NEBEKER, Associate Judge:
Although these two cases arose from the same occurrence they were tried and were appealed separately. They are here consolidated for disposition. As each defendant raises different issues on appeal, we meet the concerns of each in sequence.
APPELLANT PARKER
Following a jury trial, the defendant was adjudged guilty of murder in the second degree under D.C.Code 1973, § 22-2401. He seeks a new trial on the ground that the trial judge failed to instruct the jury (1) that, if it concluded that a doctor’s termination of the victim’s life support system constituted willful or intentional malpractice or was an “abnormal” response to the victim’s condition, it should find the defendant not guilty; and (2) that, if it found that the victim would have lived for more than a year and a day but for the termination of the life support system, it should find the defendant not guilty. We affirm.
I
On January 13, 1976, the appellant and three others attempted to snatch a purse from an 85-year-old woman. When the appellant latched onto the purse, the victim recoiled, whereupon she was struck from behind by one of the appellant’s companions. The blow caused the victim to fall forward to the sidewalk. The band fled without the purse. A bystander found the injured woman conscious and able to talk. By the time the police arrived, she was unable to respond and an ambulance carried her to a hospital. There she was administered to by a resident and thereafter by a neurosurgeon. Upon arrival at the hospital the victim was able to talk. Her condition, however, quickly degenerated to where she could neither speak nor respond to verbal commands. After 24 hours in the hospital, she exhibited only primitive reflexes to stimuli. She failed to improve. Six days later, on January 19, on the basis of the patient’s condition and her age, after consultation with other physicians involved in the case and upon agreement by the victim’s son, the neurosurgeon discontinued all [1279]*1279“heroic measures.” 1 The woman died fifteen to twenty minutes later.
II
The trial judge properly refused to instruct the jury on the defense’s theory that discontinuing the “heroic measures” may have constituted an “intervening cause” of death2 so as to insulate the defendant from homicide liability. Although no specific instruction was requested,3 the defendant suggests in his brief that the court could have properly instructed the jury as follows:
If you find that the Government has proved beyond a reasonable doubt all the other elements of the offense and that the defendant caused [the victim’s] death, it is your duty to find the defendant guilty of murder. If, on the other hand, you find that the Government has failed to prove beyond a reasonable doubt that the defendant caused [the victim’s] death because the actions of [the physician] constituted intentional or willful malpractice or were an abnormal response to the situation caused by the defendant’s acts, then you must find the defendant not guilty of murder. [Emphasis added.]
For such an instruction to have been proper, evidence must have been presented (1) to resolve the issue of what constitutes “in[1280]*1280tentional or willful malpractice” or an “abnormal response,” and (2) to demonstrate that the actions of the attending physician breached that standard. E. g., Haven v. Randolph, 161 U.S.App.D.C. 150, 152, 494 F.2d 1069, 1070 (1974) (per curiam) (prima facie case established by evidence of standard and breach).4 In this case, there is no evidentiary basis for the kind of instruction now proposed.
[1279]*1279[m]easures that are other than normal supportive care. For example normal supportive care would be assuring that the patient has food to eat, that they have clothing to keep them warm, to prevent pneumonia. What I consider heroic in this case was infusions of drugs in order to reduce the pressure in the head, maintenance of the patient on a machine, when there was no obvious response to those measures of therapy in the sense of improvement in the patient’s condition.
[1280]*1280The situation is analogous to a tort claim for medical malpractice. With one exception, a jury is permitted to find a physician liable in tort for malpractice only when the standard of care has been established by expert testimony. E. g., Harris v. Cafritz Memorial Hospital, D.C.App., 364 A.2d 135 (1976); Robbins v. Footer, 179 U.S.App.D.C. 389, 392-93, 553 F.2d 123, 126-27 (1977). The exception to the rule is:
Where laymen can say, as a matter of common knowledge and observation, that the type of harm would not ordinarily occur in the absence of negligence, the jury is allowed to infer negligence without expert testimony being presented. Haven v. Randolph, 161 U.S.App.D.C. 150, 151, 494 F.2d 1069, 1070 (1974); Prosser, The Law of Torts . . . 227. [Harris v. Cafritz Memorial Hospital, supra at 137 (emphasis added) (footnote omitted).]
