Lung Volume, Breathing Pattern and Ventilation Inhomogeneity in Preterm and Term Infants

BACKGROUND: Morphological changes in preterm infants with bronchopulmonary dysplasia (BPD) have functional consequences on lung volume, ventilation inhomogeneity and respiratory mechanics. Although some studies have shown lower lung volumes and increased ventilation inhomogeneity in BPD infants, conflicting results exist possibly due to differences in sedation and measurement techniques. METHODOLOGY/PRINCIPAL FINDINGS: We studied 127 infants with BPD, 58 preterm infants without BPD and 239 healthy term-born infants, at a matched post-conceptional age of 44 weeks during quiet natural sleep according to ATS/ERS standards. Lung function parameters measured were functional residual capacity (FRC) and ventilation inhomogeneity by multiple breath washout as well as tidal breathing parameters. Preterm infants with BPD had only marginally lower FRC (21.4 mL/kg) than preterm infants without BPD (23.4 mL/kg) and term-born infants (22.6 mL/kg), though there was no trend with disease severity. They also showed higher respiratory rates and lower ratios of time to peak expiratory flow and expiratory time (t(PTEF)/t(E)) than healthy preterm and term controls. These changes were related to disease severity. No differences were found for ventilation inhomogeneity. CONCLUSIONS: Our results suggest that preterm infants with BPD have a high capacity to maintain functional lung volume during natural sleep. The alterations in breathing pattern with disease severity may reflect presence of adaptive mechanisms to cope with the disease process

Monitoring CO2 in shock states

The primary end point when treating acute shock is to restore blood circulation, mainly by reaching macrocirculatory parameters. However, even if global haemodynamic goals can be achieved, microcirculatory perfusion may remain impaired, leading to cellular hypoxia and organ damage. Interestingly, few methods are currently available to measure the adequacy of organ blood flow and tissue oxygenation. The rise in tissue partial pressure of carbon dioxide (CO2) has been observed when tissue perfusion is decreased. In this regard, tissue partial pressure of CO2 has been proposed as an early and reliable marker of tissue hypoxia even if the mechanisms of tissue partial pressure in CO2 rise during hypoperfusion remain unclear. Several technologies allow the estimation of CO2 content from different body sites: vascular, tissular (in hollow organs, mucosal or cutaneous), and airway. These tools remain poorly evaluated, and some are used but are not widely used in clinical practice. The present review clarifies the physiology of increasing tissue CO2 during hypoperfusion and underlines the specificities of the different technologies that allow bedside estimation of tissue CO2 content

Infrastructure and Organization of Adult Intensive Care Units in Resource-Limited Settings

In this chapter, we provide guidance on some basic structural requirements, focusing on organization, staffing, and infrastructure. We suggest a closed-format intensive care unit (ICU) with dedicated physicians and nurses, specifically trained in intensive care medicine whenever feasible. Regarding infrastructural components, a reliable electricity supply is essential, with adequate backup systems. Facilities for oxygen therapy are crucial, and the choice between oxygen concentrators, cylinders, and a centralized system depends on the setting. For use in mechanical ventilators, a centralized piped system is preferred. Facilities for proper hand hygiene are essential. Alcohol-based solutions are preferred, except in the context of Ebola virus disease (chloride-based solutions) and Clostridium difficile infection (soap and water). Availability of disposable gloves is important for self-protection; for invasive procedures masks, caps, sterile gowns, sterile drapes, and sterile gloves are recommended. Caring for patients with highly contagious infectious diseases requires access to personal protective equipment. Basic ICU equipment should include vital signs monitors and mechanical ventilators, which should also deliver noninvasive ventilator modes. We suggest that ICUs providing invasive ventilatory support have the ability to measure end-tidal carbon dioxide and if possible can perform blood gas analysis. We recommend availability of glucometers and capabilities for measuring blood lactate. We suggest implementation of bedside ultrasound as diagnostic tool. Finally, we recommend proper administration of patient data; suggest development of locally applicable bundles, protocols, and checklists for the management of sepsis; and implement systematic collection of quality and performance indicators to guide improvements in ICU performance