2. HEMODYNAMIC MONITORING
What are we really worried about?
“Tissue Hypoperfusion”
What do we really want to monitor?
“Adequate Oxygen Delivery”
Definition of Shock:
“Inadequate tissue perfusion affecting multiple
organ systems.”
7. IS PATIENT VOLUME RESPONSIVE?
Primary resuscitation question is whether the
patient will increase their cardiac output in
response to intravascular volume infusion.
That is why almost always the first step is to give
fluids and see patient’s response, in case of a
hypotension.
It is important to determine “ volume
responsiveness” !!!
9. HOW TO ASSES VOLUME RESPONSIVENESS?
Volume Responsiveness was defined as increase
in CO by 15% or more, by 500 ml fluid bolus.
Passive Leg Raising*
CVP vs. EDV/EDVI?
New Generation Monitors
Stroke Volume Variations
Pulse Pressure Variations
Systolic Pressure Variations
10. CENTRAL VENOUS PRESSURE
CVP =Preload?
CVP can reflect a volume increase in RA pressures or
decrease in RV contractility
can be both.
Need to be monitored in conjunction with other
monitors.(CVP&MAP)
The main limitations of CVP monitoring:
(a) it does not allow to measure cardiac output
(b) it does not provide reliable information on the status of
the pulmonary circulation in the presence of left ventricular
dysfunction.
12. “An isolated CVP reading is of
limited value; a trend of readings
is much more significant and
should be viewed in conjuncton
with other parameters e.g. BP
and urine output.”
14. Thermodilution ( TD):
Dilution of Temperature (Cold NS)
Area Under the Curve (AUC)
Pulmonary Artery Catheter ( PACs) or
Newer Generation CVL w sensors
Intermittent vs. Continuous TD
Dye/Indicator Dilution:
Same Technique ( Dilution of dye or indicator instead
of NS) Dye(indocyanine green) vs. Indicator(
Lithium) A line vs. CVL , no need for PACs.
MEASUREMENT OF CARDIAC OUTPUT
19. SVV – FLOWTRAC
Can be used as a tool for volume responsiveness in
low CO states.
SVV > 13% = Volume Responsive
“SVV and PPV are more effective indicators for
Volume Responsiveness then static indicators of
preload (CVP, PAOP).”
Limitations:
Pt needs to be on 100% Controlled Mechanical
Ventilation.
Spontaneous Ventilation & SVV ?
Arrhythmias can affect SVV.
20.
21. HOW DO WE MEASURE SVO2% & SCVO2% ?:
Swan Ganz Pulmonary Artery Catheter:
“Old Method, New Technology”
Advanced Technology Catheters:
Swan-Ganz CCOmbo Pulmonary Artery Catheter:
(Combo = Continuous CO + Venous Oximetry)
Swan-Ganz CCOmbo VIP Catheters:
CCO &Venous Oximetry
Provide additional lumen.
23. CENTRAL VENOUS PRESSURE
MONITORING
Introduction
Indications and Contraindications
Instrument-Central venous catheter types
Procedure-Access to Different Great Vessels
Advantage and disadvantage of different routes
Complications and its Rx
24. INTRODUCTION
Central venous access is defined as placement of a
catheter such that the catheter is inserted into a
venous great vessel.
The venous great vessels include the superior vena
cava, inferior vena cava, brachiocephalic veins,
internal jugular veins, subclavian veins, iliac veins,
and common femoral veins.
25. INDICATIONS
1. Central Venous Pressure
Monitoring
The central venous pressure
(CVP) is the pressure
measured in the large central
veins close to Right atrium.
It indicates mean right atrial
pressure and is frequently
used as an estimate of right
ventricular preload.
26. 2. Introduction of transvenous cardiac Pacemakers or
Pulmonary Artery Catheters(for more comprehensive
cardiac monitoring)
3.For haemodialysis/haemofiltration –
For acute and chronic haemodialysis.
INDICATIONS
27. 4. Provision of Caustic Medications or Solutions
Vasoactive medications (vasopressors or inotropes)
Irritant substances (chemotherapeutic agents,
cytotoxic drugs or high concentration solutions)
Total parenteral nutrition
INDICATIONS
28. 5. Inadequate peripheral venous access eg- burns,
hypovolemic shock.
