Fig. 1

Graphical examples of type of breaths. Different graphical examples of type of breaths and its relationship with phase angle, breathing interval and coefficient of variation (CoV). CoV calculations are based upon multiple breathing cycles. Due to the schematic examples these cycles are not shown in the figure. Purple rectangle: ventilator pressurization, orange rectangle: patient effort, blue line: start of ventilator breath, red line: start of patient effort, gray arrow: patient breathing interval (TTOTNEU), green arrow: ventilator cycle (TTOTMECH), Φ: phase angle. A: Time triggered mandatory breath and no patient effort. Ventilator cycle (TTOTMECH) remains stable without variabilty. CoV calculations of the interval between mandatory breaths will be < 15%. Due to no patient efforts no phase angle calculations could be made. B: Spontaneous breathing pattern with changing timing in breathing interval (TTOTNEU) and different phase angles for each breath. Phase angles remain positive. CoV calculations for phase angle and breathing interval are showing no sign of respiratory entrainment and will be > 15%. C: Reverse triggering as a direct response to a time triggered breath. Both breathing interval (TTOTNEU) and phase angle are showing no variation. Phase angles will a be negative. CoV calculations of the breathing interval and phase angles are < 15%. D: Reverse triggering as part of respiratory entrainment. Patient triggered breaths and reverse triggering breaths are showing an alternating pattern. Phase angles will be positive, zero or negative. Breathing interval is showing little variabilty. CoV calculations for the breathing interval will be < 15% and for phase angle 10–15%. E: Double triggering during spontaneous breathing. Double triggering is patient triggered. CoV calculations of the breathing interval and phase angle are > 15%. F: Reverse triggering with double triggering during spontaneous breathing without respiratory entrainment. During double triggering the patient effort followed a time triggered mandatory breath. CoV calculations from both breathing interval and phase angle are > 15%. Hence, showing no relation with respiratory entrainment