Introduction: Pressure support ventilation (PSV) should allow spontaneous breathing with a “normal” neuro-ventilatory drive. Low neuro-ventilatory drive puts the patient at risk of diaphragmatic atrophy while high neuro-ventilatory drive may causes dyspnea and patient self-inflicted lung injury. We continuously assessed for 12 hours the electrical activity of the diaphragm (EAdi), a close surrogate of neuro-ventilatory drive, during PSV. Our aim was to document the EAdi trend and the occurrence of periods of “Low” and/or “High” neuro-ventilatory drive during clinical application of PSV.
Method: In 16 critically ill patients ventilated in the PSV mode for clinical reasons, inspiratory peak EAdi peak (EAdiPEAK), pressure time product of the trans-diaphragmatic pressure per breath and per minute (PTPDI/b and PTPDI/min, respectively), breathing pattern and major asynchronies were continuously monitored for 12 hours (from 8 a.m. to 8 p.m.). We identified breaths with “Normal” (EAdiPEAK 5 - 15 mV), “Low” (EAdiPEAK < 5 mV) and “High” (EAdiPEAK >15 mV) neuro-ventilatory drive.
Results: Within all the analyzed breaths (177.117), the neuro-ventilatory drive, as expressed by the EAdiPEAK, was “Low” in 50.116 breath (28 %), “Normal” in 88.419 breaths (50 %) and “High” in 38.582 breaths (22 %). The average times spent in “Low”, “Normal” and “High” class were 1.37, 3.67 and 0,55 hours, respectively (p < 0.0001), with wide variations among patients. Eleven patients remained in the “Low” neuro-ventilatory drive class for more than one hour, median 6.1 [3.9 - 8.5] hours and 6 in the “High” neuro-ventilatory drive class, median 3.4 [2.2 – 7.8] hours. The asynchrony index was significantly higher in the “Low” neuro-ventilatory class, mainly because of a higher number of missed efforts.
Conclusions: We observed wide variations in EAdi amplitude and unevenly distributed “Low” and “High” neuro ventilatory drive periods during 12 hours of PSV in critically ill patients. Further studies are needed to assess the possible clinical implications of our physiological findings.
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Posted 14 Sep, 2020
On 21 Oct, 2020
On 08 Oct, 2020
Received 16 Sep, 2020
Invitations sent on 15 Sep, 2020
On 15 Sep, 2020
On 11 Sep, 2020
On 10 Sep, 2020
On 10 Sep, 2020
On 12 Aug, 2020
Received 11 Aug, 2020
Received 09 Aug, 2020
On 04 Aug, 2020
On 22 Jul, 2020
Invitations sent on 21 Jul, 2020
On 20 Jul, 2020
On 19 Jul, 2020
On 19 Jul, 2020
On 13 Jul, 2020
Posted 14 Sep, 2020
On 21 Oct, 2020
On 08 Oct, 2020
Received 16 Sep, 2020
Invitations sent on 15 Sep, 2020
On 15 Sep, 2020
On 11 Sep, 2020
On 10 Sep, 2020
On 10 Sep, 2020
On 12 Aug, 2020
Received 11 Aug, 2020
Received 09 Aug, 2020
On 04 Aug, 2020
On 22 Jul, 2020
Invitations sent on 21 Jul, 2020
On 20 Jul, 2020
On 19 Jul, 2020
On 19 Jul, 2020
On 13 Jul, 2020
Introduction: Pressure support ventilation (PSV) should allow spontaneous breathing with a “normal” neuro-ventilatory drive. Low neuro-ventilatory drive puts the patient at risk of diaphragmatic atrophy while high neuro-ventilatory drive may causes dyspnea and patient self-inflicted lung injury. We continuously assessed for 12 hours the electrical activity of the diaphragm (EAdi), a close surrogate of neuro-ventilatory drive, during PSV. Our aim was to document the EAdi trend and the occurrence of periods of “Low” and/or “High” neuro-ventilatory drive during clinical application of PSV.
Method: In 16 critically ill patients ventilated in the PSV mode for clinical reasons, inspiratory peak EAdi peak (EAdiPEAK), pressure time product of the trans-diaphragmatic pressure per breath and per minute (PTPDI/b and PTPDI/min, respectively), breathing pattern and major asynchronies were continuously monitored for 12 hours (from 8 a.m. to 8 p.m.). We identified breaths with “Normal” (EAdiPEAK 5 - 15 mV), “Low” (EAdiPEAK < 5 mV) and “High” (EAdiPEAK >15 mV) neuro-ventilatory drive.
Results: Within all the analyzed breaths (177.117), the neuro-ventilatory drive, as expressed by the EAdiPEAK, was “Low” in 50.116 breath (28 %), “Normal” in 88.419 breaths (50 %) and “High” in 38.582 breaths (22 %). The average times spent in “Low”, “Normal” and “High” class were 1.37, 3.67 and 0,55 hours, respectively (p < 0.0001), with wide variations among patients. Eleven patients remained in the “Low” neuro-ventilatory drive class for more than one hour, median 6.1 [3.9 - 8.5] hours and 6 in the “High” neuro-ventilatory drive class, median 3.4 [2.2 – 7.8] hours. The asynchrony index was significantly higher in the “Low” neuro-ventilatory class, mainly because of a higher number of missed efforts.
Conclusions: We observed wide variations in EAdi amplitude and unevenly distributed “Low” and “High” neuro ventilatory drive periods during 12 hours of PSV in critically ill patients. Further studies are needed to assess the possible clinical implications of our physiological findings.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
This is a list of supplementary files associated with this preprint. Click to download.
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