Medicine of the Future in America

Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: Analysis

Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: AnalysisThis patient was excluded from further analysis. In the COPD group, six patients were successfully weaned whereas in three patients, the ALV controller maintained pressure support respiration and these were documented as having failed the wean. However, apart from the patient in the pulmonary parenchymal group who was unable to be assessed, the patients in the three groups who failed the weans at the time of this study were subsequently weaned from ventilatory support and recovered from their acute disease that had caused the respiratory failure. Table 3 shows a comparison between the successful and failed wean cases at baseline. The differences seen in Pawmax, Rtot, P0.1, IPD, PE, and VdS were not statistically significant. Table 4 and Figure 3 show that the ALV controller reduced the APinsp to 5 cm H2O in the successfully weaned patients but maintained an elevated pressure support level in all but one patient who failed to wean. generic yaz

Differences were recorded in the index of airway resistance relative to muscular activity (Rtot), the respiratory drive (P0.1), the IPD, and the pressure time product (PE) as well as the slope of the CO2 curve between the failed and successfully weaned patients. However, the differences did not reach statistical significance and the null hypotheses was accepted for these parameters.
None of the patients studied complained of any discomfort during their weaning by the ALV controller and none reported shortness of breath in the phase when the ALV controller reduced their respiratory support. Continuous pulse oximetry confirmed adequate saturation in all patients during the wean and no adjustments of inspired oxygenation or PEEP were required. Routine monitoring of heart rate, rhythm, and end-tidal CO2 ensured that no patients were placed at risk during the studies.

Table 3—Selected Baseline Data: Median Values for Successful vs Failed Wean Patients (n=26)

No. PaC02,kPa Pa02,kPa fmech,/min fspont,/min Vt,mL Vmin,L/min Pawmax,cmH20 Paw-ee,cnH20 vc,mL
Successful 21 4.25 20.5 10 4 542 8.8 23.9 5 1100
Failed 5 4.55 12.1 12 0 602 8.1 31.7 3 900
Rtot,cm

/L/sec

Ctot,mL/cm

h2o

P0.1,cmH20 RC, s IPD,mj PE,Ns/m2 VdS,mL V’gA,L/min FetC02,vols% slopeC02, vols%/L
Successful 7.1 61 -0.46 0.75 14.95 72 99 6.9 3.62 2.41
Failed 14.3 41 2.3 0.63 1.3 7 139 5.8 3.91 2.88

Table 4—Selected Data: Median Values for Patients at 2 h (n=26)

Outcome No. PaC02,kPa Pa02,kPa fmech,/min fspont,/min Vt,mL Vmin,L

/min

RSB,/min

/mL

Pawmax, Paw-ee, cm cnн2о н2о
Normal Success 8 3.9 20.9 4 13 380 7.1 0.042 10.6 5.8
Failed 1 4.9 19.7 4 15 318 6 0.059 15.2 10
Parenchymalabnormality Success 7 4.4 18.8 4 19 363 9.8 0.077 13.5 7.8
Failed 1 3.98 14 4 41 391 17.8 0.12 33.5 7.3
COPD Success 6 4.9 14.9 4 16 390 8.6 0.045 8.7 2.4
Failed 3 5.35 13 4 18 339 8.7 0.06 13.2 0
Success vs failed NS NS NS NS NS NS NS NS NS
APinsp,cm

h2o

Rtot,cm

H2

O/L/s

P0.1,cm

h2o

RC,s IPD,mj PE,Ns

/m2

VdS,mL V’gA,L

/min

FetC02,vols% slopeco2,

vols%

/L

Normal 5 0.51 -1.2 0.8 14.6 94 63 5.8 4.3 2.7
5 1.7 -0.9 0.85 3.93 38 98 4.2 4.8 7.27
Parenchymalabnormality 5 -1.3 -2.4 0.71 27.3 88 101 6.6 3.63 4.3
20.2 5.5 -3.38 0.36 13.41 36 164 10.3 3.0 5.67
COPD 5 -0.6 -1.5 0.7 25.3 87 73 6.8 3.92 4.15
12 10 +3 0.52 1.97 16 121 5.6 4.03 6.76
Success vs failed p<0.05 p<0.05 NS NS NS NS NS NS NS p<0.05

Figure-3

Figure 3. Pressure support levels in successful vs failed cases of weaning.

This entry was posted in Pulmonary function and tagged chronic obstructive lung disease, feedback, mechanical ventilation, respiratory failure, weaning.
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