*9.1.2 Heart rate (HR)*

Heart rate (HR) was studied and correlated with the development of CAL in some studies [126–128]. On POD 2 and 3, with an HR threshold higher than 89/min, the sensitivity and specificity were 62.5% and 89.2%, respectively [127]. As abovementioned, HR higher than 100/min is a clinical criterion included in the DULK score [129].

## *9.1.3 Respiratory rate (RR)*

In some studies, **respiratory rate (RR)** was also correlated with CAL development [126–129]. The RR of patients with CAL was significantly higher from POD1 to 7. RR above 30/min or 20/min are included in the DULK score and its modified version, respectively [126, 129].
