Personalisation and embodiment in e-Learning for health professionals: A randomised controlled trial

PURPOSE

Mayer's theory of multimedia learning proposes that personalisation and embodiment (P/E) can improve outcomes in e-Learning. The authors hypothesised that an e-Learning module enhanced by P/E principles would lead to higher knowledge, perceived P/E and motivation among health care professionals, compared with an unenhanced module.

METHODS

The authors conducted a randomised trial comparing two versions of a 30-minute multimedia e-Learning module addressing the antibiotic management of pneumonia. The unenhanced format used slides with voiceover (human voice but no visible speaker), formal language and no specific P/E strategies. The enhanced format additionally implemented P/E strategies including conversational style, polite language, visible author, social congruence, human-like presence and professional presence by subtly changing the script and substituting several short videos of subject matter experts. Participants included pharmacists, physicians and advanced practice providers from three academic and several community hospitals. Outcomes included knowledge, perceived P/E (assessed by the Congruence Personalisation Questionnaire, CPQ), motivation (assessed via the Instructional Materials Motivation Survey [IMMS] and Motivated Strategies for Learning Questionnaire [MSLQ]) and course satisfaction.

RESULTS

There were 406 participants including 225 pharmacists, 109 physicians and 72 advanced practice providers. Post-module knowledge was slightly higher for the enhanced versus the unenhanced format, but the difference did not reach statistical significance (adjusted mean difference, 0.04 of 10 possible, [95% CI -0.26, 0.34], p = 0.78; Cohen d 0.02). Participant perceptions of P/E (measured via CPQ) were significantly greater for the enhanced format (difference 0.46 of 5 possible [0.35, 0.56], p < 0.001; Cohen d 0.85), as were motivational features of the e-Learning course (measured via IMMS) (difference 0.14 of 5 possible [0.02, 0.26], p = 0.02; Cohen d 0.24). Participants' overall motivational orientation (measured via MSLQ) and course satisfaction were not significantly different between the two formats (p > 0.05).

CONCLUSION

Application of P/E principles to an e-Learning module led to greater perceived P/E and motivational features but did not influence knowledge.

The Incidence of Torsades de Pointes With Perioperative Triple Antiemetic Administration

BACKGROUND

The safety of triple antiemetic therapy consisting of ondansetron, haloperidol, and a steroid, to surgical patients is unknown.

OBJECTIVE

To determine the incidence of torsade de pointes (TdP) or death following perioperative administration of triple antiemetic therapy.

METHODS

A retrospective cohort study identified 19,874 patients who received 22,202 doses of triple antiemetics during the 2.5-year time frame from March 4, 2020 to September 7, 2022 for surgical nausea prophylaxis or treatment of nausea. These patients above were cross-matched with an electrocardiogram and adverse outcome database; this identified 226 patients with documentation of a QTc > 450 ms, all ventricular tachycardias including TdP within 48 hours of receiving triple antiemetic therapy, or death within 7 days of receiving ondansetron.

RESULTS

There were 3 patients who had documented VT (n = 3), but there were no documented incidents of TdP (n = 0). There were 9 codes called on patients within 48 hours of medication administration, and none of them were due to ventricular arrythmias (n = 0). A total of 11 patients died within 7 days of triple antiemetic therapy. Ten of the 11 deaths were determined to not be from the triple antiemetic. One patient died at home within 24 hours of the procedure of an unknown cause (n = 1).

CONCLUSIONS AND RELEVANCE

No episodes of TdP were identified in patients receiving triple antiemetic therapy perioperatively, though the cause of death in 1 patient could not be determined. This suggest that low-dose triple antiemetic therapy is low risk for the development of TdP.

