Special mechanical ventilation:heliox ventilation and partial liquid ventilation / 中国小儿急救医学

Neonatal mortality has been significantly decreased because of the development of neo-natal respiratory support techniques. Nevertheless,constant and high frequency ventilators have some limita-tions to solve all problems in neonatal respiratory failure. Special mechanical ventilation,mainly including he-liox and partial liquid ventilation,provides new respiratory support for newborn infants. The clinical signifi-cance of heliox and partial liquid ventilation need further investigation.

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.

The Effects of Perfluorocarbon on Respiratory Mechanics and Pulmonary Gas Exchange with Methacholine-induced Bronchoconstriction in Cats / 대한마취과학회지

BACKGROUND: Perfluorocarbon (PFC) liquids have high oxygen carrying capacity and relatively low surface tension allowing them to spread evenly through the diseased lung, especially in the case of adult respiratory distress syndrome. But few studies have demonstrated the effects of PFC on a bronchoconstriction model. The aim of this study was to investigate the effects of PFC on pulmonary mechanics and gas exchange in methacholine-induced bronchoconstricted cats using a flow interruption technique. METHODS: Twenty male cats were divided into four groups; control group (group C, n = 5), PFC group (group P, PFC 5 ml/kg, n = 5), methacholine group (group M, 25 microgram/kg/min, n = 5), PFC and methacholine group (group MP, n = 5). Respiratory pressure using a flow interruption technique was measured immediately after stabilizing the heart rate and blood pressure 0, and 15, 30 and 60 min after the start of the intratracheal administration of PFC and/or methacholine infusion, depending on the group. Arterial blood gas analysis was done to compare arterial partial oxygen pressure among the groups at the time of measuring the pressure values. The pressure data was transferred to a personal computer and analyzed using ANADAT software program. Respiratory, airway and tissue viscoelastic pressure were calculated. Statistical analysis was done by ANOVA and statistical significance was defined as P <0.05. RESULTS: Group M and MP showed significantly increased airway pressures compared with group C (P <0.05), but there was no difference among the groups in terms of viscoelastic pressure. Arterial blood gas analysis showed that group P and MP had lower arterial partial oxygen pressures than group C (P <0.05). CONCLUSIONS: This study demonstrates that the intratracheal administration of PFC in a bronchoconstriction cat model increases airway pressure more than tissue viscoelastic pressure, and decreased arterial oxygen partial pressure. We conclude that the intratrachel administration of PFC is not to be recommended in bronchoconstrictive situations.

Evaluation of Parameters of Gas Exchange During Partial Liquid Ventilation in Normal Rabbit Lung / 결핵

BACKGROUND: The opitmal ventilator setting during partial liquid ventilation(PLV) is controversial. This study investigated the effects of various gas exchange parameters during PLV in normal rabbit lungs in order to aid in the development of an optimal ventilator setting during PLV. METHODS: Seven New-Zealand white rabbits were ventilated in pressure-controlled mode with the following settings; tidal volume(VT) 8ml/kg, positive end-expiratory pressure(PEEP) 4cmH2O, inspiratory-to-expiratory ratio(I:E ratio) 1:2, fraction of inspired oxygen(F1O2) 1.0. The respiration rate(RR) was adjusted to keep PaCO2 between 35~45mmHg. The ventilator settings were changed every 30 min in the following sequence : (1) Baseline, as the basal ventilator setting, (2) Inverse ratio, I:E ratio 2:1, (3) high PEEP, adjust PEEP to achieve the same mean inspiratory pressure (MIP) as in the inverse ratio, (4) High VT, VT 15ml/kg, (5) high RR, the same minute ventilation(MV) as in the High VT. Subsequently, the same protocol was repeated after instilling 18ml/kg of perfluorodecalin for PLV. The parameters of gas exchange, lung mechanics, and hemodynamics were examined. RESULTS: (1) The gas ventilation(GV) group showed no significant changes in the PaO2 at all phases. The PaCO2 was lower and the pH was higher at the high VT and high RR phases(p<0.05). No significant changes in the lung mechnics and hemodynamics parameters were observed. (2) The baseline PaO2 for the PLV was 312+/-113mmHg. This was significantly lower when decreased compared to the baseline PaO2 for GV which was 504+/-81mmHg(p=0.001). During PLV, the PaO2 was significantly higher at the high PEEP(452+/-38mmHg) and high VT(461+/-53mmHg) phases compared with the baseline phase. However, it did not change significantly during the inverse I:E ratio or the high RR phases. (3) The PaCO2 was significantly lower at high VT and RR phases for both the GV and PLV. During the PLV, PaCO2 were significantly higher compared to the GV (p<0.05). (4) There were no important or significant changes in of baseline and high RR phases lung mechanics and hemodynamics parameters during the PLV. CONCLUSION: During PLV in the normal lung, adequate VT and PEEP are important for optimal oxygenation.

