Use of Computerized Clinical Decision Support Systems to Prevent Venous Thromboembolism in Surgical Patients: A Systematic Review and Meta-analysis

Importance

Health care professionals do not adequately stratify risk or provide prophylaxis for venous thromboembolism (VTE) among surgical patients. Computerized clinical decision support systems (CCDSSs) have been implemented to assist clinicians and improve prophylaxis for VTE.

Objective

To evaluate the effect of implementing CCDSSs on the ordering of VTE prophylaxis and the rates of VTE.

Data Sources

PubMed, MEDLINE via OVID, EMBASE via OVID, Scopus, Cochrane CENTRAL Register of Controlled Trials, and clinicaltrials.gov were searched in June 2016 for articles published in English from October 15, 1991, to February 16, 2016. A manual search of references from relevant articles was also performed.

Study Selection

Clinical trials and observational studies among surgical patients comparing CCDSSs with VTE risk stratification and assistance in ordering prophylaxis vs routine care without decision support were included. Of the 188 articles screened, 11 (5.9%) were eligible for meta-analysis.

Data Extraction and Synthesis

Meta-analysis of Observational Studies in Epidemiology guidelines were followed. Two reviewers extracted data and assessed quality independently.

Main Outcomes and Measures

Rates of prophylaxis for VTE and VTE events. Random- and fixed-effects models were used to summarize odds ratios and risk ratios.

Results

Eleven articles (9 prospective cohort trials and 2 retrospective cohort trials) comprising 156 366 individuals (104 241 in the intervention group and 52 125 in the control group) were included. The use of CCDSSs was associated with a significant increase in the rate of appropriate ordering of prophylaxis for VTE (odds ratio, 2.35; 95% CI, 1.78-3.10; P < .001) and a significant decrease in the risk of VTE events (risk ratio, 0.78; 95% CI, 0.72-0.85; P < .001).

Conclusions and Relevance

Use of CCDSSs increases the proportion of surgical patients who were prescribed adequate prophylaxis for VTE and correlates with a reduction in VTE events.

Supratherapeutic anti-factor Xa levels in patients receiving prophylactic doses of enoxaparin: A case series

INTRODUCTION

Enoxaparin prophylaxis prevents venous thromboembolism in surgical patients. Real time anti-Factor Xa monitoring for surgical patients on enoxaparin prophylaxis is increasingly common.

PRESENTATION OF CASES

We report on three cancer patients with therapeutic or supratherapeutic anti-Factor Xa levels while on prophylactic doses of enoxaparin after surgical procedures. In all cases, elevated anti-Factor Xa levels were the result of blood specimens being removed from a heparinized chemoport.

DISCUSSION

This case series highlights the importance of peripheral venipuncture or appropriate blood wasting from central access sites for anti-Factor Xa levels.

CONCLUSION

Inappropriately drawn anti-Factor Xa levels may contribute to prophylaxis interruption or unnecessary workup for renal or liver failure.

Validation of the Caprini Venous Thromboembolism Risk Assessment Model in Critically Ill Surgical Patients

IMPORTANCE

Appropriate risk stratification for venous thromboembolism (VTE) is essential to providing appropriate thromboprophylaxis and avoiding morbidity and mortality.

OBJECTIVE

To validate the Caprini VTE risk assessment model in a previously unstudied high-risk cohort: critically ill surgical patients.

DESIGN, SETTING, AND PARTICIPANTS

We performed a retrospective cohort study of 4844 adults (≥18 years old) admitted to a 20-bed surgical intensive care unit in a large tertiary care academic hospital during a 5-year period (July 1, 2007, through June 30, 2012).

MAIN OUTCOMES AND MEASURES

The main study outcome was VTE (defined as patients with deep vein thrombosis or pulmonary embolism) that occurred during the patient's initial hospital admission.

