High frequency jet ventilation

A case is described where high frequency jet ventilation was used to avoid the cardiovascular depressant effects associated with conventional ventilation. Early weaning from inotropic and ventilatory support proved possible.     

High frequency jet ventilation

High frequency jet ventilation for thoracic surgery offers some practical advantages over intermittent pressure ventilation using bronchial tubes. Satisfactory blood gases were obtained in 50 patients and good operating conditions were provided.     

High frequency jet ventilation in intensive care—a review of 63 patients

High frequency jet ventilation has been used clinically in this unit for over 2 years. During this time we have treated 63 intensive care patients for whom the mean duration of ventilatory support was 3.4 days, which represents more than 5000 patient hours in total, with the Penlon Bromsgrove humidified jet ventilator. The series comprises a wide variety of general intensive care patients; a review of these cases is presented.     

High frequency jet ventilation for bilateral bullectomy

This case report describes the use of high frequency jet ventilation for resection of bilateral lung bullae. Low airway pressures reduced the risk of pulmonary barotrauma. A continuous infusion of ketamine provided acceptable anaesthesia.     

Combined unilateral high frequency jet ventilation and contralateral intermittent positive pressure ventilation

The anaesthetic management of a patient who required right lower lobectomy for bronchial carcinoma associated with emphysema, pneumoconiosis and a previous thoracoplasty for pulmonary tuberculosis, is described. A technique of unilateral high frequency jet ventilation plus conventional intermittent positive pressure ventilation to the contralateral lung was used.     

Comparison of conventional intermittent positive pressure ventilation with high frequency jet ventilation

This study was designed to compare the cardiorespiratory effects of high frequency jet ventilation at 150 breaths/minute with and without added positive and expiratory pressure, with conventional intermittent positive pressure ventilation in 20 patients following aortocoronary bypass graft surgery. On comparison with intermittent positive pressure ventilation, there was a decrease in peak airway pressure during high frequency jet ventilation when positive and expiratory pressure of 0 or 0.5 kPa was applied, but not with 1 kPa, and an increase in mean airway pressure with positive end expiratory pressures of 0.5 and 1 kPa. On changing from intermittent positive pressure to high frequency jet ventilation with no added end expiratory pressure, there was an acute decrease in arterial oxygen tension and increases in cardiac output and total tissue oxygen delivery. On changing from intermittent positive pressure ventilation to high frequency jet ventilation with 1 kPa of positive end expiratory pressure, there was an acute decrease in arterial oxygen tension, cardiac output and oxygen delivery, and increases in pulmonary arterial, right atrial and pulmonary capillary wedge pressures. The addition of positive end expiratory pressure did not prevent the acute decrease in arterial oxygen tension which occurred on transfer to high frequency jet ventilation.     

Double frequency jet ventilation for endolaryngeal laser surgery

There are a large number of ventilation methods for endolaryngeal laser microsurgery but unfortunately all have their drawbacks. From December 1990 to August 1992 the authors performed 57 operations using intratracheal (infraglottic) jet ventilation with specially designed equipment. The patients' tracheae were translaryngeally intubated with small bore double-lumen copper pipes and ventilation of the lungs commonly performed either with manually controlled oxygen jets or our variant of high frequency jet ventilation (HFJV), the so-called double frequency jet ventilation (DFJV). In this ventilation mode we added the conventional inflation of the lungs to basic HFJV (most often 3 Hz). This was achieved by creating the auto-PEEP, with cyclic variation of I:E ratio from 1:9 to 9:1. Surgical conditions in all cases were rated good. There were no serious complications. Important points for the avoidance of barotrauma, the most dangerous complication in these ventilation methods, are discussed extensively below.     

Transtracheal high frequency jet ventilation for endoscopic airway surgery: a multicentre study

Serious complications during high frequency jet ventilation(HFJV) are rare and have been documented in animals and in casereports or short series of patients with a difficult airway.We report complications of transtracheal HFFJV in a prospectivemulticentre study of 643 patients having laryngoscopy or laryngeallaser surgery. A transtracheal catheter could not be insertedin two patients (0.3%). Subcutaneous emphysema (8.4%) was morefrequent after multiple tracheal punctures. There were sevenpneumothoraces (1%), two after laser damage to the injector,one after difficult laryngoscopy, four with no clear cause.Arterial desaturation of oxygen was more frequent during lasersurgery and in overweight patients. Transtracheal ventilationfrom a ventilator with an automatic cut-off device is a reliablemethod for experienced users. Control of airway pressure doesnot prevent a low frequency of pneumothorax. Br J Anaesth 2001; 87: 870–5     

