Critical Appraisal



Critical AppraisalGeraldine SanfillippoThomas Edison State CollegeEvidence Based Nursing PracticeNUR- 530April 30, 2011AbstractIt is anticipated that there will be an increase in the number of patients diagnosed with Acute Ischemic Stroke (AIS). In addition to neurological deficits these patients are faced with a host of medical complications including venous thromboembolic disease (VTE). This condition has received a great deal of interest in terms of appropriate methods of assessment, treatment and intervention. According to the American College of Chest Physicians, all patients with neurological conditions should receive prophylaxis for (VTE). Is the proper therapy for prevention the use of graduated compression stockings (GCS) or pharmacological management the best prophylaxis? There is a wide variety of treatments used in clinical practice for thromboprophylaxis based on information obtained from several randomized clinical trials. A review of the literature will look at the evidence for GCS and the use of heparin and low molecular weight heparin as well as the combined use of both methods.Clinical QuestionPatient Population of Interest: All adult hospitalized patient with a diagnosis of acute ischemic stroke or presenting with signs or symptoms of stroke.Intervention of interest: Is the prophylaxis’s use of Sequential Compression Device (SCD) Stockings, in the acute stroke patient confined to the hospital adequate enough to prevent the development of venous thromboembolism?Comparison of Interest: The combination use of both mechanical and pharmacological intervention to prevent the development of venous thromboembolism?Outcome of Interest: To improve the patient’s outcome through the prevention of venous thromboembolism is the hospitalized patient with acute ischemic stroke supporting the use of both mechanical and pharmacological measures.Clinical Question: In the acute ischemic stroke patient (P), is the use of mechanical sequential compression devices alone (I) or the combination use of both mechanical and pharmacological measures (C) provide better prophylaxis to improve patient outcome in the prevention of venous thromboembolism?Background: Approximately half of the deaths in the period immediately following an ischemic stroke are the result of secondary complications rather than the brain insult itself. Venous thromboemolic disease is considered a secondary complication and preventable in a majority of patients with proper prophylaxis. Is the stocking method currently used in the surgical population adequate for the stroke population? Annotated BibliographyMuir, K.W., Watt, A., Baxter, G., Lees, K.R. (2000). Randomized trial of graded compression stockings for prevention of deep vein thrombosis after acute stroke. QJM: An International Journal of Medicine 93(6) 359-364 This article portrays information obtained through a study conducted to determine the efficacy of current treatment modalities for the prevention of deep vein thrombosis (DVT). The target audience for this study would be Physicians, Nurses Executives, Medical Executives and Registered Nurses and Advanced Practice Nurses. The study was conducted on patients admitted to an acute stroke unit with a clinical diagnosis of acute stroke. Patients were randomized through a computer generated number, placed in a sealed envelope, to standard care of DVT or standard care with the use of full length stockings. This article was chosen to be included in the annotated bibliography because of its significance in the potential prevention in DVT incidence in the acute phase of stroke. The study takes into consideration advances in care delivery of the acute stroke patient such as the use of aspirin, early ambulation and hydration to have an effect on the reduction of DVT incidences in addition to early heparin treatment and the effectiveness of graded compression stockings. The study spanned a period from April 1995 to December 1997 with 1070 patients screened. Of those screened 98 were actually recruited into the study. This article would rate a level 11 for the hierarchy of evidence as a randomized controlled trial with a blinded data review. There was an assumption in the study for results of 50% DVT incident and a 50 % relative risk reduction with the use of stockings. These assumptions were based on systematic review of patient with other conditions other than stroke. The study had an 80 % power to detect this difference with 100 randomized patients in a 2:1 ratio of standard treatment to stockings. Results of the study confirm DVT continues to be a significant problem in the immobile acute ischemic stroke patient with 22 % of the control group in the first nine days. Clinical manifestation of DVT being rare with 1 out of 14 or 7 %, however 9 out of 14 or 64 % were present on initial assessment within the first 24 hours of admission. The study demonstrated results indicating a reduction in the development of early DVT with the use of compression stocking. Comparison of proximal to distal DVT prevention, the study shows less certainty regarding the efficacy of this intervention for the prevention of proximal DVT’s. The article refers to numbers needed to treat (NNT) of 61 percent a proximal DVT versus NNT of 9 for any other DVT. One area to consider is the number of ischemic stroke patient with the ability for early immobilization or early discharge who would likely dilute the benefits