and the popular measure of body size for hemodynamic measurements
is the body surface area (BSA), which can be determined with the follow-
ing simple equation (17).
BSA (m
2
)
=
Ht (cm)
+
Wt (kg) – 60/100
(8.3)
Why not use body weight to adjust for body size? BSA was chosen for
hemodynamic measurements because cardiac output is linked to meta-
bolic rate, and the basal metabolic rate is expressed in terms of body sur-
face area. The average-sized adult has a body surface area of 1.7 m
2
.
†
mm Hg/L/min/m
2
Cardiovascular Parameters
The following parameters are used to evaluate cardiac performance and
mean arterial pressure. The normal ranges for these parameters are in-
cluded in Table 8.1. Parameters that are adjusted for body surface area are
identified by the term
index
.
CentralVenous Pressure
When the PA catheter is properly placed, the proximal port of the
catheter should be situated in the right atrium, and the pressure record-
ed from this port should be the right atrial pressure (RAP). As mentioned
previously, the pressure in the right atrium is the same as the pressure in
the superior vena cava, and these pressures are collectively called the
cen-
tral venous pressure
(CVP). In the absence of tricuspid valve dysfunction,
the CVP should be equivalent to the right-ventricular end-diastolic pres-
sure (RVEDP).
CVP
=
RAP
=
RVEDP
(8.4)
Parameter
Abbreviation
Normal Range
Central Venous Pressure
CVP
0 – 5 mm Hg
Pulmonary Artery
PAWP
6 –12 mm Hg
Wedge Pressure
Cardiac Index
CI
2.4 – 4.0 L/min/m
2
Stroke Index
SI
20 – 40 mL/m
2
Systemic Vascular
SVRI
25–30 Wood Units
†
Resistance Index
Pulmonary Vascular
PVRI
1– 2 Wood Units
†
Resistance Index
Oxygen Delivery (Index)
DO
2
520 – 570 mL/min/m
2
Oxygen Uptake (Index)
VO
2
110 –160 mL/min/m
2
Oxygen Extraction Ratio
O
2
ER
0.2 – 0.3
Table 8.1
Hemodynamic and Oxygen Transport Parameters
144
Hemodynamic Monitoring
