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Biomedical subjects

N Lampron

Publications and source records attributed to N Lampron.

14 recordsLinked to original sources
PubMed2005

Human metapneumovirus infection in adults with community-acquired pneumonia and exacerbation of chronic obstructive pulmonary disease.

We tested nasopharyngeal aspirate specimens by real-time polymerase chain reaction assays and paired serum samples by enzyme-linked immunosorbent assays. Acute human metapneumovirus infections were identified in 6 (4.1%) of 145 adult patients who presented to the emergency department for pneumonia or acute exacerbation of chronic obstructive pulmonary disease during 2 winter/spring seasons in Quebec, Canada.

Adult↗
PubMed2000

Transtracheal air in the treatment of obstructive sleep apnoea hypopnoea syndrome.

A 49 year old woman with typical obstructive sleep apnoea hypopnoea syndrome underwent an unsuccessful trial with continuous positive airway pressure (CPAP) followed by uvulopalatopharyngoplasty with septorhinoplasty, treatment with protriptyline, and a second CPAP trial that was abandoned. Transtracheal air was then given and normalised sleep and breathing at a flow rate of 5 l/min. A sustained clinical improvement was observed at follow up visits. Transtracheal air could represent a simple and effective alternative to tracheotomy in patients with obstructive sleep apnoea hypopnoea syndrome in whom conventional treatments fail.

Female↗
PubMed1999

Economic evaluation of ciprofloxacin compared with usual antibacterial care for the treatment of acute exacerbations of chronic bronchitis in patients followed for 1 year.

OBJECTIVE: To undertake a 1-year prospective economic evaluation of ciprofloxacin compared with usual antibacterial care (any antibacterial other than a quinolone) for the treatment of acute exacerbations of chronic bronchitis (AECB) in adults presenting with a type I or type II AECB. DESIGN: Patients entered the study with an initial AECB and were randomised to the ciprofloxacin group or the usual care group. The following measurements were taken at the end of each AECB and every 3 months: resource utilisation, St. George's Respiratory Questionnaire, Nottingham Health Profile and Health Utilities Index (HUI). The following additional measurements were taken after each AECB: AECB-symptom days and willingness to pay to avoid the AECB. Economic evaluations were performed from the societal viewpoint and the viewpoint of a major third-party payer. Cost-effectiveness analysis was based on cost per AECB-symptom day averted; cost-utility analysis (CUA) was based on cost per quality-adjusted life-year (QALY) gained using the HUI as the basis for calculating QALYs. Cost-benefit analysis was based on the willingness-to-pay (WTP) data. SETTING: This was a study of outpatients enrolled from 46 family physicians and 2 respirologists in Ontario (29 sites) and Québec (19 sites), Canada, between November 1993 and June 1994. PATIENTS AND PARTICIPANTS: 240 adult male and female patients aged > or = 18 years with chronic bronchitis. MAIN OUTCOME MEASURES AND RESULTS: WTP data did not pass scope tests for reasonableness. Ciprofloxacin was more costly and provided better outcomes compared with usual antibacterial care. The base-case results are as follows (1994/1995 values): the incremental annual cost was 578 Canadian dollars ($Can) from the societal viewpoint and $Can840 for the third-party payer; the cost-effectiveness ratio per AECB-symptom day averted was $Can209 from the societal viewpoint and $Can304 for the third-party payer; the cost-utility ratio per QALY gained was $Can18,600 from the societal viewpoint and $Can27,000 for the third-party payer. According to Laupacis criteria, these CUA results are strong evidence in favour of adoption from the societal viewpoint and moderate evidence in favour from the viewpoint of the third-party payer. A subgroup analysis suggests that ciprofloxacin may be particularly cost effective, even 'win-win', in patients with more severe disease. CONCLUSIONS: The sensitivity analyses indicate that the results are relatively robust. Nevertheless, the statistical uncertainty in the results is sufficient that the findings cannot be accepted unequivocally. A further study with a larger sample size would be useful to confirm (or deny) the findings of this study.

