Biomedical subjects

C Rylander

Publications and source records attributed to C Rylander.

5 recordsLinked to original sources

PubMed2004

Oleic acid lung injury: a morphometric analysis using computed tomography.

BACKGROUND: The oleic acid-induced lung injury (OAI) model is considered to represent the early phase of acute respiratory distress syndrome (ARDS). Its inherent properties are important for the design and the interpretation of interventional studies. The aim of this study was to describe the evolution of morphometric lung changes during OAI using computed tomography (CT) analysis. Furthermore, the effect of a temporary change in positive end-expiratory pressure (PEEP) was evaluated. METHODS: Fifteen anaesthetized pigs were ventilated in volume-controlled mode with a baseline PEEP of 5 cm H(2)O. Helical CT scans were taken at baseline and 1 h after oleic acid injection. The PEEP was then either increased to 10 cm H(2)O (n = 5), decreased to 0 cm H(2)O (n = 5) or kept constant (n = 5) for 30 min. For the next 30 min, the baseline PEEP level was applied in all animals before the final CT scans 2 h after the induction of OAI. Dimensional and volumetric changes were determined from radiographical attenuation values. RESULTS: There was a major decrease in gas volume and an increase in tissue volume within the first hour. A net increase in total lung volume, with a larger transverse area but no displacement of the diaphragm, was manifest after 2 h. A minor increase in volume of non-aerated lung, located to the caudal region, was observed during the second hour. The tidal volume was redistributed to the middle and apical regions. The temporary change in PEEP did not influence the morphological progress of OAI. CONCLUSION: Decreased gas volume and increased tissue volume are the dominating morphometric characteristics of oleic acid lung injury, occurring mainly within the first hour. With these changes manifest, the course of injury is not affected by a limited period of moderately changed PEEP during the second hour. The net increase of total lung volume suggests a predominance of oedema formation over airway and alveolar collapse.

Animals↗

PubMed2001

Assessment of respiratory system mechanics by artificial neural networks: an exploratory study.

We evaluated 1) the performance of an artificial neural network (ANN)-based technology in assessing the respiratory system resistance (Rrs) and compliance (Crs) in a porcine model of acute lung injury and 2) the possibility of using, for ANN training, signals coming from an electrical analog (EA) of the lung. Two differently experienced ANNs were compared. One ANN (ANN(BIO)) was trained on tracings recorded at different time points after the administration of oleic acid in 10 anesthetized and paralyzed pigs during constant-flow mechanical ventilation. A second ANN (ANN(MOD)) was trained on EA simulations. Both ANNs were evaluated prospectively on data coming from four different pigs. Linear regression between ANN output and manually computed mechanics showed a regression coefficient (R) of 0.98 for both ANNs in assessing Crs. On Rrs, ANN(BIO) showed a performance expressed by R = 0.40 and ANN(MOD) by R = 0.61. These results suggest that ANNs can learn to assess the respiratory system mechanics during mechanical ventilation but that the assessment of resistance and compliance by ANNs may require different approaches.

Animals↗

PubMed2000

The impact of respiratory variables on mortality in non-ARDS and ARDS patients requiring mechanical ventilation.

OBJECTIVES: Primarily, to determine if respiratory variables, assessed on a daily basis on days 1-6 after ICU admission, were associated with mortality in non-ARDS and ARDS patients with respiratory failure requiring mechanical ventilation. Secondarily, to determine non-respiratory factors associated with mortality in ARDS and non-ARDS patients. DESIGN: Prospective multicentre clinical study. SETTING: Seventy-eight intensive care units in Sweden and Iceland. PATIENTS: Five hundred twenty non-ARDS and 95 ARDS patients. MEASUREMENTS AND RESULTS: Potentially prognostic factors present at inclusion were tested against 90-day mortality using a Cox regression model. Respiratory variables (PaO2/FIO2, PEEP, mean airway pressure (MAP) and base excess (BE)) were tested against mortality using the model. Primary aim: in non-ARDS a low PaO2/FIO2 on day 1, RR (risk ratio) = 1.17, CI (95% confidence interval) (1.00; 1.36), day 4, 1.24 (1.02; 1.50), day 5, 1.25 (1.02; 1.53) and a low MAP at baseline, 1.18 (1.00; 1.39), day 2, 1.24 (1.02; 1.52), day 3, 1.33 (1.06; 1.67), day 6, 2.38 (1.11; 5.73) were significantly associated with 90-day death. Secondary aim: in non-ARDS a low age, RR = 0.77 (0.67; 0.89), female gender, 0.85 (0.74; 0.98), and low APS (acute physiologic score), 0.85 (0.73; 0.99), were associated with survival; chronic disease, 1.31 (1.12; 1.52), and non-pulmonary origin to the respiratory failure, 1.27 (1.10; 1.47), with death. In ARDS low age, RR = 0.65 CI (0.46; 0.91), and low APS, 0.65 (0.46; 0.90), were associated with survival. CONCLUSIONS: No independent significant association was seen between 90-day mortality and degree of hypoxaemia, PEEP, MAP or BE for the first full week of ICU care in either ARDS or non-ARDS. In a sub-group of non-ARDS a lower PaO2/FIO2 and MAP tended to influence mortality where a significant association was seen for 3 of 7 study days. Age, gender, APS, presence of a chronic disease and a pulmonary/non-pulmonary reason for the respiratory failure were associated with mortality in non-ARDS, while only age and APS showed a similar association in ARDS.

APACHE↗

PubMed1981

Ro 11-1430, a new retinoic acid derivative for the topical treatment of acne.

The clinical efficacy and tolerance of a new retinoic acid derivative, Ro 11-1430, in the treatment of acne vulgaris have been compared with those of tretinoin in a double-blind trial with 60 patients during 8 weeks. The efficacy of both drugs was good. Tretinoin showed a tendency to give better effect but this was not statistically significant. However, tolerance of the new derivative was better. 48 of the patients were treated with Ro 11-1430 for another 3 months with good effect and tolerance. In a long-term study, 32 patients with previous irritation of tretinoin have been treated with Ro 11-1430 between 1.5 and 17 months with good tolerance.

Acne Vulgaris↗

PubMed1978

A clinical and bacteriological evaluation of the effect of sulphamethoxazole-trimethoprim in acne vulgaris, resistant to prior therapy with tetracyclines.

42 patients with acne vulgaris, clinically resistant to prior therapy with tetracyclines, were evaluated after therapy with sulphamethoxazole-trimethoprim (400 + 80 mg) twice daily. Initially and after 6, 12 and 18 weeks of treatment in each patient the different acne lesions were counted and pus specimens from unhealed pustules were taken for bacteriological analysis. Complete remission or excellent results were obtained in 33 patients (79%) at the end of treatment despite a relative increase of Staphylococcus hominis and Propionibacterium granulosum. These species were more resistant in agar dilution test to the combination sulphamethoxazole-trimethoprim (20:1) than other isolated species.

Acne Vulgaris↗