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1.
Eur Respir J ; 38(4): 770-3, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21436351

ABSTRACT

The safety of talc pleurodesis is under dispute following reports of talc-induced acute respiratory distress syndrome (ARDS) and death. We investigated the safety of large-particle talc for thoracoscopic pleurodesis to prevent recurrence of primary spontaneous pneumothorax (PSP). 418 patients with recurrent PSP were enrolled between 2002 and 2008 in nine centres in Europe and South Africa. The main exclusion criteria were infection, heart disease and coagulation disorders. Serious adverse events (ARDS, death or other) were recorded up to 30 days after the procedure. Oxygen saturation, supplemental oxygen use and temperature were recorded daily at baseline and after thoracoscopic pleurodesis (2 g graded talc). During the 30-day observation period following talc poudrage, no ARDS (95% CI 0.0-0.9%), intensive care unit admission or death were recorded. Seven patients presented with minor complications (1.7%, 95% CI 0.7-3.4%). After pleurodesis, mean body temperature increased by 0.41Ā°C (95% CI 0.33-0.48Ā°C; p<0.001) at day 1 and returned to baseline value at day 5. Pleural drains were removed after day 4 in 80% of patients. Serious adverse events, including ARDS or death, did not occur in this large, multicentre cohort. Thoracoscopic talc poudrage using larger particle talc to prevent recurrence of PSPS can be considered safe.


Subject(s)
Pleurodesis/methods , Pneumothorax/therapy , Respiratory Distress Syndrome/prevention & control , Talc/administration & dosage , Thoracoscopy/methods , Adolescent , Adult , Aged , Aged, 80 and over , Drainage/methods , Female , Fever/chemically induced , Humans , Male , Middle Aged , Oxygen Inhalation Therapy/methods , Particle Size , Pleurodesis/adverse effects , Pneumothorax/surgery , Prospective Studies , Respiratory Distress Syndrome/chemically induced , Secondary Prevention , Talc/adverse effects , Talc/chemistry , Thoracoscopy/adverse effects , Young Adult
2.
Respir Med ; 101(1): 139-45, 2007 Jan.
Article in English | MEDLINE | ID: mdl-16709452

ABSTRACT

Central airway obstruction can cause severe respiratory insufficiency leading to mechanical ventilation (MV) or artificial airway (AA) dependency. Interventional bronchoscopic procedures have been reported to be of help in weaning patients with malignant airway stenoses from mechanical ventilation, whereas their use in benign disease is only anecdotal. The objectives of this study are to evaluate early, intermediate and long-term outcome of interventional bronchoscopy and stent placement in the treatment of MV/AA dependency due to benign airway obstruction. In a retrospective cohort analysis for the period 1999-2004, we evaluated 15 consecutive ICU patients with documented benign central airway obstruction, who were referred for bronchoscopic management of their condition after multiple failed attempts at weaning from MV or decannulation of the AA. Indications for bronchoscopic treatment were surgery refusal, medical or surgical inoperability, or absence of alternative treatment options. Malacia, post-intubation stenosis and goiter were the main causes of airway obstruction and MV/AA dependency. All patients were treated by means of rigid bronchoscopy, dilatation procedures and stent insertion. All but one patient (93.3%) were successfully and permanently extubated/decanulated immediately after the bronchoscopy. Minor complications occurred in 6 patients (40%) leading to a second intervention. All complications could be managed endoscopically and long-term follow up was uneventful. Interventional bronchoscopy with stent insertion can allow successful withdrawal from MV/AA and can offer longstanding airway patency in selected ventilator- or tracheostomy-dependant individuals with benign airway stenoses,when surgery in not feasable or contra-indicated.


