Showing papers in "Respiratory Care Clinics of North America in 1999"

Hyperbaric oxygen in the treatment of life-threatening soft-tissue infections.

Abstract: Necrotizing soft-tissue infections are rapidly spreading bacterial infections that account for a relatively small proportion of infections, but are aggressive in nature and nearly uniformly fatal if left untreated. Prompt recognition, antibiotic therapy, aggressive surgical debridement, and hyperbaric oxygen (HBO) therapy have reduced the mortality resulting from these infections. Oxygen, at increased pressures, augments tissue oxygen partial pressure, allowing increased bacterial killing by providing substrate for the formation of oxygen free radicals and augmenting respiratory burst. During the healing process, hyperoxia causes increased formation of capillaries for oxygen, nutrient, and antibiotic delivery, leading to increased efficacy of some antibiotics in the high oxygen environment, and possibly more rapid overall wound healing. Although there are no randomized trials of HBO in these infections, in vitro data and meta-analysis of clinical cases strongly support the use of HBO.

Treatment of decompression illness and latrogenic gas embolism.

Abstract: The mainstay of treatment of gas bubble disease is therapeutic recompression while the patient is breathing oxygen. The patient should be recompressed as soon as possible; however, patients should be considered for recompression even after several days' delay. Treatments should be repeated if possible until symptoms have either resolved or stabilized. Appropriate hydration is essential. The use of HBO is generally safe, relatively nontoxic, and is possible even in neonates. Pharmacologic agents (e.g., anticoagulants, lidocaine, antiplatelet agents, corticosteroids, inhibitors of calcium flux) may be useful adjuncts to recompression therapy but they require further study. For patients who respond poorly to recompression therapy, the next advance in the treatment of DCI-induced neural injury is likely to be due to the development of agents that reduce the effects of reperfusion injury and delayed cell death.

Diagnosis and treatment of carbon monoxide poisoning

Abstract: Carbon monoxide (CO) poisoning is a common occurrence in today's society. Most such poisonings are a direct consequence of inhaling the toxic byproducts of combustion. Exposure to toxic amounts of CO occurs most often during inhalation of automobile exhaust or smoke resulting either from faulty heating systems or industrial accidents. CO poisoning is associated primarily with injury to the brain and the heart because the gas binds to hemoglobin and interferes with these organs' need for a continuous supply of oxygen. Prompt recognition of CO poisoning and treatment of the patient with oxygen are essential to prevent long-term damage and delayed neurologic sequelae.

Diagnosis and treatment of insomnia.

Abstract: Insomnia is an extremely common complaint. Frequently, it occurs secondary to a number of medical and psychiatric conditions that directly affect the ability to initiate or maintain sleep. Insomnia can also occur secondary to behavioral factors, such as shift work, whereby patients either do not follow or control the dictates of their internal circadian rhythm or develop inappropriate conditioned responses to their sleep surroundings. Insomnia can be a primary and even lifelong complaint. Patients with primary insomnia probably have a physiologic problem that has not been clearly identified as the basis for their subjective complaint.

Physiology of hyperbaric hyperoxia.

Abstract: This article reviews the essential physiology of oxygen exchange in the lungs, oxygen transport to tissue, and oxygen utilization by the body tissues. The physiologic effects of hyperbaric hyperoxia are summarized, with an emphasis on the circulatory responses to hyperoxia. Finally, the effects of hyperoxia on normal cellular processes are discussed.

The spectrum of sleep-disordered breathing.

Abstract: The term sleep-disordered breathing has been used synonymously with the term obstructive sleep apnea syndrome (OSAS). In a broader sense, however, the disorders of breathing during sleep exist along a spectrum of severity. The mildest form of sleep-related breathing disorder is intermittent snoring, which is primarily a nuisance without significant health sequelae. The most severe form of disordered breathing is the obesity-hypoventilation syndrome, which is associated with severe morbidity and very high mortality. In between these two extremes are disorders of gradually increasing impact on morbidity and mortality: persistent snoring, upper airway resistance syndrome, and OSAS.

Comparative potency and clinical efficacy of inhaled corticosteroids.

Abstract: The inhaled corticosteroids (ICSs) are currently the most potent antiinflammatory drugs available for the long-term control of persistent asthma. Physico-chemical modifications of the basic steroid structure result in pharmacodynamic and pharmacokinetic properties that confer both enhanced topical efficacy and diminished systemic activity compared with older corticosteroids such as prednisolone. The purpose of this article is to compare the pharmacodynamic, pharmacokinetic, and lung delivery differences among the products and demonstrate how those differences translate into significant differences in the clinical effectiveness of the ICSs.

