- ICH GCP
- Registr klinických studií v USA
- Klinická studie NCT01569308
Pulse Pressure Variation Helps to Predict Fluid Responsiveness in Patients Ventilated With Low Tidal Volumes
Objective: To determine the value of pulse pressure variation (ΔRESPPP) to predict fluid responsiveness in patients ventilated with low tidal volumes (VT), and to investigate whether a lower ΔRESPPP cut-off point should be used when patients are ventilated with low tidal volumes.
Methods: This cross-sectional, observational study included 37 critically ill patients with acute circulatory failure requiring fluid challenge. They were sedated and mechanically ventilated with Tidal Volume (VT) 6-7 ml/kg IBW (ideal body weight), monitored by pulmonary artery catheter and arterial line. Mechanical ventilation and hemodynamic parameters, including ΔRESPPP, were measured before and after fluid challenge with 1,000 ml crystalloids or 500 ml colloids. Fluid responsiveness was defined as an increase of at least 15% in cardiac index.
The present study was designed to (1) determine the value of ΔRESPPP to predict fluid responsiveness in patients ventilated with low tidal volumes, and (2) to investigate whether a lower ΔRESPPP cut-off point should be used when patients are ventilated with low tidal volumes.
The study hypothesis is not a good predictor of fluid responsiveness in patients ventilated with low tidal volumes.
Přehled studie
Postavení
Podmínky
Detailní popis
Volume expansion is frequently used to treat critically ill patients with acute circulatory failure. The goal of volume expansion is to increase left ventricular stroke volume and consequently cardiac output. However, about 50% of patients with acute circulatory failure will respond to fluid challenge (preload- dependent patients). Therefore, the ability to predict fluid responsiveness in critically ill patients is crucial, particularly for ARDS patients because of increased alveolar-capillary membrane permeability, and avoiding unnecessary fluid loading has been shown to have a positive effect on patient outcome.Among the dynamic parameters used at the bedside to identify fluid responsiveness, pulse pressure variation (ΔRESPPP) is one of the most accurate in patients with acute circulatory failure receiving invasive mechanical ventilation. However, most studies evaluated patients ventilated with large tidal volumes (≥ 8 ml/kg). Therefore, the validity of ΔRESPPP to identify fluid responsiveness is still debated when lower tidal volumes are used.
The current literature about its performance during ventilation with low tidal volumes is unclear, and opposite conclusions have been drawn. The present study was designed to (1) determine the value of ΔRESPPP to predict fluid responsiveness in patients ventilated with low tidal volumes, and (2) to investigate whether a lower ΔRESPPP cut-off point should be used when patients are ventilated with low tidal volumes.
Methods: This cross-sectional, observational study included 37 critically ill patients with acute circulatory failure requiring fluid challenge. They were sedated and mechanically ventilated with Tidal Volume (VT) 6-7 ml/kg IBW (ideal body weight), monitored by pulmonary artery catheter and arterial line. Mechanical ventilation and hemodynamic parameters, including ΔRESPPP, were measured before and after fluid challenge with 1,000 ml crystalloids or 500 ml colloids. Fluid responsiveness was defined as an increase of at least 15% in cardiac index.
Patients were followed for 28 days or until discharge from the ICU.
Study Protocol Patients were sedated with midazolan and fentanyl (score of -4 to -5 in the Richmond Agitation Sedation Scale)and ventilated in controlled pressure or controlled volume mode (Servo I system v.12 or Servo 900 C, Siemens, Sweden) with VT < 8 ml/kg IBW (51 + 0.9[height in cm- 152.9] for men and 45.5 + 0.91[height in cm- 152.9] for women). Ventilatory and hemodynamic variables were measured before and after FC with the patients in a supine position. Zero pressure was measured at the midaxillary line. The correct position of the pulmonary artery catheter in West's zone 3 was checked as described in the literature.
Fluid challenge was performed with 1000 ml 0.9% saline solution or lactated Ringer's solution (n=36) or 500 ml hydroxy-ethyl-starch solution 6% 130/0.4 for 30 minutes (n=2).
Hemodynamic Parameters
Variations in arterial pulse pressure were visualized on bedside monitors (HP S66 and PHILIPS IntelliVue, MP60, Germany) and measured with the cursor for each of 5 breathing cycles. ΔRESPPP was calculated using the following equation:
ΔRESPPP (%) = 100 x (PPmax - PPmin) / [(PPmax + PPmin)/2]
where PPmax and PPmin are the maximal pulse pressure at inspiration and the pulse pressure obtained on expiration, respectively.
