On the Transition from Control Modes to Spontaneous Modes during ECMO

The transition from control modes to spontaneous modes is ubiquitous for mechanically ventilated patients yet there is little data describing the changes and patterns that occur to breathing during this transition for patients on ECMO. We identified high fidelity data among a diverse cohort of 419 mechanically ventilated patients on ECMO. We examined every ventilator change, describing the differences in >30,000 sets of original ventilator observations, focused around the time of transition from control modes to spontaneous modes. We performed multivariate regression with mixed effects, clustered by patient, to examine changes in ventilator characteristics within patients, including a subset among patients with low compliance (<30 milliliters (mL)/centimeters water (cmH2O)). We found that during the transition to spontaneous modes among patients with low compliance, patients exhibited greater tidal volumes (471 mL (364,585) vs. 425 mL (320,527); p < 0.0001), higher respiratory rate (23 breaths per minute (bpm) (18,28) vs. 18 bpm (14,23); p = 0.003), greater mechanical power (elastic component) (0.08 mL/(cmH2O × minute) (0.05,0.12) vs. 0.05 mL/(cmH2O × minute) (0.02,0.09); p < 0.0001) (range 0 to 1.4), and lower positive end expiratory pressure (PEEP) (6 cmH2O (5,8) vs. 10 cmH2O (8,11); p < 0.0001). For patients on control modes, the combination of increased tidal volume and increased respiratory rate was temporally associated with significantly low partial pressure of arterial oxygen (PaO2)/fraction of inspired oxygen (FiO2) ratio (p < 0.0001). These changes in ventilator parameters warrant prospective study, as they may be associated with worsened lung injury.

. Ventilator parameters by support mode Table S2. Subset analysis of ventilator parameters by support mode, among patients with lung compliance <30 cmH2O Table S3. Multivariate analysis of the association between spontaneous mode and tidal volume during the period of transition. (FOR FIGURE 2) Table S4. Multivariate analysis of the association between spontaneous mode and tidal volume during the period of transition, among patients with lung compliance <30 cmH20. Table S5. Multivariate analysis of the association between spontaneous mode and PEEP during the period of transition. (FOR FIGURE 1) Table S6. Multivariate analysis of the association between spontaneous mode and PEEP during the period of transition, among patients with lung compliance <30 cmH2O Table S7. Multivariate analysis of the association between spontaneous mode and elastic component of mechanical power during the period of transition. (FOR FIGURE 3) Table S8. Multivariate analysis of the association between spontaneous mode and elastic component of mechanical power during the period of transition, among patients with lung compliance <30 cmH2O. Table S9. Multivariate analysis of the association between duration of time since transition to spontaneous mode and respiratory rate during the period of transition. (FOR FIGURE S2) Table S10. Multivariate analysis of the association between duration of time since transition to spontaneous mode and respiratory rate during the period of transition, among patients with lung compliance <30 cmH2O. (FOR FIGURE 4) Table S11. Multivariate analysis of the association between duration of time since transition to spontaneous mode and PaO2/FiO2 during the period of transition, among patients with tachypnea. (FOR FIGURE 5) Table S12. Multivariate analysis of the association between duration of time since transition to spontaneous mode and PaO2/FiO2 during the period of transition, among patients without tachypnea. (FOR FIGURE S4) Table S13. Multivariate analysis of the association between duration of time since transition to spontaneous mode and PaO2/FiO2 during the period of transition, among patients with tachypnea, low compliance subset. (FOR FIGURE S3) Table S14. Multivariate analysis of the association between duration of time since transition to spontaneous mode and PaO2/FiO2 during the period of transition, among patients without tachypnea, low compliance subset. (FOR FIGURE S5) Table S15. Multivariate analysis of the association between respiratory rate and PaO2/FiO2 during the period of transition, among patients on control modes. (FOR FIGURE 6) Table S16. Multivariate analysis of the association between tidal volume and PaO2/FiO2 during the period of transition, among patients on control modes. (FOR FIGURE 6) Table S17. Multivariate analysis of the association between respiratory rate and PaO2/FiO2 during the period of transition, among patients on control modes, low compliance subset. (FOR FIGURE S6) Table S18. Multivariate analysis of the association between tidal volume and PaO2/FiO2 during the period of transition, among patients on control modes, low compliance subset. (FOR FIGURE S6) Figure S2. Adjusted increase in respiratory rate increases over time since the transition from control mode to spontaneous mode, among all patients                Tachypnea defined as respiratory rate ≥30.

Figures
Multivariate mixed effects panel regression model of one value per hour, clustered by patient. Tachypnea defined as respiratory rate ≥30.
Multivariate mixed effects panel regression model of one value per hour, clustered by patient. Tachypnea defined as respiratory rate ≥30.
Multivariate mixed effects panel regression model of one value per hour, clustered by patient. Tachypnea defined as respiratory rate ≥30.
Multivariate mixed effects panel regression model of one value per hour, clustered by patient.     Figure S1. Patient enrollment flowchart Figure S2. Adjusted increase in respiratory rate increases over time since the transition from control mode to spontaneous mode, among patients Figure S3. PaO2/FiO2 ratio (95% CI) over time among tachypneic patients (respiratory rate ≥30), low compliance subset. Figure S4. PaO2/FiO2 ratio (95% CI) over time among patients without tachypnea (respiratory rate <30). Figure S5. PaO2/FiO2 ratio (95% CI) over time among patients without tachypnea (respiratory rate <30), low compliance subset Figure S6. PaO2/FiO2 as a function of tidal volume and respiratory rate among patients with low compliance