A retrospective analysis of a pediatric tele-echocardiography service to treat,triage,and reduce trans-Pacific transport

Abstract

Introduction

Tele-echocardiography can ensure prompt diagnosis and prevent the unnecessary transport of infants without critical congenital heart disease, particularly at isolated locations lacking access to tertiary care medical centers.

Methods

We retrospectively reviewed all infants who underwent tele-echocardiography at a remote 16-bed level IIIB NICU from June 2005 to March 2014. Tele-echocardiograms were completed by cardiac sonographers in Okinawa, Japan, and transmitted asynchronously for review by pediatric cardiologists in Hawaii.

Results

During the study period 100 infants received 192 tele-echocardiograms: 46% of infants had tele-echocardiograms completed for suspected patent ductus arteriosus, 28% for suspected congenital heart disease, 12% for possible congenital heart disease in the setting of likely pulmonary hypertension, and 10% for possible congenital heart disease in the setting of other congenital anomalies. Of these, 17 patients were aeromedically evacuated for cardiac reasons; 12 patients were transported to Hawaii, while five patients with complex heart disease were transported directly to the United States mainland for interventional cardiac capabilities not available in Hawaii.

Discussion

This study demonstrates the use of tele-echocardiography to guide treatment, reduce long and potentially risky trans-Pacific transports, and triage transports to destination centers with the most appropriate cardiac capabilities.

Keywords

Transport ECMO congenital heart disease telemedicine tele-echocardiography

Introduction

Congenital heart disease is the most common birth defect, with an incidence of roughly 1% of live births.¹ It is oftentimes a challenge for the medical provider to clinically differentiate heart disease from respiratory disease in the distressed newborn. While many medical centers have pediatric cardiologists on staff to perform echocardiograms, the gold standard for non-invasive cardiac imaging and diagnosis, many community and rural hospitals with delivery services do not have a timely way to accurately diagnose cardiac disease after birth.² As a result, when a cardiac diagnosis is in question, infants are often transferred. These air or ground transports can result in unnecessary risk and increased cost, particularly if no or benign heart disease is found after transfer.

Telemedicine has been described as an ideal way to address disparities in access to care.³ One telemedicine technology in particular, tele-echocardiography, has been shown to decrease length of hospital stay, decrease costs, prevent unnecessary transports, increase patient satisfaction, and increase quality of care.⁴ In this model, echocardiograms are conducted by cardiac sonographers at outlying hospitals. The echocardiogram is either observed in real time by a pediatric cardiologist via a videoconferencing system, or the data is transmitted by a store-and-forward technology to be read in the future.

The first report of echocardiographic transmission by telephone was published in 1989, with subsequent improvements in image quality, speed, and bandwidth over the next two decades with the use of multiple Integrated Services Digital Network (ISDN) or T-1 lines.^5-8 With the recent introduction of internet-based file transmission, most tele-echocardiography services have moved to web-based viewing systems.^4,9,10

This study describes our 10-year experience using tele-echocardiography to evaluate neonates at United States Naval Hospital Okinawa (USNHO), Japan, in conjunction with the pediatric cardiology service at Tripler Army Medical Center (TAMC), Hawaii. Although USNHO hosts a 16-bed, level IIIB neonatal intensive care unit (NICU) and is the neonatal transport hub for the Department of Defense in the Western Pacific, it has limited and sometimes no access to host-nation pediatric cardiology consultation services. In order to transfer an infant to the nearest US pediatric cardiology service, the patient must be transported on an 8-hour flight to TAMC, Hawaii. This study demonstrates how tele-echocardiography allows USNHO and TAMC to efficiently diagnose neonates, ensure correct treatment, avoid unnecessary transport, and triage transport to the correct tertiary care facility. In addition, if urgent cardiac management or surgery was required, tele-echocardiography facilitated triaging the transport to a medical center with the necessary interventional cardiac capabilities.

