IntroductionThe Cook-Swartz implantable Doppler monitors venous or arterial blood flow from free flaps and can detect free-flap compromise. Previous studies have shown that the use of this Doppler can improve detection and salvage rates as it provides an earlier warning than the current method of clinical assessment. Such studies assert that the implantable Doppler is of great value in monitoring free flaps in current microsurgical units. This systematic review aims to compare the efficacy of the Cook-Swartz implantable Doppler in monitoring free-flap compromise against conventional clinical free-flap monitoring techniques.Methods and analysisVarious electronic databases will be systematically searched for studies that compare the use of Cook-Swartz implantable Doppler with clinical assessment. The selected studies will then have their titles and abstracts screened by two authors. Articles selected after title and abstract screen will have full text downloaded and the complete article will be assessed for suitability. Once the articles have been selected for inclusion, data extraction will take place. For data analysis, the outcomes of the studies will be tabulated, with descriptive statistics performed as appropriate and the detection rate of the Doppler and clinical assessment will be compared and synthesised where possible.Ethics and disseminationThe authors hope to disseminate the findings as widely as possible. This systematic review will be published in a peer-reviewed journal and include a number of recommendations as its conclusion based on the evidence contained within. Given the wide range of specialties now utilising flaps, it will be presented at a wide range of national and international conferences.Protocol Registration in PROSPEROCRD42013005818The literature search and data extraction went on until 28 January 2014. These steps were revised in line with peer review comments.