38 C.F.R. § 17.120

To the extent allowable, payment or reimbursement of the expenses of emergency treatment, not previously authorized, in a private or public (or Federal) hospital not operated by the Department of Veterans Affairs, or of any emergency treatment not previously authorized including transportation will be paid on the basis of a claim timely filed, under the following circumstances:

(a) For veterans with service connected disabilities. Emergency treatment not previously authorized was rendered to a veteran in need of such emergency treatment:

(1) For an adjudicated service-connected disability;

(2) For nonservice-connected disabilities associated with and held to be aggravating an adjudicated service-connected disability;

(3) For any disability of a veteran who has a total disability permanent in nature resulting from a service-connected disability (does not apply outside of the States, Territories, and possessions of the United States, the District of Columbia, and the Commonwealth of Puerto Rico); or

(4) For any illness, injury or dental condition in the case of a veteran who is participating in a rehabilitation program under 38 U.S.C. ch. 31 and who is medically determined to be in need of hospital care or medical services for any of the reasons enumerated in § 17.47(i)(2); and

(b) In a medical emergency. Emergency treatment not previously authorized including medical services, professional services, ambulance services, ancillary care and medication (including a short course of medication related to and necessary for the treatment of the emergency condition that is provided directly to or prescribed for the patient for use after the emergency condition is stabilized and the patient is discharged) was rendered in a medical emergency of such nature that a prudent layperson would have reasonably expected that delay in seeking immediate medical attention would have been hazardous to life or health. This standard is met by an emergency medical condition manifesting itself by acute symptoms of sufficient severity (including severe pain) that a prudent layperson who possesses an average knowledge of health and medicine could reasonably expect the absence of immediate medical attention to result in placing the health of the individual in serious jeopardy, serious impairment to bodily functions, or serious dysfunction of any bodily organ or part. And,

(c) When Federal facilities are unavailable. VA or other Federal facilities that VA has an agreement with to furnish health care services for veterans were not feasibly available, and an attempt to use them beforehand or obtain prior VA authorization for the services required would not have been reasonable, sound, wise, or practicable, or treatment had been or would have been refused.