Current aspects of acute respiratory distress syndrome in children

Acute respiratory distress syndrome (ARDS) is a frequent condition in pediatric intensive care units. The mortality remains high despite advances in conventional mechanical ventilation and aetiological treatment. Several animal studies have documented lung injury during mechanical ventilation with high tidal volume, and clinical investigations have shown that in human ARDS, most ventilation is distributed to the small areas of remaining aerated lung resulting in overdistension of these areas and lung injury ("baby lung" theory). Nevertheless the usefulness of extrapulmonary gas exchange remains much debated. New ventilatory strategies have been developed in order to reduce ventilator-induced lung injury and to improve systemic oxygenation but multicentric randomized clinical trials are needed before these strategies can be validated.     

Open-lung biopsy in patients with acute respiratory distress syndrome

Occupational exposures contribute to the morbidity and mortality of many diseases. However, occupational diseases continue to be underrecognized even though they are responsible for an estimated 860,000 illnesses and 60,300 deaths each year. Family physicians can play an important role in improving the recognition of occupational disease, preventing progressive illness and disability in their own patients, and contributing to the protection of other workers similarly exposed. This role can be maximized if physicians raise their level of suspicion for workplace disease, develop skills in taking occupational histories and establish routine access to occupational health resources.     

Acute respiratory distress syndrome in children

In 1991, the Dental Implant Clinical Research Group initiated a long-term clinical study in cooperation with the Department of Veterans Affairs to investigate the influence of implant design, application, and site of placement on clinical performance and crestal bone height. As part of this investigation, Periotest values for 2,212 root from implants were determined at second-stage surgery and during a 24-month follow-up period. Mean Periotest values decreased for implants placed in quality 1 and 2 bone, did not change for implants in quality 3 bone, and increased for implants in quality 4 bone. Implants in the posterior maxilla and single implants in the anterior maxilla had increasing mean Periotest values as compared with decreasing values for implants in other regions. Mean Periotest values for uncoated implants decreased gradually to approach those of hydroxyapatite-coated implants.     

Patients with acute respiratory distress syndrome mechanically ventilated in prone position

Animal experiments and human studies have shown better oxygenation in mechanically ventilated patients with ARDS when the patient is situated in the prone position. In contradiction to former theories of a gravitational gradient of lung perfusion, a number of investigators have found that lung perfusion is preferentially distributed to the dorsal lung regions regardless of body position. The basal atelectasis and oedema in ARDS are resolved and only partly distributed anteriorly in the prone position, and these areas are thereby better ventilated. The combination of better ventilation and unchanged perfusion improves the ventilation/perfusion ratio and decreases the shunt in the prone position. In two cases of prone position in mechanically ventilated patients the PaO2/FiO2 ratio increased from 7.5 to 14.3 and from 8.8 to 19.8 after one hour in the prone position, and some of the improvement was permanent. Prone position has only minor side effects and is recommended as the first choice amongst adjunct therapies in mechanical ventilation in patients with ARDS remaining hypoxic in conventional therapy in the supine position.     

The biological properties of Haemophilus influenza isolated from healthy children and from patients with acute and chronic respiratory diseases

The comparative study of the biological properties of H. influenzae strains isolated from healthy children and from patients with acute and chronic respiratory diseases has been made, taking into account the biochemical features (biotypes) and adhesive activity of these strains. Differences in various biotypes of H. influenzae strains isolated from patients with bronchopulmonary diseases and from healthy carriers have been established. H. influenzae strains isolated from various sources differ by their adhesive properties: strains isolated from patients with acute bronchopulmonary diseases have the highest adhesive activity, while strains isolated from healthy controls have the lowest adhesive activity. The data thus obtained indicate the possible dependence of the degree and duration of the colonization of the respiratory tract by H. influenzae on the biological properties of these microorganisms. The monitoring of the sensitivity of H. influenzae strains to antibiotics has demonstrated that these strains retain high sensitivity to ampicillin, chloramphenicol, gentamicin and exhibit a tendency towards an increase in resistance to penicillin and erythromycin.     

