basic haemodynamic monitoring, CVP monitoring

1. Basic haemodynamic monitoring
Dr deepankar Mishra

2. • Blood pressure – Direct Vs Indirect
• Oxygen saturation by pulse oxymeter
• Central venous pressure
• Passive leg raising
• Venous saturation monitoring

3. Blood pressure
• Indirect methods-
by
sphygmomanoneter
• Relation between cuff (length,width)
with upper arm circumference :-
cuff L = 0.8 C
cuff W= 0.4C
C =2.5 W

5. Blood pressure
• Cuff width is most important determinant of
accuracy.
• Too narrow cuffs- overestimate BP
• Too wide cuffs- underestimate BP

6. Blood pressure- direct method
• Arterial catheter
• A flush system composed of intravenous solution,tubing
stop cocks and a flush device which provides for
continous and manual flushing of system.
• A pressure bag placed around the flush solution that is
maintained at 300 mmhg pressure ;the pressurized flush
system delivers 3-5ml of solution per hour through the
catheter to prevent clotting and backflow of blood into
the pressure monitoring system.

7. Arterial line set up

8. Invasive method...
• A tranducer to convert the pressure coming
from artery or heart chamber into an
electrical signal .Transducer should be kept at
the level of heart .
• An amplifier or moniter which increases the
size of electrical signal for display on an
oscilloscope.

9. 9
Phlebostatic Axis
• 4th intercostal space, mid-axillary line
• Level of the atria

12. PROCEDURE
• Once an arterial site is selected (radial,
femoral, or dorsalis pedis)* collateral
circulation to the area must be confirmed
before the catheter is placed. If no
collateral circulation exists and the
cannulated artery became occluded,
ischemia and infarction of the area distal to
that artery could occur.
• Collateral circulation to the hand can be
checked by the Allen test

13. Normal waveforms

15. Arterial line dynamic response testing
• Dynamic Response is a function of Natural
Resonant Frequency and Damping Coefficient
• The Natural Resonant Frequency: How fast
the system vibrates in response to a pressure
signal
• The Damping coefficient: How quickly those
vibrations come to rest in the system

16. Square wave test

17. Overdamped arterial waveforms

18. Underdamped arterial waveforms

19. • Underdamping – results in excessive
resonance in the system leading to
overestimate of systolic pressure and an
underestimate of diastolic pressure.
• Overdamping – reverse
• In both these condition mean arterial pressure
is most accurate .

20. Return-to-Flow Technique

21. COMPLICATIONS
• Local destruction with distal ischemia
• external hemorrhage
• massive ecchymosis
• dissection
• air embolism
• blood loss
• pain
• arteriospasm and
• infection.

22. CENTRAL VENOUS PRESSURE
MONITORING
The CVP, the pressure in the vena cava or
right atrium, is used to assess right ventricular
function and venous blood return to the right
side of the heart. The CVP can be continuously
measured by connecting either a catheter
positioned in the vena cava or the proximal
port of a pulmonary artery catheter to a
pressure monitoring system

23. COMMON CENTRAL LINE INSERTION
SITES
• Right internal jugular
• left internal jugular
• right subclavian
• left subclavian
• femoral (as a last resort)
• Or peripherally inserted
central catheters (PICC)
which are inserted via
the antecubital veins
(basilic vein is the best)
in the arm and is
advanced into the
central veins

24. PROCEDURE
• Before insertion of a CVP catheter, the site is
prepared by shaving if necessary and by
cleansing with an antiseptic solution.
• A local anesthetic may be used. The physician
threads a single lumen or multilumen catheter
through the internal jugular, subclavian or
femoral vein.

26. CVP
• Once the CVP catheter is inserted, it is secured and a
dry, sterile dressing is applied.
• Catheter placement is confirmed by a chest x-ray, and
the site is inspected daily for signs of infection. The
dressing and pressure monitoring system or water
manometer are changed according to hospital policy.
• In general, the dressing is to be kept dry and air
occlusive.
• Dressing changes are performed with the use of sterile
technique.

27. • CVP catheters can be used for infusing
intravenous fluids, administering
intravenous medications, and drawing
blood specimens in addition to monitoring
pressure.
• To measure the CVP, the transducer (when
a pressure monitoring system is used) or
the zero mark on the manometer (when a
water manometer is used) must be placed
at a standard reference point, called the
phlebostatic axis .

28. THE CVP WAVEFORM
• The CVP waveform reflects changes in right
atrial pressure during the cardiac cycle

29. EDV vs EDP

30. Central venous pressure Vs Central venous volume

31. • As a rule of thumb-
if difference between CVP before and 5 mins
after fluid bolus is 0-3 mmhg, the patient is
underfilled .
if it is 3-5 mmhg – adequately filled ,
if it is >5 mmhg - overfilled

32. Complications of CVP line
• Pneumothorax
• Haemothorax
• Chylothorax
• Damage to major vessel
• Catheter /guidewire embolisation
• Cardiac arrhythmia
• Haemorrhage

33. Rise in pulse pressure >10% indicates
hypovolemia
• Passive leg raising

34. Venous saturation monitoring
• If tissue blood flow is inadequate – more
extraction of O2 from blood by tissues
leads to fall in O2 saturation in venous blood .
• Can be monitored continuously by fibre optic
catheter or intermittently by sampling from
CVP .
• In severe septic shock – goals to achieve
central venous sat >70%