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TRAUMA IN THE PICU. Pediatric Critical Care Medicine Emory University Children’s Healthcare of Atlanta. Epidemiology. #1 cause of death in > 1yr old Exceeds all other deaths combined 20,000/yr of children & teenagers 65% of all death <19 yrs old – unintentional injury
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TRAUMA IN THE PICU Pediatric Critical Care Medicine Emory University Children’s Healthcare of Atlanta
Epidemiology • #1 cause of death in > 1yr old • Exceeds all other deaths combined • 20,000/yr of children & teenagers • 65% of all death <19 yrs old – unintentional injury • 1 death from trauma 40 hospitalized 1,120 treated in ER • Most pediatric trauma are blunt injury (vs penetrating in adults) • More vulnerable to major abdominal injury from minor forces • More immature musculoskeletal system • Intra-abdominal organs are proportionally larger & closer together predisposed to multiple organ injury
Epidemiology • MVC – leading cause of death • ½ are unrestrained • 2/3 riding with drunk drivers • Pedestrian – leading cause of death in 5-9 yrs old • Bicycle injury increases with age – most common is head trauma
Physiologic Differences • Larger head greater inertia, movement & transfer of energy to the head & brain • Less soft tissue & muscle greater energy transfer to internal organs • Difference in center of gravity • Infant – above umbilicus • 1 yr – at the umbilicus • Adults – pubic symphysis • Jack knife effect with 2 points restraint spinal and intestinal injury in forward collision
Resuscitation • Causes of early death in injury • Airway compromise • Hypovolemic shock • CNS injury • ATLS : steps in trauma eval • Primary survey • Adjuncts to primary survey • Secondary survey • Adjunct to secondary survey (investigations) • Definitive managementss
Resuscitation – Primary Survey • A- Large head/occiput, large oropharyngeal soft tissue, short trachea frequent Right stem intubation • <12 yr: needle cricothyroidotomy because cricoid cartilage is the major support structure of airway • Surgical tracheostomy <12 yr • B – Pneumothorax, tension pneumothorax, hemothorax • C – Normal physiologic status up to 30% loss of total blood vol; traumatic cardiac arrest or penetrating with witnessed arrest poor outcome • D – Disability: CNS injury • E – Exposure: prevent further heat loss
Resuscitation – Secondary Survey • Similar steps as primary survey
Resuscitation – Investigations • Plain X-rays • Lateral C-spine: screen but not adequate in diagnosis • Supine chest: pulmonary of mediastinal injuries, not good in diagnosing small pneumothoraces • Pelvic: major pelvic disruption • Ultra sound • FAST: focused abdominal sonography for trauma, not very reliable in children as in adults • CT: • Chest abd. pelvis as indicated by injury
Trauma In PICU • Child abuse & neglect • Head injury • Spinal cord injury • Thoracic injury • Abdominal injury
Child Abuse & Neglect • Abuse head trauma: most common in PICU causing more long term morbidity • Neck is weaker with larger head larger CSF volume (move around), larger water contents increase in deformability • More rotational : tear bridging veins (SDH) & axons (DAI) • Neurons and axons – less protected due to less myelination • Skeletal injury: posterior rib fractures, metaphyseal fracture, spinous process fractures
Child Abuse & Neglect • Abdominal trauma: 2nd leading cause of fatal injury, 40%-50% death rates • Compression: crush solid viscera against anterior spine burst injuries to solid viscera & perforation of hollow viscera • Deceleration forces shear injuries at the site of fixed, ligamentous attachment with tear & hematoma formation • Thermal burns • Uniformed thickness – closely replicate the objects • Abuse scald burns – immersion pattern with circumferential & uniform depth, well defined edges, spares body creases
Severe Traumatic Brain Injury • Statistic230/100,000 • 3000-4000 deaths/yr; 10-15% are severe with GCS<8 deaths or permanent brain damage • 0-4 yr: worse outcome probably secondary to non-accidental trauma • 5-15 yr: favorable outcome compared to adults • Goals: to prevent secondary injury • Optimize substrate delivery & cerebral metabolism • Prevent herniation • Target specific mechanisms involved in the evolution of secondary injuries
TBI - Pathophysiology • Primary – direct disruption of brain parenchyma • Secondary – cascade of biochemicals, cellular amd molecular events • Ischemia/excitotoxicity, energy failure cell deaths • Secondary cerebral swelling • Axonal injury
