History

Fact Explanation
Shortness of breath Severe shortness of breath develops at rest and disturbs sleep. Patient can't complete sentences in one breath or is too breathless to talk or feed. Status asthmaticus is the acute severe form of bronchial asthma. Caused by a reversible, recurrent, diffuse obstructive pulmonary disease due to airway inflammation and hyper-reactivity. Smooth muscle spasm, edema of the mucosa and mucous plugging causes airflow obstruction leading to hypercarbia and hypoxia. Status asthmaticus may progress from acute severe to life threatening form. The condition is reversible with aggressive treatment. These symptoms are commoner at night and in the early morning. Symptoms are worse after exercise or exposure to triggers such as dander, cold and damp air or even emotion and laughter. [1,2,3] Male sex is a risk factor for asthma in pre-pubertal children. Female sex is a risk factor for the persistence of asthma into adulthood. [1,2]
Cough Occurs at night along with shortness of breath and wheeze. Non productive despite of mucus obstruction of the airway. [1,2,3]
Wheeze A continuous, coarse, whistling sound produced in an obstructed respiratory airways during expiration. Other respiratory noises, such as stridor or rattly breathing can mimic wheeze. There are several phenotypes of breathing in children that changes with age. They may have a personal or family history of atopic disorders. Co-existent atopy is a risk factor for persistence of wheeze independent of age of presentation.[1,2,3,4,5]
Restlessness This occurs due to brain hypoxia when exacerbation deteriorates further. Patient is usually agitated. [1,2]
Drowsiness Drowsiness occurs due to brain hypoxia (PaO2 less than 60mmHg) when exacerbation deteriorates further. Patient may feel sleepy and confused as well. [1,2,6]
Poor feeding Due to breathlessness and mouth breathing. This is commonly noted by mothers of asthmatic infants. [1,2]
Lack of play Due to breathlessness and fatigue caused by poor sleep. Mother may notice a decreased desire to run and play. He/she may become fatigued easily and cough when exercising. [1,2]
History of preceding respiratory infection Respiratory viruses are the main trigger in exacerbations of asthma. Though the mechanism in not well explained, Respiratory Respiratory Syncytial Virus (RSV) and Rhinovirus have been found as the most common viruses. So most patients with bronchial asthma have a preceding history of respiratory infection. Mother may notice that her child's colds last longer than they do in other children. [7]
Noisy breathing Due to breathlessness. [1,2]
Cyanosis Due to hypoxic state, subcutaneous tissue having low oxygen saturation and high amount of deoxygenate haemoglobin. So, mother may notice that the appearance of the child gets blue or purple discoloration. This includes skin as well as mucous membranes. [1]
Triggering factors There are triggering factors other than preceding respiratory infection such as environmental allergens and irritants (eg- smoking), exercise, emotions, some drugs (eg- aspirin, beta blockers), stress Drugs (eg, aspirin, beta blockers) and changes in weather. [1,2]
References
  1. ØYMAR KNUT, HALVORSEN THOMAS. Emergency presentation and management of acute severe asthma in children. Array [online] 2009 December [viewed 20 May 2014] Available from: doi:10.1186/1757-7241-17-40
  2. BRITISH THORACIC SOCIETY, SCOTTISH INTERCOLLEGIATE GUIDELINES NETWORK. British guideline on the management of asthma. Thorax [online] 2003 Feb:i1-94 [viewed 13 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/12653493
  3. INWALD D., ROLAND M., KUITERT L., MCKENZIE S. A, PETROS A.. Oxygen treatment for acute severe asthma. BMJ [online] 2001 July, 323(7304):98-100 [viewed 20 May 2014] Available from: doi:10.1136/bmj.323.7304.98
  4. NIEVAS IF, ANAND KJ. Severe Acute Asthma Exacerbation in Children: A Stepwise Approach for Escalating Therapy in a Pediatric Intensive Care Unit J Pediatr Pharmacol Ther [online] 2013, 18(2):88-104 [viewed 20 May 2014] Available from: doi:10.5863/1551-6776-18.2.88
