The future of respiratory care.

The term respiratory care has more than one meaning, referring both to a subject area within clinical medicine and to a distinct health care profession. In the light of several fundamental transformations of health care during the 20th century, this article reviews the history of respiratory care in both of these contexts and offers 10 predictions for the future: (1) Less focus on raising P(aO2) as a primary goal in managing patients with acute hypoxemic respiratory failure. (2) More attention to the adequacy of tissue oxygenation in such patients, irrespective of P(aO2), and the emergence of "permissive hypoxemia," analogous to permissive hypercapnia, in managing them. (3) Smarter monitors that display information less but process it more, while interacting directly with ventilators and other devices to modify therapeutic interventions. (4) Increased use of and expertise with noninvasive ventilation, with a corresponding decrease in intubations and complications, in treating patients with acute exacerbations of COPD. (5) Increased use of triage in the intensive care unit, including earlier determination of the appropriateness of maximal supportive intervention. (6) Greater use of protocols in patient assessment and management, in all clinical settings. (7) Increased awareness of, expertise in, and resources for palliative care, with a more active and acknowledged role for respiratory therapists. (8) Accelerating progress in smoking cessation and prevention, and also in early detection and intervention in COPD, led by the respiratory care profession. (9) An increasing presence and impact of respiratory therapists as coordinators and care givers in home care. (10) A continued and enlarging role for the journal Respiratory Care in disseminating research findings, clinical practice guidelines, protocols, and practical educational materials in all areas of the field.

Trauma critical care.

The surgical approach to the most injured patients has changed in recent years. Many patients arrive in the intensive care unit with problems that in the past would have been definitively addressed in the operating room, or led to the patient's demise due to continued attempts to complete all surgical procedures, despite deteriorating physiology. As a result, the triad of hypothermia, acidosis, and coagulopathy, along with the frequent complication of abdominal compartment syndrome, are critical factors that require correction in the intensive care unit. Prompt correction is necessary not only to allow expeditious completion of required surgical procedures, but because this triad, unless interrupted, invariably leads to death during resuscitation.

Persistent air leaks in patients receiving mechanical ventilation.

The term bronchopleural fistula (BPF) can be loosely defined as persistent leakage of gas from the airways into the pleural space. A true BPF, however, is located in the central airways, whereas leaks located peripherally are better described by the term parenchymal-pleural fistula (PPF). The presence of a persistent leak in a mechanically ventilated patient is a worrisome prognostic sign independent of the precise origin, yet it is important to distinguish BPF from PPF in this population. Fundamental differences in the pathogenesis and natural history of these two entities dictate divergent approaches to management. This review compares and contrasts the evaluation and management of BPF and PPF in patients receiving mechanical ventilation, and provides an overview of the many nonsurgical interventions used to manage persistent leaks.

Implications of extubation delay in brain-injured patients meeting standard weaning criteria.

We hypothesized that variation in extubating brain injured patients would affect the incidence of nosocomial pneumonia, length of stay, and hospital charges. In a prospective cohort of consecutive, intubated brain-injured patients, we evaluated daily: intubation status, spontaneous ventilatory parameters, gas exchange, neurologic status, and specific outcomes listed above. Of 136 patients, 99 (73%) were extubated within 48 h of meeting defined readiness criteria. The other 37 patients (27%) remained intubated for a median 3 d (range, 2 to 19). Patients with delayed extubation developed more pneumonias (38 versus 21%, p < 0.05) and had longer intensive care unit (median, 8.6 versus 3.8 d; p < 0.001) and hospital (median, 19.9 versus 13.2 d; p = 0.009) stays. Practice variation existed after stratifying for differences in Glasgow Coma Scale scores (10 versus 7, p < 0.001) at time of meeting readiness criteria, particularly for comatose patients. There was a similar reintubation rate. Median hospital charges were $29,057.00 higher for extubation delay patients (p < 0.001). This study does not support delaying extubating patients when impaired neurologic status is the only concern prolonging intubation. A randomized trial of extubation at the time brain-injured patients fulfill standard weaning criteria is justifiable.

Pathophysiology and clinical effects of chronic hypoxia.