Improved oxygenation utilizing a prone positioner in patients with acute respiratory distress syndrome

OBJECTIVES: (a) To determine whether placing patients with acute respiratory distress syndrome in the prone position by a light-weight portable support frame improves oxygenation, (b) whether one can determine which patients benefit from prone positioning, and (c) to determine an effective technique for prone positioning of patients. DESIGN: Prospective, controlled trial without blinding. SETTING: Medical intensive care units in two urban university-affiliated hospitals. PATIENTS: Fifteen patients meeting a standard definition for acute respiratory distress syndrome were studied prospectively. Each patient acted as his own control for purposes of comparison. INTERVENTION: Patients were assigned randomly to begin in either supine or prone positions. The positioning frame was used to turn patients from one position to the other, and oxygenation, ventilation, respiratory mechanics, and hemodynamics were measured. RESULTS: Significantly better oxygenation was seen in the prone positions than in the supine (P < 0.05). In the overall population there was a decrease in AaDO2 of 21 mmHg when the patients were placed prone. The groups were then divided into responders (n = 9) and nonresponders (n = 6). There were significant differences between the groups (but not between positions) regarding PaO2, baseline, PaCO2, pulmonary artery pressures, and peak inspiratory pressures on the ventilator and in ICU length of stay and time on mechanical ventilatory support. CONCLUSION: Prone positioning improves oxygenation in the majority of patients studied and can be achieved relatively easily.     

Permissive hypercapnia with and without expiratory washout in patients with severe acute respiratory distress syndrome

BACKGROUND: Permissive hypercapnia is a ventilatory strategy aimed at avoiding lung volutrauma in patients with severe acute respiratory distress syndrome (ARDS). Expiratory washout (EWO) is a modality of tracheal gas insufflation that enhances carbon dioxide removal during mechanical ventilation by reducing dead space. The goal of this prospective study was to determine the efficacy of EWO in reducing the partial pressure of carbon dioxide (PaCO2) in patients with severe ARDS treated using permissive hypercapnia. METHODS: Seven critically ill patients with severe ARDS (lung injury severity score, 3.1 +/- 0.3) and no contraindications for permissive hypercapnia were studied. On the first day, hemodynamic and respiratory parameters were measured and the extent of lung hyperdensities was assessed using computed tomography. A positive end-expiratory pressure equal to the opening pressure identified on the pressure-volume curve was applied. Tidal volume was reduced until a plateau airway pressure of 25 cm H2O was reached. On the second day, after implementation of permissive hypercapnia, EWO was instituted at a flow of 15 l/min administered during the entire expiratory phase into the trachea through the proximal channel of an endotracheal tube using a ventilator equipped with a special flow generator. Cardiorespiratory parameters were studied under three conditions: permissive hypercapnia, permissive hypercapnia with EWO, and permissive hypercapnia. RESULTS: During permissive hypercapnia, EWO decreased PaCO2 from 76 +/- 4 mmHg to 53 +/- 3 mmHg (-30%; P < 0.0001), increased pH from 7.20 +/- 0.03 to 7.34 +/- 0.04 (P < 0.0001), and increased PaO2 from 205 +/- 28 to 296 +/- 38 mmHg (P < 0.05). The reduction in PaCO2 was accompanied by an increase in end-inspiratory plateau pressure from 26 +/- 1 to 32 +/- 2 cm H2O (P = 0.001). Expiratory washout also decreased cardiac index from 4.6 +/- 0.4 to 3.7 +/- 0.3 l.min-1.m-2 (P < 0.01), mean pulmonary arterial pressure from 28 +/- 2 to 25 +/- 2 mmHg (P < 0.01), and true pulmonary shunt from 47 +/- 2 to 36 +/- 3% (P < 0.01). CONCLUSIONS: Expiratory washout is an effective and easy-to-use ventilatory modality to reduce PaCO2 and increase pH during permissive hypercapnia. However, it significantly increases airway pressures and lung volume through expiratory flow limitation, reexposing some patients to a risk of lung volutrauma if the extrinsic positive end-expiratory pressure is not substantially reduced.