See People v. Love, 45 Ill.App.3d 259, 3 Ill.Dec. 874, 876, 359 N.E.2d 733 (1977) (“where the evidence of causation is beyond the understanding of laymen, expert testimony must establish . . . the [cause of] death”), rev’d, 71 Ill.2d 74, 15 Ill.Dec. 628, 373 N.E.2d 1312 (1978) (evidence of causation sufficient without further expert medical testimony); State v. Brandt, 467 S.W.2d 948 (Mo.1971) (expert unnecessary where, from evidence, reasonable persons “of average intelligence would know from [their] own experience or knowledge that the wound was mortal in character,” but expert testimony is necessary “where the cause of death is obscure and an average layman could have no well grounded opinion as to cause”); see also D. C. v. Barriteau, D.C.App., 399 A.2d 563 (1979) (expert testimony regarding economic loss). We will examine first the facts as they apply to the exception and then as they apply to the rule.
The medical conduct here involved does not, “as a matter of common knowledge and observation,” constitute the requisite malpractice. The exception applies only where “a physician has committed a blunder so egregious that a layman is capable of comprehending its enormity. An example is the case of a surgeon who leaves a sponge in an incision after the removal of a kidney.” Haven v. Randolph, supra 161 U.S.App.D.C. at 152, 494 F.2d at 1070, citing Rodgers v. Lawson, 83 U.S.App.D.C. 281, 284-85, 170 F.2d 157, 160-61 (1948). On facts quite similar to those here, however, an Illinois intermediate appellate court recently ruled that a physician’s discontinuance of heroic measures was “reasonable” medical care.
Defendant’s contention that the evidence failed to prove beyond a reasonable doubt that the victim died of the wounds from the gunshot is without merit. When the victim was brought to the hospital, his pulse was minimal. The neurosurgeon who examined him testified that the bullet had damaged a major portion of his brain and that he then exhibited many signs of death. The doctor’s decision to withdraw life support measures was rea[1281]*1281sonable. [People v. Olson, 60 Ill.App.3d 535, 538, 18 Ill.Dec. 218, 222, 377 N.E.2d 371, 374-75 (1978).]
We need not hold that the doctor’s actions were reasonable because that issue is not before us. It appears clear, however, that they were not so unreasonable, as a matter of common knowledge, as to be grossly negligent or worse.
The legal and medical authorities, cited in the briefs, confirm the conclusion that the facts here do not fall within the exception to the requirement of expert testimony. The government, on one hand, cites authorities to support the proposition that the neurosurgeon’s action was reasonable as a matter of law. The defense, on the other hand, quotes from authorities holding the position that it is per se unreasonable for doctors, after consulting with a patient’s family, to discontinue artificial life support measures. The lack of consensus among the cited authorities undermines the conclusion that the physician’s actions here constituted gross malpractice as a matter of common knowledge.
Consideration of a series of articles in the New England Journal of Medicine also leads to this conclusion. In one article, the Critical Care Committee of the Massachusetts General Hospital reported on the “Optimum Care for Hopelessly Ill Patients.” 295 New Eng.J.Med. 362 (1976). The Committee recommended to the hospital the use of a system by which critically ill patients are placed in one of four classes as follows:
1. Whenever appropriate, critically ill patients should be classified according to the following system.
Class A Maximal therapeutic effort without reservation.
Class B Maximal therapeutic effort without reservation but with daily evaluation because probability of survival is questionable.
Class C Selective limitation of therapeutic measures. The criterion which determines every aspect of the therapeutic regimen continues to be the overall welfare of the patient. At this time certain procedures may cease to be justifiable and become contraindicated. Particular attention must be given to resuscitation measures of all kinds. The therapeutic plan must be clearly detailed to the other members of the care team so that all understand and are united about their caring efforts and responsibilities. As an integral part of caring for the patient, approximate notes specifically describing the therapeutic plan should be made in the patient’s record. The patient’s resuscitation status should be similarly recorded in conformance with the policy governing orders limiting full cardiopulmonary resuscitation.
A Class C Patient is not an appropriate candidate for admission to an Intensive Care Unit. A decision to transfer the patient out of the Intensive Care Unit is based upon the needs of the patient, and transfer is appropriate only after required comfort measures become manageable in a nonintensive care setting. Whatever the patient’s location, however, and irrespective of the specific therapeutic measures that have been selectively limited, a Class C patient and his family require and must be given full general support.
