RATIONALE: Pleural fluid (PF) pH is highly specific and sensitive for identifying patients at risk of complicated parapneumonic effusion (CPPE). As PF pH and pleural fluid glucose (PFG) are strongly correlated, PFG can act as a surrogate when immediate pH measurement is unfeasible. In an appropriate clinical context, low PFG suggests a higher probability of CPPE, supporting chest drain insertion. To our knowledge, this is the first study to assess PFG measurement accuracy using point-of-care (POC) arterial blood gas analyzer (ABGA) compared to delayed standard laboratory analysis (LAB-PFG). METHODS: We enrolled adult outpatients with pleural effusion undergoing diagnostic thoracentesis at Pisa University Hospital's Pulmonology Unit. Exclusion criteria included inability to obtain informed consent or PF during thoracentesis. Glucose and pH were measured simultaneously using a GEM Premier 5000® ABGA (Werfen). PF samples were then sent to the laboratory for biochemical analysis, cytology, and microbiology. The primary outcome was to compare the accuracy of POC ABGA with standard laboratory methods for measuring PFG. Statistical analysis included Pearson correlation coefficient and Bland-Altman plot. RESULTS: A total of 31 patients were included, with a mean age of 73 ± 15 years. Pleural effusions were classified as follows: 53.6% malignant, 17.9% cardiogenic, 10.7% parapneumonic, 7.1% of other origins, and 10.7% with an indefinite diagnosis. The Pearson correlation coefficient demonstrated a strong correlation between Lab-PFG and ABGA-PFG (r = 0.99, 95% CI 0.97- 0.99; P < 0.001). Mean PFG concentrations were 116.3 ± 30.1 mg/dL in the laboratory, and 111.5 ± 37.7 mg/dL with the ABGA. The Bland-Altman analysis showed a mean bias of 4.58 mg/dL between ABGA-PFG and Lab-PFG (95% LoA: -5.15 to 14.31 mg/dL). CONCLUSIONS: This study is the first to demonstrate a significant correlation between POC ABGA and laboratorybased PFG measurements. The utilization of POC ABGA for PFG assessment offers several advantages. It enables a comprehensive evaluation by simultaneously measuring PFG, pH, and hematocrit, thereby enhancing diagnostic accuracy. The rapid turnaround time, eliminating the need for laboratory sample processing, is crucial in emergencies, for critically ill patients, facilitating timely clinical decision-making. Additionally, PFG measurements are less susceptible to inaccuracies stemming from collection methods or contamination by substances such as air, lidocaine, or heparin compared to conventional pH measurements. Despite limitations, our findings suggest that POC ABGA for PFG evaluation may be both accurate and reliable. Comprehensive multicenter studies utilizing diverse ABGA devices are necessary to validate these findings and assess broader clinical utility.
Real-Time Reliability: Unveiling the Accuracy of Pleural Fluid Glucose Measurement with Point-of-Care Arterial Blood Gas Analyzer Technology
Marchi, G.;Cucchiara, F.;Guglielmi, G.;Pistelli, F.;Carrozzi, L.
2025-01-01
Abstract
RATIONALE: Pleural fluid (PF) pH is highly specific and sensitive for identifying patients at risk of complicated parapneumonic effusion (CPPE). As PF pH and pleural fluid glucose (PFG) are strongly correlated, PFG can act as a surrogate when immediate pH measurement is unfeasible. In an appropriate clinical context, low PFG suggests a higher probability of CPPE, supporting chest drain insertion. To our knowledge, this is the first study to assess PFG measurement accuracy using point-of-care (POC) arterial blood gas analyzer (ABGA) compared to delayed standard laboratory analysis (LAB-PFG). METHODS: We enrolled adult outpatients with pleural effusion undergoing diagnostic thoracentesis at Pisa University Hospital's Pulmonology Unit. Exclusion criteria included inability to obtain informed consent or PF during thoracentesis. Glucose and pH were measured simultaneously using a GEM Premier 5000® ABGA (Werfen). PF samples were then sent to the laboratory for biochemical analysis, cytology, and microbiology. The primary outcome was to compare the accuracy of POC ABGA with standard laboratory methods for measuring PFG. Statistical analysis included Pearson correlation coefficient and Bland-Altman plot. RESULTS: A total of 31 patients were included, with a mean age of 73 ± 15 years. Pleural effusions were classified as follows: 53.6% malignant, 17.9% cardiogenic, 10.7% parapneumonic, 7.1% of other origins, and 10.7% with an indefinite diagnosis. The Pearson correlation coefficient demonstrated a strong correlation between Lab-PFG and ABGA-PFG (r = 0.99, 95% CI 0.97- 0.99; P < 0.001). Mean PFG concentrations were 116.3 ± 30.1 mg/dL in the laboratory, and 111.5 ± 37.7 mg/dL with the ABGA. The Bland-Altman analysis showed a mean bias of 4.58 mg/dL between ABGA-PFG and Lab-PFG (95% LoA: -5.15 to 14.31 mg/dL). CONCLUSIONS: This study is the first to demonstrate a significant correlation between POC ABGA and laboratorybased PFG measurements. The utilization of POC ABGA for PFG assessment offers several advantages. It enables a comprehensive evaluation by simultaneously measuring PFG, pH, and hematocrit, thereby enhancing diagnostic accuracy. The rapid turnaround time, eliminating the need for laboratory sample processing, is crucial in emergencies, for critically ill patients, facilitating timely clinical decision-making. Additionally, PFG measurements are less susceptible to inaccuracies stemming from collection methods or contamination by substances such as air, lidocaine, or heparin compared to conventional pH measurements. Despite limitations, our findings suggest that POC ABGA for PFG evaluation may be both accurate and reliable. Comprehensive multicenter studies utilizing diverse ABGA devices are necessary to validate these findings and assess broader clinical utility.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
