Effects of Preoperative Hemoglobin on Microsurgical Reconstruction and Perioperative Blood Transfusion Requirement: A Meta‐Analysis and Systematic Review of the Literature

ABSTRACT Purpose Although blood loss in microsurgical reconstruction is rarely large enough to be life‐threatening, preoperative anemia can be a particular issue in terms of postoperative morbidity, impaired wound healing, and compromised tissue viability. We seek to review the effect of preoperative hemoglobin (Hgb) levels on perioperative blood transfusion (PBT) requirements and complications to guide management of patients with preexisting anemia undergoing reconstruction. Methods PubMed, Embase, and Scopus were queried for relevant articles. Inclusion criteria were as follows: original studies investigating outcomes and PBT requirements in flap‐based reconstruction based on preoperative Hgb levels. Patient and study characteristics were analyzed using descriptive statistics. A meta‐analysis was conducted to assess transfusion requirements across the included studies using Stata (version 18.0 Stata Corp, College Station, Texas, USA). The Fisher method was used to aggregate individual study p values into a single combined value to statistically assess the combined findings, where a p value of