BACKGROUND: Enhanced recovery after surgery (ERAS) protocols reduce length of stay, complications, and costs for elective surgical procedures. It remains challenging to implement ERAS concepts in the acute trauma patient due to deranged physiological reserve from the penetrating or blunt trauma producing altered physiology. However, systems of care improve access to early intervention and potentially reduce mortality. These consensus guidelines examine optimal pre-hospital, resuscitation-room, intra-, and post-operative treatment, systems of ethical management, and overall care for trauma patients in the post-resuscitation phase of care. The guideline is presented in three parts, this being part 1. METHODS: Experts in aspects of management of trauma surgical patients and intensive care were invited to contribute by the International ERAS Society and IATSIC. PubMed, Cochrane, Embase, and MEDLINE database searches on English language publications were performed for ERAS elements using the patient intervention comparator outcome (PICO) consensus questions created by the expert group. Studies were selected with particular attention to randomized clinical trials, systematic reviews, meta-analyses, and large cohort studies, reviewed, and summarized recommendations were graded using the grading of recommendations, assessment, development and evaluation (GRADE) system. These recommendations based on current best evidence, with extrapolation from elective patient studies, where appropriate, were followed by a modified two-round Delphi method to validate final recommendations. Several ERAS components are already standard of care within national and society guidelines and are endorsed. The bulk of the text focuses on key areas pertaining specifically to trauma care of major trauma and polytrauma in the ICU-requiring group. RESULTS: Overall 37 aspects of trauma care were considered with multiple PICO questions and sub-points. Consensus was reached after two rounds of a modified Delphi process involving all authors, with minor adjustments to some phrasing required, but with 87% overall agreement on all statements (100% agreement on 31 of the main statement sets, prior to minor edits to address the points of difference for the rest with 100% total agreement thereafter). None were rejected outright. The recommendations and level of evidence for each aspect of trauma care that may impact on improved recovery and reduced length of hospital stay are presented with grade of recommendation. CONCLUSIONS: The guidelines relating to initial care and decision-making are presented in part 1 of the Guidelines. These guidelines are based on current best evidence for an ERAS approach to patients who have had major injuries and polytrauma. The guidelines are not exhaustive but collate the best available evidence on important components of care for this patient population. As some of the evidence is extrapolated from elective surgery and non-trauma emergency surgery, some of the components need further evaluation in future studies.