Biomedical subjects

Y Cormier

Publications and source records attributed to Y Cormier.

At least 73 records · Page 4Linked to original sources

PubMed1994

Influence of lung volume on collateral resistance during methacholine-induced bronchospasm.

We tested the hypothesis that lung inflation in response to a bronchospasm could be beneficial by maintaining the lung collateral channels open. Six mild asthmatics were studied on 2 separate days. The first day we determined the methacholine dose response and measured collateral resistance (Rcoll) before and during the metacholine-induced bronchospasm and the effects of decreasing lung volumes on Rcoll. The lung volume changes were induced by applying progressively increasing positive extrathoracic pressures (PEP). The second day we measured the changes in end-expiratory lung volume (EELV) resulting from the inhaled methacholine and from the applied positive extrathoracic pressure. With the inhalation of methacholine, the FEV1 decrease ranged from 26-43% of the baseline values while Rcoll increased significantly in only three of the six subjects. EELV remained unchanged in one subject and increased by 1408, 990, 260, and 44 ml in four others. It was not measured in one subject. Decreasing EELV by PEP increased Rcoll in all subjects. By extrapolation of the lung volume-Rcoll relationship, we calculated that Rcoll would have increased by 18,227%, 6843%, 994%, 140%, and 128% if EELV had not increased in the five subjects in whom delta EELV was measured. We conclude that an increase in EELV in response to an induced bronchospasm helps maintain open and functional collateral pathways despite the bronchoconstriction.

Adult↗

PubMed1994

Long-term viral enhancement of lung response to Saccharopolyspora rectivirgula.

The current study was done to look at the long-term enhancing effect of a single viral infection on repeated Saccharopolyspora rectivirgula (SR) antigenic challenges in mice and at inflammatory cytokines in this enhancement. Four groups of C57BI/6 mice were studied: Group 1 received intranasal instillations of saline, 3 days per week; Group 2, intranasal instillations of saline plus one intranasal instillation of 80 hemagglutination units (HAU) of Sendai virus after 3 wk of saline; Group 3, instillations of SR, 3 days per week; and Group 4, instillations of SR, 3 days per week, plus one instillation of Sendai virus after 3 wk of SR. Bronchoalveolar lavages (BAL) were performed 15 and 30 wk after the virus inoculation in the appropriate groups. Each time, a two- to threefold increase in BAL cell counts was obtained from virus-infected animals challenged with SR compared with animals that received the SR alone. Animals infected with virus only showed values similar to those of control animals. A higher percentage of large foamy multinucleated cells were found in the BAL from the SR+Sendai group than the SR alone group (7.92 +/- 0.730% compared with 1.8 +/- 0.296%). These cells were not seen in the other groups. BAL levels of TNF-alpha and IL-1 alpha at 15 wk were much higher in SR+Sendai-treated (1,439 +/- 268 and 96 +/- 9 pg/ml, respectively) than SR alone-treated animals (361 +/- 100 and 23 +/- 4 pg/ml). BAL fluid of control animals and Sendai alone animals contained 64 +/- 24 and 65 +/- 15 pg/ml of TNF-alpha, but no IL-1 alpha was detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Required levels of nasal continuous positive airway pressure during treatment of obstructive sleep apnoea.

The improvement in the severity of obstructive sleep-related breathing disorders during nasal continuous positive airway pressure (NCPAP) therapy can account for the decrease in the required NCPAP level with time. The aim of this study was to prospectively quantify the changes in the required NCPAP level over time of use in sleep apnoea-hypopnoea syndrome (SAHS). Forty sleep apnoea-hypopnoea patients were evaluated before and during the time course of NCPAP therapy. The effective NCPAP level was defined as the positive pressure level that abolished apnoeic and hypopnoeic events and snoring in all sleep stages and sleep positions. This pressure level was determined within 2 weeks after baseline diagnostic sleep study. Sleep studies with NCPAP and NCPAP titration were performed after 2 (n = 40), 8 (n = 40), and 20 (n = 24) months of NCPAP therapy. The initial effective NCPAP level was 9.6 +/- 0.4 cmH2O. It progressively decreased to 8.8 +/- 0.4, 7.9 +/- 0.4 and 7.7 +/- 0.5 after 2, 8 and 20 months, respectively; the difference being significant between the first three NCPAP nights. There was a poor relationship between the changes in the effective NCPAP and changes in weight recorded at the different visits. There was a weak negative relationship between the changes in NCPAP and the previous NCPAP level. In 13 patients, the apnoea-hypopnoea index (AHI) remained > 10 n.h-1 at the first NCPAP trial because the effective NCPAP level was not tolerated. Despite a suboptimal NCPAP level, their sleep architecture improved, and they all reported a subjective improvement in diurnal hypersomnolence.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Utility of nocturnal home oximetry for case finding in patients with suspected sleep apnea hypopnea syndrome.