TBI – Secondary Injury • Post-traumatic ischemia • Extra cerebral insults – hypotension/hypoxemia • Early hypoperfusion are common” CBF <20ml/kg/min associated with poor outcome • CBF recovered usually after 24 hrs • Delayed in normalization of CBF does not associated with poor outcome
TBI – Secondary Injury • Excitotoxicity • Glutamate & excitatory amino acid neuronal damage • 1st phase: Na dependent neuronal swelling • 2nd: Ca dependent degeneration DNA damage DNA repair Deplete ATP metabolic failure & necrotic cell deaths • CSF glutamate increases 5 folds in TBI in adults; increase of glutamate correlates with poor outcome • Tx with anti-exitatory MK-801 (NMDA antagonist); other txs- magnesium, glycine site antagonists, hypothermia, pentobarb • NMDA antagonists may induce apoptotic neurodegeneration in children
TBI – Secondary Injury • Cerebral swelling: initial min to hrs of post-traumatic hypoperfusion & hypermetabolism metabolic depression (CMRO2 decreases by 1/3 of normal) • Edema • Vasogenic & BBB disruption • Cellular swelling: astrocytes swelling – uptake of glutamate
TBI – ICP Monitoring • Parenchymal fiberoptic & microtransducer system • Subarachnoid, subdural, epidural- less reliable • Ventricular- best monitoring with benefit of draining CSF • Keep ICP <20 • Keep CPP 40-60 • 40-50: infants • 50-60: Children: • >60: adolescents • lidocaine: decrease catechol surge with direct laryngoscopy
TBI – Advanced Monitors • Stable Xenon CT CBF – monitor regional CBF • Stable Xenon technique • Transcranial doppler: measured velocity rather than flow, mainly MCA distribution • Jugular venous saturation: keep >50%, lower assoc. with mortality • NIRS- near infrared spectroscopy: trace the oxidative state of cytochrome, more on trends • PO2 microelectrode implantation to frontal parenchyma: also provide sign metabolic information: glutamate, lactic acid, glucose, ATP • PET: positron emission tomography
TBI – ICH Management • CSF drain • Osmolar therapy • Mannitol: • Rapid dec. ICP by dec. viscocity dec. bl vessel diameter. Depend on intact viscosity autoregulation. Transient (75 min) • Osmotic: (onset 15-30min; duration 1-6 hrs): water moves from parenchyma to circulation; work in intact BBB. May accummulate & worsen cerebral edema • Excreted unchanged in urine: may precipitate ATN & renal failure in dehydrated states. OK to use up to osmo of 365
TBI – ICH Management • Osmolar therapy Hypertonic saline: same benefits as mannitol • Other benefits: restoration of cell resting membrane potential, stimulation of atrial natriuretic epptide release; inhibition of inflamation; enhance cardiac performance • Side effects: extrapontine myelinosis: demyelination of thalamus, basal ganglia & cerebellum; SAH (tearing of bridging veins due to rapid shrinkage); renal failure; rebound ICU • Sedation, analgesia, NMB • Anticonvulsion: seizures cause inc. cerebral metabolic demands and release of excitatory amino acids • Head position • 30 degree: dec. ICP & mean carotid pressure with no change in CPP & CBF
TBI – ICH Management – 2nd tier • Barbiturates: dec. ICP via dec. CMR & CBV; direct neuroprotective effects by inhibiting free radical-mediated lipid peroxidation of membraned • Hypervent:dec. post-injury hyperemia & brain acidosis, restore CBF autoregulation • Prolonged hypervent: dec. brain interstitial bicarb buffering capacity, gradual dec. local vasoconstrictor effects • Hypothermia: 33 C • Hyperthermia exacerbates neuronal deaths • Decompression craniectomy • Lumbar CSF drainage • Controlled arterial hypertension
Acute Spinal Cord Injury • High cervical injury • C1-3 : infants/toddlers – MVC, trauma • C4-7 : Adolescents/adults – sport, MVC • Initial injury inc. in inflammatory cells & fibroblasts in cord tissue cellular necrosis • Release of lysosomal enzyme traumatic paralysis • “Spinal Shock”: high T or C injuries absence of sympathetic tone hypotension, bradycardia & hypothermia
Acute Spinal Cord Injury • Treatment • ABC • Methylprednisolone 30mg/kg bolus then 5.4 mg/kg/hr for 23 hrs; need to start bolus within 8 hrs of injury • Careful fluid management with pressors to improve vasodilatation • Osomotic diuretic to dec. secondary edema; low molecular weight of dextran to improve microcirculation • Hyperbaric oxygen therapy • Spinal cord cooling: need to be done within 4 hrs to 10 C • How long • How to deliver • What fluid • Technical difficulty
Acute Spinal Cord Injury • Sequelae • Respiratory failure: C3-5 innervation of diaphragm; CN IX innvervation to accessory muscle • UTI: neurogenic bladder, avoid overdistention and large volume residual, inc. risk of infection • Urolithiasis: immobility and hypercalcemia • Acute hypercalcemia due to immobility causing vomiting, polydipsia, polyuria, anorexia, nausea, malaise, listlessness
