Pulmonary Artery Catheters
24/11/10
FANZCA Part I Notes
USES
- continuous cardiac output monitoring
- temperature monitoring
- estimation of diastolic filling of left heart (normal PCWP 2-12mmHg)
DESCRIPTION
METHOD OF INSERTION
- like CVL insertion
- insert swan sheath @ IJ or SC
Jeremy Fernando (2011)
- SVC/RA
Pressure
Length
0-6mmHg
15-17cm
- inflate balloon with 1.5mL of air
- tricuspid valive
- RV
- pulmonary valve
diast
syst
- PA
25
0-25
35
5-15
15-30
2-10
40-50
- look for pressure waves to change
OTHER INFORMATION
Wedging
-
PA catheter tip -> small pulmonary artery (usually in RML or RLL)
phasic blood flow & pressure ceases
static column of blood between catheter tip & LA
must be in West Zone III otherwise trace will show respiratory swing.
checking in West Zone III:
->
->
->
->
->
PAWP < PADP
PAWP alters < than 50% of applied PEEP
PAWP increases by < 50% of changes in alveolar pressure
O2 saturation in wedged position greater than unwedged position (sucking back of oxygenated blood)
CXR: below level of LA
Thermal Dilution
- injection of cold fluid
- recording of change in temperature with time
- advantages: cheap, non-toxic, arterial puncture avoided, absence of re-circulation
- disadvantages: requires insertion of PAC, mixing with venous blood may be incomplete, PA
blood flow varies greatly with respiration
- causes of inaccuracies: catheter malposition, injection mistakes (volume, speed,
temperature), inaccurate thermister, TR, intra-cardiac shunts, wrong computation constant
Jeremy Fernando (2011)
Measured values
-
Q: 4-8L/min
CI: 2.5-4L/min
CVP: 2-6mmHg
PAWP: 8-12mmHg
PAP: 25/10mmHg
SvO2: 0.65-0.70
Temperature
Derived values – use of formula: Q = MAP-CVP/SVR
-
SV: 50-100mL/beat
SVI: 25-45mL/beat/m2
SVR: 900-1300 dynes-sec/cm5
SVRI: 1900-2400 dyne-sec/cm5
PVR: 40-150 dyne-sec/cm5
PVRI: 120-200 dynes-sec/cm5
Pulmonary Artery Wedge Pressure
- PAOP or PWP
= pressure within the pulmonary arterial system when catheter tip ‘wedged’ in the tapering
branch of one of the pulmonary arteries.
- in most patients this estimates LVEDP thus is an indicator of LVED volume (preload of the
left ventricle)
- normally 6-12mmHg (1-4mmHg less than the pulmonary artery diastolic pressure)
- normally measured at the end of expiration
- PCWP 18-20mmHg in the context of normal oncotic pressure -> APO likely
Jeremy Fernando (2011)
CIRCUMSTANCES WHEN PCWP > LVEDP
-
MS
atrial myxoma
pulmonary venous obstruction (fibrosis, vasculitis)
MR
non-zone III placement
L to R shunt
COPD
IPPV +/- PEEP
CIRCUMSTANCES WHEN LVEDP > PCWP
-
left ventricular failure
raised intra-thoracic pressure (high PEEP)
non-compliant LV
AR
COMPLICATIONS
Early
-
arrhythmias
heart block (6% RBBB)
infection
knotting
pulmonary infarction
hypotension
hypoxia
PA rupture
air embolism
valve damage
Late
-
thrombosis
PA rupture
sepsis
endocarditis
ARGUMENTS FOR
- in some populations (high risk cardiac surgery) helps to delineate different forms of shock.
- may facilitate the early diagnosis of shock (ie. young patients that can maintain MAP in the
face of decreasing Q).
- if IABP used can still delineate Q (unlike PiCCO)
- other monitors also have little data to support their use.
- PACMAN study showed they were safe in non-cardiac patients admitted to ICU.
ARGUMENTS AGAINST
- risk of major vessel injury with large bore introducer sheath insertion for PAFC.
Jeremy Fernando (2011)
-
risk of pulmonary artery haemorrhage.
risk of dysrrhythmia on insertion and/or high grade block if already in LBBB.
data error PAC in West Zone I.
we don’t know what an adequate Q is.
absence of data supporting an algorithm to maintain a certain cardiac output.
EVIDENCE
- RCT’s have not shown a positive effect of PAC.
- early data showed increase harm.
- PAC Man trial showed not change in in-hospital mortality.
- better to use in really sick patients.
- very invasive procedure with highly morbid complications (bleeding on insertion, PA rupture,
arrhythmia, PE).
- does change management in sick patients in the early resuscitation phase
Management of a Pulmonary Haemorrhage Post-wedging of a PAC
25/11/10
- can be a life threatening situation
Goals:
(1) prevent further pulmonary haemorrhage
(2) stop bleeding
(3) resuscitate
Call for help – anaesthetist, cardiothoracic surgeon, interventional radiology
Resuscitate
A – may have to be emergently intubated if not already
B – FiO2 1.0, controlled ventilation, if able to recognize which lung is haemorrhaging may be
able to perform lung isolation (insert single lumen tube into unaffected side or exchange for a
double lumen tube), apply PEEP
C – large bore IV cannulae, fluids, blood products, inotropes
Treatment
- stop anti-platelet and anti-coagulants
- protamine for heparin
- platelets for anti-platelet agents
- blood products as indicated by FBC, coags and clinical state
- withdraw pulmonary catheter 2-3 cm and refloat PAC with balloon inflated to occlude
pulmonary artery (to try and tamponade bleeding)
Jeremy Fernando (2011)
- angiogram or bronchoscopy to isolate pulmonary vessel involved
- if bleeding doesn’t settle will require a lobectomy
MY APPROACH TO PAC USE
-
find them useful in undifferentiated, multi-factorial shock states (for Q and ScVO2)
useful in right heart pathology and pulmonary hypertension
perform careful patient selection (including a contraindication assessment)
don’t wedge
monitor for complications (predominantly on insertion)
remove after 72 hours
Jeremy Fernando (2011)