Biomedical subjects

N Zamel

Publications and source records attributed to N Zamel.

At least 19 recordsLinked to original sources

PubMed2001

Exhaled nitric oxide and hydrogen peroxide in patients with chronic obstructive pulmonary disease: effects of inhaled beclomethasone.

There is controversy about the role of inhaled corticosteroids in chronic obstructive pulmonary disease (COPD). Although they appear to have little impact on airways obstruction or its progression, their use may reduce the frequency and/or severity of exacerbations in a subset of patients. We undertook the following study to determine the impact of inhaled corticosteroid on two noninvasive markers of airways inflammation. We assigned 20 stable nonsmoking patients with COPD in random, double-blind crossover fashion to two 2-wk treatment periods with inhaled beclomethasone 500 microg twice daily or matching placebo, followed by a 2-wk washout period. We measured exhaled nitric oxide (ENO), breath condensate H(2)O(2), and flow volume spirometry at weekly intervals. Median baseline ENO was 26.2 (19.3 to 54.8) ppb and fell significantly following 1 and 2 wk of beclomethasone (-10.6 ppb, p = 0.002, and -6.3 ppb, p = 0.013, respectively) but was unchanged by placebo inhalation. Breath condensate H(2)O(2) levels did not change significantly with inhaled beclomethasone or placebo. Although there were no significant changes in FEV(1) with BDP therapy, there was a moderate inverse correlation between changes in ENO and changes in FEV(1) (r -0.50). We conclude that inhaled beclomethasone reduces ENO levels in stable nonsmoking patients with COPD, a finding compatible with an antiinflammatory mechanism of action.

Administration, Topical↗

PubMed2001

Lung function 5 yr after lung volume reduction surgery for emphysema.

Current datum more than 2 yr after lung volume reduction surgery (LVRS) for emphysema is limited. This prospective study evaluates pre-LVRS baseline and 5-yr results in 26 symptomatic patients (mean age 67 +/- 6 yr) (mean +/- SD) who underwent bilateral, targeted upper lobe stapled LVRS using video-assisted thoracoscopy. Baseline forced expiratory volume in 1 s (FEV(1)) was 0.7 +/- 0.2 L (mean +/- SD), 29 +/- 10% predicted. Following LVRS, with none lost to follow-up, mortality due to respiratory failure at 0.5, 1, 2, 3, 4, and 5 yr was 4%, 4%, 19%, 31%, 46%, and 58%, respectively. Increase above baseline for FEV(1) > 200 ml and/or FVC > 400 ml at 1, 2, 3, 4, and 5 yr post-LVRS was noted in 73%, 46%, 35%, 27%, and 8% of all patients; decrease in dyspnea grade >/= 1 in 88%, 69%, 46%, 27%, and 15%; and elimination of initial oxygen dependence in 18 patients in 78%, 50%, 33%, 22%, and 0%, respectively. Expiratory airflow improved due to the increase in both lung elastic recoil and small airway intraluminal caliber. Five patients decreased FEV(1) 141 +/- 60 ml/yr and FVC 102 +/- 189 ml/yr over 3.8 +/- 1.2 yr post-LVRS, similar to their pre-LVRS rate of decline. In the 11 patients who survived 5 yr, at 0.5-1.0 yr post-LVRS peak increase in FEV(1) was 438 +/- 366 ml, with a decline of 149 +/- 157 ml the following year and 78 +/- 59 ml/yr over 4.0-4.5 yr. Bilateral LVRS provided palliative clinical and physiological improvement in 9 of 26 patients at 3 yr, 7 at 4 yr, and 2 at 5 yr.

Aged↗

PubMed2001

Exhaled nitric oxide in chronic obstructive pulmonary disease: relationship to pulmonary function.

