Respiratory care clinics of North America最新文献

The use of NIV has been shown to facilitate discontinuing ventilatory dependence as well as provide support for adult patients with chronic lung disease without the need for endotracheal intubation. In fact, NIV has recently described as a potential support strategy following extubation failure. Therefore, using NIV as a bridge to liberation from mechanical ventilation may decrease many of the complications associated with long-term use of invasive airway devices as well complications from reinsertion of an artificial airway. Although firm data supporting the use of NIV in the adult population exists, the use of NIV in the pediatric population is based primarily on a series of case studies, retrospective chart reviews, and extrapolation from the adult data. The use of NIV for infants and children remains controversial. The important question to be asked is why there is a lack of randomized controlled trials on NIV in pediatrics? The answer lies somewhere between the lack of equipment designed specifically for pediatrics and the smaller number of patients available compared with adults. Data from the adult population may be more readily adapted to older children; however, it remains difficult to determine the criteria for noninvasive ventilatory use in infants and young children. In fact, this lack of data makes the formulation of firm selection guidelines for infants and children essentially impossible. However, for a select groups of pediatric patients with acute respiratory failure for whom an appropriate noninvasive device with interface is available, a trial of NIV may be seem reasonable to avoid the known negative effects of intubation and invasive mechanical ventilation.

The lack of published evidence supporting the use of APRV in the pediatric critical care patient population may diminish its effective application in respiratory failure. The effect of APRV on the number of ventilator days, ICU stay, and mortality still remains to be studied. Further application of APRV in the role of rest settings for ECMO especially in the pediatric cardiac patient population needs to be investigated. Will the use of APRV decrease the time for adequate lung recruitment, decrease sheer trauma, and/or promote earlier decannulation upon the restoration of tolerable cardiac function? Can APRV be utilized as a re-recruitment maneuver? A comparison of APRV over sustained in a randomized-controlled fashion, will there be a significant difference in ventilator days, length of ICU stay, and/or mortality? Does re-recruitment at plateau pressures during suctioning, patient position changes, or in the face of increased airway resistance decrease the number of ventilator days, length of ICU stay, and/or mortality? Does the use of continuous monitoring of carbon dioxide production aid in optimizing P(high)? The list of questions, both speculative and scientific are too numerous to list. Speculation leads to inquiry which over time drives science. More focus is needed on randomized, controlled trials. Initially the comparison of APRV to HFOV needs to be the primary focus for a proactive approach for ALI. Once a comfort level is established with this modality, further scientific inquires will follow. In the meantime, its use is likely to remain controversial.

The application of positive-pressure mechanical ventilation is one of the cornerstones of support for patients with acute respiratory failure. Unfortunately, the clinical condition of some patients does not improve, despite escalating ventilatory support. Adjunctive therapies to mechanical ventilation such as nitric oxide and heliox have been explored for the purposes of minimizing injurious settings and supporting adequate gas exchange. As specific therapies continue to evolve, clinicians should have a clear understanding of the physiologic basis and evidence before deciding to use any adjunctive therapy. This article discusses the role of nitric oxide and heliox as adjunct therapies to mechanical ventilation. Many questions remain about the role of these unique gases in the management of pediatric patients with acute respiratory failure. Should nitric oxide be used outside of its approved indication, and should heliox be used at all due to the lack of definitive evidence?

The adverse effects of high oxygen levels have been widely reported, and clinicians have struggled for many years to find the ideal balance between inspired oxygen levels and acceptable arterial oxygen saturation. However, when asked "what is an acceptable oxygen saturation," one is hard pressed to find a definitive answer. Permissive hypoxemia is a concept similar to the well-described strategy of permissive hypercapnia. It is a strategy that allows the arterial oxygen saturation to be less than normal in an attempt to minimize the amount of artificial support provided to the lungs by mechanical ventilation. It must be noted that this concept is predominantly based on physiology, as data in the medical literature are very limited. Permissive hypoxemia as an approach to acute lung injury remains controversial in the clinical setting.

Both HFOV and HFJV are important adjuncts to the ventilatory care of sick infants and children. Today, it is important that neonatologists, pediatric intensivists, and respiratory care practitioners understand these ventilators and the options they provide. It is no longer necessary to continue the use of damaging pressures and volumes with CV simply because no other option is available. The clinician who understands not only the pathology and physiology of the underlying lung condition but also understands the available choices in ventilators, how each ventilator functions, and what potential advantage it may offer his patients is able to provide the best possible care to these critically ill patients.