RESULTS

The study population was distributed among risk levels as follows: low, 5.3%; moderate, 19.9%; high, 31.6%; highest, 25.4%; and superhigh, 14.9%. The overall incidence of inpatient VTE was 7.5% and increased with risk level: 3.5% in low-risk patients, 5.5% in moderate-risk patients, 6.6% in high-risk patients, 8.6% in highest-risk patients, and 11.5% in superhigh-risk patients. Patients with Caprini scores greater than 8 were significantly more likely to develop inpatient VTE events when compared with patients with Caprini scores of 7 to 8 (odds ratio [OR], 1.37; 95% CI, 1.02-1.85; P = .04), 5 to 6 (OR, 1.35; 95% CI, 1.16-1.57; P < .001), 3 to 4 (OR, 1.30; 95% CI, 1.16-1.47; P < .001), or 0 to 2 (OR, 1.37; 95% CI, 1.16-1.64; P < .001). Similarly, patients with Caprini scores of 7 to 8 were significantly more likely to develop inpatient VTE when compared with patients with Caprini scores of 5 to 6 (OR, 1.33; 95% CI, 1.01-1.75; P = .04), 3 to 4 (OR, 1.27; 95% CI, 1.08-1.51; P = .005), or 0 to 2 (OR, 1.38; 95% CI, 1.10-1.74; P = .006).

CONCLUSIONS AND RELEVANCE

The Caprini VTE risk assessment model is valid. This study supports the use of individual risk assessment in critically ill surgical patients.

Feasibility of the internal mammary lymph node flap as a vascularized lymph node transfer: A cadaveric dissection study

BACKGROUND

We performed cadaveric dissections to examine the feasibility of an internal mammary-based lymph node flap as a donor site for vascularized lymph node transfer.

METHODS

Internal mammary vessels and adjacent nodes were dissected in ten fresh cadaver specimens. Surgeon inspection and palpation identified the number of nodes in the specimen. Specimens were examined macro- and microscopically by a pathologist for correlation of lymph node counts. Kappa statistic correlated surgeon- and pathologist-reported node counts.

RESULTS

Surgeon- and pathologist-reported node counts were moderately correlated (kappa 0.57). Inspection and palpation correctly predicted node presence or absence in 80% of specimens. Sixty percent of flaps contained between 1 and 3 nodes, with a mean of 2.0 nodes when nodes were present.

CONCLUSIONS

Inspection and palpation predicts the presence or absence of nodes in 80% of flaps. Nodes were present in 60% of internal mammary-based flaps, and one to three nodes can be transferred. © 2015 Wiley Periodicals, Inc. Microsurgery 36:485-490, 2016.

A validated risk model to predict 90-day VTE events in postsurgical patients

BACKGROUND

VTE is the proximate cause of 100,000 deaths in the United States each year. Perioperative VTE risk among surgical patients varies by 20-fold, which highlights the importance of risk stratification to identify high-risk patients, in whom chemoprophylaxis can decrease VTE risk, and low-risk patients, for whom the risk-benefit relationship of prophylaxis may be unfavorable.

METHODS

We used data from a statewide surgical quality collaborative for surgical procedures performed between 2010 and 2012. Regression-based techniques identified predictors of 90-day VTE while adjusting for procedural complexity and comorbid conditions. A weighted risk index was created and was validated subsequently in a separate, independent dataset.

RESULTS

Data were available for 10,344 patients, who were allocated randomly to a derivation or validation cohort. The 90-day VTE rate was 1.4%; 66.2% of the derivation cohort and 65.5% of the validation cohort received chemoprophylaxis. Seven risk factors were incorporated into a weighted risk index: personal history of VTE, current cancer, sepsis/septic shock/systemic inflammatory response syndrome, age≥60 years, BMI≥40 kg/m2, male sex, and family history of VTE. Prediction for 90-day VTE was similar in the derivation and validation cohorts (areas under the receiver operator curve, 0.72 and 0.70, respectively). An 18-fold variation in 90-day VTE rate was identified.

CONCLUSIONS

A weighted risk index quantifies 90-day VTE risk among surgical patients and identifies an 18-fold variation in VTE risk among the overall surgical population.

Inadequate venous thromboembolism risk stratification predicts venous thromboembolic events in surgical intensive care unit patients

BACKGROUND

Surgical intensive care unit (SICU) patients are known to be at high risk for venous thromboembolism (VTE). The 2005 Caprini Risk Assessment Model (RAM) predicts VTE risk in surgical patients. However, a physician's ability to accurately complete this RAM and the effect that inaccurate RAM completion might have on VTE risk remain unknown.