Adult↗
PubMed1998

A 1-year community-based health economic study of ciprofloxacin vs usual antibiotic treatment in acute exacerbations of chronic bronchitis: the Canadian Ciprofloxacin Health Economic Study Group.

OBJECTIVE: To evaluate the costs, consequences, effectiveness, and safety of ciprofloxacin vs standard antibiotic care in patients with an initial acute exacerbation of chronic bronchitis (AECB) as well as recurrent AECBs over a 1-year period. DESIGN: Randomized, multicenter, parallel-group, open-label study. SETTING: Outpatient general practice. PATIENTS: A total of 240 patients, 18 years or older with chronic bronchitis, with a history of frequent exacerbations (three or more in the past year) presenting with a type 1 or 2 AECB (two or more of increased dyspnea, increased sputum volume, or sputum purulence). MAIN OUTCOME MEASURES: The assessment included AECB symptoms, antibiotics prescribed, concomitant medications, adverse events, hospitalizations, emergency department visits, outpatient resources such as diagnostic tests, procedures, and patient and caregiver out-of-pocket expenses. Patients completed the Nottingham Health Profile, St. George's Respiratory Questionnaire, and the Health Utilities Index. The parameters were recorded with each AECB and at regular quarterly intervals for 1 year. These variables were compared between the ciprofloxacin-treated group and the usual-care-treated group. RESULTS: Patients receiving ciprofloxacin experienced a median of two AECBs per patient compared to a median of three AECBs per patient receiving usual care. The mean annualized total number of AECB-symptom days was 42.9+/-2.8 in the ciprofloxacin arm compared to 45.6+/-3.0 days in the usual-care arm (p=0.50). The overall duration of the average AECB was 15.2+/-0.6 days for the ciprofloxacin arm compared to 16.3+/-0.6 days for the usual-care arm. Treatment with ciprofloxacin tended to accelerate the resolution of all AECBs compared to usual care (relative risk=1.20; 95% confidence interval [CI], 0.91 to 1.58; p=0.19). Treatment assignment did not affect the interexacerbation period but a history of severe bronchitis, prolonged chronic bronchitis, and an increased number of AECBs in the past year were associated with shorter exacerbations-free periods. There was a slight, but not statistically significant, improvement in all quality of life measures with ciprofloxacin over usual care. The only factors predictive of hospitalization were duration of chronic bronchitis (odds ratio=4.6; 95% CI, 1.6, 13.0) and severity of chronic bronchitis (odds ratio=4.3; 95% CI, 0.8, 24.6). The incremental cost difference of $578 Canadian in favor of usual care was not significant (95% CI, -$778, $1,932). The cost for the ciprofloxacin arm over the usual care arm was $18,588 Canadian per quality-adjusted life year gained. When the simple base case analysis was expanded to examine the effect of risk stratification, the presence of moderate or severe bronchitis and at least four AECBs in the previous year changed the economic and clinical analysis to one favorable to ciprofloxacin with the ciprofloxacin-treated group having a better clinical outcome at lower cost ("win-win" scenario). CONCLUSIONS: Treatment with ciprofloxacin tended to accelerate the resolution of all AECBs compared to usual care; however, the difference was not statistically significant. Further, usual care was found to be more reflective of best available care rather than usual first-line agents such as amoxicillin, tetracycline, or trimethoprim-sulfamethoxazole as originally expected. Despite the similar antimicrobial activities and broad-spectrum coverage of both ciprofloxacin and usual care, the trends in clinical outcomes and all quality of life measurements favor ciprofloxacin. In patients suffering from an AECB with a history of moderate to severe chronic bronchitis and at least four AECBs in the previous year, ciprofloxacin treatment offered substantial clinical and economic benefits. In these patients, ciprofloxacin may be the preferred first antimicrobial choice.

