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.

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.

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

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

High Frequency Jet Ventilation during Laryngeal Microsurgery : Effect of Inspiration Time and Frequency on the Gas Exchange / 대한마취과학회지

High frequency jet ventilation(HFJV) administered through a thin catheter instead of a standard endotracheal tube provides improved operation field during laryngeal microsurgery. In this study, effect of changes in inspiration time and frequency on gas exchange was observed. Sixty five patients(ASA class 1-2) underwent laryngeal microsurgery were divided into 3 groups according to inspiration time(50%, 40% and 30%) and then subdivided into 3 groups according to frequency(3.3 Hz, 2.5 Hz and 1.7 Hz). Driving pressure was same in all groups(2.4 kg, cm). Anesthesia was induced with thiopental sodium, fentanyl and succinylcholine with 100% oxygen mask ventilation and maintained with intermittent intravenous anesthetics during jet ventilation via 10 Fr. catheter with 100% oxygen. Jet cannular was located 1 cm proximal to carina. Arterial blood gas analysis and hemodynamic data(blood pressure and heart rate) were measured at 0 minute(just after catheter intubated and jet ventilation started), 5 minute, 10 minute and after then, every 10 minutes. There was significant change in PaCO; by varing inspiration time but, no significant change by frequency except in group of 3.3 Hz at inspiration time 40% and 30%. Number of patients who showed in excess of 45 mmHg of PaCO2 at 20 minute were 2 out of 19, 9 out of 23 and 9 out of 23 in inspiration time 50%, 40% and 30%, respectively. In summary, HFJV via thin catheter located 1 cm proximal to carina during laryngeal microsurgery can be done safely with inspiration time 50% under good operation field at driving pressure 2.4 kg/cm and frequency 3.3, 2.5 and 1.7 Hz.

Inhalation Anesthesia with High Frequency Jet Ventilation / 대한마취과학회지

High frequency jet ventilation(HFJV) induces adequate gas exchange with tidal volume smaller than that of other conventional ventilation method. In critically ill patients, HFJV reduces the unwanted hemodynamic effects of conventional ventilation caused by the increase in intrathoracic pressure. But general anesthesia with jet ventilator has been dependent only on intravenous anesthetics. Therefore, this study was done to administer inhalation anesthetics(N2O, enflurane) during HFJV. This study was carried out from June 1992 to January 1993 in the 64 operated patients who beIonged to ASA class I, II in Chung Ang University Hospital The 22 patients using conventional ventilation were control group and the other 42 patients who had inhalation anesthesia by using HFJV were experimental group. In all patients, blood pressure and heart rate were checked on preinduction, postinductive 0, 5, 10, 15, 20, and 30 minutes. The result were as follows I) Systolic blood pressure was increased just on postinduction in both groups(P<0.05). It was decreased from postinductive 5 minutes to 30 minutes in control group, but there was no change in experimental group(P<0.05). 2) Diastolic blood pressure was increaeed just on postinduction in both groups(P<0.05). But it was increased from postinductive 5 minutes to 30 minutes in experimental group(P<0.05). 3) Mean blood pressure was increased just on postinduction in both groups(P<0.05). It was increased from postinductive 5 minutes to 15 minutes in control group and from postinductive 5 minutes to 30 minutes in experimental group(P<0.05). 4) Heart rate was increased just on postinduction and postinductive 5 minutes in control groupg <0.05), and increased from postinductive 0 minute to postinductive 30 minutes in experimental group(P<0.05). 5) pH was increased on postinductive 30 minutes compared to that of preinduction in both groups(P <0.05). 6) PaCO2 was more decreased on postinductive 30 minutes than preinduction in both groups (P<0.05), but there was no clinical significance. And PaO2 was increased at postinductive 30 minutes(P<0.05), which resulted from the increase of FiO2. As above results, inhalation anesthesia with HFJV is supposed to be useful if the difficulty of controlling the concentration of inhalation anesthetics and the contamination of operating room by expelled inhalation anesthetics were solved.

The Effects of Surfactant Therapy using High Frequency Jet Ventilation on Lung Lavaged Dogs / 대한마취과학회지

The effects of exogenous surfactant replacement therapy using high frequency jet ventilation (HFJV) on arterial blood gases changes, pulmonary and hemodynamic variables were observed in lungs lavaged dogs with saline. Lungs were lavaged repeatedly with warm physiological saline until PaO2 fall 100 mmHg level. Surfactant 50 mg/kg was administered in experimental group and saline was administered in control group intratracheally using HFJV. During administration of surfactant using HFJV, all the dogs were not hypoxemic and PaCO2 were within normal range. HFJV was done for 1 hour to make even distribution of the surfactant, After that, controlled mechanical ventilation of the initial condition was eontinued for 3 hours. 1n surfactant administered group, our results showed that significant PaO2 improvement were observed and maintained for 3 hours, bur no significant changes were observed in saline administered group. In this study, we suggest that the effects of exogenous pulmonary surfactant administered using HFJV on acute respiratory failure, induced by repeated lungs lavage with saline, were good and HFJV can be used a safe and effective method for the administration of the pulmonary surfactant.

Effect of Outflow Resistance on Airway Pressure during High Frequency Jet Ventilation / 대한마취과학회지

High frequency ventilation considerably reduces the risk of barotrauma due to low peak airway pressure compared to conventional mechanical ventilation. This risk, however, is also preaent with high frequency jet ventilation (HFJV) if excessive driving preasure are used and, above all if expiration is impeded. We investigated the effects of outflow resistance, which was varied by connecting different size of tube (ID 8.0, 7.5, 7.0, 6.5, 5.5, 5.0, 4.5, 4.0 mm), which was cut in 10 cm length, to the proximal site of endotracheal tube (ID 8.0 mm), which was inserted into the trachea of anesthetized dogs with a attached airway pressure monitoring catheter externally, in different driving pressure (2 kg/cm2, 1 kg/cm2) and frequency (100beats/min, 200beats/min) on the intra-airway preesure during HFJV. HFJV was performed with a catheter (diameter 2.5 mm) which was inaerted through endotracheal tube and located 1 cm proximal to the tip of endotracheal tube. Intra-airway pressure was acutely increased with the tube size of smaller than 5.5 mm in driving pressure 2 kg/cm2 and 5.0 mm in driving pressure 1 kg/cm2 compared to previous size of tube. 2 kg/cm2 of driving pressure showed significant higher airway pressure compared to 1 kg/cm in any size of tube. There was no difference in airway pressure by varing of frequency with same driving preasure. In summary, pulmonary barotrauma due to higher airway pressure may be occur if HFJV catheter occupied more than 25% of outflow tract area especially in higher driving pressure.