Summary: Fiberoptic Bronchoscopy
Fiberoptic bronchoscopy is widely used in pulmonary medicine for diagnostic and treatment goals. During this procedure patients are sedated in order to suppress cough, gag reflex and movements which interferes with the procedure. Maintaining adequate ventilation in such situation is an issue of utmost importance. Nasal oxygen supply suffices for maintaining o₂ saturation over 90% in mildly sedated patients, however when deeper sedation is needed during the procedure, dropping oxygen and rising CO₂ pressure, acidemia and arrhythmia is a frequent problem faced. Different approaches have been introduced for ventilating deeply sedated patients (like apneic oxygenation , spontaneous assisted ventilation ,controlled ventilation, etc.)[1].Among
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Alternative mechanisms of gas transport (Tylor dispersion , pendelluft effect ,cardiogenic mixing) facilitates gas exchange during application of this technique.[3, 4] This technique received most attention lately as a ventilation technique which leaves the field open for intervention tools as well as providing adequate gas exchange without suppressing cardiac output or increasing chance of barotrauma[5]. Complications reported after prolonged HFJV usage include: barotrauma, mucosal trauma or necrosis of trachea due to dry gas exposure, as well as complications related to impaired ventilation such as hypoxia , hypercapnia and airway soiling by debris(3). HFJV can be applied via supraglottic (such as laryngeal mask airway), trans-tracheal or subglottic approaches, each has advantages and disadvantages. The advantage of supraglottic approach is that it provides a tubeless field rather than subglottic approach, however supraglottic approach causes rapid increase in airway pressure compared to subglottic method thus increases the risk of barotrauma , impairs ventilation and consequently results in hypercapnia and blowing debris or secretions into lungs[6-9]. HFJV have been increasingly used in several ways: Via the lateral port of rigid bronchoscope[10-13],trans-tracheally[14]or by moving catheter through bronchoscope [15, 16]and using nasotracheal or orotracheal catheters[17,
Alternative mechanisms of gas transport (Tylor dispersion , pendelluft effect ,cardiogenic mixing) facilitates gas exchange during application of this technique.[3, 4] This technique received most attention lately as a ventilation technique which leaves the field open for intervention tools as well as providing adequate gas exchange without suppressing cardiac output or increasing chance of barotrauma[5]. Complications reported after prolonged HFJV usage include: barotrauma, mucosal trauma or necrosis of trachea due to dry gas exposure, as well as complications related to impaired ventilation such as hypoxia , hypercapnia and airway soiling by debris(3). HFJV can be applied via supraglottic (such as laryngeal mask airway), trans-tracheal or subglottic approaches, each has advantages and disadvantages. The advantage of supraglottic approach is that it provides a tubeless field rather than subglottic approach, however supraglottic approach causes rapid increase in airway pressure compared to subglottic method thus increases the risk of barotrauma , impairs ventilation and consequently results in hypercapnia and blowing debris or secretions into lungs[6-9]. HFJV have been increasingly used in several ways: Via the lateral port of rigid bronchoscope[10-13],trans-tracheally[14]or by moving catheter through bronchoscope [15, 16]and using nasotracheal or orotracheal catheters[17,