Ipsilateral placement of central venous catheters and dialysis catheters does not affect the distance between line tips,blood pressure or noradrenaline requirements

Abstract

Debate exists about the safety of inserting central venous catheters (CVC) and central venous dialysis catheters (CVDC) ipsilaterally, lest the catheter tips lie in close proximity risking direct aspiration of vasopressors from the CVC into the CVDC. This study showed that ipsilateral or contralateral placement did not affect the distance between CVC and CVDC line tips. There were no significant adverse changes in cardiovascular parameters or noradrenaline dose when CRRT was commenced regardless of whether the lines were inserted ipsilaterally or contralaterally.

Introduction

Critically ill patients may simultaneously require vasoactive drugs delivered by a central venous catheter (CVC) and continuous renal replacement therapy (CRRT) via a central venous dialysis catheter (CVDC).

Experimental and animal models have demonstrated direct aspiration from closely located line tips, risking removal via the haemofilter prior to circulation around the body.^{1 –4} Animal studies have shown a significant increase in noradrenaline requirements when CVC and CVDC are located within the same vein.^4,5

It is unclear whether siting CVDCs and CVCs via contralateral veins reduces this risk. However, one study found contralateral placement did not influence the distance between the tips of the CVC and CVDC. ⁶

Aims

We aimed to explore whether the insertion site (contralateral or ipsilateral) of lines affected the distance between line tips. We also assessed whether initiation of CRRT was associated with hypotension or increased noradrenaline requirement and, if so, whether this related to ipsilateral or contralateral line placement.

Methods

This retrospective observational study was performed in the intensive care units of two UK district general hospitals. Consecutive cases of patients who had both a CVC and CVDC in either internal jugular or subclavian veins and were started on CRRT (mode: continuous veno-venous haemodiafiltration), while receiving a noradrenaline infusion. Patients were grouped into those with lines sited on the same side (ipsilateral group) and those on opposite sides (contralateral group). Post-line insertion chest X-rays were reviewed (PACS: SECTRA UniView). The most recent heart rate, mean arterial pressure (MAP) and noradrenaline requirements from before and after the initiation of CRRT were compared. Data was sourced from ICCA Philips patient data management system. Observations and infusion rates routinely updated hourly. Statistical analysis was performed using R version 4.4.2 (R Foundation for Statistical Computing, Vienna, Austria). Normality of data was tested using the Shapiro-Wilk test, with normally distributed data presented using mean ± standard deviation (SD) and non-normal data presented using median (interquartile range; IQR). Student’s t-test or exact Wilcoxon test were used to compare between groups and multivariate linear regression to determine the effect of variables on changes in noradrenaline requirements post-CRRT.

Results

The analysis included 57 episodes in 50 patients (64% male, mean age 60); (2020–2023). 36 line placements were contralateral and 21 ipsilateral.

Distance between line tips was not significantly different: ipsilateral group; 3.1 (1.5–4.3) cm and contralateral group; 2.9 (1.7–4.6) cm (p = 0.92).

The ipsilateral group’s MAP was 72.7 ± 11.3 mmHg pre-CRRT and 74.4 ± 12.9 mmHg post-CRRT (p = 0.53). The contralateral group’s MAP was 71.2 ± 8.5 mmHg pre-CRRT and 71.1 ± 10.0 mmHg post-CRRT (p = 0.72).

The mean heart rate in the ipsilateral group prior to CRRT was 87 (SD 23.4) bpm and 85 (SD 20.3) bpm after (p = 0.12). In the contralateral group prior to CRRT mean heart rate was 101 (SD 24.4) bpm and 95 (SD 21.9) bpm post-CRRT (p = 0.02).

Starting CRRT saw no significant change in noradrenaline dose in either group. Median noradrenaline dose in the ipsilateral group pre-CRRT was 0.12 (0.07–0.28) mcg/kg/min and 0.13 (0.06–0.28) mcg/kg/min post-CRRT (p = 0.95). Median noradrenaline dose in the contralateral group prior to-CRRT was 0.38 (0.15–0.57) mcg/kg/min and 0.40 (0.13–0.58) mcg/kg/min post-CRRT (p = 0.92).

The pre-CRRT noradrenaline dose for the ipsilateral group was significantly different from the pre-CRRT noradrenaline dose for the contralateral group (p = 0.01); the post-CRRT noradrenaline dose for the ipsilateral group was significantly different from the post-CRRT noradrenaline dose for the contralateral group (p = 0.02).

A multivariable linear regression model showed that changes in noradrenaline doses before and after starting CRRT were not significantly affected by changes in physiological variables (e.g. heart rate, MAP, systolic and diastolic blood pressure pre and post CRRT), flow rate (ml/kg/h), ipsilateral or contralateral placement, distance between tips or whether CVDC was upstream or downstream relative to CVC tip.

Conclusions

This study found no difference in distance between CVC and CVDC line tips when placed ipsilaterally or contralaterally. There were no significant adverse changes in haemodynamics or noradrenaline dose when CRRT was commenced in either group.

The contralateral group were a sicker cohort of patients, with higher baseline noradrenaline requirements and heart rates, suggesting that decisions to site lines contralaterally or ipsilaterally may reflect the stage of illness at the time of insertion.

Other potential risks associated with ipsilateral CVC and CVDC placement were not explored but have already been addressed elsewhere in the literature. ⁷