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Three Part Question

In [patients requiring central venous pressure monitoring] is [a femoral vein central line as good as a jugular or subclavian line] at [reliability assessing right atrial filling pressure]?

Clinical Scenario

You have been called to the resuscitation room to see a 67 year old woman who has walked out in front of a bus while shopping in town. She has an obvious closed fracture of her left arm and she is complaining of abdominal pain and central neck pain. You elicit from her husband that she has had two heart attacks in the past and the drugs in her handbag are bendrofluazide, frumil, and lisinopril. Her blood pressure is 90/52 and her pulse is 105. You are concerned that she may be hypovolaemic, but you are aware of the dangers of giving too much fluid to a patient with probable heart failure. You elect to insert a central line for central venous pressure monitoring but she has a neck collar on and so you wonder if placing this via the femoral vein would affect your readings.

Search Strategy

Medline 1966-06/03 using the OVID interface
[(exp Central Venous Pressure OR Central Venous pressure.mp) AND (exp Vena Cava, Inferior OR vena cava.mp)] LIMIT to human.

Search Outcome

Out of 141 papers 9 were found to be relevant. These papers are shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Murdoch IA et al, 1994, UK	12 children with cardiac pathology undergoing cardiac catheterisation while on assisted ventilation. Mean age 13mth (range 0.5-56mths) SVC, IVC and right atrial measurements	Observational cohort study	Comparison of IVC pressure readings compared to SVC and right atrial pressures	SVC to IVC readings were all within 1.2mmHg. Right atrial pressure to IVC pressure was always less than 0.7mmHg apart	Young children only, small group of healthy outpatients coming for cardiac catheterisation Supine patients only Range of readings not given
Chait HI et al, 1994, USA	33 paediatric cardiac -surgical patients age 2 days to 9 years. Insertion of femoral venous catheter, and transthoracic right atrial catheter Mechanical and spontaneous ventilation	Observational cohort study	Comparison of right atrial and inferior venal caval pressure	23 of 31 paired patient readings were the same, 5 were within 2mmHg, 3 within 3 mmHg. All spontaneously breathing readings were within 2 mmHg. IVC pressures were a mean of 0.71mmHg higher than RA pressure	Study contained only children with congenital cardiac abnormalities
Yung M et al, 1995, Australia	39 children with both SVC and IVC central venous catheters in place in a paediatric ICU Age range 5 days to 14 years CVP range 3-17mmHg	Observational cohort study	SVC compared to IVC pressure	mean difference 0.33mmHg. 22 of 39 pressure readings were equal. 33 of 39 pressures were within 1mmHg. 37 of 39 pressures were within 2mmHg	Position of femoral lines not verified radiologically and short lines used 3 children spontaneously breathing. 36 ventilated
Reda Z et al, 1995, USA	44 children in ICU with mechanical ventilation Group 1 had no evidence of abdominal distension Group 2 had evidence of abdominal distension	Observational cohort study	SVC pressure compared to IVC pressure		The diagnosis of abdominal distension was entirely subjective No attempt was made to measure intra-abdominal pressure
			Normal abdomen	Mean difference 0.93, max difference 3mmHg (unaffected by high PEEP or mean airway pressures
			Abdominal distension	50% of SVC to IVC measurements were >3mmHg
Nahum E et al, 1996, Israel	9 children in a paediatric ICU. 8 were mechanically ventilated Age 6mths –14yrs Measurement of right atrial pressure and abdominal vena cava or common iliac vein. CVP ranged from 3-30mmHg	Observational cohort study	Right atrial pressure compared to IVC or Common iliac vein pressure	Mean difference 0.22mmHg+/-1.52mmHg. 99.2% of readings were less than 2mmHg apart.	This is a study in children only 1 patient was excluded due to unreliable venous waveform of the right atrial catheter 7 patients had congenital heart defects
			Causes of increased difference	None of Increased CVP, mechanical ventilation and abdominal fluid collection increased difference.
Joynt GM et al, 1996, Hong Kong	19 critically ill patients mechanically ventilated in ICU Femoral catheter placed close to right atrium in IVC Confirmed by chest radiograph	Observational cohort study	SVC pressure compared to IVC pressure.	Mean difference is 0.45mmHg (CI 0.30-0.60)	Patients all supine and ventilated Non-standard – 40-70cm multi-lumen catheters used Interestingly – an intra-abdominal pressure change of 2-22cmH20 did not significantly change the differences observed
			Causes of increased difference	Small tendency for increased PEEP and Mean airway pressure to increase observed difference
Ho KM et al, 1998, Hong Kong	20 patients who were mechanically ventilated in ICU Simultaneous monitoring of SVC and common iliac venous pressure, (at L5) using commonly available 20cm central venous catheters SVC range 3-36mmHg	Observational cohort study	SVC pressure and common iliac vein pressure (CIVP)	Mean difference 0.1mmHg 1.06(SD)mmHg	Patients all supine and ventilated
Yazigi A et al, 1996, Lebanon	30 patients post-coronary arterial bypass grafts Common iliac vein catheter placed at L4 level Measurements pre and post extubation	Observational cohort study	SVC pressure compared to IVC pressure		Common iliac vein rather than IVC measurement
			Before intubation	Mean difference was 0.79mmHG +/- 0.68(SD) mmHg
			After extubation	Mean difference was 0.6mmHG +/- 0.93(SD) mmHg
Walsh JT et al, 2000, UK	60 adult patients undergoing right heart studies or angioplasty 28 had impaired LV function and 38 had valvular heart disease	Observational cohort study	Difference between end expiratory right atrial pressure and SVC or IVC measurement	SVC mean difference -0.08mmHg (CI –2.2 to 0.38) IVC Mean difference -0.23mmHg (CI –1.2 to 0.58)	The variability to acute changes were not assessed Range of right atrial pressures found were not reported Inadequate recordings obtained at all recording sites for 5 patients

