I've read the exchange with Dr. Makey several times.
I conclude that there was no disagreement about the
hopelessness of the 2008 patient's prognosis, but that
Dr. Mackey felt slighted and hurt because he had 
no opportunity to reconcile himself to the patient's
impending demise. Obviously not only the patient
himself, the patient's family, but also the patient's
physician/surgeon needs time for reconciliation with
the inevitable. As he wrote quite eloquently, Dr. Mackey
considered himself responsible for the patient's fate.
The organizational circumstances in the hospital made
it impossible for him to discharge that responsibility;
you were on service, you had been made responsible,
and accordingly you became the object of Dr. Mackey's
understandable chagrin and resentment. It's obvious
that he hasn't forgotten.

In the 2008 case, Dr. Mackey's complaint against the
organization that deprived him of the involvement
with the patient's demise, so it seems to me, had some
justification; as distinct from his complaint against
you who had been made responsible for the patient's
current hospitalization.  A complaint against you was
unjustified.

In the 2009 case, Dr. Mackey is clearly in error. There
is no arguable reason why the 2009 patient should not have
been hospitalized, assuming that hospitalization would not
have entailed any economic sacrifice for her or her family.
(After reading the correspondence, my understanding of Dr.
Mackey has changed: he's not as inarticulate as I had assumed.)
I'm uncertain whether you should take it upon yourself to
tell the general surgical and gyn services whom they should
or should not admit; perhaps it's in the hospital's interest
that you should weigh in on this issue. But surely you mustn't
permit Dr. Mackey to prescribe whom the medical service should
or should not admit by stigmatizing the 2009 patient as 
a "social admission". "Social admission" are fighting words,
because the insurers and Medicare won't pay for them. The
defense against "social admission" is "risk management".
The 2009 patient might well have developed (delayed)
peritonitis, even though the white count was still normal
and the temperature not yet elevated, - that must be at least one
of your arguments, and had she in fact developed (delayed)
peritonitis, the refusal of admitting physicians to comply
with the Emergency Room decision that she be admitted,
would have constituted legally indefensible malpractice.
Prepare yourself for your conference with Dr Mackey by
looking up peritonitis incubation periods for the various
pathogens to which the temporarily externalized intestines
might have been exposed. The incubation period of fungi is
measured not in days, but in weeks or months.