Implementation of preemptive DNA sequence-based pharmacogenomics testing across a large academic medical center: The Mayo-Baylor RIGHT 10K Study

PURPOSE

The Mayo-Baylor RIGHT 10K Study enabled preemptive, sequence-based pharmacogenomics (PGx)-driven drug prescribing practices in routine clinical care within a large cohort. We also generated the tools and resources necessary for clinical PGx implementation and identified challenges that need to be overcome. Furthermore, we measured the frequency of both common genetic variation for which clinical guidelines already exist and rare variation that could be detected by DNA sequencing, rather than genotyping.

METHODS

Targeted oligonucleotide-capture sequencing of 77 pharmacogenes was performed using DNA from 10,077 consented Mayo Clinic Biobank volunteers. The resulting predicted drug response-related phenotypes for 13 genes, including CYP2D6 and HLA, affecting 21 drug-gene pairs, were deposited preemptively in the Mayo electronic health record.

RESULTS

For the 13 pharmacogenes of interest, the genomes of 79% of participants carried clinically actionable variants in 3 or more genes, and DNA sequencing identified an average of 3.3 additional conservatively predicted deleterious variants that would not have been evident using genotyping.

CONCLUSION

Implementation of preemptive rather than reactive and sequence-based rather than genotype-based PGx prescribing revealed nearly universal patient applicability and required integrated institution-wide resources to fully realize individualized drug therapy and to show more efficient use of health care resources.

Anticoagulation in COVID-19: A Systematic Review, Meta-analysis, and Rapid Guidance From Mayo Clinic

A higher risk of thrombosis has been described as a prominent feature of coronavirus disease 2019 (COVID-19). This systematic review synthesizes current data on thrombosis risk, prognostic implications, and anticoagulation effects in COVID-19. We included 37 studies from 4070 unique citations. Meta-analysis was performed when feasible. Coagulopathy and thrombotic events were frequent among patients with COVID-19 and further increased in those with more severe forms of the disease. We also present guidance on the prevention and management of thrombosis from a multidisciplinary panel of specialists from Mayo Clinic. The current certainty of evidence is generally very low and continues to evolve.

Intravenous metoprolol versus diltiazem for rate control in noncardiac, nonthoracic postoperative atrial fibrillation

BACKGROUND

Little guidance exists on effective management of postoperative atrial fibrillation (POAF) following noncardiac, nonthoracic (NCNT) surgery.

OBJECTIVES

The purpose of this study was to identify whether a difference exists between intravenous (IV) metoprolol and diltiazem when used to achieve hemodynamically stable rate control in POAF following NCNT surgery.

METHODS

This retrospective cohort study examined critically ill adult surgical patients experiencing POAF with rapid ventricular response. Inclusion in the metoprolol or diltiazem treatment group was determined by the initial rate control agent chosen by the prescriber. The primary end point was hemodynamically stable rate control, defined by heart rate (HR) <110 beats/min and blood pressure >90 mm Hg, maintained for 6 hours.

MAIN RESULTS

Patients on metoprolol (n = 66) and diltiazem (n = 55) were similar in age, comorbidities, surgical procedure distribution, acuity of illness, and home rate and rhythm control medications continued during hospitalization; 76% of diltiazem-treated patients achieved hemodynamically stable rate control, compared with only 53% of those receiving metoprolol (P = .005). Safety end points were similar between groups, including the portion requiring a new vasopressor or fluid bolus for hemodynamic support.

CONCLUSIONS

In NCNT surgery, patients with POAF, IV diltiazem more effectively controlled HR and hemodynamics compared with metoprolol. Results warrant further research into optimal medical management of POAF in this population using these 2 agents.

Rapid-sequence intubation: a review of the process and considerations when choosing medications

OBJECTIVE

To summarize published data regarding the steps of rapid-sequence intubation (RSI); review premedications, induction agents, neuromuscular blockers (NMB), and studies supporting use or avoidance; and discuss the benefits and deficits of combinations of induction agents and NMBs used when drug shortages occur.

DATA SOURCE

A search of Medline databases (1966-October 2013) was conducted.