The following study was undertaken in order to determine how exhaled nitric oxide (eNO) levels in former smokers with chronic obstructive pulmonary disease (COPD) compared to eNO levels in patients with asthma and in healthy nonsmoking volunteers. The study also aimed to determine any relationship between eNO levels in COPD and: 1) conventional measures of lung function; and 2) inhaled corticosteroid (ICS) use. In former smokers with COPD, nonsmokers with asthma and volunteers, eNO levels, spirometry, lung volumes, carbon monoxide diffusion capacity of the lung (DL,CO) and resting oxygen saturation (Sa,O2) were measured. Median eNO was significantly higher among patients with COPD than among healthy volunteers (p = 0.003) but lower than among patients with asthma (p < 0.01). There was no significant difference in eNO levels between COPD patients using ICS and those not using ICS. By contrast, eNO was lower among asthma patients who used ICS (median 32 parts per billion (ppb); 25-75% range 16-54) than among asthma patients who did not (51 ppb; 32-87) (p = 0.034). Among patients with COPD, eNO was inversely correlated with forced expiratory volume in one second, DL,CO and Sa,O2, and was positively correlated with the residual lung volume/total lung capacity ratio. Among patients with asthma, no significant correlations were found. Exhaled nitric oxide is increased in patients with chronic obstructive pulmonary disease, an increase that is influenced by structural abnormalities of tobacco-induced lung damage.

Administration, Inhalation↗

PubMed2001

Dose-response relationship and reproducibility of the fall in exhaled nitric oxide after inhaled beclomethasone dipropionate therapy in asthma patients.

STUDY OBJECTIVES: The fractional concentration of exhaled nitric oxide (FENO) is a marker of asthmatic airway inflammation. We determined the dose response and the reproducibility of the FENO fall following inhaled beclomethasone dipropionate (iBDP) therapy in nonsteroid-treated asthmatic patients. STUDY DESIGN: Study A: For four 1-week periods (period 1 to period 4), the following regimens were administered in sequential order to 15 nonsteroid-treated asthmatic patients: period 1, placebo; period 2, 100 microg/d of iBDP; period 3, 400 microg/D of iBDP; and period 4, 800 microg/d of iBDP. Spirometry, FENO, and provocative concentration of methacholine resulting in a 20% fall in FEV(1) (PC(20)) were measured at each of five visits (visit 1 to visit 5). Study B: During four periods, 12 nonsteroid-treated asthmatic patients received placebo treatment for 7 days (period 1), 200 microg/d of iBDP for 14 days (period 2), washout on placebo treatment until the FENO was within 15% of baseline (period 3), and 200 microg/d of iBDP for 14 days (period 4). RESULTS: Study A: Mean FEV(1) rose progressively from 3.10 L (visit 1) to 3.41 L (visit 5; p = 0.001). All iBDP doses caused a significant FEV(1) rise compared to placebo treatment, but with no significant separation of doses using FEV(1). FENO geometric mean (95% confidence limits) fell progressively from 103.5 parts per billion (ppb) (78.5 to 136.7) to 37.4 ppb (29.1 to 48.0) from visit 1 to visit 5 (p = 0.001). All doses of iBDP resulted in a significant change in FENO from placebo treatment, but with significant separation of only the 100-microg and 800-microg doses by FENO. Geometric mean (95% confidence limits) PC(20) rose progressively from 0.01 mg/mL (0.00 to 0.19) to 0.48 mg/mL (0.01 to 8.1) from visit 1 to visit 5 (p = 0.002). All doses of iBDP resulted in a significant change in PC(20) from baseline or placebo treatment, but with no significant separation of active iBDP doses using PC(20). Study B: FENO fell from 111.56 ppb (80.3 to 155.1) to 66.3 ppb (49.2 to 89.5; p < 0.001) from period 1 to period 2, and from 110.2 ppb (79.3 to 153.1) to 61.7 ppb (42.9 to 88.8; p < 0.001) from period 3 to period 4. There were no significant differences between FENO in period 1 and period 3 (p = 0.83) or between period 2 and period 4 (p = 0.220). CONCLUSIONS: FENO was superior to FEV(1) and PC(20) in separating doses of iBDP. The fall in FENO after two identical administrations of iBDP separated by placebo washout was highly reproducible.