6. Rapid infusion of fluids(via large cannulas)
Eg-trauma,major surgery
7 .Aspiration of air emboli(during posterior
craniotomies)
8.Repeated blood sampling
30. CONTRAINDICATIONS
Relative
Bleeding disorders & anticoagulation or thrombolytic
therapy.
3% complication rate as long as there are no arterial
punctures
Absolute contraindication for subclavian access
Ultrasound guidance is recommended
31. TYPES OF CENTRAL VENOUS CATHETERS
1. Non-tunneled central
catheters
2. Tunneled central
catheters(hickmans
catheters)
3. Peripherally inserted
central catheters (PICC)
4. Implantable ports
32. TYPES OF CENTRAL VENOUS CATHETERS
Single & multi-lumen catheters are available in
all catheter types
Each lumen must be treated as a separate
catheter
33. Open–ended
The catheter is open at the distal tip
The catheter requires clamping before entry into
the system
Clamps are usually built into the catheter
Requires periodic flushing
TYPES OF CENTRAL VENOUS CATHETERS
34. TYPES OF CENTRAL VENOUS CATHETERS
Closed-ended
A valve is present at the tip of the catheter (eg.
Groshong®) or at the hub of the catheter(eg.
PAS-V®)
Clamping is not required as the valve is closed
except during infusion or aspiration
35. TYPES OF CENTRAL VENOUS CATHETERS
Composition
Silicone
Polyurethane
Pvc
Teflon
Coatings
Antimicrobial or
antiseptic coating
Heparin coating
Radiopaque to
confirm tip
placement
38. TECHNIQUES OF CENTRAL VENOUS
CANNULATION:
1. Catheter over the needle
Longer version of a conventional intravenous
cannula.
Catheter is larger than needle ► reduces the
leakage of blood from the insertion site.
Accidental arterial puncture can occur due to
larger needle.
Over insertion can damage the vein.
39. TECHNIQUES CONTD…
2. Catheter over guidewire ( Seldinger technique)
Preferred method of insertion.
18-20 G, small diameter needle is used.
A guide wire passed down the needle in to the vein
and needle removed.
Guidewire commonly has flexible J shaped tip
1. Reduces the risk of vessel perforation.
2. Helps negotiate valves in vein.
Once the wire is placed in the vein catheter is
passed over it.
40. SELDINGER TECHNIQUE
Location of the Vein with a finder Needle [Optional]
Placing the Introducer Needle in the Vein(
Assessment for Venous or Arterial Placement)
Insertion of the Guide Wire through the needle
Removal of the Introducer Needle
Skin Incision
Insertion of the Dilator
Placement of the Catheter over the guidewire
Removal of the Guide Wire
Flushing and Capping of the Lumens
Secure the Catheter in situ
41. SELDINGER TECHNIQUE
Use introducing needle
to locate vein
Wire is threaded
through the needle
Needle is removed
Skin and vessel are
dilated
Catheter is placed over
the wire
Wire is removed
Catheter is secured in
place
42. 3. Catheter through the needle or through
cannula
Catheter passed through a cannula or needle
placed in the vein.
Hole made in the vein by the needle larger than
the catheter ► some degree of blood
leakage around the site.
Withdrawal of catheter through needle risks
shearing off catheter
▼
Catheter embolisation
TECHNIQUES CONTD…
43. TUNNELLED CATHETERS
Single or multiple lumens
Used for long term therapy
Inserted surgically
Small Dacron (Polyethylene terephthalate) cuff sits in
subcutaneous tunnel facilitates anchoring of the
catheter through granulation and acts as a barrier to
infection
44. ADVANTAGES DISADVANTAGES
Can be left in place
indefinitely (if no
infection, blockage or
thrombosis)
Self-care by patient
External portion can
be repaired
Inserted in the OR
Requires a dressing &
frequent assessments
External device
Physician must
remove
45. PERIPHERALLY INSERTED CENTRAL CATHETERS
Silicone or polyurethane
Single or multi-lumen
Approximately 40-60 cm long
Used for intermediate to long term
therapy
Inserted percutaneously
Basalic vein
Cephalic vein
The tip rests in the superior vena
cava at the cavo-atrial junction.
