ABSTRACT
Objective To evaluate the effect of airway pressure release ventilation (APRV) in patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS), to evaluate the extent of ventilator-induced lung injury (VILI), and to explore its possible mechanism. Methods A prospective study was conducted in the Department of Critical Care Medicine of the First Hospital of Hebei Medical University from December 2010 to February 2012. The patients with ALI/ARDS were enrolled. They were randomly divided into two groups. The patients in APRV group were given APRV pattern, while those in control group were given lung protection ventilation, synchronized intermittent mandatory ventilation with positive end-expiratory pressure (SIMV+PEEP). All patients were treated with AVEA ventilator. The parameters such as airway peak pressure (Ppeak), mean airway pressure (Pmean), pulse oxygen saturation (SpO2), mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), arterial blood gas, urine output (UO), the usage of sedation and muscle relaxation drugs were recorded. AVEA ventilator turning point (Pflex) operation was used to describe the quasi-static pressure volume curve (P-V curve). High and low inflection point (UIP, LIP) and triangular Pflex volume (Vdelta) were automatically measured and calculated. The ventilation parameters were set, and the 24-hour P-V curve was recorded again in order to be compared with subsequent results. Venous blood was collected before treatment, 24 hours and 48 hours after ventilation to measure lung surfactant protein D (SP-D) and large molecular mucus in saliva (KL-6) by enzyme linked immunosorbent assay (ELISA), and the correlation between the above two parameters and prognosis on 28 days was analyzed by multinomial logistic regression. Results Twenty-six patients with ALI/ARDS were enrolled, and 22 of them completed the test with 10 in APRV group and 12 in control group. The basic parameters and P-V curves between two groups were similar before the test. After 24 hours and 48 hours, mechanical ventilation was given in both groups. The patients' oxygenation was improved significantly, though there were no significant changes in hemodynamic parameters. The Pmean (cmH2O, 1 cmH2O = 0.098 kPa) in APRV group was significantly higher than that in control group (24 hours: 24.20±4.59 vs. 17.50±3.48, P 0.05). The SP-D level (μg/L) in serum in APRV group showed a tendency of increase (increased from 19.70±7.34 to 27.61±10.21, P 0.05), the difference between the two groups was statistically significant (P 0.05). There was no significant difference in serum KL-6 between the two groups before and after ventilation. The SP-D and KL-6 levels in serum were unrelated with 28-day survival rate of the patients. The odds ratio (OR) of SP-D were 0.900 [95% confidence interval (95%CI) = 0.719-1.125], 1.054 (95%CI = 0.878-1.266), 1.143 (95%CI = 0.957-1.365), and the OR of KL-6 were 1.356 (95%CI = 0.668-2.754), 0.658 (95%CI = 0.161-2.685), 0.915 (95%CI = 0.350-2.394) before the test, 24 hours and 48 hours after ventilation (all P > 0.05). Conclusions APRV was similar to lung protective ventilation strategy in oxygenation and improvements in the lung mechanics parameters. APRV with a higher Pmean can recruit alveolar more effectively, and it had no impact on hemo-dynamics, but might exacerbate VILI.
ABSTRACT
Objective To investigate the effects of airway pressure release ventilation (APRV) in children with severe pneumonia-related acute respiratory distress syndrome(ARDS).Methods Ten children suffering severe pneumonia-related ARDS with APRV were included in Pediatric Intensive Care Unit, Beijing Children's Hospital,Capital Medical University from March 2011 to October 2014.Ventilation variables, changes of airway pressure and Ramsay scores were collected and compared with that in conventional ventilation (CV).Clinical variables were measured at CV before APRV and at 1,4,12,24 hours after transition to APRV.Results High airway pressure(Phigh) at each time point during APRV was significantly lower than peak airway pressure (Ppeak) or plateau airway pressure (Pplat) in CV[(26.00 ±2.94) cmH2O(1 cmH2O =0.098 kPa) ,(24.40 ±3.34) cmH2O,(23.30 ±3.46) cmH2O,(23.00 ± 3.80) cmH2O vs (31.80 ± 5.59) cmH2O, P ＜ 0.01].Mean airway pressure (Pmean) at each time point during APRV was significantly higher than that in CV [(23.00 ± 2.86) cmH2 O, (21.69 ± 3.12) cmH2 O, (20.89 ± 3.31) cmH2 O, (20.46 ± 3.48) cmH2 O vs (17.50 ± 2.37) cmH2 O, P ＜ 0.05].Fraction of inspired oxygen (FiO2) were significantly decreased at 4, 12 and 24 hours after APRV than that in CV [(73.00 ± 22.39) ％, (63.50 ± 20.16) ％, (63.00 ± 21.11) ％ vs (88.00 ± 15.49) ％, P ＜ 0.05].Ramsay scores were significantly decreased at each time point during after APRV than that in CV [(3.90 ± 0.74) scores, (2.90 ± 0.88) scores, (3.00 ± 1.15) scores,(3.50 ± 0.71) scores vs (4.60 ± 0.52) scores, P ＜ 0.05].Conclusions Compared with CV, APRV had a lower Phigh and FiO2 ,a higher Pmean and more shallow sedation.APRV may be an effective ventilation mode in children's severe pneumonia-related ARDS.
