By Stacey Butterfield
Primum non nocere is a founding principle of medicine generally, but it especially applies to mechanical ventilation, according to Sushma Cribbs, MD, MSc, an associate professor in the department of pulmonary, allergy, sleep, and critical care at Emory University School of Medicine in Atlanta.
“It's important to remember that there are several goals of mechanical ventilation,” she said. “Of course we want to preserve life and improve gas exchange, and we want to remember to do no harm, which means we want to minimize time on the ventilator.”
Dr. Cribbs offers a host of tips on ventilator management and troubleshooting during her Internal Medicine Meeting 2021: Virtual Experience session, available on Friday at 11:45 a.m.
One common harm is ventilator-induced lung injury, most often seen in patients with acute respiratory distress syndrome (ARDS). “But over the past few years, it has become clear that it also occurs in patients ventilated for other reasons as well,” said Dr. Cribbs. There are a number of potential mechanisms of ventilator-induced lung injury: volutrauma, atelectrauma, biotrauma, and barotrauma.
There is one very effective solution, though, when it comes to ventilating patients with ARDS. “The best mechanism is to employ a strategy of low-tidal-volume ventilation, a proven therapy in ARDS known to reduce mortality,” she said, citing a landmark trial published in the New England Journal of Medicine in 2000.
Although that study was conducted by the ARDS Network, the benefits of low-tidal volume also apply to other patients at risk for acute lung injury, such as those who have sepsis or are being put under anesthesia. This ventilation strategy has also been shown to reduce pulmonary complications, she noted.
“Low-tidal-volume ventilation is not just for ARDS and should be considered in all mechanically ventilated patients," said Dr. Cribbs. “Low-tidal-volume ventilation is the standard of care in the ICU nowadays.”
Another key to ventilating patients without causing lung injury is targeting the correct plateau pressure, which is 30 cm H2o or less for patients with ARDS. For more specifics on optimizing ventilation, she points internists to a ventilation protocol available online from the ARDS Network.
Those who listen to her talk can get additional details, as well as learn about some other hot topics in ventilation, including prone positioning and racial disparities.
“If you are going to prone, please be aware of contraindications,” which include spinal instability, anterior burns, pregnancy, and increased intracranial pressure, said Dr. Cribbs. "Also remember that early is better. Prone positioning has the optimal benefit when implemented early, ideally 36 hours after intubation, and at a high dose, which we consider 12 to 18 hours per day.”
On the subject of disparities, she mentions that White patients have lower risk of developing ARDS and of dying from it than patients of other racial/ethnic groups. Researchers haven't yet figured out why that is. "Regardless, health care disparities are a very important area of study, and it's critical that we keep this in mind as health care providers," Dr. Cribbs said. ■