Grand Rounds Recap 8.1.18

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sports medicine - venous air embolism - neonatal shock- global health - snake & marine envenomations - dive medicine

Discharge, transfer, or admit : orthopedic injuries WITH Dr. bret Betz

Most orthopedic injuries seen in the Emergency Department require stabilization with likely follow up by an orthopedic surgeon.
There can be a lot of practice variation between orthopedic surgeons based on sub-speciality training and practice location.

Common Indications for Admission or Transfer

  • Concomitant vascular injury or infection
  • Multiple orthopedic injuries
  • Need for monitoring for compartment syndrome
  • Uncontrolled pain
  • Certain social situations that could impede patient's ability to follow up in clinic (i.e. psychiatric conditions, lack of access to transportation)

Case #1
A 23 yo football player is tackled by a much larger player who ends up landing on top of him.  Patient complains of shoulder pain and neck pain.  He is placed in cervical and spine precautions and brought to a local community hospital.

Vital Signs are stable.  Exam is notable for C4-C6 spinal tenderness and left shoulder pain to palpation. The patient is neurovascularly intact in his bilateral upper extremities.

X-ray of the left shoulder and chest are unremarkable.  Chest CT shows a posterior sternoclavicular dislocation with mediastinal hematoma with possible arterial extravasation.

Management:  Transfer to a level 1 trauma center via aeromedical transport emergently.  Patient required closed reduction in the OR with vascular surgery involved.

Sternoclavicular Dislocations

  • Rare.  Representing only 3% of dislocations around the shoulder
  • Esophageal, tracheal, or neurovascular injury occur in approx 30% of SC dislocations
  • CXR is often normal.  Test of choice is a CT chest with IV contrast.

Case #2
A 30 yo female is the driver in a head-on motor vehicle collision.  She complains of hip pain, lumbar back pain and is brought via EMS to a local community hospital.

Vital Signs are stable.  Exam is notable for pain to palpation along the lumbar spine and left hip.

Pelvic Xray shows a left nondisplaced pubic ramus fracture and CT lumbar spine shows a nondisplaced S1 sacral fracture.  All other CT imaging is negative for injury.

Management: Discharge, weight bearing as tolerated.

Pelvic Fractures

  • 60% of cases are from MVCs, 30% falls from height, and 10% crush injuries
  • The pelvic ring is made up of a posterior arch and anterior arch
  • Fracture displacement requires disruption at two or more places
  • Disruption of the SI joint requires a significant force and should prompt consideration of additional injuries

Case #3

62 yo female with history of osteoporosis presents to a local community hospital after a mechanical fall with right hip pain.

Vital signs are stable.  Exam is notable for a right lower extremity that is shortened and externally rotated and is neurovascularly intact. 

Right hip Xray/CT pelvis shows an anterior acetabular fracture with anterior hip dislocation

Management: Reduction of hip dislocation, placement of a knee immobilizer, transfer to a level 1 trauma center

Acetabular Fractures

  • Relatively uncommon
  • The acetabulum is the weight bearing portion of the pelvis
  • Almost all acetabular fractures are operative
  • Usually requires a complex surgery and is considered high risk.  Almost exclusively performed at tertiary/quaternary hospitals.
  • High risk of subsequent development of OA

Hip Dislocations

  • Reported 5-40% complication rate of avascular necrosis
  • AVN results from decreased blood flow to the femoral head after disruption of its vascular supply when the dislocation occurs
  • AVN occurs 2-5 years after hip dislocation
  • AVN risk reduced to <10% if reduction is performed in less than 6 hours

Case #4

28 year old female presents 3 days after a fall while walking up a flight of stairs.  She describes striking both of her knees against one of the steps.  She has bilateral knee pain, left greater than right.

Vital signs are stable. Exam is notable for tenderness to palpation over medial aspect of the left knee.  No laxity of the left knee with applied varus or valgus stress.  Patient is unable to extend her left knee.

Xray of the left knee shows no abnormalities.  CT of the left knee shows a quadriceps tendon rupture.

Management: Placement in a knee immobilizer, close follow up with subsequent surgery 

Quadriceps Tendon Rupture

  • Much more common than patellar tendon rupture
  • Usually occurs in patients >40 years old
  • Inability to extend the knee should prompt consideration of this diagnosis
  • Patella baja (low-riding patella) can be indicative of this injury

Case #5
19 year old male presents to a local community hospital with left knee pain and swelling after being tackled while playing football.  

Vital Signs are stable.  Exam is notable for a moderate left knee effusion without deformity, laxity about the knee with applied varus stress with the lower extremity at 0 degrees, tenderness to palpation in the popliteal fossa, numbness in the peroneal distribution, and abnormal ABI in the left lower extremity.