Administration, Inhalation↗

PubMed2000

Hypoxia depresses nitric oxide output in the human nasal airways.

OBJECTIVES: The role of oxygen in the nasal air on nasal nitric oxide (NO) output was studied in 13 adult volunteers. METHODS: Nasal NO was measured while air containing oxygen (0%-100% in nitrogen) was aspirated through the nasal airway before and after the topical application of xylometazoline. RESULTS: The mean nasal NO output of the untreated nose was 507.8 +/- 161.9 nL/min (mean +/- SD) when 21% oxygen was aspirated through the nasal cavities in series and remained unaltered by 100% O2 (P = .79). Below 10% oxygen the reduction in nasal NO output correlated positively and significantly with the decrease in oxygen concentration (r2 = 0.14). NO output was 245.2 +/- 153.4 nL/min at 0% oxygen, a significant decline from 21% oxygen (P < .0001). Nasal vasoconstriction induced by xylometazoline and alterations in the blood oxygen content by a maximal breath-holding or breathing 100% oxygen did not alter nasal NO in hypoxia (P = .41). CONCLUSIONS: Nasal NO output is markedly depressed in hypoxia and is oxygen dependent at concentrations of less than 10%. Approximately 50% of nasally generated NO is produced from oxygen in nasal air or regulated by it.

Administration, Topical↗

PubMed2000

A new ventilator for monitoring lung mechanics in small animals.

Researchers investigating the genetic component of various disease states rely increasingly on murine models. We have developed a ventilator to simplify respiratory research in small animals down to murine size. The new ventilator provides constant-flow inflation and tidal volume delivery independent of respiratory parameter changes. The inclusion of end-inspiratory and end-expiratory pauses simplifies the measurement of airway resistance and compliance and allows the detection of dynamic hyperinflation (auto-positive end-expiratory pressure). After bench testing, we performed intravenous methacholine challenge on two strains of mice (A/J and C57bl/bj) known to differ in their responses by using the new ventilator. Dynamic hyperinflation and a decrease in compliance developed during methacholine challenge whenever respiratory rates of 60-120 breaths/min were employed. In contrast, if dynamic hyperinflation was prevented by lengthening expiratory time, (respiratory rate = 20 breaths/min), static compliance remained constant. More importantly, the coefficient of variation of the results decreased when lung volume shifts were prevented. In conclusion, airway challenge studies have greater precision when dynamic hyperinflation is prevented.

Air Pressure↗

PubMed2000

Airway nitric oxide diffusion in asthma: Role in pulmonary function and bronchial responsiveness.

If the nitric oxide (NO) diffusing capacity of the airways (DNO) is the quantity of NO diffusing per unit time into exhaled gas (q) divided by the difference between the concentration of NO in the airway wall (Cw) and lumen, then DNO and C(w) can be estimated from the relationship between exhaled NO concentration and expiratory flow. In 10 normal subjects and 25 asthmatic patients before and after treatment with inhaled beclomethasone, DNO averaged 6.8 +/- 1.2, 25.5 +/- 3.8, and 22.3 +/- 2.7 nl/s/ppb x 10(-3), respectively; C(w) averaged 149 +/- 31.9, 255.3 +/- 46.4, and 108.3 +/- 14.3 ppb, respectively; and DNOC(w) (the maximal from diffusion) averaged 1,020 +/- 157.5, 6,512 +/- 866, and 2,416 +/- 208.5 nl/s x 10(-3), respectively. DNO and DNOC(w) in the asthmatic subjects before and after steroids were greater than in normal subjects (p < 0.0001), but C(w) was not different. Within asthmatic subjects, steroids caused C(w) and DNOC(w) to fall (p < 0.0001), but DNO was unchanged. DNOC(w) after steroids, presumably reflecting maximal diffusion of constitutive NO, was positively correlated with methacholine PC(20) and FEV(1)/FVC before or after steroids. The increased DNO measured in asthmatic patients may reflect upregulation of nonadrenergic, noncholinergic, NO-producing nerves in airways in compensation for decreased sensitivity of airway smooth muscle to the relaxant effects of endogenous NO.