A pulmonary artery catheter (Edwards Healthcare, Irvine, CA) was used to measure cardiac output according to the thermal dilution method (3 injections of 10ml 0.9% saline solution), systolic, diastolic and mean pulmonary arterial pressures, pulmonary artery occlusion pressure (PAOP, mmHg), central venous pressure (CVP, mmHg), and mixed venous saturation (SvO2). Mean arterial pressure (MAP, mmHg), measured using the arterial line, and heart rate (HR, bpm) were also recorded. All measurements were made at the end of expiration, before and after FC. Patients were defined as fluid responders when cardiac index increased at least 15% of baseline value.
Ventilation Parameters The following ventilatory parameters were measured: inspiratory and expiratory tidal volume, respiratory rate (RR), plateau pressure (cmH2O), peak pressure (cmH2O), total positive end-expiratory pressure (PEEPtot), static compliance (Cst) and driving pressure (DP= Pplat-PEEP). All measurements were made before and after FC.
Statistical Analysis Sample size was defined as 38 patients for estimation of the correlation between CI and ΔRESPPP 0.5 (moderate to high magnitude), with a level of significance of 0.05 and power of 90%.
The effects of FC on hemodynamic parameters were assessed using a paired Student's t-test for normally distributed variables or a nonparametric Wilcoxon Signed Rank test for non-normally distributed variables. The comparison of hemodynamic parameters between both groups at baseline and after FC was assessed using a two sample Student's t-test or a nonparametric Mann-Whitney U test. Results were expressed as mean values±SD or median (25-75 percentiles).
Receiver operating characteristic (ROC) curves were constructed to evaluate the ability of ΔRESPPP, ΔRESPPP/DP, CVP and PAOP to predict fluid responsiveness. The best cut-off value for ΔRESPPP ROC curve was determined for the entire population. In addition, measures of diagnostic performance were calculated: sensitivity, specificity, predictive values and likelihood ratio. Linear correlations were tested using the Spearman rank method. Data were analyzed using SPSS 15.0. A p value <0.05 was considered significant.
Typ studie
Zápis (Aktuální)
Kontakty a umístění
Studijní místa
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Rio Grande do Sul
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Porto Alegre, Rio Grande do Sul, Brazílie, 90035903
- Hospital de Clínicas de Porto Alegre
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Kritéria účasti
Kritéria způsobilosti
Věk způsobilý ke studiu
Přijímá zdravé dobrovolníky
Pohlaví způsobilá ke studiu
Metoda odběru vzorků
Studijní populace
Popis
Inclusion Criteria:
- Age ≥ 16 years
- Hemodynamic instability defined as need for norepinephrine infusion and/or intravascular fluid administration to maintain systolic arterial blood pressure > 90 mm Hg
- Arterial line in place (radial or femoral)
- Pulmonary arterial catheter in place
Exclusion Criteria:
- Presence of cardiac arrhythmias
- Presence of pneumothorax
- Presence of heart valve disease or intracardiac shunt
- Previously diagnosed right ventricular insufficiency
Studijní plán
Jak je studie koncipována?
Detaily designu
- Observační modely: Kohorta
- Časové perspektivy: Průřezový
Co je měření studie?
Primární výstupní opatření
Měření výsledku |
Popis opatření |
Časové okno |
---|---|---|
Increase in cardiac index at least 15% of baseline value.
Časové okno: Cardiac index was measured at the end of a 30 minutes fluid challenge.
|
Patients were sedated and ventilated in controlled pressure or controlled volume mode (Servo I system v.12 or Servo 900 C, Siemens, Sweden) with VT < 8 ml/kg ideal body weight.
Ventilatory and hemodynamic variables were measured before and after FC with the patients in a supine position.
Fluid challenge was performed with 1000 ml 0.9% saline solution or lactated Ringer's solution or 500 ml hydroxy-ethyl-starch solution 6% 130/0.4 for 30 minutes.
The increase in cardiac index was measured immediately after fluid challenge.
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Cardiac index was measured at the end of a 30 minutes fluid challenge.
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Sekundární výstupní opatření
Měření výsledku |
Popis opatření |
Časové okno |
---|---|---|
Mortality
Časové okno: 28 days
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Patients were followed for 28 days or until ICU discharge
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28 days
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Spolupracovníci a vyšetřovatelé
Vyšetřovatelé
- Vrchní vyšetřovatel: Gilberto Friedman, Hospital de Clínicas de Porto Alegre
Publikace a užitečné odkazy
Termíny studijních záznamů
Hlavní termíny studia
Začátek studia
Primární dokončení (Aktuální)
Dokončení studie (Aktuální)
Termíny zápisu do studia
První předloženo
První předloženo, které splnilo kritéria kontroly kvality
První zveřejněno (Odhad)
Aktualizace studijních záznamů
Poslední zveřejněná aktualizace (Odhad)
Odeslaná poslední aktualizace, která splnila kritéria kontroly kvality
Naposledy ověřeno
Více informací
Termíny související s touto studií
Další identifikační čísla studie
- 06-109
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