Category Archives: PHARM

Prehospital and Retrieval Medicine

Weight formula validation

Further validation of the UK-derived Luscombe weight formula has been made in the Australian setting. The nice simple formula for estimating the weight of a child based on age is:

Weight (kg) = 3 x age(years) + 7

It was compared with other formulae including the Best Guess formula, which is a bit more difficult to apply as the formula varies according to age range. This is reported in a previous post.
The authors provide the following cautionary advice:
“Whereas age-based formulae are, in the main, easy to calculate, the evidence suggests that ethnicity and body habitus pose serious challenges to their accuracy. In comparative studies, age-based formulae were found to be less accurate than the Broselow tape and parental estimate, with parental estimate being the most accurate weight estimation method. In light of this evidence, age-based formulae should only be used when these more accurate methods are not available.”

OBJECTIVE: Several paediatric weight estimation methods have been described for use when direct weight measurement is not possible. A new age-based weight estimation method has recently been proposed. The Luscombe formula, applicable to children aged 1-10 years, is calculated as (3 × age in years) + 7. Our objective was to externally validate this formula using an existing database.
METHOD: Secondary analysis of a prospective observational cohort study. Data collected included height, age, ethnicity and measured weight. The outcome of interest was agreement between estimated weight using the Luscombe formula and measured weight. Secondary outcome was comparison with performance of Argall, APLS and Best Guess formulae. Accuracy of weight estimation methods was compared using mean difference (bias), 95% limits of agreement, root mean square error and proportion with agreement within 10%.
RESULTS: Four hundred and ten children were studied. Median age was 4 years; 54.4% were boys. Mean body mass index was 17 kg/m(2) and mean measured weight was 21.2 kg. The Luscombe formula had a mean difference of 0.66 kg (95% limits of agreement -9.9 to +11.3 kg; root mean square error of 5.44 kg). 45.4% of estimates were within 10% of measured weight. The Best Guess and Luscombe formulae performed better than Argall or APLS formulae.
CONCLUSION: The Luscombe formula is among the more accurate age-based weight estimation formulae. When more accurate methods (e.g. parental estimation or the Broselow tape) are not available, it is an acceptable option for estimating children’s weight.

Validation of the Luscombe weight formula for estimating children’s weight
Emerg Med Australas 2011 Feb;23(1):59-62

Performance measures for HEMS services

A recent study highlights the need for uniform standards of outcome data collection in Helicopter Emergency Medical Services (HEMS) in Great Britain and aero-medical retrieval services in Australia. Suggested patient outcome measurements by Britsh and Australian air medical respondents to the survey included:

  1. Mortality versus TRISS predicted mortality
  2. APACHE/ TRISS predicted mortality versus actual mortality.
  3. Use of national audit tools (eg, TARN)
  4. Nationally agreed Key Performance Indicators (KPIs)
  5. Clinical outcomes benchmarked against other services
  6. In-mission clinical indicators (eg, unanticipated procedures, adverse events)
  7. Physiological scoring linked to outcome measures
  8. ISS versus survival/disability
  9. KPIs from a national body. Mortality in isolation is not a useful marker of quality
  10. Clinical KPIs provided there is a reliable method of data collection
  11. Long-term outcome
  12. Interventions performed by doctors that contribute to patient mortality/morbidity.

Background Performance outcome measures are an essential component of health service improvement. Whereas hospital critical care services have established performance measures, prehospital care services have less well-established outcome measures and this has been identified as a key issue for development. Individual studies examining long-term survival and functional outcome measures have previously been used to evaluate prehospital care delivery. There is no set of standardised patient outcome measures for Helicopter Emergency Medical Services (HEMS) in the UK or Air Medical Services (AMS) in Australia. The aim of this study is to document the patient outcome measures currently in use within British HEMS and Australian AMS.
Methods This is an observational study analysing point prevalence of practice as of November 2009. A structured questionnaire was designed to assess the method of routine patient follow-up, and the timing and nature of applied patient outcome measures.
Results Full responses were received from 17/21 (81%) British services and 6/7 (86%) Australian services. The overall response rate was 82%.
Conclusions HEMS in Britain and Australian aeromedical retrieval services do not have uniform patient outcome measures. Services tend not to follow-up patients beyond 24 h post transfer. Patient outcome data are rarely presented to an external organisation and there is no formal data comparison between surveyed services. Services are not satisfied that the data currently being collected reflects the quality of their service.