Administration, Inhalation↗

PubMed2000

Unsuspected pseudophysiologic emphysema in chronic persistent asthma.

The current literature emphasizes the role of airway remodeling in chronic persistent asthma and its putative effect on causing fixed expiratory airflow limitation. We studied 18 adults with chronic persistent asthma; 12 men, six women, age 59 +/- 15 yr (mean +/- SD) with fixed expiratory airflow obstruction. We measured lung elastic recoil and examined the mechanism of expiratory airflow limitation. Diaphragmatic strength was also measured in six asthmatics, using both sniff and partially occluded airway technique. All 18 asthmatics had markedly abnormal maximal expiratory flow-volume curves at both high and low lung volumes. Hyperinflation was present at residual volume (RV), FRC, and TLC in all subjects. Diffusing capacity was normal or elevated and lung computed tomography (CT) was normal in all 18 asthmatic subjects. There was a significant loss of lung elastic recoil in three of four asthmatics age 30 to 49, all five age 51 to 60 yr, and seven of nine age 61 to 82 yr. Maximal expiratory airflow limitation in only four elderly asthmatics and only at low lung volumes was due completely to loss of lung elastic recoil. In the others, we estimate the reduction in lung elastic recoil was responsible for 35% reduction in maximal expiratory airflow at 80% of TLC, and 55% at 70% of TLC. Despite hyperinflation, transdiaphragmatic pressures and strength were normal. The mechanisms responsible for loss of lung elastic recoil remain elusive. The high incidence of loss of lung elastic recoil in chronic persistent asthma was unexpected, and its contribution to abnormal lung function needs to be emphasized.

Adult↗

PubMed2000

Unilateral nasal nitric oxide measurement after nasal surgery.

This study was designed to validate and standardize a method for unilateral nasal nitric oxide (NO) measurement. Fourteen healthy volunteers and 11 patients who had undergone unilateral medial maxillectomy were enrolled. Nasal NO was measured unilaterally by means of a dual pump system, and bilateral nasal NO was measured by aspirating air through the nasal airway in series. The median unilateral NO output was 195 nL/min on the surgical side and 291 nL/min on the contralateral, surgically untreated side (p = .006). The NO output was not significantly different between nostrils in the control group (p = .82). With the bilateral technique, there was no significant difference between the surgery group and the healthy-subjects group (p = .72). The unilateral nasal NO technique is sensitive in determining unilateral differences in nasal NO production. The NO outputs from the nostrils were similar in normal subjects regardless of the nasal cycle, but were significantly lower on the operated side in the unilateral nasal surgery group.

Adult↗

PubMed1999

Nitric oxide accumulation in the nonventilated nasal cavity.

BACKGROUND: Nasal nitric oxide is present in high concentrations in the upper airway relative to the lower respiratory tract. OBJECTIVE: To explore the rate of nitric oxide accumulation in the nonventilated nasal cavity. METHODS: In 9 healthy subjects previously trained to close the soft palate, steady-state plateau nitric oxide levels were recorded while air was aspirated through the nasal airway in series at a constant flow rate. Nitric oxide was then allowed to accumulate in the nasal cavity by occluding both nares and keeping the velum closed. After varying occlusion times, peak nitric oxide levels and a second plateau were ascertained. RESULTS: While the subjects aspirated air at a constant flow, there was a slow rise to a first nitric oxide plateau. On opening to the analyzer after the accumulation period, the peak nitric oxide level was several times higher than the initial plateau (range, 2810-19008 ppb) and then slowly returned to previous plateau levels. There was no significant difference between initial and second plateau nitric oxide levels for any period. The accumulated nitric oxide peak increased in direct proportion to the accumulation time (P<.001). CONCLUSIONS: Nitric oxide concentrations accumulate in the nonventilated nasal cavity in proportion to the time of nonventilation. Peak nasal nitric oxide values after accumulation are similar to published sinus nitric oxide measurements obtained by direct puncture. These results suggest an important alternative source of nitric oxide in humans.

