Pulmonary embolism (PE), despite advances in medicine, remains a common and life-threatening event.1 According to the Centers for Disease Control and Prevention, 60 000 to 100 000 Americans die every year of complications from deep vein thrombosis/PE, with 10% to 30% of those deaths happening within 1 month of diagnosis.2
In the past decade, a number of advances in the treatment of PE have occurred. Most notable is the use of ultrasound-assisted thrombolysis (USAT).3 Ultrasound-assisted thrombolysis uses catheter-assisted thrombolysis to deliver a clot-dissolving medication directly to the clot while also delivering ultrasonic waves to further break down the clot. Alteplase, a thrombolytic drug, is the most commonly used medication to treat PE through USAT. In most cases, a heparin intravenous infusion is also used during therapy and post therapy. The most common insertion site for the USAT catheter is the femoral vein. The procedure for placement of the catheter is similar to that of a heart catheterization. A small catheter with holes at the end is placed via a femoral sheath and guided to the clot via radiology. Alteplase is delivered through the catheter directly to the clot via a continuous infusion until the recommended dose is delivered, usually 12 to 24 hours. During the infusion of the alteplase, the USAT machine delivers small ultrasound waves to further break down the clot. With the use of alteplase and the customary delivery location and method, there are significant risks to the patient, most particularly bleeding.4
The equipment most prominently used for USAT is the EkoSonic (EKOS Corporation, Bothell, Washington) machine (https://www.btg-im.com/en-US/EKOS/Home). At the time we began this search, the EKOS Corporation made no specific recommendations about nursing care during this procedure. At The Ohio State University Wexner Medical Center, our current nursing procedure uses the same practices that we use for EKOS when treating patients for deep vein thrombosis. Given the risks involved to the patient during and post treatment, our nursing team was curious whether there were any evidence-based practice guidelines specific to nursing care of the patient with PE during and post USAT treatment, especially when using the EKOS machine. A review of the EKOS website did not yield this specific information. Calls to 4 academic centers' nursing personnel yielded no nursing protocols or guidelines.
Thus, the objective of this integrative review was to explore the literature and web for any information on nursing practice with the use of USAT for adults with PE both during and post treatment. Our goal was to seek specific nursing assessments and practices to create a formal nursing policy and procedure specific for care of the adult patient with PE with EKOS/USAT treatment. We reviewed the evidence from observational and experimental studies as well as posted guidelines on the web.
We included observational studies as well as experimental studies that described or compared the use of USAT published after 2000 through June 2019. We excluded individual case reports, case series of less than 10 patients, and abstracts and conference proceedings. We also excluded technical reports. Study participants were adults and those with massive or submassive PE. Exclusion criteria included children and any articles for participants with conditions other than PE, such as deep vein thrombolysis. Last, only English-language articles and web postings were reviewed. We elected to not use quality of study design as an exclusion criterion because our aim was exploratory in nature. We were primarily interested in capturing any documented nursing procedures.
Electronic databases included PubMed, Web of Science, EBSCOhost, CINAHL, Google Scholar, and Google. Search terms in the title or abstract included “EKOS,” “ultrasound accelerated thrombolysis,” “ultrasound assisted thrombolysis,” “pulmonary embolism,” “nursing guidelines,” “evidence-based practice,” and “nursing practice.” We also searched reference lists of systematic reviews and relevant primary studies.
Quality of Research
We acknowledge the quality of research is an important factor when designing evidence-based guidelines. Our intent was to cast a wide net to capture any publication containing descriptions of practices within the scope of nursing practice. Our intent was not to evaluate the efficacy of EKOS/USAT intervention. Moreover, our searches yielded few articles to review. Hence, we elected to keep all publications meeting eligibility requirements without regard to the quality of the study.
Variables and Data Collection Procedures
Both authors independently assessed studies for eligibility using a standardized protocol that reviewed the title and abstract; if the 3 review authors agreed that the title and abstract contained sufficient information for exclusion (eg, pediatric sample), then the article was rejected. Two authors independently reviewed all studies using a standardized data collection form and procedure. A third nurse randomly selected one-third of the studies for independent review. Any disagreements were resolved by discussion among the 3 reviewers. We extracted information about the study design, setting, participants (demographics, type of PE, inclusion and exclusion criteria), medications and doses (thrombolytic agents and heparin), access characteristics, and bleeding events. Nursing practice information included monitoring and surveillance before, during, and post procedure, sheath removal, and compression practices.
Of the 249 references retrieved, 89 were duplicates and 138 did not meet the eligibility criteria (Figure). Thus, 22 articles met the inclusion criteria (Table 1), published between 2008 and 2019.5–26 Most (86%) were single-site studies,5,7–11,13–17,19–26 retrospective in design (77%),5–11,13–15,17–19,22,23,25,26 and with sample sizes of less than 50 participants (55%)5–7,9,10,14,17,19,20,22,24,26 (sample size range, 10–150; total number of subjects receiving USAT, 938). Sample characteristics consisted of both genders (proportion of men ranged from 28% to 64%), and average ages ranged from 52 to 74 years. Levels of PE treated were submassive PE only,5,7,10,12,15,17,22 massive PE only,6,14,20 or both submassive and massive PE.8,9,11,13,16,18,19,21,23–26 Whether patients experienced multiple PEs was not always noted.
