Frequency dependence of compliance in the evaluation of patients with unexplained respiratory symptoms

Frequency dependence of compliance (FDC) reflects non-homogeneous ventilatory distribution and, in the presence of a normal measured airway resistance, suggests peripheral airways dysfunction. This study evaluated peripheral airway function and bronchial reactivity in irritant exposed or non-exposed individuals with normal routine pulmonary function tests (PFTs) who had persistent unexplained lower respiratory symptoms. Twenty-two patients were identified with persistent respiratory symptoms and with normal chest X-ray and PFTs. Twenty were non-smokers; two had stopped smoking more than 10 years before evaluation. Twelve patients had been exposed to irritants in their workplaces or at home. Non-specific bronchial hyper-reactivity (nsBHR) and FDC, pre- and post-bronchodilator, were measured in all patients. Studies were repeated in 6/12 irritant-exposed subjects after exposure removal and inhaled corticosteroid treatment. Whereas 12/22 patients had nsBHR, all 22 subjects demonstrated FDC [dynamic lung compliance/static lung compliance Cdyn,1 / Cst,1 at respiratory frequency 60 min(-1) (f60), mean 46%, range 27-67%]. After bronchodilator administration, a 15% improvement Cdyn,1 was observed most consistently at f60 (mean% improvement 26%, 95% CI 14-38%) and in subjects without nsBHR. However, Cdyn,1 at f60 did not return to normal after inhaled bronchodilator. Irritant-exposed and unexposed individuals appeared similar in results of testing for FDC and nsBHR. FDC and its response to bronchodilators provide objective physiological measures of an airway abnormality which may provide a basis for clinical symptoms in patients with normal routine pulmonary function studies. The presence of persistently abnormal FDC after bronchodilator (BD) and on follow up studies may reflect chronic inflammatory and/or structural changes in the airways in addition to bronchoconstriction.     

Distal airway function in symptomatic subjects with normal spirometry following World Trade Center dust exposure

RATIONALE: Following collapse of the World Trade Center (WTC), individuals reported new-onset respiratory symptoms. Despite symptoms, spirometry often revealed normal airway function. However, bronchial wall thickening and air trapping were seen radiographically in some subjects. We hypothesized that symptomatic individuals following exposure to WTC dust may have functional abnormalities in distal airways not detectable with routine spirometry. METHODS: One hundred seventy-four subjects with respiratory symptoms and normal spirometry results were evaluated. Impedance oscillometry (IOS) was performed to determine resistance at 5 Hz, 5 to 20 Hz, and reactance area. Forty-three subjects were also tested for frequency dependence of compliance (FDC). Testing was repeated after bronchodilation. RESULTS: Predominant symptoms included cough (67%) and dyspnea (65%). Despite normal spirometry results, mean resistance at 5 Hz, 5 to 20 Hz, and reactance area were elevated (4.36 +/- 0.12 cm H(2)O/L/s, 0.86 +/- 0.05 cm H(2)O/L/s, and 6.12 +/- 0.50 cm H(2)O/L, respectively) [mean +/- SE]. Resistance and reactance normalized after bronchodilation. FDC was present in 37 of 43 individuals with improvement after bronchodilation. CONCLUSIONS: Symptomatic individuals with presumed WTC dust/fume exposure and normal spirometry results displayed airway dysfunction based on the following: (1) elevated airway resistance and frequency dependence of resistance determined by IOS; (2) heterogeneity of distal airway function demonstrated by elevated reactance area on oscillometry and FDC; and (3) reversibility of these functional abnormalities to or toward normal following administration of a bronchodilator. Since spirometry results were normal in all subjects, these abnormalities likely reflect dysfunction in airways more distal to those evaluated by spirometry. Examination of distal airway function when spirometry results are normal may be important in the evaluation of subjects exposed to occupational and environmental hazards.     

