Category Archives: PHARM

Prehospital and Retrieval Medicine

American airway management in the field

I often wonder why my US colleagues are so vehemently opposed to out-of-hospital tracheal intubation. This paper provides a clue. I would love it if any EMS providers out there could comment, as I find these results staggering.
The authors comment that the data set “contains data on over 4.3 million EMS events from 16 states (Alabama, Colorado, Florida, Hawaii, Iowa, Maine, Minnesota, Missouri, North Carolina, North Dakota, Nebraska, New Hampshire, New Jersey, New Mexico, Nevada, and Oklahoma) for the one-year period January 1, 2008–December 31, 2008. These states were the first to participate in the NEMSIS project. There are no estimates of the numbers of EMS agencies or EMS responses that are not included in NEMSIS. Hawaii, New Jersey, New Mexico and Oklahoma provided only partial data for the study period because of their implementation of NEMSIS during 2008.

OBJECTIVE: Prior studies describe airway management by single EMS agencies, regions or states. We sought to characterize out-of-hospital airway management interventions, outcomes and complications across the United States.
 
METHODS: Using the 2008 National Emergency Medical Services Information System (NEMSIS) Public-Release Data Set containing data from 16 states, we identified patients receiving advanced airway management, including endotracheal intubation (ETI), alternate airways (Combitube, Laryngeal Mask Airway (LMA), King LT, Esophageal-Obturator Airway (EOA)), and cricothyroidotomy (needle and open). We examined airway management success and complications in the full cohort and in key subsets (cardiac arrest, non-arrest medical, non-arrest injury, children <10 and 10-19 years, rapid-sequence intubation (RSI), population setting and US census region). We analyzed the data using descriptive statistics.
RESULTS: Among 4,383,768 EMS activations, there were 10,356 ETI, 2246 alternate airways, and 88 cricothyroidotomies. ETI success rates were: overall 6482/8418 (77.0%; 95% CI: 76.1-77.9%), cardiac arrest 3494/4482 (78.0%), non-arrest medical 616/846 (72.8%), non-arrest injury 417/505 (82.6%), children <10 years 295/397 (74.3%), children 10-19 years 228/289 (78.9%), adult 5829/7552 (77.2%), and rapid-sequence intubation 289/355 (81.4%). ETI success was success was lowest in the South US census region. Alternate airway success was 1564/1794 (87.2%). Major complications included: bleeding 84 (7.0 per 1000 interventions), vomiting 80 (6.7 per 1000) and esophageal intubation 12 (1.0 per 1000).
CONCLUSIONS: In this study characterizing out-of-hospital airway management across the United States, we observed low out-of-hospital ETI success rates. These data may guide national efforts to improve the quality of out-of-hospital airway management.

Out-of-hospital airway management in the United States
Resuscitation. 2011 Apr;82(4):378-85

FAST 1 success rates in the field

Three quarters of attempts to place the FAST 1 sternal intraosseous device were successful…

