EMS Lecture: Double Defibrillation WITH DR. Curry
Double defibrillation surrounds off label use of a defibrillator. Recurrent is ventricular fibrillation (VF) is defined as VF that resumes after a period of conversion. Refractory is VF is defined as VF that does not respond to therapy, there is no true consensus of how many shocks defines refractory VF.
From the electrophysiology (EP) literature regarding internal defibrillators it is important to know that biphasic defibrillation uses less energy and first shock success rates 90%. Monophasic defibrillation uses more electrical energy, causes more trauma, more myocardial injury and has a 60% first shock success.
The evidence has shown that it is difficult to consistently deliver simulation defibrillation.
Overall the evidence shows that there are too many different ways that the therapies are applied to draw conclusions. For example, placement of defibrillation pads varies significantly between studies. This is important because the placement of defibrillation pads affects the vector of delivery of defibrillation.
There is a case report showing that double external defibrillation has caused damage to the defibrillator rendering it unable to deliver any electricity. This is because the machines are not designed for double defibrillation.
EP studies has shown that changing the vector of defibrillation can improve your likelihood of cardioversion out of VF. This is done by changing defibrillation pad location. Good pad contact is also important. Dr. Curry recommends starting with anterior-apex defibrillator placement as it does not require rolling the patient for pad placement, but to follow the directions of the particular manufacturer . Anterior-posterior pad placement is preferred for synchronized cardioversion. There are no EP studies that support one specific pad location over another for defibrillation for the treatment of VF.
Other Proven Interventions
There are some studies to suggest the idea of "priming the pump", which means to extend the period of continuous chest compressions in order to improve myocyte perfusion and ultimately increase myocyte ATP. This may make it more likely for the heart to respond to defibrillation to cardiovert out of VF. Besides electricity there are also options to try to convert out of VF. Medications, such as esmolol act to reduce adrenergic drive, ECMO, and cardiac catheterization with a Lucas device if an acute coronary ischemic etiology is suspected, although data on all of the above is needed.
Clinical Diagnostics: Pelvic Xray WITH DR. Mand
For a primer check out Dr. Mand's post here
Key physical exam maneuvers to preform to evaluate for an unstable pelvis include posterior pressure to the iliac crests, lateral to medial pressure to the iliac wings, and suprapubic pressure to the public symphysis.
Mortality is reported as 0.4-0.8% solely from pelvic fractures. Mortality from pelvic fractures increases with hemodynamic instability and bleeding from a venous source.
Physical exam findings that are concerning for an associated genitourinary injury in the setting of pelvic fracture are the presence of blood at the urethral meatus, perineal bruising, high-riding prostate, and rectal or vaginal perforation
In the pre-hospital setting, pelvic binders should be placed on trauma patients who have a suspicion for pelvic fracture and hemodynamic instability and GCS <15, pelvic pain, distracting injury. Pelvic binders should be placed flush against the skin, over the greater trochanters. This is important because over 50% of pre-hospital pelvic binders are misplaced and are often misplaced superiorly.
The purpose of the a pelvic binder is to decrease the pelvic volume, to stabilize clot formation, and to reduce ongoing tissue damage. When placed correctly, in the setting of an unstable pelvic fracture, a pelvic binder should improve hemodynamics and mechanical stabilization. However, studies have yet to show pelvic binders decreasing the need for transfusion or decreasing mortality.
As for the risk of pelvic binders, they are temporizing only and can cause soft tissue necrosis. They are also not definitive therapy such as external fixation, peritoneal packing, or embolization which is often required. There is also concern that in the setting of lateral pelvic compression injuries applying the pelvic binding over this injury can worsen the deformity. However, in the pre-hospital setting pelvic binders should continue to be placed based on the criteria described above. Once imaging is obtained and the type of pelvic injury is determines, providers can then assess the need for continued use of the pelvic binder.
Posterior hip dislocations commonly present as a shortened, internally rotated, and adducted lower extremity. Concerning complications associated with posterior hips dislocation are avascular necrosis and sciatic nerve injury. Posterior hip dislocations commonly occur from dashboard injuries. Presence of a femoral neck fracture is a contraindication to reduction of the hip.
