Accuracy of pleural puncture sites -: A prospective comparison of clinical examination with ultrasound

Study objective: To assess the value of chest ultrasonography vs; clinical examination for planning of diagnostic pleurocentesis (DPC). Design: Prospective comparative study. Setting: Pulmonary unit of a tertiary teaching hospital. Patients and participants: Sixty-seven consecutive patients referred to 30 physicians of varying degrees of experience for DPC. Interventions: Based on clinical data and examination, physicians determined whether and where a DPC should be performed. Selected puncture sites were evaluated with. ultrasound and considered accurate when greater than or equal to 10 mm fluid perpendicular to the skin were present. Measurements and results: In 172 of 255 cases (67%), a puncture site was proposed. Twenty-five sites (15%) were found to be inaccurate on ultrasound examination, and a different, accurate site was established in 20 of these cases. Physicians were unable to locate a puncture site in 83 cases (33%). Among these, ultrasound demonstrated an accurate site in 45 cases (54%), while a safe tap was truly impossible in 38 cases (46%). Overall, ultrasound prevented possible accidental organ puncture in 10% of all cases and increased the rate of accurate sites by 26%. The sensitivity and specificity for identifying a proper puncture site with clinical examination compared to ultrasound as the "gold standard" were 76.6% and 60.3% (positive and negative predictive values, 85.5% and 45.8%, respectively). Risk factors associated with inaccurate clinical site selection were as follows: small effusion (p < 0.001), evidence of fluid loculation on chest radiography (p = 0.01; relative risk, 7.8; 95% confidence interval, 1.9 to 32.9), and sharp costodiaphragmatic angle on chest radiography (p < 0.001; relative risk, 7.0; 95% confidence interval, 2.3 to 15.2). Experienced physicians did not perform better than physicians in training. Conclusions: Puncture site selection with bedside ultrasonography increases the yield of and potentially reduces complication rate in DPC. Physician experience does not predict the accuracy of selected puncture sites.