American journal of respiratory and critical care medicine
-
Am. J. Respir. Crit. Care Med. · Aug 1997
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialExtubation outcome after spontaneous breathing trials with T-tube or pressure support ventilation. The Spanish Lung Failure Collaborative Group.
A 2-h T-tube trial of spontaneous breathing was used in selecting patients ready for extubation and discontinuation of mechanical ventilation. However, some doubt remains as to whether it is the most appropriate method of performing a spontaneous breathing trial. We carried out a prospective, randomized, multicenter study involving patients who had received mechanical ventilation for more than 48 h and who were considered by their physicians to be ready for weaning according to clinical criteria and standard weaning parameters. ⋯ Clinical evolution during the trial was not different in patients reintubated and successfully extubated. ICU mortality among reintubated patients was significantly higher than in successfully extubated patients (27 versus 2.6%, p < 0.001). Spontaneous breathing trials with pressure support or T-tube are suitable methods for successful discontinuation of ventilator support in patients without problems to resume spontaneous breathing.
-
Am. J. Respir. Crit. Care Med. · Aug 1997
Comparative StudySignificance of the isolation of Candida species from respiratory samples in critically ill, non-neutropenic patients. An immediate postmortem histologic study.
The diagnosis of pulmonary candidiasis is still controversial. We undertook a prospective study on 25 non-neutropenic, mechanically ventilated (> 72 h) patients who died in our ICU with the aim of assessing the incidence and significance of the isolation of Candida species from quantitative cultures of immediate postmortem lung biopsies and different respiratory sampling techniques. Immediate postmortem respiratory samples (endotracheal aspirate, protected specimen brush [PSB], bronchoalveolar lavage [BAL], blind biopsies [average 14/patient], and bilateral bronchoscopically guided biopsies [two per patient]) were taken from all patients. ⋯ The incidence of Candida isolation from pulmonary biopsies in critically ill mechanically ventilated, non-neutropenic patients who die is high (40%). However, the incidence of definite Candida pneumonia was 8%. We also found that Candida colonization is uniform throughout the different lung regions, and that the presence of Candida in respiratory samples, independently of quantitative cultures, is not a good marker of Candida pneumonia in critically ill, non-neutropenic, non-AIDS patients.
-
Am. J. Respir. Crit. Care Med. · Aug 1997
D-dimer testing for suspected pulmonary embolism in outpatients.
The plasma level of D-dimer, a fibrin degradation product (FDP), is nearly always increased in the presence of acute pulmonary embolism (PE). Hence, a normal D-dimer level (below a cutoff value of 500 micrograms/L by enzyme-linked immunosorbent assay [ELISA]) may allow the exclusion of PE. To assess the negative predictive value of a D-dimer concentration below 500 micrograms/L in outpatients with suspected PE, and the safety of withholding anticoagulant treatment from such patients, we performed D-dimer assays, lower limb venous compression ultrasonography, and lung scans in 671 consecutive outpatients presenting in the Emergency Center of the Geneva University Hospital with suspected PE. ⋯ Using a cutoff value of 4,000 micrograms/L, the overall specificity of D-dimer concentration for PE was 93.1%. In conclusion, a plasma D-dimer concentration below 500 micrograms/L allows the exclusion of PE in 29% of outpatients suspected of having PE. Withholding anticoagulation from such patients is associated with a conservative 1% risk of thromboembolic events during follow-up.
-
Am. J. Respir. Crit. Care Med. · Aug 1997
Expression of mRNA for gastrin-releasing peptide receptor by human bronchial epithelial cells. Association with prolonged tobacco exposure and responsiveness to bombesin-like peptides.
Bombesin-like peptides (BLPs) are important regulators of lung development and may also act as autocrine growth factors in lung tumors. We have previously demonstrated expression of mRNA for the three BLP receptor subtypes (neuromedin B [NMB]) receptor, gastrin-releasing peptide [GRP] receptor, and bombesin receptor subtype 3 [BRS-3]) in human non-small cell lung carcinoma (NSCLC) cell lines and bronchial biopsies using the reverse transcription-polymerase chain reaction (RT-PCR; DeMichele, et al. Am. ⋯ Cultures of HBE cells from four of the five subjects with severe obstructive lung disease gave a positive response to GRP and NMB in proliferation assays, compared to five of fifteen without severe obstructive lung disease, but this difference was not significant (p = 0.13). These results suggest there is an increased likelihood of expression of the GRP receptor mRNA in the respiratory epithelium of some individuals with a history of prolonged tobacco exposure, and that expression of the GRP receptor mRNA is accompanied by responsiveness to the mitogenic effects of BLPs. These effects appear to persist after smoking cessation.
-
Am. J. Respir. Crit. Care Med. · Aug 1997
Lactoferrin, a potent tryptase inhibitor, abolishes late-phase airway responses in allergic sheep.
Tryptase, a serine protease released exclusively from activated mast cells, has been implicated as a potential causative agent in asthma. Enzymatically active tryptase is comprised of four subunits, and heparin stabilizes the associated tetramer. ⋯ Lactoferrin was tested in an allergic sheep model of asthma; aerosolized lactoferrin (10 mg in 3 ml phosphate-buffered saline, 0.5 h before as well as 4 and 24 h after inhalation challenge by Ascaris suum) abolished both late-phase bronchoconstriction (no significant increase in specific lung resistance 4 to 8 h following provocation, p < 0.05 versus vehicle treatment) and airway hyperresponsiveness (no detectable increase in airway sensitivity to carbachol challenge 24 h after antigen challenge, p < 0.05 versus vehicle). These data suggest tryptase involvement in both late-phase bronchoconstriction and airway hyperreactivity and furthermore suggest that a physiological function of neutrophil lactoferrin is the inhibition of tryptase released from mast cells.