河北省SARS患者出院20个月后肺功能调查分析

目的 分析严重急性呼吸综合征（SARS）患者出院后肺功能变化，了解SARS患者预后。方法 调查了203例SARS患者康复20个月后健康状况，对遗留干咳、活动性气短者行肺功能检查，合并骨关节症状者进行相应部位磁共振（MRI）检查；同时回顾其住院期间的临床资料。结果 33例出院者遗留干咳、活动性气短等症状，其中32例同时合并有骨关节症状，住院期间均接受了抗感染、抗病毒及适量。肾上腺糖皮质激素治疗。肺功能检测发现部分出院者FEV1％、FEV1／FVC％、V50％预计值和D1CO％预计值降低，表现为轻度肺功能异常。合并骨坏死者FEV。／FVC显著低于未合并骨坏死者，而发病年龄和高热天数显著增高（P〈0．05）；两者弥散功能指标（DLCO％）差异无统计学意义。结论 SARS患者出院20个月后仍有部分患者存在轻度肺功能异常，以弥散障碍为主，少数存在小气道功能障碍和肺通气障碍；病情较重者易合并骨坏死，而肺弥散功能障碍恢复较好。     

Pulmonary function in newborns after repair of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is associated with pulmonary hypoplasia that limits survival, but the nature and extent of pulmonary dysfunction in neonates with CDH have not been studied. We performed pulmonary function tests (PFTs) in eight intubated infants who survived neonatal repair of CDH (wt, 3.33 ± 0.15 kg; age, 20.1 ± 2.7 d; mean ± S.E.M.). PFTs obtained from six full-term infants (wt, 3.56 ± 0.10 kg; age, 25.0 ± 3.3 d) with no respiratory illness served as controls. The deflation flow-volume curve technique produced maximum expiratory flow-volume (MEFV) curves, giving reproducible measurements of forced vital capacity (FVC) and maximal expiratory flow at 25% of FVC (MEF₂₅). Respiratory system compliance (Crs) and resistance (Rrs) were obtained with a modified passive mechanics technique. In seven of eight infants PFTs were repeated after nebulized bronchodilator (0.1% isoetharine). In neonates surviving CDH repair, as compared to those with normal lung function, FVC was significantly reduced (20.78 ± 3.32 vs. 39.83 ± 3.30 mL · kg^?1, P < 0.05). MEF₂₅ was also markedly reduced (8.41 ± 1.46 vs. 32.32 ± 4.35 mL · kg^?1 · s^?1, P < 0.05), indicating lower airway obstruction. After administration of nebulized bronchodilator, PFTs showed significant increases from control values in both FVC (15.9%) and MEF₂₅ (200%) without changes in Crs and Rrs. These findings indicate that neonates with CDH have restrictive lung defects, reflecting hypoplasia. After surgical repair and mechanical ventilation airway reactivity develops, primarily in smaller airways, and this may complicate the postoperative course. Pediatr Pulmonol. 1991 ; 11 :49-55.     

Spirometry and impulse oscillometry (IOS) for detection of respiratory abnormalities in metropolitan firefighters

Background and objective: As firefighters are at increased risk of adverse health effects, periodic examination of their respiratory health is important. The objective of this study was to establish whether the use of impulse oscillometry (IOS) reveals respiratory abnormalities in metropolitan firefighters that go undetected during routine respiratory health screening by spirometry and assessment of respiratory symptoms. Methods: This was a cross‐sectional analysis of spirometry, IOS and questionnaire data from 488 male firefighters. Abnormal spirometry was defined as FEV₁, FEV₁/FVC and/or FEF₅₀ below the lower limit of normal. Abnormal IOS was defined as resistance at 5 Hz (R5), frequency dependence of resistance (ΔR5‐R20) and/or reactance area (AX) above the upper limit of normal. Respiratory symptoms, smoking history, exposures and medical history were assessed. Data were analysed using logistic and linear regression models. Results: The mean age of the firefighters was 43.8 (SD 8.4) years. There were 123 (25%) former smokers and 50 (10%) current smokers. Abnormal spirometry was detected in 12%, abnormal IOS in 9% and respiratory symptoms in 20% of firefighters. Current smoking was associated with all IOS parameters (OR for R5 = 3.1, OR for ΔR5‐R20 = 7.7, OR for AX = 4.3), and with FEF₅₀ (OR = 9.1), chronic productive cough (OR = 4.0) and breathlessness (OR = 5.4) (P < 0.05 for all). Exposure during firefighting duties was associated with chronic productive cough (OR = 2.6), but not with spirometry or IOS parameters. Interaction terms in the linear regression models indicated associations between smoking and ΔR5‐R20, and also between smoking and AX, in the lowest and second lowest quartiles of spirometry parameters. Conclusions: Application of IOS for the assessment of respiratory health in firefighters identified airways dysfunction in some individuals, even when spirometry values were within the normal range and there were no respiratory symptoms.     

