Severe A-line infections in COVID-19 patients: A novel management algorithm in an emergency setting.

Dear Sir,

Since its outbreak, COVID-19 caused almost 39,000 official deaths in Italy, with thousands of patients needing ICU management. This dramatic situation was already thoroughly showed and described by many colleagues fellow-countrymen. Due to the sudden and complete ICUs saturation we were forced to hospitalize a huge number of extremely critical patients in non-ICU inpatient wards.

COVID patients diagnosed with Acute Respiratory Failure (ARF) required several ABGs monitoring per day. To avoid repeated painful arterial punctures, they received an indwelling radial artery catheter (A-line) to provide continuous access to arterial blood. We unexpectedly noticed a significantly higher incidence of A-line infection compared to what is showed in literature.

All those patients who received a diagnosis of cath-related infection were clinically evaluated by an expert plastic surgeon along with an infectious disease specialist. The catheter was always removed and tip microbiological cultures were always performed. Patients were treated with broad-spectrum empirical antibiotics (Ciprofloxacin 400 mg plus Clindamycin 600 mg daily, both parenterally administered).

From February 23rd to June 23rd (121 days) 519 patients were admitted to our hospital with a SARS-CoV-2-positive severe interstitial pneumonia. Sixty-nine (69) of them needed ICU management and/or required invasive mechanical ventilation and therefore were excluded from our analysis. A total of 450 patients were hospitalized in non-ICU “COVID-19″ wards (including Sub-Intensive Care Unit or Rehabilitation Unit). Eighty-eight (88) of them were diagnosed with ARF responsive to non-invasive mechanical ventilation and required a radial A-line placement.

Twelve patients (14%. Mean age: 61.8 yo) experienced fever and intense tenderness at the A-line site averagely 124.4 h after its placement. All patients received methylprednisolone, six of them were treated with additional hydroxychloroquine and just two patients also received Tocilizumab.

Six patients (7%) experienced a clear improvement in tenderness associated with body temperature lowering after 24 h from the antibiotic treatment starting.

The remaining six patients (7%) rapidly worsened in few hours even with antibiotic therapy, developing extended subcutaneous cellulitis, local abscess and pyogenic flexor tenosynovitis of the Flexor Pollicis Longus and Flexor Superficialis of the second finger tendons (clinically showing a strong reduction of fingers active flexion associated with extremely severe pain elicited by fingers passive extension).

For each of them, the treatment included: surgical incision and drainage of the abscess; tendon sheath irrigation and drainage with an accurate surrounding necrotic tissue debridement; ligation of the radial artery; we always let surgical wounds heal by secondary intention; splint application to temporary immobilize fingers in slight flexion. The surgical procedure was performed after a mean time of 23 h from the diagnosis of infection. Patients characteristics are outlined in Table 1 .

Table 1

Patients characteristics. Time to Diagnosis: hours from arterial line placement and clinical diagnosis of soft tissue infection. Time to surgery: hours from diagnosis to entrance in the Operatory Room. MSSA: methicillin-sensitive Staphylococcus Aureus. MSSE: methicillin-sensitive Staphylococcus Epidermidis. MRSE: methicillin-resistant Staphylococcus Epidermidis. Coag. Neg. Staph.: Coagulase-negative Staphylococcus.

Patient	Age	Sex	Hydroxychloroquine	Methylprednisolone	Tocilizumab	pathogen	time to diagnosis (h)	time to surgery (h)
1	57	male	yes	yes	yes	MSSA	130	23
2	67	male	yes	yes		Coag. Neg. Staph.	127
3	59	male	yes	yes		MSSE	116	26
4	75	male	yes	yes		MSSE	119	23
5	63	male	yes	yes	yes	MSSA	140
6	71	male		yes		Coag. Neg. Staph.	152
7	60	male	yes	yes		MSSE	118
8	63	male		yes		Coag. Neg. Staph.	119	22
9	58	male		yes		Coag. Neg. Staph.	116
10	70	male		yes		Coag. Neg. Staph.	125
11	40	male		yes		MRSE	116	25
12	59	male		yes		MSSA	115	19

No functional loss or systemic infection were observed following the surgical intervention. All patients experienced rapid improvement of symptoms as well as a notable reduction of pain during active fingers flexion. Figure 1 shows case n.3 ten days after the surgical debridement.

Figure 1

Severe soft tissue infection with skin necrosis and volar incisions for tendon sheaths irrigation, after 10 days from the surgical intervention. The patient developed a pseudo-aneurism with infection and extensive soft tissue involvement. It is notable the extensive defect on the distal radial portion of the forearm.

A wide cluster of immunomodulating drugs have been commonly administered in COVID-19 patients worldwide. Between them, just the glucocorticoids still maintain a therapeutic evidence in the light of the latest updated clinical studies.

In our study, 14% of the patients with an A-line developed a local soft tissue infection. Half of them (7%) experienced an extremely severe soft tissue infection extended to tendon sheaths and requiring an immediate surgical debridement. In the updated literature reports, the incidence of local infection in radial artery line placements is around 0.8%.

We believe that this significantly higher reported incidence of complications is caused by different factors. First, immunomodulatory drugs decrease the immune response against bacterial infections. Furthermore, considering the national emergency setting, A-lines were often placed by not expertized personnel and/or paying less attention to antispesis. Lastly, we think that the biofilm deposition (produced by a combination of host factors – e.g. fibrinogen and fibrin – and microbial products) on the external and internal surface of vascular catheters could be boosted by the COVID-related elevated levels of fibrinogen and d-dimer in the serum, increasing the infectious risk in these patients.

Considering the rapid progression registered in half of the affected cases, we propose a useful diagnostic-therapeutic algorithm (Figure 2 ): clinical monitoring every 6 h after the A-line removal and splint application for the first 48 h; if signs of infection are noticed, we strongly encourage immediate initiation of parenteral antibiotic therapy with Ciprofloxacin 400 mg plus Clindamycin 600 mg once daily, clinically assessing signs of local infection every 3 h; if purulent infection and/or clinical evidence of tenosynovitis are noticed, we suggest an immediate surgical debridement.

Figure 2

Proposed management algorithm for severe infections following radial A-line removal in COVID-19 patients, in an emergency setting. The antibiotic therapy is parenterally administered. The clinical monitoring must be performed by an experienced surgeon.

Following the overmentioned protocol, we did not observe permanent functional impairment or systemic progression of the infection. Local symptoms improved quickly and the hand function was preserved.

Declaration of Competing Interest

None