STUDY SELECTION AND DATA EXTRACTION

Databases were searched using the terms rapid-sequence intubation, fentanyl, midazolam, atropine, lidocaine, phenylephrine, ketamine, propofol, etomidate thiopental, succinylcholine, vecuronium, atracurium, and rocuronium. Citations from publications were reviewed for additional references.

DATA SYNTHESIS

Data were reviewed to support the use or avoidance of premedications, induction agents, and paralytics and combinations to consider when drug shortages occur.

CONCLUSIONS

RSI is used to secure a definitive airway in often uncooperative, nonfasted, unstable, and/or critically ill patients. Choosing the appropriate premedication, induction drug, and paralytic will maximize the success of tracheal intubation and minimize complications.

Effect of body mass index on bleeding frequency and activated partial thromboplastin time in weight-based dosing of unfractionated heparin: a retrospective cohort study

OBJECTIVE

To assess bleeding and activated partial thromboplastin time (APTT) in relation to body mass index (BMI) in patients prescribed weight-based dosing of intravenous unfractionated heparin (UFH) for cardiac indications without a maximum (dose-capped) initial bolus or capped initial infusion rate.

PATIENTS AND METHODS

Consecutive patients admitted to an academic medical center from February 1, 2002, through November 31, 2003, who were treated with a UFH nomogram consisting of a 60-U/kg intravenous bolus plus an initial continuous intravenous infusion of 12 U/kg hourly and titrated to a goal APTT range corresponding to thromboplastin-adjusted target heparin levels of 0.3 to 0.7 U/mL by anti-Xa assay were evaluated for this retrospective cohort study. Patients were excluded if they concomitantly received a fibrinolytic, glycoprotein IIb/IIIa inhibitor, or any other antithrombotic agent (except warfarin). Study patients were divided into quartiles by BMI.

RESULTS

Of the 1054 patients included in the study, 807 (76.6%) had an initial bolus dose higher than 4000 U, and 477 (45.3%) had an initial infusion rate higher than 1000 U/h. Despite a significant difference among BMI quartiles in proportion of supratherapeutic first APTT values (P<.001), no statistically significant difference was found in bleeding frequency (P=.26) or frequency of first APTT within the goal range (P=.27). Logistic regression analyses revealed that BMI was not a significant predictor of bleeding or first APTT within the goal range.

CONCLUSION

We did not find any difference in the proportion of first APTT values in the goal range or an increased risk of bleeding in obese patients treated with UFH without a capped initial dose. Our data demonstrate the safe use of weight-based UFH without a capped initial bolus dose or capped initial infusion rate in patients with medical cardiac conditions.

Comparison of a nurse initiated insulin infusion protocol for intensive insulin therapy between adult surgical trauma, medical and coronary care intensive care patients

Background

Sustained hyperglycemia is a known risk factor for adverse outcomes in critically ill patients. The specific aim was to determine if a nurse initiated insulin infusion protocol (IIP) was effective in maintaining blood glucose values (BG) within a target goal of 100–150 mg/dL across different intensive care units (ICUs) and to describe glycemic control during the 48 hours after protocol discontinuation.

Methods

A descriptive, retrospective review of 366 patients having 28,192 blood glucose values in three intensive care units, Surgical Trauma Intensive Care Unit (STICU), Medical (MICU) and Coronary Care Unit (CCU) in a quaternary care hospital was conducted. Patients were > 15 years of age, admitted to STICU (n = 162), MICU (n = 110) or CCU (n = 94) over 8 months; October 2003-June 2004 and who had an initial blood glucose level > 150 mg/dL. We summarized the effectiveness and safety of a nurse initiated IIP, and compared these endpoints among STICU, MICU and CCU patients.

