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Biomedical subjects

N Maranetra

Publications and source records attributed to N Maranetra.

At least 19 recordsLinked to original sources
PubMed1998

Beta 2-agonists administered by a dry powder inhaler can be used in acute asthma.

Patients with acute asthma attending the emergency room were included in a double-blind, double-dummy and parallel group study to investigate whether a dry powder inhaler (Turbuhaler) can be used in acute asthma. If so, the aim was to establish the potency relationship between a beta 2-agonist (salbutamol) administered by the dry powder inhaler and the pressurized metered-dose inhaler (pMDI). Eighty-six patients with a mean age of 38 years and forced expiratory volume in 1 s (FEV1) of 37% of predicted normal value were randomized at Siriraj Hospital in Bangkok to either Turbuhaler (50 micrograms dose -1) or pMDI (100 micrograms dose -1) with spacer (Volumatic). Doses of 100 + 300 + 300 + 300 micrograms salbutamol were given at 0, 15, 30 and 45 min via Turbuhaler and repeated at 90, 105, 120 and 135 min (total dose 2000 micrograms). The same inhalation schedule with identical number of doses was used for the pMDI with spacer but in double doses (total 4000 micrograms), assuming a dose-potency ratio of salbutamol administered via Turbuhaler compared with the pMDI of 2:1. At 85 min after the first dose, 60 mg prednisolone was given orally. FEV1 was measured 10 min after each dosing. Peak inspiratory flow (PIF) through Turbuhaler was measured on each dosing occasion. Plasma (P)-salbutamol, serum (S)-potassium concentrations, pulse rate, blood pressure and adverse events were recorded. No statistically significant differences were observed in the increase in FEV1 between the groups: 55 min (165 min) after the first dose, the increase was 0.47 l and 47% (0.64 l and 63%) in the Turbuhaler group, and 0.46 l and 42% (0.68 l and 65%) in the pMDI group. Mean PIF though Turbuhaler was 49 l min -1 (range 26-68) at first inhalation and increased to 60 l min -1 (range 38-86). There was no correlation between the initial PIF through Turbuhaler and the initial FEV1 response. P-salbutamol and S-potassium values correlated well. A larger decrease in S-potassium was noticed after 75 min in the pMDI group (0.38 mmol l -1) compared with the Turbuhaler group (0.23 mmol l -1) (P = 0.02). In conclusion, the use of a dry powder inhaler, Turbuhaler, was investigated in the emergency room treatment of acute asthma, and was as effective as a pMDI with spacer. Half the dose of salbutamol administered via Turbuhaler was as effective as the full dose given via a pMDI with spacer.

Acute Disease↗
PubMed1998

Diagnostic value of bronchoalveolar lavage and postbronchoscopic sputum cytology in peripheral lung cancer.

The objective of this study was to evaluate the value of bronchoalveolar lavage (BAL) and postbronchoscopic sputum cytology in diagnosing peripheral lung cancer. We performed a prospective study in 55 patients with lesions on chest radiographs who were suspected of having lung cancer and had non-endoscopically visible lesions on fiberoptic bronchoscopy. The sequence of procedures in all cases was BAL and transbronchial forceps biopsy. The final diagnosis of these patients were primary lung cancer in 30 patients, metatastic lung cancer in five and benign diseases in 20. In the primary lung cancer group, BAL was positive for malignant cells in 14 of the 30 patients (46.7%). In seven (50%) of these patients, the cell type diagnosed by BAL agreed with the final diagnosis. The diagnostic yield of BAL was influenced by the size and segmental location of the lesion. Bronchoalveolar lavage provided a higher diagnostic yield (46.7%) than transbronchial biopsy (16.7%). In five patients with metastatic lung cancer and 20 patients with benign disease, BAL gave negative results in all. Postbronchoscopic sputum cytology was positive in only two of the 26 patients (7.7%) from whom samples could be obtained. Bronchoalveolar lavage cytology proved to be a valuable diagnostic tool in detecting peripheral, primary lung cancer. Postbronchoscopic sputum cytology provided no significant additional information.

Biopsy↗
PubMed1996

The efficacy of doxycycline as a pleural sclerosing agent in malignant pleural effusion: a prospective study.

To determine the efficacy of doxycycline in producing pleuroedesis in patients with malignant pleural effusion (MPE), 31 documented cases of MPE, aged 19-82 years were prospectively studied. Pleural sclerosis was done with 500 mg of doxycycline. Response regarding respiratory symptoms and pleural fluid accumulation were evaluated monthly. At one month, 27 patients were evaluable (4 dropped out). All responded and required no therapeutic thoracentesis. At 3 months, 13 patients dropped out, only 14 patients were evaluable. It revealed that 13 out of 14 patients (92%) responded. Only one patient failed and required therapeutic thoracentesis. Five and two patients came for assessment at 6 and 12 months, respectively. They still benefited from doxycycline pleurodesis. Side effects including low grade fever in 30% of patients, moderate to severe pain in 60% and troublesome cough with hemoptysis in one patient (3%) were noted. Doxycycline is an effective agent in controlling MPE. It was successful in every patient at 1 month and in 92% at 3 months. At 6 and 12 months quite a few patients survived for evaluation. However, they still benefited from doxycycline pleurodesis. Side effects were tolerable.

Adult↗
PubMed1990

Respiratory centre sensitivity and exercise tolerance in healthy Thais.

