Supraglottic jet oxygenation and ventilation for obese patients under intravenous anesthesia during hysteroscopy: a randomized controlled clinical trial.

BACKGROUND: Supraglottic jet oxygenation and ventilation (SJOV) can effectively maintain adequate oxygenation in patients with respiratory depression, even in apnea patients. However, there have been no randomized controlled clinical trials of SJOV in obese patients. This study investigated the efficacy and safety of SJOV using WEI Nasal Jet tube (WNJ) for obese patients who underwent hysteroscopy under intravenous anesthesia without endotracheal intubation. METHODS: A single-center, prospective, randomized controlled study was conducted. The obese patients receiving hysteroscopy under intravenous anesthesia were randomly divided into three groups: Control group maintaining oxygen supply via face masks (100% oxygen, flow at 6 L/min), the WNJ Oxygen Group with WNJ (100% oxygen, flow: 6 L/min) and the WNJ SJOV Group with SJOV via WNJ [Jet ventilator working parameters:100% oxygen supply, driving pressure (DP) 0.1 MPa, respiratory rate; (RR): 15 bpm, I/E; ratio 1:1.5]. SpO2, PETCO2, BP, HR, ECG and BIS were continuously monitored during anesthesia. Two-Diameter Method was deployed to measure cross sectional area of the gastric antrum (CSA-GA) by ultrasound before and after SJOV in the WNJ SJOV Group. Episodes of SpO2 less than 95%, PETCO2 less than 10 mmHg, depth of WNJ placement and measured CSA-GA before and after jet ventilation in the WNJ SJOV Group during the operation were recorded. The other adverse events were collected as well. RESULTS: A total of 102 patients were enrolled, with two patients excluded. Demographic characteristics were similar among the three groups. Compared with the Control Group, the incidence of PETCO2 < 10 mmHg, SpO2 < 95% in the WNJ SJOV group dropped from 36 to 9% (P = 0.009),from 33 to 6% (P = 0.006) respectively,and the application rate of jaw-lift decreased from 33 to 3% (P = 0.001), and the total percentage of adverse events decreased from 36 to 12% (P = 0.004). Compared with the WNJ Oxygen Group, the use of SJOV via WNJ significantly decreased episodes of SpO2 < 95% from 27 to 6% (P = 0.023), PETCO2 < 10 mmHg from 33 to 9% (P = 0.017), respectively. Depth of WNJ placement was about 12.34 cm in WNJ SJOV Group. There was no significantly difference of CSA-GA before and after SJOV in the WNJ SJOV Group (P = 0.234). There were no obvious cases of nasal bleeding in all the three groups. CONCLUSIONS: SJOV can effectively and safely maintain adequate oxygenation in obese patients under intravenous anesthesia without intubation during hysteroscopy. This efficient oxygenation may be mainly attributed to supplies of high concentration oxygenation to the supraglottic area, and the high pressure jet pulse providing effective ventilation. Although the nasal airway tube supporting collapsed airway by WNJ also plays a role. SJOV doesn't seem to increase gastric distension and the risk of aspiration. SJOV can improve the safety of surgery by reducing the incidence of the intraoperative involuntary limbs swing, hip twist and cough. TRIAL REGISTRATION: Chinese Clinical Trial Registry. Registration number, ChiCTR1800017028, registered on July 9, 2018.

Transtracheal jet ventilation in the 'can't intubate can't oxygenate' emergency: a systematic review.