Adult↗

PubMed1999

Lung function after bilateral lower lobe lung volume reduction surgery for alpha1-antitrypsin emphysema.

This study explores the mechanism(s) of airflow limitation following lung volume reduction surgery (LVRS) in patients with emphysema due to homozygous alpha1-antitrypsin (AT) deficiency. Bilateral targeted lower lobe stapled LVRS using video thoracoscopy was performed in six patients (five males) aged 61+/-9 yrs (mean+/-SD) with alpha1-AT emphysema. Two patients received only a 6-month follow-up. However, four patients, at 22, 24, 27 and 36 months post-LVRS, noted relief from dyspnoea and increased walk tolerance. At 27+/-6 months (mean+/-SD) post-LVRS, their forced expiratory volume in one second improved only from 30+/-2% of the predicted value (mean+/-SEM) before surgery to 33+/-1% pred after surgery. Yet, total lung capacity (TLC) decreased from 151+/-13 to 127+/-10% pred; diffusing capacity increased from 35+/-9 to 59+/-9% pred; and vital capacity increased from 68+/-10 to 88+/-5% pred. In three patients, static lung elastic recoil at TLC increased from 1.1+/-0.15 to 1.2+/-0.10 kPa. Using flow/pressure curves, the mechanism for expiratory airflow limitation pre-LVRS and the improvement noted post-LVRS could be primarily accounted for by the initial loss and subsequent increase in lung elastic recoil. Bilateral lung volume reduction surgery provides modest physiologic improvement for 2-3 yrs in patients with alpha1-antitrypsin emphysema due to increases in lung elastic recoil.

Dyspnea↗

PubMed1999

Sensitization to cat without direct exposure to cats.

BACKGROUND: Allergy to pets, particularly cats, is one of the most important determinants of asthma and asthma-like symptoms in many parts of the world. Cat allergen is found in homes and public places without cats. OBJECTIVE: The purpose of the study is to investigate the prevalence of sensitization to cat on the island of Tristan da Cunha where cats have been eliminated since 1974. METHODS: A cross-sectional survey was conducted in 1993 on all residents on the island including allergy skin testing. Dust samples were collected from 20 homes on the island for measurement of house dust mite and cat allergens. RESULTS: Positive skin test reaction to cat was present in 57 (20.1%) of all islanders and in six (12.8%) of those born in or after 1975, 1 year after cats had been exterminated. Five of these six residents were born within 5 years of extermination of cats; two of these had attended school outside the island. A low level of cat allergen (Fel d 1) was found in only one out of 20 homes even though house dust mite allergens (Der p 1 or Der f 1) were found in all homes. CONCLUSION: Sensitization to cat allergen occurs on the island of Tristan da Cunha where there is no direct exposure to cats. This is due either to the persistence of the allergen after the removal of the animal or to the allergen being brought in on visitors' clothing.

Animals↗

PubMed1999

Aerodynamic influences on nasal nitric oxide output measurements.

Nitric oxide (NO) concentration in aspirated nasal air is flow-dependent. Nasal NO outputs calculated from steady-state plateaux at flows < 1 l/min are substantially smaller than those at flows > 2 l/min. This study aimed to determine the differences in NO output as calculated from the NO concentration plateaux in aspirated nasal air, resulting from different aspiration flows. Nasal NO was determined by chemiluminescent analysis of air obtained from the nasal passages in series during velopharyngeal closure in 8 healthy adults (flows: 0.2-3.7 l/min) and 5 with symptomatic allergic rhinitis (flows: 0.2-3.7 l/min). Mean NO output in the healthy subjects was stable at approximately 315 nl/l/min at flows of 0.2-0.7 l/min, and increased to a second steady output level of approximately 400 nl/l/min (+28%, p < 0.0001) at more physiological flow rates of 2.7 l/min and higher. The symptomatic subjects had substantially higher NO output at all flows (p < 0.001) (709.3 nl/min at 3.7 l/min) than the non-allergic subjects. The flow dependency of the nasal NO output may be explained by failure at low flows for the air stream to penetrate the peripheral parts of the complex nasal passages, and by the presence of a laminar flow regime in which a marginal lamina would tend to insulate the main stream from the mucosa. Thus, previously reported NO outputs obtained at low flows may underestimate nasal NO output compared to output at higher and more physiological transnasal airflow rates, thus affecting interpretation of results.