Methods

We retrospectively reviewed all infants who underwent tele-echocardiography at a remote 16-bed level IIIB NICU from June 2005 to March 2014. Echocardiograms were completed using a Philips 5500 and later, Philips iE33 Ultrasound System (Royal Philips, Amsterdam) with 8 and 12 mHz pediatric probes. From 2005 to 2010, a proprietary add-on system was used to capture digital images from the ultrasound machine. These files were sent to an mPACS server located at the tertiary care center. From 2010 to 2014, DICOM image acquisition was used to transfer files to a Vericis cardio PACS system (Merge Healthcare, Chicago, IL) at TAMC.

Tele-echocardiograms were completed by adult cardiac sonographers in Okinawa, Japan, and transmitted asynchronously for review by pediatric cardiologists in Hawaii. Cardiac sonographers received an initial 2 weeks of pediatric-specific echocardiography training followed by sustainment training every 6 months. Initial training at TAMC was conducted by two pediatric cardiologists and one registered pediatric cardiac sonographer. The curriculum included text and online self-study, classroom, and hands-on experience in the TAMC NICU and pediatric cardiology clinic. Sustainment training was performed every 6 months at USNHO during routine outreach pediatric cardiology visits and included approximately 50 pediatric cardiology clinic and neonatal intensive care echocardiograms with direct observation and training. After each tele-echocardiogram, the sonographers were provided online feedback from the pediatric cardiologist. This effort was challenged by the rotating nature of military assignments, where USNHO adult cardiac sonographers were often just out of training and transferred to another duty station within 2 years. The lack of continuity within this system required a robust training system supervised by the stakeholders.

Tele-consultations were initiated by the USNHO neonatologist via the Pacific Asynchronous TeleHealth (PATH) system, a web-based, store-and-forward, HIPAA-compliant platform for provider-to-provider telecommunication and aeromedical evacuation case management (TAMC, HI). After the consultation was placed, the sonographer completed the echocardiogram and transmitted the study data to TAMC. The pediatric cardiologist would access the study and place a written echocardiogram report in PATH. In emergent cases, the neonatologist and pediatric cardiologist would discuss the tele-echocardiogram via phone as soon as the study was uploaded. For non-urgent tele-echocardiograms that were completed after TAMC’s workday (there is a 5-hour time difference between Okinawa and Hawaii), echocardiograms could be read the following day.

All study data were obtained from the PATH system. Time of tele-echocardiogram request to charted echo report was calculated by using the time of the initial PATH echo consult to time of PATH report. Data regarding infant gestational age, reason for consult, diagnosis, and disposition was also collected. Studies were grouped into categories by study indication and gestational age.

This study was approved by TAMC’s Institutional Review Board.

Results

During the study period 100 infants received 192 tele-echocardiograms. The median time of tele-echocardiogram request to charted echo report was 18.6 h (range: 0.8 h to 109 h). Some 41% of infants were <30 weeks’ gestational age, 23% were 30 to <37 weeks’ gestational age, 36% were ≥37 weeks’ gestational age (Table 1). Of the infants, 46% had tele-echocardiograms completed for suspected patent ductus arteriosus, 28% for suspected congenital heart disease, 10% for possible congenital heart disease in the setting of other congenital anomalies, and 12% for possible congenital heart disease in the setting of likely pulmonary hypertension (Table 2). The most common anomaly on echocardiogram was patent ductus arteriosus (36%) followed by isolated ventricular septal defect (6%); 31 echocardiograms were normal (Table 3).

Table 1.

Gestational age of patient.

Gestational age	Percentage
Less than 30 weeks	41%
30 weeks to 36 6/7 weeks	23%
Greater than 37 weeks	36%

Table 2.

Reason for t-echo consult.

Indication	Percentage
Suspected patent ductus arteriosus	46%
Suspected congenital heart disease (CHD)	28%
Suspected CHD in setting of other congenital anomalies	10%
Possible CHD in the setting of likely pulmonary hypertension	12%
Possible CHD in setting of arrhythmia	3%
Suspected endocarditis	1%

Table 3.

Cardiac anomalies identified.