STUDY DESIGN

Between 2009 and 2012, physicians completed a 2005 Caprini score for all SICU admissions at our institution. For comparison, we used a previously validated, computer-generated score. Regression-based techniques examined the effect of inadequate risk stratification on inpatient VTE risk, when controlling for other confounders.

RESULTS

Among 3,338 consecutive SICU admissions, 55.2% had computer-generated scores that were higher than the physician-reported score, and 20.6% of scores were equal. Computer-generated scores were higher than physician-reported scores for both median (6 vs 5) and interquartile range (5 to 8 vs 3 to 7). Inter-rater reliability between the 2 scores was poor (kappa = 0.238). Risk score underestimation by ≥2 points was significantly associated with inpatient VTE (7.67% vs 4.59%, p = 0.002). Regression analysis demonstrated that each additional day's delay in chemoprophylaxis (odds ratio [OR] 1.05, 95% CI 1.01 to 1.08, p = 0.011) and under-risk stratification by ≥2 points (OR 2.46, 95% CI 1.53 to 3.96, p < 0.001) were independent predictors of inpatient VTE, as were higher admission APACHE score, personal history of VTE, recent pneumonia, and younger age.

CONCLUSIONS

Physicians under-risk stratify SICU patients when using the 2005 Caprini RAM. As hospitals incorporate electronic medical records into daily practice, computer-calculated Caprini scores may result in more accurate VTE risk stratification. Inadequate VTE risk assessment and delay to chemoprophylaxis carry independent and significant increased risk for VTE.

The role of full-thickness scalp resection for management of primary scalp melanoma

BACKGROUND

Scalp melanoma is aggressive and has a proclivity for regional metastasis. We hypothesize that subperiosteal scalp melanoma resection reduces in-transit/satellite recurrence, when compared with subgaleal resection.

METHODS

We identified patients with intermediate to deep, primary scalp melanoma referred to head/neck surgery over an 8-year period. Patients were compared based on scalp resection depth, including subperiosteal (resection to the level of calvarium) and subgaleal (resection including skin, subcutaneous tissue, and galea). The dependent variables were in-transit/satellite recurrence and time to in-transit/satellite recurrence.

RESULTS

Among 48 identified patients, the in-transit/satellite recurrence rate was 16.7%. Subgaleal resection patients had higher in-transit/satellite recurrence rates than subperiosteal resection patients (24.0% vs. 8.7%, P=0.155). Among node-negative patients, subgaleal resection had significantly higher in-transit/satellite metastasis rates when compared with subperiosteal resection (26.3% vs. 0%, P=0.047).

CONCLUSION

For node-negative, primary scalp melanoma, subperiosteal resection significantly decreases in-transit/satellite recurrence when compared with subgaleal resection. Given our small sample size, further studies are necessary to confirm these results.

Assessment of postoperative venous thromboembolism risk in plastic surgery patients using the 2005 and 2010 Caprini Risk score

BACKGROUND

Venous thromboembolism is an important patient safety issue. The authors sought to compare the predictive capacity of the 2005 and 2010 Caprini Risk Assessment Models for perioperative venous thromboembolism risk.

METHODS

The authors performed a retrospective, observational, crossover study using an established surgical outcomes database. A total of 3334 adult plastic surgery patients were identified. Patients were risk-stratified using both the 2005 and 2010 Caprini Risk Assessment Models. Each patient served as his or her own control, resulting in precise matching for identified and unidentified confounders. The outcome of interest was 60-day, symptomatic venous thromboembolism. The predictive capacities of the 2005 and 2010 Caprini risk scores were compared.

RESULTS

Use of the 2010 Caprini Risk Assessment Model resulted in a systematic increase in the aggregate risk score. The median 2010 Caprini score was significantly higher than the median 2005 Caprini score (6 versus 5, p<0.001). When compared with the 2010 model, the 2005 Caprini Risk Assessment Model was able to better separate the lowest and highest risk patients from one another. Patients classified as "super-high" risk (Caprini score>8) using the 2005 Caprini Risk Assessment Model were significantly more likely to have a 60-day venous thromboembolism event when compared with patients classified as super-high risk using the 2010 guidelines (5.85 percent versus 2.52 percent, p=0.021).

