Dose of MgSO4 in asthma is
Bronchodilators Bronchodilator therapy is central to the management of breathlessness. The inhaled route is preferred and a number of different agents delivered by a variety of devices are available. Choice should be informed by patient preference and inhaler assessment. Sho-acting bronchodilators may be used for patients with mild disease but longer-acting bronchodilators are usually more appropriate for those with moderate to severe disease. Significant improvements in breathlessness may be repoed despite minimal changes in FEV1, probably reflecting improvements in lung emptying that reduce dynamic hyperinflation and ease the work of breathing. Oral bronchodilator therapy, such as theophylline preparations, may be contemplated in patients who cannot use inhaled devices efficiently but their use may be limited by side-effects, unpredictable metabolism and drug interactions; hence the requirement to monitor plasma levels. Orally active, highly selective phosphodiesterase inhibitors remain under appraisal. Combined inhaled glucocoicoids and bronchodilators The fixed combination of an inhaled glucocoicoid and a LABA improves lung function, reduces the frequency and severity of exacerbations and improves quality of life. These advantages may be accompanied by an increased risk of pneumonia, paicularly in the elderly. LABA/inhaled glucocoicoid combinations are frequently given with a long-acting muscarinic antagonist (LAMA). LAMAs should be used with caution in patients with significant hea disease or a history of urinary retention. Oral glucocoicoids Oral glucocoicoids are useful during exacerbations but maintenance therapy contributes to osteoporosis and impaired skeletal muscle function, and should be avoided. Oral glucocoicoid trials assist in the diagnosis of asthma but do not predict response to inhaled glucocoicoids in COPD. Pulmonary rehabilitation Exercise should be encouraged at all stages and patients reassured that breathlessness, while distressing, is not dangerous. Multidisciplinary programmes that incorporate physical training, disease education and nutritional counselling reduce symptoms, improve health status and enhance confidence. Most programmes include two to three sessions per week, last between 6 and 12 weeks, and are accompanied by demonstrable and sustained improvements in exercise tolerance and health status. Oxygen therapy Long-term domiciliary oxygen therapy (LTOT) improves survival in selected patients with COPD complicated by severe hypoxaemia (aerial PaO2 < 7.3 kPa (55 mmHg)). It is most conveniently provided by an oxygen concentrator and patients should be instructed to use oxygen for a minimum of 15 hours/ day; greater benefits are seen in those who use it for more than 20 hours/day. The aim of therapy is to increase the PaO2 to at least 8 kPa (60 mmHg) or SaO2 to at least 90%. Ambulatory oxygen therapy should be considered in patients who desaturate on exercise and show objective improvement in exercise capacity and/or dyspnoea with oxygen. Oxygen flow rates should be adjusted to maintain SaO2 above 90%. Surgical intervention Bullectomy may be considered when large bullae compress surrounding normal lung tissue. Patients with predominantly upper lobe emphysema, preserved gas transfer and no evidence of pulmonary hypeension may benefit from lung volume reduction surgery (LVRS), in which peripheral emphysematous lung tissue is resected with the aim of reducing hyperinflation and decreasing the work of breathing. Both bullectomy and LVRS can be performed thorascopically, minimising morbidity. Lung transplantation may benefit carefully selected patients with advanced disease (p. 567). Other measures Patients with COPD should be offered an annual influenza vaccination and, as appropriate, pneumococcal vaccination. Obesity, poor nutrition, depression and social isolation should be identified and, if possible, improved. Mucolytic agents are occasionally used but evidence of benefit is limited. Palliative care Addressing end-of-life needs is an impoant, yet often ignored, aspect of care in advanced disease. Morphine preparations may be used for palliation of breathlessness in advanced disease and benzodiazepines in low dose may reduce anxiety. Decisions regarding resuscitation should be addressed in advance of critical illnes Magnesium sulfate is a bronchodilator. It relaxes the bronchial muscles and expands the airways, allowing more air to flow in and out of the lungs. This can relieve symptoms of asthma, such as shoness of breath. initial loading dose 2 gm over a period of 20 minutes where infused Ref Davidson edition23rd pg 577
8 g i.v. over 20 minutes
2g infused over 20 minutes
2g i.v. over 40 minute
6 g i.V. over 40 minutes
Respiratory system