Comparison of superior vena cava and femoroiliac vein pressure according to intra-abdominal pressure.

Abstract

Previous studies have shown a good agreement between central venous pressure (CVP) measurements from catheters placed in superior vena cava and catheters placed in the abdominal cava/common iliac vein. However, the influence of intra-abdominal pressure on such measurements remains unknown.
We conducted a prospective, observational study in a tertiary teaching hospital. We enrolled patients who had indwelling catheters in both superior vena cava (double lumen catheter) and femoroiliac veins (dialysis catheter) and into the bladder. Pressures were measured from all the sites, CVP, femoroiliac venous pressure (FIVP), and intra-abdominal pressure.
A total of 30 patients were enrolled (age 62 ± 14 years; SAPS II 62 (52-76)). Fifty complete sets of measurements were performed. All of the studied patients were mechanically ventilated (PEP 3 cmH20 (2-5)). We observed that the concordance between CVP and FIVP decreased when intra-abdominal pressure increased. We identified 14 mmHg as the best intra-abdominal pressure cutoff, and we found that CVP and FIVP were significantly more in agreement below this threshold than above (94% versus 50%, P = 0.002).
We reported that intra-abdominal pressure affected agreement between CVP measurements from catheter placed in superior vena cava and catheters placed in the femoroiliac vein. Agreement was excellent when intra-abdominal pressure was below 14 mmHg.

Full text

Page 1

RESEARCHOpen Access
Comparison of superior vena cava and
femoroiliac vein pressure according to intra-
abdominal pressure
Hafid Ait-Oufella1,2,4,5,6*, Pierre-Yves Boelle3,4,5, Arnaud Galbois1, Jean-luc Baudel1, Dimitri Margetis1, Mikael Alves1,
Georges Offenstadt1,4,5, Eric Maury1,4,5and Bertrand Guidet1,4,5
Abstract
Background: Previous studies have shown a good agreement between central venous pressure (CVP)
measurements from catheters placed in superior vena cava and catheters placed in the abdominal cava/common
iliac vein. However, the influence of intra-abdominal pressure on such measurements remains unknown.
Methods: We conducted a prospective, observational study in a tertiary teaching hospital. We enrolled patients
who had indwelling catheters in both superior vena cava (double lumen catheter) and femoroiliac veins (dialysis
catheter) and into the bladder. Pressures were measured from all the sites, CVP, femoroiliac venous pressure (FIVP),
and intra-abdominal pressure.
Results: A total of 30 patients were enrolled (age 62±14 years; SAPS II 62 (52–76)). Fifty complete sets of
measurements were performed. All of the studied patients were mechanically ventilated (PEP 3 cmH20 (2–5)). We
observed that the concordance between CVP and FIVP decreased when intra-abdominal pressure increased. We
identified 14 mmHg as the best intra-abdominal pressure cutoff, and we found that CVP and FIVP were significantly
more in agreement below this threshold than above (94% versus 50%, P=0.002).
Conclusions: We reported that intra-abdominal pressure affected agreement between CVP measurements from
catheter placed in superior vena cava and catheters placed in the femoroiliac vein. Agreement was excellent when
intra-abdominal pressure was below 14 mmHg.
Keywords: Intensive unit care, Central venous pressure, Superior vena cava, Femoroiliac vena, Intra-abdominal
pressure
Background
Central venous pressure (CVP) is a hemodynamic par-
ameter required in critically ill patients [1]. Convention-
ally, venous access is preferred via the internal jugular or
subclavian vein with measurements of CVP in the super-
ior vena cava above the right atrium. However, this ap-
proach is potentially hazardous, risking carotid artery
puncture, pneumothorax, and neurologic damage [2,3].
Central venous access also may be achieved via the fem-
oral vein by positioning the catheter in the abdominal
cava/common iliac vein or in the right atrium depending
of the length of the catheter. Nahum et al. reported a
good correlation and agreement between CVP measure-
ments from catheter placed in the right atrium and
catheters placed in the abdominal cava/common iliac
vein in children [4]. Joynt’s group confirmed these data
in adults. They showed an equally good agreement be-
tween measurement of CVP in the superior vena cava
above the right atrium and measurements recorded from
long (40–70 cm) and short (15–20 cm) catheters placed
in the inferior vena cava, respectively, close to right
atrium [5] and in the common iliac vein [6]. Moreover,
the mode of mechanical ventilation did not affect overall
agreement between measurements [7].
In the intensive unit care (ICU), various clinical condi-
tions, such as post-abdominal surgery, trauma, sepsis,
pancreatic, and burns can lead to an increase of the
* Correspondence: hafid.aitoufella@sat.aphp.fr
1AP-HP, Hôpital Saint-Antoine, Service de réanimation médicale, Paris 75571
Cedex 12, France
2Inserm U970, Paris Research Cardiovascular Center, Paris, France
Full list of author information is available at the end of the article
© 2012 Ait-Oufella et al.; licensee Springer. This is an Open Access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction
in any medium, provided the original work is properly cited.
Ait-Oufella et al. Annals of Intensive Care 2012, 2:21
http://www.annalsofintensivecare.com/content/2/1/21

