The use of high-frequency jet ventilation for out of operating room anesthesia

Jet Ventilation Reduces Coronary Sinus Movement in Patients Undergoing Atrial Fibrillation Ablation: An Observational Crossover Study

BACKGROUND

One of the reasons that high-frequency jet ventilation (HFJV) is used is due to the near immobility of thoracic structures. However, no study has quantified the movements of cardiac structures during HFJV compared with normal mechanical ventilation.

METHODS

After ethical approval and written informed consent, we included 21 patients scheduled for atrial fibrillation ablation in this prospective crossover study. Each patient was ventilated with both normal mechanical ventilation and HFJV. During each ventilation mode, displacements of the cardiac structure were measured by the EnSite Precision mapping system using a catheter placed in the coronary sinus.

RESULTS

The median [Q1-Q4] displacement was 2.0 [0.6-2.8] mm during HFJV and 10.5 [9.3-13.0] mm during conventional ventilation (p < 0.000001).

CONCLUSION

This study quantifies the minimal movement of cardiac structures during HFJV compared to standard mechanical ventilation.

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.

Safety and Efficacy of a Novel Approach to Pulmonary Vein Isolation Using Prolonged Apneic Oxygenation

BACKGROUND

Improved ablation catheter-tissue contact results in more effective ablation lesions. Respiratory motion causes catheter instability, which impacts durable pulmonary vein isolation (PVI).

OBJECTIVES

This study sought to evaluate the safety and efficacy of a novel ablation strategy involving prolonged periods of apneic oxygenation during PVI.

METHODS

We conducted a multicenter, prospective controlled study of 128 patients (mean age 63 ± 11 years; 37% women) with paroxysmal atrial fibrillation undergoing PVI. Patients underwent PVI under general anesthesia using serial 4-minute runs of apneic oxygenation (apnea group; n = 64) or using standard ventilation settings (control group; n = 64). Procedural data, arterial blood gas samples, catheter position coordinates, and ablation lesion characteristics were collected.

RESULTS

Baseline characteristics between the 2 groups were similar. Catheter stability was significantly improved in the apnea group, as reflected by a decreased mean catheter displacement (1.55 ± 0.97 mm vs 2.25 ± 1.13 mm; P < 0.001) and contact force SD (4.9 ± 1.1 g vs 5.2 ± 1.5 g; P = 0.046). The percentage of lesions with a mean catheter displacement >2 mm was significantly lower in the apnea group (22% vs 44%; P < 0.001). Compared with the control group, the total ablation time to achieve PVI was reduced in the apnea group (18.8 ± 6.9 minutes vs 23.4 ± 7.8 minutes; P = 0.001). There were similar rates of first-pass PVI, acute PV reconnections and dormant PV reconnections between the two groups.

CONCLUSIONS

A novel strategy of performing complete PVI during apneic oxygenation results in improved catheter stability and decreased ablation times without adverse events. (Radiofrequency Ablation of Atrial Fibrillation Under Apnea; NCT04170894).

Utility of High-frequency Jet Ventilation in Atrial Fibrillation Ablation

Atrial fibrillation (AF) is the most common clinically significant arrhythmia that causes major morbidity and mortality. Catheter ablation focusing on pulmonary vein isolation is increasingly used for the treatment of symptomatic AF. Advances in ablation technologies and improved imaging and mapping have enhanced treatment efficiency but only modestly improved the efficacy. Another-but less commonly used-technology that can have a favorable impact involves enhancing the catheter-tissue contact by manipulating respiration to promote improved catheter stability and optimal contact. High-frequency jet ventilation (HFJV) is a mode of ventilation that can reduce respiratory movements to almost apneic conditions. In this review article, we aimed to highlight different studies, review the current literature regarding the utility of HFJV in AF ablation, and discuss the safety and efficacy of this approach relative to that of conventional ventilation.

High-Frequency Jet Ventilation in the Prone Position to Facilitate Cryoablation of a Peridiaphragmatic Pulmonary Neoplasm: A Case Report

Percutaneous cryoablation of pulmonary tumors at the posterior lung base is challenging due to diaphragmatic motion and the requirement for prone positioning. High-frequency jet ventilation allows oxygenation and ventilation with minimal diaphragmatic movement. In this case report, we describe the use of high-frequency jet ventilation in the prone position to facilitate the cryoablation of a peridiaphragmatic pulmonary neoplasm.

Embolisation of pulmonary arteriovenous malformations using high-frequency jet ventilation: benefits of minimising respiratory motion

Background

To evaluate patient radiation dose and procedural duration recorded during pulmonary arteriovenous malformation (PAVM) embolisation performed using high-frequency jet ventilation (HFJV) as compared with conventional intermittent positive pressure ventilation (IPPV)

Methods

Patients undergoing PAVM embolisation with HFJV assistance after April 2017 were retrospectively identified as group A, and those treated with IPPV before April 2017 as group B. Primary outcomes were patient radiation dose and procedural duration between groups A and B. Secondary outcomes were difference in diaphragmatic excursion between groups A and B, in group A with/without HFJ assistance, technical/clinical success, and complications.