  5. NEWTH CHRISTOPHER J.L., MEERT KATHLEEN L., CLARK AMY E., MOLER FRANK W., ZUPPA ATHENA F., BERG ROBERT A., POLLACK MURRAY M., SWARD KATHERINE A., BERGER JOHN T., WESSEL DAVID L., HARRISON RICK E., REARDON JEAN, CARCILLO JOSEPH A., SHANLEY THOMAS P., HOLUBKOV RICHARD, DEAN J. MICHAEL, DOCTOR ALLAN, NICHOLSON CAROL E.. Fatal and Near-Fatal Asthma in Children: The Critical Care Perspective. The Journal of Pediatrics [online] 2012 August, 161(2):214-221.e3 [viewed 20 May 2014] Available from: doi:10.1016/j.jpeds.2012.02.041
  6. POTTER PAUL C. Current guidelines for the management of asthma in young children. Allergy Asthma Immunol Res [online] 2010 December [viewed 21 May 2014] Available from: doi:10.4168/aair.2010.2.1.1
  7. JACKSON DAVID J., SYKES ANNEMARIE, MALLIA PATRICK, JOHNSTON SEBASTIAN L.. Asthma exacerbations: Origin, effect, and prevention. Journal of Allergy and Clinical Immunology [online] 2011 December, 128(6):1165-1174 [viewed 21 May 2014] Available from: doi:10.1016/j.jaci.2011.10.024

Examination

Fact Explanation
Use of accessory muscles Labored breathing against an obstructed airway is supported by accessory muscles such as sternocleidomastoid and the scalenes, that increase the thoracic capacity. Usage of accessory muscles is noted by palpation of neck muscles. [1,2,3,4]
Recessions Sucking in of the skin around the ribs and the top of the sternum is due to labored breathing. Recession is a clinical sign of respiratory distress which occurs as increasingly negative intrathoracic pressures causes in drawing of part of the chest. Suprasternal retractions are commonly present. Other than that recessions are present subcostally (also known as Harrison's sulci) and intercostally. [1,2,4,5]
Prolonged expiration and nasal flaring Air is trapped in the lower airway due to the obstruction. Therefore more effort is required to expel air from the lungs. This causes nasal flaring on inspiration. [1,2,3]
Tachypnoea Tachypnoea is the condition of rapid breathing. Tachypnoea is defined as >40 breaths/min in aged 2-5 years and >30 breaths/min in aged >5 years. [1,6,7]
Rhonchi Rhonchi are continuous, low pitched sounds with a gurgling, snoring or rattle-like quality. It is more common during expiration and usually caused by secretion in bronchial airways. [1,2]
Tachycardia Tachycardia is defined as >140 in children aged 2-5 years and >125 in children aged >5 years. During an acute attack, there is no sufficient air entering the lung which in turn increase the heart rate under autonomic nervous stimulation. Tachycardia can be a sign of severity, but is also a side effect of beta agonist which is used in treatment. Increasing tachycardia generally denotes worsening asthma while a fall in heart rate in life threatening asthma is a pre-terminal event.[1,2,3,4,7]
Silent chest As the disease becomes severe, air flow can dramatically decrease causing silent chest on auscultation while the patient is making severe respiratory effort. It is an ominous sign that indicates severe deterioration of the acute attack and needs immediate attention. Silent chest is commonly accompanied by hypercapnia (increased carbon dioxide levels in the blood) and acidosis, both of which are life- threatening. [1,2]
Altered level of consciousness This occurs due to brain hypoxia when exacerbation deteriorates further. [1,2,6,7]
Orthopnoea The airway size is smaller supine position exaggerating airway obstruction. Accessory muscles can be used more efficiently in erect position. Asthmatics cannot lay flat and prefers to sit up or stand. [1,2,3,5]
Cyanosis It is the appearance of a blue or purple discoloration of the skin or mucous membranes due to subcutaneous tissue having low oxygen saturation. [1,2,5]
Pulsus paradoxus During inspiration the increased negative pressure facilitates venous return and blood gets sequestered in the pulmonary circulation causing the blood pressure to fall.The normal fall in pressure is less than 10 mmH. When the drop is more than 10mm Hg, it is referred to as pulsus paradoxus. Severity of asthma can be assessed. [1,2]
Wheezing Wheeze is a continuous, coarse, whistling sound produced in an obstructed respiratory airways during expiration. However wheezing is a poor indicator of severity of the obstruction as It often increases as the obstruction resolves. It is the absence of wheezing that is important as "silent chest" indicates a life threatening condition with very severe airway limitation. [1,2,3,4]
Sit upright Patient may try to sit upright in order to straighten the airway and ease the breathing. [1]