Performance measurement in British Helicopter Emergency Medical Services and Australian Air Medical Services
Emerg Med J. 2011 Feb 3. [Epub ahead of print]

EMS makes a difference

A Position Statement of the National Emergency Medical Services Advisory Council summarises the substantial evidence base documenting improved patient outcomes resulting from prehospital interventions and emergency medical services (EMS) systems. The fully referenced document is available in free full text .

The document concludes with this summary:

  • EMS makes a difference by producing clinically meaningful reductions in time to definitive treatment and improved health outcomes for patients with STEMI. Trained EMS providers are proficient in the capture and interpretation of 12-lead ECGs, can andshould make or participate in triage decisions to bypass closer hospitals in favor of to PCI-capable facilities, when clinically indicated. Efforts should continue to educate the public to call 9-1-1 at the first sign of a heart attack.
  • EMS makes a difference by decreasing the times to CPR and defibrillation, defined as the two critical factors for surviving cardiac arrest.
  • EMS makes a difference and is a critical component of effective stroke care. EMS must advocate for quality, standardized stroke protocols, performance improvement systems and training, and expedient transport of stroke patients to specialty care centers. EMS systems must partner with their dispatch agencies to ensure the use of quality Emergency Medical Dispatch protocols that provide proper stroke care instructions and activate appropriate resources. Efforts should continue to educate the public to call 9-1-1 at the first sign of a stroke.
  • EMS makes a difference by improving survival and neurological function for patients with respiratory emergencies. Proper prehospital care decreases the need for intubations and the number of required hospital admissions and improves cerebral performance in patients with respiratory distress. The addition of CPAP to the EMS tool kit provides immediate and longer-term benefits and further reduces hospitalization rates and healthcare costs.
  • EMS makes a difference by allowing EMS providers to use diagnostic tools such as blood glucometry, pulse oximetry, and 12-lead ECGs to efficiently evaluate patients and determine whether more advanced evaluation is necessary.
  • EMS makes a difference by treating many diabetic patients at home without the need for transport; thereby improving patient satisfaction and decreasing healthcare costs.
  • EMS makes a difference by accurately identifying patients experiencing out-of-hospital cardiac arrest who have no realistic chance of survival and determining whether transport to a hospital is warranted, thus reducing transports, decreasing hospital and patient costs, and increasing the availability of EMS resources.
  • EMS makes a difference with its expanding role in the healthcare system. EMS has the potential to provide improved patient outcomes and more customer satisfying primary care while offering clinically appropriate alternatives to hospital transport in addition to standard 9-1-1 responses. In a fully integrated healthcare system, EMS will provide preventive services, acute care, and overall community health.
  • EMS makes a difference in trauma care by providing rapid assessment, early notification to trauma centers, and rapid triage and transport to trauma centers, when appropriate. EMS will continue to be the community’s safety net.
  • EMS makes a difference with pediatric shock patients when shock is recognized and treated aggressively. The healthcare system must advocate for a systems approach to pediatrics similar to trauma, STEMI, and stroke systems of care and standardized training for all healthcare providers.

 

EMS Makes a Difference: Improved clinical outcomes and downstream healthcare savings
free full text

In V.Fib and talking to you!

Some patients with severe refractory heart failure are kept alive thanks to implantable pumps such as the left ventricular assist device (LVAD). Many emergency physicians are likely to be unfamiliar with these but could encounter patients who have them. One particular peculiarity is that latter generation devices maintain non-pulsatile flow and provide or assist cardiac output independent of cardiac rhythm. In extreme situations patients can have life-sustaining cardiac outputs without palpable pulses or even audible heart sounds.

Click on image for Wikipedia article

A great example of how weird this can get is provided by a case of a 66 year male with an LVAD (HeartMate II (Thoratec Corporation)) who presented due to spontaneous discharge of his internal cardioverter-defibrillator (ICD). He was alert but had no pulses, and no detectable blood pressure using both a manual sphygmomanometer and an automated non-invasive blood pressure device. His 12 lead showed ventricular fibrillation. An invasive blood pressure showed a mean arterial pressure (mAP) of 80 mmHg. Several hours later his VF was successfully terminated and his mAP remained 80 mmHg
Some interesting points made by the authors include:

  • CPR was unnecessary in this guy but in cases of severe RV dysfunction it might need to be done to provide flow into the LV.
  • A danger of CPR in patients with an LVAD is the risk of damage to the device or ventricular rupture

LVAD use is significantly increasing so we can expect to encounter more episodes of previously impossible presentations to our emergency departments.

