Background and Goal of Study:
When pain ceases serving any protective function, and lasts more than 3 months it is defined as persistent. Over half of the patients treated in intensive care units (ICU) report experiencing pain during ICU stay and the incidence of pain does not differ in surgical and medical patients. Many ICU patients develop persistent pain after discharge. Persistent pain has notable adverse impact in both personal and societal level. It lowers the quality of life and causes large societal costs by burdening the healthcare system and lowering the economical productivity. As the results of individual studies vary we decided to review the literature systemically in terms of persistent pain after intensive care.

Materials and Methods:
A large-scale search of several relevant databases was conducted to find appropriate studies. The eligibility criteria for the studies were: focus on adult (≥18 years) ICU patients, focus on persistent pain (≥2 months), study design RCT or observational study and the article reported in English. The screening of the studies was conducted independently by each reviewer. Quality of the included studies was assessed using the GRADE system. The systematic review is registered in PROSPERO database (register number CRD42016041489).

Results and Discussion:
The literature search provided 16,683 publications and after removal of duplicates 8,888 of studies remained. After screening of the titles and abstracts 77 of articles were examined in detail. 5 articles meeting the inclusion criteria were included in the review. Another database search identified 2 additional eligible studies. The overall quality of the evidence was weak because of the observational design of the studies.
The incidence of persistent post-ICU pain was 28-49% at least 3 months after ICU discharge. Some of the identified risk factors were increased age, pain during ICU stay, length of hospital stay and ventilation hours but results concerning risk factors were inconsistent.


11 / Persistent post-ICU pain: a systematic review