Diaphoresis Diaphoresis is the state of perspiring profusely. This is mainly due to the higher levels of stress and anxiety that the patient undergoes during a major asthma attack as it triggers autonomic nervous system to cause profuse sweating. [1]
References
  1. NEWTH CHRISTOPHER J.L., MEERT KATHLEEN L., CLARK AMY E., MOLER FRANK W., ZUPPA ATHENA F., BERG ROBERT A., POLLACK MURRAY M., SWARD KATHERINE A., BERGER JOHN T., WESSEL DAVID L., HARRISON RICK E., REARDON JEAN, CARCILLO JOSEPH A., SHANLEY THOMAS P., HOLUBKOV RICHARD, DEAN J. MICHAEL, DOCTOR ALLAN, NICHOLSON CAROL E.. Fatal and Near-Fatal Asthma in Children: The Critical Care Perspective. The Journal of Pediatrics [online] 2012 August, 161(2):214-221.e3 [viewed 20 May 2014] Available from: doi:10.1016/j.jpeds.2012.02.041
  2. ØYMAR KNUT, HALVORSEN THOMAS. Emergency presentation and management of acute severe asthma in children. Array [online] 2009 December [viewed 20 May 2014] Available from: doi:10.1186/1757-7241-17-40
  3. BRITISH THORACIC SOCIETY, SCOTTISH INTERCOLLEGIATE GUIDELINES NETWORK. British guideline on the management of asthma. Thorax [online] 2003 Feb:i1-94 [viewed 13 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/12653493
  4. NIEVAS IF, ANAND KJ. Severe Acute Asthma Exacerbation in Children: A Stepwise Approach for Escalating Therapy in a Pediatric Intensive Care Unit J Pediatr Pharmacol Ther [online] 2013, 18(2):88-104 [viewed 20 May 2014] Available from: doi:10.5863/1551-6776-18.2.88
  5. INWALD D., ROLAND M., KUITERT L., MCKENZIE S. A, PETROS A.. Oxygen treatment for acute severe asthma. BMJ [online] 2001 July, 323(7304):98-100 [viewed 20 May 2014] Available from: doi:10.1136/bmj.323.7304.98
  6. MCFADDEN E. R.. Acute Severe Asthma. Am J Respir Crit Care Med [online] 2003 October, 168(7):740-759 [viewed 12 May 2014] Available from: doi:10.1164/rccm.200208-902SO
  7. REES HA. Management of status asthmaticus. Postgrad Med J [online] 1967 Apr, 43(498):225-233 [viewed 12 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2466299

Differential Diagnoses

Fact Explanation
Foreign body aspiration Sudden onset of coughing, wheezing and decreased breathing sounds. All these may accompanied with hemoptysis, dyspnea, and chest pain. [1]
Pneumonia Gradual onset of fever with productive cough. Commonly bacterial in origin. Chest pain is of pleuritic type. Pneumonia responds to intravenous antibiotics. [2]
Congestive heart failure Congestive cardiac failure can manifest as cough, shortness of breath at rest, fatigue, weakness and fainting. Orthopnoea and paroxysmal nocturnal dyspnea are late signs. On examination there may be hepatomegaly, ankle edema. There may be a past history of congenital heart disease. [3]
Bronchiolitis Bronchiolitis is inflammation of the bronchioles that usually occurs in children less than two years of age with the majority being aged between three and six months. This inflammation is usually caused by respiratory syncytial virus. Nasal obstruction, rhinorrhoea and an irritating cough are noticed first. After 1–3 days there follows increasing tachypnoea and respiratory distress. Fever of 38.5°C or greater is seen in 50% of cases. Auscultatory signs are very variable. Inspiratory crackles are often heard. Expiratory wheeze is often present.[4]
Cystic Fibrosis Cystic fibrosis is an autosomal recessive genetic disorder that affects most critically the lungs, and also the pancreas, liver, and intestine. An abnormality in transportation of chloride and sodium across an epithelium leads to thick, viscous secretions. Patients present with a cough, which is either chronic or recurrent and can be dry, mucoid and purulent. Prolonged symptoms of bronchiolitis occur in infants. [5]
References
  1. QURESHI A, BEHZADI A. Foreign-body aspiration in an adult Can J Surg [online] 2008 Jun, 51(3):E69-E70 [viewed 12 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2496600
  2. MARSH DR, GILROY KE, VAN DE WEERDT R, WANSI E, QAZI S. Community case management of pneumonia: at a tipping point? Bull World Health Organ [online] 2008 May, 86(5):381-389 [viewed 12 May 2014] Available from: doi:10.2471/BLT.07.048462
  3. REDDY S, BAHL A, TALWAR KK. Congestive heart failure in Indians: How do we improve diagnosis & management? Indian J Med Res [online] 2010 Nov, 132(5):549-560 [viewed 12 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3028953