ABSTRACT
Optimal medical treatment, cardiac resynchronization, and the use of an implantable cardioverter defibrillator are established therapies of severe congestive heart failure. In refractory cases, left ventricular assist devices are more and more used not only as bridging to cardiac transplantation but also as destination therapy. Ventricular arrhythmias may represent a life-threatening condition and often result in clinical deterioration in patients with congestive heart failure. We report a case of asymptomatic sustained ventricular fibrillation with preserved hemodynamics caused by a nonpulsatile left ventricular assist device. Consecutive adequate but unsuccessful discharges of the implantable cardioverter defibrillator were the only sign of the usually fatal arrhythmia, prompting the patient to consult emergency services. Electrolyte supplementation and initiation of therapy with amiodarone followed by external defibrillation resulted in successful restoration of a stable cardiac rhythm after 3.5 hours.

Asymptomatic Sustained Ventricular Fibrillation in a Patient With Left Ventricular Assist Device
Ann Emerg Med. 2011 Jan;57(1):25-8.

Pre-hospital RSI and single use blades

Single-use metal laryngoscope blades were compared in a randomised trial in the pre-hospital setting by French SAMU physicians. First-pass intubation success (defined as one advancement of the tube in the direction of the glottis during direct laryngoscopy) was similar between conventional and disposable metal blades.

A French doctor (not involved in the study)

STUDY OBJECTIVE: Emergency tracheal intubation is reported to be more difficult with single-use plastic than with reusable metal laryngoscope blades in both inhospital and out-of-hospital settings. Single-use metal blades have been developed but have not been compared with conventional metal blades. This controlled trial compares the efficacy and safety of single-use metal blades with reusable metal blades in out-of-hospital emergency tracheal intubation.
METHODS: This randomized controlled trial was carried out in France with out-of-hospital emergency medical units (Services de Médecine d’Urgence et de Réanimation). This was a multicenter prospective noninferiority randomized controlled trial in adult out-of-hospital patients requiring emergency tracheal intubation. Patients were randomly assigned to either single-use or reusable metal laryngoscope blades and intubated by a senior physician or a nurse anesthetist. The primary outcome was first-pass intubation success. Secondary outcomes were incidence of difficult intubation, need for alternate airway devices, and early intubation-related complications (esophageal intubation, mainstem intubation, vomiting, pulmonary aspiration, dental trauma, bronchospasm or laryngospasm, ventricular tachycardia, arterial desaturation, hypotension, or cardiac arrest).
RESULTS: The study included 817 patients, including 409 intubated with single-use blades and 408 with a reusable blade. First-pass intubation success was similar in both groups: 292 (71.4%) for single-use blades, 290 (71.1%) for reusable blades. The 95% confidence interval (CI) for the difference in treatments (0.3%; 95% CI -5.9% to 6.5%) did not include the prespecified inferiority margin of -7%. There was no difference in rate of difficult intubation (difference 3%; 95% CI -7% to 2%), need for alternate airway (difference 4%; 95% CI -8% to 1%), or early complication rate (difference 3%; 95% CI -3% to 8%).
CONCLUSION: First-pass out-of-hospital tracheal intubation success with single-use metal laryngoscopy blades was noninferior to first-pass success with reusable metal laryngoscope blades.

Out-of-Hospital Tracheal Intubation With Single-Use Versus Reusable Metal Laryngoscope Blades: A Multicenter Randomized Controlled Trial
Ann Emerg Med. 2011 Mar;57(3):225-31

Delayed door-to-balloon even with helicopters

For a whole bunch of reasons, patients with ST-elevation myocardial infarction who undergo interhospital transfer for primary percutaneous coronary intervention may not meet the required 90 minute door-to-balloon time. In a new study of patients transferred by helicopter, only 3% of STEMI patients transferred for reperfusion met the 90-minute goal. Should this result in an increase in the use of fibrinolysis at non–percutaneous coronary intervention hospitals?

