Acute Respiratory Distress Syndrome Flashcards
Annual incidence of ARDS pre-covid
60 cases/100,000 population
Clinical syndrome of severe dyspnea of rapid onset, hypoxemia, and diffuse pulmonary infiltrates leading to respiratory failure
Acute Respiratory Distress Syndrome
Most frequently reported surgical condition in ARDS (3)
- Pulmonary contusion
- Multiple bone fractures
- Chest wall trauma/flail chest
Most common cause of ARDS
Sepsis and Pneumonia (~40-60%)
Trauma patients with APACHE score of ____ have a 2.5-fold increased risk of developing ARDS
≥ 16
In this phase of ARDS, alveolar capillary endothelial cells and type 1 pneumocytes (alveolar epithelial cells) are injured, with consequent loss of the normally tight alveolar barrier
Exudative Phase (first 7 days of illness)
In this phase of ARDS, edema fluid that is rich in protein accumulates in the interstitial and alveolar spaces
Exudative phase
In this phase of ARDS, hyaline membrane whorls are seen.
Exudative Phase
Xray finding of ARDS
Opacities consistent with pulmonary edema, and often involves 3/4 of the lung field
Chest CT scan finding in ARDS
Presence of bilateral pulmonary infiltrates
Phase in ARDS where 1st signs of resolution is evident
Proliferative phase (days 7-21)
Phase of ARDS, recover rapidly and are liberated from mechanical ventilator
Proliferative phase (days 7-21)
Phase of ARDS, shift from neutrophil to lymphocyte-predominant pulmonary infiltrates
Proliferative phase (days 7-21)
As part of the reparative process in Proliferative phase, _____ proliferates along the alveolar basement membrane
Type II pneumocytes (synthesizes new surfactant)
In ARDS, presence of ____ in lung biopsy, in any phase of the disease, increases risk of mortality
Pulmonary Fibrosis
Function of PEEP
Promotes alveolar recruitment
This intervention provide significant reduction in 28-day mortality for patients with SEVERE ARDS
Prone positioning
Principle of Fluid Management in ARDS
Maintain low left atrial filling pressure
Fluid restriction and Diuretics limited only by hypotension and hypoperfusion
Only Category A recommendation in management for ARDS
Low tidal volume
Category D recommendation in management of ARDS (3)
Glucocorticoid treatment
Surfactant replacement
High frequency ventilation
Category B recommendation in management of ARDS (4)
HELP
Minimize left atrial filling pressure
High PEEP or Open Lung
Prone position
ECMO
Category C recommendation in management of ARDS (3)
RNV
Recruitment maneuvers
Early neuromuscular blockade (Routine Use)
Inhaled vasodilators
Goals and Limits in Management of ARDS
Tidal Volume ≤ 6 mL/kg
Plateau pressure ≤30 cmH2O
RR ≤35 bpm
FiO2 ≤ 0.6
SpO2 88-95%
pH ≥ 7.30
MAP ≥ 65 mmHg
Avoid Hypoperfursion
Patients with ARDS recover maximal lung function within ___
6 months
____ after endotracheal extubation, more than 1/3 of ARDS survivor have normal spirometry and normal diffusion capacity
1 year
Many patients with ARDS recover lung function ______ after initial pulmonary injury
3-4 weeks
Phase of ARDS, alveolar edema and inflammatory exudates of earlier phases convert to extensive alveolar duct and interstitial fibrosis
Fibrotic phase
Marked disruption of acinar architecture
leads to__________
emphysema-like changes, with large bullae.
Intimal fibroproliferation in the pulmonary microcirculation causes ______ (2)
- Progressive vascular occlusion
- Pulmonary hypertension
Physiologic consequences in Fibrotic Phase (3)
- Increased risk of pneumothorax
- Reductions in lung compliance
- Increased pulmonary dead space
General Principles in management of ARDS
- Recognition and treatment of underlying medical and surgical disorders (e.g., pneumonia, sepsis, aspiration, trauma)
- The minimization of unnecessary procedures and their complications
- Standardized “bundled care” approaches for ICU patients, including prophylaxis against venous thromboembolism, gastrointestinal bleeding, aspiration, excessive sedation, prolonged mechanical ventilation, and central venous catheter infections
- Prompt recognition of nosocomial infections
- Provision of adequate nutrition via the enteral route when feasible
Repeated alveolar overdistention from excess tidal volume
Volutrauma
Recurrent alveolar collapse
Atelectrauma
Trial about use of lung-protective strategy using lower tidal volumes of 6ml/kg of PBW
ARDS Network trial (ARMA Trial)
Maintaining a ____________ minimizes pulmonary edema and prevents further decrements in arterial oxygenation and lung compliance; improves pulmonary mechanics; and shortens ICU stay and the duration of mechanical ventilation.
Low left atrial filling pressure
Ways to lower left atrial filling pressure
Fluid restriction
Diuretics
limited only by hypotension and hypoperfusion of critical organs
Mortality rate for Mild ARDS
34.9%
Mortality rate for Moderate ARDS
40.3%
Mortality rate for Severe ARDS
46.1%
ARDS management that improves survival (3)
PEL
Low tidal volume
Prone prositioning
ECMO
Major risk factors to ARDS mortality is non-pulmonary. The most important risk factor is:
Advance age (>75)
TRUE OR FALSE
Patients with ARDS arising from direct lung injury are nearly twice as likely to die as those
with indirect causes of lung injury
TRUE
Factors associated with LESS recovery of pulmonary function after ARDS (4)
- Low static respiratory compliance
- High levels of required PEEP
- Longer duration of mechanical ventilation
- High lung injury scores
Early neuromuscular blockade with ___ for 48H in patients with severe ARDS had increased survival and ventilator free days without increasing ICU-acquired paresis
Cisatracurium besylate
Phase of ARDS: pulmonary vascular injury
Exudative Phase
Central feature of ARDS
Increased pulmonary vascular permeability leading to interstitial and alveolar edema fluid rich protein
