exp date isn't null, but text field is
This Guideline is applicable to all Medical and nursing staff working in neonatal units in the West of Scotland. Only a suitable trained and competent medical practitioner/ANNP should undertake arterial cannulation. Separate guidance is available for aseptic technique for procedures and for taking blood samples from an indwelling arterial catheter.
Staff should also be familiar with the use of equipment to which the arterial catheters will be connected, including: syringe driver; invasive blood pressure monitoring system; and blood sampling circuits. The use of these is covered in separate guidance
An indwelling peripheral arterial line may be used when:
Umbilical arterial lines should be sited in preference to peripheral arterial lines during the immediate newborn period unless contraindicated.
The decision to site a peripheral arterial line should be discussed with the attending neonatal consultant. The need for arterial lines should be reviewed on a daily basis on the consultant ward round.
Where time permits explain the procedure to the parents, including what the procedure involves, the reason for the procedure and the potential risks of the procedure.
Peripheral arterial catheters should be sited where there is good collateral circulation
Preferred sites:
REMEMBER: the ulnar artery may be used instead of the radial artery if access to the radial artery is problematic, but must be avoided if the radial artery has recently been cannulated (or where an attempt at cannulation has occurred). Use of the ulnar artery must be discussed with the receiving neonatal consultant and documented in the baby’s case notes.
Other sites should be avoided, except by agreement with the attending neonatal consultant.
Contraindications to peripheral arterial line insertion include:
Absolute contraindications3
Relative Contraindication
All arterial lines must be connected to a pressure monitoring system.
This allows invasive blood pressure monitoring and also provides a warning of disconnection or occlusion of the catheter.
The pressure monitor will be connected to a closed circuit blood sampling set.
The arterial pressure monitoring system and blood sampling line should be primed before use and calibrated.
Patency of the peripheral arterial line is maintained with an infusion of 0.45% sodium chloride for infusion with 1 unit of heparin per ml (known as hepsal). See WoS drug monograph for Heparin – Arterial lines. The Heparinised saline should be changed every 24 hours.
REMEMBER: No other fluids / medications are to be given via an arterial line
Choose the most appropriate artery to cannulate. If a radial artery is selected check that an ulnar artery is present and patent using Allen’s test (see below).
The Allen’s test is used to assess collateral blood flow to the hands, generally in preparation for a procedure that has the potential to disrupt blood flow in either the radial or the ulnar artery. These procedures include arterial puncture or cannulation. A negative Allen test means that the baby likely does not have an adequate dual blood supply to the hand, which will present a contraindication to the planned procedure or at least suggest that further evaluation is necessary.
Procedure:
When inserting a peripheral arterial line, a sterile procedure should be adopted in line with the applicable antisepsis guideline.
Preparation of Equipment
Prepare the following equipment on clean procedure trolley
REMEMBER: only cold light sources may be used - g. a Philips “Wee Site” or the Astodia “Diaphanoscope”
Insertion Procedure
Post-procedural care of the Cannula
Once successfully inserted, inspect the cannula site every hour and document findings on the observation chart. As these observations need to be made frequently staff should ensure that the site is easily visible and not covered with blankets or bedding.
If any concerns are identified they should be reported immediately to the medical staff
REMEMBER: Avoid inserting peripheral venous cannulae into the same hand or foot that has a peripheral arterial line in situ or that there has recently been an unsuccessful attempt at peripheral arterial cannulation until you are sure that perfusion to the limb is satisfactory.
Remove any unnecessary dressings which may impair clear viewing of the limb which contains a peripheral arterial line.
Accidental displacement of the arterial cannula will require immediate application of pressure to the site for 5-15 mins or until bleeding has stopped.
The use of a guidewire (BabyWire ®) to site or reposition a peripheral arterial line should only be used under extreme circumstances and under the guidance of a Consultant Neonatologist. A guidewire should never be used in a preterm baby less than 34 weeks gestation.
Peripheral Arterial cannula should be removed when no longer required, or if there are complications or contraindications.
Procedure:
For management of a suspected arterial occlusion or thrombosis, see separate West of Scotland guideline on management of suspected arterial occlusion or thrombosis.
Continuous arterial blood pressure monitoring will be carried out on all babies with intra-arterial lines in situ. Arterial waveform analysis provides valuable information as well as the absolute systolic and diastolic pressures. The normal wave should have a sharp peak systole upstroke and a definite end diastole.
Diagram 2. Comparison of normal, resonant and damped arterial traces.
Maintenance: Calibration
The transducer must be zeroed:
During calibration it is essential that the transducer is level with the RIGHT ATRIUM so calibration should also be checked when the child’s position is changed4.
Recording
Last reviewed: 09 October 2023
Next review: 09 October 2026
Author(s): L. Raeside – ANNP, NICU, RHC, QEUH Glasgow; Dr A MacLaren – Consultant Neonatologist, RHC, Glasgow
Approved By: WoS Neonatology MCN