46. ADVANTAGES DISADVANTAGES
Can remain in place
for several weeks to a
year
Can be easily removed
Low infection rates
External portion can
be repaired
Low flows
Requires a dressing &
frequent assessments
External device
Small gauge PICC not
recommended for
blood sampling
47. ACCESS TO DIFFERENT GREAT VESSELS
Internal jugular vein
Subclavian vein
Femoral vein
Umbilical vein
48. INTERNAL JUGULAR APPROACH
Positioning
Right side preferred. patient placed supine
Tredlenburg position 15 – 30 degrees
Head turned slightly away from side of venipuncture
Needle placement: Central approach
Locate the triangle formed by the clavicle and the
sternal and clavicular heads of the SCM muscle
palpate carotid artery with left hand fingers within
it.
Place needle at 30 to 40 degrees to the skin,at the
apex of the triangle, lateral to the carotid artery
Aim toward the ipsilateral nipple under the medial
border of the lateral head of the SCM muscle
Vein should be 1-1.5 cm deep
50. SUBCLAVIAN APPROACH
Positioning
Right side preferred
Supine position, head neutral, arm abducted
Trendelenburg (10-15 degrees)
Shoulders neutral with mild retracted
Needle placement
Junction of middle and medial thirds of clavicle
At the small tubercle in the medial deltopectoral
groove
Needle should be parallel to skin
Aim towards the supraclavicular notch and just
under the clavicle
52. FEMORAL APPROACH
Positioning
Supine
Needle placement
Medial to femoral artery
Needle held at 45 degree angle
Skin insertion 2 cm below inguinal ligament
Aim toward umbilicus
53. POST-CATHETER PLACEMENT
Aspirate blood from each port
Flush with saline or sterile water
Secure catheter with sutures
Cover with sterile dressing (tega-derm)
Obtain chest x-ray for IJ and SC lines
Write a procedure note
54. TIPS
After 3-4 tries, let someone else try
Get chest x-ray after unsuccessful attempt
If attempt at one site fails, try new site on same
side to avoid bilateral complications
Halt positive pressure ventilation as the needle
penetrates the chest wall in subclavian approach
If you meet resistance while inserting the guide
wire, withdraw slightly and rotate the wire and re-
advance
Use the vein on the same side as the pneumothorax
Withdraw slowly, you will often hit the vein on the
way out
55. ULTRASOUND-GUIDED CENTRAL VENOUS
ACCESS
Become standard of care
Vein is compressible
Vein is not always larger
Vein is accessed under direct
visualization
Helpful in patients with
difficult anatomy
58. Location Advantage Disadvantage
Internal
Jugular
• Bleeding can be recognized
and controlled
• Malposition is rare
• Less risk of pneumothorax
• Risk of carotid artery puncture
Femoral • Easy to find vein
• No risk of pneumothorax
• Preferred site for
emergencies and CPR
• Highest risk of infection
• Risk of DVT
• Not good for ambulatory
patients
Subclavian • Most comfortable for
conscious patients
• Highest risk of PTX,
• Should not be done if < 2 years
• Vein is non-compressible
59. CATHETER TIP LOCATION
Ideal catheter tip location is
within SVC 3to 5 cm proximal to cavo-atrial
junction, parallel to vessel wall.
Below the level of inferior border of clavicle
Above the level of 3rd rib, t4-5 interspace,tracheal
carina(reliable radiological landmark) or the
takeoff of the rt tracheobronchial angle.
62. ACUTE COMPLICATIONS
Cardiac Dysrhythmias
Due to cardiac irritation by the wire or catheter tip.
Withdraw the line into the superior vena cava.
Always use a cardiac monitor.
Haematoma formation – Arterial/Venous puncture
Mechanical injury to nearby structures
Pneumothorax/Haemothoarx
Atrial wall puncture - pericardial tamponade.
Bowel penetration, Bladder puncture, Femoral nerve injury
Air embolus
Malposition
Lost Guide-wire
63. CHRONIC COMPLICATIONS
Infections – CLA-BSI,
Catheter fragmentation
Non-function/Blockage - fibrin builds on and
around the catheter and vessel, drug precipitates,
lipid deposits
Thrombosis/Thromboembolism
64. INFECTIONS
Most frequent and serious complications.