Opportunity for gratuitous helicopter shot never knowingly declined

STUDY OBJECTIVE: Early reperfusion portends better outcomes for ST-segment elevation myocardial infarction (STEMI) patients. This investigation estimates the proportions of STEMI patients transported by a hospital-based helicopter emergency medical services (EMS) system who meet the goals of 90-minute door-to-balloon time for percutaneous coronary intervention or 30-minute door-to-needle time for fibrinolysis.
METHODS: This was a multicenter, retrospective chart review of STEMI patients flown by a hospital-based helicopter service in 2007. Included patients were transferred from an emergency department (ED) to a cardiac catheterization laboratory for primary or rescue percutaneous coronary intervention. Out-of-hospital, ED, and inpatient records were reviewed to determine door-to-balloon time and door-to-needle time. Data were abstracted with a priori definitions and criteria.
RESULTS: There were 179 subjects from 16 referring and 6 receiving hospitals. Mean age was 58 years, 68% were men, and 86% were white. One hundred forty subjects were transferred for primary percutaneous coronary intervention, of whom 29 had no intervention during catheterization. For subjects with intervention, door-to-balloon time exceeded 90 minutes in 107 of 111 cases (97%). Median door-to-balloon time was 131 minutes (interquartile range 114 to 158 minutes). Thirty-nine subjects (21%) received fibrinolytics before transfer, and 19 of 39 (49%) received fibrinolytics within 30 minutes. Median door-to-needle time was 31 minutes (interquartile range 23 to 45 minutes).
CONCLUSION: In this study, STEMI patients presenting to non-percutaneous coronary intervention facilities who are transferred to a percutaneous coronary intervention-capable hospital by helicopter EMS do not commonly receive fibrinolysis and rarely achieve percutaneous coronary intervention within 90 minutes. In similar settings, primary fibrinolysis should be considered while strategies to reduce the time required for subsequent interventional care are explored.

Reperfusion Is Delayed Beyond Guideline Recommendations in Patients Requiring Interhospital Helicopter Transfer for Treatment of ST-segment Elevation Myocardial Infarction.
Ann Emerg Med. 2011 Mar;57(3):213-220

EZ-IO in pre-hospital care

French pre-hospital physicians liked the EZ-IO intraosseous drill, using it for drugs (including rapid sequence intubation drugs) and fluids in the pre-hospital setting. There was a very high insertion success rate.
OBJECTIVE: Intraosseous access is a rapid and safe alternative when peripheral vascular access is difficult. Our aim was to assess the safety and efficacy of a semi-automatic intraosseous infusion device (EZ-IO) when using a management algorithm for difficult vascular access in an out-of-hospital setting.
METHODS: This was a one-year prospective, observational study by mobile intensive care units. After staff training in the use of the EZ-IO device and provision of a management algorithm for difficult vascular access, all vehicles were equipped with the device. We determined device success rate and ease of use, resuscitation fluid volume and drugs administered by the intraosseous route, and complications at insertion site.

RESULTS: A total of 4666 patients required vascular access. The EZ-IO device was used in 30 cardiac arrest patients (25 adults; 5 children) and 9 adults with spontaneous cardiac activity. The success rate for first insertion was 84%. Overall success rate (max. 2 attempts) was 97%. The device was used for fluid resuscitation in 16 patients (mean volume: 680ml), adrenaline administration in 24 patients, and rapid sequence induction in 2 patients. There was only one local complication (transient local inflammation).
CONCLUSIONS: On implementation of an algorithm for the management of difficult vascular access, the EZ-IO device proved safe and highly effective in both adult and paediatric patients in an out-of-hospital emergency setting. It is a suitable device for consideration as a first-line option for difficult vascular access in this setting.
Efficacy and safety of the EZ-IOTM intraosseous device: Out-of-hospital implementation of a management algorithm for difficult vascular access
Resuscitation. 2011 Jan;82(1):126-9

