Part 8: Emergency and Crit Care Flashcards
Children ____ have a higher % of injuries in the upper cervical spine than older children and adults
age
<9 y/o
In trauma, pts who have neurologic symptoms but no apparent abnormalities in CT or XRay may have…
Spinal cord injury without radiographic abnormalities (SCIWORA) - though most abnormalities may be detected by MRI
Severe spinal cord (C-spine) injuries will usually lead to ____ in pts who are breathing spontaneously.
Paradoxical Respiration - occurs when the diaphragm, which is innervated by the phrenic nerves with contributions from C3, C4, and C5, is functioning normally, but the intercostal musculature innervated by the thoracic spinal cord is paralyzed. In this situation, inspiration fails to expand of the chest wall but distends the abdomen.
Mildest injury to the spinal cord
Transient quadriparesis
- evident for seconds or minutes with complete recovery in 24 hr. This injury follows a concussion of the cord and is most frequently seen in adolescent athletes.
Significant spinal cord injury in the cervical region is characterized by
flaccid quadriparesis, loss of sphincter function, and a sensory level corresponding to the level of injury
An injury at this spinal cord level can cause respiratory arrest and death in the absence of ventilatory support
C1-C2
An thoracic injury at spinal cord level T10 or above may produce
paraplegia
An thoracic injury at spinal cord T12-L1 level may produce
Conus medullaris syndrome
- loss of urinary and rectal sphincter control
- flaccid weakness, and
- sensory disturbances of the legs
Higher risk wounds should be closed within _ hrs after injury, and low-risk wounds may be closed as late as _ ?
Time
6hours
12-24hrs
Parts of the intracranial dyanamics
Brain parenchyma ~85%
Blood
CSF
Further increases in ICP can ultimately displace the brain downward into the foramen magnum—a process called ?
Cerebral herniation
Increases in CSF pH that occur because of inadvertent hyperventilation (which decreases PaCO2) can produce?
Cerebral Ischemia
Hallmark of severe TBI
Coma (GCS 3-8)
Moderate TBI
GCS score
GCS 9-12
In the comatose child with severe TBI, the second key clinical manifestation is the development of ?
Intracranial HTN
The development of increased ICP with impending herniation may be heralded by
- new-onset or worsening headache,
- depressed level of consciousness,
- vital sign changes (hypertension, bradycardia, irregular respirations), and
- signs of 6th (lateral rectus palsy) or 3rd (anisocoria [dilated pupil], ptosis, down- and-out position of globe as a result of rectus muscle palsies) cranial nerve compression.
Significantly raised ICP (>20 mm Hg) can occur early after severe TBI, but peak ICP generally is seen at _ hr.
48-72 hr
Fluid of choice for pts with severe TBI
Normal saline
Treatment for cerebral herniation
- hyperventilate, with a fraction of inspired oxygen of 1.0, and
- intubating doses of either thiopental or pentobarbital, and
- either mannitol (0.25-1.0 g/kg IV) or hypertonic saline (3% solution, 5-10 mL/kg IV).
Age-dependent cerebral perfusion targets:
- 2 - 6 y/o: 50mmHg
- 7 - 10 y/o: 55mmHg
- 11 - 16 y/o: 60 mmHg
First-tier therapy for the management of increased ICP
- elevation of the head of the bed, ensuring midline positioning of the head, controlled mechanical ventilation, and analgesia and sedation (i.e., narcotics and benzodiazepines)
- osmolar agents hypertonic saline (often given as a continuous infusion of 3% saline at 0.1-1.0 mL/kg/hr) and mannitol (0.25-1.0 g/ kg IV over 20 min), given in response to ICP spikes >20 mm Hg or with a fixed (every 4-6 hr) dosing interval.
Second tier therapy for refractory increased ICP
- Barbiturate infusion
- Decompressive craniectomy
- Mild hypothermia (32-34oC)
- Hyperventilation (PaCO2 25-30 mm Hg)
- Lumbar CSF drainage
3 components for determining brain death
- Demonstration of co-existing irreversible coma with a known cause
- absence of brainstem reflexes
- apnea
True or False
The presence of spinal cord reflexes—even complex reflexes—does not preclude the diagnosis of brain death.