Types
Local infection – Cellulitis
Central Line-Associated Bloodstream Infections
(CLABSI)
65. Causative Organisms
Staph epidermidis 25-50%
Staph aureus 25%
Candida 5-10%
Risk Factors
Cutaneous colonization of the insertion site
Moisture under the dressing
Prolonged catheter time
Technique of care and placement of the central line
INFECTIONS
66. EVIDENCE-BASED STRATEGIES SELECTED
TO REDUCE CLA-BSIS
1. Hand hygiene
2. Maximal sterile barriers
3. Chlorhexidine for skin asepsis
4. Avoid femoral lines
5. Avoid/remove unnecessary lines
67. CVP MEASUREMENT
Definition
The Central Venous Pressure (CVP) or the Right Atrial
Pressure (RAP) - is the pressure measured at the tip of a
catheter placed within a central vein or the Right Atrium
(RA).
Purpose:
• To assess patient’s fluid volume status.
• To assess preload of the heart
• Provide information about the Right Ventricular
function and
allows for evaluation of right-sided heart
hemodynamics and
evaluation of patient response to therapy.
68. CVP – CENTRAL VENOUS PRESSURE
Cvp is the pressure measured usually at junction
of SVC and rt atria and it reflects the driving
force for filling the rt atria and ventricle.
Cvp depends on –
intravascular blood volume
intrinsic venous tone of capacitance vessels,
compliance of heart
intrathoracic pressure
Myocardial compliance
69. TEMPORAL RELATION B/W CVP WAVEFORM
AND ECG TRACE
a=atrial contraction.
c=sudden motion of the AV ring
toward the right atrium
x descent=atrial relaxation
v=pressure generated by venous
filling
of the right atrium
y descent=rapid emptying of the
RA into RV
70. METHODS FOR MEASURING CVP
• Water Manometer Flush System – provide only a
numerical value and measure centimeters of water
pressure (cm of H2O).
• Hemodynamic Monitoring/Mercury Transducer
System
- allow for analysis of the waveform and measurement
of the pressure by mm Hg pressure.
Formula for conversion: cm H2O÷1.36 = mm Hg
Normal CVP value: 2 to 7 mm Hg = 3 to 10 cm
H2O
73. PURPOSE
The primary purpose of invasivehemodynamic
monitoring is the early detection, identification,
and treatment of life-threatening conditions such
as Heart failure and cardiac tamponade, which
non invasive methods take longer time to detect
or fail to detect.
To evaluate the patient's immediate response to
treatment such as drugs and mechanical support.
To evaluate the effectiveness of cardiovascular
function such as cardiac output, and cardiac
index.
75. SOME HISTORY…
First pulm catheters were placed in 1940s
1970-William Ganz and Harold Swan introduced this
catheter. Pulmonary artery Catheter that is balloon-tipped
and flow directed, placed bedside
76. BASIC CATHETER FEATURES
Made of polyvinylchloride (thrombogenic)
Has a pliable shaft that softens at body
temperature( heparin bonding reduces risk of
thrombogenesis)
110 cm in length, marked at 10 cm intervals
external diameter vary from 7 to 9 French (1
French=0.0335mm)
A Balloon is fastened 1-2mm from the tip and
when inflated it guides the catheter (using fluid
dynamic drag) from greater intrathoracic veins
through right heart into pulmonary artery
77. BASIC CATHETER FEATURES
PAC are available in wide varieties
1. Double lumen-one lumen to inflate the balloon and
other to measure PAP/blood sampling
2. Triple lumen- and additional lumen to measure RAP
3. Quadruple lumen-which has a 4th lumen which
houses wires for the temp thermistor-used to
measure C O
4. Five lumen- can be used for pacing/ drug infusion./02
saturation(fibre optics probe)
78. TYPICALLY A PAC CATHETERS HAVE 4
PORTS/LUMENS
1. White port with blue wire is the proximal port-
terminates at 30cm from tip of catheter and is
used to measure right atrium pressures
2. White port, yellow wire is the PAD distal port
3. White port with red wire is for balloon inflation
4. Last port has the connection to the
thermodilution cardiac output computer-
contains the electrical leads for thermistor.
79.
80.
81.
82. USES OF PULMONARY ARTERY CATHETER
Assessment of volume status in patients
undergoing major surgeries
Cardiac output measurement
Various hemodynamic parameters-
pulmonary artery pressure, pulmonary
capillary wedge presssure, CVP,systemic
vascular resistance, pulmonary vascular
resistance.
Respiratory or oxygen transport
measurement-mixed venous oximetry.
