Critical Care Flashcards
Abdominal Compartment Syndrome (ACS)
Background
Considerations
Goals/Conflicts
Background
Definition: sustained intraabdominal pressure >20 mmHg that is associated with new organ dysfunction
Patients with an intraabdominal pressure <10 mmHg generally do not have ACS, while patients with an intraabdominal pressure >25 mmHg usually have ACS
Higher systemic blood pressure will be needed to perfuse abdominal organs, keep abdominal perfusion pressure (APP) (systemic blood pressure - intraabdominal pressure) >60mmHg
Etiology:
Primary: due to injury or disease in the abdominopelvic region (e.g., pancreatitis, abdominal trauma)
Intervention (surgical or radiologic) of the primary condition is often needed
Secondary: does not originate in the abdomen or pelvis (e.g., fluid resuscitation, sepsis, burns)
Considerations
Critically ill patient with high mortality & morbidity
Multisystemic dysfunction:
Airway: ↑ risk of aspiration
CVS: ↓ cardiac output (CO) from ↓ preload & ↑ SVR
Resp: Hypoxia secondary to restrictive ventilation
Renal: Potential for AKI
GI: Hepatic dysfunction (altered pharmokinetics)
Need to maintain APP > 60 mmHg
Consequences of decompression:
Sudden ↓ in cardiac output & SVR
Reperfusion: risk of systemic acidosis & hyperkalemia
Possible fatal arrhythmia & arrest
Sudden change in respiratory compliance (avoid overventilation)
Goals/Conflicts
Early identification of ACS
Maintain APP >60mmHg
Avoid bradycardia (preload is compromised & CO may be heart rate dependent)
Maintain high preload particularly once decompressed
Be prepared for sudden arrhythmias associated with hyperkalemia & acidosis after decompression occurs
Acute Respiratory Distress Syndrome (ARDS)
Considerations
Goals
Berlin Definition of ARDS (JAMA 2012): All criteria must be present
Acute Respiratory Distress Syndrome (ARDS)
Considerations
Profound hypoxemic respiratory failure
Complications related to etiology of ARDS:
Sepsis/SIRS
Infection/aspiration
Trauma
Transfusions
Multi-organ system failure
Lung protective ventilation strategies:
Tidal volume: 6 mL/kg IBW (ideal body weight)
PEEP & FiO2 to avoid hypoxemia: goal PaO2 ~60 mmHg
Plateau pressure: goal < 30 cmH2O
Permissive hypercapnea
Therapies for refractory hypoxemia:
Optimize PEEP: esophageal pressure, PV curves, lung ultrasound
Consider paralysis
Advanced treatments: prone position, inhaled nitric oxide, high frequency oscillatory ventilation (HFOV), ECMO
Goals
Maintain oxygenation & end-organ perfusion
Avoid further lung injury by using lung protective ventilation strategy
Berlin Definition of ARDS (JAMA 2012): All criteria must be present
Respiratory symptoms must have begun within one week of a known clinical insult, or the patient must have new or worsening symptoms during the past week.
Bilateral opacities consistent with pulmonary edema present on a chest x-ray or CT scan. Opacities must not be fully explained by pleural effusions, lobar collapse, lung collapse, or pulmonary nodules.
The patient’s respiratory failure must not be fully explained by cardiac failure or fluid overload. An objective assessment (e.g., echocardiography) to exclude hydrostatic pulmonary edema is required if no risk factors for ARDS are present.