OBJECTIVE: To evaluate prospectively the validity of home oximetry for case finding in patients clinically suspected of having the sleep apnea hypopnea syndrome (SAHS). DESIGN: Blinded comparison of home oximetry and polysomnographic nocturnal recordings. SETTING: Sleep clinic of a tertiary referral center. PATIENTS: A total of 240 outpatients referred because of reported sleep disturbances or daytime hypersomnia compatible with the diagnosis of SAHS. MEASUREMENTS: All participants had nocturnal home oximetry followed by a conventional polysomnographic study. The two recordings were interpreted blindly. Home oximetry test results were classified as abnormal (suspicion of sleep-related breathing abnormalities) in the presence of repetitive, short-duration arterial oxyhemoglobin saturation. (SaO2) fluctuations without any absolute or relative decrease in the SaO2 threshold. The diagnosis of SAHS was confirmed when the apnea-plus-hypopnea index was greater than 10. RESULTS: Based on the results of the polysomnographic sleep study, 110 patients had SAHS (apnea-plus-hypopnea index, 38.1 +/- 2.5/h; mean +/- SE). Home oximetry test results were interpreted as abnormal in 176 patients (this included 108 patients with SAHS and 68 without SAHS) and were read as normal in 62 patients without SAHS and in 2 with SAHS. Home oximetry testing had a sensitivity of 108/110 or 98.2% (95% Cl, 93.6% to 99.8%); a specificity of 62/130 or 47.7% (Cl, 38.8% to 56.6%); a positive predictive value of 108/176 or 61.4%; and a negative predictive value of 62/64 or 96.9%. CONCLUSIONS: A negative home oximetry test result is helpful in ruling out the diagnosis of SAHS in patients clinically suspected of having this syndrome, because a negative test result reduced the probability from 54.1% to 3.1% in our patients. However, a positive oximetry test increased the probability from 46% to 61.4% in our group of patients.

Adult↗

PubMed1993

Polychemotherapy in advanced non small cell lung cancer: a meta-analysis.

We did a meta-analysis of all published polychemotherapy vs supportive care clinical trials in patients with non-resectable non small cell lung cancer. 7 studies with more than 700 patients were selected. We used the number of deaths at 3, 6, 9, 12, and 18 months as the endpoints because we were unable to obtain all the individual data. Our analysis showed a reduction in mortality during the first 6 months with polychemotherapy. Although small, this increase in survival, together with an improved quality of life, suggests that polychemotherapy should be recommended for patients with non-resectable non small cell lung cancer.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1993

Influence of lung volume hysteresis on collateral resistance in intact dogs.

Collateral resistance (Rcoll) is highly lung volume dependent. We studied 12 dogs in an attempt to evaluate the influence of hysteresis on this volume dependency. Rcoll measurements were obtained at baseline and at different lung volumes as modified by the application of negative or positive extrathoracic pressure (ETP) in an iron lung. ETP was modified in 5 cmH2O steps from +20 to -25 cmH2O) and back to +20 cmH2O on the first day (cycle 1), and, in 4 of these dogs, from -25 to +20 cmH2O and back to -25 cmH2O on a second day (cycle 2). The behavior of Rcoll for both cycles was the same in all dogs, varying inversely with the changes in end-expiratory lung volume (EELV). All dogs presented a similar pattern: during cycle 1, for a same lung volume, Rcoll was much higher during the deflation limb than during the inflation limb. For cycle 2, Rcoll at a given lung volume was similar whether measured during the inflation or deflation limb. Changes in EELV were higher for any given negative ETP during the deflation than during the inflation limb of the pressure cycles (e.g., for the 4 dogs who had both cycles, at -15 cmH2O ETP of cycle 2 the increase in EELV was 1167 +/- 121 ml during deflation and 525 +/- 102 ml during the subsequent inflation [mean +/- SEM]). In conclusion, the effects of hysteresis on Rcoll and on lung volumes are similar, except at low lung volumes during the deflation limb of cycle 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗

PubMed1993

Effect of inflammation on peripheral airway reactivity in dogs.

