Handheld “jet” ventilation, using high pressure to move air through small catheters, was conceived in the 1960s in an attempt to develop a device that would both maintain adequate ventilation/oxygenation and allow surgical access to the airway during endotracheal and laryngeal procedures.¹,² Recently, this type of jet ventilation, applied via a needle placed through the cricothyroid membrane (transtracheal jet ventilation, or TTJV), is one option to restore oxygenation in the setting of an emergent difficult airway, in which neither intubation nor ventilation is possible, as recommended in the American Society of Anesthesiologists Difficult Airway Algorithm.³ Understanding this device and its application can be life saving.

The oxygen jet stream for TTJV requires a highpressure device. This pressure can be delivered through a supplementary pipeline, an oxygen tank with a step-down regulator, or an anesthesia machine. The working pressure that is necessary to achieve flow through a 14G catheter should be 15 psi (103 pka) at a minimum. The pipeline oxygen delivered pressure from the wall in a hospital is 55 psi. Modern anesthesia machines provide a specific connection for a handheld TTJV device, which provides adequate pressure for this device to function properly (Fig. 29-1).⁴

Manufactured TTJV devices incorporate a pressure regulator, which allows a variable pressure to be applied, and oxygen delivery is controlled with a handheld on/off valve (Fig. 29-2). Several other self-assembled devices have been adapted to connect to the handheld jet ventilator, though these are less reliable in delivery of adequate ventilation than devices designed specifically for this purpose.

The delivery of this type of jet ventilation may be performed in two ways: high frequency and low frequency. The former is typically used in intensive care units to provide very small tidal volumes for patients with poor lung compliance (see Chapter 48). Low-frequency jet ventilation through a transtracheal catheter is used in the setting of difficult airway management, when in the “emergent pathway” of the difficult airway algorithm, necessitating immediate ventilation. The handheld jet device can also be used for oxygenation during a bronchoscopy or a rigid laryngoscopy procedure (see Chapter 43). The typical frequency of ventilation in such settings is 8 to 10 breaths per minute, allowing enough time for exhalation, and decreasing the risk of air-trapping and barotrauma. Exhalation should be confirmed by observing chest motion before a subsequent tidal volume is delivered.

With TTJV, the FiO₂ delivered is lower than 100%, because ambient air is entrained with each pulse of highpressure gas. Alveolar ventilation is dependent on the ventilatory rate and the effective tidal volume. Delivered gas flow during ventilation is typically in the range of 0.5 to 1 L per second, depending upon catheter size. Because there is a risk of increased intrathoracic pressure with every inhalation, the inspiratory time should be limited to 0.5 or 1 second. A pause between insufflations is performed, allowing passive exit of the air secondary to the recoil of the chest wall (an inspiratory to expiratory ratio of 1:3 or 1:4 is appropriate). This methodology assumes a normal lung compliance (50 mL/cm H₂0), with a pressure delivery system not higher than 50 psi. However, in a lung with reduced compliance, more careful delivery of the insufflations should be performed, with an eye toward avoiding dangerously high inspiratory pressures.

There are several types of catheters available to perform needle cricothyroidotomy for TTJV. Fourteen-gauge or sixteen-gauge intravenous-type catheters are commonly used, and commercial devices are available as well, some with reinforcement to prevent kinking (Fig. 29-3). The VBM Manujet III (VBM medical, Noblesville, IN, USA) package includes the handheld jet ventilation device, a jet injector and teflon catheters, in sizes 13G, 14G, and 16G, for infants and adults. These catheters have a Luer lock to facilitate connection to the handheld jet ventilator. In addition, the distal parts of these catheters have lateral holes to decrease the venturi effect and to maintain the catheters far from the tracheal wall.⁵

TTJV was demonstrated to provide adequate ventilation in cardiac arrest patients as early as 1972, when Jacobs described its use in 40 cases.⁶ While using a high-pressure oxygen source, the author was able to maintain an average PaO₂ of 300 mm Hg, and a PaCO₂ of 22 mm Hg with peak airway pressures of 15 to 25 cm H₂O. In 1975, Smith⁷ described the use of TTJV in 80 patients who underwent airway surgery under general anesthesia. Fifty-two of these cases involved elective use of the technique, whereas 28 of the patients were managed while in respiratory distress. Several case series have shown the benefit of this technique in patients with significant airway disease and severe glottic narrowing, in whom tracheostomy would be difficult.⁸ Provided that adequate pressures are used to provide necessary flow rates, several investigators have demonstrated that normocarbia can be maintained while ventilating patients with TTJV.⁹,¹⁰ Many of the patients described in these investigations were under general anesthesia, in contrast to patients in acute respiratory failure who are frequently encountered in the hospital wards, intensive care units, or emergency department. TTJV also has been useful in high-grade upper airway obstruction, as in the case of a patient with a large carcinoma at the base of the tongue who sustained a respiratory arrest.¹¹