BACKGROUND: Transtracheal jet ventilation (TTJV) is recommended in several airway guidelines as a potentially life-saving procedure during the 'Can't Intubate Can't Oxygenate' (CICO) emergency. Some studies have questioned its effectiveness. METHODS: Our goal was to determine the complication rates of TTJV in the CICO emergency compared with the emergency setting where CICO is not described (non-CICO emergency) or elective surgical setting. Several databases of published and unpublished literature were searched systematically for studies describing TTJV in human subjects. Complications were categorized as device failure, barotrauma (including subcutaneous emphysema), and miscellaneous. Device failure was defined by the inability to place and/or use the TTJV device, not patient survival. RESULTS: Forty-four studies (428 procedures) met the inclusion criteria. Four studies included both emergency and elective procedures. Thirty studies described 132 emergency TTJV procedures; 90 were CICO emergencies. Eighteen studies described 296 elective TTJV procedures. Device failure occurred in 42% of CICO emergency vs 0% of non-CICO emergency (P<0.001) and 0.3% of elective procedures (P<0.001). Barotrauma occurred in 32% of CICO emergency vs 7% of non-CICO emergency (P<0.001) and 8% of elective procedures (P<0.001). The total number of procedures with any complication was 51% of CICO emergency vs 7% of non-CICO emergency (P<0.001) and 8% of elective procedures (P<0.001). Several reports described TTJV-related subcutaneous emphysema hampering subsequent attempts at surgical airway or tracheal intubation. CONCLUSIONS: TTJV is associated with a high risk of device failure and barotrauma in the CICO emergency. Guidelines and recommendations supporting the use of TTJV in CICO should be reconsidered.

[Anesthesia in interventional pulmonology -- bronchoscopy and jet ventilation]. / Anästhesie in der interventionellen Pneumologie--Bronchoskopie und Jet-Ventilation.

Today interventional procedures are frequently used for diagnosis and treatment in patients with various pulmonary diseases. Besides bronchoscopy in local- or general anesthesia jet-ventilation is commonly applied via catheter or rigid bronchoscope. Anesthesiologists should have profound knowledge of high-frequency ventilation and possible complications when assisting during interventional procedures.

High-frequency jet ventilation under general anesthesia facilitates CT-guided lung tumor thermal ablation compared with normal respiration under conscious analgesic sedation.

PURPOSE: To determine whether technical difficulty of computed tomography (CT)-guided percutaneous lung tumor thermal ablations is altered with the use of high-frequency jet ventilation (HFJV) under general anesthesia (GA) compared with procedures performed with normal respiration (NR) under conscious sedation (CS). MATERIALS AND METHODS: Thermal ablation treatment sessions performed with NR under CS or HFJV under GA with available anesthesia records and CT fluoroscopic images were retrospectively reviewed; 13 and 33 treatment sessions, respectively, were identified. One anesthesiologist determined the choice of anesthesiologic technique independently. Surrogate measures of procedure technical difficulty--time duration, number of CT fluoroscopic acquisitions, and radiation dose required for applicator placement for each tumor--were compared between anesthesiologic techniques. The anesthesiologist time and complications were also compared. Parametric and nonparametric data were compared by Student independent-samples t test and χ(2) test, respectively. RESULTS: Patients treated with HFJV under GA had higher American Society of Anesthesiologists classifications (mean, 2.66 vs 2.23; P = .009) and smaller lung tumors (16.09 mm vs 27.38 mm; P = .001). The time duration (220.30 s vs 393.94 s; P = .008), number of CT fluoroscopic acquisitions (10.31 vs 19.13; P = .023), and radiation dose (60.22 mGy·cm vs 127.68 mGy·cm; P = .012) required for applicator placement were significantly lower in treatment sessions performed with HFJV under GA. There was no significant differences in anesthesiologist time (P = .20), rate of pneumothorax (P = .62), or number of pneumothoraces requiring active treatment (P = .19). CONCLUSIONS: HFJV under GA appears to reduce technical difficulty of CT-guided percutaneous applicator placement for lung tumor thermal ablations, with similar complication rates compared with treatment sessions performed with NR under CS. The technique is safe and may facilitate treatment of technically challenging tumors.

Percutaneous transtracheal ventilation in an obstructed airway model in post-apnoeic sheep.