Adolescent↗
PubMed1990

Influence of natural antigenic exposure on bronchoalveolar lavage in subjects with pollen-induced rhinitis.

To determine if atopic subjects without asthma naturally exposed to antigens to which they are sensitized demonstrate evidence of lower airway inflammation, we studied 10 subjects with recurrent seasonal allergic rhinitis to pollens. Each subject had a monthly methacholine challenge and two bronchoalveolar lavages (BAL), one during symptoms of allergic rhinitis and one out of season. The percentage of macrophages, lymphocytes, neutrophils, eosinophils, and mast cells in the lavage fluid were determined on Diff-Quik, nonspecific esterase, or toluidine blue-stained cytocentrifuge preparations. The total number of cells recovered on BAL was 23.2 +/- 3.5 X 10(6) (mean +/- SEM) (13.3 +/- 2.3 X 10(4) cells per milliliter) in season, during symptoms of allergic rhinitis, and 33.8 +/- 7.4 X 10(6) (15.2 +/- 3.1 X 10(4) cells per milliliter) out of season (p greater than 0.05). BAL cell-differential counts (percent) in/out season were similar for macrophages (89.0/84.6), lymphocytes (9.1/12.8), neutrophils (1.3/2.1), eosinophils (0.5/0.5), epithelial cells (0.37/0.46), and mast cells (0.0008/0.0013). Blood eosinophil counts, taken, respectively, in and out of season, were 135.5 +/- 26.8 X 10(6)/L and 102.8 +/- 20.6 X 10(6)/L (p greater than 0.05). Although overall airway responsiveness increased slightly during the pollen season, it did not reach statistical significance (geometric mean of provocative concentration causing a 20% fall in FEV1 [milligrams per milliliter], 98.8 during antigenic exposure compared to 121.4 out of season) (p greater than 0.05. These observations suggest that in subjects without asthma, no changes in cell differential are detected on BAL at the time of maximal symptoms of allergic rhinitis.

Adult↗
PubMed1990

Comparative effects of dilevalol and atenolol on lung function and airway response to methacholine in hypertensive subjects.

1. In this double-blind randomized study, after a 4-weeks placebo period, 18 patients with mild to moderate primary hypertension were assigned to treatment with either dilevalol (n = 9) daily or atenolol (n = 9) over a period of 3 months. 2. Expiratory flows, lung volumes and airway responsiveness (AR) to methacholine were assessed at the end of the placebo period and after an active treatment of 12 weeks. Blood pressure (BP), heart rate (HR) and ECG were monitored during the methacholine challenges. Twice daily peak expiratory flow rates and respiratory symptoms were recorded on a diary card. 3. No significant effects on ECG, HR and BP were observed after methacholine inhalation. In all but one subjects there was no significant change in expiratory flows, lung volumes or AR throughout the study. Mean FEV1, FVC, PEFR, FRC and PC20 methacholine were unchanged after 3 months of treatment, and not statistically different between patients on dilevalol or atenolol. 4. One subject, without previous history of asthma, developed transient airflow obstruction 8 weeks after beginning dilevalol. 5. Dilevalol and atenolol have no significant effects on pulmonary function and AR in most subjects with no baseline airflow limitation. 6. Airflow obstruction may develop in normal subjects on dilevalol. Methacholine challenges are safe in subjects with uncomplicated hypertension.

Adult↗
PubMed1989

Pulmonary function and airway responsiveness during long-term therapy with captopril.