Results

Twelve PAVMs were embolised in 5 patients from group A, and 15 PAVMs in 10 patients from group B. Mean patient radiation was significantly lower in group A than in group B (54,307 ± 33,823 mGy cm² [mean ± standard deviation] versus 100,704 ± 43,930 mGy cm²; p = 0.022). Procedural duration was 33.4 ± 16.1 min in group A versus 57.4 ± 14.9 min in group B (p = 0.062). Diaphragmatic excursion was significantly lower in group A (1.3 ± 0.4 mm) than in group B (19.7 ± 5.2 mm; p < 0.001) and lower with near statistical significance in group A with HFJV than without HFJV (1.3 ± 0.4 mm versus 10.9 ± 3.1 mm; p = 0.062). Technical and clinical success was 100% in both groups, without relevant complications.

Conclusion

HFJV-assisted PAVM embolisation is a safe, feasible technique resulting in reduced patient radiation doses and procedural time.

New trends in interventional pulmonology

PURPOSE OF REVIEW

As the field of interventional pulmonology continues to expand and develop at a rapid pace, anesthesiologists are increasingly called upon to provide well tolerated anesthetic care during these procedures. These patients may not be candidates for surgical treatment and often have multiple comorbidities. It is important for anesthesiologists to familiarize themselves with these procedures and their associated risks and complications.

RECENT FINDINGS

The scope of the interventional pulmonologist's practice is varied and includes both diagnostic and therapeutic procedures. Bronchial thermoplasty is now offered as endoscopic treatment of severe asthma. Endobronchial lung volume reduction procedures are currently undergoing clinical trials and may become more commonplace. Interventional pulmonologists are performing medical thoracoscopy for the treatment and diagnosis of pleural disorders. Interventional radiologists are performing complex pulmonary procedures, often requiring anesthesia.

SUMMARY

The review summarizes the procedures now commonly performed by interventional pulmonologists and interventional radiologists. It discusses the anesthetic considerations for and common complications of these procedures to prepare anesthesiologists to safely care for these patients. Investigational techniques are also described.

High-Frequency Jet Ventilation During Cryoablation of Small Renal Tumours

AIM

To evaluate the effect of high-frequency jet ventilation (HFJV) in place of standard intermittent positive-pressure ventilation (IPPV) on procedure duration, patient radiation dose, complication rates, and outcomes during CT-guided cryoablation of small renal tumours.

MATERIALS AND METHODS

One hundred consecutive CT-guided cryoablation procedures to treat small renal tumours under general anaesthesia were evaluated-50 with standard IPPV and 50 after the introduction of HFJV as standard practice. Anaesthesia and procedural times, ionising radiation dose, complications, and 1-month post-treatment outcomes were collected.

RESULTS

HFJV was feasible and safe in all cases. Mean procedure time and total anaesthetic time were shorter with HFJV (p = <0.0001). The number of required CT acquisitions (p = 0.0002) and total procedure patient radiation dose (p = 0.0027) were also lower in the HFJV group compared with the IPPV group. There were a total of four complications of Clavien-Dindo classification 3 or above-three in the IPPV group and one in the HFJV group. At 1-month follow-up, two cases (both in the IPPV group) demonstrated subtotal treatment. Both cases were subsequently successfully retreated with cryoablation.

CONCLUSION

By reducing target tumour motion during CT-guided renal cryoablation, HFJV can reduce procedure times and exposure to ionising radiation. HFJV provides an important adjunct to complex image-guided interventions, with potential to improve safety and treatment outcomes.

High frequency jet ventilation for motion management during ablation procedures, a narrative review

BACKGROUND

High frequency jet ventilation (HFJV) is a method of ventilation that has gained renewed interest over the recent years as it can reduce organ movement to near static conditions, thus enhancing surgical precision in minimal invasive procedures, for example, ablation procedures for atrial fibrillation and solid organ tumours. The aim of this review was to create a summary of the current evidence concerning the clinical use of HFJV for ablative procedures.

METHOD

PubMed was searched for the key words high frequency ventilation and ablation January 1990-December 2016.

RESULT

The search initially identified 34 papers, 14 met the inclusion criteria. Articles in other languages than English (n = 1), comments regarding other articles (n = 4) and articles that did not include HFJV or ablative procedures (n = 15) were excluded. Two articles were added from references in papers included from the primary search. Sixteen studies were finally included in the review; four updates/reviews and 12 papers with results from studies of HFJV on humans, with a total of 889 patients; 498 patients ventilated with HFJV and 391 controls. There were no randomised studies. The overall scientific quality of the studies was low.

CONCLUSION

There is a lack of well-designed studies evaluating HFJV during ablation procedures. The available information, while sparse, supports the effect of less tissue movement, resulting in better surgical precision and outcome; such as shorter procedural time, fewer shock waves (ESWL) and less recurrence of atrial fibrillation. Randomised controlled studies are needed in this promising area of research to prove its superiority to standard ventilation.

Navigated Percutaneous Lung Ablation under High-Frequency Jet Ventilation of a Metastasis from a Wilms' Tumour: A Paediatric Case Report

This is a case report of microwave energy being used to ablate an inoperable metastasis of a Wilms’ tumour in a 6-year-old boy using state-of-the-art navigated computed tomography targeting and high-frequency jet ventilation to reduce organ displacement and the potential risk of procedure-related pneumothorax. After the ablation, the young boy had high-dose chemotherapy followed by an autologous stem cell transplantation with rapid reduction of three recurrent right-sided lung metastases.

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.