  4. VERMA N, LODHA R, KABRA SK. Recent advances in management of bronchiolitis. Indian Pediatr [online] 2013 Oct, 50(10):939-49 [viewed 20 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/24222284
  5. PIER GB. The challenges and promises of new therapies for cystic fibrosis. J Exp Med [online] 2012 Jul 2, 209(7):1235-9 [viewed 20 May 2014] Available from: doi:10.1084/jem.20121248

Investigations - for Diagnosis

Fact Explanation
Peak flow meter Peak flow meter measures peak expiratory flow rate (PEFR) which is essential in diagnosing and assessing the severity of asthma. It is readily available and reproducible. Peak expiratory flow (PEF) is the maximal flow achieved during the maximally forced expiration initiated at full inspiration, measured in liters per minute or in liters per second. In asthma, peak flow is low as a percentage of predicted value. In status asthmaticus, PEFR is between 33% - 50% of predicted in acute severe asthma and is below 35% of predicted in a life-threatening episode. [1,2,3,4] Above five years of age, conventional lung function testing such as peak flow and spirometry is possible in most children in most settings. But it is difficult to get the coordination from a child that is essential in performing peak flow meter. [1,2,4]
pulse oximetry Provides a vitally important continuous evaluation of oxygen saturation, because hypoxia can be fatal in status asthmaticus. Treatment can be adjusted according to oxygen saturation. The aim of oxygen therapy is to maintain SpO2 (oxygen saturation) above 92%. However, oxygen saturation is not a good parameter of adequate ventilation in children who receive oxygen treatment. Thorough and repeated clinical assessments are required to discover imminent respiratory failure. Intensive inpatient treatment should be considered for children with SpO2 <92% in air after initial bronchodilator treatment. [1,2,3,5]
Arterial blood gas (ABG) analysis ABG is considered if there are features of life threatening asthma not responding to treatment. Arterial ear lobe blood gases gives an accurate measure of pH and pCO2. A finger prick sample is an alternative. Normal or raised pCO2 levels are indicative of worsening asthma. Free flowing venous blood giving a pCO2 measurement of less than 6kPA (45mm Hg) excludes hypercapnia. [1,3,5]
Full blood count Neutrophilic leucocytosis is present in pulmonary infections.[1]
Chest X-ray This is important to exclude pneumonia, persisting unilateral signs suggestive of pneumothorax, pneumomediastinum or heart failure. Signs of chronic obstructive pulmonary disease can also be found out. Chest X-ray is also important in patient who do not respond to therapy. [1,2,6]
Spirometry Although this is an important test, spirometry is less commonly used in acute episodes. FEV1/FVC ratio represents the proportion of a person's vital capacity that they are able to expire in the first second of expiration. This value is below normal in asthma and is between 35% - 50% of predicted in acute severe asthma and is below 35% of predicted in a life-threatening episode. [1,2,6,7] Above five years of age, conventional lung function testing such as peak flow and spirometry is possible in most children in most settings. But it is difficult to get the coordination from a child that is essential in performing peak flow meter. [1,2,4]
References
  1. BRITISH THORACIC SOCIETY, SCOTTISH INTERCOLLEGIATE GUIDELINES NETWORK. British guideline on the management of asthma. Thorax [online] 2003 Feb:i1-94 [viewed 13 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/12653493
  2. REES HA. Management of status asthmaticus. Postgrad Med J [online] 1967 Apr, 43(498):225-233 [viewed 12 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2466299
  3. ØYMAR KNUT, HALVORSEN THOMAS. Emergency presentation and management of acute severe asthma in children. Array [online] 2009 December [viewed 20 May 2014] Available from: doi:10.1186/1757-7241-17-40
  4. NEWTH CHRISTOPHER J.L., MEERT KATHLEEN L., CLARK AMY E., MOLER FRANK W., ZUPPA ATHENA F., BERG ROBERT A., POLLACK MURRAY M., SWARD KATHERINE A., BERGER JOHN T., WESSEL DAVID L., HARRISON RICK E., REARDON JEAN, CARCILLO JOSEPH A., SHANLEY THOMAS P., HOLUBKOV RICHARD, DEAN J. MICHAEL, DOCTOR ALLAN, NICHOLSON CAROL E.. Fatal and Near-Fatal Asthma in Children: The Critical Care Perspective. The Journal of Pediatrics [online] 2012 August, 161(2):214-221.e3 [viewed 20 May 2014] Available from: doi:10.1016/j.jpeds.2012.02.041