Subject(s)
Airway Obstruction/therapy , Catheterization , Respiration, Artificial , Stents , Tracheostomy , Aged , Airway Obstruction/etiology , Bronchoscopy , Device Removal , Female , Follow-Up Studies , Goiter/complications , Humans , Intensive Care Units , Intubation, Intratracheal , Laryngostenosis/complications , Male , Middle Aged , Retrospective Studies , Tracheal Stenosis/complications , Treatment Outcome , Ventilator Weaning
5.
Int J Radiat Oncol Biol Phys ; 40(4): 967-76, 1998 Mar 01.
Article in English | MEDLINE | ID: mdl-9531383

ABSTRACT

PURPOSE: To analyze setup errors and the feasibility of their on-line correction using electronic portal imaging in the irradiation of lung tumors. METHODS AND MATERIALS: Sixteen patients with lung cancer were irradiated through opposed anteroposterior fields. Localization images of anteroposterior fields were recorded with an electronic portal imaging device (EPID). Using an in-house developed algorithm for on-line comparison of portal images setup errors were measured and a correction of table position was performed with a remote couch control prior to treatment. In addition, residual errors were measured on the EPID verification image. Global and individual mean and standard deviation of setup errors were calculated and compared. The feasibility of the procedure was assessed measuring intra- and interobserver variability, influence of organ movement, reproducibility of error measurement, the extra time fraction needed for measuring and adjusting and the fraction of dose needed for imaging. RESULTS: In two setups the procedure could not be finished normally due to problems inherent to the procedure. The reproducibility, intraobserver variability, and influence of organ movements were each described by a distribution with a mean value less than or equal to 1 mm and a standard deviation (SD) of less than 1.5 mm. The interobserver variability showed to be a little bit larger (mean: 0.3 mm, SD: 1.7 mm). The mean time to perform the irradiation of the anteroposterior field was 4 +/- 1 min. The mean time for the measurement and correction procedure approximated 2.5 min. The mean extra time fraction was 65 +/- 24% (1 SD) with more than half of this coming from the error measurement. The dose needed for generation of EPID images was 5.9 +/- 1.4% of total treatment dose. The mean and SD of setup errors were, respectively, 0.1 and 4.5 mm for longitudinal and -2.0 and 5.7 mm for transversal errors. Of 196 measured translational errors 120 (61%) exceeded the adjustment criteria. For individual patients systematic and random setup errors can be as high as, respectively, 15.8 and 7.5 mm. Mean residual error and SD were for longitudinal direction 0.08 and 1.2 mm and for transversal direction -0.9 and 1.0 mm (pooled data). For individuals, the mean residual errors were smaller than 1 mm, with a typical SD per patient of less than 2 mm. CONCLUSION: Setup errors in thoracic radiation therapy are clinically important. On-line correction can be performed accurately with an objective measurement tool, although this prolongs the irradiation procedure for one field with 65%.


Subject(s)
Algorithms , Carcinoma, Non-Small-Cell Lung/radiotherapy , Lung Neoplasms/radiotherapy , Radiotherapy Planning, Computer-Assisted/methods , Feasibility Studies , Humans , Observer Variation , Reproducibility of Results
6.
Chest ; 110(6): 1615-8, 1996 Dec.
Article in English | MEDLINE | ID: mdl-8989088

ABSTRACT

In two patients with a goiter and respiratory symptoms occurring only in the recumbent posture, flow-volume loops (FVLs) were performed in various body postures: while sitting upright, supine, and left and right lateral decubitus. In both patients, flow rates, upper airway obstruction indices, and FVL morphologic features with patients in recumbent postures indicated the appearance of upper airway flow limitation with patients in the recumbent posture as compared with the upright posture. In the one patient who underwent thyroid surgery, these posture-related changes disappeared. We conclude that in patients with a goiter (or any extrinsic mass near to the upper airway), the comparison of FVLs performed in various body positions may help to clarify the origin of posture-related respiratory symptoms.


