1. Asthma is one of the most common diseases presented to emergency rooms of many hospitals around the world. It is a disease affecting the airways that carry air to and from the lungs. People who suffer from this chronic condition are said to be asthmatic. Chuck, Onorato and Castriotta (1990) explain that the arresting airway inflammation and rapid reversal of bronchospasm are the basis for its treatment. Agents that are commonly used in treating this disease include the combination of corticosteroids and bronchodilating agents. Evidence suggests however, that Heliox may provide additional benefits to patients who often suffer from respiratory emergencies such as asthma.
Heliox, a gaseous mixture of helium and oxygen, is for use in a wide range of respiratory conditions. Chevrolet (2001) describes combining helium and oxygen gas (Heliox) result in a gas with a similar viscosity to air but with a substantially lower density. These mixtures have been used at irregular intervals in respiratory medicine for many years. Furthermore, their use in acute respiratory emergencies such as asthma has been the subject of considerable debate. It was first proposed more than sixty years ago and despite the lapse and encouraging results, Heliox use in routine practice and treating patients with severe acute asthma remains controversial and unclear because of technical implications and high costs.
Beneficial effects have been documented in severe asthma attacks and in patients with chronic obstructive pulmonary disease. Heliox has been also used in the treatment of upper airways obstruction, bronchiolitis and bronchopulmonary dysplasia.
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In a Heliox gas mixture, Chevrolet (2001) adds that helium replaces nitrogen and is generally delivered in concentrations that are three to four times higher than that of oxygen (i.e. 80:20 or 70:30). Despite the medical community’s gravitation toward evidence-based medicine in the 21st century, the clinical effectiveness of Heliox in pediatric patients with airflow obstruction is relatively sparse and is reported primarily through case presentations, case series, or small, uncontrolled studies.
Most clinicians will have encountered patients with airway obstruction where conventional treatment regimes have been inadequate, resulting in serious patient discomfort, escalating intervention, or admission to ICU. Airway obstruction may result from a number of diseases, and can affect both the upper and lower airways. Heliox is a medical gas that rapidly
reduces the respiratory effort associated with airway obstruction and therefore can reduce the work of breathing, which will improve patient comfort (Chevrolet: 2001). It can be used to assist the flow of oxygen into the alveoli of patients with severe respiratory obstruction. Typical examples include Asthma, Bronchiectasis, Bronchiolitis, Chest infection, Chronic Obstructive Pulmonary Disease (COPD), Croup, Epiglottitis, Laryngitis, Stridor, and Tracheitis, among others. Kass and Terregino (1999) state that there are no contraindications for the use of Heliox.
In conclusion, Kass and Terregino (1999) stress that Helium/oxygen mixtures augment, rather than replace, conventional treatments. Heliox does not directly treat the cause of a respiratory condition, but can help relieve symptoms by improving gas exchange in the alveoli, acting as therapeutic bridge until the corticosteroid effect occurs.
2. Hyperventilation is excessive ventilation; specifically: excessive rate and depth of respiration leading to abnormal loss of carbon dioxide from the blood; called also over-ventilation (Saisch, Wessely and Gardner 1996). Hyperventilation can be done on purpose. For example, when a skin diver hyperventilates, he lowers the carbon dioxide levels in his blood and decreases the drive to breathe (most of us are triggered to breathe when the carbon dioxide levels in our blood rise). Saisch, Wessely and Gardner (1996) explain that it can also happen unintentionally and is called psychogenic hyperventilation, hyperventilation syndrome, behavioral breathlessness, or psychogenic dyspnea. It can be noted that hyperventilation results from the underlying behavioral condition. Although the risk of death from psychogenic hyperventilation is low, it can have major impacts on the body (Hernandez et al. 2000)
When carbon dioxide re-breathing is used, Kern and Rosh (n.d.) stresses that hyperventilating patients actually get lower oxygen than is in room air (21%) because very little new oxygen is being added to the paper bag or non-re-breather. The technique suffocates the patient and studies from as long ago as 20 years ago demonstrated re-breathing to be a dangerous treatment technique.
The theory of having a patient re-breathe carbon dioxide, whether from a brown paper bag or a non-re-breather without additional oxygen flowing in, is that “the re-breathed carbon dioxide increases the level of carbon dioxide in the blood and reverses the problems caused by the low blood acid levels caused by low carbon dioxide (Kern and Rosh : n.d.)” There has never been a study to show that this treatment for acute hyperventilation syndrome actually works. What is much more concerning is that there are many deaths from asthma, pulmonary embolus and other organic diseases that resulted from the patient being diagnosed with acute hyperventilation syndrome and not being worked-up or treated for their real underlying disease.
Callahan (1989) adds that a major contributor to these deaths is hypoxia. In pre-hospital adults, it is traditional practice to treat hyperventilation by having patients re-breathe into a brown paper bag. There have been three reported cases in which this treatment, erroneously applied to patients who were hypoxemic or had myocardial ischemia, resulted in death. Researches were done to look into the effects of re-breathing expired air because of this clinical experience.
According to studies, paper bag re-breathing decreases inspired oxygen sufficiently to endanger hypoxic patients. Callahan (1989) states that paper bag re-breathing should never be administered unless myocardial ischemia can be ruled out and the patient’s oxygenation has been directly measured by arterial blood gases or pulse oximetry.
