Limits...
Pulse pressure variation shows a direct linear correlation with tidal volume in anesthetized healthy patients

View Article: PubMed Central - PubMed

ABSTRACT

Background: The settings of mechanical ventilation, like tidal volume (VT), occasionally need to be adjusted in the process of anesthesia for some special reasons. The aim of this study was therefore to assess the relationship between pulse pressure variations (PPVs) in different settings of VT in anesthetized healthy patients under mechanical ventilation.

Methods: Sixty nine ASA I-II patients scheduled for gastrointestinal surgery under general anesthesia were included in this prospective study. All the patients were ventilated at a VT of 6, 8 or 10 ml/kg (predicted body weight) with no positive end expiratory pressure (PEEP) in a random order after intubation. PPV, mean arterial blood pressure, and other hemodynamic and respiratory parameters were recorded in each VT setting respectively after Partial Pressure of End-Tidal Expiration Carbon Dioxide (PetCO2) maintained between 30 mmHg and 40 mmHg by changing Respiratory Rate (RR) before incision.

Results: The values of PPV at different settings of VT showed a tight correlation between each other (6 vs. 8 ml/kg: r = 0.97, P < 0.0001; 6 vs.10 ml/kg: r = 0.95, P < 0.0001; 8 vs. 10 ml/kg: r = 0.98, P < 0.0001, respectively).

Conclusion: There is a direct linear correlation between PPVs at different tidal volumes in anesthetized ASA I-II patients. PPV in any of the 3 VT settings (6, 8 or 10 ml/kg) can deduce that in any other 2 settings. Further studies are needed to explore the effect of intraoperative confounders for this knowledge to be clinically applied.

Trial registration: NCT01950949, www.clinicaltrials.gov, July 26, 2013.

No MeSH data available.


Linear relationship between PPVs under the VT of 6, 8 and 10 ml/kg after volume expansion. PPV6: pulse pressure variation at a VT of 6 ml/kg; PPV8: pulse pressure variation at a VT of 8 ml/kg; PPV10: pulse pressure variation at a VT of 10 ml/kg. Equation (a) represented the linear correlation between PPV6 and PPV 8. Equation (b) represented the linear correlation between PPV6 and PPV 10. Equation (c) represented the linear correlation between PPV8 and PPV10.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC5017055&req=5

Fig4: Linear relationship between PPVs under the VT of 6, 8 and 10 ml/kg after volume expansion. PPV6: pulse pressure variation at a VT of 6 ml/kg; PPV8: pulse pressure variation at a VT of 8 ml/kg; PPV10: pulse pressure variation at a VT of 10 ml/kg. Equation (a) represented the linear correlation between PPV6 and PPV 8. Equation (b) represented the linear correlation between PPV6 and PPV 10. Equation (c) represented the linear correlation between PPV8 and PPV10.

Mentions: A significant linear correlation between PPVs at a VT of 6 ml/kg and 8 ml/kg was found in the study(r = 0.97), and the linear regression equation was Y =1.1691 + 1.2277X. There was also a significant linear correlation between PPVs at a VT of 6 ml/kg and 10 ml/kg (r = 0.94), and the linear regression equation was Y = 1.5888 + 1.5549X. Moreover, a significant linear correlation was observed between PPVs at a VT of 8 ml/kg and 10 ml/kg (r = 0.98; linear regression equation, Y = -0.044 + 1.2795X) (Fig. 3). The patients in the subgroup (27 patients who received volume expansion) showed a significant linear correlation between the PPV values under the three VT settings (PPV6 vs. PPV8: r = 0.96; PPV6 vs. PPV10: r = 0.92; PPV8 vs. PPV10: r = 0.98). The correlation coefficient of the subgroup was similar with the initial observations (Fig. 4).Fig. 3


Pulse pressure variation shows a direct linear correlation with tidal volume in anesthetized healthy patients
Linear relationship between PPVs under the VT of 6, 8 and 10 ml/kg after volume expansion. PPV6: pulse pressure variation at a VT of 6 ml/kg; PPV8: pulse pressure variation at a VT of 8 ml/kg; PPV10: pulse pressure variation at a VT of 10 ml/kg. Equation (a) represented the linear correlation between PPV6 and PPV 8. Equation (b) represented the linear correlation between PPV6 and PPV 10. Equation (c) represented the linear correlation between PPV8 and PPV10.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5017055&req=5

Fig4: Linear relationship between PPVs under the VT of 6, 8 and 10 ml/kg after volume expansion. PPV6: pulse pressure variation at a VT of 6 ml/kg; PPV8: pulse pressure variation at a VT of 8 ml/kg; PPV10: pulse pressure variation at a VT of 10 ml/kg. Equation (a) represented the linear correlation between PPV6 and PPV 8. Equation (b) represented the linear correlation between PPV6 and PPV 10. Equation (c) represented the linear correlation between PPV8 and PPV10.
Mentions: A significant linear correlation between PPVs at a VT of 6 ml/kg and 8 ml/kg was found in the study(r = 0.97), and the linear regression equation was Y =1.1691 + 1.2277X. There was also a significant linear correlation between PPVs at a VT of 6 ml/kg and 10 ml/kg (r = 0.94), and the linear regression equation was Y = 1.5888 + 1.5549X. Moreover, a significant linear correlation was observed between PPVs at a VT of 8 ml/kg and 10 ml/kg (r = 0.98; linear regression equation, Y = -0.044 + 1.2795X) (Fig. 3). The patients in the subgroup (27 patients who received volume expansion) showed a significant linear correlation between the PPV values under the three VT settings (PPV6 vs. PPV8: r = 0.96; PPV6 vs. PPV10: r = 0.92; PPV8 vs. PPV10: r = 0.98). The correlation coefficient of the subgroup was similar with the initial observations (Fig. 4).Fig. 3

View Article: PubMed Central - PubMed

ABSTRACT

Background: The settings of mechanical ventilation, like tidal volume (VT), occasionally need to be adjusted in the process of anesthesia for some special reasons. The aim of this study was therefore to assess the relationship between pulse pressure variations (PPVs) in different settings of VT in anesthetized healthy patients under mechanical ventilation.

Methods: Sixty nine ASA I-II patients scheduled for gastrointestinal surgery under general anesthesia were included in this prospective study. All the patients were ventilated at a VT of 6, 8 or 10 ml/kg (predicted body weight) with no positive end expiratory pressure (PEEP) in a random order after intubation. PPV, mean arterial blood pressure, and other hemodynamic and respiratory parameters were recorded in each VT setting respectively after Partial Pressure of End-Tidal Expiration Carbon Dioxide (PetCO2) maintained between 30 mmHg and 40 mmHg by changing Respiratory Rate (RR) before incision.

Results: The values of PPV at different settings of VT showed a tight correlation between each other (6 vs. 8 ml/kg: r = 0.97, P < 0.0001; 6 vs.10 ml/kg: r = 0.95, P < 0.0001; 8 vs. 10 ml/kg: r = 0.98, P < 0.0001, respectively).

Conclusion: There is a direct linear correlation between PPVs at different tidal volumes in anesthetized ASA I-II patients. PPV in any of the 3 VT settings (6, 8 or 10 ml/kg) can deduce that in any other 2 settings. Further studies are needed to explore the effect of intraoperative confounders for this knowledge to be clinically applied.

Trial registration: NCT01950949, www.clinicaltrials.gov, July 26, 2013.

No MeSH data available.