Critical Management Principles Flashcards
3 criteria for decision to intubate
- Failure to maintain or protect airway - pt’s ability to swallow/handle secretions
- Failure of ventilation/oxygenation - clinical status, oxygen saturation, ventilatory pattern
- Anticipated clinical course and likelihood of deterioration - moderate/high likelihood of predictable airway deterioration or need for intubation to facilitate pt’s evaluation and treatment
LEMON mnemonic for evaluation of difficult direct laryngoscopy
L - Look externally for signs of difficult intubation
E-Evaluate 3-3-2 rule
M-Mallampati scale
O-Obstruction/Obesity
N-Neck mobility
Cormack and Lehane grading system for glottic view (1-4) during direct laryngoscopy
1 and 2: Vocal cords visualized; high chance of success
3 and 4: Cannot visualize glottic aperture, success less likely
Mallampati scale (class I-IV)
I: visualize soft palate, uvula, fauces, pillars
II: soft palate uvula, fauces
III: soft palate, base of uvula
IV: only hard palate
7 P’s of rapid sequence intubation
Preparation Preoxygenation Pretreatment Paralysis + induction Positioning Placement of tube Postintubation management
Indications for necessity for pretreatment agents for rapid sequence intubation
- Reactive airway disease – Albuterol 2.5mg by nebulizer. If time doesn’t permit albuterol, give lidocaine 1.5mg/kg IV
- CV disease – Fetanyl 3 µg/kg to mitigate sympathetic discharge
- Elevated ICP – Fentanyl 3µg/kg to mitigate sympathetic discharge and attendant rise in ICP
** give 2-3 min before induction and paralysis
Appropriate amount of preoxygenation in RSI
Administration of 100% oxygen for 3 minutes of normal tidal volume breathing in normal healthy adult → adequate oxygen reservoir to permit 6-8min of safe apnea before desat to >90%
If time is insufficient, 8 vital capacity breaths with high-flow oxygen can achieve saturations and apnea times that match traditional preoygenation.
Depolarizing neuromuscular blocking agent used for RSI:
Dose?
Time to onset?
Duration?
Side effects?
Succinylcholine 1.5mg/kg
Onset: <45s
Duration: 6-10min
Side effects: Bradycardia (?atropine in peds), hyperkalemia in pts with up-regulation of ACh-receptors, fasiculations/muscle pain masseter spasm, malignant hyperthermia
Conditions associated with hyperkalemia after succinylcholine administration
Burns >10% BSA, >5 days since injury until healed
Crush injury, >5 days since injury until healed
Denervation (stroke, spinal cord injury), >5 days since event until 6mo post injury
Intraabdominal sepsis, >5 days since onset until resolution
NM disease (ALS, MS, MD), onset and indefinitely
Competitive/Non-depolarizing neuromuscular blocking agent used for RSI
Dose?
Onset?
Duration?
Side effects?
Rocuronium 1-1.2 mg/kg
Onset: 60s
Duration: 50min
No real side effects or contraindications.
Long duration of action may not be desirable in pts requiring frequent neuro checks.
Induction agent options for RSI
Etomidate
Ketamine
Propofol
Etomidate
Dose?
Benefits?
Side effects?
Etomidate 0.3mg/kg IV
No adverse hemodynamic effects
Decreases ICP, cerebral blood flow without adversely affecting systemic MAP and cerebral perfusion pressure
May ↓ serum coritsol levels transiently and blunt adrenal response to ACTH (?worse survival with sepsis)
Ketamine
Dose? Onset? Duration? Benefits? Side effects?
Ketamine 1-2mg/kg
Onset: 30s-1min
Duration: 10-15min
Protective airway reflexes and ventilatory drive usually preserved
Good with acute severe asthma.
Less propensity to exacerbate hemodynamic instability
May ↑ cerebral metabolic rate, ICP, CBF
May ↑ BP and catecholamine release - avoid in TBI and HTN
Emergency phenomena
Propofol
Induction dose?
Benefits?
Side effects?
Propofol 1.5mg/kg IV, reduced in older pts or those with hemodynamic compromise or poor cardiovascular reserve
Can cause hypotension through vasodilation and direct myocardial depression
Delivered in soybean oil and lecithin vehicle - avoid with anaphylaxis to egg proteins
Pain at site of administration - use proximal vein and/or pretreat with lidocaine/opioids/ketamine
Midazolam
Induction dose?
Onset?
Duration?
Cautions?
Midazolam 0.2-0.3mg/kg IV
Onset: 30-120s
Duration 15-20min
Negative inotrope; use with caution in hemodynamically compromised and older patients
Precedex (Dexmedetomidine)
Loading dose?
Benefits?
Limitations?
Precedex (Dexmedetomidine)
Loading dose 1mg/kg IV over 5-10min
Minimal effect on respiratory drive or protective airway reflexes
Limited by bradycardia and hypotension
Specific RSI for status asthmaticus
Preoxygenation - ↓ TV and RR to prevent breath stacking
Pretreatment - albuterol 2.5mg nebulized, or Lidocaine 1.5mg/kg IV
Paralysis - Succinylcholine 1.5mg/kg IV
Induction - Ketamine 1.5mg/kg (bronchodilation)
Specific RSI for elevated ICP
Pretreatment - fentanyl 3µg/kg (slowly)
Paralysis - Succinylcholine 1.5mg/kg IV
Induction - Etomidate 0.3mg/kg
Postintubation - Propofol to permit frequent neuro exams
Specific RSI for hypotension and shock
Preparation - Isotonic fluid boluses/blood products
Pretreatment - Phenylephrine HCl (Neosynephrine) 50-100µg IVP (if still hypotensive after IV fluids)
Paralysis - Succinylcholine 1.5mg/kg IV
Induction - Ketamine 0.5-0.75mg/kg OR Etomidate 0.1-0.15mg/kg IV
Cardiovascular effects of positive pressure ventilation (PPV)
PPV → diminished venous return → ↓ cardiac output → ↓ pressure gradient between LV and aorta → hypotension
** may be exaggerated in pts with clinical hypovolemia or vasodilatory states
Pressure controlled ventilation (PCV)
Set parameters?
