Bendel-Stenzel E M, Mrozek J D, Bing D R, Meyers P A, Connett J E, Mammel M C
Infant Pulmonary Research Center, Children's Hospitals and Clinics, St. Paul, Minnesota, USA.
Pediatr Pulmonol. 1998 Nov;26(5):319-25. doi: 10.1002/(sici)1099-0496(199811)26:5<319::aid-ppul3>3.0.co;2-v.
This study evaluates different ventilator strategies during gas (GV) and partial liquid ventilation (PLV) in spontaneously breathing animals. We hypothesized that during PLV, spontaneously breathing animals would self-regulate respiratory parameters by increasing respiratory rate (RR) and minute ventilation (V'E) when compared to animals mechanically ventilated with gas, and further that full synchronization of each animal's effort to the ventilator cycle would decrease RR at stable tidal volumes (V(T)). We studied 12 newborn piglets (1.54 +/- 0.24 kg) undergoing GV and PLV in 3 different modes: intermittent mandatory ventilation (IMV), synchronized IMV (SIMV), and assist control ventilation (AC). Modes occurred sequentially in random order during GV first, with the same order then repeated during PLV. Animals initially received continuous positive airway pressure (CPAP) and returned to CPAP during PLV at the end of the experiment. Pressure-limited, volume-targeted ventilation was used with a tidal volume goal of 13 cc/kg. Rate was set at 10/min during IMV and SIMV, with a back-up rate of 10/min during AC. RR, V'E, mechanical (V(T)) and spontaneous tidal volumes (sV(T)) were measured breath-to-breath using a computer-assisted lung mechanics analyzer; mean values were determined over 30-min periods. Data analysis used paired t-tests with Bonferroni correction as needed (P < 0.05). Blood gases were stable in all modes during GV and PLV. RR (min(-1)) and V'E (L x min(-1)/kg) increased in all modes from GV to PLV (RR: CPAP 71 vs. 128; IMV 69 vs. 112; SIMV 65 vs. 107; AC 33 vs. 47. V'E: CPAP 0.47 vs. 0.72; IMV 0.46 vs. 0.61; SIMV 0.45 vs. 0.61; AC 0.38 vs. 0.53; P < 0.05). Intermode comparisons during PLV showed a lower RR with AC (P < 0.02), and a higher V'E with CPAP (P < 0.05). V(T) and dynamic respiratory system compliance decreased from GV to PLV (V(T) P < 0.05; C(rs,dyn) P < 0.01); sV(T) remained unchanged. V(T) and sV(T) did not differ in intermode comparisons. We conclude that during PLV, spontaneously breathing piglets with normal lungs maintain physiologic blood gases by increasing V'E through increased RR. AC produced the most efficient respiratory pattern during PLV, with increased V'E achieved by a modest increase in RR.
本研究评估了在自主呼吸动物中进行气体通气（GV）和部分液体通气（PLV）时的不同通气策略。我们假设，与接受气体机械通气的动物相比，在PLV期间，自主呼吸动物会通过增加呼吸频率（RR）和分钟通气量（V'E）来自我调节呼吸参数，并且进一步假设，在潮气量（V(T)）稳定时，每只动物的呼吸努力与通气机周期完全同步会降低RR。我们研究了12只新生仔猪（体重1.54±0.24千克），它们在3种不同模式下接受GV和PLV：间歇强制通气（IMV）、同步IMV（SIMV）和辅助控制通气（AC）。这些模式在GV期间首先以随机顺序依次出现，然后在PLV期间重复相同顺序。动物最初接受持续气道正压通气（CPAP），并在实验结束时的PLV期间恢复到CPAP。采用压力限制、容量目标通气，潮气量目标为13毫升/千克。IMV和SIMV期间的速率设定为10次/分钟，AC期间的备用速率为10次/分钟。使用计算机辅助肺力学分析仪逐次测量RR、V'E、机械通气潮气量（V(T)）和自主潮气量（sV(T)）；在30分钟时间段内确定平均值。数据分析在需要时使用配对t检验并进行Bonferroni校正（P<0.05）。在GV和PLV期间，所有模式下的血气均稳定。从GV到PLV，所有模式下的RR（次/分钟）和V'E（升×分钟-1/千克）均增加（RR：CPAP 71对128；IMV 69对112；SIMV 65对107；AC 3 vs. 47。V'E：CPAP 0.47对0.72；IMV 0.46对0.61；SIMV 0.45对0.61；AC 0.38对0.53；P<0.05）。PLV期间的模式间比较显示，AC的RR较低（P<0.02），CPAP的V'E较高（P<0.05）。从GV到PLV，V(T)和动态呼吸系统顺应性降低（V(T) P<0.05；C(rs,dyn) P<0.01）；sV(T)保持不变。模式间比较中，V(T)和sV(T)没有差异。我们得出结论，在PLV期间，肺部正常的自主呼吸仔猪通过增加RR来增加V'E，从而维持生理血气。AC在PLV期间产生了最有效的呼吸模式，通过RR适度增加实现了V'E增加。
