Transcript Neonatal Intensive Care Monitoring

Neonatal Intensive Care
Monitoring
Overview
– Neonatal Blood Gases
– Pulse Oximeters
– Neonatal Hemodynamic Equipment
– Transcutaneous Monitors
Neonatal Blood Gases - Sampling
Possibilities
Arterial Gases
Venous Gases
Capillary
Arterial Gases
Radial, Brachial, Temporal Punctures
Radial Artery Line
Umbilical Artery Gases
Umbilical Artery Catheter (UAC)
Preductal placement vs postductal
placement
Venous Gases
Drawn from Umbilical Venous Catheter
(UVC)
Not desirable but......
Capillary Gases
Drawn from heel
Procedure:
– heel warmed to ‘arterialize’ blood
– lancet puncture
– blood flows, trapped in capillary tube
Preferred Sites
Variability in Cap Gases
Warming time
Amount of contact with air
Squeezing blood
As a result, not desired but .......
Comparative
pH
pCO2 HCO3 PO2
7.4
40
24
60-80
Arterial 7.4
(preterm)
40
24
50-70
Capillary 7.4
40
24
40-50
Venous
45
24
35-45
Arterial
(term)
7.35
Pulse Oximeters
Sites of attachment
(foot and hand)
Preductal placement in first twelve hours
(right hand)
Pulse Oximeters
 Reads high
– Methemoglobin
– Caboxyhemoglobin
– Jaundice
 Reads low
– Medical dyes
 Other causes of inaccuracy
– Motion
– Hypothermia/vasoconstriction
– Hypotension
– Excessive ambient light on
sensor probe
Hemodynamic Monitoring
Umbilical Artery Catheter (UAC) preferred
UAC Insertion Procedure
Insertional position 1/3 length heel to crown
Procedure
– sterile field and drape
– purse string suture around umbilicus
– cut cord and snug
– tease umbilical artery open
– insert catheter
– fix position
– follow with CXR
Monitoring UAC Post Insertion
Position of catheter tip
(aortic arch is preductal
and not preferred)
Normal position above
diaphragm
(low position is L3-L4)
Monitor leg color of
infant
(blanching indicates
obstruction of flow)
Indwelling UAC Gases
Orange Medical Company
PO2 electrode at tip of catheter
Provides continuous reading
Cathode
Anode
Transcutaneous Gas Monitors
Useful as ‘trend’ monitor
Can detect hypoxemia, hyperoxemia
Can detect hypocarbia, hypercarbia
Also responds to changes in blood flow
Types of Transcutaneous Monitors
 Single Electrode Models
PO2 most common
Types of Transcutaneous Monitors
Dual element electrodes
PO2 and PCO2
Called TcPO2 and TcPCO2
Principle of Operation
Tc Monitors
Heated electrode placed on skin
Temperature 43 to 45 C
‘Arterializes’ sample
Gas diffuses through skin
Calibration of Transcutaneous
Monitors
Requires high and low calibration
TcPO2
– Can be done with chemical zero and room air
– Most commonly done with cylinders
Calibration value = Concentration of gas in cylinder x Pb
Using a cylinder that contains 10% O2, what would be the calibration
value of a TcPO2 device if the barometric pressure was 760?
Calibration value = .1 x 760 = 76 mm Hg
Calibration of TcPCO2 Devices
Similar to TcPO2 except.......
1.6 is the factor that accounts for heating
increasing CO2 production
Calibration value = Concentration of CO2 x Pb
1 .6
Calibration value = .1 x 760 = 76 = 47.5
1 .6
1 .6
Normal Transcutaneous Gases
TcPCO2 is 35 to 45 torr
TcPO2 is 50 to 70 torr
Advantages of Transcutaneous
Monitors
Decreased number of ‘sticks’
– cost reduction
– lower infant risk (less invasive)
Trend tool
– blood sample provides ‘view’ at one moment
– gases values wander (+ 7 torr)
– infant reaction to sample varies
Problems with Transcutaneous
Monitors
Labor Intensive
– Change site every 4 to 6 hours or more
– Limited choices for attachment
– (site must have perfusion)
– Air leak around electrode
Burns
– called ‘hookies’ after Huch
Interpretation of Tc Results
Air leak under electrode
– TcPCO2 reading near zero
– TcPO2 reading near PbO2
Decreased perfusion under electrode
– TcPCO2 will increase
– TcPO2 will decrease