Utility of central venous pressure measurement in renal transplantation: Is it evidence based?

Table 1 Factors affecting the measured central venous pressure reading[9]

Central venous blood volume	Venous return/cardiac output Total blood volume Regional vascular tone
Compliance of central compartment	Vascular tone Right ventricular compliance: Myocardial disease Pericardial disease Tamponade
Tricuspid valve disease	Stenosis Regurgitation
Cardiac rhythm	Junctional rhythm Atrial fibrillation Atrio-ventricular dissociation
Reference level of transducer	Positioning of patient
Intrathoracic pressure	Respiration Intermittent positive pressure ventilation Positive end-expiratory pressure Tension pneumothorax

Table 2 Advantages and limitations of some commercially available (minimally invasive) cardiac output monitoring[19,20]

Modality	Examples	Advantages	Limitations
Pulse wave analysis	LiDCOrapid™ and FloTrac/Vigileo™	Requires only arterial line; Beat-by-beat CO monitoring (this may help to evaluate response to IV fluids). - Validated by clinical studies in different medical and surgical conditions	Presence of arterial line with optimum waveform signal is a prerequisite; Accuracy may be reduced by sever arrhythmia; Needs frequent recalibration during periods of hemodynamic Instability
Lithium dilution	LiDCOplus™	Simple technique (can use peripheral arterial line); Continuous CO monitoring	Arterial line required; Accuracy affected by some neuromuscular blocking drugs; Lithium chloride is contraindicated in patients undergoing treatment with lithium salts
Electrical bioimpedance	BioZ®	Completely non-invasive	Numerous mathematical assumptions; Limited validity in patients with dysrhythmias
Partial CO2 rebreathing	NICO™	Easy to set up	Requires intubation and mechanical ventilation with minimal gas exchange abnormalities and fixed ventilator settings; Accuracy decreased with haemodynamic instability
Pulsed dye densitometry	DDG-330®	Non-invasive	Intermittent assessment; Accuracy may be affected by vasoconstriction, movement of the sensor and interstitial oedema

CO: Cardiac output; OR: Operating room.

Table 3 Dynamic evaluation of fluid status in comparison to conventional approach

