Advances in Pre
Advances in Prehospital Care
CDR GIRARD POIRIER, MC USN
Introduction
Trauma is the leading cause of death for patients up to their 4 th decade of life.
Essential to optimize care for trauma patients both outside and inside the hospital setting.
Emergency Medical Services rely on advances in therapy and management. Such advances usually start in the hospital and are then carried on to the EMS system.
History
The concept of the modern pre-hospital care system for trauma patients goes back to the introduction of the “flying ambulances” by Napoleon's private surgeon, Dominique-Jean Larrey, in 1792.
The “flying ambulances” were horse drawn carriages, bringing physicians or medical supplies to the battlefield and transporting wounded soldiers away from the front line.
All modern EMS systems still follow this early idea of either bringing the physician to the patient or bringing the patient to the physician.
History
The care of trauma patients is significantly influenced by military conflicts.
Korean and Vietnam wars saw the first airborne rescue missions by helicopters on a large scale. The civilian EMS systems quickly implemented this new concept into the rescue of civilian trauma patients.
Low volume resuscitation, the revival of tourniquets, and hemostatic agents will clearly influence the care of civilian trauma patients in the future.
Design
Most EMS systems utilize some sort of a multi-tier approach
Some countries like Germany and France are using EMS systems which are based on the idea of bringing the physician to the patient.
EMS systems in the US are based on the premise of bringing paramedic providers, who are trained to perform a limited number of medical procedures in the field to the patients.
The emphasis is focused on rapid transport to the hospital, after the basic rescue techniques, such as airway management and fluid resuscitation, were performed at the scene.
Airway Management
Loss of airway or breathing is the most rapid cause of death.
The airways of severely injured patients need to be secured as soon as possible.
Airway management in the field is often more difficult than intubations in the operating room or the emergency department
Different provider training and experience, patient location, and coexisting medical or surgical problems are all factors.
Devices used in anesthesiology have been introduced to prehospital care providers. These devices range from laryngoscopes and different laryngoscope blades to oral and nasal airways. More recently introduced devices include the elastic bougie, and even more recently, supraglottic devices.
Airway Management
Endotracheal Intubation
:
As stated, can be difficult in the field setting
Standard equipment may not be adequate to secure an airway
Devices have been developed to aid in difficult and failed intubation attempts.
Airway Management
Glidescope
Provides direct visualization of airway structures.
Rigid, preformed Stylet used with
ETT
Airway Management
Multiple other visually assisted devices are available .
Ambu ® Pentax Airway Scope
C-MAC ® Video Laryngoscope
McGrath ® Video Laryngoscope
Airway Management
Elastic Bougie. Used by anesth. Since 1949.
Now readily available to
EMS providers to aid in intubations.
“ride” the glottis into the trachea
Can easily feel tracheal rings with tip of bougie.
ETT placed over bougie
Airway Management
Supraglottic Device. Laryngeal Mask
Airway (LMA). No visualization required.
Easily inserted
Tip over esoph with balloon inflating over glottis
Not a definitive airway
Airway Management
CombiTube:
Dual balloon device
Easy inertion
Not definitive
Airway Management
King LT
Dual balloon, supraglottic device
Single inflation port as compared to the
Combitube.
Not definitive
Gastric access available
Airway Management
Studies in the US showing increased risk of morbidity and mortality with pre-hospital RSI / intubation
Increased in pediatric and TBI populations
Paradigm may shift to non-definitive airways in these poplations
Further study required
Circulatory Access
Paramedics and other prehospital providers have been placing intravenous access as a standard treatment since the beginning of prehospital care.
Certain patients such as hypovolemic patients, intravenous drug abusers, burn patients, and children, peripheral intravenous access may not be possible
Circulatory Access
Intraosseous
Access:
FAST IO
Circulatory Access
Intra-Osseous
Easy IO
Proximal and distal Tibia, Prox Humerus
Circulatory Access
Pitfalls to intraosseous access:
is the increased infection risk blood products cannot be given through this access. the patient still requires intravenous access one at the hospital and the intraosseous needle (or needles) needs to be removed.
For this reason, intraosseous access is often used as a last resort when peripheral IV access can not be established in the field.
Hemorrhage Control
Tourniquets
:
Are experiencing a revival after they were all but eliminated in the early
80s when the fear of extended soft tissue damage, nerve damage and the potential loss of the extremity was feared if the tourniquet was used for too long.
The different types of tourniquets (rubber, cloth, and windlass) are successful in eliminating distal pulses when applied above and below the knee or elbow. The location of the tourniquet may allow a lower amputation with preservation of the joint
Hemorrhage Control
Hemostatic Dressings:
HemCon ® bandage: becoming extremely adherent when in contact with blood. This adhesivelike action seals the wound and controls bleeding.