Functional predictors of exertional dyspnea, 6-min walking distance and HRCT fibrosis score in idiopathic pulmonary fibrosis

BACKGROUND: Exertional dyspnea and exercise incapacity are the most prominent and disabling symptoms and the main contributors to health-related quality of life in patients with idiopathic pulmonary fibrosis (IPF). OBJECTIVES: There are no comprehensive studies on pulmonary function tests (PFTs), dyspnea, exercise capacity and radiographic scores in IPF. We therefore sought to investigate the functional variables that can predict dyspnea, exercise capacity and disease extent in IPF. METHODS: Thirty-four patients with IPF according to the ATS/ERS criteria underwent PFTs, Medical Research Council (MRC) dyspnea scoring, 6-min walking distance (6-MWD) and radiographic evaluation of fibrosis (HRCT score). RESULTS: The 6-MWD (% pred.) was more impaired than PFTs. Residual volume (RV) showed the best correlation with the extent of fibrosis (r = -0.67, p = 0.0001) and, together with the alveolar-arterial gradient for O(2) [DeltaP(A - a)O(2)], was an independent predictor of disease extent (R(2) = 0.44). PFTs showed significant though weak correlations with MRC score and 6-MWD. According to the regression analysis, DL(CO) and the HRCT fibrosis score were independent predictors of dyspnea, though they explained only 28% of the overall variance. FEV(1) and DeltaP(A - a)O(2) were independent predictors of 6-MWD (R(2) = 0.31). CONCLUSIONS: PFTs and lung volumes in particular are closely related to the HRCT score, a measure of the extent of IPF. The correlation of dyspnea score and 6-MWD to PFTs is limited, due to the complexity of mechanisms leading to exercise limitation in IPF. Therefore dyspnea and exercise performance are largely independent indices and should be followed together with PFTs and HRCT score in order to better assess the status and progress of IPF patients.     

Impact of respiratory symptoms and pulmonary function on quality of life of long-term survivors of non-small cell lung cancer

PURPOSE: To describe respiratory symptoms and pulmonary function among long-term survivors of non-small cell lung cancer (NSCLC), and their relationship to quality of life (QOL). METHODS: Cross-sectional survey of disease-free, 5-year minimum survivors of NSCLC (n = 142; 54% women; average age, 71 years); the majority (74%) had received a lobectomy. Analysis included frequency of self-reported respiratory symptoms (cough, phlegm, wheezing, breathlessness) as measured by the American Thoracic Society questionnaire, pulmonary function findings from hand-held spirometry, and QOL (Short Form-36). RESULTS: Two thirds of survivors reported at least one respiratory symptom (mean, 1.3; SD, 1.2): 25% cough, 28% phlegm, 31% wheezing, and 39% dyspnea. Twenty-one percent reported that they spent most of the day in bed in the past 12 months because of respiratory symptoms. Average FEV(1) percentage predicted was 68% (SD, 23); 21% had < 50% predicted FEV(1). Based on spirometry results, 36% had a moderate/severe obstructive and/or restrictive ventilatory disorder. Survivors exposed to second-hand smoke (28%) were more than three times as likely to report respiratory symptoms. Respiratory symptom burden contributed to diminished QOL in several domains. CONCLUSIONS: The majority of these survivors experienced respiratory symptoms, and more than one third reported dyspnea, including one of five patients with seriously diminished pulmonary function. Symptom burden, rather than ventilatory impairment, contributed to diminished QOL. Further study is needed to determine the patterns and effective management of posttreatment respiratory symptoms on survivors of lung cancer.     

The relationship between pulmonary function and dyspnea in obstructive lung disease

Increased importance is now being placed on evaluating dyspnea in patients with obstructive lung disease (OLD). We measured breathlessness at rest, using a Borg scale dyspnea index (BSDI) before and after bronchodilator albuterol [salbutamol] 200 micrograms) in 93 patients with OLD drawn from a larger population undergoing routine spirometry. The median BSDI declined from 3 to 1 before and after bronchodilator, suggesting improvement in dyspnea. However, there was no correlation between initial or postbronchodilator spirometry and BSDI. The change in FEV1 similarly did not correlate with the change in BSDI (r = 0.05). A large bronchodilator response was usually associated with improvement in dyspnea, but the converse was not observed. Thus, of ten patients with an improvement in BSDI of more than two categories, six had a change in FEV1 of 0.1 L or less after bronchodilator. Analyzing a subgroup of 65 dyspneic patients with an initial BSDI of 2 or more revealed the following response groups: those with either a bronchodilator or dyspnea response alone, both together, or neither. Twenty-eight patients (43 percent) responded both subjectively and objectively. Eleven (17 percent) had a bronchodilator response only, 17 (26 percent) had a dyspnea response only, while nine (14 percent) had neither measurable response. We conclude that dyspnea is poorly correlated with results of routine spirometry in patients with OLD. The use of dyspnea ratings may yield information about bronchodilator responsiveness not appreciated by spirometry alone.     

