High frequency jet ventilator ‒ a new approach in the management of anesthesia for pediatric cardiac Magnetic Resonance Imaging: case series / Ventilação a jato de alta frequência - uma nova abordagem no manejo da anestesia para ressonância magnética em cardiologia pediátrica: série de casos

Abstract Background and objectives: Cardiac Magnetic Resonance Imaging (MRI) is a technique used for evaluation of children with congenital heart diseases. General anesthesia ensures immobility, particularly in uncooperative patients. However, chest wall movements can limit good quality scans. Prolonged apnea may be necessary to decrease respiratory motion artefacts, potentially leading to hypoxemia and other adverse events. The use of a high frequency jet ventilator may be a solution avoiding chest wall movements. Case report: We report four cases of pediatric patients, ASA II, aged between 4 and 15 years-old, scheduled for cardiac MRI. General anesthesia was proposed and parental informed consent was obtained. After general anesthesia was induced, an uncuffed endotracheal tube was inserted. Then, a 7Fr × 40 cm catheter was placed through the endotracheal tube. The proximal outlet of the catheter was attached through a connecting tube to a high frequency jet ventilator (Monsoon III®, Acutronic Medical Systems). Good quality MRI images were obtained. At the end of the procedures, we observed increased salivation and increased end-tidal CO2 (60-70 mmHg), in all patients. The patients were extubated after normocapnia was achieved and neuromuscular blockade reversed. Following appropriate recovery time, the four children were discharged home the same day. Conclusions: This case series demonstrates that the use of a high frequency jet ventilator for cardiac MRI was feasible, safe, providing good quality cardiac imaging and avoiding anesthesia personnel to be inside the hazardous environment of MRI room. Future studies are needed to confirm its safety and efficiency in pediatric patients.

Resumo Justificativa e objetivos: A ressonância magnética (RM) cardíaca é uma técnica usada na avaliação de crianças com cardiopatias congênitas. A anestesia geral garante imobilidade, especialmente em pacientes não cooperadores, porém os movimentos da parede torácica podem limitar a boa qualidade dos exames. A apneia prolongada pode ser necessária para diminuir os artefatos do movimento respiratório, potencialmente levando à hipoxemia e outros eventos adversos. O uso de ventilação a jato de alta frequência pode ser uma solução para evitar os movimentos da parede torácica. Relato de caso: Relatamos quatro casos de pacientes pediátricos, ASA II, entre 4-15 anos, programados para ressonância magnética cardíaca. Uma anestesia geral foi proposta e assinaturas em termo de consentimento livre e esclarecido foram obtidas dos pais. Após a indução da anestesia geral, um tubo endotraqueal sem balonete foi inserido. Em seguida, um cateter de 7Fr × 40 cm foi inserido através do tubo endotraqueal. A saída proximal do cateter foi conectada, mediante um tubo conector, a um sistema de ventilação a jato de alta frequência (Monsoon III®, Acutronic Medical Systems). Imagens de ressonância magnética de boa qualidade foram obtidas. No fim dos procedimentos, observamos aumento tanto de salivação quanto de CO2 expirado (60-70 mmHg) em todos os pacientes. Os pacientes foram extubados após a obtenção de normocapnia e reversão do bloqueio neuromuscular. Após o tempo de recuperação apropriado, as quatro crianças receberam alta no mesmo dia. Conclusões: Esta série de casos demonstra que o uso de um sistema de ventilação a jato de alta frequência para ressonância magnética cardíaca é viável e seguro, além de fornecer imagens cardíacas de boa qualidade e evitar a presença da equipe de anestesia dentro do ambiente de risco da sala de ressonância magnética. Estudos futuros são necessários para confirmar sua segurança e eficiência em pacientes pediátricos.

Ventilación jet durante microcirugía de múltiples mixomas laríngeos en paciente con vía respiratoria anatómicamente difícil / Jet ventilation during microsurgery of multiple laryngeal myxomas in a patient with anatomically difficult respiratory airway

