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Evaluation of adjusted central venous blood gases versus arterial blood gases of patients in post-operative paediatric cardiac surgical intensive care unit.

Singh NG, Prasad SR, Manjunath V, Nagaraja PS, Adoni PJ, Gopal D, Jagadeesh AM - Indian J Anaesth (2015)

Bottom Line: Central venous catheters are in situ in most of the intensive care unit (ICU) patients, which may be an alternative for determining acid-base status and can reduce complications from prolonged arterial cannulation.ABG and aVBG samples showed strong correlation, acceptable mean differences and improved agreement (high ICC) after adjusting the VBG.Hence, it can be promising to use trend values of VBG instead of ABG in conjunction with a correction factor under stable haemodynamic conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiac Anaesthesiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka, India.

ABSTRACT

Background and aims: Central venous catheters are in situ in most of the intensive care unit (ICU) patients, which may be an alternative for determining acid-base status and can reduce complications from prolonged arterial cannulation. The aim of this study was to examine the reliability between adjusted central venous blood gas (aVBG) and arterial blood gas (ABG) samples for pH, partial pressure of carbon-di-oxide (pCO2), bicarbonate (HCO3 (-)), base excess (BE) and lactates in paediatric cardiac surgical ICU.

Methods: We applied blood gas adjustment rule, that is aVBG pH = venous blood gas (VBG) pH +0.05, aVBG CO2 = VBG pCO2 - 5 mm Hg from the prior studies. In this study, we validated this relationship with simultaneous arterial and central venous blood obtained from 30 patients with four blood sample pairs each in paediatric cardiac surgical ICU patients.

Results: There was a strong correlation (R i.e., Pearson's correlation) between ABG and aVBG for pH = 0.9544, pCO2 = 0.8738, lactate = 0.9741, HCO3 (-) = 0.9650 and BE = 0.9778. Intraclass correlation co-efficients (ICCs) for agreement improved after applying the adjustment rule to venous pH (0.7505 to 0.9454) and pCO2 (0.4354 to 0.741). Bland Altman showed bias (and limits of agreement) for pH: 0.008 (-0.04 to + 0.057), pCO2: -3.52 (-9.68 to +2.65), lactate: -0.10 (-0.51 to +0.30), HCO3 (-): -2.3 (-5.11 to +0.50) and BE: -0.80 (-3.09 to +1.49).

Conclusion: ABG and aVBG samples showed strong correlation, acceptable mean differences and improved agreement (high ICC) after adjusting the VBG. Hence, it can be promising to use trend values of VBG instead of ABG in conjunction with a correction factor under stable haemodynamic conditions.

No MeSH data available.


Related in: MedlinePlus

(a) Correlation between adjusted central venous blood gas and arterial blood gas values and linear regression with 95% confidence interval lines on both sides for bicarbonate. (b) Bland Altman bias plots of adjusted central venous blood gas and arterial blood gas for bicarbonate showing mean difference and 95% limits of agreement (AHCO3− = arterial bicarbonate, VHCO3− = central venous bicarbonate)
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Figure 4: (a) Correlation between adjusted central venous blood gas and arterial blood gas values and linear regression with 95% confidence interval lines on both sides for bicarbonate. (b) Bland Altman bias plots of adjusted central venous blood gas and arterial blood gas for bicarbonate showing mean difference and 95% limits of agreement (AHCO3− = arterial bicarbonate, VHCO3− = central venous bicarbonate)

Mentions: Linear regression analysis was then used to create a graphic representation of this relationship with the formula of the "best fit" line allowing the arterial pH, pCO2, lactate, HCO3− and BE values to be calculated from the adjusted central venous pH, pCO2, lactate, HCO3− and BE values respectively [Figures 1a, 2a, 3a, 4a and 5a]. The co-efficient of determination (r2) is the proportion of variation in the dependent variable (arterial) explained by a linear regression model using the independent variable (venous). For all analysis, P <0.05 was considered statistically significant.