Intravenous infusion of propofol for induction and maintenance of anaesthesia during endoscopic carbon dioxide laser ENT procedures with high frequency jet ventilation

Fourteen patients of ASA grades 1 3 were anaesthetised with continuous infusions of propofol and alfentanil for endoscopic carbon dioxide laser ENT microsurgery. Their lungs were ventilated with an oxygen-air mixture using a high frequency jet ventilator. Propofol was given at an initial rate of 120 μg/kg/minute for 10 minutes after a bolus dose of 2.6 mg/kg, and then at 80 fig μg/kg/minute. Alfentanil was given at a rate of 0.5 μg/kg/minute. Arterial pressure decreased significantly after the bolus dose. It increased significantly for a few minutes after laryngoscopy and returned to baseline values during maintenance of anaesthesia. Heart rate increased significantly during induction and until laryngoscopy was performed but it decreased below its initial value after 5 minutes of maintenance. Platelet count and the degree of aggregation did not change during infusion of propofol.     

High frequency jet ventilation in fat embolism syndrome

The use of high frequency jet ventilation in the management of a patient with fat embolism syndrome is described. Its principal advantage over conventional intermittent positive pressure ventilation is a reduction in the amount of sedation necessary.     

High frequency jet ventilation via a tracheoscope for endobronchial laser surgery

Palliative surgery of malignant endobronchial tumours is associated with various anaesthetic risks. A technique is described using a neodymium:yttrium-aluminium-garnet (Nd:YAG) laser in combination with a special tracheoscope and high frequency jet ventilation (HFJV). The purpose of this technique is to provide separation of anaesthetic and surgical manipulations, good conditions of ventilation and easy access to the lungs for the surgeon. We present our experience with 14 adult patients in whom large endobronchial neoplasms were resected using this technique under intravenous anaesthesia and muscle relaxation. Careful perioperative monitoring and a good outcome allowed us to conclude that this set-up may contribute to improving efficiency and safety of endoscopic resections of endobronchial and/or endotracheal tumours.     

Tubeless combined high-frequency jet ventilation for laryngotracheal laser surgery in paediatric anaesthesia

BACKGROUND: High-frequency jet ventilation (HFJV) is an alternative ventilatory approach in airway surgery and for facilitating gas exchange in patients with pulmonary insufficiency. We have developed a new technique of combined HFJV utilising two superimposed jet streams. In this study we describe the application of tubeless supralaryngeal HFJV during laryngotracheal laser surgery in infants and children. METHODS: Tubeless combined HFJV characterised by the simultaneous supralaryngeal application of a low-frequency (LF) and a high-frequency (HF) jet stream was evaluated in a clinical study in 10 children undergoing elective laryngotracheal CO2 laser surgery. Additionally, pressure and flow characteristics were determined with the use of a paediatric test lung. HFJV was applied by means of a modified Kleinsasser laryngoscope with integrated metal injectors. In addition to pulse oximetry, monitoring of ECG, heart rate and blood pressure, supraglottic airway pressure was measured and arterial blood gases were analysed. RESULTS: Tubeless combined HFJV was used in 10 infants and children (mean age 4.6 yr, range 2 months-10 years) undergoing 17 consecutive endoscopic procedures with CO2 laser microsurgery of the larynx or the trachea under general anaesthesia.The mean duration of supralaryngeal HFJV was 46 min (range 15-75 min). Mean driving pressures of the HF and the LF jet streams were 0.75 bar and 0.95 bar, respectively. Inspiratory oxygen ratios were in the range 0.4-1.0. HFJV resulted in mean PaO2 and PaCO2 values of 19.7 kPa and 6.1 kPa, respectively. No complications during HFJV were observed. In the test lung, combined HFJV applied with driving pressures of 0.7-1.0 bar and 0.9-1.2 bar for HF and LF jet ventilation, respectively, resulted in maximum peak and baseline distal airway pressures of 17.6 cm H2O and 5.4 cm H2O, respectively. CONCLUSION: The application of the combined double frequency HFJV was effective in maintaining gas exchange in the presence of laryngeal or tracheal stenoses. It provided good visibility of anatomical structures and offered space for surgical manipulation, avoiding the use of combustible material inside the larynx or trachea.