Introducción: La microcirugía de laringe incluye el dilema de un campo quirúrgico que coincide espacialmente con el del acceso a la vía respiratoria del paciente. Los mixomas, sobre todo numerosos y supra-infraglóticos, representan un reto terapéutico. Si aunado a este hecho, el paciente presenta una vía respiratoria anatómicamente difícil, la fórmula de la catástrofe sólo precisa mezclarlos con un plan de ventilación convencional. En este caso, la ventilación jet puede ser la alternativa para evitar una situación de desastre. Objetivo: Describir la secuencia de hechos y los resultados al aplicar por primera vez en el país la ventilación jet vía transcricotiroidea. Caso clínico: Ante el fracaso previo de una intervención mediante un método tradicional de ventilación, en una segunda intención para exéresis de múltiples mixomas laríngeos en una paciente con vía respiratoria anatómicamente difícil, después de obtener su consentimiento informado, se procedió a anestesiar y obtener un acceso transcricotiroideo a la vía respiratoria, para ventilar con flujos jet a través de un trocar 16G. La intervención, pensada para 15 min, se extendió durante 90 sin complicaciones ventilatorias o de oxigenación. La paciente fue dada de alta sin secuelas. Conclusiones: Aplicar ventilación jet vía transcricotiroidea fue oportuno, seguro y efectivo. Las complicaciones cardiovasculares menores fueron fácilmente controlables. Se usó por primera vez la ventilación jet transcricotiroidea en el país. Este resultado estimula la asimilación de las tecnologías de ventilación jet en contextos electivos o emergentes, como el desafío de una vía respiratoria anatómicamente difícil(AU)

Introduction: The larynx microsurgery involves the dilemma of a surgical field that coincides spatially with that of access to the patient's airway. Myxomas, especially numerous and supra/subglottic, represent a therapeutic challenge. If together with this fact, the patient presents an anatomically difficult airway, the formula for the catastrophe just needs to mix both with a conventional ventilation plan. In this case, jet ventilation can be the choice to avoid a disaster situation. Objective: To describe the sequence of events and the outcomes when transcricotyroid jet ventilation was applied for the first time in the country. Clinical case: In the face of previous failure of an intervention using a traditional method of ventilation, in a second intention for exeresis of multiple laryngeal myxomas in a patient with anatomically difficult airway, after obtaining her informed consent, we proceeded to anesthetize to obtain a transcricothyroid access to the respiratory tract, to ventilate with jet flows through a 16G trocar. The intervention, planned for 15 min, was extended for 90 minutes without ventilatory or oxygenation complications. The patient was discharged without sequelae. Conclusions: Transcricotyroid jet ventilation was timely, safe and effective. Minor cardiovascular complications were easily controllable. Transcricotyroid jet ventilation was used for the first time in the country. This outcome stimulates the assimilation of jet ventilation technologies in elective or emerging contexts, such as the challenge of an anatomically difficult airway(AU)

Use of a trans-tracheal rapid insufflation of oxygen device in a “cannot intubate, cannot oxygenate” scenario in a parturient: a case report / 대한마취과학회지

BACKGROUND: The trans-tracheal rapid insufflation of oxygen (TRIO) device is less commonly used and is an alternative to trans-tracheal jet ventilation for maintaining oxygenation in a “cannot intubate, cannot oxygenate” (CICO) scenario. CASE: We report the successful use of this device to maintain oxygenation after jet ventilator failure in a parturient who presented with the CICO scenario during the procedure for excision of laryngeal papilloma. CONCLUSIONS: A stepwise approach to the airway plan and preparation for an event of failure is essential for good materno-fetal outcomes. The TRIO device may result in inadequate ventilation that can lead to hypercarbia and respiratory acidosis. Hence, it should only be used as a temporizing measure before a definitive airway can be secured.

Seguridad y efectividad de la ventilación a chorro con frecuencias ventilatorias convencionales para microcirugía laríngea electiva / Safety and effectiveness of jet ventilation with conventional ventilatory frequencies for elective microlaryngeal surgery

Introducción: La ventilación al paciente durante la microcirugía laríngea confronta varios problemas. La ventilación a chorro tipo jet con frecuencias ventilatorias convencionales permite usar catéteres endotraqueales de pequeño diámetro para aportar volúmenes adecuados de oxígeno y proporciona mejores condiciones operatorias que el método tradicional. Objetivo: Evaluar la seguridad y efectividad de la ventilación jet con frecuencias ventilatorias convencionales para microcirugía laríngea electiva en comparación con la ventilación convencional. Métodos: Se realizó un estudio comparativo, a simple ciego, aleatorizado y paralelo. Se trabajó con un prototipo de dispositivo de ventilación jet con permiso de uso excepcional en seres humanos (autorización excepcional No: 004/17 para realización de estudio piloto, con fecha 2 de agosto de 2017, conferido por el CECMED). Se utilizó un grupo estudio de 45 pacientes (grupo E) y se comparó con un grupo control (grupo C) de 15 pacientes ventilados mediante el método tradicional. Resultados: La oxigenación resultó superior dentro del grupo E. El grupo C requirió eventualmente de extubación, apnea transitoria y reintubación, lo que repercutió en contra de la integridad anatomofisiológica de los pacientes, del campo operatorio y la docencia. Fue evidente una mayor estabilidad hemodinámica entre los sujetos del grupo E. Las presiones intrapulmonares producidas por la ventilación jet no provocaron lesiones ni repercusión clínica evidentes. Conclusiones: Aplicar la ventilación a chorro con frecuencias ventilatorias convencionales fue seguro y efectivo. Por primera vez se obtienen experiencias de utilización de un método de ventilación jet en el país. El grupo en el que se aplicó la ventilación convencional sufrió complicaciones más frecuentes y peligrosas. Es necesario asimilar las tecnologías de ventilación jet para elevar la calidad de la atención médica en tiempos de paz, de guerra o desastres, en contextos electivos, o emergentes como el desafío de una vía respiratoria difícil(AU)

