Doctors who treated 16-year-old Rita McDowell at D.C. General Hospital were consistently defended by a deputy city medical examiner yesterday who said that the medical decisions they made were vital to the proper treatment of a critically ill patient.

Dr. William J. Brownlee, the official, told a D.C. Superior Court jury that the intern and resident who attended McDowell in the hospital's intensive care unit would have been remiss if they had not made repeated attempts to reinsert an intravenous line needed to monitor McDowell blood circulation.

Brownlee, a government witness at the second degree murder and perjury trial of former Washington abortionist Dr. J. Sherman, disputed defense contentions that McDowell's death resulted from fluid that accumulated in her chest cavity as a result of the punctures.

He testified that in his opinion McDowell's death was caused by shock and blood poisoning due to an infection that followed an abortion. McDowell, a 10th grade high school student, died at D.C. General on March 8, 1975, four days after she went to Sherman's clinic in Northwest Washington for an abortion.

During lengthy cross-examination by defense attorney Robert F. Muse, Brownlee acknowledged that the intern's repeated attempts to reinsert the line had failed. But, he testified "I wouldn't hold that against him."

Brownlee, again questioned by Muse, insisted that, in his opinion, both the intern and resident were capable of managing McDowell's condition.

Muse also attempted to establish that McDowell could have suffered infection as a result of pre-existing bacteria that passed into her bloodstream during a miscarraige. Brownlee testified that was "possible" but later told the jury that a woman's natural bodily defense mechanisms would normally prevent such an occurrence.

During yesterday's court session before Judge Fred B. Ugast, a former receptionist at Sherman's clinic testified that she lied under oath, at Sherman's direction, about conditions at his abortion clinic.

Mary Farr, who lives in Forestville, MD., also testified that she helped Sherman rewrite appointment books and recreate McDowell's medical records after McDowell's death. Earlier in the trial, two other former employees also testified they had lied at Sherman's direction. Farr is expected to continue her testimony today.