BACKGROUND: Temporizing oxygenation by percutaneous transtracheal ventilation (PTV) is a recommended emergency technique in 'can't intubate, can't oxygenate' (CICO) situations. Barotrauma risk increases if expiration is obstructed. The Ventrain(®) is a new PTV device that assists expiration. Our aim was to compare key physiological outcomes after PTV with the Ventrain and the Manujet(®) in a large animal obstructed airway model. METHODS: Five anaesthetized sheep had post-apnoea PTV performed for 15 min using the Ventrain or Manujet with the proximal airway completely or critically obstructed, yielding four ventilation protocols per sheep. After apnoeic desaturation ([Formula: see text]70%), a 4 s rescue breath was delivered. Subsequent 2 s breaths were delivered whenever the airway pressure fell <10 cm H2O. RESULTS: Both devices achieved rapid re-oxygenation. There were marked device differences (Ventrain vs Manujet) in peak airway pressures with rescue (16 vs 40 cm H2O) breaths, minute ventilation (4.7 vs 0.1 litre min(-1)), and end-protocol pH (7.34 vs 7.01). There was no clinical evidence of barotrauma in any sheep after any ventilation protocol. An equilibration phase prevented large subatmospheric intrathoracic pressure development with Ventrain ventilation. CONCLUSIONS: The Ventrain provided stable oxygenation and effective ventilation at low airway pressures during emergency PTV in critically obstructed airways. The Manujet provided effective temporizing oxygenation in this situation with hypoventilation necessary to minimize barotrauma risk. The nature and extent of airway obstruction may not be known in a CICO emergency but an understanding of device differences may help inform optimal ventilation device and method selection.

Recovery and safety with prolonged high-frequency jet ventilation for catheter ablation of atrial fibrillation: A hospital registry study from a New England healthcare network.

STUDY OBJECTIVE: To investigate post-procedural recovery as well as peri-procedural respiratory and hemodynamic safety parameters with prolonged use of high-frequency jet ventilation (HFJV) versus conventional ventilation in patients undergoing catheter ablation for atrial fibrillation. DESIGN: Hospital registry study. SETTING: Tertiary academic teaching hospital in New England. PATIENTS: 1822 patients aged 18 years and older undergoing catheter ablation between January 2013 and June 2020. INTERVENTIONS: HFJV versus conventional mechanical ventilation. MEASUREMENTS: The primary outcome was post-anesthesia care unit (PACU) length of stay. In secondary analyses we assessed the effect of HFJV on intra-procedural hypoxemia, defined as the occurrence of peripheral hemoglobin oxygen saturation (SpO2) <90%, post-procedural respiratory complications (PRC) as well as intra-procedural hypocarbia and hypotension. Multivariable negative binomial and logistic regression analyses, adjusted for patient and procedural characteristics, were applied. MAIN RESULTS: 1157 patients (63%) received HFJV for a median (interquartile range [IQR]) duration of 307 (253-360) minutes. The median (IQR) length of stay in the PACU was 244 (172-370) minutes in patients who underwent ablation with conventional mechanical ventilation and 226 (163-361) minutes in patients receiving HFJV. In adjusted analyses, patients undergoing HFJV had a longer PACU length of stay (adjusted absolute difference: 37.7 min; 95% confidence interval [CI] 9.7-65.8; p = 0.008). There was a higher risk of intra-procedural hypocarbia (adjusted odds ratio [ORadj] 5.90; 95%CI 2.63-13.23; p < 0.001) and hypotension (ORadj 1.88; 95%CI 1.31-2.72; p = 0.001) in patients undergoing HFJV. No association was found between the use of HFJV and intra-procedural hypoxemia or PRC (p = 0.51, and p = 0.97, respectively). CONCLUSION: After confounder adjustment, HFJV for catheter ablation procedures for treatment of atrial fibrillation was associated with a longer length of stay in the PACU. It was further associated with an increased risk of intra-procedural abnormalities including abnormal carbon dioxide homeostasis, as well as intra-procedural arterial hypotension.

Airway trauma in a high patient volume academic cardiac electrophysiology laboratory center.