Introduction: Ventilation to the patient during microlaryngeal surgery confronts several problems. Jet ventilation with conventional ventilatory frequencies allows the use of small diameter endotracheal catheters to provide adequate oxygen volumes and provide better operating conditions than the traditional method. Objective: To evaluate the safety and effectiveness of jet ventilation with conventional ventilatory frequencies for elective microlaryngeal surgery in comparison to conventional ventilation. Methods: A comparative, single-blind, randomized and parallel study was performed. It was used a prototype of jet ventilation device with an exceptional use permit in humans (exceptional authorization No: 004/17 for conducting a pilot study, dated August 2, 2017, conferred by the CECMED). A study group of 45 patients (group E) was used and compared with a control group (group C) of 15 patients using the traditional ventilation method. Results: Oxygenation was higher in group E. Group C eventually required extubation, transitory apnea and reintubation, which impacted against the anatomophysiological integrity of patients, the operative field and teaching. A greater hemodynamic stability was evident among the subjects of group E. The intrapulmonary pressures produced by jet ventilation did not cause obvious injuries or clinical repercussions. Conclusions: Applying jet ventilation with conventional ventilatory frequencies was safe and effective. For the first time, experiences of using a jet ventilation method in the country were obtained. The group in which conventional ventilation was applied suffered more frequent and dangerous complications. It is necessary to assimilate jet ventilation´s technologies to raise the quality of medical attention in times of peace, war or disasters, in elective or emerging contexts as the challenge of a difficult airway(AU)

Effects of penehyclidine hydrochloride combined with unilateral high-frequency jet ventilation on pulmonary function and inflammatory response during one-lung ventilation in patients with chronic obstructive pulmonary disease / 中华麻醉学杂志

Objective To evaluate the effects of penehyclidine hydrochloride (PHCD) combined with high-frequency jet ventilation (HFJV) of the operated lungs on pulmonary function and inflammatory response during one-lung ventilation (OLV) in patients with chronic obstructive pulmonary disease (COPD).Methods Sixty American Society of Anesthesiologists physical status Ⅱ or Ⅲ patients of both sexes with COPD,aged 40-64 yr,with body mass index of 17-26 kg/m2,scheduled for elective video-assisted thoracoscopic surgery under general anesthesia,were divided into 4 groups (n =15 each) using a random number table method:conventional group (group C),PHCD group (group P),HFJV group (group H) and PHCD combined with HFJV group (group PH).After induction of anesthesia,the patients were intubated with a double-lumen tube and then mechanically ventilated,with inspired oxygen concentration 100％,oxygen flow rate 2 L/min,tidal volume 6-8 ml/kg,respiratory rate 10-14 breaths/min,and respiratory rate was set at 12-16 breaths/min and PETCO2 was maintained at 40-45 mmHg during OLV.PHCD 0.01 mg/kg was intravenously injected before intubation in P and PH groups.The ventilation mode was changed to OLV after beginning of skin incision in each group.Ventilation of the lung on the operated side was performed by means of HFJV (driving pressure 0.5 kg/cm2) during OLV in P and PH groups.The pneumodynamic parameters such as airway peak pressure (Ppeak),airway plateau pressure (Pplat),airway resistance (Raw) and dynamic lung compliance (Cdyn) were monitored immediately before skin incision (T1) and at 60 and 120 min of OLV (T2,3).Arterial blood samples were obtained at T2 for blood gas analysis,and oxygenation index (OI),respiratory index (RI),physiologic dead space fraction (VD/Vr)and alveolar-arterial oxygen gradiant (A-aDO2) were calculated.Venous blood samples were drawn at T3 for determination of the serum concentrations of tumor necrosis factor-alpha (TNF-α),interleukin-6 (IL-6)and IL-8 by enzyme-linked immunosorbent assay.The occurrence of pulmonary complications was recorded within 72 h after operation.Results Compared with group C,the serum concentrations of TNF-α,IL-6 and IL-8,Ppeak,Pplat,Raw,RI,VD/VT,A-aDO2 and incidence of pulmonary complications were significantly decreased,and Cdyn and OI were increased in group P and group PH (P＜0.05),and the serum concentrations of TNF-α,IL-6 and IL-8,RI,VD/VT,A-aDO2 and incidence of pulmonary complications were significantly decreased,and OI was increased in group H (P＜0.05).Compared with group P or group H,the serum concentrations of TNF-α,IL-6 and IL-8,RI,VD/VT,A-aDO2 and incidence of pulmonary complications were significantly decreased,and OI was increased in group PH (P＜0.05).Conclusion PHCD combined with HFJV of the operated lung produces better efficacy in improving respiratory function,inhibiting inflammatory responses,reducing lung injury and is more helpful in improving prognosis than either alone in the patients with COPD.

