RIGHT-VENTRICULAR FUNCTION AND PLASMA ATRIAL-NATRIURETIC-PEPTIDE LEVELS DURING FIBERBRONCHOSCOPIC ALVEOLAR-LAVAGE IN CRITICALLY ILL, MECHANICALLY VENTILATED PATIENTS

Study objective: To assess the influence of fiberbronchoscopic alveola r lavage on hemodynamics, right ventricular function, and plasma atria l natriuretic peptide (ANP) concentrations in critically ill, mechanic ally ventilated patients. Design: Prospective investigation. Setting: Eight-bed ICU of a university hospital. Patients: Fourteen patients wi th cardiovascular instability due to a systemic inflammatory response syndrome who were mechanically ventilated. Interventions: Fiberbroncho scopic alveolar lavage after fluid replacement, deep sedation, and par alyzation. Intervention time: 10 min. After inspection of the endobron chial system, one lavage of 40 mt sterile saline solution was instille d in each lung and recovered. Measurements and results: The fiberbronc hoscopic procedure induced a prompt increase in mean pulmonary arteria l pressure after 3 min (median [range]: 25 [13 to 39] to 30 [19 to 45] mn Hg, p<0.05), which increased further after 6 min (34 [17 to 46] mm Hg, p<0.01). Cardiac index increased simultaneously (4.25 [3.1 to 5.7 ] to 4.85 [4.3 to 6.9] L/min . m(2) after 6 min, p<0.01), whereas mean arterial pressure and heart rate remained unchanged Central venous pr essure rose from 12 (3 to 18) mm Hg before procedure to 14 (4 to 20) m m Hg after 6 min (p<0.01). The right ventricular function was measured using a ''fast response'' ejection fraction thermodilution catheter: end-diastolic volume increased (238 [137 to 358] to 280 [150 to 4II] m L after 9 min, p<0.05), as well as stroke volume (88 [54 to 113] to 10 3 [67 to 153] mL after 9 min, p<0.01). Right ventricular ejection frac tion (37 [25 to 50] %) did not change significantly during the procedu re, but the stroke work index was reinforced (8.2[4.7 to 15.7] to 13.3 [2.4 to 41.3] gm . M/M(2) after 6 min, p<0.01). Plasma c-ANP concentr ation rose from 135 (24 to 350) to 196.5 (44 to 830) pg/mL, after 20 m in (p<0.05). Systemic vascular resistance decreased from 538 (390 to 1 ,042) to 429 (281 to 684) dynes . s/cm(5) after removal of the broncho scope (p<0.01). Conclusions: Although acute pulmonary hypertension was observed during the fiberbronchoscopic procedure, the right ventricul ar performance did not deteriorate in hemodynamically unstable patient s. To maintain a ''hyperdynamic cardiovascular state,'' the right vent ricular stroke work was reinforced, presumably by the ''Frank-Starling mechanism.'' We assume that the acute distention of the right side of the heart resulted in elevated ANP concentrations. The marked decreas e in systemic vascular resistance might be due to high AMP levels.