True
Apnea is defined as absence of respiratory effort in response to an adequate stimulus. PaCO2 value >= _ and _ above baseline is sufficient stimulus
60mmHg
20mmHg
Brainstem reflex tests to determine brain death
- Pupillary Light reflex (CN II, II, midbrain)
- Oculocephalic reflex (Doll’s eyes reflex; CN III, VI, VIII, midbrain, pons)
- Corneal reflex (CN III, V, VII, pons)
- Oculovestibular reflex (CN III, IV, VI, VIII, pons, midbrain)
- Gag and cough reflex (CN IX, X, medulla)
The most common cause of syncope in the normal pediatric population
Neurocardiogenic syncope (vasovagal syncope, fainting)
A phenomenon that can lead to syncope, but is usually very short, usually 30-60 secs, and occurs primarily with active standing, not passive upright tilt. BP may drop 30% of baseline at 10-20 sec of standing and may be assoc with tachycardia
Initial orthostatic hypotension
-usually happens after prolonged recumbence and when the individual stands
Define orthostatic hypotension
SUSTAINED decrease in the systolic BP of > 20mmHg or diastolic BP >10mmHg in the first 3mins upright
Rarely occurs in children
This is defined as relatively sudden change in autonomic nervous system activity that leads to a sudden decrease in BP, HR, and cerebral perfusion
Reflex syncope (vasovagal or neurally mediated)
In children, Postural Orthostatic Tachycardia Syndrome (POTS) is characterized by HR increase of __ beats/min during the 1st 10 min of upright tilt test without associated hypotension, (__ beats/min if >19 yr old) while replicating orthostatic symptoms that occur when upright. Improvement of symptoms in the supine position is expected.
> 40 bpm in children, >30 bpm if >19y/o
The diagnosis of POTS also requires daily orthostatic symptoms. In patients with POTS, the larger decline in cardiac stroke volume
Enumerate the various pathophysiologic mechanisms of POTS (4)
- Neuropathic POTS, an autonomic neuropathy impairing sympathetic venoconstriction in the lower extremities or splanchnic circulation, decreasing stroke volume, and consequently resulting in a tachycardia
- Hypovolemic POTS, a common contributor, often related to decreased aldosterone with reduced renin activity, resulting in a tachycardia caused by decrease blood volume
- Hyperadrenergic POTS, with norepinephrine levels rising 3-4–fold in the standing position (norepinephrine normally doubles on stand- ing), which may occur in norepinephrine transporter deficiency or strong stimulation of central baroreflex responses
- Autoimmune POTS, typically assumed based on a postviral chronology, but seldom proven; such a form may or may not exist.
The best measure for treating POTS
REgular aerobic exercise program
This is defined as any alteration of organ function that requires medical support for maintenance,
Multiple-organ dysfunction syndrome
This type of shock results from decreased cardiac output secondary to direct impediment to right- or left-sided heart outflow or restriction of all cardiac chambers
Obstructive Shock. Possible etiologies include: Tension pneumothorax Pericardial tamponade Pulmonary embolism
Anterior mediastinal
masses
Critical coarctation of aorta
Shock caused by inadequate vasomotor tone, which leads to capillary leak and maldistribution of fluid into the interstitium
Distributive shock. Possible etiologies: Anaphylaxis Neurologic: loss of
sympathetic vascular tone secondary to spinal cord or brainstem injury
Drugs
Criteria for CVS organ dysfunction
- Despite administration of isotonic intravenous fluid bolus ≥60 mL/kg in 1 hr: decrease in BP (hypotension) systolic BP <90 mm Hg, mean arterial pressure <70 mm Hg, <5th percentile for age, or systolic BP <2 SD below normal for age, or
- Need for vasoactive drug to maintain BP in normal range (dopamine >5 μg/kg/min or dobutamine, epinephrine, or norepinephrine at any dose), or
- Two of the following:
Unexplained metabolic acidosis: base deficit >5.0 mEq/L
Increased arterial lactate: >1 mmol/L or >2× upper limit of normal