Introduction: Access to the vascular system of the critically ill or injured adult patient is essential for resuscitation. Whether due to trauma or disease, vascular collapse may delay or preclude even experienced medical providers from obtaining standard intravenous (IV) access. Access to the highly vascular intramedullary space of long bones provides a direct link to central circulation. The sternum is a thin bone easily identified by external landmarks that contains well-vascularized marrow. The intraosseous (IO) route rapidly and reliably delivers fluids, blood products, and medications. Resuscitation fluids administered by IV or IO achieve similar transit times to central circulation. The FAST-1 Intraosseous Infusion System is the first FDA-approved mechanical sternal IO device. The objectives of this study were to: (1) determine the success rate of FAST-1 sternal IO device deployment in the prehospital setting; (2) compare the time of successful sternal IO device placement to published data regarding time to IV access; and (3) describe immediate complications of sternal IO use.
Methods: All paramedics in the City of Portsmouth, Virginia were trained to correctly deploy the FAST-1 sternal IO device during a mandatory education session with the study investigators. The study subjects were critically ill or injured adult patients in cardiac arrest treated by paramedics during a one-year period. When a patient was identified as meeting study criteria, the paramedic initiated standard protocols; the FAST-1 sternal IO was substituted for the peripheral IV to establish vascular access. Time to deployment was measured and successful placement was defined as insertion of the needle, with subsequent aspiration and fluid flow without infiltration.
Results: Over the one-year period, paramedics attempted 41 FAST-1 insertions in the pre-hospital setting. Thirty (73%) of these were placed successfully. The mean time to successful placement was 67 seconds for 28 attempts; three of the 31 insertions did not have times recorded by the paramedic. Paramedics listed the problems with FAST-1 insertion, including: (1) difficulty with adhesive after device placement (3 events); (2) failure of needles to retract and operator had to pull the device out of the skin (2 events); and (3) slow flow (1 event). Emergency department physicians noted two events of minor bleeding around the site of device placement.
Conclusion: This is the first study to prospectively evaluate the prehospital use of the FAST-1 sternal IO as a first-line device to obtain vascular access in the critically ill or injured patient. The FAST-1 sternal IO device can be a valuable tool in the paramedic arsenal for the treatment of the critically ill or injured patient. The device may be of particular interest to specialty disaster teams that deploy in austere environments.

Evaluation of success rate and access time for an adult sternal intraosseous device deployed in the prehospital setting
Prehosp Disaster Med 2011;26(2):127–129

Intubation checklist

Perhaps you’ve read the blog post and heard the podcast about the excellent NAP4 airway audit…..now you can start putting the learning points into action with the intubation checklist, developed by the regional trainee-led collaborative ‘RTIC Severn’. Thanks to Dr Tim Bowles for the link:

I’ve used an RSI checklist for both in-and-out of hospital intubations for the last seven years. The beauty of this one is the potential for it to become a standard within and between hospitals, so wherever you work the team will be on the same page when preparing for intubation.
Further details are at http://saferintubation.com

Status epilepticus review

A review on status epilepticus, differentiating complex partial status from generalised convulsive status:

PURPOSE OF REVIEW: Status epilepticus is one of the most common emergencies in neurology, and every third patient does not respond to adequate first-line treatment. Refractory status epilepticus may be associated with increased morbidity and mortality, and new treatment options are urgently required. This review critically discusses recently published data regarding the role of ‘new’ antiepileptic drugs, the efficacy and safety of anesthetic agents, and the overall clinical outcome that is an integral part of treatment decisions.
RECENT FINDINGS: In complex partial status epilepticus, levetiracetam may be administered after failure of first-line and/or second-line agents. Lacosamide may be an interesting new adjunct, but reliable data are pending. In the treatment of refractory generalized convulsive status epilepticus, propofol seems to be as efficient as barbiturates. The latter are associated with prolonged ventilation times due to redistribution kinetics, whereas the former bears the risk of propofol infusion syndrome if administered continuously. Even after prolonged treatment with anesthetics over weeks, survival with satisfactory functional outcome is possible.
SUMMARY: Unambiguous recommendations regarding treatment strategies for refractory status epilepticus are limited by a lack of reliable data. Therefore, randomized controlled trials or at least prospective observational studies based on strict protocols incorporating long-term outcome data are urgently required.

Treatment strategies for refractory status epilepticus
Curr Opin Crit Care. 2011 Apr;17(2):94-100

STEMI criteria vary with age and sex

On reading through the 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science – Part 10: Acute Coronary Syndromes, I found a reminder that the ECG criteria for diagnosing ST-elevation myocardial infarction (STEMI) vary according to age and sex. From the original article in the Journal of the American College of Cardiology:

The threshold values of ST-segment elevation of 0.2 mV (2 mm) in some leads and 0.1 mV (1 mm) in others results from recognition that some elevation of the junction of the QRS complex and the ST segment (the J point) in most chest leads is normal. Recent studies have revealed that the threshold values are dependent on gender, age, and ECG lead ([8], [9], [10], [11] and [12]). In healthy individuals, the amplitude of the ST junction is generally highest in leads V2 and V3 and is greater in men than in women.
Recommendations

