Beds & staff modifications during the COVID period
As indicated (Figure I, week 10), when the first COVID+ patients were admitted the 55 medical ICU-beds were already almost all occupied by non-COVID patients. Anticipating an overflow of COVID+ patients, the IACU immediately cancelled elective surgical and non-emergency procedures and expanded:
- the surgical ICU, whose capacity rose progressively from 46 to 147 ICU-beds (over 3 weeks), including ephemeral COVID-ICU beds in step-down units,
- the medical ICU department capacity immediately from 55 to 63 beds (+ 15.5%, upper limit due to architectural constraint),
so as to bring our institutional ICU-bed availability to a level 30% above the number of COVID+ patients treated by mechanical ventilation two weeks earlier in Lombardy, Italy (bed/inhabitants: 0.21‰ versus 0.15%) (8).
Anesthesiologists and intensive-care trained nurses were relocated to these facilities at a ratio of “1 nurse for 2 beds”. At national level, full lockdown of the population was decreed on 17 March (week 12). When, at week 19, the number of COVID admissions fell, the number of ICU beds was immediately reduced from 63 to 55 so as to reflect the level of occupancy (Figure 1).
COVID-associated changes in the flow of admissions
During the pre-COVID period (Figure I, left part) regular critical-care treatment was dispensed to 396 COVID- patients, including 37 ICP (9.3%). During the 3-month COVID period (weeks 10 to 23) 547 patients were admitted, including 233 COVID+ patients, of whom 24 were ICP (4.4% of admissions, 10.3 % of COVID patients). There were thus 50% fewer ICP admissions than had been expected during the pre-COVID period. These figures do not correspond to statistical differences in the provision of critical care to either category (number of monthly admissions of either category, proportion of ICP versus others). The transfer of immuno-competent COVID- patients to step-down beds commenced as soon as the first COVID+ patients arrived, so as to avoid the bed-saturation (week 11 to 12) that would have occurred within 3 days with our usual ICU length of stay for non-COVID patients. An immediate stop mechanism was also adopted for non-emergency procedures in anticipation of the possible post-operative saturation of surgical ICU beds. From weeks 12 to 16, bed-saturation occurred despite these measures, although the number of patients who could not be admitted (n =47) to our ICU but who were admitted to surgical ICUs freed by non-emergency procedures stopping was less than 2 patients per day. Strikingly, no COVID- ICP was proposed to our ICU from weeks 10 to 19 (Figure 1). Consequently, access to full critical care was not refused for any ICP.
From weeks 10 to 12, there was a rapid doubling in COVID+ admissions (+76.5% of basal level in week 11, +159% from basal level in week 12). Faced with this wholly unforeseen volume of patients, our IACU decided on health evacuation flights in week 12 (Figure 1) for two reasons: 1) because saturation of medical ICU beds had been reached not just in terms of bed-availability but, rather, on account of the presumed longer stay for COVID+ patients (in comparison with usual length of stay for COVID- patients); 2) because saturation was about to be reached in the institution as a whole (210 ICU-beds, with 208 occupied beds) despite bed-availability adjustments and because the effect of the lockdown on the number of admissions was not expected before week 14 (i.e.: week 12 + 15 days). With the help of distant (>1000 km) hospitals in areas not yet badly affected by the SARS-CoV-2 (including hospitals in other countries), health flight evacuation of 22 immuno-competent COVID+ patients (10% of admitted COVID+ patients) was resorted to from weeks 13 to 15. As noted (Figure I, from week 15), a tangible decrease in COVID+ admissions occurred. Bed-availability therefore increased rapidly, as indicated by the difference between bed-occupancy and bed-availability.
The national lockdown ended on week 20. From week 23 onwards, the COVID episode could be considered as finished in our ICU: COVID+ patients surviving abroad were then progressively repatriated.
Characteristics of ICP with COVID
Clinical characteristics and ICU-stay data of the ICP are reported in Table 1. Twelve (50%) patients had a history of active cancer in the last five years (see histological types below Table 1). One patient had had two different cancers, without genetic link. Three of the oncology patients also had a history of hematological malignancy: one had hyper eosinophilia with increased Immunoglobulin E, one had a history of marginal zone lymphoma and diffuse large B cell lymphoma, and one had a multiple myeloma associated with lambda Immunoglobulin A. Eight patients had a history of hematological malignancy, consisting in lymphoproliferative disorders in 6 of the 8 cases (75%). Within the previous 3 months, 2 patients had undergone autologous stem-cell transplantation (zero allogenic bone-marrow transplantation). Finally, 4 patients had had solid organ transplantation. No HIV patient was hospitalized during this period. Interestingly, 6 patients (25%) displayed monoclonal gamma-pathology.
The severity of acute respiratory distress syndromes is illustrated by the presence of moderate to critical radiological infiltrates in most patients (n=14/17 (82%)), low PaO2/FiO2 ratios, especially in the deceased group, and the recourse to mechanical ventilation in all patients but 2. Non-invasive ventilation proved insufficient for most patients. One patient successfully underwent ECMO for 32 days.
Eleven patients (79%) had a positive lupus anticoagulant. All but one received anticoagulant therapy, 11 (48%) of them receiving a treatment dose: 3 patients developed venous thromboembolism and one patient, with newly diagnosed promyelocytic leukemia, died from a carotid artery occlusion.
Nine patients (37%) developed healthcare-associated infection, chiefly ventilator-associated pneumonia (78%). Only one patient had airway Aspergillus fumigatus colonization, without proof for invasive infection. Interestingly, 67% and 50% of the patients still had a positive PCR for SARS-CoV-2 swab sample at days 21 and 28, respectively.
Survival rates
Figure II shows the actuarial survival of COVID patients, whether ICP or not. At day 28, ICP had a significant decrease in survival as compared with other patients (41.7 % versus 27.3%, p=0.021), but from 2 weeks after admission this difference remained stable until day 56 (p=0.023, not shown). No factor was significantly different between COVID+ ICP depending on whether they survived or not, with the exception of classic scores (SAPSII, SOFA) which were higher in non-survivors (Table I).