Marga Hoogendoorn

112 We also compared the baseline characteristics of the included patients from the six hospitals in our study with the patients of all other hospitals in the NICE database (appendix 6) We found a difference in the distribution of patients between the groups. We found a significant lower number of medical patients (32.8% versus 51.8%, p<0.001), a higher number of elective surgery patients (49.6% versus 35.0%, p<0.001) and emergency surgical patients (17.5% versus 12.6%, p<0.001) in our study group compared to the patients in all hospitals. Also the Apache Acute Physiology Score (APS)-score and both the ICU and in-hospital mortality were higher in COVID-19 patients in our study group compared to COVID-19 patients in all other hospitals in the NICE database. Results workload per nurse We found a significant higher number of patients per nurse in the COVID-period compared to the non-COVID period (Median (IQR) 1.1 (0.8 – 1.5) versus 1.0 (0.7 – 1.3), p<0.001). Figure 1 shows the differences in number of patients per ICU nurse per month of the COVID and the non-COVID periods. The number of patients per ICU nurse was significant higher in the months April and May in the COVID-period compared to the non-COVID-period, with an increase of 30% in April 2020 compared to 2019 (Median (IQR) 1.3 (0.9 – 1.8) versus 1.0 (0.6 – 1.2), p<0.001) (Table 3). In April 2020 some ICU nurses took care for up to 5 patients per shift. This is more than double the maximum of two patients per nurse as stated by the Dutch Guidelines for Intensive Care. We further found a higher Nursing Activities Score per ICU nurse in the COVID-period compared to the non-COVID-period (Median (IQR) 69.8 (50.1 – 90) versus 46.6 (26.4 – 70.7), p<0.001). Figure 2 shows the differences in Nursing Activities Score per ICU nurse per month of the COVID and the non-COVID periods. The mean Nursing Activities Score per ICU nurse was significant higher in each month of the COVID-period compared to the non-COVID-period with a peak of 98% increase in in April 2020 compared to 2019 (Median (IQR) 89.6 (63.8 – 117.2) versus 45.2 (27.5 – 68.7), p<0.001) (Table 3). Table 3. Patients per nurse and NAS per nurse per month Patients per nurse – Median (IQR) NAS per nurse - Median (IQR) 2020 2019 p-value 2020 2019 p-value 1.1 (0.9 – 1.4) 1.0 (0.6 – 1.3) <0.001 70.1 (55.7 – 91.3) 45.6 (27.0 – 72.1) <0.001 1.3 (0.9 – 1.8) 1.0 (0.6 – 1.2) <0.001 89.6 (63.8 – 117.2) 45.2 (27.5 – 68.7) <0.001 0.9 (0.7 – 1.2 1.0 (0.6 – 1.3) 0.291 64.9 (46.4 – 79.1) 45.9 (24.5 – 70.8) <0.001 1.3 (0.9 – 1.3) 1.0 (0.6 – 1.2) 0.057 56.6 (37.7 – 74.3) 48.8 (26.7 – 71.5) 0.002