Diagnosis	Number
Patent ductus arteriosus	36
Normal	31
Ventricular septal defect (VSD)	6
Persistent pulmonary hypertension	5
Atrio-ventricular canal	5
Tetralogy of Fallot	2
Pulmonary hypertension with VSD	2
Hypertrophic cardiomyopathy with VSD	1
VSD with pulmonary stenosis	1
VSD with PDA	1
Hypertrophic cardiomyopathy	1
Mitral valve vegetation	1
Hypoplastic aortic arch with ventricular septal defect	1
Right aortic arch with aberrant left subclavian	1
Double outlet right ventricle	1
Severe cardiomyopathy	1
Cardiomegaly	1
Abnormal tricuspid valve and bicuspid aortic valve	1
Right ventricular hypertrophy and dilation	1
Left ventricular non-compaction	1

Some 59% of infants required >1 tele-echocardiogram. The most common reason for repeating a tele-echocardiogram was for patent ductus arteriosus follow-up (61%). The majority of premature infants diagnosed with patent ductus arteriosus were treated medically and then followed with repeat echocardiograms. The remainder of repeat tele-echocardiograms were obtained to follow a changing clinical course (for example tracking the severity of pulmonary hypertension) or monitor a previously diagnosed cardiac abnormality (for example isolated ventricular hypertrophy); 41% of transported infants required only one tele-echocardiogram.

Four tele-echocardiograms (2%) were inadequate to answer the clinical question. Two patients each required one additional tele-echocardiogram to re-evaluate suspected small ventricular septal defects (one apical and one mid-muscular). Another infant’s tele-echocardiogram was repeated one time to re-examine patent ductus arteriosus blood flow direction and intraventricular septal thickening (versus a prominent papillary muscle) in suspected pulmonary hypertension. Finally, in an infant with Trisomy 21, the initial tele-echocardiogram was unable to adequately assess aortic arch sidedness. This infant eventually received a CT angiogram to diagnose a right aortic arch and an aberrant left subclavian artery with slight mass effect on an adjacent artery. No care was delayed because of the need for additional imaging.

Because of the availability of tele-echocardiography, 17 infants were transported for cardiac reasons (Table 4). Of transport infants, 35% were <30 weeks’ gestational age, 18% were 30 to <37 weeks’ gestational age, and 47% were ≥37 weeks’ gestational age. Twelve (71%) patients were transported to Hawaii. Because Hawaii lacks interventional cardiac capabilities for complex heart disease, five (29%) infants were triaged for transport directly to the United States mainland for definitive treatment. Two of these infants were aeromedically evacuated on ECMO by the United States Air Force 59th Medical Wing, San Antonio, Texas. One infant was diagnosed with left ventricular non-compaction who did not tolerate an initial air transport attempt on mechanical ventilation. The second infant was a 9-month-old infant with a transitional AV septal defect and profound AV valve regurgitation in the setting of a pulmonary infection. Both infants were in medication-refractory heart failure. The remaining three CONUS-triaged infants were diagnosed with hypoplastic aortic arch, severe Tetralogy of Fallot, and AV canal in heart failure.

Table 4.

Outcome after t-echo.

Outcome	Percentage
No transport necessary	83%
Transport to Tripler Army Medical Center, Hawaii	12%
Transport to continental United States	5%

Discussion

Tele-echocardiography technology was introduced in the 1980s when fiber-optic broadband video circuits were used to transmit broadcast-quality video signals from regional hospitals to a tertiary medical center.⁶ As technology advanced, ISDN and T-1 telephone data lines were utilized to provide real-time and store-and-forward t-echo services.^5,7,11 Within the last 5 years, internet-based services have allowed the upload of echocardiogram data to secure servers. This data can then be accessed at any terminal with internet access.^4,9,10

Recent publications have demonstrated this shift in tele-echocardiography programs. For example, in 2014, Krishnan et al. evaluated 11,890 tele-echocardiograms at Children’s National Medical Center (Washington, DC) and documented their program’s transition from ISDN to internet protocol transmission for live studies by 2012. This program also offers tele-echocardiography access as far away as Guam, Morocco, and Uganda.⁴

While some internet-based services allow the pediatric cardiologist to view the study prior to completion, USNHO and TAMC uses a store-and forward system which cannot transmit the echocardiogram until the study is completed due to US Department of Defense security restrictions. An advantage to this system is that there is no restriction on file size, whereas real-time imaging fidelity depends on available bandwidth.

