Effect of age on resolution of ventilator-associated pneumonia

Introduction

To study the clinical and paraclinical response to therapy in patients with ventilator-associated pneumonia (VAP).

Methods

A prospective, 4-year study of 450 patients ventilated over 48 hours. Patients were compared according to four age groups: Group I (<35 years), Group II (35–55 years), Group III (55–79 years) and Group IV (>80 years). Patients and VAP characteristics, ICU and hospital lengths of stay (LOSs), duration of mechanical ventilation (MV)–intubation (TT), patient outcome and the first day of normalization of each clinical and paraclinical parameter were studied using Pearson's chi-square test and one-way ANOVA.

Results

One hundred and thirty-four patients developed VAP. Twenty-five (18.6%) patients of Group I had (mean ± SD) APACHE II score 16.5 ± 3.6, MV 19.08 ± 7.8, TT 21.7 ± 8.4, ICU LOS 25.04 ± 11.5 days, hospital LOS 18.4 ± 10.3 days, ICU mortality 3 (12%), hospital mortality 0 (0%). Thirty-eight (28.4%) patients of Group II had APACHE II score 18.5 ± 5.7, MV 24.08 ± 10.8, TT 29.7 ± 10.6, ICU LOS 33.04 ± 12.5 days, hospital LOS 28.4 ± 11.3 days, ICU mortality 5 (20.8%), hospital mortality 6 (21.4%). Sixty (44.8%) patients of Group III had APACHE II score 21.4 ± 5.6, MV 31.1 ± 16.5, TT 32.8 ± 16.8, ICU LOS 37.04 ± 13.8 days, hospital LOS 34.2 ± 14.1 days, ICU mortality 15 (25%), hospital mortality 16 (26.6%). Ten (7.5%) patients of Group IV had APACHE II score 26.3 ± 4.5, MV 41.6 ± 10.5, TT 45.8 ± 14.7, ICU LOS 49.04 ± 15.2 days, hospital LOS 47.6 ± 18.7 days, ICU mortality 3 (30%), hospital mortality 5 (50%). The APACHE II score (P < 0.001), duration of MV (P < 0.02) and TT (P < 0.04), hospital mortality (P < 0.001), hospital LOS (P < 0.01), and MODS (P < 0.04) differ statistically significantly. ICU mortality (P < 0.4), CPIS (P < 0.7), and duration of antibiotic treatment (P < 0.6) did not differ significantly. VAP was caused by MDR Gram(-) microorganisms, except for three cases caused by MRSA (P < 0.8). Time resolution for temperature was 7 days (6.6. ± 1.1, P < 0.1), leucocyte 6 days (5.8 ± 1.2, P < 0.5), hemodynamic stability 5 days (4.8 ± 0.8, P < 0.3), normalization of PaO₂/FiO₂ 4 days (3.9 ± 0.7, P < 0.07), and microbiological eradication 10 days (9.3 ± 1.1, P < 0.3). Colonization after VAP resolution was higher in the elderly patients (P < 0.02).

Conclusion

Age does not influence the clinical response to therapy. Patients in whom the tracheobronchial aspirates were not sterilized after the resolution of VAP are at higher risk of a longer time of hospitalization and of dying after discharge from the ICU.