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Table 4 Comparison of bedside Pmcf measurement techniques

From: Estimating mean circulatory filling pressure in clinical practice: a systematic review comparing three bedside methods in the critically ill

 

Pmcf hold

Pmcf arm

Pmcf analogue

CO = (Pmcf CVP)/RVR

Pa = Pv

Pmcf = axCVP + bxMAP + cxCO

Applicability to a broad patient population

−

±

±

 

Restricted to fully sedated and mechanically ventilated patients

In theory applicable in all patients (sedated or awake) with an radial artery catheter

In theory applicable in all patients (sedated or awake)

 

Restricted to patients without a contraindication for inspiratory holds (such as COPD with bullae)

 

Continuous and accurate CO, MAP and CVP measurements needed

 

Continuous and accurate CO and CVP measurements needed

 

Not suitable in cardiac arrhythmia

 

Not suitable in cardiac arrythmia

  

Accuracy

+

+

−

 

Values interchangeable with Pmcf arm

Values interchangeable with Pmcf hold

Values significantly lower than derived with Pmcf hold

 

When sedated baroreflex probably of little influence

Dependent on time of measurement: > Pa and Pv equilibration. < hypoxia-induced vasodilatation

Pmcf analogue can be transformed to Pmcf hold values (constant error)

 

Mechanical ventilation may overestimate Pmcf value

Possible influence rapid cuff inflator on reflex mechanism altering Pmcf value in non-sedated patients. This is not studied

Mathematical coupling and the equation is based on assumptions that may not be generalizable to all patient populations in ICU

Precision

?

+

?

 

Not studied

No significant differences during repeated measurements. LSC for a single measurement is 14%

Not studied

Outcome operator independent

−

±

+

 

Inspiratory holds

Timing of measurement

CVP transducer position and CO measurement technique

 

CVP transducer position and CO measurement technique

  
 

Extrapolation of curve

  

Responding time

−

+

+

 

> 4 min

30–60 s

Fast, no exact times mentioned

Costs

−

+

+

 

Theoretically no extra devices needed than standard present in ICU

Rapid Cuff Inflator (Hokanson E20, Bellevue, Washington, USA) = 3000 euro

Navigatorâ„¢ (Applied Physiology, Pty Ltd, Sydney, Australia)

   

Price unknown

Risk of complications

+

±

−

 

No complications reported in published studies. In theory:

No complications reported in published studies. In theory:

No complications reported in published studies. In theory:

 

Barotrauma from inspiratory holds

In sedated patients attention should be paid deflating the rapid cuff before hypoxemia-induced damage can occur

Complications associated with central venous catheters and CO measurement

 

Severe hemodynamic instability induced by inspiratory holds

In awake patients local pain could be caused by inflating the rapid cuff inflator

 
 

Complications associated with central venous catheters and CO measurement

  
  1. CO cardiac output, CVP central venous pressure, RVR resistance to venous return, MAP mean arterial pressure, Pa arterial pressure, Pv venous pressure (the latter two measured in the arm)