Hypoxia exists when there is a reduced amount of oxygen in the tissues of the body. Hypoxemia refers to a reduction in PO2 below the normal range, regardless of whether gas exchange is impaired in the lung, CaO2 is adequate, or tissue hypoxia exists. There are several potential physiologic mechanisms for hypoxemia, but in patients with COPD the predominant one is V/Q mismatching, with or without alveolar hypoventilation, as indicated by PaCO2. Hypoxemia caused by V/Q mismatching as seen in COPD is relatively easy to correct, so that only comparatively small amounts of supplemental oxygen (less than 3 L/min for the majority of patients) are required for LTOT. Although hypoxemia normally stimulates ventilation and produces dyspnea, these phenomena and the other symptoms and signs of hypoxia are sufficiently variable in patients with COPD as to be of limited value in patient assessment. Chronic alveolar hypoxia is the main factor leading to development of cor pulmonale--right ventricular hypertrophy with or without overt right ventricular failure--in patients with COPD. Pulmonary hypertension adversely affects survival in COPD, to an extent that parallels the degree to which resting mean pulmonary artery pressure is elevated. Although the severity of airflow obstruction as measured by FEV1 is the best correlate with overall prognosis in patients with COPD, chronic hypoxemia increases mortality and morbidity for any severity of disease. Large-scale studies of LTOT in patients with COPD have demonstrated a dose-response relationship between daily hours of oxygen use and survival. There is reason to believe that continuous, 24-hours-per-day oxygen use in appropriately selected patients would produce a survival benefit even greater than that shown in the NOTT and MRC studies.

Mechanisms of hypoxemia.

The definitions of hypoxemia and hypoxia, and basic pulmonary anatomy and oxygen delivery are reviewed. Low ambient oxygen, hypoventilation, ventilation-perfusion mismatch, and right-to-left shunt, the four basic mechanisms of hypoxemia are described in detail with patient examples. For the sake of completion, a fifth mechanism of hypoxemia that is rarely seen in human disease is described. Because getting oxygen into the blood stream is only half the story, mechanisms of tissue hypoxia in the setting of adequate oxygen exchange from the lungs to the blood are discussed. An algorithm is proposed for diagnosing patients who present with hypoxia.

Complications of mechanical ventilation. A bedside approach.

Instead of cataloging complications reported to occur during mechanical ventilation, the authors have discussed the potential causes for several common scenarios in the management of ventilated patients. These include the new development of hypotension, acute respiratory distress (fighting the ventilator), repeated sounding of the ventilator's high-pressure alarm, hypoxemia, blood from the endotracheal tube, and the problem of diagnosing VAP. In the course of considering likely explanations for this group of circumstances for which the clinician is consulted or called to the bedside, virtually all reported ventilator-associated complications must be discussed. This new approach to an important aspect of ICU care may aid in clinical problem-solving and reduce the likelihood that a diagnosis will be missed or inappropriate measures taken in the absence of a systematic, pathophysiology-based approach.

Interruption of oxygen therapy during intrahospital transport of non-ICU patients: elimination of a common problem through caregiver education.

UNLABELLED: Hospital inpatients frequently leave their rooms for diagnostic procedures and for other reasons. For some, interruption of oxygen therapy during transport could lead to serious complications. In our institution, non-ICU patient transport is done mainly by nonclinical personnel from an independent transport service. MATERIALS & METHODS: We reviewed respiratory care department and transport service records for 5 arbitrarily selected days to determine the number of non-ICU patients receiving O2 therapy, the number of times these patients were transported, and the number of occasions on which O2 was used during the transport. We then interviewed the primary nurse for each patient transported without O2 and reviewed the charts of those patients to determine whether this practice was consistent with the therapy as it had been ordered. After our initial investigation showed a high rate of transport without prescribed O2, we sent memoranda to all nursing units describing proper procedures for transport of patients for whom O2 had been ordered. We then repeated the audit. Because the second audit showed the need, we conducted education sessions with all nursing personnel on the affected units and posted guidelines for O2 use during transport. A third audit was then conducted. In addition, we performed a telephone survey of respiratory care department managers to learn the patient-transport practices in all hospitals in our state with more than 200 beds, using a structured questionnaire. RESULTS: During the initial 125 patient-days of O2 therapy, O2 accompanied patients on only 30 of 55 transports (55%). After distribution of memoranda, O2 use increased to 28 of 35 transports (80%) during 82 patient-days. The second educational effort resulted in O2 use with all 35 transports (100%) performed during 99 patient-days. Survey results from 24 hospitals with 225-680 beds showed that 11 (46%) had separate transport services and that decisions on O2 use during patient transport were generally made by nursing staff. Although respiratory care departments supplied the O2 equipment, their personnel were involved in non-ICU transports in only 5/24 hospitals. CONCLUSIONS: Patients receiving O2 therapy on acute-care wards are often transported to other areas of the hospital without O2. This potentially dangerous practice can be corrected by respiratory care practitioners through educational efforts targeted toward those responsible for administering O2 therapy in non-ICU hospital areas.

Pneumothorax and barotrauma.

This article discusses pneumothorax and barotrauma from the viewpoints of both the intensivist/pulmonologist and the emergency room physician because both groups of clinicians frequently encounter these potentially life-threatening conditions. The discussion focuses primarily on pneumothorax and barotrauma as they occur in adults rather than in neonates and children.