Results

The median blood glucose values (mg/dL) at initiation of insulin infusion protocol were lower in STICU (188; IQR, 162–217) than in MICU, (201; IQR, 170–268) and CCU (227; IQR, 178–313); p < 0.0001. Mean time to achieving a target glucose level (100–150 mg/dL) was similar between the three units: 4.6 hours in STICU, 4.7 hours in MICU and 4.9 hours in CCU (p = 0.27). Hypoglycemia (BG < 60 mg/dL) occurred in 7% of STICU, 5% of MICU, and 5% of CCU patients (p = 0.85). Protocol violations were uncommon in all three ICUs. Mean blood glucose 48 hours following IIP discontinuation was significantly different for each population: 142 mg/dL in STICU, 167 mg/dL in MICU, and 160 mg/dL in CCU (p < 0.0001).

Conclusion

The safety and effectiveness of nurse initiated IIP was similar across different ICUs in our hospital. Marked variability in glucose control after the protocol discontinuation suggests the need for further research regarding glucose control in patients transitioning out of the ICU.

Oxygen Therapeutics: Oxygen Delivery Without Blood

Nearly 14 million units of packed red blood cells are transfused in the United States each year. According to the U.S. Department of Health and Human Services, in 1999, 6% of hospitals reported a shortage of blood, resulting in the cancellation or postponement of surgical procedures. The many limitations and risks of transfusions of packed red blood cells in critically ill patients have facilitated interest in developing alternative agents for oxygen delivery. Over the past few decades, safe and effective substitutes have been in development. However, no currently approved agent provides both oxygen transport and volume in place of packed red blood cells. Oxygen therapeutic products have several advantages compared with packed red blood cells, including a prolonged shelf-life, lack of a cross-matching requirement, and minimal infectious risks or concerns about immunogenicity. Hemoglobin-based oxygen carriers and perfluorocarbons are being developed. Two products are undergoing clinical trials. Polyheme is undergoing a phase III study in trauma patients, and Hemopure is being evaluated in a phase II study in patients undergoing cardiopulmonary bypass surgery. A third product (Hemolink) was being evaluated in a phase III study in patients undergoing coronary artery bypass grafting surgery; however, the trial was suspended. In addition, several other hemoglobin-based oxygen carriers are in the preclinical stages. Oxygen therapeutics have several potential clinical applications in the management of perioperative blood loss, trauma, acute normovolemic hemodilution, traumatic brain injury, and blood requirements in patients who refuse or have contraindications to transfusions of red blood cells.

Comparing intravenous amiodarone or lidocaine, or both, outcomes for inpatients with pulseless ventricular arrhythmias*

OBJECTIVE

To compare survival rates of patients with in-hospital cardiac arrest due to pulseless ventricular tachycardia/ventricular fibrillation treated with lidocaine, amiodarone, or amiodarone plus lidocaine.

DESIGN

Multicenter retrospective medical record review.

SETTING

Three academic medical centers in the United States.

PATIENTS

Hospitalized adult patients who received amiodarone, lidocaine, or a combination for pulseless ventricular tachycardia/ventricular fibrillation between August 1, 2000, and July 31, 2002.

MEASUREMENTS AND MAIN RESULTS

Data were collected according to the Utstein style. In-hospital proportion of patients living at 24 hrs and discharge were analyzed using chi-square analysis. Of the 605 patient medical records reviewed, 194 met criteria for inclusion (n=79 for lidocaine, n=74 for amiodarone, n=41 for combination). Available data showed no difference in proportion of patients alive 24 hrs post-cardiac arrest (p=.39). Cox regression analysis indicated a decreased likelihood of survival in patients with pulseless ventricular tachycardia/ventricular fibrillation as an initial rhythm as compared with those who presented with bradycardia followed by pulseless ventricular tachycardia/ventricular fibrillation and in those patients who received amiodarone as compared with lidocaine. However, only 14 patients (25%) in the amiodarone group received the recommended initial 300-mg intravenous bolus, and amiodarone was administered an average of 8 mins later in the code compared with lidocaine (p<.001).