Angiotensin-converting enzyme inhibitors sometimes cause cough; the mechanism is unknown. We therefore studied the effects of ambulatory treatment with captopril on pulmonary function and on nonspecific bronchial responsiveness to methacholine in 15 hypertensive subjects. Lung volumes, expiratory flows and nonspecific bronchial responsiveness to methacholine using doses up to 64 g/L were measured before and four and eight weeks after captopril treatment was started. Throughout the study the subjects recorded respiratory symptoms and peak expiratory flow rates. In four subjects a persistent cough developed related to the use of captopril, but this was not associated with the development of airflow obstruction or bronchial hyperresponsiveness. The mean provocative concentration of methacholine that resulted in a 20% fall in the forced expiratory volume in 1 s was 43.6 +/- 1.8 g/L after eight weeks of captopril treatment compared with 61.6 +/- 1.2 g/L at the baseline evaluation. We concluded that there was no significant change in lung function during treatment with captopril. The development of a cough related to this medication is not associated with the development of airflow obstruction or airway hyperresponsiveness.

Aged↗
PubMed1989

Influence of lung volume in sleep apnoea.

The influence of a constant increase in functional residual capacity on apnoea characteristics was studied in patients with the sleep apnoea syndrome. Pulmonary inflation was achieved by applying a continuous negative extrathoracic pressure into a Poncho type respirator. Nine patients slept in the Poncho for two consecutive nights, negative extrathoracic pressure being applied during the second night. There was no difference in the total sleep time, its composition within the different sleep stages, the apnoea and apnoea-hypopnoea indices, or the sleep time spent in apnoea between the two nights. The mean (SD) apnoea duration increased with negative extrathoracic pressure from 25.3 (2) to 30.5 (3) seconds (p = 0.003) and time spent in obstructive apnoea (percentage of apnoea time) from 56 (13) to 75 (8) (p = 0.02). The mixed apnoea time (%) decreased from 37 (7) to 21 (7) (p = 0.02). Despite the increase in apnoea duration, less time was spent below each oxygen saturation value during negative extrathoracic pressure. The results were similar for apnoeic episodes during non-REM (non-rapid eye movement) sleep, whereas no significant modifications were seen during REM sleep. It is concluded that the composition of apnoea time and resulting oxygen desaturation are influenced by lung volume.

Humans↗
PubMed1988

Increasing the functional residual capacity may reverse obstructive sleep apnea.

We describe the reversal of obstructive sleep apnea with a 0.5 L increase in the functional residual capacity (FRC) in a patient with sleep apnea syndrome. The patient had been treated with medroxyprogesterone acetate for 8 months. The increase in FRC was obtained by applying a constant negative extrathoracic pressure (NEP) with a poncho-type respirator. With pulmonary inflation, there was a dramatic decrease in the apnea index and the percent apnea time, and an improvement in sleep architecture. At all sleep stages, the desaturation duration was shorter with NEP. The exact mechanisms by which pulmonary expansion improved sleep apnea in this patient remain unclear; lung volume dependence of upper airway patency and the improvements in apnea-induced desaturation may be contributing factors. Our observation illustrates that lung volumes may be an important factor in the pathophysiology of obstructive sleep apnea, especially in the apnea onset and in the apneic-induced desaturation.

Airway Obstruction↗
PubMed1985

Mechanical ventilation with 100% oxygen does not increase intrapulmonary shunt in patients with severe bacterial pneumonia.

Pure oxygen ventilation has been shown to increase the right to left shunt QS/QT in both normal and diseased lungs. Nitrogen absorption atelectasis, an explanation of the phenomenon, is likely to occur in lung units with low ventilation/perfusion ratio. In 11 patients with severe unilateral or bilateral bacterial pneumonia, we assessed the effects of increasing FlO2 from maintenance level (m = 0.44 +/- 0.11) to 1.0. Venous admixture (QVA/QT) was calculated using the O2 method, and the distribution of the VA/Q ratios were assessed with the 6 inert gas (IG) technique providing the distribution between the true shunt (QS/QT IG) and the low VA/Q units. Although a large part of perfusion was distributed preferentially to low VA/Q units, ranging from 2 to 43% of cardiac output, thus placing large zones of lung parenchyma at risk of absorption atelectasis, QVA/QT decreased from 31 +/- 13% to 25 +/- 10% and IG shunt did not increase after 30 min of O2 ventilation. In addition, QS/QT IG remained unaltered despite PVO2 increased from 32 to 43 mmHg, suggesting a poor level of hypoxic vasoconstriction in human bacterial pneumonia.

