Discordance Between Respiratory Drive and Sedation Depth in Critically Ill Patients Receiving Mechanical Ventilation
Amy L Dzierba1,2, Anas M Khalil3, Katrina L Derry4
1Center for Acute Respiratory Failure, Columbia University College of Physicians and Surgeons and New York-Presbyterian Hospital, New York, NY.
Objectives:
In mechanically ventilated patients, deep sedation is often assumed to induce "respirolysis," that is, lyse spontaneous respiratory effort, whereas light sedation is often assumed to preserve spontaneous effort. This study was conducted to determine validity of these common assumptions, evaluating the association of respiratory drive with sedation depth and ventilator-free days in acute respiratory failure.
Design:
Prospective cohort study.
Setting:
Patients were enrolled during 2 month-long periods in 2016-2017 from five ICUs representing medical, surgical, and cardiac specialties at a U.S. academic hospital.
Patients:
Eligible patients were critically ill adults receiving invasive ventilation initiated no more than 36 hours before enrollment. Patients with neuromuscular disease compromising respiratory function or expiratory flow limitation were excluded.
Interventions:
Respiratory drive was measured via P0.1, the change in airway pressure during a 0.1-second airway occlusion at initiation of patient inspiratory effort, every 12 ± 3 hours for 3 days. Sedation depth was evaluated via the Richmond Agitation-Sedation Scale. Analyses evaluated the association of P0.1 with Richmond Agitation-Sedation Scale (primary outcome) and ventilator-free days.
Measurements And Main Results:
Fifty-six patients undergoing 197 bedside evaluations across five ICUs were included. P0.1 ranged between 0 and 13.3 cm H2O (median [interquartile range], 0.1 cm H2O [0.0-1.3 cm H2O]). P0.1 was not significantly correlated with the Richmond Agitation-Sedation Scale (RSpearman, 0.02; 95% CI, -0.12 to 0.16; p = 0.80). Considering P0.1 terciles (range less than 0.2, 0.2-1.0, and greater than 1.0 cm H2O), patients in the middle tercile had significantly more ventilator-free days than the lowest tercile (incidence rate ratio, 0.78; 95% CI, 0.65-0.93; p < 0.01) or highest tercile (incidence rate ratio, 0.58; 95% CI, 0.48-0.70; p < 0.01).
Conclusions:
Sedation depth is not a reliable marker of respiratory drive during critical illness. Respiratory drive can be low, moderate, or high across the range of routinely targeted sedation depth.
More Related Videos
09:36Halogenated Agent Delivery in Porcine Model of Acute Respiratory Distress Syndrome via an Intensive Care Unit Type Device
Published on: September 24, 2020
07:52Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
Related Concept Videos
01:29Assessment of Ventilation II: Respiratory Depth and Rhythm
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
01:30Alterations in Respiration II
In Biot's breathing, the respiratory rate and depth are irregular, alternating between periods of deep gasping and apnea. Common causes...
01:23Acute Respiratory Failure-IV
01:30Acute Respiratory Failure-III
01:23Physiological Control of Respiration
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
01:24Factors Affecting Respiration