BACKGROUND: Providing anesthesia and managing airways in the electrophysiology suite can be challenging because of its unique setting outside of the conventional operating room. We report our experience of several cases of reported airway trauma including tongue and pharyngeal hematoma and vocal cord paralysis in this setting. METHODS: We analyzed all of the reported airway trauma cases between December 2009 and January 2011 in our cardiac electrophysiology laboratories and compared these cases with those without airway trauma. Data from 87 cases, including 16 cases with reported airway trauma (trauma group) and 71 cases without reported airway trauma from the same patient population pool at the same period (control group), were collected via review of medical records. RESULTS: Airway trauma was reported for 16 patients (0.7%) in 14 months among 2434 anesthetic cases. None of these patients had life-threatening airway obstruction. The avoidance of muscle relaxants during induction in patients with a body mass index less than 30 was found to be a significant risk factor for airway trauma (P = 0.04; odds ratio, 10; 95% confidence interval, 1.1-482). Tongue or soft tissue bite occurred in 2 cases where soft bite block was not used during cardioversion. No statistically significant difference was found between the trauma and the control groups for preprocedure anticoagulation, anticoagulation during the procedure, or reversal of heparin at the end of the procedure. CONCLUSIONS: The overall incidence of reported airway trauma was 0.7% in our study population. Tongue injury was the most common airway trauma. The cause seems to have been multifactorial; however, airway management without muscle relaxant emerged as a potential risk factor. Intubation with muscle relaxant is recommended, as is placing a soft bite block and ensuring no soft tissue is between the teeth before cardioversion.

Hazard of CO2 laser-induced airway fire in laryngeal surgery: experimental data of contributing factors.

In carbon dioxide (CO2) laser surgery of the larynx, the potentially dangerous combination of laser-induced heat in an oxygen-enriched atmosphere typically occurs when jet ventilation is used or due to an insufficiently blocked endotracheal tube. Until now, no limitations for safe oxygen concentrations or laser intervals have been established. The aim of this study was to investigate and quantify the factors that may contribute to an airway fire in laryngeal laser surgery. Fat, muscle and cartilage were irradiated with a CO2 laser at 2, 4, 6 and 8 W in five different oxygen concentrations with and without smoke exhaustion. The time to ignition was recorded for each different experimental setup. Fat burnt fastest, followed by cartilage and muscle. The elevation of laser energy or oxygen concentration reduced the time to inflammation of any tissue. The elevation of oxygen by 10 % increases the risk of inflammation more than the elevation of laser power by 2 W. Under smoke exhaustion, inflammation and burning occurred delayed or were even inhibited at lower oxygen concentrations. Lasing in more than 50 % oxygen is comparatively dangerous and can cause airway fire in less than 5 s, especially when laser energies of more than 5 W are applied. In equal or lower than 50 % oxygen, an irradiation interval of 5 s can be considered a comparatively safe time limit to prevent inflammation in laryngeal laser surgery. Smoke exhaustion should always be applied.

Quantitative assessment of atelectasis formation under high frequency jet ventilation during liver tumour ablation-A computer tomography study.

BACKGROUND: High frequency jet ventilation (HFJV) can be used to minimise sub-diaphragmal organ displacements. Treated patients are in a supine position, under general anaesthesia and fully muscle relaxed. These are factors that are known to contribute to the formation of atelectasis. The HFJV-catheter is inserted freely inside the endotracheal tube and the system is therefore open to atmospheric pressure. AIM: The aim of this study was to assess the formation of atelectasis over time during HFJV in patients undergoing liver tumour ablation under general anaesthesia. METHOD: In this observational study twenty-five patients were studied. Repeated computed tomography (CT) scans were taken at the start of HFJV and every 15 minutes thereafter up until 45 minutes. From the CT images, four lung compartments were defined: hyperinflated, normoinflated, poorly inflated and atelectatic areas. The extension of each lung compartment was expressed as a percentage of the total lung area. RESULT: Atelectasis at 30 minutes, 7.9% (SD 3.5, p = 0.002) and at 45 minutes 8,1% (SD 5.2, p = 0.024), was significantly higher compared to baseline 5.6% (SD 2.5). The amount of normoinflated lung volumes were unchanged over the period studied. Only a few minor perioperative respiratory adverse events were noted. CONCLUSION: Atelectasis during HFJV in stereotactic liver tumour ablation increased over the first 45 minutes but tended to stabilise with no impact on normoinflated lung volume. Using HFJV during stereotactic liver ablation is safe regarding formation of atelectasis.