  1. For men 40 years of age and older, the threshold value for abnormal J-point elevation should be 0.2 mV (2 mm) in leads V2 and V3 and 0.1 mV (1 mm) in all other leads.
  2. For men less than 40 years of age, the threshold values for abnormal J-point elevation in leads V2 and V3 should be 0.25 mV (2.5 mm).
  3. For women, the threshold value for abnormal J-point elevation should be 0.15 mV (1.5 mm) in leads V2 and V3 and greater than 0.1 mV (1 mm) in all other leads.
  4. For men and women, the threshold for abnormal J-point elevation in V3R and V4R should be 0.05 mV (0.5 mm), except for males less than 30 years of age, for whom 0.1 mV (1 mm) is more appropriate.
  5. For men and women, the threshold value for abnormal J- point elevation in V7 through V9 should be 0.05 mV (0.5 mm).
  6. For men and women of all ages, the threshold value for abnormal J-point depression should be −0.05 mV (−0.5 mm) in leads V2 and V3 and −0.1 mV (−1 mm) in all other leads.

What does establishment of abnormal J-point mean for STEMI diagnosis? The AHA/ECC guidelines state the following:

ST-segment elevation… is characterized by ST-segment elevation in 2 or more contiguous leads and is classified as ST-segment elevation MI (STEMI). Threshold values for ST-segment elevation consistent with STEMI are:

  • J-point elevation 0.2 mV (2 mm) in leads V2 and V3 and 0.1 mV (1 mm) in all other leads (men ≥40 years old);
  • J-point elevation 0.25 mV (2.5 mm) in leads V2 and V3 and 0.1 mV (1 mm) in all other leads (men <40 years old);
  • J-point elevation 0.15 mV (1.5 mm) in leads V2 and V3 and 0.1 mV (1 mm) in all other leads (women).

So, in summary:

Older men – 2mm in V2/V3 and 1mm everywhere else
Younger men – 2.5 mm in V2/V3 and 1mm everywhere else
Women – 1.5 mm in V2/V3 and 1mm everywhere else

Shouldn’t be too difficult to remember.
Part 10: acute coronary syndromes: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.
Circulation. 2010 Nov 2;122(18 Suppl 3):S787-817
AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part VI: acute ischemia/infarction: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.
J Am Coll Cardiol. 2009 Mar 17;53(11):1003-11

Military vascular injury to the torso is deadly

Outcomes are described for military personnel with vascular injury sustained in Afghanistan and Iraq.

BACKGROUND: Military injuries to named blood vessels are complex limb- and life-threatening wounds that pose significant difficulties in prehospital and surgical management. The aim of this study was to provide a comprehensive description of the epidemiology, treatment and outcome of vascular injury among service personnel deployed on operations in Afghanistan and Iraq.
METHODS: Data from the British Joint Theatre Trauma Registry were combined with hospital records to review all cases of vascular trauma in deployed service personnel over a 5-year interval ending in January 2008.
RESULTS: Of 1203 injured service personnel, 110 sustained injuries to named vessels; 66 of them died before any surgical intervention. All 25 patients who sustained an injury to a named vessel in the abdomen or thorax died; 24 did not survive to undergo surgery and one casualty in extremis underwent a thoracotomy, but died. Six of 17 patients with cervical vascular injuries survived to surgical intervention; two died after surgery. Of 76 patients with extremity vascular injuries, 37 survived to surgery with one postoperative death. Interventions on 38 limbs included 19 damage control procedures (15 primary amputations, 4 vessel ligations) and 19 definitive limb revascularization procedures (11 interposition vein grafts, 8 direct repairs), four of which failed necessitating three amputations.
CONCLUSION: In operable patients with extremity injury, amputation or ligation is often required for damage control and preservation of life. Favourable limb salvage rates are achievable in casualties able to withstand revascularization. Despite marked progress in contemporary battlefield trauma care, torso vascular injury is usually not amenable to surgical intervention.

