Neonatal Intensive Care Monitoring
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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