Adult↗

PubMed1999

Exhaled nitric oxide after beta2-agonist inhalation and spirometry in asthma.

Exhaled nitric oxide (ENO) is used increasingly as a surrogate marker of airway inflammation in research protocols that may incorporate standard efficacy measures, such as spirometry before and after bronchodilator, which could affect ENO measurements. In seven healthy volunteers and 11 mild asthmatic subjects, we measured ENO before and serially for 1 h after spirometry. On two additional days in the subjects with asthma, we reexamined the effect of spirometry as before, followed by the serial measurement of ENO for 1 h after two puffs of salbutamol (100 microgram/puff) by metered-dose inhaler or matching placebo. As early as 1 min after spirometry, ENO fell by 13% and 10% in the normal and asthmatic subjects, respectively. In both groups, ENO returned to baseline over 1 h. In the asthmatic subjects, salbutamol caused a significant mean increase of the order of 10 parts per billion in ENO (p < 0.001) for 1 h as compared with placebo inhaler. We conclude that spirometry and beta2-agonist may perturb ENO values and recommend that studies control for these factors.

Administration, Inhalation↗

PubMed1999

Does snoring contribute to presbycusis?

It is well known that hearing acuity decreases with age. The precise mechanism responsible for this phenomenon, called presbycusis, is unknown. One hypothesis advanced to explain this loss of acuity implicates chronic exposure to snoring noise. Consequently, the purpose of this study was to investigate whether snoring is associated with hearing loss. We examined 219 patients (63 women and 156 men) referred to our sleep disorders center. All of the patients underwent nocturnal polysomnography with measurements of snoring, as well as standard audiometry (i.e., measurement of hearing thresholds at 250 Hz, 500 Hz, 1 kHz, 2 kHz, 3 kHz, 4 kHz, 6 kHz, and 8 kHz). Snoring was quantified by measuring three parameters: snoring index (SI = number of snores/h of sleep), average nocturnal sound intensity (dBav), and maximum nocturnal sound intensity (dBmax). We used simple correlation analysis to investigate the relationship between snoring and hearing thresholds; multiple linear regression analysis to determine individual contributions of age, sex, and snoring to the variability in hearing thresholds; and comparison tests to determine whether mild snorers had less hearing impairment than severe snorers. None of these statistical tests demonstrated that snoring was a significant determinant of hearing. We conclude that snoring is not associated with hearing loss and is therefore unlikely to account for presbycusis.

Adolescent↗

PubMed1999

Exhaled nitric oxide as a noninvasive assessment of chronic cough.

Exhaled nitric oxide (ENO) has been suggested as a marker of airway inflammation. This study aimed to evaluate the role of ENO in the investigation of chronic cough. We measured ENO in 38 adult patients reporting chronic cough, in 23 healthy control subjects, and in 44 asthmatics. In addition to the regular investigation, ENO was measured by a chemiluminescent analyzer using the restricted breath technique. In the chronic cough group, 30 were considered as nonasthmatic, whereas asthma was diagnosed in eight by a positive methacholine challenge. ENO values were significantly higher in patients with chronic cough attributable to asthma as compared with those with chronic cough not attributable to asthma and to healthy volunteers (75.0 ppb; 16.7 ppb; and 28.3 ppb, respectively). The sensitivity and specificity of ENO for detecting asthma, using 30 ppb as the ENO cutoff point, were 75 and 87%, respectively. The positive and negative predictive values were 60 and 93%, and the positive and negative likelihood ratios were 5.8 and 0.3, respectively. We conclude that ENO may have a role in the evaluation of chronic cough. In this group of patients, low ENO suggested little likelihood of asthma. The patients with chronic cough not attributable to asthma showed a low ENO value as compared with healthy volunteers and asthmatics.