The effects of High frequency two -way jet ventilation on the function respiratory and circulation of patients with Trachea and Carinal reconstruction / 中国基层医药

Objective To study the effects of High frequency two -way jet ventilation on the function respiratory and circulation of patients with Trachea and Carinal reconstruction.Methods Fifty patients with lung cancer,who were scheduled for elective trachea and carinal reconstruction,were intubated with double lumen tube following anesthesia induction and general anesthesia.High frequency ventilation was used on the healthful main bronchus during carinal reconstruction,a Hunsaker tube was inserted 3cm into the healthful main bronchus.HFTJV was applied with the respiratory rate of 120 /min,the ratio of inspiration and expiration E =1:1 and drive pressure of 0.2 -0.25Mpa.Blood gas analysis was made before the anesthesia,15 min following one -lung ventilation,10,20, 30 min following HFTJV and 15min following one -lung ventilation,respectively and monitor MAP,HR,SpO2 , PetCO2 .Results PaO2 in high frequency ventilation increased significantly compared with preoperative (78.0 ± 10.5)mmHg,was respectively (161.4 ±10.2)mmHg,(156.0 ±15.7)mmHg,(153.0 ±15.1)mmHg (P 0.05). Conclusion HFTJV is safe and reliable for Trachea and carinal reconstruction.

Protective effects of different modes of ventilation on lungs on operated side during one-lung ventilation in patients undergoing thoracic surgery / 中华麻醉学杂志

Objective To evaluate the protective effects of different modes of ventilation on the lungs on the operated side during one-lung ventilation (OLV ) in patients undergoing thoracic surgery .Methods Forty-five ASA physical status Ⅰ or Ⅱ patients of both sexes ,aged 45-64 yr ,weighing 65-80 kg ,were randomly divided into 3 groups (n=15 each) using a random number table :group A ,group B and group C .After induction of anesthesia ,the patients were intubated with double-lumen tube and OLV was performed .During OLV ,the lung on the operated side was collapsed naturally in group A ,positive pressure ventilation (FGF 2 L/min) was applied in the lung on the operated side in group B ,and high-frequency jet ventilation (frequency 100 beats/min ,driving pressure 0.5 kg/cm2 ) was used in the lung on the operated side in group C .Immediately after intubation (T0 ) , and at 1.5 h (T1 ) and 2 h (T2 ) of OLV ,blood samples were taken from the central vein and radial artery for determination of the serum interleukin-6 (IL-6 ) and IL-8 concentrations .The net release of IL-6 and IL-8 was calculated .Blood samples were taken from the radial artery at T0-2 for blood gas analysis and for determination of surfactant protein A (SP-A) concentration in the serum .Respiratory index (RI) was calculated .The non-cancer tissues 1.0 cm × 1.0 cm × 1.0 cm which were extracted from the lung cancer specimens were used for microscopic examination of the pathological changes of lungs which were scored .Results Compared with group A ,the net release of IL-6 and IL-8 ,serum SP-A concentration ,RI and pathological scores were significantly decreased at T1 ,2 in B and C groups ( P<0.05) .Compared with group B ,the serum SP-A concentration and RI were significantly decreased at T1 ,2 , and the net release of IL-6 was increased at T2 in group C ( P< 0.05 ) .Conclusion Continuous positive ventilation and high-frequency jet ventilation both can effectively protect the lungs on the operated side during OLV in patients undergoing thoracic surgery ,and the efficacy of high-frequency jet ventilation is better .

The effect of positive-end expiratory pressure on oxygenation during high frequency jet ventilation and conventional mechanical ventilation in the rabbit model of acute lung injury / 대한마취과학회지