Management of mechanical ventilation is a complex process with outcomes affected by multiple patient and caregiver variable. Well-constructed protocols represent the synthesis of best available evidence regarding ventilator management. In adults, protocols improve important outcomes such as duration of mechanical ventilation, length of stay, and complication rates; however, protocols are not uniformly successful. In pediatrics, the available evidence does not suggest that ventilator management protocols should be adopted routinely, which may be due to pediatric-specific attributes such as a generally shorter weaning duration. Evidence suggests support for protocols to carefully titrate sedation. In addition, daily assessment of SBTs improves patient outcomes and should be more uniformly adopted in pediatrics. Ventilator-related outcomes may be affected by other confounding factors such as nutrition and fluid balance. Specific subpopulations, such as children who have congenital heart disease, may present opportunities for focused use of ventilator management protocols. Protocolized ventilation has an important place in trials of new therapeutic strategies such as surfactant or proning. It is hoped that future research will further define the appropriate use of protocols in the general PICU population. Although specific protocols cannot be routinely recommended, a multidisciplinary team approach to synthesizing available literature and determining best practice is a useful model. This approach will foster "team ownership" of ventilator management by all involved, thus engendering the best possible outcomes for critically ill children who require mechanical ventilation.

Predictors of extubation outcome attempt to provide objective data that may help to modify clinical decision making at the bedside. This article reviews the subjective and objective extubation readiness predictors tested in the pediatric medical literature. An understanding of the predictive capacity of the extubation criteria is vital for the critical care physician. No test is likely to predict the extubation outcome for an individual patient with absolute certainly. Therefore, weaning and extubation practices in the pediatric critical care setting remain variable, and teh development of standardized protocols for extubation remains controversial. Perhaps future well-designed, large-scale trials will provide more accurate predictors of extubation readiness to guide the safe and timely extubation of the pediatric patient.

With most patients in modern ICUs requiring mechanical ventilation, any technology that may lead to more optimal ventilatory strategies would be invaluable in the management of critically ill patients. The focus of most ventilator strategies is protecting the lung from the deleterious effects of mechanical ventilation. Every effort is made to minimize the duration of mechanical ventilation while optimizing the potential for successful extubation. A concise organized plan based on objective criteria that is adjusted to meet changes in patient status is clearly recommended. Continuous capnographic monitoring provides clinicians with clear, precise, objective data that may prove beneficial in the design and implementation of mechanical ventilatory strategies. There are no clear-cut methods for achieving the optimal ventilator strategy for a specific patient. Although guidelines and management theories exist throughout the medical literature, in practice, they often merely serve as loose guidelines. The dynamic properties of an acutely ill patient make the management of mechanical ventilation an ongoing process requiring clinical assessment and planning by multidisciplinary members of the patient care team. Comprehensive evaluation of ventilatory management strategies and patient responses must be made by a collaborative effort of physicians, respiratory care practitioners, and nurses. An objective, consistent approach to the overall management is essential. Although still controversial, it is the authors' opinion that volumetric capnograph provides the data necessary to establish adequate gas delivery, optimal PEEP, and effective ventilation with the least amount of mechanical assistance, regardless of clinician or institutional preferences.

Every publication to date reporting the outcome of intensive care support for pediatric SCT patients must be viewed with caution because all are single-institution, retrospective reports. Nevertheless, some of the conclusions made by these investigators appear to be clinically relevant. First, an SCT patient who requires intensive care support does not automatically have a dismal chance of survival. Survival rates in recent reports range from 15% to 36%, which is reasonable when the overall post-transplant survival rate for non-ICU patients may be only 50%. Second, adverse risk factors differ from center to center, likely due to the wide variation in patient populations, donor source, and transplant preparation regimens. Third, MSOF is a consistent adverse risk factor for survival. An additional conclusion that can be drawn from the data presented in this article is that patients who do not show significant, objective improvement by the second week of PICU care are unlikely to survive. The limitation or withdrawal of life-sustaining medical support should be recommended to the patient, the patient's family, and the patient's doctors. Although there are no predictive models that are 100% reliable for these clinical situations, in the author's experience, most families and physicians view critical care support beyond 2 weeks, in the absence of clinical improvement, as futile care. It is clear that better data are needed in the form of prospective, multi-institutional studies that include the therapeutic efficacy of interventions such as high-frequency oscillatory ventilation, continuous venovenous hemodialysis, early use of noninvasive ventilation (ie, noninvasive positive pressure ventilation), the use of biologic agents to decrease inflammation, the impact of new antifungal medications, and lung-protective ventilation with permissive hypercapnia. Of these potential therapies, the author is aware of only one multi-institutional study involving continuous venovenous hemodialysis at this time.

In summary, most of the available data suggest that pediatric patients should be ventilated with low tidal volumes. The 6-mL/kg IBW tidal volume strategy as used in the ARDSNet studies is a reasonable target, having since been rigorously tested in several large, clinical trials (adult and pediatric). The mortality associated with ALI in these studies has never been lower, certainly supporting continued use of the 6 mL/kg target tidal volume as the "gold standard" and, thus, eliminating any equipoise in designing a pediatric trial comparing 6 mL/kg to a larger tidal volume. With mortality rates in children from ALI nearing 8% to 22% and with no clear surrogate outcomes identified to date, the sample sizes needed to show a significant clinical effect would be prohibitively large. Nonetheless, future research should compare 6 mL/kg IBW to even smaller tidal volumes or to high frequency ventilation in an attempt to further reduce the mortality associated with ALI and ARDS in the pediatric population.