American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Aug 1995
Comparative StudyShould mechanical ventilation be optimized to blood gases, lung mechanics, or thoracic CT scan?
This study was aimed at providing data for optimization of mechanical ventilation in patients with acute respiratory distress syndrome (ARDS). The effects of ventilation with positive end-expiratory pressure (PEEP) titrated to blood gases were studied by thoracic computed tomographic (CT) scans and lung mechanics measurements in eight patients. CT density histograms at end-expiration were used to investigate the effects of PEEP on three differently aerated zones. ⋯ With regard to plateau pressures, only one patient was ventilated above the deflection point. However, monitoring of volumes showed that these four patients had an end-inspiratory volume above this point. We conclude that mechanical ventilation may be initially adjusted on the basis of blood gas values and then optimized on the basis of lung mechanics to limit the risk of baro-volotrauma.
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Am. J. Respir. Crit. Care Med. · Aug 1995
Multicenter Study Comparative StudyPulmonary function tests in HIV-infected patients without AIDS. Pulmonary Complications of HIV Infection Study Group.
To determine the prevalence, incidence, and types of lung diseases that occur in association with HIV infection, 1,353 subjects, including HIV-seropositive homosexual men, injection drug users, female sexual partners of HIV-positive men, and HIV-seronegative control subjects from the first two transmission categories were evaluated prospectively in a multicenter study. Patients with AIDS at the time of initial evaluation were excluded. One thousand two-hundred ninety-four subjects who had no AIDS-defining diagnosis within 3 mo of enrollment had measurements of FVC, FEV1 and DLCO at the time of enrollment. ⋯ Part of the reduction in DLCO in drug users was attributable to factors other than HIV infection, especially cigarette smoking and race. Using predicted values that take cigarette smoking into account, the prevalence of abnormality in DLCO was higher among injection drug users (33.3%) than among homosexual men (11.2%) and female sexual partners (12.7%). These results show that advanced HIV infection, characterized by CD4 count < 200/mm3 or HIV-associated symptoms, and factors unrelated to HIV infection, including race, cigarette smoking, and injection drug use, are all associated with reductions in DLCO measurements.
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Am. J. Respir. Crit. Care Med. · Aug 1995
Efficacy of expiratory tracheal gas insufflation in a canine model of lung injury.
Tracheal gas insufflation (TGI) improves the efficiency of CO2 elimination by reducing the CO2-laden dead space of the airways. The effect of TGI on PaCO2 diminishes in the setting of acute lung injury (ALI) because an increased alveolar component dominates the total physiologic dead space. Nevertheless, adopting a strategy of permissive hypercapnia should partially offset the decreased efficacy of TGI by increasing CO2 concentration in the proximal airways. ⋯ The corresponding decrements in PaCO2 produced by TGI at a flow rate of 10 L/min were 16 +/- 3, 24 +/- 10, and 10 +/- 2 mm Hg, respectively. TGI decreased total physiologic dead space per breath (VD) by 56, 31, and 28 ml during the pre-OAI, post-OAI, and post-OA/VT stages, respectively. Despite a smaller reduction in VD during the post-OAI stage, the effect of TGI on PaCO2 was preserved because of the relatively high PaCO2 prior to its initiation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Am. J. Respir. Crit. Care Med. · Aug 1995
Effects of an antibody to interleukin-5 in a monkey model of asthma.
To investigate the role of interleukin-5 (IL-5) on airway hyperreactivity and pulmonary inflammation in nonhuman primate airways, the effect of a neutralizing monoclonal antibody to murine IL-5 (TRFK-5) was investigated in a cynomolgus monkey model of allergic asthma. Anesthetized Ascaris-sensitive monkeys underwent bronchoalveolar lavage (BAL) to assess the granulocyte content of this fluid before and 24 h after aerosolized Ascaris suum extract inhalation. Airway reactivity was assessed by the concentration of inhaled histamine required to produce a 40% reduction in dynamic lung compliance (Cdyn40). ⋯ In contrast, only small nonsignificant changes in airway reactivity and granulocyte influx into the BAL occurred after aerosolized saline as a sham challenge. When the monkeys were treated 1 h before Ascaris challenge with the TRFK-5 antibody (0.3 mg/kg, intravenously), there was no increase in airway reactivity after Ascaris challenge (Cdyn40 = 0.032 +/- 0.016% before Ascaris; Cdyn40 = 0.217 +/- 0.196% after Ascaris) and there were only small increases in the number of eosinophils and neutrophils in the BAL after Ascaris challenge. The inhibition of this pulmonary eosinophilia and bronchial hyperresponsiveness by TRFK-5 was seen for up to 3 mo after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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Am. J. Respir. Crit. Care Med. · Aug 1995
Randomized Controlled Trial Comparative Study Clinical TrialA randomized, double-blind comparison of methoxamine and epinephrine in human cardiopulmonary arrest.
The beneficial effect of epinephrine has been attributed to its alpha-adrenergic properties. The present study was designed to compare the effects of epinephrine and methoxamine in witnessed cardiac arrests. Consecutive, witnessed cardiac-arrest victims presenting to the emergency room or from the inpatient population of our institution were enrolled in this study. ⋯ Of the 145 patients remaining, 77 received methoxamine (M) and 68 epinephrine (E). There was no difference in rate of successful resuscitation (42% versus 53%, M versus E, respectively), or in neurologic outcome as measured by the Glasgow-Pittsburgh Coma Score (GPCS). This study failed to demonstrate any difference in the rate of initial resuscitation, survival to discharge from the hospital, or neurologic status with methoxamine as opposed to epinephrine in the setting of cardiac arrest.