Approach to Critical Illness Flashcards
Organ systems assessed in Sequential Organ Failure Assessment (SOFA) scoring
6 (six)
Respiration
Coagulation
Liver
Cardiovascular
Central Nervous System
Renal
SOFA scoring diagnostic of SEPSIS
Increase of atleast 2 points in SOFA scoring from baseline, in the setting of suspected or documented infection
qSOFA parameters
RR >/= 22 bpm
Altered mental status
SBP = 100 mmHg
Most commonly used SOI scoring system in North America
THE APACHE II scoring system
What is shock?
Presence of multisystem end-organ hypoperfusion
Clinical indicators of Shock
Reduced MAP
Tachycardia
Tachypnea
Cool skin and extremities
Acute altered mental status
Oliguria
End result of multiorgan hypoperfusion
Tissue hypoxia, often accompanied by lactic acidosis
Mean Arterial Pressure
Cardiac Output x Systemic Vascular Resistance
Components of APACHE II scoring system
Rectal temperature
Mean blood pressure
Heart rate
Respiratory rate
Arterial pH
Oxygenation
Serum Sodium
Serum Potassium
Serum Creatinine
Hematocrit
WBC count
Glasgow Coma Score
Ag
Chronic Health Conditions
Clinical evidence of diminished cardiac output
Narrow Pulse Pressure
Cool extremities with delayed capillary refill
Signs of increased cardiac output
Widened pulse pressure ( ⬇️ diastolic pressure)
Warm extremities with bounding pulses
Rapid capillary refill
In hypotensive patients, with clinical signs of increased cardiac output, reduced BP is due to ___
Decreased Systemic vascular resistance
Better predictor of fluid responsiveness in hypotensive patients with reduced cardiac output
Change in right atrial pressure as a function of spontaneous respiration
Most common cause of High Cardiac Output Shock
Sepsis
Causes of Acute Hypoxemic Respiratory Failure
-Cardiogenic Shock
-Pulmonary Edema
-Septic shock with pneumonia
-ARDS
Causes of Ventilatory Failure
Increased load on the respiratory system
-Acute Metabolic (Lactic) Acidosis
Decreased Lung compliance
-Pulmonary Edema
Inadequate perfusion to respiratory muscles in the setting of shock
Predictor of fluid-responsiveness in spontaneously breathing patient
Inferior vena cava collapse seen on ultrasound
Signs of Respiratory Distress
-Inability to speak full sentences
-Accessory use of respiratory muscles
-Paradoxical abdominal muscle activity
-Extreme tachypnea (>40 bpm)
-Decreasing RR despite increasing drive to breathe
Goals in Mechanical Ventilation (2)
- Initially assume all or the majority of the work of breathing
- Facilitate a state of minimal respiratory muscle work
Decline in MAP seen during Mechanical Ventilation is caused by:
- Impeded venous return from positive-pressure ventilation
- Reduced endogenous catecholamine secretion once the stress associated with respiratory failure abates
- Actions of drugs used to facilitate endotracheal intubation
- Increase in RV afterload from positive-pressure ventilation in patients with Right Heart Dysfunction and Preexisting Pulmonary Hypertension
How to prevent decrease in MAP during intubation?
- IV volume administration
- Vasopressor support pre-intubation
This type of respiratory failure occurs with alveolar flooding and subsequent ventilation-perfusion mismatch and intrapulmonary shunt physiology
Type 1: Acute Hypoxemic Respiratory Failure
Categories of Pulmonary Edema
- Elevated Pulmonary Microvascular Pressures
A. Heart Failure
B. Intravascular Volume Overload - Low pressure Pulmonary Edema
A. Acute Respiratory Distress Syndrome
The pressure-volume relationship of the lung in ARDS in ______
Not linear
Principles in management of ARDS
- Low tidal volume 6mL/kg of IBW and High PEEP
- Prone positioning** improve survival
- Neuromuscular blockade
- Fluid-Conservative management strategy
This type of respiratory failure is a consequence of alveolar hypoventilation resulting from the inability to eliminate CO2 effectively
Type II: Hypercapneic Respiratory Failure
Mechanisms of Type II Respiratory Failure
- Impaired CNS drive to breathe
A. Drug Overdose
B. Brainstem Injury
C. Sleep-disordered breathing
D. Severe hypothyroidism - Impaired strength
A. Impaired neuromuscular transmission
-Myasthenia Gravis
-GBS
-Amyotrophic lateral sclerosis
B. Respiratory Muscle Weakness
-Myopathy
-Electrolyte derangements
-Fatigue - Increased load on the respiratory system
A. Resistive Loads
- Bronchospasms
B. Reduced Lung Compliance
- Alveolar edema
-Atelectasis
-Intrinsic PEEP (Auto-PEEP)
C. Reduced chest wall compliance
-Pneumothorax
-Pleural Effusion
-Abdominal Distention
D. Increased Minute Ventilation
-Pulmonary Embolism
-Increased dead-space fraction
-Sepsis
Treatment of Hypercapnic Respiratory Failure
Non-invasive positive-pressure ventilation with tight-fitting facial or nasal mask with avoidance of endotracheal intubation
This form of respiratory failure results from lung atelectasis
Type III: aka Perioperative Respiratory Failure
Pathophysiology of Lung atelectasis in Perioperative period
General anesthesia causes decrease in FRC –> Collapse of dependent lung units
Management of Type 3 Respiratory Failure
- Frequent changes in position
- Chest physiotherapy
- Upright positioning
- Control of incisional/abdominal pain
- Non-invasive Positive-pressure ventilation (Regional Atelectasis)
This form of respiratory failure results from hypoperfusion of respiratory muscles in patients with shock
Type IV Respiratory Failure
Management of Type IV Respiratory Failure
Intubation and Mechanical Ventilation
** This can allow redistribution of the cardiac output away from the respiratory muscles and back to vital organs while shock is being treated
Mainstay of therapy for analgesia in Mechanical Ventilation
Opiates
Indication for sedation in mechanically ventilated patients
- Adequate pain control
- Anxiolysis
- Treatment of subjective dyspnea
- Reduction of autonomic hyperactivity
Sedative associated with increased delirium and worse patient outcomes
Benzodiazepines
Neuromuscular blocking agent like CISATRACURIUM, occasionally used in patients with profound ventilator dyssynchrony despite optimal sedation, may result in prolonged weakness– a myopathy known as ___
Postparalytic syndrome
Neuromuscular blocking agent like CISATRACURIUM, occasionally used in patients with profound ventilator dyssynchrony despite optimal sedation, may result in prolonged weakness– a myopathy known as ___
Postparalytic syndrome
Amnesia can be best achieved by which drugs?
