Hypophosphatemia as a prognostic value in acute exacerbation of COPD

Abstract

Background: Phosphorus (P) is an essential element in all living cells, it is extremely important in the process of production of adenosine triphosphate, main element in the structure of nucleic acids. Low levels of phosphorus in blood is very rare, however, it may be caused by unbalance between components participating in phosphorus cycle and affect performances of several systems. A low level of phosphorus in the blood increases the exacerbation and the severity of chronic obstructive pulmonary disease (COPD) and requires prolonged ventilation process.

Aim: This study aims to examine the prognostic effects of hypophosphatemia in COPD patients and evaluate the correlation between phosphorus levels and severity, recurrences of attacks, ventilation duration and successful of weaning process.

Methods: Two hundred and fifty-five patients who were admitted because of worsening in COPD, from October 2010-April 2011, were examined. A comparison was made between the group with normal blood phosphorus (2.5-4.5 mg%), group of patients with low phosphorus (2-2.5 mg%) and group with very low phosphorous values (<2.0 mg%).

Results: Ninety-five per cent of all admissions had normal blood phosphorus levels, 3.3% had low phosphorus levels, and only 1.7% of all admissions had very low phosphorus levels. 2.4% of patients had both low levels of phosphorus and potassium. All patients (100%) with very low phosphorus needed mechanical ventilation, compared to 62.5% of patients with low phosphorus and 16.9% of patients with normal phosphorus levels. In addition, 16 ventilated patients (33% of all ventilated patients) had low potassium values.

Summary: Low blood phosphorus levels contribute to an increase in: COPD flare-up, need for ventilation, duration of hospitalisation, days in intensive care units and finally increased rate of mortality. Accordingly, close monitoring and careful adjustment of disorders correlated to electrolyte such as phosphorus, are crucial and may improve prognosis and also increase the survival rate of patients with COPD.

Keywords: Apache score; COPD; exacerbation; mechanical ventilation; phosphorus levels; prognosis.