Limits on resuscitative thoractomy in ED

Eighteen trauma centers contributed ED resuscitative thoracotomy data to a study that commenced enrollment in January 2003. During the ensuing 6 years, 56 patients survived to hospital discharge. Mean age was 31.3; the youngest was a 15-year-old female and the oldest was a 64-year-old male; 93% were male. Injury mechanism was stab wound (SW) in 30 patients, gunshot wound (GSW) in 21 patients, and blunt trauma in 5 patients.
The most common injury was a SW to a ventricle (n =17), accounting for 30% of survivors, followed by a GSW to the lung (n =9) in 16%. There were five survivors (9%) after blunt trauma. Two patients were revived with isolated head trauma who had deteriorated from extensive hemorrhage, one from an open blunt skull fracture (who had 5 minutes of prehospital CPR and left the hospital neurologically intact.) and the other from SWs to the scalp. Two patients also survived with isolated neck injuries: a SW to the vertebral artery and a GSW to the internal carotid artery.
34% of survivors underwent prehospital CPR. Corroborating the reported duration of CPR, the mean base deficit (BD) was 23.3 mequiv/L (range, 14–32 mequiv/L) in those undergoing CPR >5 minutes. In the SW group, the duration was 2 minutes to 10 minutes; the sole survivor after 10 minutes had ventricular wounds with pericardial tamponade. In the GSW group, prehospital CPR was from 1 minute to 15 minutes. The only patient surviving with 15 minutes of CPR also had a ventricular wound with pericardial tamponade but had a moderate neurologic deficit at discharge. In the blunt group, CPR ranged from 3 minutes to 9 minutes; the survivor with 9 minutes of CPR had an atrial rupture with pericardial tamponade.
Seven patients survived with asystole at ED arrival; of significance, all patients had pericardial tamponade. At the time of hospital discharge, three of these patients (43%) had functional neurologic recovery.
The authors state: ‘most recent edition of the ACSCOT advanced trauma life support manual continues to declare “patients sustaining blunt injuries who arrive pulseless but with myocardial electrical activity are not candidates for resuscitative thoracotomy”. But these statements are not congruent with most of the recent literature.

Recommended Limits of Resuscitative Thoracotomy in the ED

 

BACKGROUND: Since the promulgation of emergency department (ED) thoracotomy >40 years ago, there has been an ongoing search to define when this heroic resuscitative effort is futile. In this era of health care reform, generation of accurate data is imperative for developing patient care guidelines. The purpose of this prospective multicenter study was to identify injury patterns and physiologic profiles at ED arrival that are compatible with survival.
METHODS: Eighteen institutions representing the Western Trauma Association commenced enrollment in January 2003; data were collected prospectively.
RESULTS: During the ensuing 6 years, 56 patients survived to hospital discharge. Mean age was 31.3 years (15-64 years), and 93% were male. As expected, survival was predominant in those with thoracic injuries (77%), followed by abdomen (9%), extremity (7%), neck (4%), and head (4%). The most common injury was a ventricular stab wound (30%), followed by a gunshot wound to the lung (16%); 9% of survivors sustained blunt trauma, 34% underwent prehospital cardiopulmonary resuscitation (CPR), and the presenting base deficit was >25 mequiv/L in 18%. Relevant to futile care, there were survivors of blunt torso injuries with CPR up to 9 minutes and penetrating torso wounds up to 15 minutes. Asystole was documented at ED arrival in seven patients (12%); all these patients had pericardial tamponade and three (43%) had good functional neurologic recovery at hospital discharge.
CONCLUSION: Resuscitative thoracotomy in the ED can be considered futile care when (a) prehospital CPR exceeds 10 minutes after blunt trauma without a response, (b) prehospital CPR exceeds 15 minutes after penetrating trauma without a response, and (c) asystole is the presenting rhythm and there is no pericardial tamponade.
Defining the Limits of Resuscitative Emergency Department Thoracotomy: A Contemporary Western Trauma Association Perspective
J Trauma. 2011 Feb;70(2):334-339.