Subject(s)
Airway Obstruction/etiology , Goiter/complications , Pulmonary Ventilation , Adult , Aged , Airway Obstruction/physiopathology , Female , Humans , Male , Posture
7.
Chest ; 97(2): 373-6, 1990 Feb.
Article in English | MEDLINE | ID: mdl-2298062

ABSTRACT

We investigated the bronchodilating effect of intravenous MgSO4 in acute severe bronchial asthma. Infusion of MgSO4 caused a significant improvement in FEV1 (0.94 +/- 0.39L to 1.3 +/- 0.44 L) and an improvement in clinical signs and symptoms in ten out of 12 administrations. The bronchodilating effect of MgSO4, however, was significantly less than that of subsequent albuterol inhalation (FEV1 improvement from 1.13 +/- 0.41 L to 1.72 +/- 0.49 L). These findings confirm that intravenous MgSO4 may be used as an adjunct to classic beta 2-agonist therapy in cases of severe acute asthma; its exact place in the treatment of asthma remains to be determined in large-scale studies.


Subject(s)
Asthma/drug therapy , Magnesium Sulfate/therapeutic use , Administration, Inhalation , Albuterol/administration & dosage , Albuterol/therapeutic use , Bronchodilator Agents , Female , Humans , Infusions, Intravenous , Magnesium Sulfate/administration & dosage , Male , Middle Aged
8.
Chest ; 102(4): 1099-103, 1992 Oct.
Article in English | MEDLINE | ID: mdl-1395751

ABSTRACT

Although the hypokalemic effect of inhaled beta 2-adrenergic agonists has been well documented, little is known as to their effect on plasma magnesium. We therefore examined in ten healthy young volunteers the effect of the inhalation of 2 mg of nebulized fenoterol on plasma potassium (Kpl), plasma magnesium (Mgpl), and intraerythrocytic magnesium (MgIE) levels, as well as on plasma insulin and C peptide concentrations, measured before and serially up to 110 min after fenoterol inhalation. In all subjects, fenoterol inhalation caused a reversible reduction in Kpl (range, 0.2 to 1.1 mEq/L), which was progressive, reaching a statistically significant nadir 30 to 60 min following fenoterol inhalation (largest dip in Kpl, 0.55 +/- 0.29 mEq/L; p < 0.05). The nadir in Kpl levels was preceded by a peak in plasma insulin levels in all subjects. No significant changes in Mgpl or MgIE were observed in any of the subjects. We conclude that fenoterol inhaled at a dosage used in clinical practice significantly reduces Kpl but not Mgpl nor MgIE levels in healthy subjects, indicating a lower sensitivity of Mg++ ions to beta 2-adrenergic stimulation than K+ ions. Beta 2-adrenergic-induced insulin secretion probably contributes to the hypokalemic effect of inhaled fenoterol.


Subject(s)
Fenoterol/pharmacology , Administration, Inhalation , Adult , C-Peptide/analysis , Erythrocytes/metabolism , Female , Fenoterol/administration & dosage , Humans , Insulin/blood , Magnesium/blood , Male , Potassium/blood
9.
Chest ; 115(2): 532-5, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10027456

ABSTRACT

STUDY OBJECTIVES: A frequent complication of the widely used Dumon silicone stent is its tendency to migrate when used in tracheal stenosis. We compared the clinical efficacy and complications (including migration) of the Dumon stent with a screw-thread stent, a device with an increased stent-to-wall contact surface and, theoretically, less tendency to migrate. DESIGN: Retrospective case analysis. SETTING: Academic hospital. MATERIALS AND METHODS: Forty-six patients with tracheal stenoses (23 benign and 23 malignant) requiring the placement of 50 stents (29 Dumon and 21 screw-thread) were studied. In 26 patients Dumon stents were used, and in 20 patients screw-thread stents were used. Both patient groups had comparable clinical and stenosis-related characteristics. RESULTS: Stent insertion and follow-up were uneventful in both the Dumon and the screw-thread insertions, respectively: 62% vs 67% (not significant). There were seven migrations in the Dumon group, compared to only one migration in the screw-thread group, respectively: 24% vs 5%. This difference did not reach statistical significance (p = 0.1). All of the migrations occurred in the benign stenosis group, and none occurred in the malignant-stenosis group, respectively: 8 of 23 vs 0 of 23, p = 0.004. Within the benign-stenosis group, the Dumon stent had a significantly increased risk for migration when compared to the screw-thread stent, respectively: 7 of 13 vs 1 of 11, p = 0.033. CONCLUSIONS: The screw-thread stent and the Dumon stent are equally effective in the management of tracheal stenosis. There is a general trend toward a decreased migration rate, and a significantly lower risk for migration in patients with benign tracheal stenosis. The (less expensive) screw-thread stent may represent an attractive alternative in the management of tracheal stenosis in general, and may be preferable to the Dumon stent in treating benign tracheal stenosis.