A moderate to severe impairment of oxygenation must be present, as defined by the ratio of arterial oxygen tension to fraction of inspired oxygen (PaO2/FiO2)
With ventilation & PEEP ≥5 cmH2O, the severity is defined as:
Mild ARDS: PaO2/FiO2 is 200 - 300 mmHg
Moderate ARDS: PaO2/FiO2 is 100 - 200 mmHg
Severe ARDS: PaO2/FiO2 is ≤100 mmHg
Burns
Considerations
Goals
Parkland Formula
Burns
Considerations
Trauma patient, ATLS approach
Difficult/threatened airway: edema, secretions, bleeding
Potential inhalational injury & carbon monoxide/cyanide poisoning
Hypovolemia & need for goal-directed volume resuscitation (e.g., Parkland, see below)
Multisystem dysfunction:
Acute:
Hypovolemic/cardiogenic shock/low cardiac output state → septic shock/high cardiac output state
Pulmonary edema/aspiration/restrictive lung
Hyperkalemia/myoglobinuria/AKI
DIC, anemia of burns
Impaired thermal regulation
Difficult monitoring/IV access (ECG patches, BP cuffs, etc)
Delayed:
Sepsis
DVT/PE
Stress ulcers, adynamic ileus, hypermetabolic/catabolic state
Pharmacologic changes: succinylcholine contraindication (>24 hours to 1year)/NDMR resistance (>60 days)
Complications of resuscitation:
Abdominal compartment syndrome
Fluid creep (pulmonary edema, venous congestion, graft dysfunction)
Frequent ORs (debridement/grafting):
Blood loss
Pain, opioid tolerance
Possible remote location
Goals
ATLS approach
Secure definitive airway (facial/neck/inhalational or major burn)
Assess burn severity/extent
Volume resuscitation (formula driven, goal directed)
Measure CO levels with co-oximetry
Prevent end-organ dysfunction (lung protective strategy if ARDS, urine output >1ml/kg/hr)
Adequate analgesia (multimodal approach +/- antidepressants)
Parkland Formula
4cc X %BSA X weight (kg)
E.g. 70kg patient with 20% burn
4cc X 20 X 70 = 5600cc
Total fluid for 24 hrs: 1/2 in first 8 hrs, 1/2 in next 16 hrs
Clinical end points:
Urine output >0.5cc/kg/hr
Follow HR/BP, goal MAP >60
Follow lactate/mixed venous
Crush injuries
Considerations
Goals
Crush Injuries
Considerations
Critically ill/trauma patient/ATLS
Co-existing traumatic injuries
Complications of rhabdomyolysis:
Hyperkalemia, hyperphosphatemia, hypocalcemia, anion-gap metabolic acidosis
Myoglobinuria & renal failure
DIC (rare, can happen with severe rhabdomyolysis)
Goals
ATLS resuscitation
Treat underlying condition
Prevention of hyperkalemia:
No succinylcholine
No potassium-containing fluids
Monitor K closely
Prevention of acute tubular necrosis (ATN):
Start with 2L bolus NS then, isotonic fluid at ~500 cc/hr for 24 hours titrated to urine output of 200-300 cc/hr
Alkaline therapy: 3 amps of HCO3- in 1L D5W at 2x maintainence titrated to urine pH > 6.5 (generally, a total of 200-300 mEq of bicarbonate is given on the first day)
Must monitor:
Serum bicarbonate/pH: do NOT allow serum pH >7.5
Calcium: severe hypocalcemia is a side-effect
Potassium
Urine pH
Mannitol 5 g/hr infusion for a total of 1-2g/kg per day maximum
Loop diuretics if volume overload
Drowning
Considerations
Goals/Conflicts
Treatment
Drowning
Considerations
Trauma/ATLS approach:
Possible C-spine injury
Hemorrhage/occult injuries
Co-ingestions
Hypothermia:
Coagulopathy
Arrhythmias
Hypovolemia
Rewarming technique
Electrolyte abnormalities
Multi-organ system dysfunction:
ARDS
Hypoxic brain injury
Electrolyte abnormalities (↑K+), cell lysis 2nd to fresh water drowning
Shock
ARF
Etiology of drowning:
Adults: arrhythmia (long QT syndrome), seizure, trauma, MI, intoxication
Children: abuse, unsupervision
Goals/Conflicts