1. Eight mongrel dogs were studied to evaluate the effect of local inflammation on the response of collateral airways to histamine. In each dog we measured the baseline collateral resistance and its response to increasing doses of nebulized histamine. These measurements were obtained at weekly intervals, twice under control conditions and in three subsequent weeks after a local instillation of the bacteria Bordetella bronchiseptica. On each study day, after the measurements of collateral resistance, we lavaged the studied lung segment by instilling and aspirating 100 ml of saline (four 25 ml aliquots). All studies were performed in the same lung segment. 2. Collateral resistance remained stable under control conditions at 19.5 +/- 7.2 and 11.7 +/- 3.2 cmH2O l-1 min. With a bacteria-induced, mostly neutrophilic, inflammation, collateral resistance initially increased to 70.2 +/- 18.6 cmH2O l-1 min after 1 week and subsequently decreased towards control values (47.3 +/- 13 and 30.7 +/- 10.1 cmH2O l-1 min at 21 and 29 days, respectively). Collateral pathways reactivity, expressed as the slope of the relationship collateral resistance/log (1 + [histamine]), remained unchanged throughout the study. The values of this slope were (mean +/- SEM) 0.021 +/- 0.003 and 0.022 +/- 0.004 in the two control studies and 0.025 +/- 0.004, 0.030 +/- 0.006 and 0.023 +/- 0.003 in the three subsequent weekly studies. Inflammation, evaluated by the number of bronchoalveolar lavage cells and the percentage of neutrophils in bronchoalveolar cells, closely paralleled baseline collateral resistance with a peak value at the first week after the infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗

PubMed1993

Liposomal dexamethasone effectiveness in the treatment of hypersensitivity pneumonitis in mice.

The effects of daily intranasal instillation of liposomal dexamethasone and free dexamethasone phosphate were compared in a murine model of hypersensitivity pneumonitis induced by Saccharopolyspora rectivirgula (formally known as Micropolyspora faeni). After 3 weeks of antigen and liposome instillations, lung response was evaluated by bronchoalveolar lavage cell counts, lung index and histopathology. Systemic absorption was evaluated by measuring plasma adrenocorticotropic hormone (ACTH) level. Free dexamethasone phosphate induced a dose-dependent response with the maximal effect reached at 1 mg kg-1. At 0.1 mg kg-1, liposomal dexamethasone had a greater effect than free dexamethasone phosphate on bronchoalveolar cells ml-1: 3.01 x 10(5) +/- 0.35 x 10(5) compared to 4.70 x 10(5) +/- 0.34 x 10(5), and lung index: 1.22 +/- 0.10 compared to 1.86 +/- 0.07. Effect on histopathology was similar. Plasma ACTH levels (pg ml-1) were: 75.1 +/- 14.0 for animals receiving antigen and free dexamethasone phosphate (0.2 mg kg-1), and 149.7 +/- 12.0 for animals receiving antigen and liposomal dexamethasone (0.2 mg kg-1). In conclusion, liposome-incorporated dexamethasone is efficient in the treatment of experimental hypersensitivity pneumonitis and, contrarily to free dexamethasone phosphate, does not inhibit ACTH secretion.

Adrenocorticotropic Hormone↗

PubMed1993

Effect of stabling on bronchoalveolar cells obtained from normal and COPD horses.

Bronchoalveolar lavages (BAL) were performed before and after 3 weeks of housing in 5 horses suffering from COPD and 5 normal horses. In the two groups, the total number of cells recovered remained unchanged after stabling. The most common cell populations in BAL fluid of control animals were alveolar macrophages (46.4%) and lymphocytes (44.9%). The percentage of neutrophils increased after stabling from 8.7% to 27.6%. In COPD horses, lymphocytes predominated (40.7%) in animals at pasture with neutrophils increasing from 29.4% to 71.6% after stabling. After fractionation by Percoll density gradient, alveolar macrophages and neutrophils from normal and COPD horses had a similar density distribution. After stabling, these cells from normal horses were increased in the low density layers, while those from COPD horses were predominantly in the hyperdense layers. Therefore, BAL cells obtained from COPD animals at pasture and after stabling differ from those of control horses in the same environment, not only in their populations but also in their buoyant densities. These differences could be related to different states of cellular activation and perhaps be responsible for disease activity in the COPD horses.