Subject(s)
Stents , Tracheal Stenosis/therapy , Aged , Female , Foreign-Body Migration , Humans , Male , Middle Aged , Prosthesis Design , Retrospective Studies
10.
Chest ; 113(2): 528-31, 1998 Feb.
Article in English | MEDLINE | ID: mdl-9498977

ABSTRACT

Intractable pain is the most invalidating symptom in patients suffering from chronic pancreatitis. Anatomical interruption of the major afferent pain nerves is indicated in severe refractory cases. Among the various techniques and sites of interruption, thoracoscopic splanchnicectomy has emerged as an efficient alternative for the more aggressive open surgical splanchnicectomy, and for the (solely temporarily efficacious) transcutaneous neural blocks, which moreover bear some serious complications. Until now, all reports on thoracoscopic splanchnicectomy were typically surgical, using video-assisted thoracoscopic surgery techniques, double-lumen intubation, and so on. In analogy with thoracoscopic upper dorsal T2-T3 sympathicolysis for essential hyperhidrosis, a simplified thoracoscopic splanchnicolysis technique used in 8 patients suffering from either severe refractory chronic pancreatitis pain (7 patients) or postsurgical epigastric pain is described. Pain control was achieved in 5 of the 7 patients with chronic pancreatitis with a short (20+/-8 min) intervention, short hospitalization (2 days), and simple (single-lumen intubation, no chest drains) procedure. Thus, this simplified thoracoscopic splanchnicolysis technique may represent a valid alternative in the often difficult treatment of refractory chronic pancreatitis pain or other upper abdominal pain.


Subject(s)
Endoscopy , Pain, Intractable/surgery , Pancreatitis/physiopathology , Splanchnic Nerves/surgery , Sympathectomy , Thoracoscopy , Abdominal Pain/surgery , Adult , Aged , Chronic Disease , Female , Follow-Up Studies , Hospitalization , Humans , Hyperhidrosis/surgery , Intubation, Intratracheal/instrumentation , Intubation, Intratracheal/methods , Length of Stay , Male , Middle Aged , Minimally Invasive Surgical Procedures , Nerve Block/adverse effects , Nerve Block/methods , Neurons, Afferent/physiology , Pain, Postoperative/surgery , Pulmonary Medicine , Recurrence , Reproducibility of Results , Time Factors , Video Recording
11.
Chest ; 106(2): 520-3, 1994 Aug.
Article in English | MEDLINE | ID: mdl-7774330

ABSTRACT

In many patients with central airway obstruction due to extrinsic compression or malacia, insertion of tracheobronchial stents can provide effective and permanent relief. Of the various types of prostheses described, the silicone Dumon-Artemis stents (Medicore, Brussels, Belgium) are probably the most efficient. The use of an elegant and safe specially designed stent introducer system combined with a special bronchoscope is proposed for insertion by Dumon. This combined stent insertion system, however, is relatively expensive and cumbersome, especially for centers where relatively limited numbers of patients are treated. We propose an alternative, simplified insertion technique of silicone Dumon-Artemis stents, which was proven safe and efficient in our series of patients.


Subject(s)
Bronchial Diseases/therapy , Stents , Tracheal Stenosis/therapy , Aged , Aged, 80 and over , Bronchoscopes , Equipment Design , Female , Humans , Male , Methods , Middle Aged , Silicones
12.
Chest ; 106(1): 262-4, 1994 Jul.
Article in English | MEDLINE | ID: mdl-8020281

ABSTRACT

Thoracoscopic talc poudrage of the entire pleural surface constitutes successful treatment of recurrent pneumothorax in cystic fibrosis (CF); however, subsequent lung transplantation is seriously jeopardized due to the development of extensive pleural adhesions. We describe a 27-year-old patient with CF with recurrent right-sided pneumothorax, refractory to chest tube drainage and to chemical (tetracycline) pleurodesis, who was successfully treated with a localized, apical thoracoscopic talc poudrage, thereby preserving the possibility of subsequent lung transplantation.


