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Pressure and flow waveform characteristics of seven high-frequency ventilators
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Pressure and flow waveform characteristics of seven high-frequency ventilators Harcourt ER 1,2 , John J 3 , Dargaville PA 4 , Zannin E 5 , Davis PG 3,6 , Tingay DG 1,3,6 1 Royal Children’s Hospital, Parkville, Australia 2 Swinburne University of Technology, Hawthorn 3 Royal Women’s Hospital, Parkville 4 Royal Hobart Hospital, Hobart 5 Politecnico di Milano University, Milano, Italy 6 Murdoch Children’s Research Institute, Parkville, Australia CONCLUSION The HFV studied use different waveforms to generate pressure change within the lung. The clinical implications of the varying pressure and flow waveforms warrants investigation. HFV Wavefor m shape I:E Set ΔP P aomax (cm H 2 O) P aomin (cm H 2 O) V’ aomax (L/ min) V’ aomin (L/ min) FTN Rati o Sensormed ics (SM3100B) Square 1:2 1:1 30 cmH 2 O 21.2 1.9 18.1 -12.1 0.65* Drager VN500 Sinusoid al 1:2 30 cmH 2 O 13.4 0.3 17.3 -11.4 1.46 Drager Babylog (BL8000) Sinusoid al 1:2 30% of Max 13.0 4.8 8.2 -6.7 1.74 Fabian Sinusoid al 1:2 30 cmH 2 O 15.9 0.3 12.8 -10.4 1.39 Leoni+ Sinusoid al 1:2 30 cmH 2 O 14.7 0.8 12.8 -11.0 1.80 Sophie Sinusoid al 1:2 40% of Max 13.1 2.0 11.0 -6.9 1.33 SLE5000 Square 1:1 30 cmH 2 O 15.4 -7.8 15.2 -15.8 1.12 BACKGROUND • The pressure and flow waveform characteristics of older high-frequency ventilators (HFV) varies between machines. • Gas exchange in HFV is complex and waveform characteristics may contribute to effectiveness of ventilation. • The waveform characteristics of the newer HFV is unknown. METHODS Experimental Setup: • Infant test lung (560li, MI Instruments, Grand Rapids, MI) with 1.0 mL/cm H 2 O Compliance and 3.5mm diameter ETT. • Airway pressure measured (1000Hz) at the ETT hub (P ao ; SciReq, Montreal, Canada). • Flow (V’ ao ; Florian) measured (200Hz) at the airway opening. • Table 1 describes the HFV units tested and the Amplitude (DP). • In all units, a P aw of 10 cm H 2 O and Frequency 10 Hz was used. Data Analysis: • Recordings were made for 600 consecutive oscillatory cycles and the P ao and V’ ao waveform graphed (Figure 1). • Power spectral density analysis of the P ao OBJECTIVE To describe the pressure and flow waveform characteristics in seven commercially available HFV in a bench top study Table 1. Summary of waveform characteristics, maximum and minimum P ao and V’ ao and FTN ratio in seven HFV Figure 1. Representative P ao and V’ ao waveforms during two oscillatory cycles for each HFV tested. Unique incisurae patterns were noted within the waveforms of the SM3100B and SLE5000. ΔP set at 30 cm H 2 O or the % of maximum that resulted in 30 cm H 2 O at the proximal end of the ventilator circuit. * 1:2 ratio
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Pressure and flow waveform characteristics of seven high-frequency ventilators. Harcourt ER 1,2 , John J 3 , Dargaville PA 4 , Zannin E 5 , Davis PG 3,6 , Tingay DG 1,3,6 - PowerPoint PPT Presentation
Transcript of Pressure and flow waveform characteristics of seven high-frequency ventilators
Pressure and flow waveform characteristics of seven high-frequency ventilators
Harcourt ER1,2 , John J3, Dargaville PA4, Zannin E5, Davis PG3,6, Tingay DG1,3,6
1Royal Children’s Hospital, Parkville, Australia 2Swinburne University of Technology, Hawthorn 3Royal Women’s Hospital, Parkville 4Royal Hobart Hospital, Hobart 5Politecnico di Milano University, Milano, Italy 6Murdoch Children’s Research Institute, Parkville, Australia
CONCLUSIONThe HFV studied use different waveforms to generate pressure change within the lung. The clinical implications of the varying pressure and flow waveforms warrants investigation.
HFV Waveformshape I:E Set ΔP Paomax
(cm H2O)Paomin
(cm H2O)V’aomax
(L/min)V’aomin
(L/min)FTN
Ratio
Sensormedics (SM3100B) Square 1:2
1:1 30 cmH2O 21.2 1.9 18.1 -12.1 0.65*
Drager VN500 Sinusoidal 1:2 30 cmH2O 13.4 0.3 17.3 -11.4 1.46
Drager Babylog (BL8000)
Sinusoidal 1:2 30% of Max 13.0 4.8 8.2 -6.7 1.74
Fabian Sinusoidal 1:2 30 cmH2O 15.9 0.3 12.8 -10.4 1.39
Leoni+ Sinusoidal 1:2 30 cmH2O 14.7 0.8 12.8 -11.0 1.80
Sophie Sinusoidal 1:2 40% of Max 13.1 2.0 11.0 -6.9 1.33
SLE5000 Square 1:1 30 cmH2O 15.4 -7.8 15.2 -15.8 1.12
BACKGROUND• The pressure and flow waveform characteristics of older high-
frequency ventilators (HFV) varies between machines. • Gas exchange in HFV is complex and waveform characteristics
may contribute to effectiveness of ventilation.• The waveform characteristics of the newer HFV is unknown.
METHODSExperimental Setup:• Infant test lung (560li, MI Instruments, Grand Rapids, MI) with 1.0
mL/cm H2O Compliance and 3.5mm diameter ETT.• Airway pressure measured (1000Hz) at the ETT hub (Pao; SciReq,
Montreal, Canada). • Flow (V’ao; Florian) measured (200Hz) at the airway opening.• Table 1 describes the HFV units tested and the Amplitude (DP). • In all units, a Paw of 10 cm H2O and Frequency 10 Hz was used.
Data Analysis:• Recordings were made for 600 consecutive oscillatory cycles and
the Pao and V’ao waveform graphed (Figure 1).• Power spectral density analysis of the Pao waveform was
performed. • The ratio of fundamental signal (10 Hz) power to non fundamental
signal (total harmonics) power frequencies (FTN) was calculated to determine the waveform harmonic properties (Table 1).
• Lower FTN indicates a waveform with more frequency components.
OBJECTIVETo describe the pressure and flow waveform characteristics in seven commercially available HFV in a bench top study
Table 1. Summary of waveform characteristics, maximum and minimum Pao and V’ao and FTN ratio in seven HFV
Figure 1. Representative Pao and V’ao waveforms during two oscillatory cycles for each HFV tested. Unique incisurae patterns were noted within the waveforms of the SM3100B and SLE5000.
ΔP set at 30 cm H2O or the % of maximum that resulted in 30 cm H2O at the proximal end of the ventilator circuit. * 1:2 ratio
