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Influence of Noninvasive Positive Pressure Ventilation on Inspiratory Muscles: Results (1)

Influence of Noninvasive Positive Pressure Ventilation on Inspiratory Muscles: Results (1)Each of the subjects had respiratory failure (mean±SD: PaC02, 60 ±13 mm Hg; Pa02, 43 ±11 mm Hg; Sa02 75 ± 12 percent) consequent on restrictive ventilatory disease with a reduced vital capacity (VC) and total lung capacity and flow rates appropriate to the observed lung volumes (Table 1). Maximum inspiratory pressures at residual volume and functional residual capacity were reduced as was maximum expiratory pressure and maximum voluntary ventilation (Table 2). Although subjects received supplemental oxygen during the initial sleep study, saturation levels fell substantially, especially during REM sleep •(Table 3). Buy Advair Diskus Online

Similarly, the highest values of Pco2 were found during REM sleep (mean high REM = 106±31 mm Hg, Table 4). Subjects consistently displayed a rapid shallow pattern of breathing with a further reduction, especially in rib cage excursion during REM sleep (Fig 1a). During assisted ventilation, subjects were able to breathe room air while maintaining saturation throughout each of the sleep stages at a relatively low ventilator pressure (20 to 25 cm HaO) Fig 2). After 12 weeks of nocturnal ventilation, nocturnal Pco2 and Sa02 without ventilatory support were noted to have improved as compared with the initial measurements.

Table 1—Individual Pulmonary Function Measurements at Baseline and Means (± Standard Deviation) at Baseline, Three Months and 14 Months After Ventilation

Subject Dx Sex Age,yr Height,cm Wfeight,kg VC,%pred FEVj,%pred FEV./FVC,% V50,%pred V25,%pred TLC,%pred
1 ITR M 29 143 56 27 25 85.7 34 27 36
2 ITR F 35 132 30 21 20 75.0 21 11 44
3 NMD F 21 174 51 28 38 100.0 90 109 40
4 ITR F 57 146 46 33 31 70.0 23 13 47
5 PPTR F 39 153 52 15 12 75.0 9 6 35
6 ITR F 66 155 81 40 44 88.9 43 8 36
Baseline 36± 13 150 ±16 47 ±10 25±7 25 ±10 81.1 ±12.0 35 ±32 33 ±43 40±5
3 mo 28±5 27 ±9 82.8±11.5 32 ±29 34±42 44±6t
14 mo 30±7 29 ±15 74.2 ±15.8 30 ±26 29 ±39 46±5t

Table 2—Strength and Endurance at Baseline, Three Months, and 14 Months After Nocturnal Ventilation

miprv,—cm H20 MIP^c, —cm H20 MEP, cm HsO MvyL/min Pm,%MIPhv Tum,min
Baseline 42± 10 30±7 81 ±28 29 ±22 44± 13 7.1±3.4
3 mo 51 ±17 32 ±7 92± 18 34 ±20 38± 10 14.8±7.6f
14 mo 47 ±14 28 ±10 84 ±42 39 ±32 49 ±5 17.2 ±6.3

Table 3—Oxygen Saturation During Sleep at Baseline Unassisted, During Ventilation, and on the First Postventilatory Night Following 12 Weeks of Nocturnal Ventilation

ID Awake Stage 1 and 2 SWS REMS
High Low High Low High Low High Low
Baseline (oxygen)
1 94 94 94.5 94.0 93 93 89 77
2 93 89 92.0 68.0 94 69 92 68
3 94 94 93.0 92.0 91 90 79 70
4 92 46 86.5 57.0 84 65 79 44
5 95 84 92.0 85.5 93 87 91 84
6 93 87 92.5 85.0 93 87 92 80
Mean 94± 1 81 ±20 92±3 79± 16 91 ±4 81 ±13 86±7 69 ±15
Ventilation (room air)
1 92 91 90.5 90.0 89 89 89 87
2 95 88 94.5 88.5 93 86 93 84
3 98 93 97.5 92.5 97 91 97 85
4 97 86 95.5 83.5 96 85 94 80
5 95 93 97.0 89.0 93 89 92 86
6 95 87 94.5 84.5 93 76 90 87
Mean 95 ±2.3 90±3 95 ±2.8 89±3 94±3 88±2 93±3 84±3
Postventilation (room air)
1 94 70 90.5 72.0 90 83 96 34
3 97 89 95.5 83.5 93 91 97 65
4 94 75 92.0 77.0 92 88 95 65

Table 4—Tratmxtianeous CO, During Sleep at Baseline Unassisted, during Ventilation, and on the First Postventilatory Night Following 12 Weeks cf Nocturnal Ventilation

Awake Stage 1 and 2 SWS REMS
ID Mean High Mean High Mean High Mean High
Baseline (oxygen)
1 50 62 63.5 66.5 68 69 69 75
2 122 148 129.0 152.0 120 137 139 151
3 96 105 91.5 101.0 92 99 103 110
4 67 79 69.5 80.5 70 76 68 77
5 70 108 82.5 92.5 88 99 108 115
6 49 54 49.0 53.0 50 51 54 57
Mean 83 ±26 100 ±33 87 ±26 99 ±33 88 ±21 96 ±27 97 ±30 106 ±31.3
Ventilation (room air)
1 43 51 44.0 49.0 50 52 49 55
2 45 50 43.5 44.5 47 47 47 50
3 55 58 51.5 58.0 48 54 54 60
4 52 61 62.0 67.0 62 68 64 70
5 51 62 58.5 62.0 62 62 64 65
6 39 41 39.5 42.5 41 44
Mean 49 ±5* 56 ±6* 52 ±8 56±9 54 ±8* 57 ±8* 56 ±8* 60 ±8*
Postventilation (room air)
1 51 58 51.5 61.5 50 54 56 62
3 48 53 53.0 55.5 54 57 55 58
4 63 65 63.5 66.5 63 64 68 70

Figure-1

Figure 1. Recorder tracing in a patient with kyphoscoliosis (subject 2). The channels show from top to bottom: electroencephalogram (EEG), electroocculogram (EOG), submental electromyogram (EMG), electrocardiogram (ECG), excursion of the rib cage (RC), the abdomen (ABD), and the sum (Vt) and arterial saturation (SaO*). The panel shows unassisted ventilation while receiving supplemental oxygen at 2 L/min via nasal prongs. Note that the pattern of breathing is rapid and shallow with little rib cage excursion. During REM sleep there is a further reduction in rib cage excursion associated with a reduction in the abdominal excursion resulting in hypoventilation to the point of central apnea.

Figure-2

Figure 2. Recorder tracing from the same subject as in Figure 1. The subject is now breathing room air and receiving intermittent positive pressure ventilation via a nasal mask. Abbreviations are as in Figure 1 (Pvent=pressure generated by positive pressure ventilator). Note that during wakefulness, slow wave sleep, and REM sleep, tidal volume is increased as compared with that of the control night and saturation remains close to 95 percent.

This entry was posted in Pulmonary function and tagged inspiratory muscle, kyphoscoliosis, positive pressure ventilation, respiratory failure.
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