In the four years she has worked for the Visiting Nurse Association Karen Egbert has noticed a change. The patients she sees are much sicker now, she says.

Egbert's experience in the Northeast Washington neighborhood she serves reflects a national trend. Hospitals today are sending patients home earlier -- and sicker -- than ever before. Pressure to hold down costs has led to "a real push" to discharge patients promptly, says Sandra Butcher, director of social services at George Washington University Medical Center.

At the same time, technological advances have made it possible for patients to receive services at home that previously would have required a hospital stay. Home care today may mean intravenous chemotherapy, respiratory support for a sick child, or the telemonitoring of an ailing heart.

Insurance companies like the change, because home care costs only about a third as much as hospital or nursing home care. Patients like it, because they are more comfortable in their own homes. Even doctors, after initial reservations, are warming to it.

For the home care industry, the trend toward earlier hospital discharge, combined with the aging of the population, has meant a bonanza. Predicasts Research Group, a Cleveland-based market research firm, recently projected that revenues from home health services will increase from $3.3 billion in 1983 to $14.2 billion in 1995.

The bulk of the home care case load is still carried by voluntary agencies, particularly the Visiting Nurse Associations. The Washington VNA, which celebrates its 85th anniversary this year, makes 200,000 home visits a year, two thirds of them in the District and the rest equally divided between Montgomery and Prince George's counties. Across the river, the Visiting Nurse Association of Northern Virginia makes 54,000 visits a year.

But the past five years has seen a proliferation of proprietary agencies -- those in business to make a profit.

For-profit agencies, including some of the national chains, have been on the local scene for years. Upjohn HealthCare Services, for example, entered the Washington-area market 15 years ago.

But it was only in the late 1970s that changes in federal law made it possible for proprietary home care agencies to obtain Medicare certification and thus get federal payment for the elderly patients who make up a large part of a home health agency's case load.

The number of Medicare certified proprietary agencies shot up 273 percent between 1980 and the end of 1983, reports the National Association for Home Care, an industry group.

The most recent surge in new home health services has come from hospitals. Modern Healthcare magazine reported in December that 65 percent of hospitals it recently surveyed expect to be providing home health care services by mid-1985 -- a big jump from 1983, when only 25 percent offered these services.

"Hospitals are developing home care in response to the market," said Butcher. George Washington launched a for-profit home care agency last April, in a joint venture with Care Corporation of Grand Rapids, Mich.

The new Medicare prospective payment system makes the provision of home care particularly attractive to hospitals.

Under prospective payment, Medicare pays a flat rate for in-hospital treatment of a particular illness, no matter how much or how little care the patient requires. The new system is a powerful incentive for a hospital to get a patient well and home as quickly and efficiently as possible.

If a hospital has a home care service, it may be able to discharge a patient earlier than it otherwise would. It then stands to make additional income from providing home care, which is not yet under prospective payment.

Technological improvements have made great changes in the kind of care available in the home. The developments have launched a new industry, as pharmaceutical companies and distributors of medical supplies have leaped to meet the need for what has come to be called "high-tech" home health care.

One local contender in this new market is TeamCare, a 1-year-old company headed by Rockville pharmacist William Hawk, which provides intravenous therapy to patients at home or in nursing homes.

Two fairly recent inventions have made Hawk's business possible: the i.v. infusion pump (sometimes controlled by a microprocessor) that can regulate the delivery of intravenous fluids; and the implantable catheter, a tube that can be inserted in a major blood vessel and left in place to allow easy access from outside the body. In combination, these two devices allow do-it-yourself i.v. therapy.

TeamCare's services include chemotherapy, antibiotic therapy and total parenteral nutrition (feeding nutrients directly into the bloodstream) -- all treatments that would have required a hospital stay five years ago.

If a patient is bedridden, TeamCare will work with a home health care agency, Hawk said, often training the agency staff in the use of the specialized equipment. If a patient is able to care for himself, TeamCare staff will instruct the patient.

Some out-of-state high-tech firms have opened offices in the metropolitan area. But Abbott Laboratories, one of the nation's largest pharmaceutical companies, operates from its Chicago home base, with only a minimal field staff.

Abbott provides parenteral and enteral (to the intestine) nutrition, chemotherapy and antibiotic therapy. The firm employs a nurse, who goes to homes to train patients, said Glenna Langley, a registered nurse who is Abbott's local sales representative.

The usual caseload is about 20 patients, she said, and there is constant turnover. A typical course of treatment lasts six weeks, and some out-of-town patients -- discharged from the big research hospitals -- go home to complete their therapy after Abbott's nurse has trained them, Langley said.

For patients who run into problems, Abbott provides a 24-hour hotline to Chicago. This is answered by a nurse clinician who has access by computer to complete information on Abbott's patients, including the phone numbers of their local emergency services.

Like all home health care, high-tech services must be prescribed and supervised by a physician. But some traditional home health agencies, particularly the smaller proprietary agencies, are uncomfortable with the sort of self care that TeamCare and Abbott provide.

They cite aggressive sales campaigns by out-of-state companies and complain that a quirk in the Medicare rules allows the high-tech providers to escape most of the federal red tape that bedevils the nursing agencies.

Robin Driscoll, executive director of the Maryland Association of Home Health Agencies, called high tech "a very hot issue." She said the high-tech companies are doing a variety of things that fall into the category of skilled nursing, even though they are not subject to the same regulation as nursing agencies.

JoAnne Bayles, director of Holy Cross Hospital's home care program, had cautious praise for the work of the high-tech firms. "The supply companies often do a very good job," she said. "They do what they do very well." But Bayles said she thinks the patient is best served by a combined effort -- a high-tech company and a home health agency working together.