Prospective evaluation of amiodarone pulmonary toxicity

Reports of pulmonary infiltrates in patients taking amiodarone, initiated the study of 69 patients for pulmonary toxicity using serial chest roentgenograms (CXRs), pulmonary function tests (PFTs), and symptoms before and during therapy. Mean PFTs did not significantly change from their baseline normal values, but 10 percent of patients had a greater than or equal to 15 percent fall in total lung capacity, and 28 percent a greater than or equal to 15 percent fall in diffusion capacity (DCO) following treatment. Initial abnormalities in pulmonary function or CXR were predictive of risk of developing pulmonary toxicity. Degree of exposure to amiodarone (dose plus duration) correlated only weakly with development of pulmonary toxicity, which could occur in patients taking relatively small doses of the drug. Pulmonary complications of amiodarone are common, in most cases reversible, and often confused with congestive heart failure or pneumonia. Patients should be evaluated before treatment by assessing symptoms, CXRs, and DCO. Patients with initial abnormalities in these parameters, particularly both CXR and DCO abnormalities, should be considered for alternative therapy.     

Quality of Pulmonary Function Tests in Participants with Down Syndrome

IntroductionPeople with Down syndrome (DS) have high respiratory morbidity, evaluating their respiratory health with standardized, objective tests is desirable. Thus, the objective of this study was to evaluate the technical quality of Pulmonary Function Tests (PFTs) to determine which ones are most suitable for this population.MethodsParticipants included children, teenagers and adults with DS, 5 years of age or older (n = 302). The technical quality of the impulse oscillometry system (IOS), forced spirometry, lung-diffusing capacity for carbon monoxide (DL_CO), and 6-min walk test (6MWT) were analyzed by age group. Capnography and pulse oximetry were included in the study. Technical quality was determined on the basis of current international PFTs standards.ResultsFifty-one percent of participants were males. A total of 184 participants (71%) who completed the IOS fulfilled the quality criteria, while 210 (70%) completed the 6MWT. Performance on forced spirometry and DL_CO was poor. All pulse oximetries and 96% percent heart rates obtained had good quality, but exhaled carbon dioxide (PetCO₂) and respiratory rate (RR) showed deficient repeatability.ConclusionsIOS appears to be the most reliable instrument for evaluating lung mechanics in individuals with DS.     

Ipratropium in patients with COPD receiving cholinesterase inhibitors

Three patients with chronic obstructive lung disease (COPD) and myasthenia gravis whose pulmonary symptoms were worsened by therapy with cholinesterase inhibitors were improved by inhaled ipratropium bromide. Two had increases in FEV1 (19 percent, 35 percent) and specific conductance (106 percent, 81 percent) and reductions in dyspnea. The third had no change in airflow with ipratropium, but improved due to decreased bronchial secretions which had limited the use of cholinesterase inhibitors. In contrast, beta agonist bronchodilators had no effect in any of these patients. This experience suggests that ipratropium may be the bronchodilator drug of choice in patients with obstructive lung disease aggravated by cholinesterase inhibitors.     

Radiological and functional assessment of pulmonary involvement in the rheumatoid arthritis patients

The aim was to evaluate the findings of high resolution computed tomography (HRCT) and pulmonary function tests (PFT) in the rheumatoid arthritis (RA) patients with and without pulmonary symptoms and to determine their role in prediction of respiratory system involvement. Among 54 consecutive RA patients, 22 (41%) were symptomatic and 32 (59%) were asymptomatic after detailed respiratory examination. Abnormal findings in PFTs were present in 10 (45%) symptomatic and 15 (47%) asymptomatic patients. PFT results were similar in both groups. A total of 18 (82%) symptomatic and 16 (50%) asymptomatic patients had abnormalities in HRCT scans. About 16 (80%) of 20 patients with normal HRCT scans had no pulmonary symptoms at all and we noted a significant correlation (P < 0.05). HRCT was more useful mean than PFTs in evaluation of pulmonary involvement in the RA patients; however, no correlation was present between various respiratory symptoms and abnormal findings both in PFTs and HRCT scans.     