Multiple patch sizes.
Hemorrhage Control
QuickClot ® ACS / CombatGauze
(Hemostatic Dressing)
Fluid molecules are adsorbed by the QuikClot
ACS™material. This causes rapid localized coagulation and the formation of a stable blood clot
Exothermic reaction may occur if excessive water is present on wound site.
Utilized by US Military
Hemorrhage Control
Granular Agent
:
WoundStat
:
Absorbs water and forms a claylike seal within the wound
Found to be superior at hemostatis
However, further studies have shown signif inflammatory rxn, neurovasc changes.
Granules have the potential of traveling intravasc.
Removed from use by US military
Monitoring
End Tidal CO2 Monitoring:
Introduced in many EMS systems and the emergency room as a way to verify tracheal position of an ETT.
Also useful in guiding mechanical ventilation, especially when transport ventilators are used in which the minute volume can be better controlled than in manual bag ventilation.
Assessment of effectiveness of cardio pulmonary resuscitation (CPR), as larger volumes of end-tidal CO
2 indicate not only effective ventilation but also better cardiac output
Monitoring
End Tidal CO2 (continued):
End-tidal capnography in the prehospital setting can reduce the incidence of severe inadvertent hyperventilation by over 50%
Davis DP, Dunford JV, Ochs M, Park K, Hoyt DB. The use of quantitative end-tidal capnometry to avoid inadvertent severe hyperventilation in patients with head injury after paramedic rapid sequence intubation. J Trauma. 2004;56:808–14
In intubated patients with traumatic brain injury, the survival rate was increased twofold when the arrival pCO
2 was between 30 and 49 mm Hg
Davis DP, Idris AH, Sise MJ, Kennedy F, Eastman AB, Velky T, et al. Early ventilation and outcome in patients with moderate to severe traumatic brain injury. Crit Care Med. 2006;34:1202–8
Artificial Blood Products
“Every minute of every day, someone needs blood.”
The Military use was the primary driver to develop blood substitutes.
Public concern over blood safety, particularly from an infectious diseases standpoint.
Increased utilization of blood products by a growing and ageing population, compounded by increasing complexity of medical and surgical treatments
Artificial Blood Products
Advantages of Blood Substitutes
Universally compatible
Pure and non
‐ toxic
Stability and shelf life
Rapid and widespread availability
Artificial Blood Products
Two major oxygen ‐ based substitutes
1) BiomimeticApproach: Hemoglobin Based Oxygen Carriers (HBOCs)
2) Abiotic Approach: Perfluorocarbon Emulsion (PFCEs)
Artificial Blood Products
HBOC’s
Hemopure – crosslinked bovine polyHb
Hemolink – crosslinked human oligoHb
PolyHeme – crosslinked human polyHb
Hemospan –PEG modified human Hb
HemoZyme – polynitoxylated human Hb
Optro – recombinant human Hb
Artificial Blood Products
Hemopure in the Trauma Setting
Currently in use in South Africa, approved 2001
In U.S., found not to be inferior to blood
FDA suspended human trials due to safety concerns mainly from vasoconstrictive responses to infusion.
Studies have been proposed to co-infuse a nitric oxide donor such as nitroglycerin in a fixed ratio, in a single-bag compound, or as a separate infusion. There is little likelihood that trauma surgeons will accept a product developed to treat shock that requires co-infusion of a vasodilator.
Artificial Blood Products
Other HBOC’s
Sixteen trials involving 5 different products and 3711 patients in varied patient populations were identified. Overall, there was a statistically significant increase in the risk of death (164 deaths in the
HBBS-treated groups and 123 deaths in the control groups; relative risk [RR], 1.30; 95% confidence interval [CI], 1.05-1.61) and risk of MI
(59 MIs in the HBBS-treated groups and 16 MIs in the control groups;
RR, 2.71; 95% CI, 1.67-4.40) with these HBBSs. Subgroup analysis of these trials indicated the increased risk was not restricted to a particular HBBS or clinical indication.
CONCLUSION: Based on the available data, use of HBBSs is associated with a significantly increased risk of death and MI.
Nathanson C. Cell-free hemoglobin-based blood substitutes and risk of myocardial infarction and death: a meta-
analysis. JAMA 2008 May 21;299(19):2304-12
Artificial Blood Products
Perflurocarbon Emulsions :
Current PFCE products are referred to as second generation PFCE's and are marketed as oxygen therapeutics for patients at risk of acute hypoxia resulting from transient anemia, blood loss or ischemia.
Data from numerous studies, including a European Phase III study of 492 patients investigating the use of Oxygent™ in general surgery, showed that the product reduced the need for transfused blood. While a Phase
III trial involving CABG in the US was halted due to high stroke rates in both the experimental and control groups, Alliance is hoping to initiate further Phase III studies involving general surgery.