Pediatric Hip Quick Hits
Legg-Calve-Perthes is a common cause of lip and hip pain in children aged 4-8 years old. Slipped capped femoral epiphysis (SCFE) most commonly presents in patients aged 10-14 years old complaining of hip pain, altered gait, or inability to bear weight. 20-40% of patients with SCFE have bilateral disease. Frog leg pelvic views should be obtained in addition to an AP pelvis. Patients with SCFE should be made non-weight bearing and require surgical pinning.
CPC: Brown-Sequard WITH DRs. Banning and Kreitzer
Brown-Sequard Syndrome (BSS) is characterized by weakness, loss of vibration and proprioception on the ipsilateral side of the injury and a loss of pain and temperature on the contralateral side of the injury. Patients often have upper motor neuron signs. BSS can be caused by a wide variety of etiologies but is most commonly from penetrating injuries or demyelinating disorders. Depending on the underlying etiology, patients can have a good prognosis
Spinal Cord Injury Management
Airway. Anyone with a complete cervical cord injury above C5 should be closely monitored for need for airway intervention. When intubating, cervical collar should be removed and manual in-line stabilization should be held. In the acute setting, especially in trauma patients, succinylcholine is safe to use as long as the injury is less than 48 hours old
Breathing. C3-C5 innervate the diaphragm, T1-T11 innervate the intercostal muscles which can play a role in ventilation as well.
Circulation. These patients can present with signs and symptoms of neurogenic shock such as hypotension and bradycardia. In the trauma setting this is a diagnosis of exclusion and providers should rule out other etiologies of shock such as hemorrhagic and obstructive. If you have made the diagnosis of neurogenic shock, norepinephrine is considered the initial pressor of choice as it will help with both the hypotension and bradycardia.
Steroids. Level 1 recommendation from the College of Neurosurgery states that the benefits of steroids in spinal cord injury DO NOT out weigh the risks.
Taming the SRU: pediatric Meningitis WITH DR. Liebman
Some studies suggest 1:500 rule (WBCs:RBCs) for adjusting leukocytes to RBCs in CSF.
Consider TB meningitis in patients with low glucose and low protein.
Pediatric Intubation During Cardiac Arrest
Studies suggest that there is some benefit to intubation during cardiac arrest but not difference in ROSC or neurologic outcomes.
EM-Pediatric Simulation and Clinical Cases
Pediatric Hypothermic Cardiac Arrest
When treating hypothermia as the etiology of cardiac arrest there are a few differences in how the arrest is managed as compared to a non-hypothermic arrest. It is recommended to preform less frequent dosing of epinephrine, spacing out administration to every 6-10 minutes as compared to every 3-5 minutes. As the child rewarms, you may see ventricular arrhythmias. This is treated with defibrillation, lidocaine, and amiodarone per PALS.
If you are treating a hypothermic arrest and you work at an ECMO center, ECMO is your best attempt at rewarming. Other high yield actions are warm, inhaled oxygen, warmed IV fluids, and removing cold, wet clothes.
In the setting of drowning as the etiology of cardiac arrest it is important to evaluate for traumatic causes of arrest as well as airway foreign body. The empiric placement of c-collar usually is not necessary without external evidence or other high suspicion of trauma.
Post-arrest hypothermia, induced after return after spontaneous circulation, studies have not show any benefit in neurologic outcomes.
Pediatric DKA Pearls
It is always important to consider DKA when evaluating the patient with isolated vomiting. The feared complication of pediatric DKA is cerebral edema, especially in patients under 5 years of age. Ways to combat iatrogenic cerebral edema include not bolusing insulin prior to starting a patient on an insulin drip and giving no more than one 20cc/kg fluid bolus prior to starting maintenance IV fluids. Headache is often the first sign of cerebral edema. It is important to start pediatric patients on dextrose containing fluids once their glucose <250 or if their glucose drops by more than 100/hour.
Cat Scratch Disease
Studies suggest that 50% of all cats are bacteremic with Bartonella at any give time! Providers can test for Bartonella infection with titers (IgG and IgM), cultures, or PCR. Pediatric patients typically present with a lesion at the site of the inoculation and then local lymphadenopathy as well as fever. Bartonella is a common cause of fever of unknown origin in the pediatric population. Azithromycin is first line treatment.