Characteristics of Access, Tissue Plasminogen Activator Dose Range, and Heparin Infusion
Access Characteristics. All but 1 study20 described access. Access was most frequently single femoral.5–9,11–14,16–19,21–24,26 Other access sites included bilateral femoral7,9–12,14,16,17 and jugular.6,13,15,18,24,26,27 For single-lumen insertions, infusion catheters ranged from 5.2F to 5.4F, and vascular sheaths ranged from 6F to 8F (see Table 2). Of the studies that documented placement of the catheter, most insertions took place in the cardiac catheterization laboratory7–9,12,20,25,26; other settings included the angiographic suite,13,19 vascular catheterization laboratory,16 interventional radiology laboratory,11 or operating room.13 Clinician operants were usually not noted but included vascular surgeons,10,18 interventional radiologists,11,18,19,25 interventional cardiologists,15,18 or cardiovascular surgeons.18,24
Medications and Administration. After initial catheter insertion, ongoing infusion of the thrombolytic agents took place in the intensive care unit,8,9,11,13,16,19,20 intermediate unit,8 coronary care unit,17,25,26 or angiographic suite.7 Of the studies that designated the specific drug, the most commonly used tissue plasminogen activator was alteplase5–16,18–26; other drugs included reteplase6,17 and urokinase.6,14,21 Thrombolytic infusion times ranged from 10 to 49 hours. Bolus or loading doses were reported in 7 studies.8,9,13,15,16,20,25 Total dosages varied based on use of a bolus or loading dose, single versus bilateral lumen, and time allotted for infusion. Mean total doses of tissue plasminogen activator were less than 20 mg,14 between 18 and 28 mg,13,18,21,22,24,26 or between 31 and 36 mg.8,11,16,17,20,23,25 Maximum dosages of 20 mg,12,15 24 mg,10 and 30 mg8 were indicated in several studies. Heparin was not delivered simultaneously with thrombolytic therapy in several studies.6,7,13,23 Descriptions of heparin therapy included targeted infusions based on partial thromboplastin time thresholds,5,10,11,15,17,18,20,24 bolus dosage,8,12 subcutaneous dosages,9 and/or infusion rates.12,14,16,19,21,22,25,26
Sheath Removal Procedures and Nursing Practices. A number of studies made no mention of sheath removal procedures.5–7,11,14–17,19,20,22–25 Several specified removal of the sheath at the bedside, but no indication of the professional (eg, nurse, physician) who removed the sheath.8,9,12,13 Manual compression at the insertion site was noted in 4 studies, with times described until local hemostasis was achieved,8,12 for a minimum of 5 minutes10,18 or 15 minutes.24 None of the articles mentioned who applied the manual compression. Finally, none of the articles documented nursing assessments, care, or procedures before, during, or post USAT.
Access Site Bleeding Events. Four studies provided no details regarding minor or both minor and major bleeding events.8,16,17,20 Fifteen studies reported 1 fatal, 12 major, 4 moderate, and 36 minor bleeding events at the catheter insertion sites.5–7,9–12,14,15,18,19,21–24,26
Evidence-based practices are essential to providing safe quality care. We found insufficient information in our integrative review to guide the development of an evidence-based guideline in caring for the patient population with PE undergoing treatment using USAT. We used various databases to gather this information, from CINAHL to a simple, broad Google search. We also contacted colleagues at other major tertiary care centers to query whether they had specific guidelines, policy, or procedures for care of the patient with PE or who underwent USAT. Given that the USAT treatment for PE is a more recent development, it is not surprising that there are no current nursing evidence-based practices for the care of the patient with PE receiving USAT.
Nevertheless, our findings do have implications for nursing practice. First, despite USAT requiring lower dosages of thrombolytic agents compared with traditional catheter infusion, there remained a 5% bleeding event at the insertion site. Second, the clinical setting for the insertion and subsequent continuous infusion varied. The setting affects the numbers of available nurses as well as the training and expertise of nurses. For example, some studies reported that, after initial catheter placement, patients were transferred to either an intermediate or intensive care unit, which has significant impact on the patient numbers assigned to nurses.8,12 Worldwide, intermediate care units can vary in size and specialties. Intermediate care patients per nurse can range from 1 to 11; in the United States, the number of patients to nurse is approximately 4.28 Intensive care units have less variation in the nurse-patient ratio, with most units having 1 to 2 patients in the ICU assigned to a nurse, as found in a recent study examining 1265 ICUs in 75 countries.29 Staffing and workforce issues impact patient outcomes29,30; moreover, time constraints related to higher patient loads can lead to missed nursing care, distractions, and interruptions.31,32
There are several limitations of the study. First, we elected to use any study that reported on 10 or more patients who underwent USAT. This likely resulted in reporting bias. For example, elements of information were lacking ranging from medications, bleeding events, clinical setting, and sheath removal and compression practices, all of which impact the delivery of nursing care. Second, we did not retrieve or use non-English articles, abstracts, or proceedings from conferences. These sources may have provided additional information.
Because we were unable to find any evidence to guide nursing practice, we will continue to use our current procedures and protocols. Future changes will be based on ongoing review and evaluation of patient outcomes. We recommend nurses initiate greater involvement in the implementation and evaluation of new technologies and procedures, as with the case of USAT in those with PE. Creation of a standardized guideline for care of patients with PE who undergo USAT treatment is needed.
What’s New and Important
- Use of USAT for the delivery of thrombolytic agents to PE has been developed recently.
- A review of the literature showed that variation exists on the clinician specialist, clinical area for catheter placement, clinical area for infusion therapy, amount and duration of delivery of medication, and lack of information on sheath removal or compression procedures.
- Nurses must initiate greater involvement in the implementation and evaluation of new technologies and procedures to standardize and evaluate care.
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