of GCS. In order to determine the efficacy of stockings as it related to a reduction in DVT would require a significant number of approximately 750 participants per group. Additional studies need to be designed that take into consideration the demands on nursing time and the relevance of stocking design.Validity: This study was a randomized controlled study with blinded data review. Patients were randomized through a computer generated number, placed in a sealed envelope, to standard care of DVT or standard care with the use of full length stockings. Standard care for the Ischemic Stroke patient includes brain imaging, aspirin therapy, early immobilization and intravenous fluid therapy. : The study spanned a period from April 1995 to December 1997 with 1070 patients screened. Of those screened 98 were actually recruited into the study. Patients included in the study were clinically diagnosed with ischemic stroke and were not able to ambulate independently with in the first 24 hours of admission to the hospital. An additional consideration was the ability to maintain leg raising against gravity for a five second period. Reliability Factors that could affect reliability are the small number of study participants and a significant number of drop outs before additional assessment could be provided. In order to determine the efficacy of stockings as it related to a reduction in DVT would require a significant number of approximately 750 participants per group. Results of the study confirm DVT continues to be a significant problem in the immobile acute ischemic stroke patient with 22 % of the control group in the first nine days. Clinical manifestation of DVT being rare with 1 out of 14 or 7 %, however 9 out of 14 or 64 % were present on initial assessment within the first 24 hours of admission. The study demonstrated results indicating a reduction in the development of early DVT with the use of compression stocking. Comparison of proximal to distal DVT prevention, the study shows less certainty regarding the efficacy of this intervention for the prevention of proximal DVT’s. The article refers to numbers needed to treat (NNT) of 61 percent a proximal DVT versus NNT of 9 for any other DVT.Applicability: The result of this study does show some support in favor of the use of graded compression stockings (GCS) for the prevention of DVT in the acute stroke patient. The data is largely in line with evidence from additional studies done for other clinical conditions. The study shows reduced risk of early DVT with GCS above standard management but addressed the need for further clarification in a larger population. Dennis, Martin S., (2004). Effective prophylaxis for deep vein thrombosis after stroke: Low dose anticoagulation rather than stockings alone. Stroke. 2004; 35: 2912-2913 The review of this article reveals an audience of physicians and nurses in a systematic review of randomized control studies addressing the use of heparin in the acute stroke population in addition to the standard care of graded compression stockings. Management of the patient was similar to other studies with the use of aspirin within 48 hours in addition to early mobilization and hydration. Consideration was given to those patients who presented with a greater risk for the development of venous thrombosis and a low risk for hemorrhage. This article seemed appropriate to include in the bibliography since it addresses the comparison of interest in my clinical question; the combined use of both mechanical and pharmacological intervention to prevent the development of venous thrombosis. The evidence provided by this study itself is non-conclusive for combined therapy. The study further questions the use of the application of graded compression stockings as the standard approach to prevention of venous thrombosis. Evidence supports that the use of GCS prevents the development of DVT from an analysis of approximately 19 small randomized studies by two-thirds. The concern identified in this article is that most studies are performed on the surgical patient. This facility looked at the amount of time spent in the application and monitoring of the proper use of GCS as it related to nursing time. If compression stockings were not an effective means for prevention of DVT than nursing time could be utilized in other ways. This article would rate a level 1 for the hierarchy of evidence with the use of a Meta analysis of 19 small randomized control trials. The author tends to demonstrate a bias toward the use of compression stockings on stroke patients since most studies done have addressed the surgical patient and there is a lack of hard evidence. The study addresses one additional randomized control trial used to determine the efficacy of stockings in stroke patients but the numbers were far too small to determine effectiveness. Additionally, the only type of stocking used was thigh high with no consideration given to below the knee stockings. Participants from this study were enrolled in a much larger Clot in Legs Or TEDS after Stroke Trial (CLOTS). Validity: This study is clearly focused on the clinical question, the combined use of both mechanical and pharmacological intervention to prevent the development of venous thrombosis. The study identifies the meta analysis of approximately 19 small randomized controlled trials of heparin in acute ischemic stroke but without mentioning the actual study or