Page 2

intra-abdominal pressure [8]. The worst threatening
condition, called abdominal compartment syndrome,
alters global hemodynamic status, organ perfusion
mainly through a decrease of venous return [9] and can
cause death. We hypothesized that intra-abdominal
hypertension could alter measurement of venous pres-
sure and modify agreement between measurements from
catheter placed in the superior vena cava, reflecting
CVP, and catheter placed in the femoroiliac vein. We
conducted a prospective, observational study to compare
pressure measured in the superior vena cava (CVP) and
in the femoroiliac vein (FIVP) according to intra-
abdominal pressure.
Methods
This study was classified as observational by the institu-
tional review board of our hospital (Comité de Protection
des Personnes de l’Hôpital Saint-Antoine). After obtain-
ing oral consent from the patients or from their nearest
relatives, we included consecutive patients who had
indwelling catheters in both the superior vena cava and
femoroiliac veins. Patients were under mechanical venti-
lation (assisted control ventilation mode) and adapted to
the ventilator. Standard double-lumen catheters and
renal dialysis catheters (20-cm long) were all used in this
study to measure respectively superior vena cava pres-
sure (CVP) and femoroiliac venous pressure (FIVP). All
catheters used in this study were already in place and jus-
tified by the patient’s clinical condition; no catheter was
specifically inserted for the sole purpose of the study.
Patients could be included twice if the second set of mea-
surements was performed more than 7 days after the first
inclusion. Venous pressure measurements were recorded
at both sites by using the same pressure transducer. Be-
fore the measurements, a zero pressure calibration dur-
ing the tele-expiratory period was performed on each
catheter, with the patient in a supine position. All pres-
sure measurements (intra-abdominal and venous) were
repeated four times at 5-min intervals during the tele-
expiratory period, and mean values were calculated.
Intra-abdominal pressure was measured indirectly by
measuring the pressure within the bladder, as described
by Cheatham et al. [10]. Briefly, two, three-way stop-
cocks are connected serially to a disposable pressure
transducer. A standard intravenous infusion set is con-
nected to 1 L of sterile normal saline and attached to
one stopcock, and a 20-mL syringe is attached to the
second stopcock. An 18-gauge angiocatheter is inserted
into the culture aspiration port of the urinary drainage
tube using aseptic technique. The needle is removed,
leaving the plastic infusion catheter in place. The infu-
sion catheter is attached to the first stopcock via pres-
sure tubing. The system is flushed with normal saline
and the pressure transducer “zeroed” at the level of the
symphysis pubis. To measure intra-abdominal pressure,
the urinary drainage tube is clamped immediately distal
to the catheter. The stopcocks are turned off to the pa-
tient and to the pressure transducer. Normal saline is
aspirated from the intravenous bag using the 20-mL syr-
inge. The first stopcock is turned on to the patient, and
the normal saline (20 ml) is instilled into the bladder
through the urinary catheter [11]. The stopcocks are
then turned off to the syringe and intravenous tubing.
The clamp on the urinary drainage tubing is momentar-
ily released to ensure that all air is flushed from the
urinary catheter. The patient’s intra-abdominal pressure
is then measured at end-expiration. The clamp is
removed and the bladder allowed to drain.
Exclusion criteria were mechanical ventilation mode
different than ACV and agitation, and disadaptation to
the ventilator that troubled superior vena cava pressure
measurements.
Statistical analysis
Data were expressed as mean±standard deviation or
median (interquartile range) in the case of non-Gaussian
distribution. The intraclass correlation coefficient (ICC)
was used to assess concordance between FIVP and CVP.
ICC values >0.8 correspond to an “excellent” agreement
(Landis and Koch). To assess the impact of intra-
abdominal pressure, the ICC was calculated for subsets
of patients with less than a given intra-abdominal pres-
sure threshold. The threshold value was systematically
varied from x to y to find the best intra-abdominal pres-
sure cutoff; x was the lower intra-abdominal pressure
obtained in this study and y the highest. After identifica-
tion of the best intra-abdominal pressure cutoff, the ICC
was compared for observations below and above the
threshold using a bootstrap-based test. Finally, in obser-
vations where the intra-abdominal pressure was less
than the optimal cutoff, a linear regression model was
used to predict CVP from FIVP.
We hypothesized that agreement would be very good
in practice (ICC ~90%) when intra-abdominal pressure
was low. Including 15 patients was sufficient to get a
lower 95% confidence interval (CI) >70%. Assuming that
the prevalence of large IAP could be up to 50%, we fi-
nally included 30 patients. All analyses were made by
using R software (v 2.9.1; http://cran.r-project.org).
Results
Between February 2009 and August 2010, 30 consecu-
tive patients were enrolled, and 50 complete sets of
measurements were performed (Table 1). All patients
had a subclavicular or jugular catheter for drug infusion
and a 20-cm long, femoral catheter for renal dialysis.
The position of catheter in the superior vena cava was
confirmed by radiography, within 5 cm to the junction
Ait-Oufella et al. Annals of Intensive Care 2012, 2:21
http://www.annalsofintensivecare.com/content/2/1/21
Page 2 of 5