Subject(s)
Cystic Fibrosis/complications , Pneumothorax/therapy , Talc/administration & dosage , Thoracoscopy , Adult , Humans , Male , Pleura , Pneumothorax/diagnostic imaging , Pneumothorax/etiology , Radiography , Recurrence
13.
Chest ; 90(3): 462-4, 1986 Sep.
Article in English | MEDLINE | ID: mdl-3743169

ABSTRACT

We report two cases of enlargement of the posterior mediastinal lymph nodes due to sarcoidosis. Bilateral hilar enlargement, pulmonary parenchymal involvement, or extrathoracic manifestations of sarcoidosis were absent. A diagnostic thoracotomy had to be performed in both instances.


Subject(s)
Mediastinal Diseases/diagnosis , Sarcoidosis/diagnosis , Adult , Humans , Lymph Nodes/pathology , Male , Mediastinal Diseases/pathology , Middle Aged , Sarcoidosis/pathology , Tomography, X-Ray Computed
14.
Chest ; 107(6): 1615-20, 1995 Jun.
Article in English | MEDLINE | ID: mdl-7781356

ABSTRACT

Percutaneous needle biopsy (PNB) of localized thoracic disease has become a widespread procedure in many institutions. The development of special small caliber needles has increased the diagnostic yield of PNB partly by increasing the amount of tissue from biopsy, often enabling histologic examination. Nevertheless, in a significant number of patients only cytopathologic examination is possible on the retrieved biopsy fragments, necessitating the presence of a trained cytopathologist in the biopsy room. Furthermore multiple biopsy needle passages often are required, increasing the risk for complications such as pneumothorax. We have evaluated the use of a small-caliber tissue biopsy cutting needle, consistently yielding sufficient biopsy tissue for histologic examination. In 25 pleural and mediastinal lesions, which could be biopsied without passage through aerated lung, there was a 93% sensitivity (7% false-negative results) for neoplasm and a 100% accuracy for benign disease. There were no complications. In 32 patients with lesions of 1 cm in diameter or more surrounded with aerated lung tissue, adequate histologic examination was feasible on every biopsy specimen after only one needle passage. There was an 87% sensitivity of PNB in neoplastic disease (13% false-negatives). In the patients with benign disease, there was a 100% accuracy. There was a 15.6% risk for pneumothorax. In only one patient (3%), however, was chest drainage necessary. One patient (3%) had mild hemoptysis. We conclude that percutaneous biopsy of localized pulmonary, pleural, and mediastinal lesions with a new small-caliber automatic guillotine cutting needle is safe and efficient, enabling recovery of sufficient tissue for histologic examination with a single-pass procedure, thus minimizing the risk for pneumothorax, eliminating the need for a cytopathologist in the biopsy room, and shortening the duration of the procedure.


Subject(s)
Biopsy, Needle/instrumentation , Lung/pathology , Mediastinum/pathology , Needles , Pleura/pathology , Adult , Aged , Aged, 80 and over , Disposable Equipment , Female , Humans , Male , Middle Aged , Radiography, Interventional , Sensitivity and Specificity , Thoracic Neoplasms/diagnosis , Tomography, X-Ray Computed
15.
Chest ; 92(4): 757-8, 1987 Oct.
Article in English | MEDLINE | ID: mdl-3652768

ABSTRACT

Pneumomediastinum following esophageal perforation is a known complication of Eder Puestow dilation for esophageal stenosis. This is the first reported case of esophageal perforation and pneumomediastinum occurring after instrumental self-dilation of a stenotic esophageal lesion. The observed 0.02 percent perforation rate in this patient (compared to the reported 0.3 percent in Eder Puestow "hetero"-dilation) makes the Eder Puestow auto-dilation procedure seem justifiable in a well-trained and well-informed patient.