Nitrogen dioxide pneumonitis in ice hockey players

Karlson-Stiber C, Höjer J, Sjöholm Å, Bluhm G, Salmonson H (Swedish Poison Information Centre, the Department of Internal Medicine, Söder Hospital, and the Department of Environmental Health and Infectious Disease Control, Karolinska Hospital, Stockholm; and the Department of Internal Medicine, Löwenströmska Hospital, Upplands Väsby; Sweden). Nitrogen dioxide poisoning with toxic pneumonitis in ice hockey players (Case report). J Intern Med 1996; 239: 451–6.
Exposure to the toxic gases carbon monoxide and nitrogen dioxide (NO₂) in indoor ice arenas occasionally occurs and may result in severe symptoms. The gases are produced by ice resurfacing machines operating on hydrocarbons, and in certain conditions toxic levels accumulate. The damage to lung tissues caused by NO₂ may not be evident until after a latency time of ½–2 days. The role of corticosteroids in the treatment is controversial, but there are clinical experiences as well as experimental data supporting their use.
We report two cases of toxic pneumonitis, with delayed onset, due to NO₂ exposure during an ice hockey game in an indoor arena. Signs and symptoms were cough, dyspnoea, haemoptysis, hypoxaemia and reduced peak expiratory flow. Chest radiographs showed parenchymatous infiltrative lesions and alveolar consolidation. Both patients were treated with high doses of corticosteroids by inhalation and orally or intravenously. Their condition rapidly improved and pulmonary function was restored.     

Resting Physiological Correlates of Reduced Exercise Capacity in Smokers with Mild Airway Obstruction

Smokers with minor spirometric abnormalities can experience persistent activity-related dyspnea and exercise intolerance. Additional resting tests can expose heterogeneous physiological abnormalities, but their relevance and association with clinical outcomes remain uncertain. Subjects included sixty-two smokers (≥20 pack-years), with cough and/or dyspnea and minor airway obstruction [forced expiratory volume in one-second (FEV₁) ≥80% predicted and >5th percentile lower limit of normal (LLN) (i.e., z-score >?1.64) using the 2012-Global Lung Function Initiative equations]. They underwent spirometry, plethysmography, oscillometry, single-breath nitrogen washout, and symptom-limited incremental cycle exercise tests. Thirty-two age-matched nonsmoking controls were also studied. Thirty-three (53%) of smokers had chronic obstructive pulmonary disease by LLN criteria. In smokers [n = 62; age 65 ± 11 years; smoking history 43 ± 19 pack-years; post-bronchodilator FEV₁ z-score ?0.60 ± 0.72 and FEV₁/FVC z-score ?1.56 ± 0.87 (mean ± SD)] versus controls, peak oxygen uptake (?VO₂) was 21 ± 7 vs. 32 ± 9 ml/kg/min, and dyspnea/?VO₂ slopes were elevated (both p < 0.0001). Smokers had evidence of peripheral airway dysfunction and maldistribution of ventilation when compared to controls. In smokers versus controls: lung diffusing capacity for carbon monoxide (D_LCO) was 85 ± 22 vs. 105 ± 17% predicted, and residual volume (RV)/total lung capacity (TLC) was 36 ± 8 vs. 31 ± 6% (both p < 0.01). The strongest correlates of peak ?VO₂ were D_LCO% predicted (r = 0.487, p < 0.0005) and RV/TLC% (r = ?0.389, p = 0.002). D_LCO% predicted was also the strongest correlate of dyspnea/?VO₂ slope (r = ?0.352, p = 0.005). In smokers with mild airway obstruction, associations between resting tests of mechanics and pulmonary gas exchange and exercise performance parameters were weak, albeit consistent. Among these, DLCO showed the strongest association with important outcomes such as dyspnea and exercise intolerance measured during standardized incremental exercise tests.     