Page 3

vena cava-right atrium. We observed during a prelimin-
ary study using abdominal CT scan that 20-cm long,
femoral catheters were placed at the junction iliac vein/
inferior vena cava. All of the studied patients were
mechanically ventilated and had acute renal failure re-
quiring dialysis. In the group with a PIA ≥14 mmHg,
patients had mostly intra-abdominal infection or ab-
dominal surgery, whereas in the group of patients with
a PIA <14 mmHg, admission diagnoses were various,
such as lung infection and cardiac arrest (Table 2).
Among patients admitted for septic shock, the propor-
tion of cirrhosis with ascites was more important in the
group with high IAP (5/8 versus 3/12 patients). Severity
was high as illustrated by high SAPS II.
Interestingly, we observed that the concordance be-
tween CVP and FIVP measurements decreased when
intra-abdominal pressure increased (Figure 1). The ICC
was 0.94 (95% CI [0.89-0.97]), corresponding to excel-
lent agreement on the Landis and Koch scale, when
consideringpatientswith
<14 mmHg. The ICC reduced to 0.77 (95% CI [0.41-
0.94]) when patients with intra-abdominal pressure
<15 mmHg were added, and concordance decreased
even more as patients with larger intra-abdominal
pressure values were considered (Figure 1). Therefore,
concordance between CVP and FIVP was best when
IAP was <14 mmHg. CVP and FIVP were significantly
more in agreement below this threshold than above
(0.94 versus 0.5, P=0.002; Figure 2).
As expected from the large concordance, CVP was
very well predicted by FIVP in patients with intra-
abdominal pressure <14 mmHg. The linear regression
equation was CVP=1.01 FIVP (R2=0.99; Figure 3).
intra-abdominalpressure
Discussion
Our results showed that the FIVP could be used to esti-
mate correctly CVP and confirmed previous published
studies in adults and children in ICU [4,5]. However,
we pointed out that FIVP measurement accuracy had
to be interpreted according to the intra-abdominal
pressure. When intra-abdominal pressure was inferior
Table 1 Characteristic of included patients
Patients (n)30
Weight (kg)
BMI (kg/m2)
80±16
29.8±6.3
Gender (M/F)15/15
Age (yr)62±14
SAPS II 62 (52–76)
Dialysis, n (%)30 (100)
Vasopressors, n (%) 27 (90)
Plateau pressure (cmH20) 20 (18–25)
PEEP (cm H20)3 (2–5)
Data are expressed as mean±standard deviation or median (first–third
quartile) according to distribution. SAPS II, Simplified Acute Physiology Score II;
PEEP, positive end-expiratory pressure, BMI, body mass index (calculated as
mass (kg)/(height (m)2).
Table 2 Causes of admission according to the intra-
abdominal pressure (IAP)
PIA <14 mmHgPIA ≥14 mmHg
Septic shockSeptic shock
Lung (7) Lung (2)
Abdomen (4) Abdomen (4)
Soft tissue (1) Urinary tract (1)
Urinary tractus (1) Unlocalized bacteriemia (1)
Endocarditis (1)
Unlocalized bacteriemia (1)Liver transplantation (2)
Acute alcoholic hepatitis (2)
Acute alcoholic hepatitis (2)
Cardiac arrest (4) Gut occlusion (1)
Cardiogenic shock (3)Mesenteric infarction (1)
HELP syndrome (2)
Self poisoning (2)
Other (8)
Intra abdominal pressure (mmHg)
