-610.

3.         Ooi WL, Barrett S, Hossain M, Kelley-Gagnon M, Lipsitz LA. Patterns of orthostatic blood pressure change and their clinical correlates in a frail, elderly population. Jama. Apr 23-30 1997;277(16):1299-1304.

4.         Skinner JE, Driscoll SW, Porter CB, et al. Orthostatic heart rate and blood pressure in adolescents: reference ranges. Journal of child neurology. Oct 2010;25(10):1210-1215.

5.         Stewart JM. Transient orthostatic hypotension is common in adolescents. The Journal of pediatrics. Apr 2002;140(4):418-424.

6.         Baraff LJ, Schriger DL. Orthostatic vital signs: variation with age, specificity, and sensitivity in detecting a 450-mL blood loss. The American journal of emergency medicine. Mar 1992;10(2):99-103.

7.         Witting MD, Wears RL, Li S. Defining the positive tilt test: a study of healthy adults with moderate acute blood loss. Annals of emergency medicine. Jun 1994;23(6):1320-1323.

8.         Johnson DR, Douglas D, Hauswald M, Tandberg D. Dehydration and orthostatic vital signs in women with hyperemesis gravidarum. Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. Aug 1995;2(8):692-697.

Things We Can Do Better in 2015!

Here's my list of the top 20 things we can do better in 2015 based on what we learned in 2014 (or even before).

1. High-flow nasal cannula (HFNC), at least 15 Lpm, on all patients undergoing intubation or who might need intubation.
2. PEEP valve on every BVM.
3. No longboards for ANY patient.  Continue to use spinal precautions as appropriate, but that doesn't mean you need a long spinal board.
4. Ketamine, followed by ketamine, rounded out by MORE KETAMINE for RSI induction.
5. No Versed (midazolam) for intubation or post-intubation.
6. No interruptions in compressions for any reason.  Your survival decreases by 7% for every five seconds without compressions. We should be working on improved CPR and "see-through CPR" monitor technology, and don't you dare hold compressions while the monitor is charging!
7. Tranexamic acid (TXA) for all hemodynamically unstable trauma patients.
8. Let the fentanyl flow for intubations, especially after intubation. Pre-intubation benefits in head trauma.
9. More intranasal medications.
10. Use D25 instead of D50 when available.
11. Treat septic nursing home patients like the real emergencies they are.  IV fluids with 30-40 cc/kg bolus.  IV access at a minimum to speed up the time to first antibiotics.
12. Agitated/emotionally-disturbed patients should be recognized as real emergencies as well.  These may be excited delirium.  Treat with ketamine IM; doses as high as 4 mg/kg IM shown to be safe.
13. No etomidate for sepsis or hypotensive patients.
14. Push dose epinephrine for peri-intubation hypotension.
15. Rotate people doing compressions at least every 3 minutes.
16. Stop using BVMs on patients if RR is at least 4 or SPO2 is at least 94%. Instead, use high-flow nasal cannula with a nonrebreather on top.
17. Every BLS should have a pulse oximeter.  They are very affordable these days.
18. Use a metronome for every cardiac arrest!  If your monitor doesn't have one, download an app.
19. No more nitroglycerin paste.
20. Starting dosage of Zofran (ondansetron) for adults should be 8 mg.

Journal Club - January 5, 2015

• What:  Weekly Journal Club
• Where:  MONOC Education Building, 1415 Wyckoff Road, Ground Floor, Wall Township, NJ
• When:  Monday, January 5, 2015 at 10:00 am

• Traumatic intra-abdominal hemorrhage control:  Has current technology tipped the balance toward a role for prehospital intervention?  http://www.ncbi.nlm.nih.gov/pubmed/25539217.  Do we have the ability to control intra-abdominal hemorrhage in the prehospital environment?  Does it matter with the new use of TXA?
• Apneic Oxygenation Was Associated With Decreased Desaturation Rates During Rapid Sequence Intubation by an Australian Helicopter Emergency Medicine Service.  http://www.ncbi.nlm.nih.gov/pubmed/25536868.  More evidence that this should be done on every patient needing intubation.
• EMS Patients and Walk-In Patients Presenting With Severe Sepsis:  Differences in Management and Outcome.  http://www.ncbi.nlm.nih.gov/pubmed/25502152.  We reviewed an article earlier this year showing improved outcomes in septic patients when brought by ambulance.  Does this study show the same thing?  Come to journal club and find out!
• AWARE - AWAreness during REsuscitation - A prospective study.  http://www.ncbi.nlm.nih.gov/pubmed/25301715.  As we improve our high-quality CPR, we are hearing more anecdotal reports of patients having consciousness during compressions.  Is this real life?!

Live-tweeting of the journal club @CCareAnywhere.  #EMSJC