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Original Articles Indian Pediatrics 2001; 38: 340-348 |
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COMPARATIVE
EFFICIENCY OF COMMERCIAL AND IMPROVISED SPACER |
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BRONCHIAL asthma is a common respiratory disease of childhood. Acute exacebration of asthma is a common, poten-tially life threatening complication. Various guidelines(1-4) have been laid down for the management of asthma. Aerosolized beta-2 agonists are the drugs of choice for an acute exacerbation of bronchial asthma(1). The inhalation route is preferred because of its greater efficacy(5). Recent studies have shown that there is no significant difference between nebulizer and metered dose inhaler (MDI) with spacer for delivery of aerosolized bronchodilators in acute asthma(6-8). In contrast to a nebulizer, MDI with spacer is cheaper, portable, easier to use, less time consuming and needs no power supply(9). Use of spacer eliminates the need for co-ordination of aerosol actuation with inspiration(10) and also decreases oropharyngeal deposi-tion(11,12). Commercial spacers are still expensive and may not be available every-where making it difficult to replace them in case of loss or damage. Indigenous spacer made from a plastic bottle is very cheap and can be made at home, making it easily replaceable. Various authors(13-15) have used indigenous spacers, e.g., coffee cups, plastic bags and found them to be effective in achieving bronchodilation and decreasing oropharyngeal deposition. However, there is paucity of data comparing the efficacy of indigenous spacer with the commercial spacer. The present study was therefore designed to compare the efficacy of valved commercial spacer with non-valved indigenous spacer for delivering aerosolized beta-2 agonist in an acute exacerbation of asthma.
The study was conducted in the Pediatric Emergency Room. Children between 1 to 12 years of age, seeking treatment for an acute exacerbation of bronchial asthma were eligible for enrolment in the study. Bronchial asthma was defined as per Sibbald’s criteria(16) as: "Recurrent episodes of wheezing which occur in response to allergens, exercise or emotions as well as with symptoms suggestive of respiratory infection. On auscultation there would be high pitched wheeze over most parts of the lung". For the purpose of the study, a child should have had at least two such previous episodes and should not have pulmonary tuberculosis, emphysema other cardiac, hepatic, pulmonary or skeletal disease involving the spine or any neuromuscular disorder involving intercostal muscle or diaphragm. Infants were excluded from the study. Children who had already received steroids for the presenting exacerbation of asthma before coming to hospital were also excluded. An informed consent was obtained from parents prior to recruitment. Following recruitment, the children were randomized (computer generated random numbers) into two treatment groups. Group I comprised children who received salbutamol by MDI with commercially available spacer (M/s. Cipla conical valved spacer made of plastic with approximate volume of 750 ml) with or without attached face mask and Group II of those who received salbutamol by MDI with indigenous (improvised) spacer made from a bottle. The commonly available plastic water bottle (1 litre) was adapted to approximate the volume of commercial spacer (750 ml) by cutting it at its mouth-end. The cut-end was padded with plastic adhesive to make it non-traumatic. The base of the bottle was adapted to the MDI mouth piece by cutting in the center, so as to cause minimal leakage of aerosol. The indigenous spacer was tubular and without a valve. A detailed clinical evaluation (history and examination) was recorded on a pre-decided proforma and the severity (mild, moderate, severe) of the acute episode assessed as per guidelines(1). Investigations included peak expiratory flow rate (PEFR) by Wright’s peak flow meter in subjects able to undergo the evaluation and arterial blood gas analysis. After assessment of severity of the attack, all patients were treated according to consensus protocols and no life saving treatment was withheld. Children were given 2 puffs of salbutamol (100 mg) with a gap of 1-2 minutes between the puffs, every 5-10 minutes, using metered dose inhaler with either of the spacers for a total duration of one hour. A face mask was used with commercial spacer in children less than 3 years of age, or in children too sick to use a spacer without a mask. Humidified oxygen was given to all patients at a flow rate of 3-4 L/min. Children were sequentially assessed at 20, 40 and finally at 60 minutes by a single observer (JP) to assess the response to inhaled salbutamol. Response was graded as good, partial or poor as per the guidelines. Cases with incomplete or poor response at 60 minutes were given further treatment according to consensus protocols. children with good response continued to receive inhalation of salbutamol for one hour, frequency of which was gradually decreased and were discharged after a period of stabilization. The differences between the groups were analyzed by chi-square test, Fischer exact test, Student ‘t’ test and analysis of variance, wherever applicable.