Primary Resuscitation to ensure adequate oxygen exchange and perfusion pressure
Prevent secondary injury: C-spine precautions
Aggressive rewarming
100% mortality = Submersion > 25 min, Resuscitation > 25 min, Pulseless on arrival to ED, Unconscious at scene and on arrival to ED
Treatment
Treat hypoxia: restore oxygenation and ventilation
Rescue breaths
Endotracheal intubation
100% oxygen until ROSC then FiO2 to keep SpO2 > 92%
Treat cardiac arrest: may be PEA, systole, VT/VF
Follow ACLS guidelines
Modifications for hypothermia: active rewarming until 34ºC then passive
Consider 24 hours of therapeutic hypothermia (32-34ºC)
Cervical spine injury extremely rare (0.009%): do not place C-spine collar unless mechanism for C-spine injury is suggested
Organ Retrieval
Terminology
Considerations
Goals (Cardiac, Respiratory, Endocrine, MSK, Haematologic)
Organ Retrieval
Terminology
DBD: Donation after Brain Death:
At least 2 physicians NOT involved in organ procurement must declare brain death in accordance with the American Academy of Neurology guidelines; the anesthesiologist is NOT involved in this process
DCD: Donation after Cardiac Death:
A DCD donor does not meet the strict criteria for brain death but has suffered a severe non-recoverable brain insult & the family has decided to withdraw life support
Upon withdrawal of life support, the DCD donor’s death is declared based on cardiopulmonary criteria
After death is declared, 5 minutes must pass before organ procurement begins
Considerations for DBD
Confirm the diagnosis of brain death & confirm wishes of patient & family:
Declared by 2 physicians not involved with transplant
Minimum clinical criteria for brain death met (see guidelines)
Physiologic consequences of brain death:
Hemodynamic instability (myocardial dysfunction, vasomotor tone, hypovolemia)
Pulmonary dysfunction with ARDS & hypoxemia (neurogenic pulmonary edema, VAP, CHF, etc)
Neuroendocrine dysfunction
Diabetes insipidus (70%), hypernatremia, hypokalemia
Hypothyroid
Hypocortisolemia
Hyperglycemia
Coagulopathy/DIC (brain release of thromboplastin)
Poikilothermia secondary to hypothalamic dysfunction
Etiology of brain death & secondary injuries
Trauma (potential for multi-organ involvement, pulmonary/cardiac contusions)
Goals for DBD
Cardiac:
Ensure adequate intravascular volume
Use vasopressors to maintain adequate organ perfusion
Vasopressin as 1st line agent as it treats BP & diabetes insipidus (dose = 0.01-0.04 IU/min)
Norepinehrine & dopamine also reasonable agents
Avoid high doses of vasopressors
Hemodynamic goals are SBP >100 mmHg, MAP >70 mmHg, HR 60-120
Respiratory:
Lung protective ventilatory strategy: TV 6-8cc/kg, PEEP 8-10, avoid fluid overload, FiO2 <40% for lung retrieval
Endocrine:
Thyroid replacement: tetraiodothyronine 20 mcg IV bolus, then 10mcg/hr infusion
Vasopressin 1 U IV bolues, then 0.01-0.04 U/hr infusion
Methylprednisolone 15mg/kg IV q24h
Keep serum glucose <8 mMol/L
MSK: paralytics should be given during procurement to optimize surgical conditions & stop somatic response to surgical stimulus mediated by spinal cord reflexes
Hematologic:
Keep Hgb ~100
Platelets & FFP if clinical bleeding, do NOT simply correct abnormal coagulation tests
Sepsis
Considerations
Goals
Sepsis
Considerations
Critically ill patient, high mortality
Emergency surgery, possible full stomach
Distributive shock with severe hypovolemia:
Early goal-directed therapy & early antibiotics/source control required
Potential for cardiovascular collapse on induction
Need for invasive monitoring
