Faculty Opinions recommendation of Comparison of Arterial Oxygenation and Acid-Base Balance with the use of Transnasal Humidified Rapid-insufflation Ventilatory Exchange versus Tidal Volume Breathing with Continuous Positive Airway Pressure for Preoxygenation and Apneic Ventilation.

2018 ◽  
Author(s):  
Jay Brodsky
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Tidal Volume ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Arterial Oxygenation ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
Tidal Volume Breathing

FC 052ACID-BASE BALANCE DURING IN-SERIES EXTRACORPOREAL CARBON DIOXIDE REMOVAL AND CONTINUOUS VENOVENOUS HEMOFILTRATION: PREDICTIONS FROM A MATHEMATICAL MODEL

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
John (Ken) Leypoldt ◽  
Joerg Kurz ◽  
Jorge Echeverri ◽  
Markus Storr ◽  
Kai Harenski
Keyword(s):  
Carbon Dioxide ◽  
Mathematical Model ◽  
Tidal Volume ◽  
Carbon Dioxide Removal ◽  
Total Carbon ◽  
Acid Base Balance ◽  
Acid Base ◽  
Mechanically Ventilated ◽  
Base Balance ◽  
In Series

Abstract Background and Aims Critically ill acute kidney injury (AKI) patients may require treatment by extracorporeal carbon dioxide removal (ECCO2R) devices to allow protective or ultraprotective mechanical ventilation and avoid hypercapnic acidosis. Continuous venovenous hemofiltration (CVVH) and ECCO2R devices can be arranged in series to form a single extracorporeal circuit; such a circuit has been proposed to be optimal, based carbon dioxide removal efficacy, if the ECCO2R device is placed proximal to the CVVH device (Allardet-Servent et al, Crit Care Med 43:2570-2581, 2015). Method We developed a mathematical model of whole-body, acid-base balance during extracorporeal therapy using in-series ECCO2R and CVVH devices for treatment of mechanically ventilated AKI patients. Equilibrium acid-base chemistry in blood was assumed as reported previously (Rees and Andreassen, Crit Rev Biomed Eng 33:209-264, 2005). Published clinical data from Allardet-Servent et al of mechanically ventilated (6 mL/kg predicted body weight or PBW) AKI patients treated by CVVH without ECCO2R were used to adjust model parameters to fit plasma levels of arterial partial pressure of carbon dioxide (PaCO2) and arterial plasma bicarbonate concentration ([HCO3]). The effects of applying ECCO2R at an unchanged tidal volume and a reduced tidal volume (4 mL/kg PBW) on PaCO2 and [HCO3] were then simulated assuming carbon dioxide removal rates from the ECCO2R device measured in the clinical study (91 mL of CO2/min when ECCO2R was proximal and 72 mL of CO2/min when CVVH was proximal). Results Agreement of model predictions with the clinical data was good, and model predictions were relatively independent of the in-series position of the devices (see Table). Total carbon dioxide removal from the CVVH device via ultrafiltration predicted by the model was lower after applying ECCO2R at both the unchanged tidal volume (25 mL of CO2/min when ECCO2R was proximal and 39 mL of CO2/min when CVVH was proximal) and the reduced tidal volume (30 mL of CO2/min when ECCO2R was proximal and 44 mL of CO2/min when CVVH was proximal). The reduced removal of total carbon dioxide via ultrafiltration when ECCO2R was proximal resulted from the lower total carbon dioxide concentration in blood entering the CVVH device. Thus, independent of the in-series position of the devices, the magnitude of this difference in total carbon dioxide removal by the CVVH device (14 mL of CO2/min) approximately cancels out the relative greater efficacy of the ECCO2R device (19 mL of CO2/min). Conclusion The described mathematical model has quantitative accuracy. It suggests that overall acid-base balance when using ECCO2R and CVVH devices in a single, combined extracorporeal circuit will be similar, independent of their in-series position.