Author	Patients No.	Study group	Conclusion
Berkenstadt et al[21], 2001	15	Patients undergoing brain surgery	SVV could predict fluid responsiveness to even a small volume loading of 100 mL of 6% hydroxyethyl starch given for two minutes; There was no correlation between the changes in SV and the values of the CVP and heart rate before or after loading
Rex et al[22], 2004	14	Coronary artery bypass grafting (CABG) patients	The dynamic index SVV allowed real-time monitoring of left ventricular preload. Moreover, it allowed assessing the haemodynamic effect of a fluid challenge; Other preload variables (i.e., PAOP, CVP, LVEDAI and ITBI) failed to predict fluid responsiveness
Preisman et al[23], 2005	18	Coronary artery bypass grafting (CABG) patients	Functional haemodynamic indices were superior to static indicators of cardiac preload in predicting fluid responsiveness; Use of CVP for the evaluation of intravascular volume status, have been found to lack any predictive value
Hofer et al[24], 2005	40	CABG patients	Stroke volume index was significantly correlated with SVV (P < 0.001) and PPV (P < 0.001) only; While CVP failed to have a significant correlation (P = 0.235)
Wiesenack et al[25], 2005	20	CABG patients	Stroke volume index correlated significantly with SVV and PPV derived from pulse contour analysis (P < 0.05) but not with CVP or pulmonary artery wedge pressure
Cannesson et al[26], 2006	18	CABG patients	Left ventricular stroke area measured by transoesophageal echocardiographic automated border detection is not only sensitive to changes in preload but also, can quantify the effects of volume expansion on cardiac output; The difference in CVP reading did not reach statistical significance in the study groups
Lee et al[27], 2007	20	Neurosurgical patients	Corrected flow time by oesophageal Doppler and PPV are better than CVP and LVEDAI in predicting fluid responsiveness
Cannesson et al[28], 2007	25	CABG patients	ΔPOP can predict response to volume expansion as well as quantify the effects of volume expansion on hemodynamic parameters during cardiac surgery; There was no statistically significant relation between CVP and increase in cardiac index after volume expansion
Belloni et al[29], 2008	19	CABG patients	Their results confirm the ability of SVV (P = 0.0005) and PPV (P = 0.001) to predict fluid responsiveness in ventilated patients during cardiac surgery No significant differences were found in mean LVEDA and CVP before and after fluid administration
Biais et al[30], 2008	35	Postoperative period of liver transplantation	SVV and PPV measurement by arterial waveform analysis can be used to predict the effects of volume expansion in mechanically ventilated patients after liver transplantation; The failure of CVP and PAOP to predict fluid responsiveness agrees with increasing evidence that static preload indicators are not suitable for functional haemodynamic monitoring
Hofer et al[31], 2008	40	CABG patients	Conventional static preload parameters failed to reflect the fluid status or to predict fluid responsiveness. CVP is therefore unsuitable for predicting ventricular response to fluid loading; SVV measured by the FloTrac™/Vigileo™ and the PiCCOplus™ systems exhibited similar performances regarding predicting fluid responsiveness
de Waal et al[32], 2009	18	CABG patients	SVV of > 8% can predict fluid responsiveness with 100% sensitivity and 78% specificity, while PPV ≥ 10% can identify fluid-responders with 64% sensitivity and 100% specificity; CVP readings were not better in predicting fluid responsiveness than random chance
Cannesson et al[33], 2009	25	CABG patients	SVV of 10% helped in discrimination of responders to volume expansion with an 82% sensitivity and 88% specificity; SVV may be a potential alternative to DeltaPP which is an accurate predictor of fluid responsiveness in ventilated patients; SVV was significantly a better predictor of fluid responsiveness than CVP and PCWP in this study
Zimmermann et al[34], 2010	20	Elective major abdominal surgery	Both SVV and PVI are valid indicators of fluid responsiveness in ventilated patients during major abdominal surgery; CVP did not adequately reflect circulating blood volume and failed to predict fluid responsiveness in this study
Desgranges et al[35], 2011	28	CABG patients	PVI can predict fluid responsiveness during general anaesthesia whatever the site of measurement in the operating room (the finger, the ear, and the forehead); PCWP and CVP showed no significant difference between responders and non-responders
Shin et al[36], 2011	33	Elective living donor liver transplantation	Femoral SVV > 8% can predict responders to fluid loading with a specificity of 80% and a sensitivity of 89%; CVP and PAOP did not correlate with the changes in the cardiac index that occurred with a fluid challenge
Broch et al[37], 2011	81	CABG patients	SVV (P = 0.002) and PPV (P < 0.0001) were found to be reliable indicators for fluid responsiveness unlike CVP (P = 0.13) that failed to predict it; PVI ability to predict fluid responsiveness is limited in the presence of low perfusion indices
Cannesson et al[38], 2011	413	Multicentre study of different abdominal and cardiac surgeries	PPV [AUC 0.89 (0.86; 0.92)] is superior to CVP [AUC 0.57 (0.54; 0.59)] in prediction of fluid responsiveness (P < 0.001)
Yazigi et al[39], 2012	60	CABG patients older than 70 yr	PPV is a reliable predictor of fluid responsiveness while CVP and PAOP were not better than a random chance in predicting the response to fluid; PPV reliability was not affected by the decreased arterial compliance and increased arterial stiffness related to aging
Bogović et al[40], 2017	24	Major (abdominal or trauma) surgery	The study stressed on the inability of CVP to provide a valid evaluation of the preload; SVV and PPV monitored by LiDCO™ were better alternatives for preload assessment

AUC: Area under the receiver operator characteristic curve; CVP: Central venous pressure; DeltaPP: Respiratory variations in arterial pulse pressure; ITBI: Intrathoracic blood volume index; LVEDA: Left ventricular end-diastolic area; LVEDAI: Left ventricular end-diastolic area index; PAOP: Pulmonary artery occlusion pressure; PCWP: Pulmonary capillary wedge pressure; PPV: Pulse pressure variation; PVI: Pleth variability index; SV: Stroke volume; SVV: Stroke volume variation; ΔPOP: Respiratory variations in the pulse oximetry plethysmographic waveform amplitude.