results. Reliability: Heparin was used for DVT prevention is a selected group of patient who demonstrated a higher risk for DVT and less likely at risk for hemorrhagic complications. There was no mention of the number of participants in the study. The author tends to demonstrate a bias toward the use of compression stockings on stroke patients since most studies done have addressed the surgical patient and there is a lack of hard evidence.Applicability: Consideration was given to this study because it addresses the combination therapy of compression stockings with the use of low dose anticoagulation in addition to the standard measure of early mobilization and adequate hydration. The CLOTS Trial Collaboration (2010). Thigh-length versus below –knee stockings for deep venous thrombosis prophylaxis after stroke. (2010, November). Annals of Internal Medicine, 153(9), 553-562. Retrieved from This article portrays information obtained through a study conducted to review all the current treatment modalities used in the prevention of deep venous thrombosis (DVT).The treatments considered are the use of graduated compression stockings either alone or in combination with intermittent pneumatic devices or anticoagulation. The design of the study was a group trial with centralized randomization that included 112 hospitals in 9 countries. The target audience for this study would be Physicians, Nurses Executives, Medical Executives and Registered Nurses and Advanced Practice Nurses. Consideration of this article was given because it looked at all modalities of treatment and had a patient group of 2518 hospitalized acute stroke patient who were not initially mobile. Most comparative studies have been conducted in surgical patients. This study identifies that the use of graduated stockings are widely used in the prevention of DVT in stroke patients with no reliable evidence to support the use of thigh high or below the knee stockings. The study depended on the ability of the nursing staff to properly identify the appropriate size, fitting and monitoring of the use through documentation. This study is important to determine the efficacy of compression stockings in the care of the acute stroke patient. This article would rate a level 11 for the hierarchy of evidence with the use of parallel group trial with centralized randomization. Identification of DVT was determined though compression duplex ultrasonography in 1406 patients in each category between day 7 and 10 of admission. A second scan was performed on 643 patients in the thigh high stocking group and 639 in the below the knee group at 25 to 30 days beyond initial stroke. The primary outcome results were symptomatic or asymptomatic DVT detected on either scan performed. Primary outcome occurred in 98 patients (6.3%) with thigh high stockings and 133 (8.8%) with below the knee stockings. Seventy five percent of the participants involved in the study wore their stockings for a period of up to 30 days or until complete mobilization occurred. There were limitations of the study because blinding was incomplete; the ultrasonographers were the only group blinded and scans were not completed on all enrolled participants. The study concluded that proximal DVT‘s occurred more frequently in the group of patient who wore below the knee stockings in the study. The result obtained from CLOTS has important implications when practice is considered. It suggests that thigh high stockings have better clinical outcomes for the ischemic stroke patient.Validity: The CLOTS trial is a collection of three multicentre randomized studies that use the same randomization, data collection and follow – up systems to access the risks and benefits of external compression devices in the ischemic stroke patient. Each of the three trials tests the effectiveness of the addition of GCS to routine stroke care. This trial is an outcome- blinded randomized controlled trial consisting of 2518 immobilized patients admitted to a hospital within one week of onset of an acute ischemic stroke. Patients were placed into groups via a central randomization system either standard stroke care plus thigh high stockings graded compression stockings (GCS) (n=1256) or routine care plus knee high stockings GCS (n= 1262)Reliability: With 2518 participants in the trial, the study had a 90 % ability to detect a 4% risk reduction in the development of DVT. Based on the primary outcomes of each group and there was a calculated 95 % CI. Results of the primary outcomes were adjusted for four variables, predicted stroke outcome, the time of onset of stroke symptoms to participation in trial and the ability to raise both legs of the bed for a prescribed 5 seconds in addition to the use of anticoagulants. All were based on the intent to treat ("The CLOTS (Clots in Legs or stockings after Stroke) Trial Collaboration," 2010, p. 4). Consideration to the reliability of the trial needs to be given to the incorrect use of GCS and the compliance of use since both may affect the effectiveness of the intervention. Applicability: The results of this study make the assumption that the use of thigh high stockings should be the preferred intervention until additional studies are conducted to encourage the use of below the knee stocking or no intervention. These results are consistent with other studies conducted on the use of graded compression stockings for the ischemic stroke patient. These results may have