CTA of the left knee shows injury to the popliteal artery but no fracture.

Management: Placement of a knee immobilizer, transfer to a tertiary care center with orthopedic and vascular services available.

Knee Dislocations

  • Approximately 50% spontaneously reduce by the time of arrival to the ED.  
  • LCL laxity at full extension (0 degrees), effusion, peroneal numbness, abnormal ABIs are all major signs of this type of injury
  • Evaluation for arterial injury is very important.  ABIs are helpful in assessment even with palpable pulses.  If ABIs are abnormal consider urgent CTA
  • A patient with normal ABI/CTA of the knee and adequate pain control can be considered for discharge with a knee immobilizer.  Concern for vascular injury should prompt urgent transfer to a center with vascular surgery capabilities

r4 Case follow up:  venous air embolism WITH DR. jessica baez

A young female with a history of chronic pancreatitis s/p total pancreatectomy, DM, and chronic TPN through an internal jugular catheter presents to the ED with sudden onset of severe right sided chest pain and shortness of breath.  

Initial vital signs show tachycardia, mild hypertension, tachypnea, and hypoxia (65%) on room air.

She is rapidly placed on a non-rebreather mask with improvement in SpO2 to 80%.  Escalated to BiPAP with stabalization of SpO2 >94%.

Rapid bedside ultrasound shows no evidence for pneumothorax.  CXR shows mild bibasilar pulmonary edema that did not clinically correlate with the extent of her hypoxia.  EKG showed sinus tachycardia but otherwise was unremarkable.  

Nurses were unable to establish peripheral access despite multiple attempts.  Decision was made to draw labs from the IJ central line the patient presented with.  When attempting to draw blood from this line they got only return of air into the syringe.  Further inspection of the line revealed a small crack.  

A new central line was placed and the ED labs were remarkable only for a luekocytosis of 31.  Patient was sent for a CTPA which was negative for PE but did show findings consistent with ARDS.  Patient was admitted to the ICU, diagnosed with having a venous air embolism as complication of the disruption in her pre-hospital internal jugular central line.  Patient did well in hospital and was ultimately discharged 4 days later in good condition.

Venous Air Embolism

  • Requires a pressure gradient between the surrounding air and the vasculature to allow for air to enter
  • Most common causes are trauma (head/neck), postive pressure ventilation, CVC placement, scuba diving, surgery (ENT/NSGY)
  • Incidence reported between 1/47 to 1/3000 CVC placements
  • 20% mortality when clinically apparent

Clinical Presentation

  • Most are subclinical due to the body just reabsorbing the air
  • Can present with shortness of breath, chest pain, and/or hypoxia due to pulmonary vasoconstriction and endothelial damage.
  • 'Air Lock' is a phenomenon where a large venous air embolism obstructs the right ventricular outflow tract leading to profound hemodynamic collapse and death

Diagnosis

  • Difficult to diagnosis.  Must maintain a high level of suspiscion based on clinical context such as sudden onset of symptoms after placement of a CVC or ENT surgery.
  • EKG often will show sinus tachycardia with possible right heart strain pattern
  • Labs are usually less helpful but you can see an elevated CK and thrombocytopenia
  • TEE, in some cases, may show air bubbles within the heart 

Management

  • Mostly supportive care
  • High flow supplemental oxygen
  • Consider placing patient in the left lateral decubitus position
  • In severe cases can consider hyperbaric oxygen therapy or "closed chest cardiac massage" (CPR with a pulse to attempt to dislodge an air embolism causing air lock)

R3 taming the SRU: Neonatal shock WITH DR. susan owens

A 10 day old female arrives at a pediatric community emergency department as a transfer from her pediatricians office for tachycardia.

Patient is stated to be full term, no pregnancy or delivery complications, and was otherwise doing well until 2 days ago when she developed vomiting, lethargy, and was no longer tolerating feeds.

Upon arrival patient was observed to be cyanotic and minimally responsive and was immediatly transferred to the resusictation bay.

Initial vital signs showed tachycardia, hypotension, and they were unable to acquire an oxygen saturation despite multiple attempts.  Initial attempts at peripheral IV placement were unsuccessful and an IO was placed.  She was administered 2x 20cc/kg NS bolus, D10 for a heel stick glucose of 36, and antibiotics. 

The patient subsequently went into cardiac arrest.  She was emergently intubated and achieved multiple rounds of brief ROSC following epinephrine administration.  An epinephrine drip was intiated and the patient was also administered prostaglandins.  Persistent ROSC was then achieved.  Patient was subsequently transferred to a tertiary pediatric care center for post ROSC management by aeromedical transport.

During her ICU stay the patient was discovered to have an aortic coarctation for which she underwent thoracotomy with repair.  She was then discharged from the hospital 20 days later in good condition.