BACKGROUND: The use of positive end expiratory pressure (PEEP) in patients with acute lung injury (ALI) improves arterial oxygenation by alleviating pulmonary shunting, helping the respiratory muscles to decrease the work of breathing, decreasing the rate of infiltrated and atelectatic tissues, and increasing functional residual capacity. In a rabbit model of saline lavage-induced ALI, we examined the effects of PEEP on gas exchange, hemodynamics, and oxygenation during high frequency jet ventilation (HFJV), and then compared these parameters with those during conventional mechanical ventilation (CMV). METHODS: Twelve rabbits underwent repeated saline lavage to create ALI. The animals were divided in 2 groups: 1) Group CMV (n = 6), and 2) Group HFJV (n = 6). In both groups, we applied 2 levels of PEEP (5 cmH2O and 10 cmH2O) and then measured the arterial blood gas, mixed venous blood gas, and hemodynamic parameters. RESULTS: With administration of PEEP of either 5 cmH2O or 10 cmH2O, the arterial oxygen content of both groups was increased, although without statistically significant differences between groups. On the contrary, the arterial carbon dioxide content was significantly decreased in the HFJV group, as compared with the CMV group, during the entire experiment. Furthermore, there was significant decreases in mean arterial pressures in both groups with a PEEP of 10 cmH2O. CONCLUSIONS: The application of PEEP in rabbits with ALI effectively improves oxygenation in either HFJV or CMV.

Effects of high-frequency jet ventilation on oxidative stress in patients during one lung ventilation / 中国医师进修杂志

Objective To determine the effects of high-frequency jet ventilation (HFJV) on oxidative stress in patients during one-lung ventilation (OLV). Methods Forty-five patients undergoing elective radical esophageal cancer resection were divided into three groups with 15 cases each by random digits table: two lung ventilation group ( group A), OLV group (group B), HFJV- OLV group ( group C, working pressure 1 kg/cm2 and frequency 100 times/min). Venous blood samples were taken before induction (T0),at30min (T1),90min (T2),150min (T3) after OLV and the end of operation (T4) for measuring serum superoxide dismutase(SOD),malondialdehyde (MDA) and nitric oxide (NO). Results SOD was lower at T2-T4 in group B[(47 ± 10), (37 ±9), (41 ±7) kU/L] and group C[(58 ± 12), (51 ± 11), (49 ± 9) kU/L] than those in group A [(78 ±8), (75 ±7), (79 ±6) kU/L](P＜ 0.05),and MDA and NO were lower at T1-T4 in group B and group C than that in group A(P＜ 0.05). SOD was higher at T3 in group C than that in group B (P ＜ 0.05), MDA at T1-T4 and NO at T2-T4 were lower in group C than those in group B (P ＜ 0.05). Conclusion HFJV can effectively decrease oxidative stress in patients during OLV.

High Frequency Jet Ventilation of One Lung using a Bronchial Blocker of Univent during Carinal Resection

Airway management during carinal resection should provide adequate ventilation and oxygenation as well as a good surgical field, but without complications such as barotraumas or aspiration. One method of airway management is high frequency jet ventilation (HFJV) of one lung or both lungs. We describe a patient undergoing carinal resection, who was managed with HFJV of one lung, using a de-ballooned bronchial blocker of a Univent tube without cardiopulmonary compromise. HFJV of one lung using a bronchial blocker of a Univent tube is a simple and safe method which does not need additional catheters to perform HFJV and enables the position of the stiffer bronchial blocker more stable in airway when employed during carinal resection.

The effects of inspiratory to expiratory ratio on ventilation and oxygenation during high frequency partial liquid ventilation in a rabbit model of acute lung injury / 대한마취과학회지

BACKGROUND: We examined the effects of varying inspiratory to expiratory (I : E) ratio on gas exchange and hemodynamics during high frequency partial liquid ventilation (HFPLV), a combination of high frequency ventilation (HFV) and partial liquid ventilation (PLV), in a rabbit model of acute lung injury. METHODS: Twelve rabbits treated with repeated saline lavage were divided into two groups. In the HFPL group (n = 6), 6 ml/kg of perfluorodecaline was administered through the endotracheal tube. Rabbits in this group and in the HFJ group (n = 6) were treated with high frequency jet ventilation (HFJV) at I : E ratios of 1 : 1, 1 : 2, and 1 : 3 for 15 minutes, and arterial blood gas, mixed venous blood gas and hemodynamic parameters were measured. RESULTS: We observed no significant respiratory and hemodynamic differences between the two groups. At an I : E ratio of 1 : 1, the PaO2 was significantly higher, and the shunt rate and PaCO2 were significantly lower in both groups, compared with I : E ratios of 1 : 2 and 1 : 3. Cardiac output at the 1 : 3 I : E ratio was significantly higher than at 1 : 1. CONCLUSIONS: These findings indicate that, in this model, a 1 : 1 I : E ratio was superior for oxygenation and ventilation than I : E ratios of 1 : 2 or 1 : 3, while having no detrimental effects on hemodynamics.