Inductance plethysmography measurement of CPAP-induced changes in end-expiratory lung volume

1990 ◽  
Vol 68 (4) ◽  
pp. 1732-1738 ◽  
Author(s):  
J. L. Werchowski ◽  
M. H. Sanders ◽  
J. P. Costantino ◽  
F. C. Sciurba ◽  
R. M. Rogers
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Tidal Volume ◽  
Lung Volume ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Normal Subjects ◽  
Residual Capacity ◽  
Highly Correlated ◽  
Induced Changes ◽  
Spontaneously Breathing

The respiratory inductance plethysmograph (RIP) has recently gained popularity in both the research and clinical arenas for measuring tidal volume (VT) and changes in functional residual capacity (delta FRC). It is important however, to define the likelihood that individual RIP measurements of VT and delta FRC would be acceptably accurate (+/- 10%) for clinical and investigational purposes in spontaneously breathing individuals on continuous positive airway pressure (CPAP). Additionally, RIP accuracy has not been compared in these regards after calibration by two commonly employed techniques, the least squares (LSQ) and the quantitative diagnostic calibration (QDC) methods. We compared RIP with pneumotachographic (PTH) measurements of delta FRC and VT during spontaneous mouth breathing on 0-10 cmH2O CPAP. Comparisons were made after RIP calibration with both the LSQ (6 subjects) and QDC (7 subjects) methods. Measurements of delta FRC by RIPLSQ and RIPQDC were highly correlated with PTH measurements (r = 0.94 +/- 0.04 and r = 0.98 +/- 0.01 (SE), respectively). However, only an average of 30% of RIPQDC determinations per subject and 31.4% of RIPLSQ determinations per subject were accurate to +/- 10% of PTH values. An average of 55.2% (QDC) and 68.8% (LSQ) of VT determinations per subject were accurate to +/- 10% of PTH values. We conclude that in normal subjects, over a large number of determinations, RIP values for delta FRC and VT at elevated end-expiratory lung volume correlate well with PTH values. However, regardless of whether QDC or LSQ calibration is used, only about one-third of individual RIP determinations of delta FRC and one-half of two-thirds of VT measurements will be sufficiently accurate for clinical and investigational use.

Respiratory correlates of muscle sympathetic nerve activity in heart failure

1998 ◽  
Vol 95 (3) ◽  
pp. 277-285 ◽  
Author(s):  
Matthew T. NAUGHTON ◽  
John S. FLORAS ◽  
M. Atiar RAHMAN ◽  
Munir JAMAL ◽  
T. Douglas BRADLEY
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Continuous Positive Airway Pressure ◽  
Tidal Volume ◽  
Spontaneous Breathing ◽  
Airway Pressure ◽  
Breathing Pattern ◽  
Positive Airway Pressure ◽  
Left Ventricular Ejection ◽  
Breathing Frequency

1.Sympathetic activation in congestive heart failure indicates a poor prognosis. Haemodynamic correlates of increased sympathetic nerve traffic to muscle (MSNA) and to the heart have been well characterized, but these account for only 50 to 60% of the variance in sympathetic activity between patients. 2.In healthy subjects, breathing pattern modulates MSNA and positive airway pressure consistently increases MSNA. However, in patients with heart failure, the influence of spontaneous breathing pattern and of short-term application of nasal continuous positive airway pressure on MSNA have not been described. 3.Spontaneous breathing frequency, tidal volume, end-expiratory lung volume, Pco2 and MSNA were recorded, along with blood pressure, heart rate and stroke volume in 14 men with congestive heart failure of idiopathic or ischaemic origin (left ventricular ejection fraction < 35%). Measurements were made during baseline rest, followed by 45 ;min of either nasal continuous positive airway pressure applied at 10 ;cmH2O (n = 9), or spontaneous breathing, in the absence of nasal continuous positive airway pressure (time control; n = 6). 4.At baseline, there was a significant positive correlation between MSNA burst frequency and breathing frequency (r = 0.758, P = 0.001), and an inverse correlation between MSNA burst incidence and tidal volume (r = -0.705, P = 0.005). These relationships were independent of left ventricular ejection fraction, stroke volume or cardiac output. 5.Nasal continuous positive airway pressure increased end-expiratory lung volume, but had no effect on breathing frequency, tidal volume or MSNA. 6.In patients with congestive heart failure, there is a significant independent and previously unrecognized correlation between spontaneous breathing pattern and MSNA; patients with rapid shallow breathing exhibit the highest degree of sympathetic activation. In distinct contrast to healthy subjects, the short-term application of nasal continuous positive airway pressure at 10 ;cmH2O does not increase MSNA in congestive heart failure.

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