Eur J Pediatr (1995) 154:57-59 �9 Springer-Verlag 1995

Andrze j P io t rowski Pawel Kawczynsk i

Cannulation of the axUlary artery in critically ill newborn infants

Received: 21 September 1993 Accepted: 8 June 1994

A. Piotrowski (EN) - P. Kawczynski Intensive Care Unit, Paediatric Hospital, University Shool of Medicine, ul. Sporna 36/50, PL-91-738 Lodz, Poland

A b s t r a c t The axi l lary artery has been successful ly cannula ted in criti- ca l ly ill adult and paediatr ic patients. There is li t t le informat ion about ex- per ience with this technique in neo- nates. We repor t the use of axi l lary cannulat ion in 62 mechan ica l ly ven- t i la ted neonates with bir th weight f rom 750 to 3800 g (mean 1950 g). The axi l lary artery was catheter ized with 24 or 22 gauge teflon catheters by means of the catheter-over-a- needle technique. Arter ia l access was used for b lood pressure moni tor- ing, b lood sampl ing and in seven cases for b lood remova l during ex- change transfusions. Cannulae were r emoved when the fraction o f in- spi red oxygen (FI02) was less than 0.3. Dur ing cannulat ion capi l la ry re- fill, radial artery pulse and neurolog- ical status of the arm were checked

daily. The mean per iod of cannula- t ion was 4.1 days (1 -10 days) . Dur- ing cannulat ion and after catheter re- mova l there were no compl ica t ions related to the chosen vessel e.g. no change in the skin colour, skin warmth, capi l la ry refi l l and the qual- i ty o f the radial pulse. No changes in the motor act ivi ty of the l imb on the cannula ted side were observed.

C o n c l u s i o n A x i l l a r y ar tery cannu- lat ion is a useful a l ternat ive for es- tabl ish ing an arterial access in ven- t i la ted neonates. Fur ther studies are needed to evaluate the long- te rm consequences of this technique.

K e y w o r d s Axi l l a ry artery catheter Newborn infants �9 Cri t ica l ly ill

Introduction

Arter ia l cannulat ion is an essential technique in cr i t ical ly i l l newborn infants. Umbi l i ca l arteries are most often used for this purpose, a l though their cannulat ion carries the r isk of serious compl ica t ions [3, 7] and is usual ly impos- sible in babies o lder than 1 day.

The axi l lary artery has recent ly been p roposed for arte- r ial access in paedia t r ic pat ients [1, 5, 8], after the use of this technique has been repor ted in adults [6].

F rom early 1989 we began to insert catheters percuta- neous ly into axi l lary artery in neonates. We per fo rmed a re t rospect ive rev iew to evaluate the safety o f this me thod in newborn infants.

Patients and methods

We studied all 62 neonates admitted to our Intensive Care Unit from April 1989 to June 1991 in whom we inserted catheters into the axillary artery. This vessel was chosen in infants with circula- tory compromise in whom peripheral pulses were hardly palpable and in babies with normal blood pressure after unsuccessful at- tempts to put a catheter into a peripheral artery. The technique of cannulation was similar to that described by others [2, 5]. With the patient in supine position the arm was abducted, externally rotated at 90 ~ and immobilized. The elbow was flexed, the area sterilized with iodine and axillary artery palpated in the axilla. The cannula was directed towards the artery at approximately 30 ~ to the skin and the artery punctured and cannulated directly using a catheter- over-a-needle technique. The 24 G Neoflon and 22 G Venflon catheters were used (Viggo - Spectramed, Helsingborg, Sweden) and after insertion connected to stopcocks with extension and pres-

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sure tubing (Manometer Connecting Tube, Portex, England). Arte- rial lines were continuously flushed with normal saline solution with heparin (0.5 unit/ml) at a rate of 1 ml/h. Direct arterial pres- sure display and measurement was used in all cases by means of electronic transducers and monitors (System 8000, and Medico Teknik A/S, Albertslund, Denmark).

During the period of cannulation and after catheter removal ra- dial artery pulse and capillary refill were assessed at least twice daily. Neurological status of the arm was checked daily by assess- ing reflexes and gross motor activity.

Results

In the period from April 1989 to June 1991 we catheter- ized the axillary artery on 64 separate occasions in 62 ventilated neonates. Details of the patients are presented in Table 1. The 24 G catheters were used in 44 cases and 22 G in 20 cases. The mean duration of cannulation was 4.1 days (from 1 to i0). Catheters were usually removed when babies improved and required less than 30% oxygen in inspiratory gases.

No complications related to the insertion technique (haematoma, artery or muscle spasm, pneumo- or haemo- thorax) were encountered. There was no blockage of any catheter and blood was always easily withdrawn through it from the artery. In seven cases exchange transfusions were performed with the axillary catheters as a source for blood withdrawal. The babies limbs were not immobi- lized following cannulation and there was no accidental removal of any catheter. We did not observe changes in skin warmth and colour either around the cannula or dis- tally to it. The quality of the radial pulse was well pre- served during cannulation and after removal of the catheter. No deficit in the motor function was ever de- tected in any of the limbs involved.

In two patients an inadvertent disconnection of part of the arterial line occurred, followed by a haemorrhage from the artery. This was due to the improper choice of pressure tubing without the Luer lock fittings. Blood loss was minor and did not cause problems for these patients.

Table 1 Characteristics of enrolled patients (n = 62) and duration of axillary artery cannulation

Birth weight Number Duration of cannulation [g] (mean) of patients [days] (mean)

750-1000 (920) 9 2- 6 (4.1) 1001-1500 (1310) 18 1-10 (4.0) 1501-2500 (1975) 21 2 - 7 (4.2) 2501-3800 (3020) 14 2 - 7 (3.9)

Discussion

We have demonstrated that the axillary artery can be use- ful for intra-arterial monitoring in critically ill newborn infants. There were no complications directly related to the site of cannulation. The possible complications in- clude axillary sheath haematoma with or without brachial plexus compression and a direct nerve injury [2]. Pneu- mothorax or haemothorax may occur when a needle is di- rected too deeply in a horizontal plane. The use of short cannulae and directing them at an angle not less than 30 ~ to the skin should minimize such risk.

No thrombotic complications were observed and this may be due to the large vessel-to-cannula diameter ratio [2]. The axillary artery has an extensive collateral circula- tion and even its ligation does not impair the flow of blood to the brachial artery [6], The risk of cerebral em- boli should be taken into account because of the short dis- tance to the cerebral circulation. This was observed when peripheral arterial lines were flushed too rapidly [4]. We did not use manual flushing with a syringe but increased delivery rate of heparinized saline from a syringe pump.

In our patients there was no peripheral neurological deficit after cannulation and motor function was well pre- served in all cases. The only complications were not re- lated to the chosen vessel and the introduction of Luer lock fittings to all connections prevented further discon- nections.

The advantages of axillary artery cannulation include a more accurate reflection of central systolic arterial pres- sure in comparison to a peripheral arterial catheter and easy placement of the cannula during circulatory insuffi- ciency [1]. The axillary artery may not only be used for standard purposes, but also for exchange transfusion and even extracorporeal membrane oxygenation [9]. As there is a reported incidence of prolonged compromise of blood flow after cannulation of the femoral artery [10], a similar complication with the axillary approach may be expected. A long-term follow up study is under way in our institu- tion.

Before further studies are completed, axillary artery cannulation in neonates should be reserved for situations when the use of peripheral or umbilical arteries is not pos- sible. The preductal right axillary artery should be pre- ferred and manual flushing of the arterial line avoided.

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References

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