Class D All therapy can be discontinued. Any measures which are indicated to insure maximum comfort of the patient may be continued or instituted.
According to the Committee, “[although Class C designation implies that death is the probable outcome, it may not necessarily be the case. With improvement, the patient’s category may be changed to a more optimistic one.” Id. at 363. As to Class D patients, the Committee writes:
The definite act of commission, such as turning off a mechanical ventilator, is to be performed only by an appropriate physician after consultation with and concurrence of the family and appropriate hospital committee (or committees) where indicated. Assignment to Class D is generally reserved for patients with brain death, or when there is no reasonable possibility that the patient will return to [1282]*1282a cognitive and sapient life. [Id. (emphasis added).]
The committee’s recommendation aligns with our determination that the neurosurgeon’s disconnecting the respirator did not, as a matter of common knowledge, constitute gross negligence or an abnormal response to the patient’s situation. The neurosurgeon testified at trial that the victim could never return to a cognitive and sapient life. He also consulted with and received the concurrence of the victim’s family, which practice corresponds to the Committee’s recommendation. Thus, the exception to the general requirement, that expert testimony is required to establish a standard by which a jury may determine malpractice or intentional malpractice, is not available here.
Mr. Parker confesses the propriety of terminating heroic measures for a person when a court-appointed guardian requests termination, see, e. g., In re Quinlan, 70 N.J. 10, 355 A.2d 647 (1976), but states that without court intervention, the action is never reasonable. We reject that argument. No legal authority is cited or appears to exist that requires the courts to intervene when extraordinary life support methods are threatened with withdrawal pursuant to a so called “living will” or as done here. See, e. g., In re Dinnerstein, — Mass.App. —, 380 N.E.2d 134 (1978) (decision not to resuscitate not for the judiciary, but one “peculiarly within the competence of the medical profession”; “validity of order [not to resuscitate] does not depend on prior judicial approval”). The attending physicians and the family of the victim owe no duty to the defendant to treat the victim so as to mitigate the defendant’s criminal liability. The defendant’s desire to mitigate his liability may never legally override, in whole, or in part, the decisions of the physicians and the family regarding the treatment of the victim.
Turning now to the general rule that expert testimony is necessary to establish malpractice, (here, willful and intentional malpractice5), a review of the expert testimony at trial discloses no standard against which the jury could have determined that the neurosurgeon committed malpractice. The defense had the obligation to attempt to establish the standard by its own experts or by the government’s experts. In this case, it attempted the latter. The government’s experts, however, never intimated that the termination of heroic measures amounted to malpractice, much less willful or intentional malpractice. Indeed, it appears from the record that no expert testified concerning intentional or willful malpractice. At page two of its reply brief, appellant attempted to refute this line of logic:
Appellee seems to suggest that appellant would only have been entitled to the requested instruction had he introduced expert evidence at trial attacking Dr. Dennis’ actions and furthermore that appellant was citing medical and legal authorities in his appellate brief in a vain attempt to supply the evidentiary basis for the requested instruction which was lacking at trial. (Brief for Appellee, at p. 24). To the contrary, these authorities were cited solely to demonstrate that on the basis of the evidence presented by the government at appellant’s trial, and with nothing more, the jury could reasonably have found that Dr. Dennis’ actions were a superseding cause and therefore appellant was entitled to an instruction on this issue. [Emphasis added.]
The defense thus contends, contrary to law as explained above, that no testimony, other than the facts of the physician’s action of disconnecting the respirator, would have been necessary to support a verdict based on “superseding cause.” Implicit in this argument is the concession that no expert testimony went to establish that the terminating action was anything but reasonable. Consequently, there being no evidentiary predicate for the instruction now proposed, [1283]*1283we are unable to conclude that error warranting reversal has been demonstrated. See Wright v. State, Del., 374 A.2d 824, 829 (1977) (expert testimony generally required in homicide prosecution for causation defense based on unskilled treatment by attending physician).
III
The trial court did not err in failing to instruct the jury as follows:
If you find that with medical care [the victim] would have survived a year and a day, then you may not find him guilty of murder. But if you don’t find that she wouldn’t [sic] survive for a year and a day, then you may.