Treatment effect of partial liquid ventilation on pulmonary edema after seawater drowning in rabbits / 第二军医大学学报

Objective:To observe the effect of partial liquid ventilation (PLV) on gas exchange,pulmonary compliance and blood dynamics in the pulmonary edema rabbits after seawater drowning(PE-SWD). Methods:Totally 42 healthy male New Zealand rabbits were randomly allocated into 3 groups (n=14);each group was treated with various methods after PE-SWD model was established:PE group with no treatment,CMV group with conventional mechanical ventilation and positive end-expiratory pressure(PEEP),PLV group with CMV,PEEP and FDC.After being treated for 3 h,blood gases,pulmonary mechanics,hemodynamics,pulmonary histopathology and survival time were observed.Results:In PLV group,PaO 2 increased obviously and reached (262.84?64.33) mmHg (1 mmHg=0.133 kPa), airway pressure decreased by 23.4%,pulmonary static compliance increased by 31.3% and TNF-? decreased by 24.9%.HR and MAP showed no significant changes after treatment compared with PE group.Conclusion: Pulmonary gas exchange and compliance are improved significantly during PLV in the PE-SWD rabbits without obvious influence on hemodynamic status, although the survival time of PLV group is less than that of CMV group.

The effect of partial liquid ventilation on pulmonary tissue in rabbits with pulmonary edema following seawater drowning / 解放军医学杂志

Objective To observe the effect of partial liquid ventilation (PLV) and conventional mechanical ventilation(CMV) on gas exchange in lung injury due to pulmonary edema as a result of seawater drowning in rabbit. Methods Twenty-four healthy male new Zealand rabbits were randomly divided into three groups ( n =8). Pulmonary edema was produced in all rabbits by drowning in sea water. Rabbits of PE group received no treatment,that of CMV group were treated with conventional mechanical ventilation and PEEP,and that of PLV group with CMV,combined with PEEP and FDC. All rabbits were treated for 3 hours. Blood gases,TNF-?in plasma and pulmonary histopathology were determined during the experiment. Results In PLV group,PaO_2 was increased obviously,inflammatory exudate was reduced,and alveolar and interstitial edema was alleviated. The plasma level of TNF-?was significantly lower in PLA group compared with PE group,( P

Effects of Partical Liquid Ventilation on Gas Exchange, Hemodynamics, and Pulmonary Function in Newborn Piglet with Resipratory Distress

PURPOSE: To evaluate gas exchange, hemodynarnics and pulmonary function during partial liquid ventilation(PLV) using PFC(perfluorodecalin), compared with conventional gas ventilation in newborn piglets with saline lavage-induced respiratory distress. METHODS: In a total of 16 instrumented and ventilated piglets, acute respiratory distress(below 70 mmHg of PaOz at FiOz 1.0) was induced by repeated saline pulmonary lavage. The piglets were randomized to receive either gas ventilation only(control group, n=8) or PLV(PLV group, n=8) by 3 consecutive intratracheal instillations of 10mL/kg of perfluorodecalin at lavage baseline and at 30, 60min after lavage. All animals were mechanically ventilated for 150min after lavage with time-cycled pressure-limited gas ventilation, a peak inspiratory pressure of 30cm HO, frequency of 30breaths/min, FiO;, 1.0 and a positive end-expiratory pressure of 4cm HzO. All measurements were made at 30inin interval afterwards to 150rnin after lavage. RESULTS: All animals developed severe hypoxemia, hypercarbia, and acidosis due to increased transpulmonary shunt fraction after saline lavage, which persisted during the experiments in control group. PaOz significantly increased with increases in dosage of PFC from 56+/-6 to 235+/-90 mmHg and PaCOz also significantly decreased in the PLV group. Venous admixture and pH showed significant differences between the two groups. Pulmonary dynamic cornpliance, tidal volume and mean airway resistance were also significantly improved in the PLV group. However, hemodynamic parameters were similar in both groups. CONCLUSION: PLV with perfluorodecalin irnproves gas exchange and pulmonary function in newborn piglets with saline lavage-induced respiratory distress.