Propofol
Benzodiazepines (Lorazepam, Midazolam)
Parameters of Daily Screening of Respiratory Function
- If oxygenation is stable
-PFR >200
-PEEP = 5 - Cough and Airway reflexes are intact
- No vasopressor/sedatives
Spontaneous Breathing Trial
30-120 min of either:
1. CPAP 5 cm H20 with/out low level pressure support
2. Open T-piece system
Spontaneous Breathing Trial is declared a failure and stopped if any of the following occur:
- RR>35 bpm >5 min
- O2 sat <90%
- HR>140 bpm or a 20% increase or decrease from baseline
- SBP <90 mmHg or >180 mmHg
- Increased anxiety or diaphoresis
Percentage of patients who develop respiratory distress after extubation
10%
Simultaneous presence of physiologic dysfunction and/or failure of two or more organs
Multiorgan system failure
Gold standard for evaluation of respiratory gas exchange in critical illness
Arterial Blood Gas
Most commonly utilized non-invasive technique for monitoring respiratory function
Pulse oximetry
Variables to measure PEAK AIRWAY PRESSURE
- Airway Resistance
- Respiratory System Compliance
End respiratory pause
Plateau Pressure
Quantitative Measure of Airway Resistance
Peak Airway Pressure -Plateau Pressure
Normal: >10-15 mmHg
Definition of Respiratory System Compliance
The change in volume of the respiratory system per unit change in pressure
Normal respiratory system compliance
~100 mL/cm H20
Causes of decreased chest wall compliance
Pleural Effusion
Pneumothorax
Increased abdominal girth
Decreased lung compliance
Pneumonia
Pulmonary edema
Alveolar hemorrhage
Interstitial lung disease
Auto-PEEP
What is auto-PEEP?
Occurs when there is insufficient time for emptying of alveoli before the next inspiratory cycle
Common cause of Auto-PEEP
Obstructed DISTAL airways
1. Asthma
2. COPD
Leading cause of death in non-Coronary ICUs in the USA
Sepsis
Life threatening organ dysfunction caused by dysregulated response to infection
Sepsis
More effective for DVT prophylaxis in high risk patients, with lower incidence of heparin-induced thrombocytopenia
Low molecular weight heparin
e.g. Enoxaparin
Possible complications of PPI use
Increased risk of Pneumonia
Increased risk of Clostridium difficile colitis
Glucose goal in Critically ill patients
= 180 mg/dL
Complications of TPN
Hyperglycemia
Fatty liver
Cholestasis
Sepsis
ICU-acquired weakness most commonly occur ____
~ 1 week in the ICU
___ may reduce polyneuropathy in critical illness
Intensive Insulin Therapy
Causes of Anemia in the ICU
Chronic Inflammation
Phlebotomy
Most common underlying etiology of AKI in critically ill patients
Acute Tubular Necrosis
Definition of Delirium
- Acute onset of changes or fluctuations on mental status
- Inattention
- Disorganized thinking
- Altered level of consciousness
Sedative that has been less strongly associated with ICU delirium
Dexmedetomidine
Surgical procedure that relieves increased intracranial pressure in the setting of space-occupying lesions or brain swelling from stroke
Decompressive Craniectomy
Treatment for Cerebral Vasospasm in SAH
- CCB (Nimodipine)
- Aggressive IV fluid hydration
- Vasoactive drugs (Phenylephrine)
Hydrocephalus is typically heralded by _____.
Decreased level of consciousness
Most effective Benzodiazepine for treating status epilepticus
Lorazepam
Treatment of choice for controlling seizures acutely
Lorazepam
Diagnosis of Brain death requires:
- Absence of Cerebral Function
-No response to External Stimulus - No brainstem function
-Unreactive Pupils
-Lack of ocular movement in response to head turning or ice water irrigation of ear canals
-Positive apnea test
Reversible Causes of Coma
- Sedative effect
- Hypothermia
- Hypoxemia
- Neuromuscular paralysis
- Severe hypotension