Metabolic acid-base adaptation triggered by acute persistent hypercapnia in mechanically ventilated patients with acute respiratory distress syndrome
Open Access
- 1 January 2016
- journal article
- Published by GN1 Sistemas e Publicacoes Ltd. in Revista Brasileira de Terapia Intensiva
- Vol. 28 (1), 19-26
- https://doi.org/10.5935/0103-507x.20160009
Abstract
Hypercapnia resulting from protective ventilation in acute respiratory distress syndrome triggers metabolic pH compensation, which is not entirely characterized. We aimed to describe this metabolic compensation. The data were retrieved from a prospective collected database. Variables from patients' admission and from hypercapnia installation until the third day after installation were gathered. Forty-one patients with acute respiratory distress syndrome were analyzed, including twenty-six with persistent hypercapnia (PaCO2 > 50mmHg > 24 hours) and 15 non-hypercapnic (control group). An acid-base quantitative physicochemical approach was used for the analysis. The mean ages in the hypercapnic and control groups were 48 ± 18 years and 44 ± 14 years, respectively. After the induction of hypercapnia, pH markedly decreased and gradually improved in the ensuing 72 hours, consistent with increases in the standard base excess. The metabolic acid-base adaptation occurred because of decreases in the serum lactate and strong ion gap and increases in the inorganic apparent strong ion difference. Furthermore, the elevation in the inorganic apparent strong ion difference occurred due to slight increases in serum sodium, magnesium, potassium and calcium. Serum chloride did not decrease for up to 72 hours after the initiation of hypercapnia. In this explanatory study, the results indicate that metabolic acid-base adaptation, which is triggered by acute persistent hypercapnia in patients with acute respiratory distress syndrome, is complex. Furthermore, further rapid increases in the standard base excess of hypercapnic patients involve decreases in serum lactate and unmeasured anions and increases in the inorganic apparent strong ion difference by means of slight increases in serum sodium, magnesium, calcium, and potassium. Serum chloride is not reduced.Keywords
This publication has 34 references indexed in Scilit:
- Clinical outcomes of patients requiring ventilatory support in Brazilian intensive care units: a multicenter, prospective, cohort studyCritical Care, 2013
- Urinary electrolyte monitoring in critically ill patients: a preliminary observational study.2012
- Acute renal response to rapid onset respiratory acidosisCanadian Journal of Physiology and Pharmacology, 2011
- Hypercapnic acidosis and mortality in acute lung injury*Critical Care Medicine, 2006
- Incidence and Outcomes of Acute Lung InjuryThe New England Journal of Medicine, 2005
- Ventilation with Lower Tidal Volumes as Compared with Traditional Tidal Volumes for Acute Lung Injury and the Acute Respiratory Distress SyndromeThe New England Journal of Medicine, 2000
- Temporal Hemodynamic Effects of Permissive Hypercapnia Associated with Ideal PEEP in ARDSAmerican Journal of Respiratory and Critical Care Medicine, 1997
- A physical-chemical analysis of the acid-base response to chronic obstructive pulmonary disease.1996
- Relationships Between Lung Computed Tomographic Density, Gas Exchange, and PEEP in Acute Respiratory FailureAnesthesiology, 1988
- Experimental pulmonary edema due to intermittent positive pressure ventilation with high inflation pressures. Protection by positive end-expiratory pressure.Published by Elsevier BV ,1974