Outcome after vascular trauma in a deployed military trauma system
Br J Surg. 2011 Feb;98(2):228-34

Pre-hospital Airtraq use often failed

The Airtraq seems nifty when you try it on a manikin, but until now the question of whether it would be a useful pre-hospital tool was unanswered. This Austrian study provides helpful data:

OBJECTIVES: The optical Airtraq laryngoscope (Prodol Meditec, Vizcaya, Spain) has been shown to have advantages when compared with direct laryngoscopy in difficult airway patients. Furthermore, it has been suggested that it is easy to use and handle even for inexperienced advanced life support providers. As such, we sought to assess whether the Airtraq may be a reliable alternative to conventional intubation when used in the prehospital setting.
DESIGN, SETTING, AND PATIENTS: Prospective, randomized control trial in emergency patients requiring endotracheal intubation provided by anesthesiologists or emergency physicians responding with an emergency medical service helicopter or ground unit associated with the Department of Anesthesiology, General Hospital, Wiener Neustadt, Austria.
MEASUREMENTS AND MAIN RESULTS: During the 18-month study period, 212 patients were enrolled. When the Airtraq was used as first-line airway device (n=106) vs. direct laryngoscopy (n=106), success rate was 47% vs. 99%, respectively (p<.001). Reasons for failed Airtraq intubation were related to the fiber-optic characteristic of this device (i.e., impaired sight due to blood and vomitus, n=11) or to assumed handling problems (i.e., cuff damage, tube misplacement, or inappropriate visualization of the glottis, n=24). In 54 of 56 patients where Airtraq intubation failed, direct laryngoscopy was successful on the first attempt; in the remaining two and in one additional case of failed direct laryngoscopy, the airway was finally secured employing the Fastrach laryngeal mask. There was no correlation between success rates and body mass index, age, indication for airway management, emergency medical service unit, or experience of the physicians. CONCLUSIONS: Based on these results, the use of the Airtraq laryngoscope as a primary airway device cannot be recommended in the prehospital setting without significant clinical experience obtained in the operation room. We conclude that the clinical learning process of the Airtraq laryngoscope is much longer than reported in the anesthesia literature.

Use of the Airtraq laryngoscope for emergency intubation in the prehospital setting: A randomized control trial
Crit Care Med. 2011 Mar;39(3):489-93

Salt or sugar on the brain

A meta-analysis suggests hypertonic saline may be more effective at lowering intracranial pressure than mannitol. An accompanying editorial cleverly entitled ‘Salt or sugar on the brain: Does it matter except for taste?’ suggests one reason hypertonic saline (HTS) has not replaced mannitol in clinical practice is that too many different regimens of HTS, in terms of concentration, dose, bolus vs. continuous infusions, and plus or minus supplementation of colloids, have been utilised. Because only 112 patients with 184 episodes of increased ICP were treated with each medication in this meta-analysis, the editorialist agrees with the authors in suggesting a larger randomised study is needed.

OBJECTIVES: Randomized trials have suggested that hypertonic saline solutions may be superior to mannitol for the treatment of elevated intracranial pressure, but their impact on clinical practice has been limited, partly by their small size. We therefore combined their findings in a meta-analysis.
DATA SOURCES: We searched for relevant studies in MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, and ISI Web of Knowledge.
STUDY SELECTION: Randomized trials were included if they directly compared equiosmolar doses of hypertonic sodium solutions to mannitol for the treatment of elevated intracranial pressure in human subjects undergoing quantitative intracranial pressure measurement.
DATA EXTRACTION: Two investigators independently reviewed potentially eligible trials and extracted data using a preformed data collection sheet. Disagreements were resolved by consensus or by a third investigator if needed. We collected data on patient demographics, type of intracranial pathology, baseline intracranial pressure, osms per treatment dose, quantitative change in intracranial pressure, and prespecified adverse events. Our primary outcome was the proportion of successfully treated episodes of elevated intracranial pressure.
DATA SYNTHESIS: Five trials comprising 112 patients with 184 episodes of elevated intracranial pressure met our inclusion criteria. In random-effects models, the relative risk of intracranial pressure control was 1.16 (95% confidence interval, 1.00-1.33), and the difference in mean intracranial pressure reduction was 2.0 mm Hg (95% confidence interval, -1.6 to 5.7), with both favoring hypertonic saline over mannitol. A mild degree of heterogeneity was present among the included trials. There were no significant adverse events reported.
CONCLUSIONS: We found that hypertonic saline is more effective than mannitol for the treatment of elevated intracranial pressure. Our meta-analysis is limited by the small number and size of eligible trials, but our findings suggest that hypertonic saline may be superior to the current standard of care and argue for a large, multicenter, randomized trial to definitively establish the first-line medical therapy for intracranial hypertension.

