The comparison of the hospital admissions and the use of other healthcare resources that occurred in the year prior to the inclusion in the study and the year of follow-up are shown in Table 3.
Although information regarding hospital admissions and the use of interventions was also obtained from the cost diaries, for this study data from the birth registration forms were used in order to strengthen the validity of the research, since it was expected that the data registered in these forms is more reliable.
The strengths of our study include the relatively long study period using ER data with a substantial amount of admissions and the use of a flexible statistical approach to examine distributed lag and non-linear effects of temperatures on cardiorespiratory morbidity.
Predicting variables with prognostic value are the hemoglobin content, the APACHE II test score on admission and the use of vasoactive drugs and of diuretics.
It is difficult to predict which patients will benefit from ICU admission, and the use of scoring systems has been proposed to inform clinical decision-making.
Finally, older age, a shorter time to ROSC, the presence of a non-shockable rhythm, high white blood cells count and CRP levels or low platelets count on admission and the use of corticosteroids were independently associated with the presence of lymphopaenia on admission in those patients without corticosteroids or immunosuppressive therapy (Additional file 1: Supplemental Tables 4 and 8).
In IHCA patients, older age, a shorter time to ROSC, high white blood cells count and CRP levels on admission and the use of corticosteroids were independently associated with the presence of lymphopaenia on admission (Additional file 1: Supplemental Tables 1 and 5).
Using the same statistical approach, older age, the absence of bystander CPR, a non-shockable initial rhythm, a non-cardiac aetiology of the arrest, high blood lactate levels on admission and the use of vasopressors were independent predictors of ICU mortality (Table 4), but lymphopaenia was not (OR 1.367 [0.787–2.567; p = 0.26).
Immunodeficiency was a major risk factor for ICU admission, and the use of cART was highly beneficial.
On ICU admission, demographic data (age, gender), type of admission (surgical or medical), presence of shock [ 15], previous history of chronic obstructive pulmonary disease, administration of diuretics, volume and type of fluid administered before ICU admission, and the use of mechanical ventilation were recorded.
The admission rate and the use of ambulances increased steadily and significantly.