Anesthetic management of patients undergoing pulmonary vein isolation for treatment of atrial fibrillation using high-frequency jet ventilation.

OBJECTIVES: The aim of this study was to describe anesthetic management and perioperative complications in patients undergoing pulmonary vein isolation for the treatment of atrial fibrillation under general anesthesia using high-frequency jet ventilation. The authors also identified variables associated with longer ablation times in this patient cohort. DESIGN: A retrospective observational study. SETTING: The electrophysiology laboratory in a major university hospital. PARTICIPANTS: One hundred eighty-eight consecutive patients undergoing pulmonary vein isolation under general anesthesia with high-frequency jet ventilation. INTERVENTIONS: High-frequency jet ventilation was used as the primary mode of ventilation under general anesthesia. MEASUREMENTS AND MAIN RESULTS: High-frequency jet ventilation was performed successfully throughout the ablation procedure in 175 cases of the study cohort. The remaining 13 patients had to be converted to conventional positive-pressure ventilation because of high PaCO(2) or low PaO(2) on arterial blood gas measurements. Variables associated with a shorter ablation time included a higher ejection fraction (p = 0.04) and case volume performed by each electrophysiologist in the study group (p = 0.001). CONCLUSIONS: High-frequency jet ventilation is generally a safe technique that can be used in catheter ablation treatment under general anesthesia.

Supraglottic jet ventilation in difficult airway management.

BACKGROUND: Supraglottic jet ventilation (SJV) via the "jet endotracheal tube" (JET) designed by Wei (WEI JET; Wei Medical LLC, Cherry Hill, NJ) provides adequate oxygenation and ventilation during direct laryngoscopy and tracheal intubation in animals. It has facilitated intubation in apneic pigs with a simulated difficult airway. OBJECTIVE: To report on the first clinical study to examine the efficacy of using SJV via the WEI JET, in combination with end-tidal CO(2) pressure (PetCO(2)) monitoring during SJV, in maintaining oxygenation during direct laryngoscopy, and in facilitating placement of the WEI JET, and comparing it to the standard intubation technique using a conventional endotracheal tube. The relative safety of using SJV via the WEI JET in airway management was also addressed to provide the foundation for a larger-scale clinical study using the WEI JET, to be carried out in the future. METHODS: Patients in the control group were intubated with a conventional endotracheal tube, and patients in the experimental group were intubated with a WEI JET. The effectiveness of SJV through a WEI JET in maintaining proper oxygenation, and the use of PetCO(2) monitoring to facilitate intubation, were studied and compared to the control group. Complications such as sore throat, laryngospasm, and barotrauma were recorded during the study and 24 h after extubation. RESULTS: In the WEI JET group, pulse oxygen saturation (SpO(2)) was 100% in all patients during intubation. No serious complications were detected, and the incidence of minor complications was comparable to the control group. Under PetCO(2) guidance, 100% of patients in the WEI JET group were intubated on the first attempt, compared to 30% of Grade III view patients in the control group, who required two attempts. CONCLUSION: Using the WEI JET with SJV provides adequate oxygenation during tracheal intubation in apneic patients for a prolonged period of time, with no difference in complications compared to the standard intubation technique. PetCO(2) monitoring facilitated intubation in patients with a Grade III glottis view.

Low Pressure Low Frequency Jet Ventilation: Techniques, Safety and Complications.

