Abstract
BackgroundHypercapnic Chronic Obstructive Pulmonary Disease (COPD) exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV) when treating hypercapnic respiratory failure.MethodsSixty-seven consecutive patients who were hospitalized for hypercapnic COPD exacerbation had their clinical condition, respiratory function, blood chemistry, arterial blood gases, blood lactate and volemic state assessed. Heart and respiratory rates, pH, PaO2 and PaCO2 and blood lactate were checked at the 1st, 2nd, 6th and 24th hours after starting NIV.ResultsNine patients were transferred to the intensive care unit. NIV was performed in 11/17 (64.7%) mixed respiratory acidosis–metabolic alkalosis, 10/36 (27.8%) respiratory acidosis and 3/5 (60%) mixed respiratory-metabolic acidosis patients (p = 0.026), with durations of 45.1±9.8, 36.2±8.9 and 53.3±4.1 hours, respectively (p = 0.016). The duration of ventilation was associated with higher blood lactate (p<0.001), lower pH (p = 0.016), lower serum sodium (p = 0.014) and lower chloride (p = 0.038). Hyponatremia without hypervolemic hypochloremia occurred in 11 respiratory acidosis patients. Hypovolemic hyponatremia with hypochloremia and hypokalemia occurred in 10 mixed respiratory acidosis–metabolic alkalosis patients, and euvolemic hypochloremia occurred in the other 7 patients with this mixed acid-base disorder.ConclusionsMixed acid-base and lactate disorders during hypercapnic COPD exacerbations predict the need for and longer duration of NIV. The combination of mixed acid-base disorders and hydro-electrolyte disturbances should be further investigated.
Highlights
Hypercapnic respiratory failure is a complex condition associated with the malfunction of various organs and systems crucial for many physiological processes, leading to an acid-base imbalance.Carbon dioxide (CO2) is not the only independent variable that may cause alterations in acid-base status
Between January and April 2010, 75 patients were consecutively hospitalized for Chronic Obstructive Pulmonary Disease (COPD) exacerbation and hypercapnic respiratory failure, but 67 were enrolled in the study population (5 patients were excluded for being on chronic noninvasive ventilation (NIV) treatment at home and the other 3 for the presence of concomitant pneumonia)
We considered 58 of the 67 patients initially enrolled, as 9 were excluded because they were transferred to the intensive care unit for pH,7.1, hypercapnic coma or hemodynamic instability (Figure 1)
Summary
Hypercapnic respiratory failure is a complex condition associated with the malfunction of various organs and systems crucial for many physiological processes, leading to an acid-base imbalance. Carbon dioxide (CO2) is not the only independent variable that may cause alterations in acid-base status. Altering SID means altering the water dissociation equilibrium. This provides more/less H+ for electroneutrality, with a change in [H+], and so a change in pH. Hypercapnic Chronic Obstructive Pulmonary Disease (COPD) exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV) when treating hypercapnic respiratory failure
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