Hypertonic saline versus mannitol for the treatment of elevated intracranial pressure: A meta-analysis of randomized clinical trials
Crit Care Med. 2011 Mar;39(3):554-9

Cardiac arrest drugs and pupils

Although not predictive immediately post-cardiac arrest in the emergency department, dilated unreactive pupils two or three days later on the ICU may indicate a hopeless prognosis. We know from our experience with adrenaline (epinephrine) infusions that this drug does not prevent pupils from reacting to light, but what about atropine?

A letter by Dr Sophie MacDougall-Davis in Resuscitation describes a 66 year old male patient admitted to the ICU after an intraoperative PEA arrest during which he received 3 mg intravenous atropine. Post arrest and post anaesthesia he was awake with no neurological deficit, but eight hours after the cardiac arrest his pupils remained fixed and dilated, and were dilated with only a very slight reaction the next morning and remained sluggish at forty-eight hours, normalising at seventy-two hours. A possible reason for its prolonged action may be uptake of atropine from the plasma into the aqueous humor of the eye, followed by its slow release.
Dr MacDougall-Davis cautions:

When assessing pupils in comatose cardiac arrest survivors, the potential for atropine to have a prolonged effect on pupil size and reactivity should be considered.

Atropine, fixed dilated pupils and prognostication following cardiac arrest
Resuscitation. 2011 Feb;82(2):232

Pre-hospital transcranial Doppler

The SAMU (Service d’aide médicale urgente) guys have had a run of interesting pre-hospital publications lately. In this study, one of their ultrasound-wielding physicians travelled in a car to meet comatose head injured patients in a large semi-rural territory area with up to a 120–160-min transport time to a hospital with emergency neurosurgical capability. Pre-hospital transcranial Doppler was done, the results of which appear to have influenced treatment decisions, including the pre-hospital administration of noradrenaline (norepinephrine). I think this study has answered the ‘can it be done?’ question, but further work is needed to determine whether it really makes a difference to outcome.

Background: Investigation of the feasibility and usefulness of pre-hospital transcranial Doppler (TCD) to guide early goal-directed therapy following severe traumatic brain injury (TBI).
Methods: Prospective, observational study of 18 severe TBI patients during pre-hospital medical care. TCD was performed to estimate cerebral perfusion in the field and upon arrival at the Level 1 trauma centre. Specific therapy (mannitol, noradrenaline) aimed at improving cerebral perfusion was initiated if the initial TCD was abnormal (defined by a pulsatility index >1.4 and low diastolic velocity).
Results: Nine patients had a normal initial TCD and nine an abnormal one, without a significant difference between groups in terms of the Glasgow Coma Scale or the mean arterial pressure. Among patients with an abnormal TCD, four presented with an initial areactive bilateral mydriasis. Therapy normalized TCD in five patients, with reversal of the initial mydriasis in two cases. Among these five patients for whom TCD was corrected, only two died within the first 48 h. All four patients for whom the TCD could not be corrected during transport died within 48 h. Only patients with an initial abnormal TCD required emergent neurosurgery (3/9). Mortality at 48 h was significantly higher for patients with an initial abnormal TCD.
Conclusions: Our preliminary study suggests that TCD could be used in pre-hospital care to detect patients whose cerebral perfusion may be impaired.

Pre-hospital transcranial Doppler in severe traumatic brain injury: a pilot study
Acta Anaesthesiol Scand. 2011 Apr;55(4):422-8