ABSTRACT
PURPOSE: The present study was designed to examine effects of different mean airway pressure (MAP) settings during high-frequency oscillation (HFO) on oxygenation and inflammatory responses to acute lung injury (ALI) in rabbits. METHODS: Anesthetized rabbits were mechanically ventilated with a conventional mechanical ventilation (CMV) mode (tidal volume 6 ml/kg, inspired oxygen fraction [F(Io2)] of 1.0, respiratory rate [RR] of 30/min, positive end-expiratory pressure [PEEP] of 5 cmH(2)O). ALI was induced by intravenous administration of oleic acid (0.08 ml/kg) and the animals were randomly allocated to the following three experimental groups; animals (n = 6) ventilated using the same mode of CMV, or animals ventilated with standard MAP (MAP 10 cmH(2)O, n = 7), and high MAP (15 cmH(2)O, n = 6) settings of HFO (Hz 15). The MAP settings were calculated by the inflation limb of the pressure-volume curve during CMV. RESULTS: HFO with a high MAP setting significantly improved the deteriorated oxygenation during oleic acid-induced ALI and reduced wet/dry ratios, neutrophil counts and interleukin-8 concentration in bronchoalveolar lavage fluid, compared to those parameters in CMV and standard MAP-HFO. CONCLUSIONS: These findings suggest that only high MAP setting during HFO could contribute to decreased lung inflammation as well as improved oxygenation during the development of ALI.
ABSTRACT
High-frequency oscillatory ventilation (HFOV) is a possible mechanical method for open lung strategies. The aim of this study was to examine whether HFOV has a beneficial effect on oleic acid-induced lung injury, with emphasis on changes in extravascular lung water. Thirteen anesthetized sheep prepared with a lung lymph fistula and vascular catheters for monitoring were randomly allocated to two experimental groups. In experiment 1, sheep (n = 6) were ventilated using conventional mechanical ventilation [CMV; 10 ml/kg of tidal volume, 70% oxygen, and positive end-expiratory pressure (PEEP) of 6 cmH(2)O after oleic acid administration (0.08 ml/kg)]. In experiment 2, sheep (n=7) were ventilated using HFOV (frequency=15 Hz, stroke volume=120 ml, mean airway pressure=15 cmH(2)O) after administration of the same dose of oleic acid as in experiment 1. Observation was continued for 4 h after oleic acid administration, then bronchoalveolar lavage (BAL) was performed and the lung wet-to-dry weight ratio was determined. Compared with CMV, HFOV significantly improved the deteriorated oxygenation during the late phase (2-4 h) of oleic acid-induced lung injury without any deterioration effects on pulmonary or systemic hemodynamics. HFOV showed significantly reduced lung lymph protein clearance, which paralleled significant decreases in wet-to-dry ratios and neutrophil counts in BAL fluid in the HFOV group. These findings suggest that HFOV could contribute to decreased lung lymph filtration in pulmonary microcirculation and improved oxygenation following oleic acid-induced lung injury in sheep.
Subject(s)
High-Frequency Ventilation , Lung Injury/prevention & control , Lung/metabolism , Positive-Pressure Respiration , Animals , Blood Pressure , Bronchoalveolar Lavage Fluid/cytology , Carbon Dioxide/blood , Cardiac Output , Disease Models, Animal , Lung/physiopathology , Lung Injury/chemically induced , Lung Injury/metabolism , Lung Injury/physiopathology , Lymph/metabolism , Neutrophil Infiltration , Oleic Acid , Oxygen/blood , Proteins/metabolism , Pulmonary Circulation , Sheep , Time FactorsABSTRACT
BACKGROUND: This study was conducted to evaluate the effects of continuous epidural analgesia on the postoperative pain and the early recovery after laparoscopy-assisted gastrectomy (LAG). METHODS: A total of 66 patients undergoing elective LAG were investigated for postoperative pain score and other variables retrospectively. RESULTS: Forty-four patients who had received epidural analgesia (E group) showed significantly lower pain scores for 2, 12 and 48 hours after surgery, compared with 22 patients who had received analgesics intramuscularly or transrectally (C group). The patients in the E group needed significantly less supplemental analgesics than those in C group for 2 and 12 hours after the operation. The early recovery and the incidence of postoperative complications were not significantly different between the two groups. CONCLUSIONS: These results show that postoperative continuous epidural analgesia is effective for postoperative pain relief in patients after laparoscopy-assisted gastrectomy.