Sixty children (30 in each group) fulfilling the study criteria were evaluated. The two groups were comparable (p ³ 0.05) for various characteristics at admission (Table I). The sequential changes in the outcome measures evaluated at 20, 40 and 60 minutes are summarized in Table II. All the outcome measures showed a significant (p <0.05) improvement with time in both the groups, indicating the efficacy of both the spacer devices. After institution of therapy, all the recovery parameters including clinical criteria, PEFR and blood gases were comparable (p ³ 0.05) at all observation points, i.e., 20, 40 and 60 minutes after institution of therapy in the two groups.
Table III outlines the sequential cate-gorization of response in the two groups, as per the guidelines criteria. It is obvious that the MDI with indigenous spacer was equivalent in efficacy to MDI with commercial spacer for administration of salbutamol in acute asthma. At 60 minutes, the total number of patients showing good response was 47 (24 in Group I and 23 in Group II), while 12 patients (5 in Group I and 7 in Group II) had partial response. Only one patient out of the entire study group showed poor response at 60 minutes.
The study was conducted to assess the efficacy of an indigenous spacer in delivering aerozolized beta-2 agonist, in an effort to create a low cost and easily available alternative to an expensive commercial spacer device. With sample size taking the power of study as 80% at an alpha of 0.05 was sufficient to detect a difference in efficacy of 30% between the two methods of treatment. The indigenous spacer used in the study was a tubular non-valved spacer device made of plastic (modified water bottle) with an approximate volume of 750 ml. The results of the study demonstrate that an indigenous spacer is as effective as a commercial spacer for delivery of beta-2 agonist in an acute exacerbation of asthma. Several previous studies have shown MDI with a commercial spacer is an equally efficacious alternative to a nebulizer(6-8). Thus, an indigenous spacer with MDI may be equally effective as a nebulizer. Recommending the use of a nebulizer as the method of choice for delivering aerosolized beta-2 agonists is a difficult proposition for a developing country like India because of economic constraints. Bowton et al.(8) showed a significant reduction in hospital costs following the substitution of MDI with spacer for nebulizer. An average nebulizer unit costs Rs. 3,000-7,000 and a commercial spacer costs Rs. 300-400. These costs may be prohibitive in the context of a country like ours. An indigenous spacer comparatively has negligible cost. Its cost effectiveness is at least 200 times that of a commercial spacer. Different shapes of spacers have been compared for the efficacy. Newman et al.(11) showed that cone spacer increases total pulmonary deposition better than a tube spacer. Toogood et al.(17) also showed cone shaped spacers to be superior. On the other hand, Lulling and co-workers(18) failed to show any difference between pear and tube shaped spacers. There is a direct relationship between the size of spacer and amount of drug delivered leading to increased bronchodilation in children with asthma(19). A better response is obtained with volumes of ³750 ml irrespective of type of spacer. Commercial spacers are provided with valves, which may have problems associated with it. Young children may not be able to open the valve of a commercial spacer, especially in a severe attack. A similar observation was made in this study too, where two of the younger patients with severe attack had difficulty in moving valve of the commercial spacer device. The valve of a commercial spacer tends to become sticky with prolonged use(20), preventing adequate delivery of drug. Levision et al.(21) have shown that non-valved spacers are equally effective. An indigenous spacer circumvents this problem. Small children may not be able to use the mouth piece of a commercial spacer and require a face mask, which entails extra expenditure and may not be easily available. Indigenous spacer overcomes this problem as the size of the mouth end opening can be customized to the child. No studies have been done to recommend the best material for spacer. Ideal material for spacer would be one in which there would be minimal deposition of the drug on the walls of the spacer. Indigenous spacer devices used with MDI earlier have included coffee cups, plastic freezer bags, and plastic bottle, all of which have shown greater bronchodilator response than a MDI alone. In conclusion, metered dose inhaler with improvised spacer device is equivalent in efficacy and a more cost effective alternative to metered dose inhaler with commercial spacer for administration of beta-2 agonist in acute asthma. Contributors: GRS conceived the idea, supervised the data collection, helped in analysis and drafing the manuscript. He will act as guarantor for the paper. JP collected data, helped in analysis and prepared the intitial draft of the paper. VS helped in analysis and preparation of the manuscript. Funding:
Nil.
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