Comment(s)

There is extensive and consistent evidence that right atrial pressure can be reliably measured using both inferior vena cava and common iliac venous pressure measurements in supine patients. This has been proved in ventilated and spontaneously breathing adults and children. The readings of inferior vena caval measured pressures seem to be around 0.5 mm Hg lower than superior vena caval measured pressure on average and rarely more than 3 mm Hg different. This may not apply to patients with raised intra-abdominal pressure but applies to patients with high PEEP or raised mean airway pressures.

Clinical Bottom Line

Inferior vena caval or common iliac venous pressure can be used reliably to measure right atrial pressure and may be regarded as equivalent to readings of superior vena caval pressure.

References

1. Murdoch IA, Rosenthal E, Huggon IC, et al. Accuracy of central venous pressure measurements in the inferior vena cava in the ventilated child. Acta Paediatrica 1994;83(5):512-4.
2. Chait HI, Kuhn MA, Baum VC. Inferior vena caval pressure reliably predicts right atrial pressure in pediatric cardiac surgical patients. Crit Care Med 1994;22(2):219-24.
3. Yung M, Butt W. Inferior vena cava pressure as an estimate of central venous pressure. J Paediatr Child Health 1995;31(5):399-402.
4. Reda Z, Houri S, Davis AL, et al. Effect of airway pressure on inferior vena cava pressure as a measure of central venous pressure in children. J Pediatr 1995;126(6):961-5.
5. Nahum E, Dagan O, Sulkes J, et al. A comparison between continuous central venous pressure measurement from right atrium and abdominal vena cava or common iliac vein. Intensive Care Med 1996;22(6):571-4.
6. Joynt GM, Gomersall CD, Buckley TA, et al. Comparison of intrathoracic and intra-abdominal measurements of central venous pressure. Lancet 1996;347(9009):1155-7.
7. 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(3):461-4.
8. Yazigi A, Richa F, Madi S. Mesure comparee de la pression dans la veine cave inferieure abdominale et dans la veine cave superieure chez l'adulte. Ann Fr Anesth Reanim 1996;15(5):681-682.
9. Walsh JT, Hildick-Smith DJ, Newell SA, et al. Comparison of central venous and inferior vena caval pressures. Am J Cardiol 2000;85(4):518-20.