  5. NIEVAS IF, ANAND KJ. Severe Acute Asthma Exacerbation in Children: A Stepwise Approach for Escalating Therapy in a Pediatric Intensive Care Unit J Pediatr Pharmacol Ther [online] 2013, 18(2):88-104 [viewed 20 May 2014] Available from: doi:10.5863/1551-6776-18.2.88
  6. INWALD D., ROLAND M., KUITERT L., MCKENZIE S. A, PETROS A.. Oxygen treatment for acute severe asthma. BMJ [online] 2001 July, 323(7304):98-100 [viewed 20 May 2014] Available from: doi:10.1136/bmj.323.7304.98
  7. MCFADDEN E. R.. Acute Severe Asthma. Am J Respir Crit Care Med [online] 2003 October, 168(7):740-759 [viewed 12 May 2014] Available from: doi:10.1164/rccm.200208-902SO

Management - General Measures

Fact Explanation
Fluid management Patients in status asthmaticus are inevitably dehydrated due to poor oral intake, tachypnea, and often emesis. The dehydration often causes a metabolic acidosis as well increasing their work of breathing. Rehydration prevents thickening of mucous secretions and begins to treat the metabolic acidosis. When fluids cannot be taken orally, calculation of the maintenance volume of low solute intravenous fluid should be based on about twice the estimated insensible loss-that is, roughly 50 ml/kg/24 hours. [1,2]
Correction of hypokalaemia This can be resulted from the beta agonist drug therapy. And it should be corrected with intravenous potassium chloride. [1,2]
Anitbiotics This is not routinely done. It is only indicated if there are evidences of a bacterial infection such as pneumonia. [1]
Positioning the patient The patient should be positioned to ease the breathing with straightened airway. Sitting the patient up is preferred. [1,3]
Treatment setting In a case of life threatening asthma, the patient should be transferred to an emergency treatment unit. Other indications are altered consciousness, exhaustion and rising PCO2 despite treatment. [1,3,4]
Secondary prevention The parents and care givers should be thoroughly educated on the prevention of further asthma exacerbation. This includes avoidance of exposure to allergens which may also reduce severity of existing disease. House dust mite control can be achieved by complete barrier bed covering system, removal/high pressure vacuuming of carpets, removal of soft toys from bed or freezing them overnight once a week. Using smooth bed linen and curtains will also be helpful. There are no conclusive evidence regarding impact of dog, cat, and cockroach allergen in reduction of asthma symptoms. However, those who develop attacks on exposure to these should avoid these animals. Parental smoking increases severity of existing asthma. Starting to smoke as a teenager will increase the risk of persisting asthma. Air pollution may provoke acute asthma attack or aggravate existing chronic asthma. When a specific food precipitates asthma in a particular child, it is advisable to avoid such food. Other than that, there are no generalized dietary restrictions. No clear evidence of any benefit from goat’s milk. [5,6,7] Weight reduction is recommended in obese children to improve asthma control. [8]
Chest physiotherapy Chest physiotherapy may augment airway clearance after the acute episode as it can be irritating to the severe asthmatic and may actually worsen clinical symptoms. [9]
Sedation This is generally indicated only for the patients which are intubated. Ketamine by continuous infusion is the first choice for sedation. Fentanyl is the preferred opiate. Vecuronium, a neuromuscular blocking agent facilitates mechanical ventilation. Inhaled general anesthetics are the last resort of sedation when all the other measures fail. Hypotension and cardiac dysrhythmias are important side effects. [9]
References
  1. BRITISH THORACIC SOCIETY, SCOTTISH INTERCOLLEGIATE GUIDELINES NETWORK. British guideline on the management of asthma. Thorax [online] 2003 Feb:i1-94 [viewed 13 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/12653493
  2. POTTER PC, KLEIN M, WEINBERG EG. Hydration in severe acute asthma. Arch Dis Child [online] 1991 Feb, 66(2):216-219 [viewed 20 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1792828