Neonatal Shock

Differential Diagnosis

  • Sepsis and ductal dependent heart lesions are the two most common causes of shock in a patient less than 30 days old
  • THE MISFITS mnemonic
    • Trauma, tumor, thermal
    • Heart disease, hypovolemia, hypoxia
    • Endocrine (CAH, DM, thyroid)
    • Metabolic disturbances (electrolyte imbalance)
    • Inborn errors of metabolism
    • Seizures or CNS abnormalities
    • Formula dilution 
    • Intestinal catastrophe (intussusception, volvulus, NEC)
    • Toxins 
    • Sepsis

Management

  • Obtaining Access
    • Consider rapid placement of a distal femur or tibia IO instead of troubleshooting peripheral IV placement
    • If patient is less than 4 days old consider umbilical vein access
  • Fluids and Pressors
    • Start with a 20cc/kg bolus 
    • If after 40cc/kg bolus there is minimal or no response consider rapid advancement to pressors
    • If after 60cc/kg bolus consider intubation and more aggressive pressor management
  • Hypoglycemia
    • Quickly obtain a blood glucose level (consider heel stick)
    • Replete glucose for blood concentrations < 40 mg/dl in term neonates and < 30 in preterm neonates
    • Administer 2-4 ml/kg D10 and recheck frequently to ensure euglycemia
  • Airway Management
    • For intubation consider a Phillips or Miller blade to counteract the "floppy" epiglottis
    • Consider pretreatment with atropine and at minimum have IV fluids and/or push-dose epinephrine ready as these patients have a high risk for peri-intubation cardiac arrest
    • Ketamine is the drug of choice for induction

Aortic Coarctation

  • Accounts for 7% of all congenital heart defects
  • Most frequently missed of the congenital heart defects
  • This is a ductal-dependent lesion.  Patients are often asymptomatic while the PDA is open but will start to manifest symptoms as early as day 2-5 of life when the duct starts to close
  • Have a high clinical suspicion if there is a discrepancy between carotid/upper extremity pulses and femoral/lower extremity pulses
  • Administration of prostaglandins serves to dilate the ductus arteriosis thereby allowing bypass of the obstruction to blood flow  

Global health grand rounds : operating internationally  WITH DR. christina williams

Global Need for Surgical Interventions

  • An estimated 4500-5000 operations are needed per 100,000 people worldwide
  • Estimated you would need 7 surgeons, each performing 643 surgeries per year, for every 100,000 people to meet this need
  • For comparison there are approximately 5.8 surgeons/100,000 people in the United States

Common Methods of Providing Global Health Surgery

  • Surgeons will travel to an area in need and provide surgical interventions for a defined amount of time without definitive plans to return to that area.  (Ex. Operation Smile)
  • Surgeons choose a location/community and establish a persistent location where they can provide surgical interventions year-round. (Ex. Cincinnati Surgical Outreach in Malowi)
  • Surgeons respond to areas with an emergent need to provide surgical interventions as part of the relief efforts in parts of the world experiencing an acute crisis.  (Ex. Doctors without Borders)

Challenges Facing Global Health Surgeons

  • Surgeons are often tasked with performing procedures that are outside of their typical scope of practice within the United States such as dental extractions, circumcisions, c-sections, and suprapubic catheters. 
  • Diagnostic modalities are often extremely limited.  
  • Limited access to blood products due to the logistical challenges but also in some cases due to cultural barriers
  • Limited access to ventilators which means patients must be ready for extubation at the end of the surgery
  • Limited access to anesthetic medications

Wilderness medicine : venomous snakebites and Marine envenomations in the us WITH DR. mel otten

Toxinology

  • Study of naturally occurring toxins
  • Poisonous organisms are assimilated into another organism either by ingestion or through the skin.  Ex. bacteria, fungi, plants, some animals
  • Venomous organisms have evolved a specific toxin delivery system.  Ex. venom glands, stings, spines, fangs, pores. 

Epidemiology of Snake Envenomation

  • 6000 reported bites resulting in 3-5 deaths by indigenous venomous snakes in the US per year
  • 2.5 million reported bites resulting in 125,000 deaths worldwide per year
  • Males 17-27 are most commonly bitten
  • Most occur April - December
  • Alcohol use is often involved
  • Most bites are due to deliberate exposure rather than a surprise bite while outdoors