To determine the range of normal values of respiratory centre sensitivity and exercise tolerance in Thais, 69 healthy subjects, 18 to 72 years of age, participated in a series of tests, i.e. ventilatory drive, ventilatory response, musculo-ventilation transfer and the two-minute walking test with rating of the breathing sensation on a visual analogue scale. Our results showed higher end-tidal Pco2 and tidal volume response to CO2 and less exercise tolerance in the elderly than in the young. Only in young males was the ventilatory response to CO2 higher than in females. No attempt has yet been made to explain the lower ventilatory response in Thais as compared with Americans. Apparently, the defective respiratory apparatus, viz. increased airways resistance and not the blunting of respiratory centre sensitivity, contributes principally to relative hypoventilation and exercise limitation in the elderly. The compensation, with high tidal volume response to CO2, seems ineffective in maintaining normo-ventilation.

Adolescent↗
PubMed1990

Oxygen desaturation during fibreoptic bronchoscopy.

One hundred consecutive patients, who underwent bronchoscopic examination for diagnostic purposes, were studied with regard to various aspects of possible SaO2 deterioration. Relevant findings are as follows: (1) The pulse oximeter is as good as the conventional blood gas analyser for quantitating SaO2; (2) oxygen desaturation in the range of 1 to 25 per cent (median 5, mean 5.6 +/- 4) occurred in approximately 97 per cent of the bronchoscopy examinees; recuperation time of SaO2 was 1 to 34 minutes (median 6, mean 8.2 +/- 6.5); (3) the factor aggravating desaturation included the examination of patients in the sitting position; the fact that bronchial washing was connected with greater SaO2 deterioration in the non-hypoxaemic group of patients needs further investigation with regard to its role in the mechanism of oxygen desaturation; (4) the amount of fluid instilled intra-tracheally, bronchial biopsy and duration of the procedure were not related to the decline in SaO2. Based on the results of the present study, the authors suggest that all procedures ought to be performed on patients undergoing examination in the supine position, and that the patients should be supplemented with low-flow oxygen.

Adolescent↗
PubMed1990

Ventilatory control, exercise tolerance and respiratory dysfunction in Thai COPD patients.

This study was designed to investigate a group of Thai COPD patients for their respiratory centre sensitivity while breathing room-air and during CO2 rebreathing, and tests to determine exercise tolerance and degrees of respiratory dysfunction. Results in 56 patients as compared with 45 age-matched healthy subjects disclosed comparable data between both subject groups, with the single exception that one-third (35.7%) of the patients experienced stronger ventilatory drive while breathing room-air and a lower musculo-ventilation transfer index during room-air breathing as well as CO2 rebreathing. According to the base-line dyspnoea index, the majority of Thai COPD patients in this study suffered from a very severe respiratory dysfunction, which correlated well with results of their basic physiologic tests.

Aged↗
PubMed1990

Clinico-physiological status of Thai COPD patients.

We examined the relationships between certain clinical and physiological data from 56 patients with chronic obstructive pulmonary disease, and have formulated 15 relevant equations from which various respiratory indices can be estimated. Multiple linear regressions thus obtained evidently suggest that airway resistance and ventilatory drive are the main factors in the control of breathing among Thai COPD subjects; the exercise tolerance test showed some correlation with airflow obstruction and with respiratory muscle strength. Clinical implementation of certain findings has been outlined.

Aged↗
PubMed1988

HLA antigen profiles in Thai tuberculosis patients.

HLA antigens were studied in 35 Thai patients suffering from active pulmonary tuberculosis. An increase in the frequency of HLA-Bw46 and -DR4 and a decrease in the frequency of HLA-B12 were found when compared with the matched controls. These findings suggest that the pathogenetic role of HLA-B12 is to confer resistance and that HLA-Bw46 and -DR4 are associated with susceptibility. In addition it provided further information on HLA antigen profiles in pulmonary tuberculosis patients in another ethnic group (viz. Thais). Conclusions regarding genetic control over therapeutic efficacy must await further study.

Adolescent↗
PubMed1982

Hypercapnic ventilatory control in patients with chronic airflow obstruction: a follow-up study.

A four year follow-up study of ventilatory control has been performed in 50 patients with chronic airflow obstruction. Hypercapnia was induced by rebreathing, and both the ventilation and the mouth pressures produced during transient airway conclusion during inspiration were obtained. Both the chemoreceptor sensitivity to hypercapnia (delta P/delta PCO2) and the ventilatory response (delta V/delta PCO2) measured during the initial study were shown to be unrelated to prognosis when the outcome of these patients was determined four years later. A relationship between initial hypercapnia and survival was found. Twenty of the patients were restudied. No significant change occurred in the chemosensitivity to hypercapnia over the four year period. In the initial study and the follow-up study hypercapnia was also found to be associated with a reduced chemoreceptor sensitivity. Although both chemosensitivity to hypercapnia and survival were found to be separately related to arterial CO2 tension, there was no direct relationship between them. These results suggest that any possible influence of chemosensitivity on survival is likely to be overshadowed by other factors.

Adult↗
PubMed1976

Action of tilidine hydrochloride and morphine hydrochloride on ventilatory control in normal subjects.

The action of tilidine hydrochloride and morphine hydrochloride on the ventilatory response to inhaled carbon dioxide has been assessed in 10 normal volunteers. In doses of 50 mg and 100 mg given intravenously, tilidine hydrochloride induced less respiratory depression than 10 mg of morphine given intravenously. Side effects were not different or troublesome with either drug. Depending on its relative pain-relieving property, tilidine hydrochloride may have advantages over morphine as an analgesic.

Adult↗