Subject(s)
Dilatation/adverse effects , Esophageal Perforation/complications , Mediastinal Emphysema/etiology , Aged , Esophageal Perforation/etiology , Esophageal Stenosis/therapy , Humans , Male , Self Care
16.
Chest ; 112(4): 1136-40, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9377935

ABSTRACT

Bronchoscopic balloon dilatation (BBD) using angioplasty balloon catheters has been employed successfully in the treatment of tracheobronchial stenoses in children and has worked with variable success in adults with bronchial stenosis. In adults with tracheal stenosis, BBD only has been reported anecdotally. In this study, experience with BBD using a valvuloplasty balloon catheter in the combined treatment (with Nd-YAG laser photoresection and stenting) of severe benign postintubation tracheal stenoses in three adults is delineated. BBD was particularly successful in establishing tracheal patency when laser photoresection was contraindicated or was too dangerous; BBD allowed easy insertion of tracheal stents and the "opening" of folded silicone stents. BBD is a simple, inexpensive, safe, and efficient adjunct in the combined treatment of severe postintubation rigid tracheal stenosis in selected adults.


Subject(s)
Bronchoscopy , Catheterization , Intubation, Intratracheal/adverse effects , Tracheal Stenosis/therapy , Adult , Aluminum Silicates , Angioplasty, Balloon/instrumentation , Catheterization/instrumentation , Combined Modality Therapy , Equipment Design , Foreign-Body Migration/therapy , Humans , Laser Therapy , Male , Neodymium , Recurrence , Respiration, Artificial/adverse effects , Silicones , Stents , Tracheal Stenosis/etiology , Tracheal Stenosis/surgery , Tracheostomy/adverse effects , Yttrium
17.
Lung Cancer ; 15(3): 281-95, 1996 Nov.
Article in English | MEDLINE | ID: mdl-8959675

ABSTRACT

Patient and tumour characteristics of 23 patients presenting with a second primary lung cancer were analysed and compared with 534 patients with radically resected stage 1 non-small cell lung cancer (NSCLC). None of these characteristics is associated with a higher occurrence rate for second primary lung cancer. Prognosis in the latter patients is significantly worse than after resection of a 'solitary' NSCLC: the median survival time (MST) after resection of the first tumour is 50 months; after diagnosis of the second tumour only 14 months. Surgically retreated patients have a prognosis that is similar to that after resection of a 'solitary' NSCLC. No separate independent prognostic factors responsible for this survival difference could be isolated. Squamous histology and central location are associated with a longer recurrence free survival time. We conclude that the occurrence of a second primary lung cancer can not be predicted based on patient or tumour characteristics and that only surgical retreatment offers a chance of long survival in these patients.


Subject(s)
Carcinoma, Non-Small-Cell Lung/epidemiology , Lung Neoplasms/epidemiology , Neoplasms, Second Primary/epidemiology , Adult , Aged , Aged, 80 and over , Belgium/epidemiology , Biopsy , Carcinoma, Non-Small-Cell Lung/pathology , Carcinoma, Non-Small-Cell Lung/surgery , Female , Follow-Up Studies , Humans , Incidence , Lung Neoplasms/pathology , Lung Neoplasms/surgery , Male , Middle Aged , Neoplasm Staging , Neoplasms, Second Primary/pathology , Neoplasms, Second Primary/surgery , Prognosis , Prospective Studies , Recurrence , Survival Rate
18.
Intensive Care Med ; 16(4): 269-71, 1990.
Article in English | MEDLINE | ID: mdl-2358562

ABSTRACT

We report a patient with amniotic fluid embolism (AFE) in whom the occurrence of late onset, severe pulmonary oedema was due to isolated left ventricular (LV) failure. Following institution of diuretics and inotropic support, the situation promptly improved and follow-up haemodynamic assessment showed complete recovery of LV function. This report indicates that reversible LV failure may occur late after AFE and emphasises the usefulness of pulmonary artery catheterisation for proper assessment and guidance of therapy of pulmonary oedema in AFE.


