Clinical Assessment of Control of Breathing

Milic–Emili, J.; Koutsoukou, Antonia; Stockley, Robert A.; Rennard, Stephen I.; Rabe, Klaus F.; Celli, Bartolomé R.

doi:10.1002/9780470755976.ch5

Cited by 4 publications

(7 citation statements)

References 55 publications

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“…At rest, the ventilatory pattern (Vt, Ti, Ttot, V' E , Vt/Ti) observed in our COPD and CVD patients was similar to that reported to that by other investigators [4,5,[12][13][14][15][19][20][21][22][23]. Bellemare and Grassino [1] showed that the critical product of Pdi/Pdimax and Ti/Ttot, tension-time index (TTdi) leading to diaphragmatic fatigue was 0.15 during inspiratory resistive loading at normal resting V' E .…”

Section: Control Of Ventilation and Its Relation To Bit In Copd And Csupporting

confidence: 77%

“…BIT was computed as (Ti/Ttot) × (Vt/FVC) [3], where Vt and Ti/Ttot were determined during steady states at the end of the preexercise and peak exercise periods, respectively. Coefficients of variation for tidal volume (Vt), inspiratory time (Ti), and expiratory time (V' E ) were 5%-15%, as reported for normal subjects and patients with COPD [12][13][14][15].…”

Section: Exercise Testing and Control Of Ventilationmentioning

confidence: 99%

“…Tidal volume (Vt), inspiratory time (Ti), and total time of the respiratory cycle (Ttot) were measured. From these values, the duty cycle (Ti/Ttot) and mean inspiratory flow (Vt/Ti) which corresponds to an intensity index of inspiratory activity (index of neural drive) were computed [12,13]. BIT was computed as (Ti/Ttot) × (Vt/FVC) [3], where Vt and Ti/Ttot were determined during steady states at the end of the preexercise and peak exercise periods, respectively.…”

Section: Exercise Testing and Control Of Ventilationmentioning

confidence: 99%

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Breathing Intolerance Index (BIT) and its Relation to Exercise Data: Noninvasive Assessment of Inspiratory Muscle Endurance during Rest and Exercise in Patients with Chronic Obstructive Pulmonary Disease and Cardiovascular Disorders

Baydur¹,

Tran²,

Pallickal³

et al. 2016

Chron Obstruct Pulmon Dis

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Rationale: Diaphragmatic tension-time index [TTdi = (Pdi/Pdimax)(Ti/ Ttot)] assesses inspiratory muscle endurance during rest and exercise. However, the procedure is invasive and not practical for general use. Recently, Tidal Volume/Vital Capacity (Vt/VC) has been substituted for Pdi/Pdimax, to assess need for assisted ventilation in chronic respiratory disorders. This technique has not been used to assess respiratory muscle endurance in other conditions during rest and exercise.Objective: To compare control of ventilation and BIT in cardiorespiratory disorders and controls and to assess their relation to oxygen uptake (V'O 2 ) and annual acute decompensations.Methods: BIT and V'O 2 were assessed in patients with stable CVD (n = 20), RD (n = 20) and C (n = 20) during bicycle ergometry. ANOVA assessed differences in variables amongst cohorts at rest and peak exercise. Results:Resting BIT was [median (25 th , 75 th percentiles)] 0.06 (0.04, 0.07), 0.06 (0.04, 0.09) and 0.04 (0.03, 0.05) for CVD, COPD and controls, respectively. Compared to resting, BIT increased by 3.0-to 4.6-fold at peak exercise in all cohorts (p < 0.0001). V'O 2 max exceeded resting values by 7.5-, 4.6-, and 9.4-fold in COPD, CVD and C, respectively (all p < 0.0001). When corrected for BIT (V'O 2 /BIT), controls exhibited significantly greater (V'O 2 /BIT) max than CVD and COPD (p < 0.0001). Amongst patients who acutely decompensated, BIT was higher only in resting CVD patients (p < 0.019). Conclusions:BIT is useful for evaluating respiratory muscle effort during rest and exercise in CVD and COPD. Oxygen uptake fails to increase in proportion to BIT in these conditions as much as in controls, reflecting impaired oxygen utilization. Its potential usefulness in predicting acute decompensations should be assessed in larger prospective studies.

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Section: Control Of Ventilation and Its Relation To Bit In Copd And Csupporting

confidence: 77%

Section: Exercise Testing and Control Of Ventilationmentioning

confidence: 99%

Section: Exercise Testing and Control Of Ventilationmentioning

confidence: 99%

See 1 more Smart Citation

Breathing Intolerance Index (BIT) and its Relation to Exercise Data: Noninvasive Assessment of Inspiratory Muscle Endurance during Rest and Exercise in Patients with Chronic Obstructive Pulmonary Disease and Cardiovascular Disorders

Baydur¹,

Tran²,

Pallickal³

et al. 2016

Chron Obstruct Pulmon Dis

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“…We think that the low total integrated Edi activation observed by Lourenço and Miranda in the hypercapnic patients is due, at least in part, to the shorter TI often exhibited by these patients [6,8,9,17,37]. With the present method, however, both an increase in peak (XP) activity and a shorter TI contributed to the progressive increase in Edi (XP/TI) from C to A (tables 2 and 4).…”