OBJECTIVE: Manual jet ventilation is a specialized oxygenation and ventilation technique that is not available in all facilities due to lack of technical familiarity and fear of complications. The objective is to review our center's 15 year experience with low pressure low frequency jet ventilation (LPLFJV). METHODS: Retrospective review of procedures utilizing LPLFJV from 2005 to 2019 were performed collecting patient demographic, surgery type and complications. Fisher exact test, Chi square, and t-test were used to determine statistical significance. RESULTS: Four hundred fifty-seven patients underwent a total of 891 microlaryngeal surgeries-279 cases for voice disorders, 179 for lesions, and 433 for airway stenosis. The peak jet pressure for all cases did not exceed 20 psi and average peak pressure for the last 100 procedures in this case series was 14.9 ± 4.6 psi. The average lowest oxygen saturation for all cases was 95% ± 0.6%. Brief intubation was required in 154 cases (17%). Surgical duration was significantly longer for cases requiring intubation P < .001. The need for intubation was not associated with smoking or cardiopulmonary disease, but was strongly associated with body mass index (BMI). Intubation rates were 7% for normal weight (BMI < 25, N = 216), 13% for overweight (BMI 25-30, N = 282), 24% for obese (BMI 30-40, N = 342), and 37% for morbidly obese (BMI > 40, N = 52) patients. Three patients developed respiratory distress in the recovery unit and 2 patients required intubation. CONCLUSION: LPLFJV assisted by intermittent endotracheal intubation is an exceedingly safe and effective intraoperative oxygenation and ventilationmodality for a broad variety of laryngeal procedure.

Feasibility, Safety, and Short-Term Outcomes of Transcatheter Patent Ductus Arteriosus Closure in Premature Infants on High-Frequency Jet Ventilation.

Background Prolonged exposure to a hemodynamically significant patent ductus arteriosus (PDA) is associated with major morbidity, particularly in infants born at <27 weeks' gestation. High-frequency jet ventilation (HFJV) is a standard of care at our center. There are no data about transcatheter PDA closure while on HFJV. The aim of this study was to assess the feasibility, safety, and outcomes of HFJV during transcatheter PDA closure. Methods and Results This is a retrospective cohort study of premature infants undergoing transcatheter device closure on HFJV. The primary outcome was successful device placement. Secondary outcomes included procedure time, fluoroscopy time and dose, time off unit, device complications, need for escalation in respiratory support, and 7-day survival. Subgroup comparative evaluation of patients managed with HFJV versus a small cohort of patients managed with conventional mechanical ventilation was performed. Thirty-eight patients were included in the study. Median age and median weight at PDA device closure for the HFJV cohort were 32 days (interquartile range, 25.25-42.0 days) and 1115 g (interquartile range, 885-1310 g), respectively. There was successful device placement in 100% of patients. There were no device complications noted. The time off unit and the procedure time were not significantly different between the HFJV group and the conventional ventilation group. Infants managed by HFJV had shorter median fluoroscopy times (4.5 versus 6.1 minutes; P<0.05) and no increased risk of adverse respiratory outcomes. Conclusions Transcatheter PDA closure in premature infants on HFJV is a safe and effective approach that does not compromise device placement success rate and does not lead to secondary complications.

High positive end-expiratory pressure during high-frequency jet ventilation improves oxygenation and ventilation in preterm lambs.

Increasing positive end-expiratory pressure (PEEP) is advocated to recruit alveoli during high-frequency jet ventilation (HFJV), but its effect on cardiopulmonary physiology and lung injury is poorly documented. We hypothesized that high PEEP would recruit alveoli and reduce lung injury but compromise pulmonary blood flow (PBF). Preterm lambs of anesthetized ewes were instrumented, intubated, and delivered by cesarean section after instillation of surfactant. HFJV was commenced with a PEEP of 5 cm H2O. Lambs were allocated randomly at delivery to remain on constant PEEP (PEEPconst, n = 6) or to recruitment via stepwise adjustments in PEEP (PEEPadj, n = 6) to 12 cm H2O then back to 8 cm H2O over the initial 60 min. PBF was measured continuously while ventilatory parameters and arterial blood gases were measured at intervals. At postmortem, in situ pressure-volume deflation curves were recorded, and bronchoalveolar lavage fluid and lung tissue were obtained to assess inflammation. PEEPadj lambs had lower pressure amplitude, fractional inspired oxygen concentration, oxygenation index, and PBF and more compliant lungs. Inflammatory markers were lower in the PEEPadj group. Adjusted PEEP during HFJV improves oxygenation and lung compliance and reduces ventilator requirements despite reducing pulmonary perfusion.

CT-guided navigation of percutaneous hepatic and renal radiofrequency ablation under high-frequency jet ventilation: feasibility study.

