The effects of Pressure Control versus Volume Control Assisted Ventilation on Patient work of Breathing in Acute Lung Injury and Acute Respiratory Distress Syndrome
Restricted accessResearch articleFirst published online September, 2000
The effects of Pressure Control versus Volume Control Assisted Ventilation on Patient work of Breathing in Acute Lung Injury and Acute Respiratory Distress Syndrome
BACKGROUND: Patient work of breathing (WOB) during assisted ventilation is reduced when inspiratory flow (V₁) from the ventilator exceeds patient flow demand. Patients in acute respiratory failure often have unstable breathing patterns and their requirements for V₁ may change from breath to breath. Volume control ventilation (VCV) traditionally incorporates a pre-set ventilator V₁ that remains constant even under conditions of changing patient flow demand. In contrast, pressure control ventilation (PCV) incorporates a variable decelerating flow wave form with a high ventilator V₁ as inspiration commences. We compared the effects of flow patterns on assisted WOB during VCV and PCV. METHODS: WOB was measured with a BICORE CP-100 monitor (incorporating a Campbell Diagram) in a prospective, randomized cross-over study of 18 mechanically ventilated adult patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Tidal volume, inspiratory time, and mean ventilator V₁ were constant in each mode. RESULTS: At comparable levels of respiratory drive and minute ventilation, patient WOB was significantly lower with PCV than with VCV (0.59 ± 0.42 J/L vs 0.70 ± 0.58 J/L, respectively, p < 0.05). Ventilator peak V₁ was significantly higher with PCV than with VCV (103.2 ± 22.8 L/min vs 43.8 L/min, respectively, p < 0.01). CONCLUSIONS: In the setting of ALI and ARDS, PCV significantly reduced patient WOB relative to VCV. The decrease in patient WOB was attributed to the higher ventilator peak V₁ of PCV.
MariniJJ, CappsJS, CulverBH. The inspiratory work of breathing during assisted mechanical ventilation. Chest1985;87:612–618.
2.
MariniJJ, RodriguezM, LambV.The inspiratory workload of patient-initiated mechanical ventilation. Am Rev Respir Dis1986;134:902–909.
3.
WardME, CorbeilC, GibbonsW, NewmanS, MacklemPT. Optimization of respiratory muscle relaxation during mechanical ventilation. Anesthesiology1988;69:29–35.
4.
SassoonCSH, MahutteCK, TeTT, SimmonsDH, LightRW. Work of breathing and airway occlusion pressure during assist-mode mechanical ventilation. Chest1988;93:571–576.
5.
DerenneJPH, MacklemPT, RoussosCH. The respiratory muscles: mechanics, control and pathophysiology. Am Rev Respir Dis1978;118:119–133.
6.
SilvermanL, LeeG, PlotkinT, SawyersLA, YanceyAR. Air flow measurements on human subjects with and without respiratory resistance at several work rates. Arch Ind Hyg Occup Med1951;3:461–478.
7.
BernasconiM, PloysongsangY, GottfriedSB, Milic-EmiliJ, RossiA.Respiratory compliance and resistance in mechanically ventilated patients with acute respiratory failure. Intensive Care Med1988;14:547–553.
8.
KatzJA, ZinnSE, OzanneGM, FairleyHB. Pulmonary, chest wall, and lung-thorax elastances in acute respiratory failure. Chest1981;80:304–311.
9.
MariniJJ. The role of the inspiratory circuit in the work of breathing during mechanical ventilation. Respir Care1987;32:419–427; discussion 427–430.
10.
KalletR.The effects of flow patterns on pulmonary gas exchange, lung-thorax mechanics, and circulation. Respir Care1996;41:611–624.
11.
BernardGR, ArtigasA, BrighamKL, CarletJ, FalkeK, HudsonL, et al. The American-European Consensus Conference on ARDS: Definitions, mechanisms, relevant outcomes and clinical trial coordination. Am J Respir Crit Care Med1994;149:818–824.
12.
BaydurA, BehrakisPK, ZinWA, JaegerM, Milic-EmiliJ.A simple method for assessing the validity of the esophageal balloon technique. Am Rev Respir Dis1982;126(5):788–791.
13.
MariniJJ, SmithTC, LambV.Estimation of inspiratory muscle strength in mechanically ventilated patients: The measurement of Pimax. J Crit Care1986;1:32–38.
14.
Van de GraaffWB, GordeyK, DornseifSE, DriesDJ, KleinmanBS, KumarP, MathruM.Pressure support: changes in ventilatory pattern and components of the work of breathing. Chest1991;100:1082–1089.
15.
BlanchPB, BannerMJ. A new respiratory monitor that enables accurate measurements of work of breathing: a validation study. Respir Care1994;39:897–905.
16.
PetrosAJ, LamondCT, BennettD.The Bicore pulmonary monitor: a device to access the work of breathing while weaning from mechanical ventilation. Anaesthesia1993;48:985–988.
17.