Adult↗

PubMed1999

Nasal nitric oxide does not control basal nasal patency or acute congestion following allergen challenge in allergic rhinitis.

Nasal nitric oxide (NO), a powerful vasodilator, could control the filling of nasal capacitance vessels, thus determining nasal patency and mediating the acute congestion accompanying allergen challenge. We examined the effect of topical N-nitro-L-arginine-methyl-ester (L-NAME; 100 to 200 mg), an NO synthase inhibitor, on nasal NO and on nasal patency assessed by acoustic rhinometry in 7 subjects with nasal allergy, and in 4 subjects we examined the effects of nasal allergen challenge on nasal NO before and after a short course of nasal steroid. After L-NAME, nasal NO fell to 42.1%+/-15.7% of baseline (p < .0001) with no significant change in minimal cross-sectional area. After allergen challenge, acute congestion was associated with a significant fall in nasal NO, which returned to baseline by 4 hours, when the congestion resolved. Repeat challenge after 2 weeks of nasal corticosteroid yielded similar findings. A role for NO in modulating vascular tone was not supported by the present study.

Acute Disease↗

PubMed1999

Lung function 4 years after lung volume reduction surgery for emphysema.

STUDY OBJECTIVES: Current data for patients > 2 years after lung volume reduction surgery (LVRS) for emphysema is limited. This prospective study evaluates pre-LVRS baseline data and provides long-term results in 26 patients. INTERVENTION: Bilateral targeted upper lobe stapled LVRS using video thoracoscopy was performed in 26 symptomatic patients (18 men) aged 67 +/- 6 years (mean +/- SD) with severe and heterogenous distribution of emphysema on lung CT. Lung function studies were measured before and up to 4 years after LVRS unless death intervened. RESULTS: No patients were lost to follow-up. Baseline FEV(1) was 0.7 +/- 0.2 L, 29 +/- 10% predicted; FVC, 2.1 +/- 0.6 L, 58 +/- 14% predicted (mean +/- SD); maximum oxygen consumption, 5.7 +/- 3.8 mL/min/kg (normal, > 18 mL/min/kg); dyspneic class > or = 3 (able to walk < or = 100 yards) and oxygen dependence part- or full-time in 18 patients. Following LVRS, mortality due to respiratory failure at 1, 2, 3, and 4 years was 4%, 19%, 31%, and 46%, respectively. At 1, 2, 3, and 4 years after LVRS, an increase above baseline for FEV(1) > 200 mL and/or FVC > 400 mL was noted in 73%, 46%, 35%, and 27% of patients, respectively; a decrease in dyspnea grade > or = 1 in 88%, 69%, 46%, and 27% of patients, respectively; and elimination of oxygen dependence in 78%, 50%, 33%, and 22% of patients, respectively. The mechanism for expiratory airflow improvement was accounted for by the increase in both lung elastic recoil and small airway intraluminal caliber and reduction in hyperinflation. Only FVC and vital capacity (VC) of all preoperative lung function studies could identify the 9 patients with significant physiologic improvement at > 3 years after LVRS, respectively, from 10 patients who responded < or = 2 years and died within 4 years (p < 0.01). CONCLUSIONS: Bilateral LVRS provides clinical and physiologic improvement for > 3 years in 9 of 26 patients with emphysema primarily due to both increased lung elastic recoil and small airway caliber and decreased hyperinflation. The 9 patients had VC and FVC greater at baseline (p < 0.01) when compared to 10 short-term responders who died < 4 years after LVRS.

Aged↗