Thoracic Injury • 2:1 male to female • 92%: blunt trauma • 48% pulmonary contussion • 39% Pneumo/hemothoraces • 30% rib fractures • 33% in pediatric trauma fatality • Airway obstruction • Tension pneumothoraces • Massive hemothoraces • Cardiac tamponade
Thoracic Injury • Rib fractures • > 3 rib fx: reliable indication of intrathoracic or other organ involvements • Scapular or post rib fx – not associated with great vessels injury • Thoracic spine fx – inc. suspicion of great vessel injury • Pulmonary contussion • Absence of external signs: chest wall abrasion, tachypnea, abn. BS • Tx: fluid management, pulm. Toilet & respiratory support; corticosteroid is harmful
Thoracic Injury • Pneumo/hemothorax • Large bore in hemothorax to avoid fibrothorax & lung entrapment • CT: can cause exanguinating hemorrhage (intercostal, hilar or mediastinal vessel injuries) • Severe tracheobronchial disruption: high energy impact injuries, sub Q emphysema, dyspnea, sternal tenderness, hemoptysis. X-Ray: sub Q emphysema, pneumo-mediastinum, pneumothorax, air surrounding bronchus, abn. Appearance of ETT, collapsed of lung toward chest wall • Cardiac injury: 3%, most died at the scene • Myocardial contusion: act as MI or SVT & VT; min clinical significance, symptoms usually 12 hours post injury • Valvular dysfunction: papillary or chordae ruptures; • Cardiac rupture, pericarcial effusion, cardiac arrhythmias
Thoracic Injury • Aortic & great vessels injuries • Traumatic aortic disruption: mid scapular back pain, UE hypertension, dec. femoral pulses bilaterally, inc. CT output • X-Ray: widened mediastinum, deviation of NG or CVL, blurring of aortic knob, abn. paraspinous stripe, right tracheal deviation, upward shift of Left stem main bronchus • Others • Diaphragmatic ruptures: L>R • Esophageal rupture • Lung cysts
Abdominal Trauma • 83% blunt trauma • Solid organ injury: liver, spleen, kidneys 1- Spleen: extends below costal margin • grade I-IV, mainly observation • Surgical indication • Persistent hypotension or evidence of continuous hemorrhage • >50% blood volume replacement • Other life threatening associated intra-abdominal injury • I & II healed after 4 months • III-IV: healed after 6-11 months
Abdominal Trauma 2- Liver: also extends below the costal margin; associated with highest mortality May require surgical correction of injuries to the hepatic vein or vena cava associated with high mortality 3- Duodenum: Mostly hematoma, some with disruption of lumen Observation with TPN, bowel rest, resolution 2-4 weeks 4- Pancreas: - Operative repair depending on anatomy of injury & integrity of the main pancreatic duct - Upper abdominal pain, inc. amylase, edema of gland, fluid in the lesser sac - Fracture of pancreas when crossing over vertebral colume
Abdominal Trauma 6-Small bowel: Disruption, mesenteric avulsion, wall contussion More at fixation points: proximal jejunum at ligament of Treitz, terminal Ileum 7- Renal trauma: - Flank tenderness, mass or ecchymosis - Hematuria - Hematoma, laceration or vasular injury - Isolated urinary extravasation: not an emergent surg. Expl. - Need Abx - Renal pedicle injuries are rare - Ureteral injury – surgical repair
Abdominal Trauma 7- Blunt abdominal aortic injury: - Occur in high energy injury - Most common at inferior mesenteric artery or at the level of the kidneys - Major abdominal venous injuries are usually fatal
Abdominal Trauma 8- Bladder injury: mostly intra-abdominal - Burst injury - Rupture with pelvic fracture - Cystography: extra-peritoneal bladder rupture fluid extending superiorly and anteriorly to the level of umbilicus & by fluid in the retrorectal presacral space - Tx: depends on the location of injury: - extraperitoneal managed with catheter drainage alone; - penetrating or bladder neck injury or with vaginal/rectal injury required surgical repair
Abdominal Trauma 8- Bladder injury: mostly intra-abdominal - Burst injury - Rupture with pelvic fracture - Cystography: extra-peritoneal bladder rupture fluid extending superiorly and anteriorly to the level of umbilicus & by fluid in the retrorectal presacral space - Tx: depends on the location of injury: - extraperitoneal managed with catheter drainage alone; - penetrating or bladder neck injury or with vaginal/rectal injury required surgical repair
Abdominal Trauma 11- Pelvic fracture: - Single fracture of pubic ramus: rarely clinical significance - Multiple fractures: associated with significant intra-abdominal injuries - Sites of silent hemorrhage