Transtracheal High-frequency Jet Ventilation using a Two-lumen Central Venous Catheter for Laryngomicrosurgery: A case report / 대한마취과학회지

A 33 year old female patient was scheduled for laser laryngomicrosurgery to remove a polyp arising from the posterior one third of the vocal cord.A double lumen central venous catheter was inserted through the cricothyroid membrane and transtracheal high frequency jet ventilation was performed via the distal lumen.The proximal lumen was connected to a capnography monitor, enabling breath by breath monitoring of PETCO2.The surgery was successfully completed, and the patient was discharged from the post anesthesia care unit (PACU) three hours after surgery without any complication.

The Effect of High Frequency Jet Ventilation with Partial Liquid Ventilation in Saline Lavaged Lung Injury in the Rabbit / 대한마취과학회지

BACKGROUND: Morbidity and mortality rates from acute respiratory failure remain noteworthy despite advances in conventional ventilatory techniques and improvements in supportive care. Repeated, the large tidal volume breaths during positive pressure mechanical ventilation lead to destruction of alveoli and pulmonary capillaries. Moreover, the overdistention of terminal lung units is considered as an important mechanism of ventilator induced lung injury. High frequency ventilation (HFV) is a technique involving a small tidal volume, and a higher than physiologic respiratory rate. Partial liquid ventilation (PLV), also known as perfluorocarbon-associated gas exchange, is a new technique for respiratory support. This study was designed to compare conventional mechanical ventilation (CMV) and high frequency jet ventilation (HFJV), in combination with PLV. METHODS: Twenty rabbits were anesthetized with xylazine, ketamine and vecuronium. We studied rabbits with lung injury induced by saline lavage. Animal were randomized into one of two treatment groups. Ventilator parameters included the following; CMV: FIO2 of 1.0, respiratory rate 20-30 breaths/min, I/E ratio 1 : 1; HFJV: respiratory rate 2 Hz, driving pressure 2psi. Animals were briefly disconnected from the ventilator and lungs were lavaged with warmed saline. This procedure was repeated until PaO2 < 100 mmHg. After one hour, we initiated the instillation of perfluorodecalin via an endotracheal tube. Baseline measurements were performed at 60 mins after the induction of anesthesia and repeated again at hour after the induction of lung injury, which included 30 mins of stabilization. After PFD instillation, data were recorded. RESULTS: All animals developed hypoxemia after the lung injury, but oxygenation improved significantly after perfluorodecalin instillation. The PLV-HFJV group showed a high pH and a low PaCO2. Mean arterial pressure, cardiac index and systemic vascular resistance was differed significantly. Although there were no qualitative histological differences between lungs ventilated with HFJV on CMV, the lower lobes of all PLV-treated animals were damaged less than the upper lobes, but without statical significance. CONCLUSIONS: PLV-HFJV produced a more efficient gas exchange than PLV-CMV. No significant difference was observed in the pulmonary pathologies of the groups.

Monitoring of PETCO2 during High Frequency Jet Ventilation for Laryngomicrosurgery

In general, PETCO2 is well correlated with PaCO2 during spontaneous and conventional mechanical ventilation in normal lungs. However, it is known that during high frequency jet ventilation, PETCO2 may underestimate PaCO2 because of inadequate washout of the anatomical dead space by a small tidal volume and the relatively slow response time of infrared CO2 analyzers. The validity of PETCO2 as a reflection of PaCO2 was assessed during HFJV in 40 patients undergoing laryngeal microsurgery. HFJV was applied through an injector inserted into the trachea 6 cm below the vocal cord. PETCO2 was obtained from a sampling line placed 2 cm below the injector. Both PETCO2 and PaCO2 were measured simultaneously after decreasing the frequency from 100 beats per minute to 15 beats per minute 10 and 20 minutes after the commencement of HFJV. There was a strong correlation (r = 0.955, P < 0.001) and a good correspondence between the mean PETCO2 and PaCO2 values with an average difference of 1.93 +/- 1.21 mmHg and a limit of agreement from -0.49 to 4.35 mmHg. It is suggested that the PETCO2 obtained following a decrease in the jet frequency during HFJV could closely reflect PaCO2.

Monitoring of Tracheal CO2 Tension during High Frequency Jet Ventilation for Laryngomicrosurgery / 대한마취과학회지