Difficult tube – Easytube

French pre-hospital physicians included the Easytube, which is similar to the Combitube, in their difficult airway algorithm. They describe the insertion method as:
..inserted blindly, the patient’s head must be in neutral position. Manually opening the patient’s mouth and pressing the tongue gently toward the mandible, the tube is inserted parallel to the frontal axis of the patient until the proximal black ring mark is positioned at the level of the incisors. If the EzT is inserted blindly, the tip is likely to be positioned in the esophagus with a probability of more than 95% [3]. Ventilation of the patient should be performed using a colored lumen, and the transparent lumen can then be used to insert a gastric tube or to drain gastric contents.
The authors suggest that the main advantages of the Ezt are: shorter insertion time for Ezt than for ETI, better protection against aspiration than a laryngeal mask and the possibility of blind insertion of the Ezt in patients trapped in a sitting position.
BACKGROUND: Securing the airway in emergency is among the key requirements of appropriate prehospital therapy. The Easytube (Ezt) is a relatively new device, which combines the advantages of both an infraglottic and supraglottic airway.
AIMS: Our goal was to evaluate the effectiveness and the safety of use of Ezt by emergency physicians in case of difficult airway management in a prehospital setting with minimal training.

METHODS: We performed a prospective multi-centre observational study of patients requiring airway management conducted in prehospital emergency medicine in France by 3 French mobile intensive care units from October 2007 to October 2008.
RESULTS: Data were available for 239 patients who needed airway management. Two groups were individualized: the “easy airway management” group (225 patients; 94%) and the “difficult airway management” group (14 patients; 6%). All patients had a successful airway management. The Ezt was used in eight men and six women; mean age was 64 years. It was used for ventilation for a maximum of 150 min and the mean time was 65 min. It was positioned successfully at first attempt, except for two patients, one needed an adjustment because of an air leak, and in the other patient the Ezt was replaced due to complete obstruction of the Ezt during bronchial suction.
CONCLUSION: The present study shows that emergency physicians in cases of difficult airway management can use the EzT safely and effectively with minimal training. Because of its very high success rate in ventilation, the possibility of blind intubation, the low failure rate after a short training period. It could be introduced in new guidelines to manage difficult airway in prehospital emergency.
The Easytube for airway management in prehospital emergency medicine
Resuscitation. 2010 Nov;81(11):1516-20

Pre-hospital Echo

Pre-hospital physicians in Germany performed basic echo on patients with symptoms either of profound hypotension and/or severe dyspnoea/tachypnoea where judged by the physician to be in a ‘peri-resuscitation’ state, and on patients undergoing CPR. Features noted were; cardiac motion (present or absent), ventricular function (normal, moderately impaired, severely impaired, absent), right ventricular dilatation or pericardial collection.
A few interesting findings to note:

  • In almost all patients an interpretable view was achieved; in the CPR patients, the subcostal view was best
  • In PEA patients, there was a difference in survival to admission (to discharge isn’t documented) between those with and without sonographically evident cardiac wall motion (21/38 = 55% vs 1/13 = 8%)
  • In ‘suspected asystole’, some patients had sonographically evident cardiac wall motion, and 9/37 (24%) of these survived to hospital admission vs 4/37 (11%) with no wall motion. On this point, the authors note: ‘The ECG performance and interpretation were by experienced practitioners, and this therefore raises questions regarding the accuracy of an ECG diagnosis of asystole in the pre-hospital setting‘.

Purpose of the study: Focused ultrasound is increasingly used in the emergency setting, with an ALS- compliant focused echocardiography algorithm proposed as an adjunct in peri-resuscitation care (FEEL). The purpose of this study was to evaluate the feasibility of FEEL in pre-hospital resuscitation, the incidence of potentially treatable conditions detected, and the influence on patient management.
Patients, materials and methods: A prospective observational study in a pre-hospital emergency setting in patients actively undergoing cardio-pulmonary resuscitation or in a shock state. The FEEL protocol was applied by trained emergency doctors, following which a standardised report sheet was completed, including echo findings and any echo-directed change in management. These reports were then analysed independently.
Results: A total of 230 patients were included, with 204 undergoing a FEEL examination during ongoing cardiac arrest (100) and in a shock state (104). Images of diagnostic quality were obtained in 96%. In 35% of those with an ECG diagnosis of asystole, and 58% of those with PEA, coordinated cardiac motion was detected, and associated with increased survival. Echocardiographic findings altered management in 78% of cases.
Conclusions: Application of ALS-compliant echocardiography in pre-hospital care is feasible, and alters diagnosis and management in a significant number of patients. Further research into its effect on patient outcomes is warranted.
Focused echocardiographic evaluation in life support and peri-resuscitation of
emergency patients: A prospective trial

Resuscitation. 2010 Nov;81(11):1527-33