Our study used a store-and-forward system for several reasons. First, because of the 5-hour time difference between Okinawa, Japan and Honolulu, Hawaii, echocardiograms were sometimes not completed during each institution’s work day. In addition, it was technologically easier to upload echocardiogram files to a secure server versus managing a trans-Pacific videoconferencing system. Finally, there is no evidence in the literature of improved outcomes with real-time versus store-and-forward technology.^8,12,13

In contrast, advantages of real-time technology include allowing the pediatric cardiologist to provide instantaneous feedback to the technician and not requiring the sonographer to have additional pediatric training to complete an established protocol. In our study, the neonatologist could telephone the TAMC pediatric cardiologist for a read as soon as the echocardiogram was uploaded. This follow-up was often accomplished within an hour of ordering the study. In addition, in emergent studies, the TAMC pediatric cardiologist would often speak with the sonographer prior to the study to provide additional guidance for suspected diagnoses. If follow-up studies were needed, the TAMC pediatric cardiologist often directed the sonographer on what was required.

An obvious benefit of tele-echocardiography relates to cost saving and decreased patient risk through avoidance of unnecessary transports. In one study in Louisiana, the authors concluded that tele-echocardiography saved $7000 (1999 dollars) per avoided aeromedical evacuation. This study factored in the use of a helicopter, physician, and nurse to move an infant 200 miles to a tertiary care center.⁸ In our case, we were able to minimize the cost of transporting infants via fixed-wing aircraft over 4600 miles to Hawaii or over 6500 miles to mainland United States with aircrew, medical team, and ground ambulance transportation at the origin and destination. In addition, patients benefited from avoiding the risk of unnecessary transoceanic transports. Circumventing a 12-hour air-and-ground transport with limited personnel and resources conveys a significant benefit to the critically ill neonate. It is difficult to quantify to actual cost saving in our setting. Overseas US service members are not issued a bill for hospital or transport services so it is challenging to extrapolate monetary savings. In addition, multiple US Air Force airframes, each with different associated costs and primary missions, can be configured to transport neonatal critical care teams. The airframe and aircrew designated depended on the urgency of transport and availability of aircraft and aircrew. This can result in the infant being transported on a regularly scheduled mission, rerouted aircraft, or de novo flight. With each of these options, one can infer different degrees of cost and manpower.

In addition to an environment of variable aircraft and aircrew availability, caregivers at USNHO and TAMC contend with a certain amount of unavoidable time delay inherent to having a trans-Pacific transport approved, locating an available aircraft, and possibly waiting for the aircraft to arrive from another Pacific Air Base (if one is not readily available on Okinawa). In addition, what may seem at first to be a non-urgent transport can quickly morph into an emergent one because of an infant’s deteriorating clinical status. For example, what may begin as stable premature infant with a hemodynamically insignificant patent ductus arteriosus may quickly become an infant with a hemodynamically significant duct and associated hypotension and respiratory failure over the course of several days. Likewise, a benign-sounding murmur that can be followed clinically in a stateside NICU has greater implications if the infant is later diagnosed with Tetralogy of Fallot and requires an intubated trans-Pacific transport on prostaglandin. Because of these issues, the neonatologists at USNHO tend to request echocardiograms earlier and more frequently than providers might at a stateside NICU. Furthermore, because of the distances and logistics involved, an attempt was made to transport infants earlier in their disease course while the acuity level was lower.

One might argue that centers in South Korea or mainland Japan offer a more proximal location than Hawaii for tertiary care. However, this option presents language and logistic barriers issues for families of US Armed Forces personnel. Also, continuity-of-care and follow-up at these centers is more limited for infants of US military service members in contrast to continued care through the US Military Health System.