Need for critical care monitoring/ICU postop
Multi-organ failure:
ARDS
AKI
DIC
Goals
Follow Surviving Sepsis Guidelines:
Broad spectrum antibiotics within 1 hour
Goal directed resuscitation within 6 hours:
MAP ≥ 65
Fluid therapy:
Use crystalloids as first line, avoid synthetic colloids, consider albumin if substantial amounts of crystalloids used
Initial fluid bolus = 30cc/kg, use dynamic or static variables to guide further fluid therapy
Vasopressors/inotropes:
Norepinehprine = 1st line
Epinephrine can be added as second vasopressor
Vasopressin NOT recommened alone, may be added as second or third agent
Dopamine not routinely recommended
Phenylephrine can be useful if excessive arrythmia from other vasopressor, very high cardiac output states, or as an adjunct vasopressor
Dobutamine as first line inotropic agent in settings of reduced cardiac output/low mixed venous/myocardial dysfunction
Urine output > 0.5 mL/kg/hr
Lactate < 2 mmol/L, clearance of lactate
Lung protective ventilation (Tidal volumes ~6cc/kg, plateau pressure <30cm H20, PEEP)
Corticosteriods:
NOT indicated if fluids/vasopressors have restored hemodynamics
Consider IV hydrocortisone 200mg daily if refractory shock
Hemoglobin: in absence of myocardial ischemia/ischemic heart disease, goal Hgb ≥70
*Note that routine monitoring of central venous pressure (CVP) or central venous oxygen saturation (ScvO2) are no longer recommended
Inhalational Injury
Considerations
Management
Inhalational Injury
Considerations
Emergency/full stomach
Airway swelling & potential for airway obstruction
Tracheobronchial thermal & chemical injury resulting in pulmonary complications:
Alveolar collapse/atelectasis & airway plugging
Bronchospasm
Pneumonia
ALI/ARDS
Carbon monoxide & cyanide poisoning
General burn considerations:
Hypovolemic shock
Hypo or hyperthermia
Rhabdomyolysis
Cardiac depression
DIC, consumptive coagulopathy
Management
Secure airway early if compromised
Bronchoscopy to document degree of tracheobronchial injury
Use lung protective ventilation strategies:
Tidal volume ≤ 6cc/kg
Plateau pressure < 30cm H2O
PEEP & FiO2 to achieve adequate oxygenation (PaO2 ≥55 to 80 mmHg)
Start burn resuscitation
Rule out & treat carbon monoxide & cyanide poisoning
ICU admission & monitoring
Trauma
Considerations
Pregnancy Considerations
Trauma
Considerations
Emergency/full stomach
Difficult airway due to C-spine injury/immobility
ATLS approach to resuscitation
Multiple obvious & occult injuries
Need for ongoing assessment & resuscitation
Hypovolemia, hypothermia, coagulopathy, acidosis
Potential toxic ingestions, uncooperative patient
Immediately life-threatening injuries:
Airway obstruction
Tension pneumothorax
Open pneumothorax
Cardiac tamponade
Massive hemothorax
Flail chest
Delayed/hidden injuries:
Thoracic aortic disruption
Tracheobronchial disruption
Myocardial contusion
Traumatic diaphragmatic tear
Esophageal disruption
Pulmonary contusion
Pregnancy Considerations
↑ risk of aspiration, difficult airway
Altered pattern of injury: preterm labour, abruption, uterine rupture, amniotic fluid embolism, alloimunization
Delayed decompensated shock secondary to physiologic changes: hypervolemic hemodilution
Altered ACLS:
IV above diaphragm
Chest compressions higher
Left uterine displacement
Stat cesarean section at 4 minutes post cardiac arrest
2 patients requiring:
Fetal monitoring
Obstetrics/pediatrics consults
Steroids for fetal lung maturity if <34 weeks GA
MgSO4 for fetal brain protection
Considerations RE: imaging (CT, X-ray)