83. PULMONARY ARTERY CATHETERISATION
AND OUTCOME CONTROVERSIES
PAC use in 5735 patients in first 24 hrs intensive care
associated with increased mortality, hospital stay and
cost.(Connors etal,1997)
Three trials including 3468 patients showed no effect on
mortality but higher incidence of adverse effects(Harvey
etal,2005; The ESCAPE Trial,2005; Sandham etal,2003)
A review of 53312 patients from National Trauma Data
Bank showed
-No mortality benefit in patients treated with PAC
-Injury scale greater: mortality decreased(Friese etal,2006)
In mixed medical and surgical population,APACHE scores
<25 -increased mortality
>31 -significant benefit (Chittock etal,2004)
84.
85.
86. RECOMMENDATIONS FOR PERIOPERATIVE
USE OF PACS(AHA 2007 GUIDELINES)
Class 2b-(level of evidence:B)
Use of PAC is reasonable in patients at risk for major
hemodynamic disturbances easily detected by PAC.
However, decision must be based on three parameters-
a. disease (patient s condition)
b. surgical procedure
c. practice setting (Experience & interpretation)
Class 3-(level of evidence:A)
Routine use of PAC perioperatively, especially low
risk of hemodynamic disturbances, is not
recommended.
87. 1. Patients undergoing cardiac surgery with
Poor left ventricular compliance(ejection fration
<0.4, LVEDP>18mm hg)
Left wall motion abnormality
Recent MI (<6 Months)
Left main coronary lesion
Valvular lesion
Presence of pulmonary artery hypertension
INDICATIONS
88. INDICATIONS
2. Major procedures involving large fluid
shifts or blood loss in patients with-
Cardiogenic or septic shock or with multiple
organ failure
Hemodynamic instability requiring ionotropes
or intra-aortic balloon counterpulsation
Hepatic transplantation
Massive ascites requiring major surgery
Surgery of aorta requiring cross-clamping
Large abdomino-perineal resection etc.
89. 3. Intensive care unit
To measure pulmonary artery and pulmonary
capillary wedge
pressure
To measure cardiac output by thermodilution
To obtain intracavitary electrocardiogram
To perform atrial or ventricular pacing
To allow infusion of drugs
To perform angiography
To detect venous air embolism
4. Continous mixed venous oximetry
- To assess the adequacy of perfusion
INDICATIONS
91. INSERTION
Sites of insertion –pac can be inserted from
any of central venous cannulation sites.
Right internal jugular vein (preferred)
Left internal jugular vein (2nd choice)
Subclavian vein (disadvantages)
External jugular vein ( superficial location but
tortous)
Antecubital vein
Femoral vein
92. INSERTION TECHNIQUES
Average time from decision to use PA catheter
until onset of catheter based treatment is 120
minutes
Goal: get the catheter to the pulmonary artery
Cordis into right internal jugular vein or left
subclavian allows easiest passage
Swan should be oriented ex-vivo to approximate
the course in the body
93.
94. INSERTION TECHNIQUES
Catheter goes through an introducer and into the
vein. The balloon stays closed until it reachs the
right atrium.
When it reachs the right atrium (20cm), balloon
inflated to reduce possibility of injury to the
myocardium.
Then the balloon moved quickly through the
right ventricle (30cm) and then pulmonary artery
(40cm) and PCWP (50cm) from suclavian/ IJV
approach
95. WAVE FORM RECORDED DURING PASSAGE OF PAC
• Right atrial pressure resembles central venous pressure
waveform
• Right ventricular pressure shows higher systolic pressure
• Pulmonary artery pressure shows diastolic step up
• Pulmonary artery wedge pressure similar morphology as right
atrial pressure but a,c, v waves appear later
96.
97.
98. RA RV PA
IJV-right 20cm 30cm 45cm
left 25cm 35cm 50cm
Antecubital –rt 50cm 65cm 80cm
-lt 55cm 70cm 85cm
Femoral v 40cm 50cm 65cm
Subclavian v 10cm 25cm 40cm
Distances to right atrium, right ventricle and pulmonary artery
99.
100. INFORMATION GIVEN BY THE “SWAN”
Pulmonary Artery (PA) Pressure
Central Venous Pressure (CVP) Pressure
Pulmonary Capillary Wedge Pressure (PCWP or
“Wedge”)
Cardiac Output (in Liters/minute)
SVO2
Systemic Vascular Resistance
Pulmonary Vascular Resistance
Cardiac Index
101. INFORMATION GIVEN BY THE “SWAN”
This data can be subdivided into the following
areas:
Continuously Monitored
Intermittently Monitored
Derived by calculations
Continuously Monitored Parameters:
Pulmonary Artery Pressure (PA)
Central Venous Pressure (CVP)
SvO2
103. ALSO CONTINUOUSLY MONITORED….
Although optional
SvO2
Saturation of Venous Oxygen
Measured in the Pulmonary Artery
This reading is the Only TRUE mixed
venous.