  3. ØYMAR KNUT, HALVORSEN THOMAS. Emergency presentation and management of acute severe asthma in children. Array [online] 2009 December [viewed 20 May 2014] Available from: doi:10.1186/1757-7241-17-40
  4. REES HA. Management of status asthmaticus. Postgrad Med J [online] 1967 Apr, 43(498):225-233 [viewed 12 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2466299
  5. EL-GHITANY EM, ABD EL-SALAM MM. Environmental intervention for house dust mite control in childhood bronchial asthma. Environ Health Prev Med [online] 2012 Sep, 17(5):377-84 [viewed 22 May 2014] Available from: doi:10.1007/s12199-011-0263-5
  6. SAMOLIńSKI B, FRONCZAK A, KUNA P, AKDIS CA, ANTO JM, BIALOSZEWSKI AZ, BURNEY PG, BUSH A, CZUPRYNIAK A, DAHL R, FLOOD B, GALEA G, JUTEL M, KOWALSKI ML, PALKONEN S, PAPADOPOULOS N, RACIBORSKI F, SIENKIEWICZ D, TOMASZEWSKA A, VON MUTIUS E, WILLMAN D, WłODARCZYK A, YUSUF O, ZUBERBIER T, BOUSQUET J, COUNCIL ON THE EUROPEAN UNION. Prevention and control of childhood asthma and allergy in the EU from the public health point of view: Polish Presidency of the European Union. Allergy [online] 2012 Jun, 67(6):726-31 [viewed 22 May 2014] Available from: doi:10.1111/j.1398-9995.2012.02822.x
  7. MARTINEZ FERNANDO D.. New insights into the natural history of asthma: Primary prevention on the horizon. Journal of Allergy and Clinical Immunology [online] 2011 November, 128(5):939-945 [viewed 22 May 2014] Available from: doi:10.1016/j.jaci.2011.09.020
  8. MUSAAD SM, PAIGE KN, TERAN-GARCIA M, DONOVAN SM, FIESE BH, THE STRONG KIDS RESEARCH TEAM. Childhood overweight/obesity and pediatric asthma: the role of parental perception of child weight status. Nutrients [online] 2013 Sep 23, 5(9):3713-29 [viewed 22 May 2014] Available from: doi:10.3390/nu5093713
  9. KITULWATTE,N.C. Acute severe asthma, sljch [online]. 2011, 40,18-25. [viewed 22 May 2014] Available from: 10.4038/sljch.v39i4.2864

Management - Specific Treatments

Fact Explanation
Oxygen therapy Many patients with acute severe asthma are hypoxemic. Therefore, oxygen therapy is essential. High flow oxygen at a sufficient flow rate can be administered. [1,2] There are several means of oxygen administration. Headbox, holding an oxygen line to the infant’s face, and facemask are non invasive methods which should be used according to the age of the child. Insertion of cannulae or catheters are less invasive methods compared to intubation. Non invasive methods such as head box needs a high flow rate to achieve adequate oxygenation whereas semi invasive methods need less. Head box can warm oxygen and can administer in high concentrations. Oxygen can be given quickly with face mask. It helpful to administer oxygen for short period of time. Feeding is difficult when a face mask is connected and it is difficult to keep in place. Face mask is used for older children whereas head box is used for young children. The usual flow rate through a face mask is 6-8 L/min and 2L/min through a nasal cannula. [3,4] With continuous monitoring, oxygen can be easily titrated to maintain the patient’s oxygen saturation between 94 - 98%. In significant hypoxemia, mechanical ventilation with tracheal intubation are indicated for respiratory failure. [1,2]
Beta-2 agonists The first line of therapy. Beta 2 agonists act on beta2-adrenergic receptor, thereby causing smooth muscle relaxation, resulting in dilation of bronchial passages. Nebulized beta 2 agonists are recommended as frequent doses driven by oxygen. (2.5-5 mg salbutamol or 5-10 mg terbutaline) Continue nebulization every 20-30 mins or maintain continuous nebulization initially and every 1-4 hourly later on.Assess response to treatment with respiratory rate, heart rate and oxygen saturation every 1-4 hours. [1,2,3,4]
Anticholinergics nebulisation They block the neurotransmitter acetylcholine in the peripheral nervous system thereby causing smooth muscle relaxation, resulting in dilation of bronchial passages. Combining nebulised ipratropium bromide (0.25 mg) with a nebulised β2 agonist produces significantly greater bronchodilation than a β2 agonist alone. The ipratropium dose should be weaned to 4-6 hourly or discontinued. [1,2,5,6]
