An estimated 58 percent of the 270 infant deaths in the District of Columbia in 1977 could have been prevented with high-quality medical care, according to an unpublished study by the city's health planning agency.

Washington has the highest infant mortality rate of any major city in the nation, a rate that has remained constant for about a decade, while infant death rates in most other cities have dropped.

In 1977, the District had an infant mortality rate of 27.5 deaths per 1,000 live births, compared to a national rate of 14 per 1,000.

The D.C. health planning agency concluded that deaths due to infectious and parasitic diseases, flu and pneumonia and intestinal obstructions were preventable. In addition, the study said that 75 percent of the deaths attributed to such causes as birth injuries, asphyxia and immaturity were preventable.

The planners have stressed that these are estimates and say that if one were to review the case records of those infants who died some of the deaths listed as preventable might not have been.

The health planners have made it clear that they are not talking about 21st century technological gadgetry when they speak of the current ability to save these childrens' lives. Instead, they say that by applying the kind of high-quality care some city residents already receive before, during and after birth, the rate could be drastically reduced.

Dr. John Scanlon, director of neonatology -- the care of infants from birth to 28 days -- at Columbia Hospital for Women, contends that the infant mortality rate in the city could be reduced about 20 percent in one year simply by teaching delivery room teams in every hospital the proper technique for resuscitation infants suffering from asphyxia -- unconsciousness due to lack of oxygen.

By reducing asphyxia, Scanlon contends, other causes of death, and lifelong problems such as brain damage, could also be reduced.

The percentage of preventable deaths is increased from 58 to 61 if poisoning and accidental deaths are included. Health planners contend these deaths can be eliminated through parent education and outreach programs.

City health officials have long contended that the infant mortality rate is high because of the large number of poor blacks in Washington. Detroit, Newark, Cleveland and New York have nonwhite infant mortality rates lower than Washington's 29 deaths per 1,000 births.

Mayor Marion Barry has called infant mortality the city's number one health problem, and a hurriedly produced plan to reduce the number of infant deaths predicts that the job can be done for only about $580.000.

The estimates on preventable deaths were prepared as part of a ward-by-ward study of infant mortality in 1977 and were included as an appendix in the plan to reduce infant mortality. The estimates were deleted from the appendix by the committee preparing the report.

Department of Human Resources Director Albert P. Russo said last night that he was told by city health director D. Raymond Standard that the estimates were taken out of the appendix because there was no time to confirm the findings and because "every effort was made in developing the action plan to eliminate a mass of statistical data."

That plan, prepared by DHR, calls for, among other things:

A massive outreach and media campaign to encourage pregnant women to seek proper prenatal care in city or private facilities.

The establishment of a computer link between D.C. General Hospital and the city's public health clinics, to allow the exchange of medical records of pregnant women.

The expansion of the city's program to provide pregnant women with supplemental foods.

The development of a sophisticated system to ensure the transport to specialty hospitals of sick newborns.

Most of the major items called for in the plan are facilities or programs the city has been repeatedly criticized in the media and in medical circles for not having.

Dr. Frederick Green, chairman of a committee appointed by Barry to implement the infant mortality plan, said yesterday that even under the best of circumstances some infants will die of causes in the preventable categories.

"We have some deaths here," said Green, associate director of Children's Hospital National Medical Center, "where the parents don't bring the children in until it's simply too late."

Sheila Joroff, director of the State Health Planning Agency, said the health planners, beyond estimating the number of preventable deaths, determined that the city would have had an infant mortality rate between 11 and 12 deaths per 1,000 births had those children lived.