Within two decades, there have emerged three highly pathogenic and deadly human coronaviruses, namely SARS-CoV, MERS-CoV and SARS-CoV-2. The economic burden and health threats caused by these coronaviruses are extremely dreadful and getting more serious as the increasing number of global infections and attributed deaths of SARS-CoV-2 and MERS-CoV. Unfortunately, specific medical countermeasures for these hCoVs remain absent. Moreover, the fast spread of misinformation about the ongoing SARS-CoV-2 pandemic uniquely places the virus alongside an annoying infodemic and causes unnecessary worldwide panic. SARS-CoV-2 shares many similarities with SARS-CoV and MERS-CoV, certainly, obvious differences exist as well. Lessons learnt from SARS-CoV and MERS-CoV, timely updated information of SARS-CoV-2 and MERS-CoV, and summarized specific knowledge of these hCoVs are extremely invaluable for effectively and efficiently contain the outbreak of SARS-CoV-2 and MERS-CoV. By gaining a deeper understanding of hCoVs and the illnesses caused by them, we can bridge knowledge gaps, provide cultural weapons for fighting and controling the spread of MERS-CoV and SARS-CoV-2, and prepare effective and robust defense lines against hCoVs that may emerge or reemerge in the future. To this end, the state-of-the-art knowledge and comparing the biological features of these lethal hCoVs and the clinical characteristics of illnesses caused by them are systematically summarized in the review.

Recently, natural exogenous surfactant replacement has been used in experimental models and clinical trials for the treatment of severe respiratory syncytial virus (RSV) disease. The present study was aimed at verifying this hypothesis and confirming the results of our previous pilot study by assessing the effect of surfactant treatment in mechanically ventilated infants with severe RSV-induced respiratory failure. Multicenter, randomized, controlled study. Six pediatric intensive care units staffed by full-time intensive care physicians. A total of 40 infants (20 treated and 20 controls) with RSV-induced respiratory failure requiring conventional mechanical ventilation (CMV) were randomly assigned to either exogenous surfactant (treated group) or conventional treatment (control group) over a 1-yr period. Fifty milligrams per kilogram of body weight of porcine-derived natural surfactant (Curosurf) was administered. The drug was instilled by means of a syringe attached to a small suction catheter inserted into the endotracheal tube down to its tip, momentarily disconnecting the patient from CMV. The assessment consisted of the following outcome variables: duration of CMV, length of intensive care unit stay, gas exchange, respiratory mechanics, re-treatment need, complications, and mortality. The two groups were similar with regard to demographics, Pediatric Risk of Mortality scores, and baseline Pao2/Fio2, Paco2, and ventilator settings. A marked increase in Pao2/Fio2 and decrease in Paco2 were observed in the treated group after surfactant administration. Hemodynamic parameters remained unchanged throughout the study period. Peak inspiratory pressure and static compliance were similar at baseline in the two groups. A decrease in peak inspiratory pressure and increase in static compliance were observed in the treated group after surfactant administration. Among surfactant-treated patients, 15 received the treatment within 24 hrs of admission, whereas the remainder (five patients) were treated later. Among children who were treated later, three needed an additional dose of surfactant. None of the children treated within 24 hrs needed an additional dose. Duration of CMV and length of stay in the intensive care unit were significantly shorter in the treated group (4.6 ± 0.8 and 6.4 ± 0.9 days, respectively) compared with the control group (5.8 ± 0.7 and 8.2 ± 1.1 days, respectively) (p < .0001). No relevant complications were observed, and all the infants survived. Consistent with our previous study and others, this study shows that surfactant therapy improves gas exchange and respiratory mechanics and shortens CMV and intensive care unit stay in infants with severe RSV-induced respiratory failure.

The recognition that alveolar overdistension rather than peak inspiratory airway pressure is the primary determinant of lung injury has shifted our understanding of the pathogenesis of ventilator-induced side effects. In this review, contemporary ventilatory methods, supportive treatments, and future developments relevant to pediatric critical care are reviewed. A strategy combining recruitment maneuvers, low-tidal volume, and higher positive end-expiratory pressure (PEEP) decreases barotrauma and volutrauma. Given that appropriate tidal volumes are critical in determining adequate alveolar ventilation and avoiding lung injury, volume-control ventilation with high PEEP levels has been proposed as the preferable protective ventilatory mode. Pressure-related volume control ventilation and high-frequency oscillatory ventilation (HFOV) have taken on an important role as protective lung strategies. Further data are required in the treatment of children, confirming the preliminary results in specific lung pathologies. Spontaneous breathing supported artificially during inspiration (pressure support ventilation) is widely used to maintain or reactivate spontaneous breathing and to avoid hemodynamic variation. Volume support ventilation reduces the need for manual adaptation to maintain stable tidal and minute volume and can be useful in weaning. Prone positioning and permissive hypercapnia have taken on an important role in the treatment of patients undergoing artificial ventilation. Surfactant and nitric oxide have been proposed in specific lung pathologies to facilitate ventilation and gas exchange and to reduce inspired oxygen concentration. Investigation of lung ventilation using a liquid instead of gas has opened new vistas on several lung pathologies with high mortality rates. The conviction emerges that the best ventilatory treatment may be obtained by applying a combination of types of ventilation and supportive treatments as outlined above. Early treatment is important for the overall positive final result. Lung recruitment maneuvers followed by maintaining an open lung favor rapid resolution of pathology and reduce side effects. The methods proposed require confirmation through large controlled clinical trials that can assess the efficacy reported in pilot studies and case reports and define the optimal method(s) to treat individual pathologies in the various pediatric age groups.