0521779407-22 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:23
1522 Ventilator Management in the ICUTreatment for Specific Diseases
■Acute respiratory distress syndrome (ARDS) or acute lung injury
➣AC mode
➣Low tidal volume (6 ml/kg predicted body weight) reduces mor-
tality by 22% vs. traditional tidal volume (12 ml/kg)
➣If plateau pressure > 30 cm of water reduce tidal volume stepwise
by 1 ml per kg (minimum tidal volume 4 ml/kg)
➣Low tidal volume ventilation requires careful attention to seda-
tion and analgesia
➣Refer to full ARDS-network protocol available at http://hedwig.
mgh.harvard.edu/ardsnet
■Acute respiratory failure with chronic obstructive pulmonary disease
or asthma exacerbation
➣Bronchospasm increases risk of high airway pressure, baro-
trauma, and auto-PEEP
➣SIMV may be mode of choice; PCV is an alternative
➣AC mode increases risk of “breath stacking” due to inadequate
expiratory time, resulting in auto-PEEP (complications include
barotrauma and hypotension)
➣Set respiratory rate low (4–10), to allow adequate expiratory time
with target I:E ratio
>1:3
➣Set tidal volume 6–10 ml/kg
➣Target the patient’s “baseline” PaCO2, not a normal PaCO 2
➣If ventilation is difficult due to high airway pressures, allow “per-
missive” hypercapnea; consider bicarbonate infusion if pH < 7.15
➣Administer bronchodilators via endotracheal tube
■Other forms of acute respiratory failure
➣Most efficacious ventilator mode not established
➣AC is easiest, because patient can achieve “desired” minute ven-
tilationSide Effects & Complications
■General
➣Barotrauma – pneumothorax, pneumomediastinum, subcuta-
neous emphysema
➣Auto-PEEP (intrinsic PEEP or occult PEEP) – occurs when inad-
equate time for expiration; end-expiratory pressure rises; results
in hypotension or pneumothorax; test by performing end-
expiratory pause and measure airway pressure