Currently, there are four US clinical sites involved and SYBD hopes to eventually have six. Future Phase II trials will involve the use of Oxycyte™ in CABG, and heart valve replacement surgery, among others.
A Few Controversial Topics
EMS / Field Intubation:
The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury.
J Trauma. 2003 Mar;54(3):444 ‐ 53. Davis DP, Hoyt DB, Ochs M, Fortlage D, Holbrook T,
Marshall LK, Rosen P.Department of Emergency Medicine, UC San Diego, CA
92103
‐
8676, USA.
Controversies
OBJECTIVE: To evaluate the effect of paramedic rapid sequence intubation (RSI) on outcome in patients with severe traumatic brain injury.
• METHODS: Adult major trauma victims were prospectively enrolled over two years
RESULTS: A total of 209 trial patients were hand matched to 627 controls. The groups were similar with regard to all matching parameters, admission vital signs, frequency of specific head injury diagnoses, and incidence of invasive procedures.
Controversies
Results :
Mortality was significantly increased in the trial cohort versus controls for all patients (33.0% versus 24.2%, p <
0.05)
Factors that may have contributed to the increase in mortality include transient hypoxia, inadvertent hyperventilation, and longer scene times associated with the RSI procedure
Controversies
Cochrane Review (9 studies to date)
Quite a few studies have been conducted to address the question of prehospital endotracheal intubation in major trauma victims needing airway management. All of them are of retrospective design most of them show that there is increased mortality
longer transit times with prehospital endotracheal intubation.
The reasons could be difficulty in ascertaining tube position,
paramedic experience,
hyperventilation,
transient hypoxia, or
lack of sufficient pre
‐ oxygenation prior to RSI.
Clinical Bottom Line ‐ Prehospital endotracheal intubation is associated with increased mortality in patients with moderate to severe traumatic brain injury
Controversies
Spine Immobilization
Previous studies have suggested that prehospital spine immobilization provides minimal benefit in pts with penetrating trauma
Haut ER, et al. Spine Immobilization in Penetrating
Trauma: More Harm Than Good? J Trauma. 2010
Jan;68(1):115
‐
121
Controversies
45,284 pts with penetrating trauma retrospectively analyzed 8.1% overall mortality
4.3% underwent spine immobilization. Unadjusted mortality was double in spine ‐ immobilized pts (14.7% vs 7.2%, p<0.001)
OR of death those was 2.06 (95% CI: 1.35
‐
3.13)
Only 30 pts (0.01%) had incomplete spinal cord injury and needed operative treatment
NNT to potentially benefit one pt = 1032
NNH to potentially contribute to one death = 66
Controversies
Harmful or Helpful ?
Comes down to EMS medical treatment protocols
Good decision making by ALS providers
Nexus Criteria for Spine Immobilization
Midline cervical pain
Neurologic deficit
Mental status change
Distracting injury
ETOH or Drug use association
Controversies
Does Helicopter Transport of trauma patients improve outcomes?
A topic of much discussion
Multitude of studies with results for and against.
Which has the best studies
Number of medical helicopters has doubled in the last 4 years in the US.
Controversies
Air versus ground transport of the major trauma patients: a natural experiment
McVey J, Petrie DA, Tallon JM. Department of Emergency Medicine, Dalhousie
University, Nova Scotia, Canada. mcveyj@dal.ca
Prehospital Emerg Care. 2010
Jan-Mar;14(1):45-50 compared the outcomes of adult trauma patients transported to a level I trauma center by helicopter vs. ground ambulance.
Retrospective database review
Air transport of the adult major trauma patient is associated with significantly improved survival as compared with ground transport.
Controversies
Air versus ground transport of major trauma patients to a tertiary trauma centre: a province
‐ wide comparison using TRISS analysis
Alex D. Mitchell,
*
John M. Tallon,
† and Beth Sealy
†
From the *Division of General
Surgery and the †Nova Scotia Trauma Program, Queen Elizabeth II Health
Sciences Centre, Dalhousie University, Halifax, NS. Can J Surg. 2007 April; 50(2):
129–133
The transport of trauma patients with an ISS ≥ 12 by a provincially dedicated rotor wing air medical service was associated with statistically significantly better outcomes than those transported by standard ground ambulance. This is the first large Canadian study to specifically compare the outcome of patients transported by ground with those transported by air.
Retrospective analysis of 823 trauma patients
Controversies
Shatney CH, Homan SJ, Sherek JP, et al. The utility of helicopter transport of trauma patients from the injury scene in an urban trauma system. J Trauma.
2002;53(5):817-22
10-year retrospective review of 947 consecutive trauma patients transported to the Santa Clara
Valley trauma center.
