Lung separation in children: Options and impact on gas exchange and lung compliance.

BACKGROUND: One-lung ventilation is a challenging airway technique in the pediatric population. Multiple airway devices can be employed, but there is no consensus as to the most reliable and physiologically advantageous method. This report is a review of the methods of one-lung ventilation in children in our practice, as well as an analysis of the impact of airway device type, patient age, and duration of lung separation on respiratory mechanics and gas exchange. METHODS: The records of all pediatric patients undergoing procedures requiring one-lung ventilation in a single center over an 18-month period were reviewed. Demographics, time required to achieve lung separation (anesthesia ready-time), and duration of one-lung ventilation were collected. Data from arterial blood gas analysis and ventilator parameters were collected at three time points: 15 minutes prior to one-lung ventilation (pre-OLV), 15 minutes after initiation of one-lung ventilation (during OLV), and 15 minutes after one-lung ventilation was ended (post-OLV). Standard equations for calculating compliance, the ratio of arterial partial pressure of oxygen to the fraction of inspired oxygen, and the alveolar-arterial oxygen gradient were used. RESULTS: Forty-six patients were identified with a mean age of 9.3 (inner quartile range 3-15) years. All patients had significant changes in pulmonary function when comparing pre-OLV with during OLV and when comparing during OLV with post-OLV. There were no significant changes from pre- to post-OLV. On further analysis, there were more pronounced changes in compliance and gas exchange in older patients (P = 0.003; 95% CI: -0.62 to -0.14). There was also a significant decrease in post-OLV compliance with a longer duration of OLV (P = 0.018; 95% CI: -0.02 to <-0.01). Airway device type did not have significant impact on the parameters examined. CONCLUSION: Our report demonstrates significant changes in lung function during one-lung ventilation. One particular device does not seem to be superior. Though pre-OLV measures of pulmonary function correlate closely with post-OLV, older age and a prolonged duration of one-lung ventilation did impact compliance.

Delayed resolution of lung inflammation in Il-1rn-/- mice reflects elevated IL-17A/granulocyte colony-stimulating factor expression.

IL-1 has been associated with acute lung injury (ALI) in both humans and animal models, but further investigation of the precise mechanisms involved is needed, and may identify novel therapeutic targets. To discover the IL-1 mediators essential to the initiation and resolution phases of acute lung inflammation, knockout mice (with targeted deletions for either the IL-1 receptor-1, i.e., Il-1r1(-/-), or the IL-1 receptor antagonist, i.e., Il-1rn(-/-)) were exposed to aerosolized LPS, and indices of lung and systemic inflammation were examined over the subsequent 48 hours. The resultant cell counts, histology, protein, and RNA expression of key cytokines were measured. Il-1r1(-/-) mice exhibited decreased neutrophil influx, particularly at 4 and 48 hours after exposure to LPS, as well as reduced bronchoalveolar lavage (BAL) expression of chemokines and granulocyte colony-stimulating factor (G-CSF). On the contrary, Il-1rn(-/-) mice demonstrated increased BAL neutrophil counts, increased BAL total protein, and greater evidence of histologic injury, all most notably 2 days after LPS exposure. Il-1rn(-/-) mice also exhibited higher peripheral neutrophil counts and greater numbers of granulocyte receptor-1 cells in their bone marrow, potentially reflecting their elevated plasma G-CSF concentrations. Furthermore, IL-17A expression was increased in the BAL and lungs of Il-1rn(-/-) mice after exposure to LPS, likely because of increased numbers of γδ T cells in the Il-1rn(-/-) lungs. Blockade with IL-17A monoclonal antibody before LPS exposure decreased the resultant BAL neutrophil counts and lung G-CSF expression in Il-1rn(-/-) mice, 48 hours after exposure to LPS. In conclusion, Il-1rn(-/-) mice exhibit delayed resolution in acute lung inflammation after exposure to LPS, a process that appears to be mediated via the G-CSF/IL-17A axis.

Spinal Cord Stimulation for Neurogenic Thoracic Outlet Syndrome: A Case Report.

Despite conservative and surgical treatments, patients with neurogenic thoracic outlet syndrome can develop debilitating chronic pain of the shoulder and arm. Here we report a case of a patient who failed medical treatment, surgical resection of the first rib, and subsequent resection of rib regrowth with partial excision of a hypertrophied middle scalene muscle. Ultimately, this patient was successfully treated with spinal cord stimulation with dramatic pain relief and remarkable functional improvement for more than 3 years. This first report provides hope for those who suffer from this debilitating syndrome.