Friday, September 5, 2014

HOT salted...plastic?

The debut post for Critical Caring, “Hypertonic Saline: Worth its salt?”, was well if not widely received, but it did turn a few heads. Hyperosmolar therapy (HOT) was concurrently the subject of the Emergency Medicine EMS journal club meeting our trauma center, and the response was favorable enough among the EM physicians (our transport medical director one of them) to write a protocol for our air/ground CCT service to guide administration of hypertonic saline (HTS) to patients with significant intracranial hypertension. 
In search of inspiration, I asked Dr. Bill Hinckley from University of Cincinnati Air Care (tweeting as @UCAirCareDoc) for his HOT protocol1, and he graciously agreed.  While reading his protocol, I came across something I hadn’t considered:


It had not honestly occurred to me that a patient could have such severe intracranial hypertension as to warrant HOT but still not meet clinical criteria for intubation.  Though I had never transported or seen a patient who fit this description, I conceded there are many things I haven’t seen and don’t know and gladly counted this among them.  So I included this box in the first draft of our protocol:







to which the medical director replied  I wonder about managing intracranial hypertension…in a patient who is not intubated.  Makes sense. I probably should have asked that question myself.

He also said “It might make more sense to make intubation a requirement – not as a means of management, but as a marker of severity.”  Again, incredibly sound logic.  If someone is sick enough, by the criteria (posturing, hypertensive, unilaterally blown pupil, seizure, coma), to need HOT, would they not also need definitive airway control?  This has been my own experience as well as that of many intensivists I had polled on the issue before, leaving me to wonder how often do we manage intracranial hypertension WITHOUT an advanced airway? To begin, I tossed the question to Twitter.

Twitter rarely disappoints.

Dr. Hinckley answered “rarely” and put the questions to a few of his colleagues and followers.  Here is some of the discussion:

Dr. Chris Zammit (@cgzammit) said “I advocate for HOT if there is neurodeterioration (GCS drop by 2 or more points)”  This seems sounds, even if the GCS D doesn’t meet the magic threshold of 8 to intubate (which, by the way, I’ve always though was a little suspect).  It has been my experience that GCS in the setting of significant brain insult doesn’t spontaneously improve, but rather declines over time, seemingly falling faster the further it declines. So even if the patient goes from GCS 15 to 13 between neruo assessments, it is conceivable that 11 and then 9 are fast approaching.  

This line of thought was echoed by Wendy Chang (@EM_NCC), a neurointensivist who adds that HOT in non-intubated patients is “not common, since those who need HOT are critical and likely need ETT but possible as HOT may reduce ICP/reverse herniation and pt would not need ETT.”  She and others (Brian Burns, @HawkmoonHEMS; Taylor Zhou, @canibagthat) mostly agree that these are critical patients who are not only comatose enough to warrant intubation, but also need to have oxygenation and ventilation strictly controlled to prevent hypoxia and maintain normal ventilation or provide mild hyperventilation in the case of acute herniation. 

A few things worth remembering about HOT:
  • · Both 3% Saline and Mannitol can be given safely via peripheral IV, though mannitol requires a filter.2,3
  •   They can both be given IO, but make sure your access is patent prior to bolus.4
  • · Mannitol should be avoided in the profoundly hypotensive or poorly resuscitated patient due to massive osmotic shift and diuresis.5
  • ·  HOT therapy doesn’t take place in a vacuum.  Sedation, analgesia, hemodynamic support, oxygenation and ventilatory regulation are all crucial to good outcomes in these patients.6

HOT is rare intervention in our service, and instituted almost universally in the intubated patient, so our protocol will read that way, at least for now. 

Thanks for reading Critical Caring.  Feel free to comment here or on twitter, @Crit_Care_Excel

References
  1. Hinckley B. Management of Intracranial Hemorrhage (SAH, ICH In: University of Cincinnati UC Health AirCare Policy #CLIN24 January 2013
  2. Mannitol injection, USP. (2014, July 2014). Retrieved from hospira.com: www.hsopira.com/products_and_service/drugs/mannitol
  3. Luu, J. (n.d.). Three percent saline administration during pediatric critical care transport. Pediatric Emergency Care, 1113-1117.
  4. Intraosseous(IO) Vascular Access and the EZ-IO Frequently asked questions. (2014, july 25). Retrieved from vitaid.com: www.vitaid.com/files
  5. Managment of patients with severe head trauma. (2012). Joint Theater trauma system clinical practice guidelines. United States.
  6. Prehospital TBI-Beyond the “Code”. Taming the SRU website. http://www.tamingthesru.com/blog/acmc/prehospital-tbi-beyond-the-code?q=tbi Published 5/20/2014. Accessed 9/5/14

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