The potential role of ICU capacity strain in COVID-19 mortality: comparison between first and second waves in Pavia, Italy
Journal of Anesthesia, Analgesia and Critical Care volume 1, Article number: 8 (2021)
To the Editor,
In novel coronavirus disease (COVID-19) pandemic, a high mortality rate was reported during wave 1, particularly when COVID-19 load exceeded 100% ICU capacity . With better knowledge of the disease [2, 3], a lower mortality was expected in wave 2; however, similar mortalities were reported for hospital/ICU populations . Within the same wave, in-hospital mortality was lower once past the peak of hospital affluence [1, 5], suggesting a role of ICU facilities’ availability. However, their actual role remains unclear since mortality was high also in non-overwhelmed healthcare systems .
To test if disproportion between ICU facilities and hospitalized patients impact COVID-19 mortality, we compared the first 8 weeks of waves 1 vs. 2 in Pavia (Lombardy, Italy). ICU-timing (time from hospital to ICU admission), percentage of COVID-19 hospitalized patients admitted to ICU, and percentage of intubated patients in ICU were considered ICU capacity strain’s markers. All patients during wave 2 received steroids as appropriate . Local ethic committee approved the study.
Patients’ characteristics are in Table 1. In wave 1, a steep increase of ICU COVID-19 patients reached a peak of 64 on day 34 (Fig. 1A); a plateau phase lasted 14/56 days (25.0%); thereafter, a reduction was observed. In wave 2 (Fig. 1B), a slower increase achieved a lower peak (54 patients) on day 40 and lasted 4/56 days (7.1%; p=0.010).
At day 56 of wave 1, patients admitted to ICU were 139, ICU mortality was 54/84 (64.3%), patients still in ICU were 55 (39.6%), and their follow-up ICU mortality was 14/55 (25.5%), lower than in the beginning of the same wave (p<0.0001).
At day 56 of wave 2, patients admitted to ICU were 119, ICU mortality was 18/74 (24.3%; p<0.0001 vs. wave 1), patients still in ICU were 45 (37.8%), and their follow-up ICU mortality was 16/45 (35.6%), similar to the first 8 weeks (p=0.2133). Findings in ward patients are displayed in Fig. 1C, D.
In waves 1 and 2, hospital mortality was in overall ICU patients 48.9% and 30.3% (p=0.0033), in intubated patients 50.7 and 36.7% (p=0.0410), in ward patients 33.3% and 19.6% (p<0.0001), respectively.
Wave 2 determined a lower ICU strain: patients that could be treated in ICU were 17.7 vs. 13.1% (relative increase 35.1%; p=0.0104); ICU-timing was shorter (57±92 vs. 90±91 h; p=0.0047), with patients admitted to ICU within 48 h 58.0 vs. 40.3% (p=0.0059); and intubation was less frequent (75.6 vs. 96.4%; p<0.0001).
ICU-timing was resulted in an independent risk factor for hospital mortality when adjusted for age, gender, and need of invasive ventilation (p<0.0001).
The improvement of ICU and ward patients’ outcome exceeded what expected from steroids’ introduction , supporting that other factor may have a role . ICU strain was significantly higher during wave 1. Moreover, patients were admitted to ICU later, when intubation was almost unavoidable, which may increase mortality . ICU-timing was an independent predictor of mortality, suggesting intensive care should be considered a time-dependent treatment for COVID-19 patients.
In conclusion, COVID-19 mortality notably decreased in wave 2 at our institution; beyond the benefits of a deeper knowledge of the disease, lower ICU capacity strain and timelier ICU admission may have played a role.
Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
Novel coronavirus disease
Intensive care unit
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The authors would like the names of the individual members of the group COVID-19 Pavia Crisis Unit to be searchable through their individual PubMed records. COVID-19 Pavia Crisis Unit: Carlo Marena, MD (San Matteo Hospital, Pavia, Italy); Monica Calvi, PharmD (San Matteo Hospital, Pavia, Italy); Giuseppina Grugnetti, BSN (San Matteo Hospital, Pavia, Italy); Alba Muzzi, MD (San Matteo Hospital, Pavia, Italy); Raffaele Bruno, MD (San Matteo Hospital, Pavia, Italy); Paolo Lago (San Matteo Hospital, Pavia, Italy); Gianluigi Marseglia, MD (San Matteo Hospital, Pavia, Italy); Stefano Perlini, MD (San Matteo Hospital, Pavia, Italy); Alessandra Palo, MD (San Matteo Hospital, Pavia, Italy); Fausto Baldanti, MD (San Matteo Hospital, Pavia, Italy); Luigi Oltrona Visconti, MD (San Matteo Hospital, Pavia, Italy); Marco Benazzo, MD (San Matteo Hospital, Pavia, Italy); Carlo Nicora, MD (San Matteo Hospital, Pavia, Italy); Antonio Triarico, MD (San Matteo Hospital, Pavia, Italy); Vincenzo Petronella, MD (San Matteo Hospital, Pavia, Italy); Antonio Di Sabatino, MD (San Matteo Hospital, Pavia, Italy); Marco Vincenzo Lenti, MD (San Matteo Hospital, Pavia, Italy); Luca Civardi, MD (Anesthesia and Intensive Care, San Matteo Hospital, Pavia, Italy); Fabio Sciutti, MD (Anesthesia and Intensive Care, San Matteo Hospital, Pavia, Italy); Giuseppe Maggio, MD (Anesthesia and Intensive Care, San Matteo Hospital, Pavia, Italy); Michele Pagani, MD (Anesthesia and Intensive Care, San Matteo Hospital, Pavia, Italy); Giuseppe Sala Gallini, MD (Anesthesia and Intensive Care, San Matteo Hospital, Pavia, Italy); Giuseppe Rodi, MD (Anesthesia and Intensive Care, San Matteo Hospital, Pavia, Italy).
Ethics approval and consent to participate
The study was approved by local ethic committee.
Consent for publication
All the patients signed an informed consent for data publication.
FM received fees for lectures from GE Healthcare, Hamilton Medical, SEDA SpA, outside the present work. SM received fees for lectures from GE Healthcare, outside the present work. A research agreement is active between University of Pavia and Hamilton Medical. The other authors declare no conflict of interest.
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On behalf of COVID-19 Pavia Crisis Unit
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Mojoli, F., Cutti, S., Mongodi, S. et al. The potential role of ICU capacity strain in COVID-19 mortality: comparison between first and second waves in Pavia, Italy. J Anesth Analg Crit Care 1, 8 (2021). https://doi.org/10.1186/s44158-021-00007-6
- COVID-19 waves
- ICU organization
- ICU capacity
- ICU preparedness
- COVID-19 mortality