The Latest in Critical Care, 12/4/23 (Issue #21)
Sighs: do they help? (SiVent trial); Delaying intubation in intoxicated patients (NICO trial).
Induced sighs in mechanically ventilated patients (SiVent trial)
In the 1960s, anesthesiologists noticed that if they gave a large breath (a “sigh”) to anesthetized patients every so often, their oxygenation improved. More seemed better, and soon all ventilated patients were getting lung-straining tidal volumes of 10-15 ml/kg. Those with persistent hypoxemia could be further topped off with recruitment maneuvers: delivering sustained PEEP of >50 cm H2O (60-70 cm H2O in obese patients) for 2 minutes or so was one published approach.
This all fell out of favor after low tidal volume ventilation’s reduced harms from volutrauma/barotrauma were repeatedly demonstrated. A European critical care society advised in 2023 against “sighs” resulting in pressure >35 cm H2O.
But not everyone gave up on sighs. Long-ago physiologic studies suggested sighs recruit surfactant, which is depleted even by low tidal volume ventilation. A few centers continued to study smaller, shorter, safer sighs in the con…
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