CONCLUSIONS

When compared with the 2010 Caprini Risk Assessment Model, the 2005 Caprini Risk Assessment Model provides superior risk stratification. The 2005 Caprini Risk Assessment Model is the more appropriate method to risk-stratify plastic surgery patients for perioperative venous thromboembolism risk.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Stratifying the risk of venous thromboembolism in otolaryngology

OBJECTIVE

The consequences of perioperative venous thromboembolism (VTE) are devastating; identifying patients at risk is an essential step in reducing morbidity and mortality. The utility of perioperative VTE risk assessment in otolaryngology is unknown. This study was designed to risk-stratify a diverse population of otolaryngology patients for VTE events.

STUDY DESIGN

Retrospective cohort study.

SETTING

Single-institution academic tertiary care medical center.

SUBJECTS AND METHODS

Adult patients presenting for otolaryngologic surgery requiring hospital admission from 2003 to 2010 who did not receive VTE chemoprophylaxis were included. The Caprini risk assessment was retrospectively scored via a validated method of electronic chart abstraction. Primary study variables were Caprini risk scores and the incidence of perioperative venous thromboembolic outcomes.

RESULTS

A total of 2016 patients were identified. The overall 30-day rate of VTE was 1.3%. The incidence of VTE in patients with a Caprini risk score of 6 or less was 0.5%. For patients with scores of 7 or 8, the incidence was 2.4%. Patients with a Caprini risk score greater than 8 had an 18.3% incidence of VTE and were significantly more likely to develop a VTE when compared to patients with a Caprini risk score less than 8 (P < .001). The mean risk score for patients with VTE (7.4) was significantly higher than the risk score for patients without VTE (4.8) (P < .001).

CONCLUSION

The Caprini risk assessment model effectively risk-stratifies otolaryngology patients for 30-day VTE events and allows otolaryngologists to identify patient subgroups who have a higher risk of VTE in the absence of chemoprophylaxis.

The effect of increased hip flexion using stirrups on lower-extremity venous flow: a prospective observational study

BACKGROUND

Patient positioning during surgeries for colorectal cancer may represent an unrecognized risk factor for deep venous thrombosis.

METHODS

Twelve healthy control patients were positioned supine with knee flexion at 90°. Duplex ultrasound examined common femoral vein (CFV) and proximal femoral vein diameter, peak systolic velocity, and volume flow with hip flexion at 0°, 30°, 60°, and 90°. Data were analyzed using the paired t test.

RESULTS

In the CFV, hip flexion to 90° was associated with a significant increase in mean volume flow when compared with hip flexion at 0° (.59 vs .36 L/min; P = .05) and 30° (.59 vs .35 L/min; P = .038). In both the CFV and proximal femoral vein, increased hip flexion was associated with significantly reduced vessel diameter and increased peak systolic velocity.

CONCLUSIONS

Intraoperative positioning of the lower extremities represents a modifiable risk factor for deep venous thrombosis. When stirrups are used, hip flexion of 90° maximizes venous drainage from the legs.

The effect of abdominal wall plication on intra-abdominal pressure and lower extremity venous flow: a case report

Abdominal wall plication is known to cause increased intra-abdominal pressure (IAP). Whether plication-associated increased IAP causes lower extremity venous stasis, a recognized risk factor for DVT, remains unknown. A 55-year-old woman had a unilateral pedicled TRAM procedure for mastectomy reconstruction. Prior to plication, duplex ultrasound measured proximal femoral vein (PFV) cross-sectional diameter and volume-flow. PFV measurements were repeated immediately after plication and on post-operative days (POD) 1, 2, and 4. Bladder pressure was measured at similar timepoints. PFV volume-flow decreased from 0.22 L/min to 0.16 L/min (73% of baseline) immediately post-plication and reached a nadir of 0.08 L/min (36% of baseline) on POD 2. Bladder pressure increased from 13 mm Hg to 19 mm Hg after plication, and peaked at 31 mm Hg after intra-operative trunk flexion to 30°. Thus, abdominal wall plication was associated with increased intra-abdominal pressure and ultrasound-documented lower extremity venous stasis that persisted for 48 h after surgery.