Blunt trauma: 911
Penetrating trauma: 36
Controversies
Only 17 patients (1.8%) underwent surgery for immediately lifethreatening injuries.
Helicopter arrival faster = 54.7%
Helicopter arrival slower = 45.3%
Only 22.4% of the study population were possibly helped by helicopter transport.
CONCLUSION: The helicopter is used excessively for scene transport of trauma victims in our metropolitan trauma system. New criteria should be developed for helicopter deployment in the urban trauma environment
Controversies
Eckstein M, Jantos T, Kelly N, et al. Helicopter transport of pediatric trauma patients in an urban emergency medical services system: a critical analysis. J Trauma, 2002;53:340-344.
Retrospective review of 189 pediatric trauma patients (<15) transported by helicopter from the scene in LA.
Median age: 5 years
RTS > 7 = 82%
ISS < 15 = 83%
Admitted to ICU = 18%
Discharged from ED = 33%
RTS - Revised Trauma Score
GCS Points SBP Points RR Points
15-13 4 >89 4 10-29 4
12-9 3 76-89 3 >29 3
8-6 2 50-75 2 6-9 2
5-4 1 1-49 1 1-5 1
3 0 0 0 0 0
The score range is 0-12. In START triage , a patient with an RTS score of 12 is labeled delayed, 11 is urgent , and 10-3 is immediate. Those who have an
RTS below 3 are declared dead and should not receive certain care because they are highly unlikely to survive without a significant amount of resources.
ISS – Injury Severity Score
The Injury Severity Score (ISS) is an anatomical scoring system that provides an overall score for patients with multiple injuries. Each injury is assigned an Abbreviated Injury Scale (AIS) score and is allocated to one of six body regions (Head, Face, Chest, Abdomen, Extremities
(including Pelvis), External). Only the highest AIS score in each body region is used. The 3 most severely injured body regions have their score squared and added together to produce the ISS score
The ISS scores ranges from 1 to 75 (i.e. AIS scores of 5 for each category). If any of the three scores is a 6, the score is automatically set at 75. Since a score of 6 ("unsurvivable") indicates the futility of further medical care in preserving life, this may mean a cessation of further care in triage for a patient with a score of 6 in any category .
Controversies
CONCLUSION:
The majority of pediatric trauma patients transported by helicopter in our study sustained minor injuries. A revised policy to better identify pediatric patients who might benefit from helicopter transport appears to be warranted
Controversies
Helicopter emergency medical services for adults with major trauma
Galvagno SM. Cochrane Database Syst Review. 2013 Mar 28;3
25 studies reviewed
No randomized trials, significantly flawed methodology in most. Groups not well matched and heterogeneous.
5 studies focused on TBI, no change in mortality with HEMS
Other studies were mixed
Difficult to draw conclusions.
Controversies
Majority of data does show that helicopters are over utilized for trauma scene responses especially in pediatric patients.
Over triage of trauma patients primary factor
Costs and risks may not justify benefit for the vast majority of trauma patients.
Triage criteria should be based on physiological parameters and not mechanism of injury.
Controversies
Medical helicopters accept the most dangerous missions in commercial aviation. They fly unplanned routes a few hundred feet above the ground, often below radar. They land on highways, mountains and farms, miles from the nearest airport weather station
The majority have no autopilot system or co-pilot to assist the pilot in emergencies. Medical helicopters are not required to have terrain awareness and warning systems (TAWS), night-vision goggles, flight data recorders, detailed weather reporting or ground personnel in charge of flight dispatch and in-flight tracking.
medical helicopters crash at twice the rate of other air taxis and are exponentially more dangerous than commercial airliners, according to a 2009 study by Ira Blumen, medical and program director of the University of Chicago
Aeromedical Network. Air ambulances have crashed 272 times between 1972 and 2010, killing 276 people.
Controversies
Statistically speaking, EMS Aircrews have the most dangerous job in America with the highest death rates.
2006 NTSB report analyzing all air-ambulance crashes between January 2002 and January 2005 (air ambulances include small fixed-wing planes) found that improved flight risk assessment and dispatch and tracking systems could have prevented nearly half.
In Arizona, 43 percent of patients transported by helicopter to hospital ERs were discharged within 24 hours, suggesting most didn't need a helicopter at all. In
Maryland, the 24-hour discharge rate for patients transported by state police helicopters was 41 percent
Controversies
Studies disagree on whether medical helicopters improve EMS response times and patient survival rates.
Besides severity of injury, the key factor may be flight time. Helicopters are significantly faster than ground ambulances when retrieving patients more than 45 miles away from a hospital, according to a study published in the Journal of Trauma in 2005. But closer than 45 miles, ground vehicles are just as fast--or faster--than helicopters.
Training for paramedics is imperative on whether or not to request helicopter transports .
