Today we need a donor for a heart, lung, kidney or skin. Engineered organs could be created that would allow combat medicine to create onsite a replacement material or organ to maintain the Service Member.
Using modern data processing systems, we could create down to the cellular level a reproduction of a persons specific organ or skin for emplacement into the Service Member. This would use high fidelity 3D printing systems tied to a persons DNA thereby eliminating organ rejection.
The speed of insertion, recovery, and return to function would we increased through the use of nanobots to connect the various blood, skin, and viscera together creating a seamless integration into the wounded service member. This would reduce trauma, scaring, and recovery from major surgery.