Age-dependent impact of occult hypoperfusion on outcome in polytrauma

Introduction: Occult hypoperfusion (OH) is characterized by normal vitals in combination with inadequate tissue oxygenation. OH is associated with impaired outcome, and especially in severely injured and older patients.

Objectives: The goal of the current study is to determine the impact of OH in different age groups on outcome in polytrauma.

Patients & methods: Adult polytrauma patients (ISS>16) were included during a 19-year time period. The following groups were compared: Gr. ADults (aged: 30-59y), Gr. OLDer adults (aged: 60+y). OH was defined as Lactate > 2 mmol/l plus SBP > 90 mmHg and PR < 120 bpm. Shock was defined as SBP < 90 or PR > 120. The impact of OH on outcome was compared between groups. The following parameters were studied: Intensive Care Unit (ICU)-stay, length of hospital stay (HLOS), complication rates and mortality.

Results: 1,782 patients were identified, of whom 1,067 were selected for group AD and 715 older adult patients were found. In ADults, ICU-stay and HLOS did not differ significantly between shock and OH patients (respectively P=0,43 and P=0,80). In this group, mortality peaked in shock patients (39%), and was also significantly higher after OH (20%) than in normal patients (8%). In contrast, older patients were longer hospitalized after shock than OH (respectively 16 (SD:21) vs. 10 (SD:14), P=0.004). Mortality was higher after shock than in OH-cases, but did not differ between normal and OH-patients in the OLD-group.

Conclusion: Occult hypoperfusion in polytrauma is associated with increased mortality in patients aged between 30 and 59 years. In older patients, no difference in morbidity or mortality were found between OH and normal patients. These results are in contrast with findings from literature on less severely injured patients and imply that OH is an important risk factor for impaired outcome in middle-aged patients, rather than in the elderly.

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