- 4k Downloads
The potential for high stretch mechanical ventilation to cause ventilator induced lung injury (VILI) and worsen the severity of ARDS is clear. Protective ventilatory strategies that reduce tidal and minute ventilation improve outcome in children with severely injured lungs. The high levels of PaCO2 arising from restrictive ventilation are well tolerated clinically and have been termed ‘Permissive Hypercapnia’. The benefits of ventilatory strategies incorporating permissive hypercapnia are assumed to be a result of reduced lung stretch. However hypercapnia itself has the potential to exert a multitude of beneficial – and harmful – effects, and should not be thought of as a mere ‘bystander’.
This chapter will focus on ventilator strategies involving permissive hypercapnia in neonates and infants with acute respiratory failure. Using evidence gathered from laboratory studies, we will examine the biological effects of hypercapnia on organ systems and the modulating effects that hypercapnia has on systemic and lung injury models. The evidence that hypercapnia may exert direct effects on the severity of lung injury will be considered. The role of permissive hypercapnia in a variety of clinical settings of relevance to neonatal and paediatric practice will then be discussed. Finally the risks and benefits of permissive hypercapnia will be considered in specific clinical situations.
KeywordsLung Injury Pulmonary Vascular Resistance Hypoplastic Left Heart Syndrome Congenital Diaphragmatic Hernia Ventilator Induce Lung Injury
- Amato MB, Barbas CS, Medeiros DM, Schettino G, Lorenzi Filho G, Kairalla RA et al (1995) Beneficial effects of the “open lung approach” with low distending pressures in acute respiratory distress syndrome. A prospective randomized study on mechanical ventilation. Am J Respir Crit Care Med 152(6 Pt 1):1835–1846PubMedGoogle Scholar
- Keenan RJ, Todd TR, DeMajo W, Slutsky AS (1990) Effects of hypercarbia on arterial and alveolar oxygen tensions in a model of gram-negative pneumonia. J Appl Physiol 68:1820–1825Google Scholar
- Ni Chonghaile M, Higgins BD, Costello J, Laffey JG (2008b) Hypercapnic acidosis attenuates lung injury induced by established bacterial pneumonia. Anesthesiology 109(5):837–848Google Scholar
- Nomura F, Aoki M, Forbess JM, Mayer JE (1994) Effects of hypercarbic acidotic reperfusion on recovery of myocardial function after cardioplegic ischemia in neonatal lambs. Circulation 90:321–327Google Scholar
- Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. The Acute Respiratory Distress Syndrome Network (2000) N Engl J Med 342(18):1301–1308Google Scholar
- von Planta I, Weil MH, von Planta M, Gazmuri RJ, Duggal C (1991) Hypercarbic acidosis reduces cardiac resuscitability. Crit Care Med 19(9):1177–1182Google Scholar