Clinical features and predictors of severity in COVID-19 patients with critical illness in Singapore

Abstract

We aim to describe a case series of critically and non-critically ill COVID-19 patients in Singapore. This was a multicentered prospective study with clinical and laboratory details. Details for fifty uncomplicated COVID-19 patients and ten who required mechanical ventilation were collected. We compared clinical features between the groups, assessed predictors of intubation, and described ventilatory management in ICU patients. Ventilated patients were significantly older, reported more dyspnea, had elevated C-reactive protein and lactate dehydrogenase. A multivariable logistic regression model identified respiratory rate (aOR 2.83, 95% CI 1.24-6.47) and neutrophil count (aOR 2.39, 95% CI 1.34-4.26) on admission as independent predictors of intubation with area under receiver operating characteristic curve of 0.928 (95% CI 0.828-0.979). Median APACHE II score was 19 (IQR 17-22) and PaO2/FiO2 ratio before intubation was 104 (IQR 89-129). Median peak FiO2 was 0.75 (IQR 0.6-1.0), positive end-expiratory pressure 12 (IQR 10-14) and plateau pressure 22 (IQR 18-26) in the first 24 h of ventilation. Median duration of ventilation was 6.5 days (IQR 5.5-13). There were no fatalities. Most COVID-19 patients in Singapore who required mechanical ventilation because of ARDS were extubated with no mortality.

Figure 1

Summary of univariate odds ratios and multivariable logistic regression model. (A) AUC for full model 0.928 (95% CI 0.828–0.979, p < 0.0001). (B) Simplified model includes the following categorical variables as risk factors for intubation: neutrophil count > 4 × 10⁹ L and respiratory rate > 18. AUROC for this model is 0.889 (95% CI 0.779–0.956, p = 0.0002). AUROC: Area under receiver operating characteristic.

Figure 2

(a) Portable supine CXR shows intubated patient with diffuse mixed patchy ground glass opacities with consolidation predominantly in the peripheries. There is no zonal predilection, hilar adenopathy or associated pleural effusion. (b) Axial contrast enhanced CT (CECT) image across the lower zones of the lungs confirms CXR features. There are multifocal areas of consolidation in the peripheries, notably in the dependent regions of the lower lobes. Ground glass opacities are more diffusely distributed. Air bronchograms are salient throughout the lower lobes. There is notable absence of pleural effusions or adenopathy in the mediastinum (not shown).

Figure 3

(a) Portable supine CXR shows intubated patient with dense consolidation in bilateral middle and lower zones. There is relative sparing of the upper zones and costophrenic recesses. There is no associated pleural effusion. (b) Axial CECT image across the middle zone of the lungs shows consolidation with air bronchograms throughout the affected lobes, particularly bilateral lower lobes. The more anterior segments show some degree of organizing consolidation (arrow). As with other cases in our series, there is absence of pleural effusions or adenopathy in the mediastinum (not shown). This pattern of confluent consolidation was a less typical observation.

Figure 4

(a) Portable supine CXR shows intubated patient with mixed ground glass opacification and consolidation in the peripheries of the middle and lower zones. There is relative sparing of the central and upper zones. There is no associated pleural effusion. (b) Axial high resolution reconstructed CECT image across the middle zone of the lungs shows extensive bilateral lung disease with relative sparing of the anterior lobar segments. Consolidation is most notable in the superior segments of the lower lobes with smaller foci in the posterior segment of the right upper lobe. There are ground glass opacities in the lateral regions, distinct from the non-diseased medial portions of the right upper and left lingular lobe.