Assessment of tissue oxygenation.

Abstract: A continuous supply of oxygen to all tissues is necessary for the efficient production of ATP, and this supply is considered sufficient when aerobic metabolism is maintained. Nonhealing wounds, necrotizing infections, radiation-induced necrosis, crush injury, decompression illness, and CO poisoning all exhibit impaired tissue oxygenation. The need for efficacy of HBO therapy in such conditions is in part determined by the prevailing state of tissue oxygen supply and demand. The methods currently available or under development for assessing the adequacy of tissue oxygenation include blood gas analysis, transcutaneous oxygen measurement, gastric tonometry, pulse oximetry, near-infrared spectroscopy, functional MR imaging, MR spectroscopy, electron paramagnetic resonance, positron emission tomography, and single photon emission computed tomography. The clinical and experimental applications of these methods are discussed and emphasis is placed on their role in hyperbaric medicine.

Exogenous surfactant therapy in newborns.

Abstract: The introduction of surfactant replacement therapy for the management of respiratory distress syndrome (RDS) in the premature infant is one of the major advances in neonatal intensive care. After almost 50 years of intense research, the concerted efforts of basic scientists and clinicians have been rewarded. Despite the remarkable effects of surfactant therapy of RDS, the impact on the incidence of chronic lung disease has been unclear. With the recognition of the role of surfactant inactivation in the pathogenesis of other respiratory disorders of newborns (i.e., meconium aspiration syndrome and pneumonia) newer applications as well as new challenges have emerged. This article provides an overview of the physiology of the surfactant system and the current uses of this therapy in newborns.

Normal human sleep.

Abstract: Human sleep is an integral part of the basic rest-activity cycle that is found in all life forms. Comprised of cycling episodes of non-REM (NREM) and REM sleep, sleep can be measured and quantified by electrophysiologic, physiologic, and behavioral indices. Physiologic homeostasis changes markedly between wakefulness, NREM sleep, and REM sleep; moreover, many interacting factors determine sleep organization and sleep quality in a given individual. For the health practitioner, basic knowledge of sleep physiology and sleep modifiers is essential for the treatment of many clinical problems that are directly or indirectly related to phenomena occurring during sleep.

Mucus-controlling agents: past and present.

Abstract: Airway mucus is the secretory product of the mucous cells The mucus is a variable mixture of water, mucous glycoproteins, low molecular weight ions, proteins, and lipids, the physical properties of which are important for airway defense The factors that contribute to the physical properties of mucus are complex, and there are several pharmacologic strategies that potentially can serve to improve the clearability of airway mucus In vitro results suggest potential benefit from the additive effects of selected combinations of mucoactive medications Further studies are required to confirm these findings, to perform direct assessments of mucus clearability, and to extend the observations to patients with various types of pulmonary diseases for which mucoactive treatments are required

Inhaled antimicrobial therapy.

Abstract: Although antimicrobial therapy has been administered through the inhaled route for decades, it has always been controversial There are relatively few accepted indications for this mode of administration Well-controlled studies of aerosolized antibiotics in cystic fibrosis demonstrate that tobramycin on a cyclical basis may reduce sputum volume, bacterial counts, and improve pulmonary function Preliminary data indicate that inhaled antibiotic therapy of ventilator-associated tracheobronchitis may reduce sputum volume, but the clinical significance of this finding remains to be determined Inhaled pentamidine is used for prophylaxis of Pneumocystis carinii in patients with human immunodeficiency virus infection who are intolerant of oral prophylactic agents Ribavirin has been used for 30 years to treat respiratory syncytial virus The role, if any, of inhaled antifungal therapy with amphotericin B remains undetermined

Sleep-disordered breathing in infants and children.

Abstract: Sleep-disordered breathing (SDB) is underdiagnosed in infants and children. In addition to causing physical ailments that range from failure to thrive to cor pulmonale, SDB is often an unrecognized cause of failure in school or of behavioral disorders. Diagnosis of SDB requires a careful and detailed history and physical examination. Polysomnography is required to determine the nature of the problems, the magnitude of the physiologic disturbance, and, ultimately, the significance of the problem for the child. Earlier recognition, accurate diagnosis, and appropriate treatment should alleviate much of the childhood morbidity associated with these conditions.