The year and a day rule is in force in the District of Columbia, having been adopted under D.C.Code 1973, § 49-301, from the common law. See State v. Brown, 21 Md.App. 91, 318 A.2d 257 (Ct.Spec.App.1974) (year and a day rule, as part of the common law of England, adopted by Maryland in 1776; see also Louisville, Evansville and St. Louis R.R. v. Clarke, 152 U.S. 230, 239, 14 S.Ct. 579, 581, 38 L.Ed. 422 (1894) (year and a day rule is in force “in this country” unless statutorily modified). Although the rule has been variously stated, it is essentially that “no person should be adjudged ‘by any act whatever to kill another who does not die by it within a year and a day thereafter.’ ” Id. Although this rule is a part of the law of the District, it does not absolve the appellant from liability for murder on the record before us because (1) the victim died within a year and a day of the assault and robbery and (2) there was no evidence upon which a reasonable juror could have concluded that the victim would have lived for a year and a day.
The rule provides for a time beyond which, the courts at common law determined, the prosecution could not, as a matter of law, prove that the unlawful act caused the victim’s death. Id., quoting 3 Coke, Inst. 53. Under the rule, if the victim expires after the designated time, the defendant is not required to show that the death ensued from something other than his act. His misdeed is per se excluded from the possible causes of death. By its terms and its purpose, however, the rule is inapplicable where the victim dies within a year. Where, as in this case, the victim dies within a year, the defendant may be entitled to an intervening cause instruction, but the time period of a year and a day, and the year and a day rule would be improper subjects of instruction. See Hopkins v. United States, 4 App.D.C. 430, 439 (1894) (year and a day rule does not absolve one from liability for “homicide or murder” if death occurs within a year and a day, although proper treatment may have prolonged life beyond that time). Therefore, because the appellant’s victim died within a year and a day of the infliction of the wound, this case is without the ambit of the rule, and no reversal is warranted.
The appellant is not prejudiced here by a misunderstanding of the law because, on the record, there was no evidence that the victim would have lived for a year and a day. The only relevant testimony, which the defense attorney elicited from the neurosurgeon and which appears to be disposi-tive of the defense’s contention, is set forth below.6 The defendant points to the itali[1284]*1284cized portion as the sole testimony regarding the rule because only it refers explicitly to the year and a day time period. We do not read it so narrowly. No reasonable juror could have concluded, on the basis of this testimony, that the victim would probably have survived for a year and a day.
IV
Our holding in this case is limited. We neither endorse nor condemn the neurosurgeon’s actions. No mention has been made of the legal definition of “death” in the District of Columbia. As a matter of law, according to the evidence presented at trial, the defendant was not insulated from homicide culpability. The defendant’s conviction is
Affirmed.
APPELLANT J.N.
The appellant has been convicted of attempted robbery under D.C.Code 1973, § 22-2902, and of felony murder under D.C. Code 1973, § 22-2401. He seeks reversal of both convictions because his confession, which was used at trial, was unconstitutionally elicited. As an additional reason for reversing his murder conviction, he states that the actions of the physician attending the victim constituted an “intervening cause” that insulates him from liability for murder as a matter of law.7 We affirm. [1285]*1285The facts will be set forth in conjunction with the discussion of the issue to which they relate.
The appellant’s confession was not, as a matter of law, unconstitutionally elicited. The defendant admits in his brief that he was advised of his Miranda rights on “several occasions.” He nevertheless contends that, because of his young age (12 years) and other factors,8 his confession was educed without a voluntary, knowing and intelligent waiver of his rights. We are of the opinion, however, that the instant record and the pertinent case law lay to rest the appellant’s contention.
