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.

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.

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.

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.

Clinical study for artificial ventilation combined continuous positive airway pressure with removal of tracheobronchial foreign bodies in children / 中国基层医药

Objective To observe the clinical effect of artificial ventilation combined continuous positive airway pressure(CPAP) with removal of tracheobronchial foreign bodies for children and to explore the possibility and security of the method. Methods 60 children with tracheobronchial foreign body, underwent total intravenous anesthesia ,were randomly divided into A group and B group. Each group had 30 cases. A group was given artificial ventilation with CPAP. The bronchofibroscope was connected to anesthesia machine with side hole after induction for 3 minutes,and high fresh gas flow(10 ～ 15L/min) was given to maintain continuous positive airway pressure. B group were given high frequency jet ventilation(HFJV) ,60 ～ 100 bpm. The mask ventilation was given in stand of bronchofibroscope when SpO2 ＜ 90% and until SpO2 improved. MAP, HR, ECG, SpO2, PaO2, PaCO2 were monitored and recorded at time points: T0 (entered operation room), T1 (beginning of bronchofibroscopy), T2 (5 min after bronchofibroscopy), T3 (10 min after bronchofibroscopy), T4 (end of operation). The side effects, the rate of fail to bronchofibroscopy and the rate of intubations after operation in two groups were observed and recorded. Results The HR of post-anesthesia in two groups significantly decreased than those at T0 (P ＜ 0.01), but no difference showed in HR between two groups(P ＞ 0.05). SpO2 and PaO2 of post-anesthesia in two groups significantly increased than those at T0 (P ＜0. 01) ,PaO2 at T1 ,T2 ,T3 in A group were significantly higher than those in B group(P ＜0.05). PaCO2 gradually increased after bronchofibroscopy in two groups ,and the values in A group was significantly lower than in B group(P ＜0.05 or 0. 01). There were no significant differences in the rates of fail to bronchofibroscopy and of intubations after operation between two groups, but the total number of B group was higher. Conclusion Artificial ventilation with CPAP for children with removal of tracheobronchial foreign bodies was safe and practical, and has a better controllability, a minor effect to respiratory function, deserve popularizing.

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.

Remifentanil,Propofol and High Frequency Jet Ventilation Used for Respiratory Tract Foreign Body Removal in Children / 医学研究杂志

Objective To investigate the clinical effect of combined use of remifentanil,propofol and high frequency jet ventilation for respiratory tract foreign body removal in children.Methods Fifty-two children undergoing respiratory tract foreign body removal operations were randomly divided into two groups: group A with remifentanil,propofol and high frequency jet ventilation(n=26),and group B with ketamine and sodium ?-hydroxybutrate(n=26).The changes of operation time,awaken time,vital signs and the incidence of intra/post-operative complications were observed.Results There was no significant differences in operation time,but awaken time in group A was significantly longer than that in group B(P

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.

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.

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

Effect of High Frequency Jet Ventilation alone or with Positive End Expiratory Pressure on the Arterial Oxygenation during One Lung Ventilation / 대한마취과학회지

BACKGROUND: Hypoxemia during one lung ventilation (OLV) may occur in spite of high inspired oxygen concentration. The purpose of this study was to evaluate the effect of highfrequency jet ventilation (HFJV) alone to the non-ventilated lung or in combination with 5 cmH2O of positive end expiratory pressure (PEEP) to the ventilated lung on arterial oxygenation (PaO2) during OLV for thoracic surgery. METHODS: After endotracheal intubation with double lumen tube, arterial blood gases were measured 20 minutes after stabilization had occurred following onset of OLV, HFJV, and HFJV with 5 cmH2O of PEEP. RESULT: The mean PaO2 during OLV was 257.5+/-81.7 mmHg, and application of HFJV alone or with PEEP resulted in a significant increase in PaO2 to 356.6+/-79.1 mmHg and 354.9+/-66.6 mmHg, respectively (p<0.001). Alveolar-arterial oxygen differences were significantly decreased as compared to OLV. CONCLUSION: Both HFJV alone or in combination with 5cmH2O of PEEP are effective to improve oxygenation during OLV.

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.

The Change of Arterial Blood Gas during High Frequency Jet Ventilation via 14 French Suction Catheter in Microlaryngeal Endoscopic Surgery / 대한마취과학회지

BACKGROUND: It is a routine practice that High Frequency Jet Ventilation (HFJV) is applied through a 14~16 gauge (about 12 French (Fr.)) angiocath. The 14 Fr. suction catheter which is similar to angiocath in its internal diameter is commonly available in the operating room. We evaluated the suction catheter as a carrier of HFJV in point of ventilation, oxygenation and operating field during HFJV at microlaryngeal endoscopic surgery (MES). METHODS: Fifteen adult patients undergoing HFJV via 14 Fr. suction catheter during MES were studied. Time-based arterial blood gas analyses were done before and after HFJV. The movement of operating field was examined using laryngoscopic examination by surgeon and anesthesiologist. We also evaluated complications such as abdominal distension, barotrauma and so on. RESULTS: The mean arterial oxygen tension was maintained above 250 mmHg all the time during HFJV. The mean carbon dioxide tension was less than 51 mmHg. There were no remarkable catheter movement and complications. CONCLUSION: The 14 Fr. suction catheter is a good replacement of angiocath. It provided good operating field, ventilation and oxygenation without complications.

The Effects of Combined High-Frequency Jet Ventilation and Conventional Mechanical Ventilation on Cardiovascular and Respiartory System with Pulmonary Edema Induced by Oleic Acid in Dogs / 대한마취과학회지

BACKGROUND: High-frequency jet ventilaion is considered a reliable technique for anesthesia and critical care including respiratory failure but there are adverse reactions such as carbon dioxide retension and dry of respiratory mucosa. The purpose of this study was to confirm the effects of combined high- frequency jet ventilation (HFJV) and converntional mechanical ventilation (CMV) on the cardiovascular system, arterial blood gases tension and mean airway pressure in 9 Korea mongrel dogs with pulmonary edema induced by oleic acid. METHODS: During CMV with 20 breaths/minute, 10 ml/kg of tidal volume and F1O2 1.0, parameers were evaluated (base line value). When pulmonary edema was developed, HFJV was applied initially with 120 breaths/minute, inspiratory time 30% and driving pressure 40 psi F1O2 1.0 for 60 minutes (control value) and thereafter simultaneous use of CMV was applied with the tidal volume of 10 ml/kg and each respiratory rate 8, 4, 2, 1, 0.5 per minute for 30 minutes. RESULTS: Combined application of HFJV and CMV (above repiratory rate 1 per minute) achieved the improvement of oxygenation and carbon dioxide elimination, and Paw was decreased without undesirable effects on cardiovascular system in case of the induced pulmonary edema. CONCUSIONS: From above results we recommanded that HFJV combined with CMV may be a useful method of treatment for respiratory failure.

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.