Venomous Snakes

  • 3000 species of snakes and only 15% are dangerous to humans
  • Venomous families: Elapidae, Viperidae, Hydrophidae, Crotalidae, and Colubridae
  • Crotalidae
    • Includes rattlesnakes, copperheads, water moccasins, and pygmy rattlesnakes
    • Have small heat sensitive pit between the eye and nostril which helps them find prey and large mobile fangs
    • Venoms are widely varied complex protein mixtures.  They often cause local tissue necrosis as well as having both cardiotoxic and neurotoxic effects.
    • 25-35% of bites are "dry" where little to no venom is injected
    • Symptoms of pit viper bites:
      • Early: nausea, vomiting, perioral paresthesia, paresthesias of fingers and toes, lethargy, weakness, odd taste in mouth.
      • Late: Hypotension, tachypnea, respiratory distress, tachycardia, altered sensorium, coagulopathy
  • Elapidae
    • Includes cobras, mambas, kraits, and coral snakes
    • Only coral snakes are found in the US
    • Venoms are widely varied complex protein mixtures.  They often cause local tissue necrosis as well as having both cardiotoxic and neurotoxic effects.
    • You can differentiate a coral snake (venomous) from non-venomous variety of similarly colored snake by remembering "Red next to yellow, kill a fellow.  Red next to black, venom lack".  Just remember, this is only useful in the United States when trying to identify an eastern coral snake!  There are instances when this would not be true in other parts of the world! 

Management of Snake Bites

  • General Management
    • Consider airway management with bites to the face/neck
    • Fluid resuscitation
    • Analgesia
    • Local wound care
    • Tetanus prophylaxis 
  • Antivenom
    • Definitive therapy for snake envenomation
    • Imparts passive immunity to patient
    • Should be given as soon as possible
    • CroFab is most common antivenin and should be administered to any patient bitten by a North American pit viper with findings of local envenomation or evidence of systemic toxicity.  Dose for mild to moderate envenomation is 4-6 vials

Marine Envenomations

  • 2000 species of venomous marine animals
  • General management:
    • Remove from the water to prevent drowning
    • Local wound care
    • Administer a specific antivenom (if it one exists for the envenomation)
    • Be prepared to manage anaphylaxis 
  • Three mechanisms of envenomation: bites, nematocysts, and stings
     
  • Bites
    • Octopi:  tetrodotoxin venom can be lethal.  Typically only require local wound care
    • Seasnakes: 50 species, all of which are toxic and 7 are typically fatal.  Their fangs are short so most bites don't result in envenomation.  There is an antivenom available for many seasnake bites.
  • Nematocysts
    • Spring-loaded venom gland that everts and delivers venom
    • Remain functional even after animals death
    • May still be "loaded" without firing even if its in the skin
    • Management involves cutting off the tentacles, inactivate the nematocysts with hot water, vinegar, or bicarb, remove the nematocysts.  Antivenom only exists for box jellyfish 
    • Box jellyfish is the most deadly of all marine life.  One box jellyfish can kill 10 humans.  Cardio-respiratory collapse can occur within minutes.
  • Stings
    • Specialized apparatus that punctures skin and delivers venom
    • Management involves removing the stinger, irrigate copiously with HOT water.  The venom is heat-labile and hot water will inactivate it.
    • Antivenom exists for stonefish stings.

 wilderness medicine : dive medicine WITH DR. roche

There are two common dive related emergencies: barotrauma and decompression sickness

Barotrauma

  • Commonly seen with inexperienced divers involved in a shallow dive where they surface too fast.
  • Symptoms have rapid/immediate onset
  • Boyles Law simplified: Pressure makes bubbles smaller.  As patients descend bubbles within the sinuses, dental fillings, middle/inner ear, mask all get smaller.  As they proceed to ascend these bubbles will expand.  
  • Breath holding while ascending leads to alveolar rupture

Decompression Sickness

  • Commonly seen with commercial divers involved in a deep dive.
  • Symptom onset is within the first hour (50%) and majority will have onset within 6 hours.
  • Henry's Law simplified: Pressure puts bubbles in solution.  As patients descend the partial pressure of nitrogen in the blood increases and if they ascend too quickly the nitrogen can form bubbles in the tissues/blood stream leading to symptoms.  A slow ascent can prevent this by allowing more time for the nitrogen to exit the tissues and ultimately be exhaled without forming bubbles in the blood/tissues
  • Two Types:
    • Type I (MSK): joint pain, itchy skin rash
    • Type II (Systemic): arterial gas embolism, vague neuro manifestations, vertigo, pulmonary venous embolism, decompression shcok

Decompression Sickness Symptoms

  • "The Chokes" : pulmonary gas embolism
  • "The Creeps": skin gas bubbles
  • "The Staggers": semicircular canal bubbles
  • The Bends": joint bubbles

Management

  • Oxygen and supportive care
  • Aggressively hydrate with IV fluids
  • Hyperbaric therapy
    • Hyperbaric therapy allows for the big bubbles to shrink and allows for nitrogen to go back into solution where it can then be breathed off