104. INTERMITTENTLY MONITORED
1. Pulmonary Capillary Wedge pressure (PCWP)
Balloon is inflated, a pressure reading is taken, the
balloon is deflated. Leaving the balloon inflated will
produce INFARCT of the lung!
2.Cardiac output-
--thermodilution method
105.
106. INTERMITTENTLY MONITORED
CARDIAC OUTPUT BY “THERMO DILUTION”
•Cold fluid is injected into the “Injectate port”
of the catheter. The temperature of the fluid is
measured at two points by the thermistor on
the catheter and calculated to cardiac output.
107. CALCULATIONS
Systemic Vascular Resistance -SVR
How hard is it get blood through the vascular
system?
Pulmonary Vascular Resistance -PVR
How hard does the right heart have to work to get
blood through the lungs and back to the left heart?
Cardiac Index
These calculations are subject
to error!
111. INDICATIONS
1.when beat-to-beat blood pressure changes are
anticipated and rapid detection is vital
these conditions include-
Patients with PRE EXISITING SEVERE CVD
(recent MI,
unstable angina,
severe CAD
severe valvular disease
CHF/RHF
, pulmonary HTN/embolism/COPD)
HEMODYNAMICALLY UNSTABLE PTS
(shock-hypovolemic/cardiogenic,/septic,/mof)
(-iCU pts requiring inotropic support )
112. When PLANNED SX may cause sudden CV
changes
( cardiopulmonary bypass
sx on a major vessel eg- aorta
delibrate hypotension
delibrate hypothermia)
SX involving rapid blood loss/ large fluid
shifts(massive trauma cases)
2.Frequent arterial blood gas analysis
-pts with respiratory failure on ventilator
-severe acid/base disturbance.
INDICATIONS
113. 3.failure of NIBP
eg- in profoundly hypotensive patients, in non
pulsatile cardiopulmonary bypass,in morbidly
obese patients.
4.Supplementary diagnostic information
from arterial waveform
eg- identification of dicrotic notch serves as
timing for intra aortic balloon counter pulsation.
5.Determination of volume responsiveness
from SBP/PP variation
INDICATIONS
114. CHOICE OF ARTERIAL SITE
Location of sx
Possible compromise of arterial flow due to
patient positioning or sx manipulation
h/o ischemia or previous sx on the limb to be
cannulated
h/o proximal arterial cut down(produces
dampened waveform/falsely low bp due to
stenosis or vascular thrombosis)
115. CHOICE OF ARTERIAL SITE
The radial artery has low complication
rates compared with other sites.
It is a superficial artery which aids insertion,
and also makes it compressible for haemostasis
The ulnar, brachial, axillary, dorsalis
pedis, posterial tibial, femoral arteries are
alternatives.
116. PREPARATION- ALLEN’S TEST
The idea here is to figure out
if the ulnar artery will supply
the hand with enough blood,
if the radial artery is blocked
with an a-line.
Allen’s test is recommended before the
insertion of a radial arterial line.
This is used to determine collateral circulation
between the ulnar and radial arteries to the
hand If ulnar perfusion is poor and a
cannula occludes the radial artery, blood
flow to the hand may be reduced.
The test is performed by asking the patient to
clench their hand. The ulnar and radial arteries
are occluded with digital pressure.
The hand is unclenched and pressure over the
ulnar artery is released. If there is good
collateral perfusion, the palm should flush in
less than 6 seconds.
118. EQUIPMENT
Arterial cannula
Made from polytetrafluoroethylene (‘Teflon’) to
minimize the risk of clot formation
20G (pink) cannula - adult patients
22G (blue)- paediatrics
24G (yellow) - neonates and small babies
Larger gauge cannulae increase the risk of
thrombosis,
smaller cannulae cause damping of the signal.
The cannula is connected to an arterial tubing set.
119. Arterial set.
- Specialized plastic tubing, short and stiff to reduce
resonance, connected to a 500 ml bag of saline.