ABSTRACT
La ventilación con liberación de presión en la vía aérea (APRV) es una modalidad ventilatoria que utiliza presión positiva controlada en la vía aérea, con el fin de maximizar el reclutamiento alveolar, con tiempos inspiratorios prolongados, permitiendo la respiración espontánea durante ambas fases del ciclo respiratorio. Los autores describen su experiencia en una serie de 12 casos con pacientes neonatales con insuficiencia respiratoria aguda, que fueron tratados con la APRV ventilación con liberación de presión en la vía aérea, cuando la oxigenación no mejoró con la ventilación de control de presión. La edad media de los pacientes fue de 13+16,5 días. La fracción inspirada de oxígeno disminuyó de 62,9 +23,6+ cm H2O para la ventilación de control de presión a 44+14,0 cm H2O para la APRV. El promedio de presión de oxígeno aumentó de 54,6+11,9mmHg a 92+32mmH; el promedio de presión parcial de CO2 disminuyó de 53,2+15,6 mmHg a 43,1+10mmHg, y la presión pico de la vía aérea se redujo de 16,8+5,9 cm H2O a 16,6+5,3 cm de H2O, respectivamente. La ventilación con liberación de presión en la vía aérea, puede mejorar la oxigenación en pacientes pediátricos con insuficiencia respiratoria aguda, cuando la ventilación mecánica convencional falla...
Subject(s)
Humans , Infant, Newborn , Infant , Respiratory Insufficiency , Intermittent Positive-Pressure Ventilation , VentilationABSTRACT
Airway pressure release ventilation (APRV) is a relatively new mode of mechanical ventilation. The use of this model of ventilation in pediatrics has been limited. The authors describe their experience with this mode of ventilation in a series of pediatric hypoxemic respiratory failure patients. Three patients with acute hypoxemic respiratory failure (AHRF) were treated with APRV, when oxygenation did not improve with pressure control ventilation (PCV). The mean age of the patients was 5.8± 1.3 months. Fractional oxygen concentration decreased from 0.97±0.02 for PCV to 0.68±0.12 for APRV, peak airway pressure fell from 36.6±11.5 cm H2O for PCV to 33.3±5.7 cm H2O for APRV, mean airway pressure increased from 17.9±5.9 cmH2O for PCV to 27± 2.6 cmH2O for APRV and release tidal volume increased from 8.3±1.5 mL/kg for PCV to 13.2±1.1 mL/kg for APRV after 1 h. APRV may improve oxygenation in pediatric AHRF when conventional mechanical ventilation fails. The APRV modality may provide better oxygenation with lower peak airway pressure.
ABSTRACT
Objective To compare the effect of pressure regulated biphasic positive airway pressure ventilation(BiPAP) and airway pressure release ventilation(APRV) on cardiopulmonary function of pigs with or without acute lung injury. Methods after anaesthesia, 18 healthy pigs were given BiPAP or APRV ventilation through tracheotomy. Inspiration pressure and expiration pressure in BiPAP equal to APRV. Inspiration time and expiration time is 1.5/2.5s in BiPAP and 4.0/2.0s, 4.5/1.5s, 5.0/1.0s, 5.5/0.5s in APRV respectively. Respiration dynamics, hemodynamics, blood gases and oxygen metabolize scales were measured during two mechanical ventilatory modalities pigs acquired from Swam-gans catheter in internal jugular vein and from catheter in femoral artery. Then oleic-induced acute lung injury model was made, modalities pigs were distributed to BiPAP group (n=9) and APRV group (n=8) randomly. Forenamed scales were repeat measured. Results BiPAP has not difference with APRV on respiration dynamics, hemodynamics, blood gases and oxygen metabolize during normal condition, BiPAP has higher cardiac output (CO) and lower oxygen extraction ratio (O2ER) compare with APRV in ALI pigs. If expiration time is short to 0.5s in APRV, it would represent intrinsic peak end-expiratory (PEEPi), heart rate (HR), mean pulmonary arterial pressure (MPAP) and systemic vascular resistance (SVR) increased and CO decreased. Conclusion Both BiPAP and APRV are beneficial in ALI, but BiPAP has fewer side-effect compared with APRV in early ALI.