A systematic review on the role of extremity skin temperature as a non-invasive marker for hypoperfusion in critically ill adults in the intensive care setting.

Background: Haemodynamic monitoring is the cornerstone of critical care management. The adequacy of peripheral perfusion has been used as a determinant of cardiovascular system status. Poor cardiac function leads to increased vascular resistance, contributing to reduced tissue perfusion, and it is said to cause a large temperature gradient between the core and the skin. Consequently, skin temperature at the extremities has been proposed as a "proxy" to assess peripheral perfusion. However, this has not been investigated in a systematic way, hence the need for a systematic review of the literature.

Objectives: The objective of this review is to present the best available evidence on extremity skin temperature as a non-invasive marker of hypoperfusion in critically ill adult patients.

Search Strategy: A comprehensive search of major databases was performed to ensure all studies meeting the inclusion criteria were retrieved. The search strategy aimed to find both published and unpublished studies, published in English language, from 1969 to 2010.

Selection Criteria: Randomised controlled trials, quasi-experimental studies, non-randomised controlled trials, and before and after studies that investigate the role of skin temperature as a marker of hypoperfusion were included. Observational, correlational studies were included due to the lack of studies with high level of evidence.Male and female critically ill adult patients (aged 18 years and above) admitted to the intensive care setting.The review considered studies that evaluate the role of extremity skin temperature monitoring in the diagnosis of hypoperfusion. Skin temperature monitored subjectively via touch or palpation and objectively via skin temperature monitoring devices.Measures of skin temperature (e.g. toe temperature, core-peripheral temperature, etc.) and markers of perfusion (e.g. cardiac output, mean arterial pressure, heart rate, central venous pressure, etc.).

Critical Appraisal, Data Collection & Data Synthesis: Eligibility of papers were assessed independently by the two reviewers. Ten studies were assessed for methodological quality with a modified Critical Appraisal Checklist. After this process, five were selected. A newly-developed data extraction tool was used to gather specific information from the selected studies. Due to the heterogeneity of the studies' methodology, the results of this systematic review were presented in a narrative summary.

Results: There were three studies which support the use of extremity skin temperature as a marker of hypoperfusion and two studies which do not support the use. These results reveal the apparent lack of consensus in the studies as to whether or not extremity skin temperature is an accurate and reliable marker of hypoperfusion.

Conclusions: The use of extremity skin temperature as a "proxy" for hypoperfusion cannot be validated or recommended due to the paucity of definitive evidence.The review is unable to provide a definitive recommendation to guide clinical practice in this area. Nonetheless, the assessment of extremity skin temperature may be feasible in the general wards for identifying patients at risk because of its ease of use and non-invasive nature.Higher quality research should be conducted to determine if extremity skin temperature has a putative role as a non-invasive marker of hypoperfusion in critically ill adults.