Variable parameters?
Clinical implications?
Clinical conditions?
Set: Pressure target, inspiratory time, RR, PEEP
Variable: Tidal volume, inspiratory flow rate
Implications: controls airway pressure, but TV becomes function of compliance. Allows estimation of end-inspiratory alveolar pressure based on vent settings. Variable inspiratory flow helpful for pts with high respiratory drive.
Conditions: severe asthma, COPD, salicylate toxicity
Volume controlled ventilation (VCV).
Set parameters?
Variable parameters?
Implications?
Conditions?
Set: tidal volume, RR, inspiratory flow pattern, inspiratory flow time
Variable: PIP, end-inspiratory alveolar pressure
Implications: guaranteed delivery of tidal volume, but may result in high/injurious lung pressures. End-inspiratory alveolar pressure can’t be reliably estimated and must be measured (plateau pressure)
Conditions: ARDS, obesity, severe burns
Ventilator mode: Assist-control (A/C) aka continuous mechanical ventilation (CMV)
Parameters set by provider?
Clinical scenario?
Assist-control (A/C) aka continuous mechanical ventilation (CMV)
Parameters set by provider: Pressure or volume control, RR
Clinical scenario: paralyzed/deeply sedated, sedated pts with intermittent spontaneous respiratory effort; can lead to hyperventilation
Ventilator mode: Synchronized intermittent mandatory ventilation (SIMV)
Parameters set by provider?
Clinical scenario?
Synchronized intermittent mandatory ventilation (SIMV)
Parameters: Pressure or volume control, RR (backup rate)
Scenario: pts with regular but poor spontaneous respiratory effort; if used in deeply sedated pts, set RR will need to be higher
Ventilator mode: Pressure-support ventilation (PSV)
Parameters set by provider?
Clinical scenario?
Pressure-support ventilation (PSV)
Parameters: Level of pressure support, PEEP
Scenario: Spontaneously breathing pts with good respiratory effort requiring minimal ventilatory support
Purpose of PEEP
Adverse effects?
PEEP - positive end-expiratory pressure
Maintains positive airway pressure after completion of passive expiration → ↑ functional residual capacity (FRC) → ↑ oxygenation → ↓ intrapulmonary shnting
Also reduces portions of nonaerated lung that may contribute to development of VILI
PEEP increases intrapulmonary and intrathoracic pressures
Adverse effects: ↓CO, lung overdistention, pneumothorax
Relative contraindications to NPPV
Decreased level of consciousness Lack of respiratory drive Increased secretions Hemodynamic instability Facial trauma
Initial IPAP and EPAP settings
IPAP 10cm H2O
EPAP 5cm H2O
Effects of increasing IPAP
↑ IPAP → ↓ Hypercarbia
by ↑ tidal volume and minute ventilation
Effects of increasing EPAP
↑ EPAP → ↑ Oxygenation
by ↑ alveolar recruitment and ↓ atelectasis
Initial vent settings for an intubated pt in the ED:
TV
RR
FiO2
PEEP
TV 6-8mL/kg of ideal body weight
(if PCV, adjust target pressures to get ideal TV)
RR 12-14/min
Initial pressure targets should not exceed 30cm H2O
FiO2 should be set at 1.0 saturation of 90% or greater
PEEP 5cm H2O
Causes of respiratory distress on ventilator:
Acutely unstable
Improves with removal from ventilator
Likely iPEEP - resume mechanical ventilation with ↓ RR and ↑ expiratory time
Causes of respiratory distress on ventilator:
Acutely unstable
Does not improve with removal from ventilator
Presumptive treatment for tension pneumothorax with needle decompression.
If pt remains unstable, other diagnoses should be pursued, including PE
Causes of respiratory distress on ventilator: Not acutely unstable ETT in proper place PIP elevated Plateau pressure normal
↑ PIP with normal Pplat = increased airway or circuit resistance
Worsening airway obstruction from underlying pathology New bronchospasm (e.g. allergic reaction) ETT obstruction Ventilator circuit obstructed
Causes of respiratory distress on ventilator Not acutely unstable ETT in proper place PIP elevated Plateau pressure elevated
↑ PIP with ↑ Pplat = decreased respiratory system compliance
Worsening lung compliance from underlying pathology Pneumothorax Abdominal distension Inadequate sedation Ventilatory dyssynchrony
Vent settings for acute COPD exacerbation
Focus: improve gas exchange while minimizing iPEEP
↓ airway resistance with bronchodilators and corticosteroids
Ensure adequate expiratory time by ↓RR, ↓ TV, and ↓inspiratory time
Reduce minute ventilation (permissive hypercapnia)
Inspiratory:expiratory (I/E ratio) should initially set at 1:4
PEEP set at 5cm H2O
Avoid NBMAs + corticosteroids, increased risk for polymyopathy of critical illness and subsequent increased mortality