Subject(s)
Embolism, Amniotic Fluid/complications , Heart Failure/etiology , Puerperal Disorders/complications , Pulmonary Edema/etiology , Adult , Embolism, Amniotic Fluid/diagnosis , Embolism, Amniotic Fluid/physiopathology , Female , Heart Failure/complications , Heart Failure/diagnostic imaging , Hemodynamics , Humans , Pregnancy , Puerperal Disorders/diagnosis , Puerperal Disorders/physiopathology , Pulmonary Edema/physiopathology , Radiography
19.
J Appl Physiol (1985) ; 91(6): 2587-94, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11717223

ABSTRACT

We investigated the differential effect of histamine and methacholine on spirometry and ventilation distribution (where indexes S(cond) and S(acin) represent conductive and acinar ventilation heterogeneity; Verbanck S, Schuermans D, Van Muylem A, Noppen M, Paiva M, and Vincken W. J Appl Physiol 83: 1807-1816, 1997). Thirty normal subjects were challenged with cumulative doses of 6.52 micromol histamine and, on a separate day, with either 6.67 micromol methacholine (equal-dose group; n = 15) or 13.3 micromol methacholine (double-dose group; n = 15). Largest average forced expiratory volume in 1 s (FEV(1)) decreases or S(cond) increases obtained in either group were -9% and +286%, respectively; S(acin) remained unaffected at all times. In the equal-dose group, a smaller FEV(1) decline (P = 0.002) after methacholine was paralleled by a smaller S(cond) increase (P = 0.041) than with histamine. However, in the double-dose group, methacholine maintained a smaller FEV(1) decline (P = 0.009) while inducing a larger S(cond) increase (P = 0.006) than did histamine. The differential action of histamine and methacholine is confined to the conductive airways, where histamine likely causes the greatest overall airway narrowing and methacholine induces the largest parallel heterogeneity in airway narrowing, probably at the level of the large and small conductive airways, respectively. The observed ventilation heterogeneities predict a risk for dissociation between ventilation-perfusion mismatch and spirometry, particularly after methacholine challenge.


Subject(s)
Bronchoconstrictor Agents/pharmacology , Histamine/pharmacology , Methacholine Chloride/pharmacology , Respiration/drug effects , Dose-Response Relationship, Drug , Forced Expiratory Volume/drug effects , Humans , Maximal Midexpiratory Flow Rate/drug effects , Peak Expiratory Flow Rate/drug effects , Spirometry
20.
J Appl Physiol (1985) ; 83(6): 1907-16, 1997 Dec.
Article in English | MEDLINE | ID: mdl-9390962

ABSTRACT

We investigated ventilation inhomogeneity during provocation with inhaled histamine in 20 asymptomatic nonsmoking subjects. We used N2 multiple-breath washout (MBW) to derive parameters Scond and Sacin as a measurement of ventilation inhomogeneity in conductive and acinar zones of the lungs, respectively. A 20% decrease of forced expiratory volume in 1 s (FEV1) was used to distinguish responders from nonresponders. In the responder group, average FEV1 decreased by 26%, whereas Scond increased by 390% with no significant change in Sacin. In the nonresponder group, FEV1 decreased by 11%, whereas Scond increased by 198% with no significant Sacin change. Despite the absence of change in Sacin during provocation, baseline Sacin was significantly larger in the responder vs. the nonresponder group. The main findings of our study are that during provocation large ventilation inhomogeneities occur, that the small airways affected by the provocation process are situated proximal to the acinar zone where the diffusion front stands, and that, in addition to overall decrease in airway caliber, there is inhomogeneous narrowing of parallel airways.


Subject(s)
Bronchial Provocation Tests , Histamine/pharmacology , Respiratory Mechanics/drug effects , Airway Resistance/drug effects , Bronchoconstrictor Agents/pharmacology , Diffusion , Forced Expiratory Volume/drug effects , Gamma Cameras , Humans , Nitrogen , Respiratory Function Tests
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