Can a hot desktop cure a frozen medical network?

DOD uses thin clients to help revive health records system

Modern digital tools allow doctors to access patients’ medical records quickly while making rounds, greatly increasing the amount of diagnostic information available and the accuracy of their notes and treatment orders. 

At least that's the intention. The reality is that medical record applications are not always compatible with existing systems and workflows, which can lead to inefficiencies and rising overhead.

The Defense Department is trying to work through that problem by implementing virtual desktop technology. The system includes a suite of medical applications that users can access from any computer in a hospital, giving doctors and nurses quick access to patient records without needing to carry devices or go through a time-consuming log-in for every patient encounter.

Developed by a team at the Navy Space and Naval Warfare Lab’s Systems Center Atlantic, in Charleston, S.C., the Application Virtualization Hosting Environment (AVHE), is designed to give doctors rapid access to medical documents anywhere in a hospital without needing to reload a desktop PC.


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Cal Stephens, Spawar’s chief engineer for health systems, said the system replaces the thick-client model used at many DOD hospitals. One of the main difficulties doctors encounter in the existing systems is excessive boot times, which could take five or 10 minutes every time they moved to a new terminal during their rounds, he said.

Medical files, which are typically large, and new security protocols designed to protect them had contributed to rising network latency and made it difficult for clinical staff members to work efficiently, he said.

AVHE uses a hot desktop model that allows clinicians to log in once by using a Common Access Card smart card. After a virtual desktop boots, it automatically comes up every time a staff member swipes a CAC card to log in to a different machine. Sessions automatically time out and lock the machine after a staff member moves on.

Patrick Leitner, AVHE project engineer at Spawar, said the environment uses multiple technologies. The system is hosted on blade server hardware in the data center. It also uses a combination of VMware's VSPhere for the hypervisor and Citrix Systems' XenApp for the application presentation software.

Citirix XenApp servers are provisioned on demand with the Citrix Provisioning Server application. In use, the AVHE can support thousands of simultaneous users and provision hundreds of instances of the Citrix XenApp server. Each XenApp instance supports a small number of simultaneous users, Leitner added.

AVHE in the capital

AVHE is now being deployed to support a major new DOD medical facility being built in the Washington, D.C. area, the result of the consolidation of military health care facilities in the capital region called for by the 2005 Base Realignment and Closure Act.

For the national capital region effort, Spawar had to provide clinician access to DOD’s Clinical Desktop, a collection of applications developed by the Military Health System.

Perhaps the most important application in the suite is AHLTA, DOD’s electronic health records system that supports patient scheduling and access to electronic patient records.

One of the problems Spawar faced was a new version of AHLTA that increased the footprint of the client desktop PC. In addition, enhanced security settings degraded AHLTA’s network performance. That contributed to  excessive boot times, Stephens said.

“It wasn’t really efficient for doctors to go into the examination room,” he said. “They would use their CAC card to log into the computer. They would be sitting waiting for Windows to load — all the user files and stuff. So you’d be looking at five to 10 minutes for a doctor to get AHLTA up and running in an examination room to put data in or pull data out of AHLTA,” he said.

The Spawar team used AVHE to deliver AHLTA to users via a thin client. This solved the requirement for enhanced security on the end user device. Now AHLTA is delivered from a central server on a thin client, which significantly improves access performance, Stephens said.

The deployment also allowed the team to set up new features, such as the hot desktop environment, which loads doctors’ applications within seconds of logging in.

“They log in to AHLTA one time at the beginning of the day,” Stephens said. “When they pull their CAC out of the computer, it locks their session back in the data center. When they go into the next examination room and they put their card in, that session immediately resumes from its previous state. They can have AHLTA; it’s already open, already logged in, already available for them to go right in — enter the patient’s name and pull the record up.”

With AHTLA in a data center instead of a desktop PC, the team could add functionality to the virtual desktop, such as the Patient-Provider Context, which uses a protocol between applications to ensure that when a patient’s record is open in AHLTA, another application can pop up data related to that patient.

For example, if a doctor opens a patient’s AHTLA records on a monitor and accesses the Composite Healthcare System, an older system that AHTLA relies on, that patient’s name would automatically come up in the new application. “It’s a major time-saving capability for doctors,” Stephens said. “It also avoids the chance that the wrong patient’s record gets pulled up by a typo. It provides enhanced capability to make sure that the same person’s record is open in all the applications where it needs to be.”

The data center supporting the national capital region is a center point of DOD’s efforts to regionalize and consolidate health data centers, Stephens said. In most client/server applications, the client is usually in close proximity to the client. But the AVHE system completely decentralizes this model. “It doesn’t really matter where the application sits,” he said.

AVHE in North Chicago

While AVHE is just being deployed in the federal capital region, it has been successfully implemented at the James A. Lovell Federal Health Care Center in Chicago, where it supports DOD and Veterans Affairs Department doctors at a single facility. The combined DOD/VA Chicago facility is a critical element of efforts to make health information interoperable across the two departments.

In Chicago, AVHE hosts DOD’s AHLTA and VA’s Veterans Health Information System and Technology Architecture EHR system. In addition to providing the mobile hot desktop for doctors, it gives VA and DOD doctors access to records across departments.

Chicago is the first joint DOD/VA hospital, said Joe Brown, president of Accelera Solutions, which specializes in virtualization technologies and worked with Spawar to launch AVHE. The facility is designed so DOD doctors can treat VA patients and VA doctors can treat active DOD personnel. The goal is to provide a more holistic set of health services to military personnel.

“It provides a sort of seamless desktop between the two, which was one of the things we wanted — a DOD doctor and a VA doctor to have basically the same experience,” Leitner said.

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