Oliguria: urine output <0.5 mL/kg/hr
Prolonged capillary refill: >5 sec
Core-to-peripheral temperature gap: >3°C (5.4°F)
Criteria for Respiratory Organ dysfunction
- PaO2/FIO2 ratio <300 in absence of cyanotic heart disease or preexisting lung disease, or
- PaCO2 >65 torr or 20 mm Hg over baseline PaCO2, or
- Need for >50% FIO2 to maintain saturation ≥92%, or
- Need for nonelective invasive or noninvasive mechanical ventilation
Criteria for Neurologic organ dysfunction
- GCS score ≤11, or
- Acute change in mental status with decrease in GCS score ≥3 points from abnormal baseline
Criteria for Hematologic organ dysfunction
- Platelet count <100,000/mm3 or decline of 50% in platelet count from highest value recorded over last 3 days (for patients with chronic hematologic or oncologic disorders), or
- INR >1.5, or
- Activated prothrombin time >60 sec
Criteria for REnal dysfunction
- Serum creatinine >0.5 mg/dL, ≥2× upper limit of normal for age, or
- 2-fold increase in baseline creatinine value
Criteria for hepatic dysfunction
- Total bilirubin ≥4 mg/dL (not applicable for newborn)
- Alanine transaminase level 2× upper limit of normal for age
Septic shock is a combination of which types of shock?
Hypovolemic shock from intravascular fluid losses occurs through capillary leak. Cardiogenic shock results from the myocardial-depressant effects of sepsis, and distributive shock is the result of decreased SVR.
What is an inflammatory cascade that is initiated by the host response to an infectious or noninfectious trigger?
systemic inflammatory response syndrome (SIRS)
This inflammatory cascade is triggered when the host defense system does not adequately recognize and/or eliminate the triggering event. The inflammatory cascade initiated by shock can lead to hypovolemia, cardiac and vascular failure, acute respiratory distress syndrome (ARDS), insulin resistance, decreased cytochrome P450 activity (decreased steroid synthesis), coagulopathy, and unresolved or secondary infection.
What are some examples of proinflammatory mediators?
IL-6, IL-10, interferon-γ, and macrophage migration inhibitory factor
What are some examples of anti-inflammatory mediators?
IL-10, transforming growth factor-β, and IL-4.
Hallmark of uncompensated shock
Imbalance between oxygen delivery and oxygen consumption.
Elevated levels of this reflect poor tissue oxygen delivery noted in all forms of shock
Blood lactate
Target blood sugar level in patients with septic shock
RBS <= 180mg/dl
In the surviving sepsis campaign care bundles, what must be completed within the first 3 hours? (4)
- measure lactate level
- obtain blood cultures before administration of antibiotics
- Administer broad-spectrum antibiotics
- Administer 30 mL/kg crystalloid for hypotension or lactate
≥4 mmol/L.
Treatment of choice for anaphlaxis
Epinephrine
Amount of fluid boluses to be given in pts with cardiogenic shock
5-10ml/kg
An inodilator, this drug may improve systolic function and decrease SVR w/o causing a significant increase in HR and has the added benefit of enhancing diastolic relaxation
Milrinone
Drugs that improve BP that should generally be avoided in pts with cardiogenic shock
Agents that improve BP by increasing SVR (and therefore increased afterload) e.g., norepinephrine and vasopressin
What may be considered to be given in pts with shock that is unresponsive to fluid resuscitation and catecholamines?
Corticosteroids
What can be used if shock remains refractory despite maximal therapeutic interventions?
Mechanical support with ECMO
This is defined as inability of the lungs to provide sufficient oxygen (hypoxic respiratory failure) or remove carbon dioxide (ventilator failure) to meet metabolic demands.
Respiratory failure
Lesions in these parts of the brain result in hyperpnea and tachypnea
Cerebral hemispheres, midbrain
This is characterized by alternate periods of rapid and slow breathing
Cheyne-Stokes breathing. - may result from lesions in the midbrain