Percutaneous transtracheal jet ventilation (PTTJV) provides emergency ventilatory support in patients who cannot be adequately ventilated with a bag-valve-mask device (with oral or nasal airways), a laryngeal mask airway (LMA), or endotracheally intubated.1,2,10 This includes patients with upper airway foreign bodies or neoplasms, maxillofacial trauma, laryngeal edema, or infection.2,3 It is also used electively with general anesthesia for surgery involving the larynx and subglottic areas.4 PTTJV involves placement of a percutaneous catheter into the trachea and ventilation via a cyclic delivery of tidal volume to the lungs.5
Early studies of transtracheal ventilation used transtracheal catheters connected to 4 to 5 L/min of oxygen.6 Oxygenation with this apparatus was adequate, but patients quickly developed hypercarbia due to lack of ventilation.5 This “apneic oxygenation” also occurs in ventilation through a catheter attached to a bag-valve device.7 The low pressure and flow of oxygen generated by the bag-valve device result in increases in PaCO2 of 4 mmHg/min and the rapid development of respiratory acidosis.1,8 Numerous studies have since demonstrated that intermittent jets of pressurized 100% oxygen at 50 pounds per square inch (psi) allows for both oxygenation and adequate ventilation.8,9
The anterior neck provides direct access to the airway via the trachea as it extends from the larynx into the lungs (Figure 24-1). At the top of the laryngeal skeleton is the thyroid cartilage, which lies at the level of the fourth and fifth cervical vertebrae. The laryngeal prominence of the thyroid cartilage (more prominent in men) is easily palpated with the thumb and index finger. The cricoid cartilage lies just inferior to the thyroid cartilage at the level of the sixth cervical vertebra. It serves as the junction of the larynx and trachea. Multiple cartilaginous rings support the trachea. Between the cricoid and thyroid cartilages lies the cricothyroid membrane. The cricothyroid membrane is a palpable membranous depression just inferior to the laryngeal prominence and is the access site for PTTJV.11 The cricothyroid artery is a branch of the superior thyroid artery. It travels transversely across the cricothyroid membrane just below the thyroid cartilage. Placement of the catheter through the lower half of the cricothyroid membrane will prevent injury to this small artery.22
Airway structures of the neck.
Once the catheter is placed and appropriately connected to an oxygen source, oxygen is delivered via bulk flow through the cannula into the trachea and lungs. Entrainment of room air translaryngeally via the Venturi principle is negligible, even with minimal upper airway obstruction.1 Therefore, near 100% O2 is delivered with each insufflation.
Inhalation occurs through the catheter via a pressurized flow of oxygen. Exhalation occurs passively through the elastic recoil of the lungs and chest wall.10...