Saline bag
-500 ml 0.9% saline pressurized to 300 mmHg using a
pressure bag.
-The arterial set and pressurized saline bag with
2500units Heparin incorporate a continuous slow flushing
system of 3–4 ml per hour to keep the line free from clots.
-The arterial set and arterial line should be free from air
bubbles.
- The line is attached to a transducer.
120. Do not allow the saline bag to empty
–To maintain patency of arterial cannula.
–To prevent air embolism
–To maintain accuracy of blood pressure reading
–To maintain accuracy of fluid balance chart
–To prevent backflow of blood
Transducer, amplifier and electrical recording
equipment.
The transducer is zeroed and placed level with
the heart.
121.
122. PROCEDURE
1.take consent,
2. Assure that pressure tubing with transducer
is connected to bedside monitor.
3. For the radial artery, the arm is restrained,
palm up, with an armboard to hold the wrist
dorsiflexed
123. PROCEDURE
Course of artery identified(proximal to wrist in
case of radial artery) by palpation
Skin is prepared with antiseptic,
LA injected i.d and s.c along side of the artery.
Arterial catheterization done with std iv
catheter/integrated guidewire-catheter assembly
designed for this purpose.
Initially needle is directed at 30 – 45 degree
angle to skin. Once arterial back flow is seen in
flash chamber catheter is advanced 1-2mm into
the lumen of vessel.
monitoring system pressure tubing fastened to
the catheter.
124. POSITIONING
For the radial artery, the most common insertion, the arm is
restrained, palm up, with an armboard to hold the wrist
dorsiflexed
126. HOW IT WORKS ???
A transducer is a device that reads the
fluctuations in pressure – it doesn’t matter if it’s
arterial, or central venous, or PA
The column of saline in the arterial set transmits the
pressure changes to the diaphragm in the transducer
The transducer reads the changing pressure, and
changes it into an electrical signal that goes up and
down as the pressure does which is displayed as an
arterial waveform
128. TRANSDUCER - A COUPLE OF THINGS TO
REMEMBER
The transducer has to sit in a “transducer holder”
The transducer has to be levelled correctly-to make
sure that it’s at the fourth intercostal space, at the
mid-axillary line (Phlebostatic axis)
Make sure there’s no air in the line use the flusher
to clear bubbles out of the tubing.
Zero the line to atmospheric pressure properly
129. TYPICAL ARTERIAL WAVEFORM
The upstroke measures
the systolic pressure
Downfall represents
diastolic pressure
The highest point - peak
systolic pressure,
-the lowest is the end
diastolic
130. The difference b/w the two represents SV
A small dip in the downstroke represents
“dicrotic notch”.,created byaortic valve closure.
There are 2 main abnormal tracing problems that
can occur once the monitor gain is set correctly.
1.dampened trace
2.resonant trace.
131. DAMPENED: WIDE, FLATTENED TRACING
Dampening occurs due to:
air bubbles
clots
overly compliant, distensible tubing
catheter kinks
low flush bag pressure or no fluid in
the flush bag
Improper scaling
Severe hypotension if everything
else is ruled out
Under estimate SBP, over estimate DBP
132. RESONANT: ‘SPIKED’ TRACING
Resonance occurs due to:
long tubing
overly stiff, non-compliant tubing
increased vascular resistance
reverberations in tubing causing
harmonics that distort the trace
(i.e. high systolic and low diastolic)
non-fully opened stopcock valve
Over estimates SBP, under estimate
DBP
133. COMPARISON WITH NON-
INVASIVE BP
Arterial lines measure systolic BP
approximately 5 mmHg higher and the
diastolic BP approximately 8 mmHg lower
compared to non-invasive BP (NIBP)
measurement
134. COMPLICATIONS
Haemorrhage may occur if there are leaks in the
system.
Emboli. Air or thrombo emboli may occur.
Accidental drug injection may cause severe,
irreversible damage to the hand.
-No drugs should be injected via an
arterial line
- The line should be labelled (in red) to reduce the
likelihood of this occurring
Arterial vasospasm
135. Partial occlusion due to large cannula width, multiple
attempts at insertion and long duration of use
Permanent total occlusion
Sepsis or bacteraemia secondary to infected radial
arterial lines is very rare (0.13%)
-local infection is more common.
Skin necrosis, severe gangrene, limb ischemia,
amputation & permanent disabilities
COMPLICATIONS