Evaluation of adjusted central venous blood gases versus arterial blood gases of patients in post-operative paediatric cardiac surgical intensive care unit.

Singh NG, Prasad SR, Manjunath V, Nagaraja PS, Adoni PJ, Gopal D, Jagadeesh AM - Indian J Anaesth (2015)

(a) Correlation between adjusted central venous blood gas and arterial blood gas values and linear regression with 95% confidence interval lines on both sides for bicarbonate. (b) Bland Altman bias plots of adjusted central venous blood gas and arterial blood gas for bicarbonate showing mean difference and 95% limits of agreement (AHCO3− = arterial bicarbonate, VHCO3− = central venous bicarbonate)
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4645349&req=5

Figure 4: (a) Correlation between adjusted central venous blood gas and arterial blood gas values and linear regression with 95% confidence interval lines on both sides for bicarbonate. (b) Bland Altman bias plots of adjusted central venous blood gas and arterial blood gas for bicarbonate showing mean difference and 95% limits of agreement (AHCO3− = arterial bicarbonate, VHCO3− = central venous bicarbonate)
Mentions: Linear regression analysis was then used to create a graphic representation of this relationship with the formula of the "best fit" line allowing the arterial pH, pCO2, lactate, HCO3− and BE values to be calculated from the adjusted central venous pH, pCO2, lactate, HCO3− and BE values respectively [Figures 1a, 2a, 3a, 4a and 5a]. The co-efficient of determination (r2) is the proportion of variation in the dependent variable (arterial) explained by a linear regression model using the independent variable (venous). For all analysis, P <0.05 was considered statistically significant.

Bottom Line: Central venous catheters are in situ in most of the intensive care unit (ICU) patients, which may be an alternative for determining acid-base status and can reduce complications from prolonged arterial cannulation.ABG and aVBG samples showed strong correlation, acceptable mean differences and improved agreement (high ICC) after adjusting the VBG.Hence, it can be promising to use trend values of VBG instead of ABG in conjunction with a correction factor under stable haemodynamic conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiac Anaesthesiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka, India.

ABSTRACT

Background and aims: Central venous catheters are in situ in most of the intensive care unit (ICU) patients, which may be an alternative for determining acid-base status and can reduce complications from prolonged arterial cannulation. The aim of this study was to examine the reliability between adjusted central venous blood gas (aVBG) and arterial blood gas (ABG) samples for pH, partial pressure of carbon-di-oxide (pCO2), bicarbonate (HCO3 (-)), base excess (BE) and lactates in paediatric cardiac surgical ICU.

Methods: We applied blood gas adjustment rule, that is aVBG pH = venous blood gas (VBG) pH +0.05, aVBG CO2 = VBG pCO2 - 5 mm Hg from the prior studies. In this study, we validated this relationship with simultaneous arterial and central venous blood obtained from 30 patients with four blood sample pairs each in paediatric cardiac surgical ICU patients.

Results: There was a strong correlation (R i.e., Pearson's correlation) between ABG and aVBG for pH = 0.9544, pCO2 = 0.8738, lactate = 0.9741, HCO3 (-) = 0.9650 and BE = 0.9778. Intraclass correlation co-efficients (ICCs) for agreement improved after applying the adjustment rule to venous pH (0.7505 to 0.9454) and pCO2 (0.4354 to 0.741). Bland Altman showed bias (and limits of agreement) for pH: 0.008 (-0.04 to + 0.057), pCO2: -3.52 (-9.68 to +2.65), lactate: -0.10 (-0.51 to +0.30), HCO3 (-): -2.3 (-5.11 to +0.50) and BE: -0.80 (-3.09 to +1.49).

Conclusion: ABG and aVBG samples showed strong correlation, acceptable mean differences and improved agreement (high ICC) after adjusting the VBG. Hence, it can be promising to use trend values of VBG instead of ABG in conjunction with a correction factor under stable haemodynamic conditions.

No MeSH data available.


Related in: MedlinePlus