CONCLUSIONS

These results generate the hypothesis that inpatients with cardiac arrest may have different benefits from lidocaine and amiodarone than previously demonstrated. Inadequate dosing and later administration of amiodarone in the code were two confounding factors in this study. Prospective studies evaluating these agents are warranted.

Agreement Between Bedside Blood and Plasma Glucose Measurement in the ICU Setting

STUDY OBJECTIVE

To assess the agreement between bedside glucose (bGlu) measurements and laboratory plasma glucose (pGlu) measurements in the ICU setting.

DESIGN

Retrospective study.

SETTING

ICU of a tertiary academic medical center.

PATIENTS

One hundred ninety-seven patients admitted to the ICU from January through December 2002 who underwent 816 simultaneous bGlu and pGlu measurements.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

To calculate the agreement between the two methods of glucose measurement, the mean difference was obtained, and the limits of the agreement were calculated as the mean difference +/- 2 SDs. On 767 occasions, the mean bGlu was 159 mg/dL and the mean pGlu was 151 mg/dL (p < 0.001). The mean difference between the two techniques was 7.9 mg/dL (SD, 17.6 mg/dL), and the limits of agreement were + 43.1 and -27.2. On 31 occasions, the bGlu was reported as > 400 mg/dL, and in these cases the mean pGlu was 423 mg/dL (range, 300 to 900 mg/dL). On 18 occasions, the bGlu was reported as < 50 mg/dL, and in these cases the mean pGlu was 66.9 mg/dL (range, 13 to 198 mg/dL).

CONCLUSIONS

On average, bGlu provides a reasonable estimate for pGlu. However, for the individual patient, bGlu gives an unreliable estimate for pGlu. All of those taking care of critically ill patients should be aware of the limitations of bedside glucometry.

Effectiveness of a Computerized System for Intravenous Heparin Administration: Using Information Technology to Improve Patient Care and Patient Safety

To overcome errors in prescribing, calculating doses, and monitoring intravenous heparin, a computerized heparin nomogram system (HepCare) was developed to improve heparin safety using interactive cues between the prescriber, nurse, pharmacist, and the laboratory. The frequency of deviations decreased from 0.5 per patient before HepCare with the protocol to 0.006 per patient with HepCare and the protocol. The goal activated partial thromboplastin time results of the HepCare system (group I) were compared with patients who were not treated using the HepCare system (group II). There was a higher mean percentage of activated partial thromboplastin times within goal range in group I vs. II-44% vs. 27% (p<0.01). There were reminders of a drop in platelet count in 6% of patients, hemoglobin drop in 0.7%, and validation activated partial thromboplastin time values in 7% of patients by HepCare. HepCare-guided intravenous heparin resulted in significant improvements in safety, quality assurance, and targeted activated partial thromboplastin time values.

Hospital rules-based system: The next generation of medical informatics for patient safety

PURPOSE

The hospital rules-based system (HRBS) and its subsystems at a major medical center are described.

SUMMARY

The HRBS was implemented at the Mayo Clinic to rapidly identify and communicate crucial information to the clinician in order to optimize patient care. The system also enhances workload efficiency and improves documentation and communication. The system is used by the infectious-diseases division, pharmacy services, nutritional support services, infection control, and the nursing department. The six HRBS subsystems are Web-based programs that share a common structural design and integrate computerized information from multiple institutional databases. The integrated data are presented in a user-friendly format that improves the efficiency of data retrieval. Information, such as monitoring notes and intervention information, can be entered for specific patients. The subsystems use rules designed to detect suboptimal therapy or monitoring and identify opportunities for cost savings in a timely manner.

CONCLUSION

The HRBS enhances the identification of drug-related problems while optimizing patient care and improving communication and efficiency at a major medical center.

Interaction Between Dexamethasone Treatment and the Corticotropin Stimulation Test in Septic Shock

OBJECTIVE:

To review dexamethasone interaction with corticotropin stimulation testing, particularly as it applies to treating septic shock.