BACKGROUND: The monitoring of end-tidal CO2 tension (PETCO2) during high frequency jet ventilation (HFJV) has been unsatisfactory because of a small tidal volume and slow response time of CO2 analyser, although several authors have reported strategies of successful PETCO2 measurement during HFJV. The aim of this study was to assess the validity of tracheal CO2 tension (PtCO2) as a PaCO2 during HFJV. METHODS: We studied 24 patients undergoing laryngomicrosurgery during HFJV (rates: 100/min; I:E= 0.2; driving pressure: 0.25-0.35 MPa) through a 12 Fr. polyethylene injector placed 6-7 cm below the vocal cord. A gas sampling line was placed longitudinally against the injector and they were wrapped with aluminum foil. Continuous capnography was recorded during 20 minutes of HFJV. Every 5 minutes of HFJV, PtCO2 was obtained from the plateau value of CO2 wave after the stopping of JV and arterial blood gas analysis was done at 20 minutes of HFJV comparing PaCO2 to PtCO2. A Pearson's product moment correlation and regression analysis between PtCO2 and PaCO2 and the agreement between the two methods using Bland-Altman method were assessed. RESULTS: A regression analysis (R2=0.928) and a Pearson's product moment correlation (r=0.965, P<0.001) indicated a strong correlation of PtCO2 and PaCO2 during HFJV. The difference against a mean scatter diagram showed a relative good agreement between the two method (mean difference: 1.58 (SD 2.22) mmHg; limit of agreement: 2.86 and -6.02). CONCLUSIONS: PtCO2 obtained from a plateau of CO2 wave on capnography after interruption of HFJV can accurately reflect PaCO2 during HFJV in relative.

Treatment of Severe Meconium Aspiration Syndrome of Newborn Piglet by High Frequency Oscillatory Ventilation and Magnesium Sulphate / 中华围产医学杂志

Objective To evaluate the effect of high frequency oscillation ventilation (HFOV) and HFOV+ MgSO 4 on oxygenation, pulmonary and systemic arterial pressure, histologic alterations, and serum magnesium concentration in severe meconium aspiration syndrome(MAS) piglets with persistent pulmonary hypertension(PPH). Methods Newborn piglets were randomized to HFOV group( n =6), HFOV+MgSO 4 group( n =7) and control group( n =5). Piglets of HFOV group and HFOV+MgSO 4 group received an intratracheal a 20% suspension of human meconium. All piglets were given HFOV, Piglet of HFOV+MgSO 4 group was given MgSO 4 intravenously simultaneously. Cardiopulmonary functions, blood gases were monitored and serum magnesium concentration of piglets in HFOV+MgSO 4 group were measured by atomic absorption spectrophotometric assay. Results (1) HFOV and HFOV+ MgSO 4 treatment showed improved oxygenation in MAS model, PaO 2,a/APO 2 increased significantly and A-aDO 2?,Qs/Qt decreased significantly in HFOV group at 30 minute ( P

The Comparison of High Frequency Jet Ventilation and/or Conventional Mechanical Ventilation in Dogs / 대한마취과학회지

BACKGROUND: High frequency jet ventilation (HFJV) which can be replaced conventional mechanical ventilation (CMV) is another method in respiratory care. But, each one has weakness. This study was designed to determine whether combined HFJV with CMV is more prominent than HFJV on cardiopulmonary system. METHOD: Korean mongrel dogs (n=11) were induced with thiopental sodium 10 mg/Kg, intravenously. Tracheal intubation was performed, and CMV (respiratory rate 30/min, VT 10 ml/Kg, FiO2 1.0) was applied. After placement of monitors, arterial blood pressure (BP), heart rate (HR), central venous pressure (CVP), cardiac output (CO), pulmonary capillary wedge pressure (PCWP) were measured for control values on steady state of vital signs. Thereafter, HFJV was done using respiratory rate 120/min, inspiratory time 30 %, driving pressure 40 psi for 60 min (examed at time of 15, 30, 60 min), and then CMV was supplemented to HFJV using VT 10 ml/Kg, respiratory rate 8, 4, 2, 1, 0.5/min for 150 min (examed at time of 30, 60, 90, 120, 150 min). All values were measured and analyzed on suggested times according to the different ventilatory modes. RESULT: Arterial BP, HR, CO, CVP and PCWP were not changed significantly during the 60 minutes of HFJV. PaCO2 was increased significantly from 33+/-9 mmHg to 45+/-12 mmHg (p<0.05) and arterial pH was decreased significantly from 7.39+/-0.10 to 7.29+/-0.11 (p<0.05) after 60 minutes of HFJV. PaO2 was not changed for HFJV. Variables (BP, HR, CO, CVP and PCWP) were not changed significantly after combined HFJV with CMV at each respiratiry rates. Elevated PaCO2 at the 60 minutes of HFJV was normalized after combined HFJV with CMV at respiratory rate of 8, 4, 2, 1, 0.5/min. (p<0.05) and decreased pHa was also normalized (p<0.05) after combined HFJV with CMV at respiratory rate of 8, 4, 2, 1/min. PaO2 was not changed for the time which we combind HFJV with CMV. CONCLUSION: The combinded HFJV with CMV makes expected arterial oxygenation and prevents accumulation of arterial carbon dioxide without depressive effect on cardiovascular system, when tidal volume of CMV is 10 ml/Kg and the respiratory rate is above 1/minute. So, this study suggests that the combined HFJV with CMV may be applied to respiratory failure effectively.