Oral steroids Steroids are the most important treatment for status asthmaticus. The anti inflammatory effect of steroids reduces the mucosal inflammation and secretions, clearing the air way. The usual dose is oral prednisolone is 10 mg of soluble preparation for children less than 2 years old, 20 mg for children 2-5 years old and 30-40 mg for children >5 years. It should be continued for at least five days or until recovery. Tapering the dose of steroid tablets at the end of treatment is not necessary. A soluble preparation dissolved in a spoonful of water used in those unable to swallow tablets. [1,2,3] Dose of prednisolone should be repeated in children who vomit and IV steroids should be considered in those who are unable to retain orally ingested medication. [1]
Intravenous hydrocortisone Oral and intravenous steroids are of similar efficacy. Parenteral hydrocortisone (4 mg/kg repeated four-hourly) should be reserved for severely affected children and can be used as an alternative for oral prednisolone. []
Intravenous Aminophylline Aminophylline is a compound of the bronchodilator theophylline with ethylenediamine. It is a methylated xanthine derivative that causes bronchodilation. If IV aminophylline is given to patients on oral aminophylline or theophylline, blood levels should be checked. Aminophylline should be considered only for children with severe or life threatening bronchospasm unresponsive to maximal doses of bronchodilators plus steroids. A loading dose of 5 mg/kg should be given over 20 minutes with ECG monitoring followed by a continuous infusion at 1 mg/kg/hour. [1,2]
Intravenous magnesium sulphate Magnesium sulfate seems to be beneficial in the treatment of moderate to severe asthma in children over 5 years. Its bronchodilating and anti inflammatory effects are encouraging as an adjuvant therapy for pediatric patients who do not respond to conventional treatment in acute severe exacerbations. ƒƒIV magnesium sulphate up to 40 mg/kg/day (maximum 2 g) by slow infusion have been used following consultation with senior medical staff. Magnesium should also be considered as a prophylactic treatment.[1,5]
Intravenous Beta-2 agonists Early single bolus dose of IV salbutamol (15 mcg/kg over 10 minutes) is beneficial in some patients with acute severe asthma along with inhaled bronchodilator therapy. Serum electrolyte levels should be assessed regularly as serum potassium levels are often low after multiple doses of beta-2 agonists and should be replaced. [1,2,3,4]
Mechanical ventilation This is considered as a last treatment option in patients with apnea or respiratory arrest and with diminishing level of consciousness. Mechanical ventilation needs careful monitoring. The usual duration of mechanical ventilation is 72 hours, yet can be lengthen. Nasotracheal route is avoided. Intubation should be done before the crisis of respiratory arrest occurs. A suitable endotracheal tube should be selected. Positive airway pressure (BiPAP) may improve symptoms and ventilation without significant adverse events and reduces the risk of intubation and mechanical ventilation. Intubation and positive pressure ventilation increases bronchoconstriction, increase the risk of airway leakage and has adverse effects on circulation and cardiac output. [1,2,3,5,6]
Therapeutic bronchoscopy There are studies suggest that support that bronchoscopy may facilitate respiratory recovery in patients with resistant status asthmaticus who are on mechanical ventilation. [7]
Helium oxygen Helium-oxygen (Heliox) remains unproven therapy. But is regarded as an adjunct therapy when the patient is not improving with conventional therapy or high pressure mechanical ventilation.
References
  1. BRITISH THORACIC SOCIETY, SCOTTISH INTERCOLLEGIATE GUIDELINES NETWORK. British guideline on the management of asthma. Thorax [online] 2003 Feb:i1-94 [viewed 13 May 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/12653493
  2. NEWTH CHRISTOPHER J.L., MEERT KATHLEEN L., CLARK AMY E., MOLER FRANK W., ZUPPA ATHENA F., BERG ROBERT A., POLLACK MURRAY M., SWARD KATHERINE A., BERGER JOHN T., WESSEL DAVID L., HARRISON RICK E., REARDON JEAN, CARCILLO JOSEPH A., SHANLEY THOMAS P., HOLUBKOV RICHARD, DEAN J. MICHAEL, DOCTOR ALLAN, NICHOLSON CAROL E.. Fatal and Near-Fatal Asthma in Children: The Critical Care Perspective. The Journal of Pediatrics [online] 2012 August, 161(2):214-221.e3 [viewed 20 May 2014] Available from: doi:10.1016/j.jpeds.2012.02.041
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