Examining the record under the “totality of the circumstances” test, see In re F.D.P., D.C.App., 352 A.2d 378, 380 (1976), we find that the evidence supports the factual determination that the appellant waived his rights. Although the appellant was only 12 years old, he had been previously arrested for felonies on two separate occasions. Police officers testified that, on each of these previous encounters with the criminal justice system, the appellant was advised of his Miranda rights and had chosen to waive those rights. See In re T.T.T., D.C.App., 365 A.2d 366, 369 (1976) (juvenile’s familiarity with the criminal justice system weighed in determining voluntariness). That the appellant was not accompanied by his guardian9 is a factor to be weighed, but is not itself dispositive of the voluntariness issue. In re J.F.T., D.C.App., 320 A.2d 322, 324 (1974) (rejection of rule that juvenile’s statement made in absence of parent or counsel is per se involuntary). The appellant, while complaining that his guardian did not accompany him, states that a factor going to show that the waiver of his rights was not voluntary is the admonishment by his grandmother-guardian, prior to the arrival of the police, that he confess. At the suppression hearing the appellant testified that no one forced him to confess and that he did so only because his grandmother told him to tell the police what happened.
The custodial and examining officers exercised great care in explaining to the appellant his rights in such a manner that the appellant would understand them. First, they explained relatively difficult words, such as “attorney,” to assure that the appellant understood his rights. Second, they repeatedly informed him of his rights. Indeed, one might say they appeared to be encouraging him to refuse to speak. The appellant admits in his brief to having been informed of his rights on “several occasions.” Police officers testified to informing him on six occasions. Third, the officers had the appellant tell them in his own words what he understood his rights to be. His response further confirms that he appreciated his rights and chose to waive them.
On this record, we find no error in not suppressing the appellant’s confession. Consequently, we turn to the issue of “intervening cause.”
The facts relevant to the “intervening cause” issue are essentially those of Parker v. United States, decided instanter. While attempting to snatch a purse from an [1286]*1286elderly woman, the appellant and some of his friends fractured their victim’s skull and further injured her head, including her brain. As her condition deteriorated, she was placed on a respirator and about a week later, following a determination of irreversible brain damage and a discussion with the victim’s family, all extraordinary measures, including support from the respirator, were discontinued. The victim died shortly thereafter. The appellant, unlike his companion Parker, touched neither the victim nor her purse. Whereas in Parker the issue presented was whether there was any evidence to support a specific suggested intervening cause instruction, we here face the issue of whether the appellant is insulated from liability for murder as a matter of law, the appellant having been tried without a jury. Despite these differences, Parker mandates that we reject this contention because there was no expert testimony at trial to support a finding that the attending physician acted inappropriately in disconnecting the life support system.
The success of the appellant’s defense of “intervening cause” hinges on his demonstrating that the act, for the commission of which he stands convicted of homicide, was not a “substantial factor” contributing to the victim’s death. He attempts the demonstration by defining two forces or acts that impacted upon the deceased. The first act was his, the second was not. It is incumbent on him to establish that the law regards the acts as distinct from one another. See, e. g., Hamilton v. United States, 102 U.S.App.D.C. 298, 252 F.2d 862 (1958) (where victim had been rendered unconscious by defendant’s blow and had then been left in roadway where she was run over by a taxi, defendant liable for death). If the acts are not separate, the perpetrator of the first is held responsible for the consequences of the second and the appellant’s defense fails. Id. If the acts are distinct, the law will not punish him except for the first act. E. g., Hopkins v. United States, supra at 440. Once the acts are determined to be separate, a second issue arises: whether the first act, standing alone, was a substantial factor contributing to the death.10 If it was, then liability will attach.11 An adverse resolution of either of the two issues will lay the defense to rest. While the issues are listed in sequence, they may be resolved also in the reverse order.
Concerning the first issue, whether the law regards the two acts as separate, we hold that the record does not support a conclusion that the acts were separate as a matter of law. The appellant defines the first act as that which resulted in the injury to the victim’s head. The discontinuance of extraordinary measures constitutes the second. The second act was performed by medical personnel acting in their role as such. Where the action of such medical personnel is either reasonable or negligent, the law holds the perpetrator of the first act liable also for the consequences of the second. For the law to deem the acts separate, the second act must descend at least below the negligence level.12 Testimony, establishing that medical treatment is so egregious so as to fall within the category, may generally be elicited only from experts. Parker v. United States, supra. We hold that, on the record in this case, the trial judge could reasonably have concluded that the second act was a reasonable medical procedure because the sole expert testified to this effect.
[1287]*1287As the appellant has failed to overcome the hurdle of the first issue, the second issue, of whether the first act alone constituted a substantial factor in causing the victim’s death, does not arise. The conviction is