Animals↗

PubMed1993

A study of monokine release and natural killer activity in the bronchoalveolar lavage of subjects with farmer's lung.

We examined the interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha) releasability of alveolar macrophages and the natural killer (NK) cell activity in the bronchoalveolar lavage (BAL) cells of 11 patients with Farmer's lung at different stages of the disease. Although there were some variations in the levels of monokine release, macrophages of patients with acute disease secreted significantly higher spontaneous levels of TNF alpha than did a nonfarming control group (p = 0.0002). Conversely, TNF alpha release stimulated by bacterial lipopolysaccharide (LPS) was similar in patients with acute disease when compared with that in normal control subjects. IL-1 was also spontaneously secreted in significantly greater amounts by patients with acute Farmer's lung than by subjects in a control group (p = 0.0001). However, LPS-induced IL-1 release was significantly diminished in BAL macrophages from patients with acute manifestations of the disease when compared with that in control subjects (p = 0.001). Treating hypersensitivity pneumonitis with corticosteroids or by contact avoidance resulted in very significant decrease in spontaneous and LPS-stimulated IL-1 production by BAL macrophages (p = 0.0001 and p = 0.03, respectively), as well as in a decrease in spontaneous TNF alpha release that was also significant (p = 0.01). In addition, BAL cells of patients in the acute phase had a significant NK cell activity (mean +/- SEM of 18.33 +/- 2.65%). Treatment of these patients resulted in an increase in NK cell activity (mean of 40.17 +/- 7.86%), which was significantly different from values of patients with acute disease (p = 0.037).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1993

Long-term effects of protriptyline in patients with chronic obstructive pulmonary disease.

Protriptyline has been shown to improve nocturnal and diurnal hypoxemia in patients with chronic obstructive pulmonary disease in short trials. We prospectively evaluated the long-term effects of protriptyline on pulmonary functions (lung volume and expiratory flow, arterial blood gases) and sleep characteristics (sleep architecture, nocturnal desaturations) in these patients. Sixteen patients previously studied before and after 10 wk of protriptyline treatment were reevaluated after a long-term follow-up (range, 18 to 63 months); the results of those still receiving protriptyline were compared with those who stopped using the drug. Nine patients were still receiving protriptyline at the follow-up visit (10 to 20 mg/day at bedtime), and seven had stopped using the drug because of side effects. These two groups of patients did not differ in their follow-up duration, age, weight, pulmonary functions, and sleep architecture, or in their protriptyline-induced changes in diurnal arterial blood gases and nocturnal desaturation. At the follow-up visit, arterial blood gas determinations had returned to baseline values in all patients no longer receiving protriptyline. In the other group there was no difference between the baseline and follow-up PaO2 values (57.4 +/- 3.4 and 57.0 +/- 1.2 mm Hg, mean +/- SEM). There was no difference in the results of arterial blood gas determinations and pulmonary function tests obtained at the different visits between the two groups. Sleep architecture differed between these two groups, REM sleep time being shorter and the slow-wave sleep time being longer in the patients still receiving the drug. In both groups the cumulative SaO2 curves were similar to those obtained at baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian Rhythm↗

PubMed1993

Farmer's lung. Long-term outcome and lack of predictive value of bronchoalveolar lavage fibrosing factors.

This study evaluates the long-term outcome of farmer's lung (FL), adding high-resolution computed tomograms (HRCT) to previously reported procedures and verifying whether bronchoalveolar lavage (BAL) fluid markers or substrates of fibrosis (hyaluronic acid, Type III procollagen, fibronectin, and fibroblast growth factors) (FF) predict outcome. A total of 33 subjects with a history of FL dating back at least 6 yr were evaluated with pulmonary function tests, chest x-ray (CXR), and HRCT. All subjects had an initial evaluation, which included a BAL, 6 yr before the current study. Subjects were then either in acute FL (n = 19) or in clinical remission despite continued contact (n = 14). In the current study, pulmonary function tests revealed an obstructive profile in 13 subjects, restrictive changes in 1, an isolated decrease in lung diffusion capacity in 3, and normal values in 16. Chest radiographs (CXR) were normal in 22 subjects, abnormal with interstitial or reticulonodular changes in 6, and suggestive of emphysema in 5. HRCT revealed emphysema in 9 subjects; 3 had localized fibrotic changes, 2 a ground-glass pattern, and 19 were normal. There was a good correlation between the findings on pulmonary function tests and HRCT; however, CXR alone did not suggest the existence of emphysema in 4 subjects who had such findings on HRCT. No correlations were found between most outcome parameters and the level of the BAL FF measured 6 yr previously. We conclude that airflow obstruction with or without emphysema is an important long-term sequela of FL and that BAL FF do not predict outcome in this disease.