As well as preventing unnecessary transports, tele-echocardiography assists in triaging infants to appropriate tertiary care centers. For infants with diagnoses requiring interventional cardiac capabilities not available in Hawaii, transports could overfly Hawaii and transit directly to the United Stated mainland. This obviated a delaying stop at TAMC for pediatric cardiology consultation and reduced transit time, risk, and cost.

One important finding of this study was that there were no missed diagnoses of critical heart disease as evidenced post-discharge follow-up of non-transported infants in the Military Health System. Previous studies also support a very strong safety profile for tele-echocardiography.^6,7,12–14 On review of the literature, Casey et al. (1996) described two missed ventricular septal defects in a study of 10 patients.⁵ This study used two ISDN lines, which can be associated in decreased transmission quality (some centers used up to six lines to minimize fidelity loss).^15,16 In a more recent study of 665 t-echoes by Huang et al. (2008), one infant with critical coarctation of the aorta was missed. In this study, after a preliminary tele-echocardiography diagnosis of PDA, a coarctation was diagnosed 2 days later after hard-copy review of the mailed videotape. The neonate was immediately started on prostaglandin and transported for treatment.¹⁷

Our study also demonstrates the leveraging of adult sonographers for neonatal echocardiography. Adult cardiac sonographers at USNHO receive an initial 2 weeks of pediatric-specific training followed by sustainment training every 6 months during routine pediatric cardiology outreach visits. Other studies describe similar leveraging of adult sonographers with additional training in congenital heart disease, as most regional hospitals do not have pediatric/neonatal sonographers in the absence of a pediatric cardiology service.^8,14,17 Some studies, particularly in Europe, describe pediatricians, obstetricians, and geriatricians with additional training in echocardiography performing tele-echocardiograms for transmission to a cardiologist.^{5,12,15,16,18}

This study has several limitations. First, it is a retrospective evaluation of a single center’s experience with tele-echocardiography. While a randomized trial has previously been suggested to evaluate tele-echocardiography, this type of study is difficult because of the often emergent nature of congenital heart disease.^13,19 In addition, our study lacked a control group. One author addressed this challenge by comparing tele-echocardiography patients with patients prior to the introduction of tele-echocardiography.²⁰ Other authors compared tele-echocardiography patients with other patients without cardiac disease.^11,15,16 Finally, our study did not have a secondary method to verify tele-echocardiography diagnosis. Many real-time studies utilized a mailed hard-copy of the echocardiogram to verify the t-echo diagnosis.^7,12,13 In another study by Gomes et al. in 2010, a pediatric cardiologist traveled from a tertiary care center in Portugal to a regional hospital in the Azores to confirm the diagnoses of the transmitted studies.¹⁸ In our study, the echocardiogram file viewed by the TAMC pediatric cardiologist was the exact same file viewed by the USNHO sonographer and was not degraded by bandwidth limitations associated with ISDN and T-1 transmissions.

In conclusion, our study confirms that tele-echocardiography is an invaluable technology for remote NICUs in the triage of critically ill newborns that may have heart disease. This study is unique because of the long and potentially risky trans-Pacific transports involved, the use of tele-echocardiography to triage transports to destination centers with the most appropriate cardiac capabilities, and the leveraging of adult sonographers to complete neonatal echocardiograms in a remote location.

Footnotes

Acknowledgements

The authors would like to thank the men and women of the Neonatal Intensive Care Flight, 18th Medical Operations Squadron, Kadena Air Base, Okinawa, Japan, the United States Naval Hospital Okinawa, Japan, the Neonatal Intensive Care Unit, San Antonio Military Medical Center, San Antonio, TX, and Tripler Army Medical Center, HI for care provided to the infants in this study.

The views expressed in this article are those of the authors and do not reflect the official policy or position of the United States Air Force, United States Army, United States Navy, Department of Defense, or the US Government.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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