important significance on future practice and research in the care of the patient with and ischemic stroke. Albers, G. W., Amarenco, P., Easton, J. D., Sacco, R. L., & Teal, P. (Eds.). (2004). Antithrombotic and thrombolytic therapy for ischemic stroke: The seventh ACCP conference on Antithrombotic and thrombolytic therapy. Chest: The cardiopulmonary and critical care journal, 126(3), 497. This journal chapter provides evidence based guidelines for the prevention of deep vein thrombosis in the acute ischemic stroke patient. These guidelines target clinicians who routinely care for the stroke population or those who will identify treatment protocols. The audience includes Physicians, Nurses Executives, Medical Executives and Registered Nurses and Advanced Practice Nurses. This article is presented with content consistent with that of a scholarly medical source, The American College of Chest Physicians (ACCP). Discussed in this chapter are the grade 1 recommendations for the immobilized patient diagnosed with an acute ischemic stroke. Grade 1 recommendations are strong and indicate the benefits do or do not outweigh the risks, burden or cost of the intervention (Albers, Amarenco, Easton, Sacco, & Teal, 2004). The recommendation by the ACCP is the prophylactic use of low dose subcutaneous heparin or low molecular weight heparin. For those patients with a contraindication to this therapy the recommendation is the use of pneumatic compression device. This article would rate a level 1 for the hierarchy of evidence based on the use of results obtained from clinical trials. The overall validity of these recommendations is based on the results of 10 trails in 1993 that evaluated the use of Heparin in 1047 patient with a diagnosis of Acute Ischemic Stroke. The study reveals an outcome of 80 % reduction in the incidence of DVT. The recommendation of the American College of Chest Physicians for patients with restricted mobility is to consider the use of low dose subcutaneous heparin or low molecular weight heparin. The number needed to treat (NNT) was used to approximate the number of participant need to receive an intervention to prevent a DVT. This recommendation is consistent with the finding of other studies for the use of heparin in the prevention of DVT in the immobilized stroke patient.Validity: The American College of Chest Surgeons base their recommendations on a review done in 1993 of 10 trials evaluating the use of heparin in 1047 patient with an acute ischemic stroke diagnosis. These trials were randomized controlled trials as well as cohort studies. Each individual study was not identified for this particular measure. The following two studies were identified in the analyses; International Stroke Trial (IST) and Trial of Acute Stroke treatment (TOAST) The interventions reviewed were the use of prophylactic low dose subcutaneous heparin or low molecular weight heparin and the use of pneumatic compression stockings. The interventions were studied on the population of acute ischemic stroke patients with restricted mobility or with contraindications to pharmacological intervention.Reliability: Data collected from the meta analysis and placebo controlled blinded randomized studies have resulted in little to no increased risk for bleeding with the use of heparin or low molecular weight heparin. These results were compared against the three different methods of mechanical prophylaxis and have shown that while mechanical is effective it is less intense than the use of heparinoids for the prevention of DVT. The IST reported an 80% reduction in the formation of DVT with pharmacologic intervention. In the TOAST study, DVT again were significantly reduced with the use of heparinoids. Consistent with other trials, it was identified for the acute stroke patient few randomized trials have been done to recognize any significant decrease in the risk of DVT complications. This is a grade 1 A recommendation based on strong evidence that the benefit of the intervention outweighs the associated risks. Applicability: The American College of Chest Surgeons recommendation for the acute ischemic patient with decreased or restricted mobility is the use of prophylactic subcutaneous heparin or low molecular weight heparin. For those with contraindications to the use of heparin it is recommended the use of intermittent pneumatic compression devices or stockings. This recommendation has significant impact on the population served in our institution. It has become part of the standard of care for all patients admitted with ischemic stroke in combination with the use of pneumatic stockings. Naccarato, M., Chiodo, G. F., Dennis, M., & Sandercock, P. (2010). Physical methods for preventing deep vein thrombosis in stroke [Review of the book The Cochrane Collaboration]. The Cochrane Collaboration, 1-26. Retrieved from The Cochrane Review exhibits information and data related to the effectiveness and safety of physical methods used in the prevention of deep vein thrombosis in the acute stroke patient. The method of study was a randomized controlled trial comparing various physical methods used to reduce the risk of DVT. The target audience included Registered Nurses, Physicians, and Advanced Practice Nurses and Nurse Executives. This article has been chosen because it looked at the results obtained from previous studies as they related to the surgical patient and sought to access their effects in the acute