Performing repeated noninvasive bedside measures of volume response to intravenous furosemide in acute pulmonary edema: a feasibility assessment.

Optimizing responses to intravenous furosemide (ivF) in acute pulmonary edema is limited by current insensitive noninvasive means of volume assessment. We conducted a pilot study to assess the feasibility of performing repeated measures of echocardiographic and bioimpedance analysis (BIA) parameters and test their response as noninvasive markers of volume response to ivF. We also aimed to identify the most potentially sensitive markers of this response. Patients receiving ivF for a clinical diagnosis of acute cardiogenic pulmonary edema were studied. Echocardiographic and BIA parameters were measured at 0, 0.5, 1, 2, and 3 h after ivF. Intraobserver variability for each parameter was determined. Thirty-one patients were enrolled who were receiving 40-100 mg of ivF. Transmitral (MV) early peak velocity following Valsalva maneuver and transtricuspid (TV) early peak velocity reduced significantly (P= 0.012 and 0.010, respectively), whereas MV deceleration time increased significantly (P= 0.006) in response to ivF. Short-axis inferior vena cava diameter (SIVC) in expiration and inspiration and SIVC corrected for body surface area in expiration and inspiration reduced significantly following ivF (P= 0.039, 0.020, 0.032, and 0.016, respectively). BIA estimates of extracellular water decreased significantly (P= 0.001), whereas impedance (Z) at currents of 5, 50, 100, and 200 kHz increased following ivF; the changes were significant with all but the last parameter (P < 0.0001, 0.006, 0.010, and 0.051, respectively). Maximal change from baseline for each parameter was greater than its respective intraobserver variability. Performing repeated measures of echocardiographic and BIA parameters is feasible in this unstable group of patients. The above panel of parameters could potentially be used to track volume response to ivF and, thus, to optimize treatment in acute pulmonary edema.