Hiccup-like Contractions in Mechanically Ventilated Patients: Individualized Treatment Guided by Transpulmonary Pressure

Figures

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  Figure 1. Flow, airway pressure (Paw), esophageal pressure (Pes), gastric pressure (Pgas), transpulmonary pressure (PL), and transdiaphragmatic pressure (Pdi) over time (s) during episodes of hiccups. PL was calculated by subtracting Pes from Paw. The patient is ventilated with pressure support ventilation with a level of support of 5 cmH2O and positive end-expiratory pressure of 6 cmH2O. During hiccup-like episodes, swings in Pes (blue arrow) and PL (purple arrow) were ΔPes = 22 cmH2O and ΔPL = 26 cmH2O, respectively, resulting in high flows and tidal volumes. Pdi swings were also very high (20 cmH2O), indicating intense diaphragmatic contractions. After the third ventilator breath, a burst of five inspiratory muscle contractions can be noticed, resulting in VT of 940 mL. Similar bursts of hiccup-like contractions were seen several times over the recording period.

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  Figure 2. Flow, airway pressure (Paw), esophageal pressure (Pes), and transpulmonary pressure (PL) over time (s) in a patient ventilated with volume controlled ventilation (VCV) with a VT of 500 mL (6 mL/kg PBW), positive end-expiratory pressure (PEEP) of 18 cmH2O, and respiratory rate of 27 breaths/min. PL was calculated by subtracting Pes from Paw (A). Before hiccup-like contractions (left panel of (A)), end-inspiratory and end-expiratory pauses (arrows) disclosed end-inspiratory (PLendinsp) and end-expiratory PL (PLendexp) of 8 and 4 cmH2O (purple arrows), respectively. Following the emergence of hiccup-like contractions emergence (right panel of (A)), hypoxemia led to PEEP increase at 20 cmH2O. Despite PEEP increase, PLendexp (purple arrows) was negative and hypoxemia worsened. When PEEP increased to 25 cmH2O, a positive PLendexp was sustained and hypoxemia improved (B). Despite high PEEP levels and high Paw plateau levels (34 cmH2O), PLendinsp calculated with the direct method (subtraction of Pes from Paw) was well below the upper safe threshold of 20 cmH2O and driving PL was also low (6 cmH2O). The elastance-derived calculation of PLendinsp disclosed a value of 22 cmH2O.

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  Figure 3. Flow, airway pressure (Paw), esophageal pressure (Pes), and transpulmonary pressure (PL) over time (s) during a burst of hiccup-like contractions. PL was calculated by subtracting Pes from Paw. The patient is ventilated with pressure support ventilation with a level of support of 5 cmH2O and positive end-expiratory pressure of 8 cmH2O. During normal breaths, the average ΔPes and ΔPL are 6 cmH2O and 9 cmH2O, respectively, and are associated with tidal volumes (VT) of ≈430 mL (6 mL/kg PBW). During hiccup-like episodes, large swings in Pes (blue arrow, ΔPes = 15 cmH2O) and PL (purple arrow, ΔPL = 19 cmH2O) can be noted. Bursts of hiccup-like contractions promoted multiple ventilator triggering. Multiple triggering was not associated with high VT (340 mL, 5 mL/kg PBW).