The Change in Arterial Blood Gases during High Frequency Jet Ventilation via Weerda Distending Operating Laryngoscope / 대한이비인후과학회지

BACKGROUND: High Frequency Jet Ventilation(HFJV) has been applied safely to microlaryngeal endoscopic surgery(MES) via 14-16 gauge angiocath which is located around the carina. If HFJV is applied via the injection cannula of the Weerda distending operating laryngoscope(Weerda laryngoscope) which is located in 10cm above the vocal cord, complications associated with intubation and airway firing during laser surgery can be minimized. But increased dead space is expected. OBJECTIVES: We observed arterial blood gas changes after HFJV to determine how increased dead space influence arterial blood gases. MATERIALS AND METHODS: Eighteen patients scheduled for MES were studied. We analyzed arterial blood gases at just before HFJV, 5, 10, 15 and 20 minutes after HFJV and 15 minutes after postanesthetic recovery room(PAR) arrival. Complications were also evaluated via physical examination and chest X-ray films. RESULTS: 1) All arterial oxygen tensions during HFJV with 100% oxygen(we do not have exact inspired oxygen fraction because of Venturi effect.) were above 200 mmHg. 2) Arterial carbon dioxide tension at 5 and 10 minutes after HFJV were significantly(p<0.05) greater than arterial carbon dioxide tension before HFJV. Statistical analysis was not performed due to small number of case(N=4, 3) at 15 and 20 minutes after HFJV, but progressive increasing tendency of arterial carbon dioxide tension was observed. 3) Complications such as mild abdominal distension, hypercarbia and moderate mucosal dryness were observed. CONCLUSION: HFJV via the injection cannula of Weerda laryngoscope can be used with caution such as prevention of hypercarbia.

Total Intravenous Anesthesia for High Frequency Jet Ventilation in Laryngomicrosurgery / 대한마취과학회지

Total intravenous anesthesia(TIVA) is desirable technique for a number of reasons. The first is that it implies all the components of general anesthesia : hypnosis, amnesia, analgesia, and muscle relaxation by combination of several drugs and the lungs are ventilated with oxygen-enriched air. A combination of fentanyl-propofol were used as TIVA for laryngomicrosurgery (LMS) with high frequency jet ventilation(HFJV). 41 patients were studied. Glycopyrrolate was given 1 hour before anesthetic induction. Propofol 2 mg/kg was intravenously administered 1 minute after fentanyl 1.5 ug/kg intravenously injection for induction. Endotracheal intubation was performed after succinylcholine administration with internal diameter 4.0-6.0 mm LASER tube through oral cavity or 8 fr. polyethylene catheter through nasal airway. After then, HFJV was started with frequency 108-120 cycles/minute and driving pressure 2.0-2.5 kg/cm(2). The adequacy of ventilation was evaluated with arterial blood gas analysis. For maintenance a continuous propafol infusion of 10 mg/kg/hour was used for the first 10 minutes, followed by 8 mg/kg/hour for the next 10 minutes and 6 mg/kg/hour, thereafter. Continuous dripping of succinylcholine was used for muscle relaxation. The patients showed relatively stable hemodynamic status during procedure (Fig. 1). Two recovery times were as followed: the interval from cessation of infusion until opening eyes on command(4.90+/-3.41 min), and that until correct response to simple question (5.50+/-3.49 min). There was a correlation between total amount of propofol given to patients and recovery times(P<0.05)(Table 1). Interestingly. a group of patients weighed over 70 kg showed carbon dioxide retension on arterial blood gas analysis(Fig. 2). In conclusion, fentanyl-propofol cobination with muscle relaxant is proper regimen for TIVA in LMS with HFJV. More stable and better recovery are the main reasons. However, carbon dioxide retension should be consider to the patients weighed over 70 kg with the HFJV.

Feasibility of application of high frequency jet ventilation to trachea and carinal reconstruction / 中华麻醉学杂志

Objective To evaluate feasibility of high frequency jet ventilation (HFJV) during trachea and carinal reconstruction. Methods Ten patients with lung cancer ,scheduled for elective trachea and carinal reconstruction ,were intubated with double lumen tube following routine anesthesia induction. A HFJV tube (ID=3mm) was inserted 3cm into main bronchus. HFJV was applied ,with the respiratory rate of 120/min,I:E=1:2 and drive pressure of 0.15-1.20MPa, after cut off the main bronchus of the opposite side. Blood gas analysis was made before the operation, 15min following one-lung ventilation, 5, 10, 20 min following HFJV and 15min following one-lung ventilation,respectively.Results PaO 2 was significantly higher following HFJV than that one-lung ventilation (P