Wijkstra et al (1996) explains that since these conditions are impossible to achieve outside the hospital, its recommendation and use by pre-hospital personnel should be stopped. Likewise, its use in hospital should be diminished. Paper bag re-breathing is often unsuccessful in reversing the symptoms of HVS because patients have difficulty complying with the technique and because CO2 itself may be a chemical trigger for anxiety in these patients explains Callahan (1989). Techniques of re-breathing into a paper bag are no longer recommended because significant hypoxia and death cases have been reported.
3. Labeled in 1878 as “angina epiglottidea anterior”, (1) epiglottitis, or more correctly “supraglottitis is a bacterial cellulitis of the supraglottic structures, most notably the lingual surface of the epiglottis, but also affecting the aryepiglottic folds. As the supraglottic edema increases, the epiglottis is forced posteriorly causing progressive airway obstruction, Myer ; Cressman notes (1994).” Supraglottitis cases in patients under 1 year have been reported, however, it tends to occur in patients aged 2 to 7 years old.
The rapidly progressive symptoms presented by children with acute supraglottitis include severe throat pain, fever, irritability and respiratory distress. Characteristically, Hughes and Lepow (1996) describes the child as toxic appearing, and assumes an upright sitting position, also known as the tripod position, with the chin up and mouth open, often bracing themselves on their hands. Other signs manifested by patients are difficulty in handling their secretions due to severe odynophagia, limited speech due to pain and muffled voice.
According to Cressman ; Myer (1994), Croup refers to the “barking cough that is invariably present with infectious narrowing of the glottis and subglottis, but may be present with many congenital and infectious airway lesions.” Many terms have been applied to infection of the glottic and subglottic regions, but it is most appropriately termed laryngotracheobronchitis (LTB). Unlike the Supraglottitis , the LTB is common in very young children primarily between the ages of 6 months and 3 years. Noted to cause as much as “90% of infectious airway obstructions, Cressman and Myer (1994) stress that 3-5% of children have episodes with 5% of these have recurrent episodes. Confinement is rate (1.5% to 15%) and airway compromises to the point that intubation is required infrequent (1% to 5%).”
LTB Patients typically present with a several day history of upper respiratory-type symptoms progressing to the characteristic barking cough, hoarseness and stridor. The stridor is most commonly inspiratory, with biphasic stridor indicating severe airway compromise. Low grade fever is common, while leukocytosis is inconsistent. In many instances, Rosekrans (1998) stresses that supportive care is all that is required of patients as Laryngotracheobronchitis is most frequently self-limited.” Historically, patients have been treated with humidified air, either from a humidifier or by instructing the child’s parents to sit in the bathroom with a warm shower.
Another upper respiratory disease is the “Bacterial tracheitis, a disease which according to Myer CM (1998) has many synonymous names including bacterial laryngotracheobronchitis, membranous laryngotracheobronchitis and pseudomembranous croup.” It is a rare disease and a potentially life threatening one that should be kept in the differential diagnosis of any child with respiratory distress. It affects children from a wide age range, from 6 months to 8 years with an average of 5 years. The peak incidence is in the fall and winter time.
Several day history of viral upper respiratory symptoms with fever, cough and stridor, similar to LTB are the usual symptoms of a patient suffering from Tracheitis. Other signs include rapid onset of high fever, respiratory distress and toxic appearance. Unlike Supraglottitis, Odynophagia and drooling are absent in Tracheitis. Marked leukocytosis is, however, often noted in patients.
4. The first step in asthma management is environmental control. Asthmatics cannot escape the environment, but through some changes, they can control its impact on their health. Management is important because recorded cases of asthma have increased through the years. The prevalence of this disorder, however, is rising despite advances in therapy. According to Miller and Barbers (1999), it is not clear whether this apparent increase in prevalence is accompanied by an increase in severity of asthma. One potential measure of asthma severity is the requirement for mechanical ventilation. This is also one of the several ways of managing patients with acute, severe asthma.
Corbridge and Hall (1995) state that when a severely asthmatic patient does not respond adequately to medication, prompt intervention by means of noninvasive positive pressure ventilation (NPPV) or invasive positive pressure mechanical ventilation in an effort to provide adequate oxygenation and ventilation is frequently life saving. One of the most important principles of mechanical ventilation in this setting, according to Afzal and Tharatt (2001), is to utilize a strategy aimed at reducing the likelihood that this complication will occur.
The goals of mechanical ventilation are to decrease the work of breathing, maintain adequate oxygenation, and augment alveolar ventilation without causing iatrogenic harm (Corbridge and Hall: 1995). When a patient displays, altered mental status, progressive fatigue as well as clinical deterioration, mechanical ventilation should be immediately considered.
In the past, the ventilator-management strategies used to treat patients with acute asthma resulted in a high risk of morbidity and mortality. Today, according to Richardson and Jagoda (1999), clinicians are gaining a better understanding of the physiological factors that cause dynamic hyperinflation and barotrauma and are improving their ventilator-management strategies, creating better outcomes for their patients. Newer therapies such as non-invasive ventilation and “the use of helium-oxygen mixtures (Kass and Terregino: 1999), are being used to help patients avoid intubation entirely. Most patients with acute, severe asthma can be safely managed today using a combination of these lung-protection strategies, added Freichels (1998).
Bellomo et al, (1994) state that the first concern in the management of a patient suffering from severe asthma is adequacy of the airway. During an asthma attack, the lung condition characterised by laboured breathing. The air passages become narrowed due to muscle spasm and swelling of the mucous membrane lining the lungs. A person with asthma who experiences severe attacks often has an action plan on their person or they know what to do. For patients who are conscious but have difficulty breathing, it is best to give up to 4 lateral chest thrusts and then check the mouth. Lateral chest thrusts are used in an emergency to clear a blockage from their airway.
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