Background: Pandemic influenza poses a serious threat to populations in low and lower-middle income countries that face delays in access to health care and inadequately equipped facilities. Oxygen is first-line therapy for influenza-related hypoxia and a standard component of emergency respiratory resuscitation, yet remains a scarce resource in many countries. Methodology: A snapshot survey of oxygen supply and associated infrastructure was performed at 231 health centres and hospitals in twelve African countries using the World Health Organization (WHO) Tool for Situational Analysis to Assess Emergency and Essential Surgical Care. WHO Global Initiative for Emergency and Essential Surgical Care, WHO regional and country offices, and local Ministries of Health facilitated data collection from facilities surveyed. Data was stored in the WHO DataCol SQL database and computerized spreadsheet tools were used to generate descriptive statistics. Results: Ninety-nine (43.8%) of facilities surveyed reported uninterrupted access to an oxygen source and 55 (24.6%) possessed a fully functioning oxygen concentrator. Electricity was fully available at only 81 (35.1%) health facilities. Conclusions: In addition to efforts to secure vaccines and antivirals, future global influenza preparedness efforts should include investments in oxygen and associated equipment and infrastructure at first referral health facilities, to minimize morbidity and mortality from influenza in regions with limited medical resources. Increasing oxygen delivery capacity in these areas may also provide long-term, post-pandemic benefits in the management of other medical conditions of significance, including trauma, neonatal pulmonary hypofunction, and HIV-related and childhood pneumonia.
In most rodents and some other mammals, the removal of one lung results in compensatory growth associated with dramatic angiogenesis and complete restoration of lung capacity. One pivotal mechanism in neoalveolarization is neovascularization, because without angiogenesis new alveoli can not be formed. The aim of this study is to image and analyze three-dimensionally the different patterns of neovascularization seen following pneumonectomy in mice on a sub-micron-scale. C57/BL6 mice underwent a left-sided pneumonectomy. Lungs were harvested at various timepoints after pneumonectomy. Volume analysis by microCT revealed a striking increase of 143 percent in the cardiac lobe 14 days after pneumonectomy. Analysis of microvascular corrosion casting demonstrated spatially heterogenous vascular densitities which were in line with the perivascular and subpleural compensatory growth pattern observed in anti-PCNA-stained lung sections. Within these regions an expansion of the vascular plexus with increased pillar formations and sprouting angiogenesis, originating both from pre-existing bronchial and pulmonary vessels was observed. Also, type II pneumocytes and alveolar macrophages were seen to participate actively in alveolar neo-angiogenesis after pneumonectomy. 3D-visualizations obtained by high-resolution synchrotron radiation X-ray tomographic microscopy showed the appearance of double-layered vessels and bud-like alveolar baskets as have already been described in normal lung development. Scanning electron microscopy data of microvascular architecture also revealed a replication of perialveolar vessel networks through septum formation as already seen in developmental alveolarization. In addition, the appearance of pillar formations and duplications on alveolar entrance ring vessels in mature alveoli are indicative of vascular remodeling. These findings indicate that sprouting and intussusceptive angiogenesis are pivotal mechanisms in adult lung alveolarization after pneumonectomy. Various forms of developmental neoalveolarization may also be considered to contribute in compensatory lung regeneration.Electronic supplementary materialThe online version of this article (doi:10.1007/s10456-013-9399-9) contains supplementary material, which is available to authorized users.
Respiratory muscle-associated stretch has been implicated in normal lung development (fetal breathing movements) and postpneumonectomy lung growth. To test the hypothesis that mechanical stretch from diaphragmatic contraction contributes to lung growth, we performed left phrenic nerve transections (PNT) in mice with and without ipsilateral pneumonectomy. PNT was demonstrated by asymmetric costal margin excursion and confirmed at autopsy. In mice with two lungs, PNT was associated with a decrease in ipsilateral lung volume (P<0.05) and lung weight (P<0.05). After pneumonectomy, PNT was not associated with a change in activity level, measureable hypoxemia, or altered minute ventilation; however, microCT scanning demonstrated altered displacement and underinflation of the cardiac lobe within the first week after pneumonectomy. Coincident with the altered structural realignment, lung impedance measurements, fitted to the constant-phase model, demonstrated elevated airway resistance (P<0.05), but normal peripheral tissue resistance (P>0.05). Most important, PNT appeared to abrogate compensatory lung growth after pneumonectomy; the weight of the lobes of the right lung was significantly less than pneumonectomy alone (P<0.001) and indistinguishable from nonsurgical controls (P>0.05). We conclude that the cyclic stretch associated with diaphragmatic muscle contraction is a controlling factor in postpneumonectomy compensatory lung growth.
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