stroke patient (Naccarato, Chiodo Dennis, & Sandercock, 2010, p. 1). The review looks at the effect of the various physical methods used in the prevention of clot formation in the stroke patient. Evaluation is given to two randomized trials of graduated compression stockings and two trials of intermittent pneumatic compression devices. Overall, the data provided does not support the routine use of graduated compression stockings or intermittent pneumatic compression stockings in the acute stroke patient. There was no clinically or statistically significant outcomes identified. This article would rate a level 1 for the hierarchy of evidence based on the use of randomized controlled studies of graduated compression stockings with 2615 patients and two smaller studies with 177 patients for the use of intermittent pneumatic compression. Data was studies where prophylaxis was started within seven days of the onset of symptoms of stroke. A Cochrane review of acute stroke patients with anticoagulation discovered treatment with heparin or low molecular weight heparin as associated with a significant reduction (64%) in therisk of developing a DVT a confidence interval of 95%. The review identifies the risk of bias in included studies. In one study, the method of randomization was unclear as to whether or not the scans were assessed blind to the treatment location. Another study shows patient were randomized using computer generated random numbers in sealed envelopes (Muir 200). The majority of the data for this review comes from the graduated compression stockings GCS trials and CLOTS 2009. Validity: This review looked at randomized controlled groups of patients comparing the Various physical methods of DVT prevention with a control group when the intervention was started within seven days of onset of symptoms. Included in the study were two randomized trials with 2615 participants using GCS and two smaller studies with 177 participants involving the use of intermittent pneumatic compression stockings. This review looked at physical interventions as they compare to anticoagulant drugs to reduce the risk of DVT. The participants used were considered for the study based on the ability to raise their legs for an prescribed period of five seconds, decreased mobility and seven days of onset of stroke symptoms.Reliability: The systematic review of various studies of anticoagulants in patient with heparin or low molecular weight heparin has significantly reduced the development of DVT by 64%. This carries a 95% CI or confidence interval for a relative risk reduction of 54 to 71%. Data for this review was primarily obtained from the CLOTS 2009 and the GCS trials . Applicability: The trials reviewed do not support the routine use of graduated compression stockings or the use of intermittent pneumatic compression stockings as prophylaxis in the prevention of DVT in the acute ischemic stroke patient. The findings were consistent with other trials and identified a need for additional trials with larger numbers to be conducted. Summary In the acute ischemic stroke patient (P), is the use of mechanical sequential compression devices alone (I) or the combination use of both mechanical and pharmacological measures (C) provide better prophylaxis to improve patient outcome in the prevention of venous thromboembolism? Overall the literature suggests the use of chemical prophylaxis for DVT in the treatment of acute ischemic stroke patients. The American College of Chest Physicians recommends this therapy as a Grade 1 recommendation in their evidence based practice guideline. The use of GCS is not routinely recommended as prevention for DVT in the acute stroke patient unless there is a contraindication to the use of anticoagulation therapy. The CLOTS trial provides strong evidence suggesting the routine use of GCS in acute ischemic stroke patients does not decrease the risk of DVT significantly. Based on the findings , this would not influence a change in practice from the anticoagulation therapy. Additional trials need be conducted on the benefits and harm of the use of mechanical prophylaxis alone and with the combined therapy of mechanical and chemical prevention of DVT.ReferencesAlbers, G. W., Amarenco, P., Easton, J. D., Sacco, R. L., & Teal, P. (Eds.). (2004). Antithrombotic and thrombolytic therapy for ischemic stroke: The seventh ACCP conference on Antithrombotic and thrombolytic therapy. Chest: The cardiopulmonary and critical care journal, 126(3), 497.Dennis, M. S. (2004). Effective prophylaxis for deep vein thrombosis after stroke: Low dose anticoagulation rather than stockings alone . Stroke, 35, 2912-2913. doi: 10.1161/.01STR.0000147720.27350.09Muir, K. W., Watt, A., Baxter, G., Grosset, D. G., & Lees, K. R. (2000). Randomized trial of graded compression stockings for prevention of deep-vein thrombosis after acute stroke. QJM: An International Journal of Medicine, 93(6), 359-364. Retrieved from , M., Chiodo, G. F., Dennis, M., & Sandercock, P. (2010). Physical methods for preventing deep vein thrombosis in stroke [Review of the book The Cochrane Collaboration]. The Cochrane Collaboration, 1-26. Retrieved from CLOTS Trial Collaboration (2010). Thigh-length versus below –knee stockings for deep venous thrombosis prophylaxis after stroke. (2010, November). Annals of Internal Medicine, 153(9), 553-562. Retrieved from ................
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