Figure 1 Intraclass correlation coefficient (ICC) for patients with
intra-abdominal pressure less than a given value (dots for ICC
values and lines for 95% confidence interval). When patients
with high intra-abdominal pressure were added, ICC decreased.
Ait-Oufella et al. Annals of Intensive Care 2012, 2:21
http://www.annalsofintensivecare.com/content/2/1/21
Page 3 of 5

Page 4

to 14 mmHg, FIVP predicted very well CVP. When
intra-abdominal pressure was more than 14 mmHg,
corresponding to the first stage of intra-abdominal
hypertension, FIVP did not reflect accurately CVP
anymore. The difference could be large (median 4
(range 0–18)) and was always in the direction FIVP>
CVP. Interestingly, this cutoff was close to the thresh-
old (12 mmHg) that defines intra-abdominal hyperten-
sion according to the International Conference of
Experts on Intra-abdominal Hypertension and Abdom-
inal Compartment Syndrome [12]. It is not exactly the
same value of cutoff probably because the studied
population size was limited. In case of severe intra-
abdominal hypertension (IAP>20 mmHg), De Keule-
naer et al. [13] recently reported that FIVP could be
used as a surrogate measure of IAP, illustrating the
link between FIVP and IAP. The consequences during
severe infections, if physicians followed Survival Sepsis
Campaign Guidelines for fluid administration, could be
an underestimation of hypovolemia in these patients, a
delay for fluid challenge and could in fine worsen
patient’s prognosis [14]. The effects of intra-abdominal
pressure on FIVP measurements are relevant, because
abdominal compartment syndrome is not rare in ICU
(from 1–20% according to published data) and is fre-
quently underestimated [15].
More generally, this study questions about the effects
of intra-abdominal pressure on others hemodynamic
tools used in the clinical setting to evaluate volemia. For
example, passive leg raising was reported by several
groups to be a good predictor of fluid responsiveness
[16]. However, Mahjoub et al. showed that the passive
left raising maneuver did not accurately predict fluid re-
sponsiveness in patients with intra-abdominal hyperten-
sion [17].
Intra abdominal pressure (mmHg)
> _
Figure 2 Intraclass correlation coefficient according to intra-
abdominal pressure cutoff. Less than 14 mmHg, agreement
between FIVP and CVP measurements was excellent and better than
situations when intra-abdominal pressure was >14 mmHg (0.94
versus 0.5, P=0.002). FIVP, femoroiliac venous pressure; CVP, central
venous pressure. Boxes show first and third quartiles, with the
median as a thick line. Whiskers extend to 1.5 interquartile range
(Q75-Q25).
FIVP (mmHg)
CVP (mmHg)
IAP<14mmHg
IAP 14mmHg
<_
Figure 3 Less than 14 mmHg (black circle) FIVP reflected CVP, the linear regression equation was CVP=1.01 FIVP. Greater than
14 mmHg (white circle), FIVP overestimated CVP. FIVP, femoroiliac venous pressure; CVP, central venous pressure.
Ait-Oufella et al. Annals of Intensive Care 2012, 2:21
http://www.annalsofintensivecare.com/content/2/1/21
Page 4 of 5