Lung function in infants with wheezing and gastroesophageal reflux

Eighty-four otherwise healthy infants with daily wheezing underwent infant pulmonary function tests (IPFTs) and 24-h esophageal pH probe studies. Fifty-four (64%) infants had positive pH probe studies, and 30 infants had negative pH probe studies. Many infants in both groups had evidence of peripheral airflow obstruction at tidal breathing and on forced expiration as measured by thoracoabdominal compression. In infants with gastroesophageal reflux (GER), only 9 of 54 (16.6%) responded to bronchodilator therapy compared to 20 of 30 (66.6%) in the group with negative pH probe studies (P < 0.0005). In infants with positive pH studies, family history of asthma (n = 16) correlated well with positive response to bronchodilators (P < 0.0005), and all infants exposed to maternal smoking (n = 11) had no response to bronchodilators. Forty-four percent of infants with a positive pH probe had no gastrointestinal symptoms suggestive of GER. In infants with a negative pH probe, family history of asthma (n = 24) correlated well with positive response to bronchodilators (P < 0.0005), and exposure to maternal smoking (n = 8) correlated well with no response to bronchodilator therapy (P < 0.0005). We conclude that silent GER is common in infants with persistent wheezing. Furthermore, infants with GER are less likely to respond to bronchodilator therapy, and exposure to maternal smoking and family history of asthma may be significant independent factors.     

An international collaborative pathologic study of surgical lung biopsies from mustard gas-exposed patients

BACKGROUND: Recent studies have shown strong evidence that bronchiolitis obliterans is the major long-term sequelae of exposure to sulfur mustard (SM). This study is the first to examine the histopathologic spectrum of changes in a large number of surgical lung biopsies from patients exposed to SM. METHOD: Fifteen patients with chronic respiratory disease from mustard gas exposure were divided into severe (6 cases) and mild exposure (9 cases). All had surgical (open or thoracoscopic) lung biopsy, pulmonary function tests (PFTs) and chest high-resolution computed tomography scan (HRCT). RESULT: The mean age of the cases was 43.8+/-9.6 (range 33-65). All patients had dyspnea and cough as the two main complaints. Only one patient was a smoker. Thirteen patients had normal PFTs, while one had obstruction and one had mild restriction. Six (66.6%) patients in the mild exposure and 3 (50%) in the severe exposure group showed evidence of more than 25% air trapping on chest HRCT. Among the mild group, 3 had features of constrictive bronchiolitis and another had features suggestive of this (bronchiolectasis and mucus stasis). The next most common finding was a mild-to-moderate chronic cellular bronchiolitis (3 patients). Two among the 6 in the severe group showed constrictive bronchiolitis and one showed features suggestive of constrictive bronchiolitis. CONCLUSION: We conclude that about half of patients had diagnostic constrictive bronchiolitis, or bronchiolectasis and mucus stasis consistent with more proximal luminal compromise. The fact that there were no differences between the low- and high-dose groups suggests that effects of SM are not solely dependent on the severity of exposure. The results also indicate that the diagnosis of chronic lung disease due to SM may be difficult. Surgical lung biopsy may be helpful in difficult cases, as constrictive (obliterative) bronchiolitis can be present in symptomatic patients with normal PFTs and chest HRCT.     

Pulmonary function assessment in the early phase of patients with smoke inhalation injury from fire

Objectives

Fire smoke contains toxic gases and numerous chemical compounds produced by incomplete combustion, and may cause injury to the airways. Increased airway reactivity, as well as a decrease in lung function, has been reported as a sequela of smoke inhalation injury. This study was undertaken to assess lung functions in the early phase of patients with smoke inhalation damage from fires.

Methods

A total of 15 patients with fire smoke inhalation (fire smoke group) and 15 subjects with chronic cough but no previous history of lung disease (chronic cough group) were enrolled. For diagnosis of inhalation injury, we performed bronchoscopy, high-resolution computed tomography (HRCT), as well as arterial carboxyhemoglobin (COHb) at admission. Clinical characteristics, pulmonary function tests (PFTs) and mannitol bronchial provocation tests (BPTs) were analyzed and compared between the two groups.

Results

In fire smoke group, initial COHb levels and the PaO₂/FiO₂ ratio were (14.8±18.49)% and 425.7±123.68, respectively. Of seven patients performing HRCT, 4 (57.1%) showed the CT findings compatible with lung involvement of inhalation injury. Post bronchodilator value of the percent of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁) were (76.0±24.27)% and (79.8±27.82)%, respectively. Pre-and post- bronchodilator forced expiratory flow between 25% and 75% of the FVC (FEF_25-75) and the percent predicted FEF_25-75 were 2.41±1.47 vs. 2.65±1.45 L (P=0.045), and (68.7±37.29)% vs. (76.4±36.70)% (P=0.031), respectively. Two patients (13.3%) had positive bronchodilator response (BDR). In fire smoke and chronic cough group, all the subjects showed mannitol BPTs within normal limits.