Operational use and patient monitoring in a multiplace hyperbaric chamber

Abstract: Multiplace hyperbaric chambers can be used to deliver patient care with enormous flexibility. Standard critical care techniques, such as mechanical ventilation, endotracheal suctioning, hemodynamic monitoring, blood gas measurement, and emergency therapy such as cardiopulmonary resuscitation, including defibrillation and cardioversion, can all be performed inside a multiplace chamber. The multiplace chamber can be considered an extension of the intensive care unit. This flexibility is accompanied by increased complexity of chamber operation. Careful attention must be paid to minimization of fire hazards and maintenance of a safe chamber atmosphere. Although life support apparatus can easily be taken inside the chamber and will usually work under hyperbaric conditions, care must be given to facilitate the benefits to the patient of hyperbaric oxygen treatment in the face of potential risks associated with rapid changes in environmental pressure and the partial pressures of the component gases.

Hyperbaric oxygen therapy: from the nineteenth to the twenty-first century.

Abstract: Hyperbaric oxygen technology now occupies a legitimate place in modern medical practice, and the number of clinically active hyperbaric facilities has grown. We estimate that more than 200 monoplace (single-patient) chambers and over two dozen multiplace facilities are presently active in the United States. Nevertheless, the majority of patients suffering from syndromes amenable to HBO therapy are treated in hospitals devoid of such modalities. This situation stems in part from the significant cost of appropriate facilities, the relative scarcity of trained personnel, and the difficulties in obtaining appropriate compensation in an era of rapidly changing reimbursement paradigms. Frequently, patients undergoing HBO therapy require mechanical ventilation, vasoactive drug infusions, sophisticated monitoring, and accurate fluid and electrolyte therapy during treatment. The demonstrated efficacy of HBO as an important part of the treatment of certain acute disease processes, however, justifies the facilities and skilled personnel necessary for the care of critically ill patients in a hyperbaric environment.

Inhaled nonsteroidal anti-inflammatory medications in the treatment of asthma.

Abstract: Asthma is characterized by airway inflammation even in the mildest cases. Multiple studies have confirmed evidence of significant elevations of inflammatory cells and mediators even at baseline in the airway of asthmatics. Cromolyn sodium (SCG) and nedocromil sodium (NS), the "nonsteroidal anti-inflammatory agents" are considered options for the management of mild persistent asthma in both adults and children as outlined by the Global Initiative for Asthma and the Expert Panel II, National Asthma Education and Prevention Program 1997 guidelines. These drugs may inhibit both the early and late asthmatic response, ostensibly by stabilizing mast cells and by reducing the total number of eosinophils and their recruitment. SCG and NS have extremely safe profiles, making them attractive for use even in young children. In addition to daily use for mild persistent asthma, SCG and NS are effective inhibitors of exercise-induced bronchospasm (EIB). Although these drugs are unlikely to eliminate the use of inhaled corticosteroids in patients with more significant obstructive airway disease, they have potentially beneficial steroid-sparing effects. Thus, the cromione, SCG and NS, are effective prophylactic drugs recommended for use in both adults and children in the management of mild persistent asthma, EIB, and potentially as modest steroid-sparing agents.

Sleep in the Elderly

Abstract: Older adults frequently experience difficulties with sleep that can be caused by specific sleep disorders (such as sleep-disordered breathing or periodic limb movements in sleep) and circadian rhythm disturbances. These all can be effectively treated. Medical illnesses and medications also can have a negative affect on sleep and effective management of these can significantly improve sleep in older adults. Sleep in institutionalized older adults is even more disturbed than sleep of community-dwelling older people and special considerations can be made to improve the quality of sleep in institutional settings.

Sleep in patients with respiratory disease.

Abstract: Recent studies have emphasized the high prevalence and significant consequences of sleep abnormalities in patients who have underlying respiratory disease. Such abnormalities include the nocturnal increase in airway resistance in patients who have asthma, the impaired sleep quality and nocturnal desaturation (particularly during REM sleep) in patients who have chronic obstructive pulmonary disease, and the sleep-related hypoventilation and hypoxemia in patients who have various restrictive respiratory disorders. This article discusses the salient features, underlying pathophysiologic mechanisms, and treatment of these abnormalities of sleep in patients who have respiratory disease.

Narcolepsy and other causes of excessive daytime sleepiness.

