Background There is increasing international recognition of the importance of palliative care for all intensive care unit (ICU) patients regardless of prognosis. The palliative care needs of ICU patients are largely unknown but individual studies focused on specific groups have indicated a high symptom prevalence. In order to target interventions effectively, a greater understanding of symptom burden is needed.

Aims To determine the prevalence of physical, psychological and spiritual symptoms experienced by ICU patients.

Methods Six electronic databases were searched from inception to 2018. The concepts ‘intensive care’, ‘symptoms’ and ‘prevalence’ were used to identify quantitative studies that reported data on the prevalence of three or more symptoms in adult ICU patients with any diagnosis. Additional data sources included Google Scholar and reference list and citation searches of all included studies. Prevalence was documented for each symptom identified. When raw data permitted, random-effects meta-analysis with double arcine transformation was used to calculate pooled prevalence estimates and 95% confidence intervals. Heterogeneity was assessed using the I2 statistic.

Results Fourteen studies were included, providing data from 1602 ICU patients. In total, 31 physical, 11 psychological and two spiritual symptoms were identified. Pain, dyspnoea and anxiety were the most frequently described. Ten studies contributed to the meta-analysis, which was performed for fifteen symptoms. The most prevalent symptoms were fatigue (95%; 95% confidence interval 90–98), dyspnoea (77%; 61–89), anxiety (76%; 52–94), anorexia (70%; 31–97) depression (68%; 43–89), drowsiness (67%; 42–88), thirst (66%; 43–86) and pain (54%; 35–73). Wide confidence intervals and high I2 values signified considerable heterogeneity.

Conclusion ICU patients experienced a significant symptom burden and were not adequately symptom controlled. The heterogeneity observed influences the validity and generalisability of the results. However, despite limitations, this review provides a valuable insight into the unmet palliative care needs of ICU patients.