Conclusions

Fire smoke inhalation leads to mild obstructive small airway disease pattern of pulmonary function in the early phase of patients with fire smoke damage. Further studies, however, need to be followed to identify the relationship between airway narrowing to inhaled mannitol and smoke inhalation injury.     

An 11-year-old male patient with refractory asthma and heartburn

Achalasia is characterized by obstruction of the distal esophagus and subsequent dilation of the proximal esophagus, and is considered to be a rare disorder in children. Patients commonly present with gastrointestinal (GI) symptoms such as dysphagia; however, pulmonary symptoms may also occur. Rare pulmonary symptoms due to achalasia are dyspnea and wheeze due to tracheal compression. The authors describe an 11-year-old boy who was referred to a pediatric respiratory clinic for asthma that was not responsive to inhaled medications. The child presented with a one-year history of dyspnea on exertion, cough and wheeze. He also complained of chronic dyspepsia. The presence of GI symptoms, in addition to abnormalities on chest radiograph and spirometry, suggested the presence of achalasia. The diagnosis was confirmed and the patient subsequently underwent surgical myotomy that relieved his GI and pulmonary symptoms, and normalized spirometry. The present article is an illustrative case report to remind pediatricians to consider other diagnoses when a patient does not respond to asthma medications.     

Prevalence of Gastroesophageal Reflux in Elderly Patients in a Primary Care Setting

Despite the aging of our population, there remains a paucity of information about gastroesophageal reflux (GER) in the elderly. To assess the prevalence and characteristics of GER within this patient population, questionnaires evaluating symptoms associated with GER were administered to 313 consecutive patients 62 yr old or older from a primary care setting. Fourteen percent of these patients reported having at least weekly heartburn. Ambulatory 24-h esophageal pH monitoring was accomplished in 54 of the 313 patients surveyed. Twenty percent (11/54) of this subgroup exhibited increased acid contact time (pH less than 4 for more than 6% of the monitoring period). Twenty-two percent (12/54) complained of heartburn, yet only six individuals (11%) exhibited both symptomatic and objective indications of acid reflux. Surprisingly, 31% (17/54) of the patients studied exhibited significant alkalinity within the distal esophagus (pH greater than 8 for greater than 1.5% of the monitoring period). Whereas 29% of these patients (5/17) reported heartburn, 40% of those reporting heartburn (2/5) had acid GER as well as excessive alkalinity. In contrast to patients with acid GER--none of whom reported pulmonary symptoms--24% (4/17) of these patients with esophageal alkalinity reported wheezing, nocturnal cough, or paroxysmal nocturnal dyspnea. Of the four patients with significant distal esophageal exposure to both acid and alkali, two reported heartburn and a third reported dysphagia. In addition to the somewhat higher prevalence of acid reflux than anticipated, a surprisingly high prevalence of esophageal alkalinity was observed.     

Impulse Oscillometry and Respiratory Symptoms in World Trade Center Responders, 6 Years Post-9/11

This study evaluated whether impulse oscillometry (IOS) testing revealed signs of respiratory disease in New York State (NYS) World Trade Center (WTC) responders in comparison with unexposed NYS employees. It also compared self-reported respiratory symptoms between the two groups, 6 years post-9/11. For this evaluation participants completed a self-administered questionnaire regarding respiratory symptoms. IOS testing included measures of resistance and reactance to assess for peripheral versus central airway effects. Two hundred forty-eight subjects (99 exposed and 149 unexposed) were included in the final analysis. Since September 11, 2001, NYS responders were more likely to report new or worsening cough in the absence of a respiratory infection, cough consistent with chronic bronchitis, current respiratory symptoms, or lower respiratory symptoms in the last 12 months. Significant associations were found between IOS indices and gender, smoking history, and obesity. When comparing exposed and unexposed participants, there were no significant differences in the geometric means of the IOS indices. Responders who used a respirator with canister demonstrated significantly lower respiratory resistance at 5 and 20 Hz (R5 and R20). While this study has provided no evidence of an association between WTC exposure and peripheral airways disease in this cohort of responders, results do suggest that use of a respirator with canister may be protective for central airways in responders exposed to dust and smoke. This emphasizes the importance of stressing proper respirator use in planning responses to future disasters. Our control data also provide useful reference values for future IOS research.