Section: Discussionmentioning

confidence: 48%

“…On the other hand, several lines of evidence indicate that a low mouth pressure response relative to Edi response may be considered as indicative of a low relationship between input and output signals of the system [19,21,28,37,41]. The observation that, irrespective of a normal ∆Edi/∆PCO 2 , ∆P0.1/∆PCO 2 was lower in group B patients than in either A or C groups seems consistent with the finding of a lower MIP in group B and to indicate a reduced inspiratory muscle ability to generate pressure in the face of a normal chemoresponsiveness.…”

Section: Discussionmentioning

confidence: 99%

Carbon dioxide responsiveness in COPD patients with and without chronic hypercapnia

Scano¹,

Spinelli²,

Duranti³

et al. 1995

Eur Respir J

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C Ca ar rb bo on n d di io ox xi id de e r re es sp po on ns si iv ve en ne es ss s i in n C CO OP PD D p pa at ti ie en nt ts s w wi it th h a an nd d w wi it th ho ou ut t c ch hr ro on ni ic c h hy yp pe er rc ca ap pn ni ia a G. Scano*, A. Spinelli*, R. Duranti*, M. Gorini**, F. Gigliotti**, P. Goti*, J. Milic-Emili † Carbon dioxide responsiveness in COPD patients with and without chronic hypercapnia. G. Scano, A. Spinelli, R. Duranti, M. Gorini, F. Gigliotti, P. Goti, J. Milic-Emili. ©ERS Journals Ltd 1995. ABSTRACT: To ascertain whether and to what extent the reduced ventilatory response to a hypercapnic stimulus in chronic obstructive pulmonary disease (COPD) patients depends on a blunted chemoresponsiveness of central origin or to mechanical impairment, we studied two groups of COPD patients without (group A) and with (group B) chronic hypercapnia, but with similar degrees of airway obstruction and hyperinflation.The study was performed on 17 patients (9 normocapnic and 8 hypercapnic). Six age-matched normal subjects (group C) were also studied as a control. During a CO 2 rebreathing test, ventilation (VE), mouth occlusion pressure (P0.1), and the electromyographic activity of diaphragm (Edi) were recorded and then plotted against end-tidal carbon dioxide tension (PCO 2 ).Inspiratory muscle strength was significantly lower in the hypercapnic group (group B) compared to normocapnic group (A), and in these groups compared to the control group (C). Both patient groups exhibited significantly lower ∆VE/∆PCO 2 than the control group. In hypercapnics, ∆P0.1/∆PCO 2 was significantly lower than in normocapnics and control group, whilst mouth occlusion pressure as % of maximal inspiratory pressure ∆P0.1(%MIP)/∆PCO 2 did not differ significantly among the three groups. ∆Edi/∆PCO 2 increased from C to A. At a PCO 2 of 8.65 kPa, VE was similar in the normocapnic and control group, but lower in hypercapnics; Edi was similar in hypercapnic and control group; but greater in normocapnics. P0.1(%MIP) did not differ significantly among groups.Although these data seem to suggest that CO 2 chemoresponsiveness was normal in hypercapnic and increased in normocapnic COPD patients, the lower VE at a PCO 2 of 8.65 kPa casts doubts about the adequacy of chemoresponsiveness in the hypercapnic group. In the latter, the reduced P0.1 response in face of normal P0.1(MIP) and Edi responses to carbon dioxide stimulation could suggest an impairment in inspiratory muscle function. Mechanical impairment and inadequate chemoresponsiveness are both likely to contribute to the low ventilatory response to CO 2 stimulation in chronic hypercapnic COPD patients. Eur Respir J., 1995, 8, 78-85

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Pathogenesis of respiratory failure in neuromuscular diseases: Diagnosis and treatment

Lissoni¹,

Molteni²

1986

Ital J Neuro Sci

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In reviewing the pathogenesis of respiratory failure in neuromuscular diseases, with special reference to ventilatory pump, we propose specific tests of the respiratory muscle pump alongside the standard function tests for assessing the respiratory system. Accurate diagnosis must be followed by target therapy, which must be given as often and for as long as needed. Early evaluation and treatment of the respiratory problems are essential to prognosis, whether of survival or of quality of life, in neuromuscular diseases.

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Clinical Assessment of Control of Breathing

Cited by 4 publications

References 55 publications

Breathing Intolerance Index (BIT) and its Relation to Exercise Data: Noninvasive Assessment of Inspiratory Muscle Endurance during Rest and Exercise in Patients with Chronic Obstructive Pulmonary Disease and Cardiovascular Disorders

Breathing Intolerance Index (BIT) and its Relation to Exercise Data: Noninvasive Assessment of Inspiratory Muscle Endurance during Rest and Exercise in Patients with Chronic Obstructive Pulmonary Disease and Cardiovascular Disorders

Carbon dioxide responsiveness in COPD patients with and without chronic hypercapnia

Pathogenesis of respiratory failure in neuromuscular diseases: Diagnosis and treatment

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