Acute Disease↗

PubMed1993

Farmer's fever. Systemic manifestation of farmer's lung without lung involvement.

A 35-year-old dairy farmer presented with recurrent febrile episodes over more than three years. Fever up to 39 degrees C occurred only if he was in contact with the dairy barn and typically appeared at 4 to 8 h after an otherwise usual barn exposure. He had no dyspnea and throughout this period repeated physical examinations, chest roentgenograms, and lung functions remained normal. He was bronchoscoped and lavaged on three occasions, a lymphocytic alveolitis was always present and once, immediately after an acute episode, an important increase in lavage neutrophils was also found (47 percent). Transbronchial lung biopsy specimens showed a moderate cellular infiltrate but no granuloma or fibrosis. Three other persons who worked at the same farm had no similar manifestations or respiratory illnesses. The patient therefore had typical systemic manifestations of acute farmer's lung, but without the lung involvement required to confirm that diagnosis. Furthermore, his disease does not fit the entities known as grain fever and organic dust toxic syndrome. We believe that this patient presented a different entity that we coined "farmer's fever."

Adult↗

PubMed1993

Usefulness of inhaled high-dose corticosteroids in allergic bronchopulmonary aspergillosis.

Two patients with allergic bronchopulmonary aspergillosis were seen on a regular basis, one since 1978 and the other since 1982. Throughout this period, both subjects required daily oral administration of corticosteroids (between 15 and 40 mg of prednisolone daily) to control their symptoms and the lung infiltrates on the chest x-ray film. Attempts to further decrease the dosage of steroids or to discontinue their use were met with immediate recurrences of manifestations of the disease. With the introduction of high-dose inhaled beclomethasone dipropionate, both subjects could be weaned from their oral steroids and maintained with inhaled steroids alone for up to 11 months. We conclude that inhaled corticosteroids may be useful in the treatment of allergic bronchopulmonary aspergillosis.

Administration, Inhalation↗

PubMed1993

Fibrogenic activities in bronchoalveolar lavage fluid of farmer's lung.

Hyaluronic acid (HA), type III procollagen, fibronectin, and fibroblast growth factors (FGF) were measured in 43 bronchoalveolar lavage fluid (BALF) specimens obtained from 38 patients with farmer's lung (FL) and in BALF of 9 nonexposed normal control subjects. Bronchoalveolar lavage was done in 21 farmers with acute FL (acute) and in 22 with a history of previous FL (Ex) who were still in daily contact with dairy barns. All farmers from the acute and Ex groups had a lymphocytic alveolitis, respectively, 62.7 (3.5) percent (mean [SEM]) and 48.1 (4.3) percent. Hyaluronic acid, type III procollagen, fibronectin, and FGF were all highly increased in acute disease. These substances were also increased in the BALF of subjects of the Ex group who had no clinical symptoms or signs of acute disease at the time of lavage, but were actively farming. The increase in type III procollagen, however, was less in this group than in the subjects with acute disease. These observations suggest that the fibrosing activities and potentialities of the allergic alveolitis of FL are fully expressed at the time of clinical presentation and also in the subclinical phase of the disease in susceptible farmers who remain exposed after an initial acute phase of the disease.

Adult↗

PubMed1993

Murine hypersensitivity pneumonitis: evidences for the role of eicosanoids and platelet activating factor.

