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Clinical Investigations in Critical CareEffects of Doxapram on Hypercapnic Response during Weaning from Mechanical Ventilation in COPD Patients
Section snippets
Patients
Thirteen patients (seven men, six women) aged 58 to 74 years (67.5 ± 6.5 years), with COPD gave their informed consent. All had a long history of chronic bronchitis and were regularly treated in the unit. Functional tests performed within four months before or after decompensation confirmed the acute obstructive syndrome. Current hospitalization was due to a bacterial infection requiring mechanical ventilation. All patients had long-term tracheostomies. Medication included feeding through a
Results
During the study, no patient showed cardiovascular or neurologic change and none of them required reinstitution of mechanical ventilation.
Results are shown in Tables 1 and 2. In a baseline state, ie, before rebreathing tests, breathing ambient air (15 min), patients were hypoxic (PaO2 = 40 ± 7.2 mm Hg; ext: 24 to 50) with variable hypercapnia (PaCO2 = 46.9 ± 6.3 mm Hg; ext = 38-64; P0.1 average was high but with strong intraindividual variations (7.9 ± 3.1 cm H2O, ext: 2.3 to 14.4; VC = 0.39).
Discussion
The results of this study bring out the following findings: (1) Response to hypercapnia is generally weak in COPD patients weaned from mechanical ventilation but there are strong individual differences.
(2) The respiratory centers can still be stimulated, as shown by the increase in P0.1d/PETCO2 in some patients, but this “overstimulation” causes an increase in the end-expiratory volume. (3) The neuromuscular and ventilatory response to hypercapnia with and without DXP does not allow prediction
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Cited by (0)
Manuscript received September 23; revision accepted January 22.
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Professor of Anesthesiology.
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Research Engineer, Staff Anesthesiologist.
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Associate Professor of Physiology.
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Staff Anesthesiologist.