Bacterial Infections↗
PubMed1984

[Acute respiratory distress syndrome in the adult. Distribution of the ventilation-perfusion ratio].

Hypoxemia in the acute respiratory distress syndrome may be due to a variety of causes: trùe pulmonary shunt, decreased ventilation/perfusion ratios, impaired diffusion and/or fall of mixed venous oxygen. In order to sort out these different tension mechanisms, 18 patients with acute respiratory distress syndrome were explored by the inert gas method. In 6 of them hypoxemia was due to a true shunt (35 +/- 10%). The remaining 12 patients also had a true shunt (26.5 +/- 9.5%), but 4.5% of the cardiac output was distributed to areas with a ventilation/perfusion ratio between 0.1 and 0.005. Thus, in these 18 patients with acute respiratory distress, hypoxemia could be explained essentially by a true shunt.

Adult↗
PubMed1984

Common carotid haemodynamic and metabolic effects of acutely administered nifedipine in human subarachnoid haemorrhage.

Although the drugs known as "calcium antagonists" exert inhibitory actions on vascular smooth muscle, there are no quantitative data concerning the clinical use of these vasodilator agents in human subarachnoid haemorrhage. In the present clinical study, we have measured the effects of nifedipine (20 mg tablet) on common carotid artery diameter (D) blood flow velocity (V) common carotid blood flow (CCBF) as an index of cerebral blood flow, systolic (Qs) and diastolic (Qd) blood flow fractions using a pulsed Doppler apparatus and on carotid arterial pressure (CAP), heart rate (HR) and oxygen consumption (VO2). Eight patients with subarachnoid haemorrhage were studied during anaesthesia for cerebral angiography. Thirty minutes after sublingual nifedipine, diameter (P less than 0.05), blood flow velocity (P less than 0.001), CCBF (P less than 0.001), Qs (P less than 0.05), and Qd (P less than 0.05) increased with a decrease in Qs/Qd ratio (P less than 0.05). carotid vascular resistance (CVR) fell (P less than 0.02) and oxygen consumption of the brain increased (P less than 0.01). Systolic, diastolic, and mean carotid blood pressure, heart rate, and arteriovenous difference in oxygen were unchanged. The increase in CCBF was closely correlated with the vascular resistance in the control state (r = 0.928, P less than 0.001) and with oxygen consumption (r = 0.869, P less than 0.001). We conclude that in vivo, nifedipine exerts a preferential action on cerebral vessels, vasodilating large arteries and arterioles. This action is more powerful if the vessels are already vasoconstricted. Thus, the use of nifedipine could be fruitful in cerebral ischaemia that is secondary to subarachnoid haemorrhage.

Adult↗
PubMedDate not supplied

Intrapulmonary shunt is not increased by 100% oxygen ventilation in acute respiratory failure.

Increase of shunt has been demonstrated during short periods of pure oxygen breathing, mostly in patients with mild acute respiratory failure (ARF). Twenty patients with a large range of venous admixture (12 to 63%) were studied when FIO2 was increased from maintenance to one. Intrapulmonary shunt was measured with both the conventional oxygen method [QS/QT (O2)] and the multiple inert gas elimination technique [QS/QT (IG)]. Mean venous admixture decreased from 29 to 24% when FIO2 was increased and QS/QT (IG) remained unaltered. The pattern of blood flow distribution remained similar in both conditions, even in the eleven patients with ARF secondary to bacterial pneumonia and who had a low V/Q mode, highly liable to collapse with 100% oxygen. As no increase in shunt was documented in these patients, reluctance to measure shunt during 100% oxygen breathing should be re-evaluated.

Acute Disease↗