Eicosanoids and platelet activating factor (PAF) are involved in numerous lung diseases. However, few studies have looked for their role in hypersensitivity pneumonitis (HP). HP was induced in mice by repeated instillations of Saccharapolyspora rectivirgula (Micropolyspora faeni) during 3 weeks. Bronchoalveolar lavages (BAL) were performed each week. BAL macrophage, lymphocyte and neutrophil counts increased at week 1, for a maximal increase after 3 weeks. Production of LTB4, LTC4, PGE2 and TXB2 by alveolar macrophages stimulated in vitro with calcium ionophore was maximal after 3 weeks, the appearance of PGE2 and TXB2 preceding that of LTB4 and LTC4. Eicosanoid production by AM correlated with BAL cell counts. To look for the importance of PAF in the development of experimental HP, mice were treated with BN52021 and BN50730, two PAF antagonists, and BAL were performed after 3 weeks of treatment. The compounds BN52021 and BN50730 reduced total BAL cell counts (x 10(5) cells/ml) in animals treated with S. rectivirgula from 8.4 +/- 0.8 to 4.4 +/- 1.1 and 3.7 +/- 0.2 respectively. BAL cell numbers in control animals were 0.4 +/- 0.1. In conclusion, eicosanoids are increased in experimental HP, and, as PAF, could play a role in the accumulation of alveolar cells.

Alveolitis, Extrinsic Allergic↗

PubMed1993

Modulation of experimental hypersensitivity pneumonitis by Sendai virus.

To evaluate the potential role of viruses in the pathogenesis of hypersensitivity pneumonitis (HP), we looked at the effect of challenging normal versus Sendai-injected mice with Saccharopolyspora rectivirgula (SR). In this model of HP, mice are nasally instilled with SR antigen three consecutive days per week of study. For this study virus was given after 3 weeks of SR. Two positive (SR alone, virus alone) and a negative (saline) control groups were done in parallel with the viral plus SR group. Lung response to these different conditions was evaluated by lung index, bronchoalveolar lavage (BAL) cell populations, lung histopathology, and BAL fluid fibronectin levels. SR challenge resulted in an increase in BAL cells, lung index, and BAL fibronectin levels and in a peribronchial inflammatory reaction. The virus alone produced a transient increase in BAL cells. The cellular response to SR, in virus-injected animals, was greater than the added effects of the virus and SR. Virus alone had no persistent effect on the other measured parameters and did not change the effect of SR on these variables. We conclude that the Sendai virus enhances the cellular response of the mouse lungs to an SR antigenic challenge.

Alveolitis, Extrinsic Allergic↗

PubMed1992

Influence of continuous positive airway pressure on sleep apnea-related desaturation in sleep apnea patients.

To investigate the influence of nasal continuous positive airway pressure (CPAP) on apnea-related desaturation, we compared the sleep apnea-related desaturations obtained during a polysomnographic study before and during nasal CPAP in 15 sleep apnea patients. An individual desaturation curve was determined with a regression analysis by plotting the lowest SaO2 value reached during each apnea against its duration; these data were collected throughout the night. At baseline, we only considered the apneas with a preapneic SaO2 value greater than 90% and a minimal SaO2 value above or equal to 60%. For the CPAP study, the preapneic SaO2 value also had to be within 2% the baseline value for the apneas to be retained. Due to the restriction criteria imposed to characterize apnea-related SaO2 falls, residual apneas still had to be recorded with CPAP. These data were analyzed separately for obstructive apnea for non-rapid eye movement (REM) and REM sleep stages. A desaturation curve was obtained from 10 sec to a variable upper limit that corresponded to the longest apnea duration commonly reached during both baseline and CPAP for a given apnea-type and sleep stage. The individual apnea-related SaO2 fall was characterized by measuring a desaturation area corresponding to the area under the curve. It was expressed in % SaO2/sec of apnea. CPAP reduced the number of apneas per hour of sleep from 37.5 +/- 6.5 (mean +/- SEM) to 14.3 +/- 3.7 (p = 0.001), and improved the whole night SaO2 level as estimated by a cumulative SaO2 curve. The mean apnea duration was reduced from 22.9 +/- 1.5 sec at baseline to 16.8 +/- 0.5 sec during CPAP therapy (p = 0.005). The preapneic SaO2 value was 94.8 +/- 0.3% at baseline and 95.5 +/- 0.2% during CPAP (p = 0.5). The desaturation area decreased from 267 +/- 48% SaO2/sec at baseline to 152 +/- 41% SaO2/sec during CPAP (p less than 0.001). We conclude that CPAP improves the apnea-related desaturation independently of the shortening of apneas and of any difference in the preapneic SaO2 value.

Female↗