SassoonCSH, LightRW, LodiaR, SieckGC, MahutteCK. Pressure-time product during continuous positive airway pressure, pressure support ventilation, and T-piece during weaning from mechanical ventilation. Am Rev Respir Dis1991;143:469–475.
18.
PelosiP, CeredaM, FotiG, GiacominiM, PesentiA.Alterations of lung and chest wall mechanics in patients with acute lung injury: effects of positive end-expiratory pressure. Am J Respir Crit Care Med1995;152:531–537.
19.
MurrayJF, MatthayMA, LuceJM, FlickMR. An expanded definition of the adult respiratory distress syndrome. Am Rev Respir Dis1988;138:720–723.
20.
AlbertiA, GalloF, FongaroA, ValentiS, RossiA.Po. 1 is a useful parameter in setting the level of pressure support ventilation. Intensive Care Med1995;21:547–553.
21.
HubmayrRD. Setting the ventilator. In: TobinMJ, editor. Principles and practice of mechanical ventilation. New York: McGraw-Hill; 1994: 191–206.
22.
MariniJJ. Monitoring during mechanical ventilation. Clin Chest Med1988;9:73–100.
23.
MorganrothML, MorganrothJL, NettLM, PettyTL. Criteria for weaning from prolonged mechanical ventilation. Arch Intern Med1984;144:1012–1016.
24.
LemaireF.Difficult weaning. Intensive Care Med1993;19:S69–S73.
25.
SahnSA, LakshminarayanS.Bedside criteria for discontinuation of mechanical ventilation. Chest1973;63:1002–1005.
26.
YangKL, TobinMJ. A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation. N Engl J Med1991;324:1445–1450.
27.
RoussosC, MacklemPT. Diaphragmatic fatigue in man. J Appl Physiol1977;43:189–197.
28.
LevyMM, MiyasakiA, LangstonD.Work of breathing as a weaning parameter in mechanically ventilated patients. Chest1995;108:1018–1020.
29.
HenningRJ, ShubinH, WeilMH. The measurement of the work of breathing for clinical assessment of ventilator dependence. Crit Care Med1977;5:264–268.
30.
BellemereF, GrassinoA.Effect of pressure and timing of contraction on human diaphragm fatigue. J Appl Physiol1982;53:1190–1195.
31.
PetrofBJ, LegareM, GoldbergP, Milic-EmiliJ, GottfriedSB. Continuous positive airway pressure reduces work of breathing and dyspnea during weaning from mechanical ventilation in severe chronic obstructive pulmonary disease. Am Rev Respir Dis1990;141:281–289.
32.
CollettPW, PerryC, EngelLA. Pressure-time product, flow and oxygen cost of resisitve breathing in humans. J Appl Physiol1985;58:1263–1272.
33.
CampbellEJM. The respiratory muscles and the mechanics of breathing. Chicago: Year Book Publishers; 1958: 83–87.
34.
BannerMJ, KirbyRR, GabrielliA, BlanchPB, LayonAJ. Partially and totally unloading respiratory muscles based on real-time measurements of work of breathing: a clinical approach. Chest1994;106:1835–1842.
35.
CinnellaG, ContiG, LofasoF, LorinoH, HarfA, LemaireF, BrochardL.Effects of assisted ventilation on the work of breathing: volume-controlled versus pressure-controlled ventilation. Am J Respir Crit Care Med1996;153:1025–1033.
36.
BlanchPB, JonesM, LayonAJ, CamnerN.Pressure-present ventilation. Part 1: Physiologic and mechanical considerations. Chest1993;104:590–599.
37.
HaasCF, BransonRD, FolkLM, CampbellRS, WiseCR, DavisK, et al. Patient-determined inspiratory flow during assisted mechanical ventilation. Respir Care1995;40:716–721.
38.
MacIntyreNR, McConnellR, ChengKCG, SaneA.Patient-ventilator flow dyssynchrony: flow-limited versus pressure-limited breaths. Crit Care Med1997;25:1671–1677.
39.
FernandezR, MendezM, YounesM.Effect of ventilator flow rate in the volume-cycled mode on neural inspiratory duration (TIN) in normal subjects (abstract). Am J Respir Crit Care Med1997;155:A83.
40.
PuddyA, YounesM.Effect of inspiratory flow rate on respiratory output in normal subjects. Am Rev Respir Dis1992;146:787–789.
41.
HawryluckL, GeorgopoulosD, BshoutyZ.Interaction between peak inspiratory flow and mechanical inspiratory time (TIM) and their effect on respiratory output (abstract). Am J Respir Crit Care Med1997;155:A363.
42.
LeeversAM. The effects of varying inspiratory flow rate during assisted ventilation on respiratory output (abstract). Am J Respir Crit Care Med1997;155:A365.
43.
BshoutyZ, GeorgopoulosD.The effect of mean versus peak inspiratory flow on respiratory output (abstract). Am J Respir Crit Care Med1997;155:A365.