PURPOSE: Computed tomography (CT)-guided navigation during percutaneous radiofrequency (RF) ablations of liver and kidney lesions is hampered by respiratory motion and time-dependent lesion conspicuity after contrast agent injection. Therefore, target immobilization by general anesthesia with high-frequency jet ventilation (HFJV) instead of conventional ventilation (CV) with repeated breath-holds may facilitate and speed up navigation of RF ablation probes. MATERIALS AND METHODS: Nineteen consecutive patients who underwent percutaneous RF ablation of liver (n = 9) or renal tumors (n = 10) with CT guidance under HFJV (n = 9) or CV (n = 10) were included. The choice of the anesthesiologic technique was left to the discretion of the interventionalist. Complexity of the intervention (ie, number of lesions ablated per session, conspicuity of the lesion on nonenhanced CT, and access pathway), volume of the ablated tissue, radiation exposure, and complications were compared between the HFJV and CV groups. RESULTS: In this feasibility study, a statistically significant radiation dose reduction (P < .05) was noted in the HFJV group compared with the CV group for liver and renal RF ablation. No complications were observed in the HFJV group, whereas renal subcapsular hematoma (n = 2) and pulmonary embolism (n = 1) occurred in the CV group. CONCLUSIONS: Percutaneous CT-guided navigation of RF ablation probes under HFJV is feasible and safe. It might be advantageous for the treatment of complex kidney and liver tumors, allowing less irradiation exposure to the patient and the interventional radiologist.

Transtracheal jet ventilation in 50 patients with severe airway compromise and stridor.

BACKGROUND: Management of the airway is difficult in patients with pharyngeal or laryngeal pathology caused by malignancy, extensive surgery, or radiotherapy scarring, particularly when undergoing pharyngolaryngeal surgery. Tracheal intubation, with or without fibreoptic guidance, is often impractical because of the severe glottic stenosis and primary tracheostomy under local anaesthesia has been the preferred technique. However, complication rates as high as 30% have been reported after primary tracheostomy and there is the potential for long-term morbidity. High-frequency jet ventilation (HFJV) has several advantages over other techniques in the management of the difficult airway and can be delivered by supraglottic and infraglottic routes. To date, no large series has described the use of transtracheal HFJV (TTHFJV) in adult patients with stridor and critical airway obstruction. METHODS: We report a prospective, descriptive audit of the safe use of TTHFJV in patients with severe airway compromise and stridor undergoing pharyngolaryngeal surgery (50 consecutive procedures in 44 patients). RESULTS: TTHFJV was successful in all 50 cases. There were no major complications and the incidence of minor complications was 20% with no subsequent morbidity. CONCLUSIONS: We attribute this low incidence to the use of an automated jet ventilator with airway pressure monitoring and control, and the alteration of ventilator parameters by an experienced anaesthetist.

[Anesthetic management in laryngotracheal surgery. High-frequency jet ventilation as strategy for ventilation during general anesthesia]. / Anästhesiologische Besonderheiten bei der laryngotrachealen Chirurgie.

During surgical procedures of the upper respiratory tract anesthesiologists and surgeons are in a kind of competition situation because of the close spatial relationship between the airway of the patient and the surgical area. Especially in laryngeal surgery the use of high-frequency jet ventilation (HFJV) offers an alternative to the endotracheal tube. During HFJV the ventilation gas is intermittently administered by an injector with a high frequency into the airway which is open to the outside. Exhalation occurs passively in the area nearby the wall of the airway cross-section. According to the availability of the technique and the indications jet ventilation can be implemented in an infraglottic, supraglottic, transtracheal or transluminal manner. To exert influence on gas exchange of the patient the respiratory rate, driving pressure, oxygen concentration and inspiration time can be changed according to the needs. Severe tracheal stenosis, risk of excessive bleeding during the procedure, patients at risk for aspiration and exacerbation of lung diseases are depicted as contraindications for HFJV. Complications under HFJV are rare despite the limited conditions for monitoring gas exchange and mechanics of ventilation in contrast to conventional ventilation. A particular challenge for the anesthesiologist is the use of HFJV during laryngeal laser surgery.