Last summer, school Principal Robert Hudak learned how to insert a tracheotomy tube into a child's windpipe and to replace the plug covering the inch-wide outer hole in the neck.

"We are on the alert during the day," he said. If the tube should happen to come out, "we would just shove it in, put the plug in and tie the ribbon in the back."

Hudak, principal of Ritchie Park Elementary School in Montgomery County, is one of the many educators throughout the Washington area who, faced with a shortage of school nurses and health aides, volunteers each year to take care of students with special medical needs and tend those with everyday injuries.

"I never thought I'd be doing this," said Hudak. Two secretaries and a teacher at Ritchie also learned to insert the tube and plug, using a plastic doll provided by the child's doctor. "Somebody has to do it," he said. "It might as well be me."

At 56 of the 100 elementary schools in Montgomery County, the principal, office secretary and parent volunteers are the sole providers of daily special and basic student health care, according to Claire Kownacki, director of the county's School Health Services Division.

"It may be the luck of the draw that we always have someone who is trained" in first aid, said Ed Shirley of the deputy superintendent's office at the Montgomery County schools.

Concern over the adequacy of a student health care system heavily dependent on volunteers prompted a two-year school survey recently completed by the Maryland State Department of Health and Mental Hygiene.

The findings, to be released to the State Board of Education on Nov. 28, will help the board determine whether to require each school to designate and train a health care backup.

The initial cost of such a program would be about $20 a child, or $16 million to $20 million at current enrollment levels in the state, said Polly Roberts, chief of the School Health Program at the Maryland State Department of Health and Mental Hygiene. It would include cardiopulmonary resuscitation (CPR) and first aid training for at least one adult at each school as well as for school bus drivers and field trip supervisors, she said.

The state study found great differences in health care delivery in the Maryland public schools, ranging from systems with no nurses to systems with a nurse in every school. The average situation, said Roberts, is one in which nurses are available for consultations and emergencies.

Since 1978, Roberts said, Montgomery County ranked "among the top" in the state in voluntarily complying with health standards that state officials issued, but which are not enforced or funded.

Although Washington area school systems report a high degree of volunteerism, they also vary widely in the professional health care available to students.

In Prince George's County, a nurse visits each of the 113 elementary schools about once a month and 82 percent of the schools have part-time health aides, while in the Alexandria school district there is a full- or part-time nurse at each of the system's 18 schools and no health aides.

The nurse-to-student ratio in the District is about 1 to 2,000 while in Fairfax, which relies on part-time health aides in its elementary schools, the ratio is 1 to 5,500, according to school officials.

In Arlington, which came under criticism from local PTAs last year, there are 22 new health aides -- one for each school -- this year.

In the District, health aides trained in basic first aid and CPR visit each of the 123 elementary schools two days every other week.

"We're on the low side" of health care staffing, said Mary Ellen Bradshaw, acting chief of the District's Bureau of School Health. "Everyone is somewhat concerned about it." The District has lost two of its 45 nurses since the 1982-83 school year.

Overall in Maryland, Roberts said, student health care has improved "dramatically" since 1976 when the state legislature discovered that less than half of its public schools had someone trained in first aid.

County and school system budget constraints and an influx of special education students needing extra attention forced everyday health care into the hands of volunteers as far back as a decade ago, say local school officials.

As a result, each year an army of principals and secretaries learns to give injections, dispense medication and treat scrapes and bruises. Schools constantly are trying to recruit parent volunteers as well.

At Ritchie Park elementary school, 10 parents volunteered this year to relieve the principal's secretary who, like most school secretaries, doubles as the health room aide. Each day they patch up an average of five to 20 playground scrapes and bruises, according to Principal Hudak. "It's not a glamorous kind of thing to sit in the office and wait for some bloody kid to come in," he said.

The situation at schools with handicapped students is somewhat different following two Supreme Court decisions requiring schools to provide enough medical care to special education students to allow them attend public schools. But there is still a need for volunteers.

At the H.W. Wheatley Center for handicapped students in Forestville, two teacher's aides volunteered this year to feed a 7-year-old mentally retarded mute student when the nurse is not present. The procedure requires them to inject a nutritional formula into a foot-long gastric tube that is inserted in a hole in his stomach.

"You get to know your child. You're able to feel your way with them and you begin to feel at ease with them," said Georgia Chester, one of two instructional aides at the Wheatley Center who volunteered to feed the student there. "When you see there is a special need, you just do it. I wanted to do this because I wanted him to go to school."

Of the more courageous volunteer training sessions held last year, the principal, two assistant principals and a school aide at Einstein Junior High School in Kensington injected saline solutions into each other to learn how to administer an antidote for a potentially fatal allergic reaction.

"We never had to use it, but it's nice to know you can do it," said Stuart Marder, assistant principal at the school.

More common than the emergencies is spending the day with one eye on the typewriter and the other on the adjoining health room full of students recovering from minor injuries and upset stomachs, said Susan Tayman, a secretary at Cashell Elementary School in Rockville. "Sometimes when you can tell a child is really hurt, I start to feeling a little upset," she said. "After a while you get kind of used to it."