Page 5

Our study has several limitations. It is a monocentric
study and results have to be confirmed in a larger popu-
lation. Nevertheless, although the size of this preliminary
study was not very large, it was sufficient to highlight
significantresults. Intra-abdominal
recorded indirectly by using intra-bladder pressure, but
this technique had achieved a widespread adoption
worldwide. Finally, our studied population did not have
severe pulmonary disease: median PEEP was 3 cmH2O
(2–5) and median plateau pressure was 20 cmH2O (18–
25). Therefore, our data could not be extrapolated to
clinical situations with lung injury and/or high PEEP
and/or high intrathoracic pressure, but we could specu-
late that, in these situations, agreement between central
and femoroiliac venous pressure would be strongly
altered. The impact of increased intra-abdominal pres-
sure on agreement between CVP and FIVP was docu-
mented using short catheters (20-cm long) and could
not be extrapolated to measurements obtained using
longer catheters, which tip arise right atrium.
pressure was
Conclusions
We reported the effects of intra-abdominal pressure on
venouspressuremeasurements.
abdominal pressure was inferior to 14 mmHg, femoroi-
liac pressure predicted very well central venous pressure.
However, when intra-abdominal pressure is >14 mmHg,
femoroiliac pressure did not and intra-class correlation
coefficient decreased from 94% to 50%.
When theintra-
Competing interest
The authors had no conflict of interest.
Author details
1AP-HP, Hôpital Saint-Antoine, Service de réanimation médicale, Paris 75571
Cedex 12, France.2Inserm U970, Paris Research Cardiovascular Center, Paris,
France.3AP-HP, Hôpital Saint-Antoine, Service de santé publique, Paris
F-75012, France.4Université Pierre et Marie Curie-Paris 6, Paris, France.
5Inserm U707, Paris F-75012, France.6Service de Réanimation médicale,
Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, Paris 75571 cedex
12, France.
Authors’ contributions
HAO, GO, EM and BG designed the study. HAO and PYB performed the
statistical analysis. HAO, AG, JLB, DM and MA participated to patients’
inclusion. All authors read and approved the final manuscript.
Received: 17 February 2012 Accepted: 28 June 2012
Published: 28 June 2012
References
1. Dellinger RP, Levy MM, Carlet JM, Bion J, Parker MM, Jaeschke R, Reinhart K,
Angus DC, Brun-Buisson C, Beale R, et al: Surviving Sepsis Campaign:
international guidelines for management of severe sepsis and septic
shock: 2008. Crit Care Med 2008, 36:296–327.
2. Agee KR, Balk RA: Central venous catheterization in the critically ill
patient. Crit Care Clin 1992, 8:677–686.
3.Lloyd TR, Donnerstein RL, Berg RA: Accuracy of central venous pressure
measurement from the abdominal inferior vena cava. Pediatrics 1992,
89:506–508.
4.Nahum E, Dagan O, Sulkes J, Schoenfeld T: A comparison between
continuous central venous pressure measurement from right atrium and
abdominal vena cava or common iliac vein. Intensive Care Med 1996,
22:571–574.
Joynt GM, Gomersall CD, Buckley TA, Oh TE, Young RJ, Freebairn RC:
Comparison of intrathoracic and intra-abdominal measurements of
central venous pressure. Lancet 1996, 347:1155–1157.
Ho KM, Joynt GM, Tan P: A comparison of central venous pressure and
common iliac venous pressure in critically ill mechanically ventilated
patients. Crit Care Med 1998, 26:461–464.
Dillon PJ, Columb MO, Hume DD: Comparison of superior vena caval and
femoroiliac venous pressure measurements during normal and inverse
ratio ventilation. Crit Care Med 2001, 29:37–39.
Malbrain ML, IE De laet, De Waele JJ: IAH/ACS: the rationale for
surveillance. World J Surg 2009, 33:1110–1115.
Cheatham ML: Abdominal compartment syndrome. Curr Opin Crit Care
2009, 15:154–162.
Cheatham ML, Safcsak K: Intra-abdominal pressure: a revised method for
measurement. J Am Coll Surg 1998, 186:594–595.
Chiumello D, Tallarini F, Chierichetti M, Polli F, Li Bassi G, Motta G, Azzari S,
Carsenzola C, Gattinoni L: The effect of different volumes and
temperatures of saline on the bladder pressure measurement in critically
ill patients. Crit Care 2007, 11:R82.
Malbrain ML, Cheatham ML, Kirkpatrick A, Sugrue M, Parr M, De Waele J,
Balogh Z, Leppaniemi A, Olvera C, Ivatury R, et al: Results from the
International conference of experts on intra-abdominal hypertension
and abdominal compartment syndrome. I. Definitions. Intensive Care Med
2006, 32:1722–1732.
De Keulenaer BL, Regli A, Dabrowski W, Kaloiani V, Bodnar Z, Cea JI, Litvin
AA, Davis WA, Palermo AM, De Waele JJ, Malbrain ML: Does femoral
venous pressure measurement correlate well with intrabladder pressure
measurement? A multicenter observational trial. Intensive Care Med 2011,
37:1620–1627.
Rivers E, Nguyen B, Havstad S, Ressler J, Muzzin A, Knoblich B, Peterson E,
Tomlanovich M: Early goal-directed therapy in the treatment of severe
sepsis and septic shock. N Engl J Med 2001, 345:1368–1377.
Malbrain ML, Vidts W, Ravyts M, De Laet I, De Waele J: Acute intestinal
distress syndrome: the importance of intra-abdominal pressure. Minerva
Anestesiol 2008, 74:657–673.
Monnet X, Teboul JL: Volume responsiveness. Curr Opin Crit Care 2007,
13:549–553.
Mahjoub Y, Touzeau J, Airapetian N, Lorne E, Hijazi M, Zogheib E, Tinturier F,
Slama M, Dupont H: The passive leg-raising maneuver cannot accurately
predict fluid responsiveness in patients with intra-abdominal
hypertension. Crit Care Med 2010, 38:1824–1829.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
doi:10.1186/2110-5820-2-21
Cite this article as: Ait-Oufella et al.: Comparison of superior vena cava
and femoroiliac vein pressure according to intra-abdominal pressure.
Annals of Intensive Care 2012 2:21.
Submit your manuscript to a
journal and benefi t from:
7 Convenient online submission
7 Rigorous peer review
7 Immediate publication on acceptance
7 Open access: articles freely available online
7 High visibility within the fi eld
7 Retaining the copyright to your article
Submit your next manuscript at 7 springeropen.com
Ait-Oufella et al. Annals of Intensive Care 2012, 2:21
http://www.annalsofintensivecare.com/content/2/1/21
Page 5 of 5