Midline peripheral catheters inserted in the superficial femoral vein at mid-thigh: Wise choice in COVID-19 acute hypoxemic respiratory failure patients with helmet continuous positive airway pressure.

BACKGROUND: During coronavirus disease 2019 (COVID-19) pandemic, Helmet Continuous Positive Airway Pressure (h-CPAP) has been widely used to treat Acute Hypoxemic Respiratory Failure (AHRF). In COVID-19 patients undergoing h-CPAP a simple short peripheral catheter could be insufficient. According to the European Recommendations for Proper Indication and Use of Peripheral venous access consensus, a stable peripheral Vascular Access Device is indicated for intravenous treatment compatible with the peripheral route scheduled for more than 1 week. OBJECTIVE: The aim of this prospective study was to evaluate the performance and the potential complications of superficial femoral midline catheters (SFMC) inserted in the Superficial Femoral Vein by direct Seldinger technique with peripheral tip (Arrow®, Teleflex; 20 cm length four FR single lumen and seven FR dual lumen) in AHRF COVID-19 patient. Complications were divided in early (accidental puncture of superficial femoral artery (APSFA); accidental saphenous nerve puncture (ASNP); bleeding) and late (Catheter Related Thrombosis (CRT); Catheter-Related Bloodstream Infections (CRBSI); Accidental Removal (AR); persistent withdrawal occlusion (PWO)). METHODS: From 1st October 2020 to 30th June 2021 we conducted a prospective observational study in COVID-19 sub-intensive wards at Luigi Sacco Hospital (Milan). RESULTS: Hundred seventy five SFMC (mean dwell time 11.1 ± 9.8 days) were implanted in COVID-19 patients, 107 (61.1%) during h-CPAP treatment (10.5 ± 8.9 days), the remaining 68 (38.9%) in patients with severe disease. We recorded two minor immediate/early complications (APSFA without sequelae) and no major complications.The long-term follow-up registered four CRBSI (2.3%-2.5/1000 catheters days (CD)), five CRT (2.9%: 2.6/1000 CD), 22 AR (12.6%; 11.4/1000 CD), 38 PWO (36.5%), 34 of which occurred due to fibroblastic sleeve (32.7%). CONCLUSIONS: SFMC proved to be safe, easy and time-saving. It could be implemented, after a careful benefits and risks evaluation, in particular settings such as h-CPAP, delirium, bleeding risk factors and palliative care patients.

Pulsed-wave Doppler for ultrasound-based tip location using bubble test: A pilot study.

BACKGROUND: MicroBubbles Time test (MBT), consisting in the rapid infusion of saline with addition of air microbubbles, visualized by B-mode echocardiography, represents a potential alternative to Intracavitary ECG (IC-ECG) and chest X-ray for central venous catheters (CVCs) tip location. Even if promising, this technique lacks of standardization: a clear time cut-off between bubble infusion and their detection in heart's right chambers hasn't been yet established. At these regard, microbubbles could be also detected as microembolic signals (MES) with an alternative ultrasound technique: the pulse wave Doppler (PW). OBJECTIVE AND METHODS: The first aim of this pilot study is to establish agreement of MBT with PW test (MBT-PW) compared with reference standard IC-ECG and normal MBT for tip location on CVCs. Corrected tip's position was established through reference standard IC-ECG, afterward MBT-PW was performed, with the sample volume placed at tricuspid valve to detect MES simultaneously with micro-bubbles injection in CVCs. The second aim was to evaluate inter-observer variability for MES detection and grading. RESULTS: Eight patients were enrolled; we obtained three records for each patients (24 with MBT and 24 with MBT-PW, the two techniques were acquired simultaneously). Inter-methods agreement through reference standard IC-ECG versus MBT-PW and MBT versus MBT-PW methodic was satisfying (Cohen's kappa value = 1). MBT-PW and MBT signals were recorded within the first heart beat after microbubble infusion in all patients. Mean time delay thorough MBT-PW and MBT was 0.76 ±0.07 and 0.78 ± 0.07 s respectively; Intraclass correlation coefficient was 0.992 (95% CI: 0.981-0.996) suggesting excellent correlation. Inter-observer variability for positive MBT-PW evaluation was optimal (Cohen's kappa value was 1), while indicated substantial agreement for MES grade evaluation (Fleiss' Kappa value was 0.704; 95% CI: 0.328-1.000). CONCLUSIONS: Our study supports agreement between MBT-PW and reference standard IC-ECG for tip location. Satisfactory agreement was observed also for MBT-PW and MBT.