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Biomedical subjects

M El-Khatib

Publications and source records attributed to M El-Khatib.

7 recordsLinked to original sources

Pattern of spontaneous breathing: potential marker for weaning outcome. Spontaneous breathing pattern and weaning from mechanical ventilation.

OBJECTIVE: To quantitatively assess the spontaneous breathing (SB) pattern, during minimal ventilatory support, of patients who pass or fail weaning trials from mechanical ventilation. DESIGN: A prospective, clinical trial. SETTING: Intensive care unit of a university teaching hospital. PATIENTS: Fifty-two tracheally intubated and hemodynamically stable patients who were judged clinically ready for extubation. METHODS: Using a computerized respiratory profile monitor, continuous respiratory parameters were obtained while patients were receiving four or less synchronized intermittent mandatory (SIMV) breaths and during CPAP trials. Coefficients of variation (CV) of spontaneous tidal volumes and flows during SIMV trials as well as the entropies and dimensions of the breathing patterns during CPAP trials were used to assess the dynamical breathing behaviors of the patients who passed or failed weaning trials. MEASUREMENTS AND RESULTS: Thirty-nine extubations were successful and 13 were not. The CV of the spontaneous tidal volumes (VT) and the spontaneous peak inspiratory flows (PF), the Kolmogorov entropy and the dimension of the SB patterns were compared in the two groups. The CV of VT (9.13 +/- 4.11 vs 26.07 +/- 6.94), the CV of PF (11.63 +/- 4.18 vs 29.88 +/- 12.07), the Kolmogorov entropy (0.09 +/- 0.03 bits/cycle vs 0.39 +/- 0.09 bits/cycle), and the dimension of the SB pattern (1.33 +/- 0.07 vs 3.93 +/- 0.47) were all significantly smaller (P < 0.05) in the successfully extubated group versus the group that failed extubation. CONCLUSION: The spontaneous breathing pattern during minimal mechanical ventilatory support is more chaotic in patients who failed extubation trials compared to patients who passed extubation trials. Thus, we speculate that characterizing the SB pattern during minimal ventilatory support might be a useful tool in differentiating between extubation success and failure.

Adult↗

Apnea-induced hemoglobin desaturation during one-lung vs two-lung ventilation.

PURPOSE: To compare the rate of apnea-induced hemoglobin desaturation during one-lung ventilation (OLV) vs. two-lung ventilation (TLV) in patients undergoing thoracic surgery. METHODS: Six patients undergoing thoracotomy or thoracoscopy were included. Each patient served as his/her own control. The lungs were ventilated with oxygen 100% using TLV, followed after 20-30 min by OLV and the resultant PaO2 was measured. Apnea was then induced following the two techniques of ventilation, and the times for every 1% decrease in hemoglobin saturation from 100% to 95%, as monitored by pulse oximetry, were recorded. The times for every 1% decrease in the saturation were compared in the two groups. RESULTS: The mean PaO2 value following TLV (445+/-99 mm Hg) was higher than the mean PaO2 following OLV (156+/-18 mm Hg). Also, the mean time for subsequent apnea induced hemoglobin desaturation from SpO2 100% to 95% following TLV was twice the time of desaturation following OLV (6.3+/-1.2 min vs. 3.2+/-0.5 min, P<0.05). CONCLUSION: Hemoglobin desaturation occurs more rapidly during apnea following OLV than TLV. The rapid desaturation may be attributed to the decrease of FRC, associated with an increased transpulmonary shunting. The results suggest that two-lung ventilation with oxygen 100% provides a greater safety margin than one-lung ventilation with oxygen 100% whenever ventilation is interrupted.

Adult↗

Treatment of severe status asthmaticus with nitric oxide.

The paper reports on a 13-year-old girl with chronic asthma who presented in acute respiratory failure following an exacerbation of her disease. Nitric oxide was added to the ventilator circuit at 7 ppm and then 15 ppm after the patient failed to respond to bronchodilators and steroids. This was followed by rapid improvement in respiratory mechanics and blood gases with no adverse effects. Nitric oxide appears to have a direct relaxing effect on the bronchial smooth muscle.

Administration, Inhalation↗

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Journal Article↗

Fas (CD95)/Fas ligand interactions regulate antigen-specific, major histocompatibility complex-restricted T/B cell proliferative responses.

The effect of Fas ligand (FasL) cytotoxicity on T/B collaboration was examined in vitro using cloned T helper 1 cells and antigen-pulsed, activated B cells. We compared antigen-pulsed B cells that had been activated through different membrane receptors (IgM, CD14 and CD40) for their ability to induce T cell proliferation and to respond to T cell help. We also used a Fas-Ig fusion protein, an inhibitor of FasL-mediated cytotoxicity, to determine the effect of FasL cytotoxicity on the T and B cell proliferative responses. The data show that the extent of both T and B cell proliferative responses correlate with the relative resistance of activated B cell populations to FasL cytotoxicity. Moreover, both T and B cell proliferation could be enhanced by Fas-Ig. Our results demonstrate that FasL cytotoxicity is a negative regulatory mechanism for both T and B cell proliferative responses and that Fas-Ig can be an immunopotentiating agent for both T and B cell immunity.

Animals↗