Cardiorespiratory effects of flexible fiberoptic bronchoscopy in critically ill patients.

Abstract

The flexible fiberoptic bronchoscope is used increasingly often as a multipurpose instrument in critical care medicine. In poor risk patients who need continuous mechanical ventilation, rigid open tube bronchoscopy is a problem. With the flexible fiberoptic bronchoscope, however, diagnostic and therapeutic procedures can be carried out without interruption of ongoing mechanical ventilation. This procedure offers the possibility of bronchoscopy with reduced risk in debilitated patients. However, in these critically ill patients, the cardiopulmonary system is functioning at the borderline of its ability. Therefore, even the small changes in ventilation pattern caused by flexible fiberoptic bronchoscopy (FFB) may in some cases cause dangerous cardiopulmonary distress. For example, changes of intrabronchial pressure, tidal volume, PaO2, PaCO2 and cardiac output may be caused by the procedure. Further, it is of great importance to restrict suction through the instrument to short periods to avoid dangerous alterations in the ventilation perfusion relationship. Since serious complications may occur, it is mandatory that the bronchoscopist be aware of the potential pathophysiologic effects of FFB during mechanical ventilation of critically ill patients.

Indications and Efficacy of Fiberoptic Bronchoscopy in the ICU: Have They Changed Since Its Introduction in Clinical Practice?

“…In this series, a drop in SpO 2 >5% was observed in 65% of patients during FOB, with post-FOB SpO 2 values not significantly different from pre-FOB values. In a study by Lindholm et al [40], it was observed that gas exchange abnormalities slowly return to baseline after FOB and that PaO 2 values could decrease by about 40% if suctioning is applied during FOB. Krell [43] described that critically ill patients could experience a PaO 2 drop greater than the average 20 mm Hg observed in healthy subjects, with decreases of 30 to 60 mm Hg during FOB, and that hypoxemia may persist for several hours after the procedure.…”

“…They are often unstable and have failure of one or more organs. This could raise concern for the safety of FOB [4,40]. Bronchoscopy has demonstrated to be a safe procedure with a low rate of complications, even in training programs [41,42].…”

Indications for flexible fiberoptic bronchoscopy and its safety in the very elderly

“…Serious cardiac adverse events, such as atrial and ventricular arrhythmias, myocardial ischemia, angina, and cardiac arrest are uncommon [3,5,30,[34][35][36]. They have been linked to sedation, hypoxemia [37], passage of the bronchoscope through the vocal cords [34], and pre-treatment with lidocaine anaesthetic.…”

Flexible Bronchoscopy Assisted by Noninvasive Positive Pressure Ventilation

“…The flexible bronchoscope occupies 10% to 15% of a normal tracheal lumen 9 ; resulting hypoventilation may prompt a decrease in PaO 2 by 10 to 20 mm Hg. Procedures may also induce or exacerbate bronchospasm, 10 and, in the presence of hypoxemia, increase the risk of respiratory insufficiency or cardiac arrhythmias.…”