Effect of partial liquid ventilation with perfluorocarbon on the static lung compliance in rat with smoke inhalation injury / 中华麻醉学杂志

Objective: To evaluate the effect of partial liquid ventilation with perfluorocarbon on the static lung compliance in rat with smoke inhalation injury. Method: Partial liquid ventilation (PLV)and mechanical ventilation (MV)were set up on rat's model,total static lung compliance (C_(2.94))and low volume static lung compliance (C_(0.49))were measured with hydraulic pressometer,the expansion index(EI)of lung was calculated. Result: There were significant decrease in C_(2.94),C_(0.49) and EI after 6 hours of smoke inhalation injury as compared with control values (P0.05), but in partial liquid ventilation group C_(2.94).C_(0.49) and EI increased obviously compared with those in smoke inhalation injury and MV groups (P

Anti-inflammatory effect of partial liquid ventilation on acute lung injury / 中国病理生理杂志

AIM: To investigate the anti-inflammatory effect of partial liquid ventilation in the piglets with lung lavage-induced acute lung injury. METHODS: 16 piglets were treated by lung lavage to a partial pressure of oxygen in arterial blood (PaO_2) below 100 mmHg for one hour and randomly divided into mechanical ventilation group (MV group) and partial liquid ventilation group (PLV group). Blood-gas analysis, hemodynamics, the contents of TNF-?, MDA, SOD, and MPO activity in lung tissue were measured. RESULTS: (1) Lung W/D, PPI and the count of WBC in the BALF in PLV group were significantly lower than those in MV group. The contents of MDA and MPO in lung tissue in PLV group were significantly lower than those in MV group. However, no evident difference in SOD activity in lung tissue between two groups was observed. (2) The contents of TNF-? in lung tissue in PLV group were significantly lower than those in MV group. CONCLUSION: Partial liquid ventilation with perfluorocarbon has anti-inflammatory effect on lung lavage-induced acute lung injury in the piglets.

Effects of partial liquid ventilation on acute lung injury in piglets / 中国病理生理杂志

AIM: To observe the effect of partial liquid ventilation with perfluorocarbon on gas exchange, hemodynamics and lung histological change in the piglets with surfactant depletion-induced acute lung injury. METHODS: 12 piglets were treated by lung lavage to a partial pressure of oxygen in arterial blood (PaO 2) below 100 mmHg for one hour and randomly divided into gas ventilation group (control group) and partial liquid ventilation (PLV) group, in PLV group, piglets received PFC (FC3280) intratracheally at doses of 15 mL/kg. The parameters of gas exchange and hemodynamics were measured before lung lavage, after lung lavage when the acute lung injury (ALI) was established, and 1 hour, 2 hours after ALI. Animals underwent euthanasia at the end of the study, lung histologic analysis followed. RESULTS: Surfactant depletion by lung lavage induced a stable acute lung injury.Gas exchange increased markedly in the animals that underwent PLV, less hemodynamic damage was observed in PLV group compared with the animals in GV group. Lung histologic analysis demonstrated a less lung damage, including atelectasis, neutrophil excudation, intra-alveolar hemorrhage and interstitial edema in PLV group compared with control group. CONCLUSION: In piglets with surfactant depletion-induced acute lung injury, partial liquid ventilation with perfluorocarbon can improve the gas exchange with less adverse hemodynamic effect and less lung injury compared with conventional gas ventilation.

Effect of partial liquid ventilation with PFC on gas exchange and lung histopathology in piglets with acute lung injury / 中国病理生理杂志

AIM: To observe the effect of partial liquid ventilation on gas exchange and histopathological changes of lung in acute lung injury. METHODS: After acute lung injury (ALI) was induced by saline lavage,twenty piglets were assigned randomly to 2 groups: partial liquid ventilation with perfluorocarbon (PFC) group (PLV) and conventional gas ventilation group (CV). The changes of gas exchange were examined before ALI, during ALI and at 1,2,3,4 h after ALI, and histological sections taken from 8 different parts of lung were stained by H & E. RESULTS: The PaO_2 significantly increased and alveolar-aterial oxygen gradient (AaDO_2) markedly decreased in PLV group compare with CV group (P