Abstract: Narcolepsy is a chronic disorder characterized by excessive daytime sleepiness, cataplexy, and other auxiliary symptoms. An interview can ascertain specific symptomatology, whereas a polysomnogram can reveal distinct clinical features. The clinical and laboratory evaluation together enable an accurate diagnosis of narcolepsy. This diagnosis includes a wide spectrum of symptom combinations. Treatment of narcolepsy should include the empathic guidance of a sleep clinician, an emphasis on sleep hygiene, and in many cases pharmacotherapy.

The evolution of beta-agonists

Abstract: Inhaled beta-agonists have become the mainstay of bronchodilator therapy for reactive airway diseases, either alone or in conjunction with other medications. The history of the development of beta-agonists is a fascinating one that spans more than 5000 years. Scientific investigation for the past several hundred years has elucidated the physiology of bronchoconstriction and bronchodilation. In the past decade, a wealth of knowledge has come forth since the discovery of the beta-adrenoceptor which, along with advances in pharmacology, have helped answer the questions of how beta-agonists work. From these advancements, three classes of beta-agonists have been developed: catecholamines, resorcinols, and saligenins. The chemical structures of the more commonly used agents in each class, their interaction with the beta-adrenoceptor, and their beneficial and adverse effects are discussed. Review of the duration of action of these agents may suggest a new way of classifying them into ultrashort-acting, short-acting, intermediate-acting, and long-acting.

Operational use and patient care in the monoplace hyperbaric chamber.

Abstract: The author has made an attempt to describe presently available monoplace chambers, provide codes for their appropriate use in hospitals, and emphasize chamber safety. If appropriate safety precautions are not strictly adhered to, catastrophic accidents may occur, and have occurred. Critically ill patients may have indications for HBO and, indeed, can be treated with HBO in the monoplace chamber. This requires strict attention to detail and an understanding of critical care medicine as well as hyperbaric medicine. To facilitate care of these patients within the monoplace chamber several modifications have been implemented. Complete pulmonary and arterial hemodynamic monitoring, transcutaneous and laser Doppler monitoring, as well as vasopressors, sedation, paralysis, and mechanical ventilation can be supplied to patients treated with HBO within a monoplace chamber (Fig. 19). Suction within the monoplace chamber can be accomplished by adapting existing hospital equipment. Likewise, air breaks can be provided to all patients in the monoplace chamber, including those who are intubated and mechanically ventilated. These modifications have been presented here. Hemodynamic and intravenous access to the critically ill patient is important. Physiologic pressures, ECG, and typical intravenous setups have been described. Several techniques that the author has have personally found helpful have also been provided. The final section of this article presents clinical observations in a few critically ill patients. These anecdotes were only included to try to stimulate thought and hopefully an interchange of ideas that may help us deal more effectively with the management of these patients. This article also raises the question of what is the optimal arterial partial pressure of oxygen as opposed to merely treating the HBO patient with a standard protocol, particularly if the patient has a significant right-to-left shunt (anatomic or physiologic). It is hoped that further discussion, thought, and research can help elucidate answers to these questions.

Medical field management of the injured diver.

Abstract: This article discusses the history of medical field management of the injured diver, and presents a comprehensive medical equipment list for field treatment as well as treatment protocols Case reports are used to illustrate the principles and outcome of medical field management

Treatment of obstructive sleep apnea.

Abstract: Options for the treatment of obstructive sleep apnea are varied and ever-expanding. This article reviews the currently available treatment modalities in an evidence-based format. Focus is placed on the efficacy and limitations of each particular therapy.

The pharmacology of aerosolized airway challenge.

Abstract: Clinicians who perform and interpret airway challenge tests must understand the pharmacology involved. This knowledge helps one appreciate the need for certain procedures and the importance of proper technique. Methacholine and histamine are the most commonly used airway challenge agents. The authors review the pharmacology of methacholine and histamine airway challenge testing and discuss issues regarding the performance and interpretation of an airway challenge test.

Clinical and laboratory evaluations of excessive daytime sleepiness.

Abstract: Sleepiness is common, dangerous, and difficult to quantitate. Sleepiness normally occurs if one tries to be awake during the circadian sleepiness phase or if one obtains insufficient sleep. Certain subjective tests of sleepiness can help the clinician to quantitate historical sleepiness. Objective tests of sleepiness are validated but imperfect predictors of future sleepiness. In spite of the difficulty in measuring sleepiness, a careful clinical evaluation of patients who complain of sleepiness is possible and usually reveals the correct diagnosis.