Ventilator Management for ICU Patients

General Principles

The American Thoracic Society recommends using lower tidal volumes (4-8 ml/kg predicted body weight) and lower inspiratory pressures (plateau pressure ≤30 cmH2O) for all patients with ARDS to reduce mortality 1, 2
Target oxygen saturation of 88-92% for most patients to avoid oxygen toxicity while maintaining adequate oxygenation 4

The American College of Chest Physicians recommends using low tidal volume ventilation (4-8 ml/kg predicted body weight) with plateau pressure <30 cmH2O for ARDS patients 1, 2, 3
For moderate to severe ARDS, use higher PEEP (typically 10-15 cmH2O) 1, 3
Consider recruitment maneuvers in patients with moderate or severe ARDS 3
For severe ARDS, implement prone positioning for more than 12 hours per day 1, 2
Avoid routine use of high-frequency oscillatory ventilation 1, 2
Consider extracorporeal membrane oxygenation (ECMO) for severe refractory ARDS 1

The British Thoracic Society recommends non-invasive ventilation (NIV) as the first-line ventilatory support for COPD exacerbations with respiratory acidosis 4, 5
For NIV, use bi-level pressure support with initial IPAP of 10-15 cmH2O and EPAP of 4-8 cmH2O 4
Maintain a pressure difference between IPAP and EPAP of at least 5 cmH2O 4
Set backup respiratory rate of 10-14 breaths/min 4
If invasive ventilation becomes necessary, use assist-control mode initially with tidal volumes of 6-8 ml/kg 4
Set PEEP between 4-8 cmH2O to offset intrinsic PEEP and improve triggering 4
Allow adequate expiratory time (I:E ratio of approximately 1:2 or 1:3) to prevent air trapping 4

The British Thoracic Society recommends using NIV cautiously in asthma and only in an HDU or ICU where immediate intubation is available 6
Monitor for auto-PEEP and adjust ventilator settings to minimize it 7

CPAP is primarily used to correct hypoxemia by recruiting underventilated lung areas 7
It increases mean airway pressure similar to PEEP in intubated patients 7
CPAP unloads inspiratory muscles and reduces work of breathing 7
In COPD, CPAP can offset intrinsic PEEP, reducing ventilatory work and potentially decreasing PaCO2 7
Flow generators need to maintain desired pressure throughout the respiratory cycle 7

Combines pressure support (IPAP) for ventilation with CPAP (EPAP) for lung recruitment 7
IPAP provides inspiratory assistance while EPAP recruits underventilated lung and offsets intrinsic PEEP 7
EPAP also serves to vent exhaled gas through the exhaust port 7
Most effective mode of NIV for COPD patients 4

Recheck arterial blood gases after 30-60 minutes of ventilation or if clinical deterioration occurs 4
For NIV failure, check for technical issues and optimize ventilator settings before considering intubation 5
Consider intubation if there is persistent or deteriorating acidosis despite optimized NIV 5

Excessive oxygen therapy leading to worsening hypercapnia in COPD patients - maintain target saturation of 88-92% 4
Inadequate expiratory time causing dynamic hyperinflation and auto-PEEP, especially in obstructive lung diseases 4
Insufficient PEEP leading to atelectasis and worsening V/Q mismatch 4
Delayed escalation to invasive ventilation when NIV is failing - monitor closely for worsening ABGs 4, 5

Essential features include pressure control capability of at least 30 cmH2O, support for inspiratory flows of at least 60 L/min, assist-control and bi-level pressure support modes, and disconnection alarms 8
Desirable features include adjustable pressure rise time, inspiratory and expiratory triggers, and internal battery backup 8
For acute respiratory failure, ventilators with inspiratory pressure as the controlled variable (bi-level devices) are preferred 8