DATA SOURCES:

Pertinent literature was identified through MEDLINE (1966–February 2004) using combinations of the key words dexamethasone, adrenocorticotropic hormone stimulation, and pretreat. Only articles written in the English language and evaluating human subjects were considered. Reference lists of identified articles were reviewed for additional citations.

DATA SYNTHESIS:

Accurate interpretation of the corticotropin stimulation test is important to identify patients with septic shock who may benefit from corticosteroid supplementation. In healthy volunteers, short-term dexamethasone administration prior to the corticotropin stimulation test may depress the baseline cortisol level, but does not inhibit the response to the corticotropin challenge. This may result in a slight increase in the difference between baseline and post-stimulation values.

CONCLUSIONS:

In 2 small trials in healthy adults, short-term, low-dose dexamethasone pretreatment decreased baseline cortisol levels, but values following corticotropin stimulation were unaffected. Accordingly, caution in interpreting corticotropin stimulation test results is warranted. However, the application of the findings from these studies to patients with septic shock is difficult, given the important differences in physiology between normal and septic patients. As of December 29, 2004, a dexamethasone dose >2 mg or prolonged dexamethasone therapy (>2 days, totaling 4 mg) preceding corticotropin stimulation has not been studied in any population.

Dosing of unfractionated heparin in acute coronary syndromes

Although the use of low-molecular-weight heparins for treatment of acute coronary syndromes (ACS) has increased in recent years, unfractionated heparin (UFH) remains the drug of choice for many patients and institutions. One reason is that this agent is safe for patients with renal dysfunction as well as those who undergo percutaneous coronary intervention or coronary artery bypass graft. The use of UFH is complicated by the increased risk of bleeding due to concurrent administration of numerous antiplatelet drugs in most patients with ACS, the limited data regarding ideal therapeutic range, and the wide variability of patient response. Knowledge regarding the optimal therapeutic range and how to achieve it efficiently may enable clinicians to improve clinical outcomes in patients with ACS. We reviewed and analyzed the available evidence to clarify how to best manage UFH therapy in patients with ACS. Current data support the use of a lower and narrower therapeutic range for patients with ACS than the range that is used for venous thromboembolism. Many factors in addition to weight affect patient response to UFH, including age, sex, diabetes mellitus, smoking status, and obesity.

Fixed-dose vasopressin compared with titrated dopamine and norepinephrine as initial vasopressor therapy for septic shock

STUDY OBJECTIVE

To investigate the early blood pressure effects of vasopressin compared with titrated catecholamines as initial drug therapy in patients with septic shock.

DESIGN

Retrospective cohort, single-center study.

SETTING

Intensive care units at the Mayo Clinic, Rochester, Minnesota.

PATIENTS

Fifty, 49, and 51 intensive care patients treated initially with vasopressin, norepinephrine, and dopamine, respectively.

INTERVENTION

Patients received either intravenous infusion of fixed-dose vasopressin 0.04 U/minute or titrated infusions of norepinephrine or dopamine for low systemic arterial pressures.

MEASUREMENTS AND MAIN RESULTS

Patients treated with vasopressin, norepinephrine, and dopamine were similar in all measured characteristics except for their score on the Acute Physiology and Chronic Health Evaluation (APACHE) III (dopamine > vasopressin, p=0.049), renal comorbidities (dopamine > vasopressin, p=0.03) and baseline mean arterial pressure (MAP) (norepinephrine < vasopressin, p=0.005 or dopamine < vasopressin, p=0.05). In all patients, MAP 1 hour before and 1 hour afte intervention, heart rate, and systolic blood pressure were obtained. No treatment differences were identified in achieving postvasopressin MAP after adjusting for APACHE III score, renal dysfunction, and baseline MAP. In patients receiving vasopressin, 28-day mortality was 52%, similar to those receiving norepinephrine (65%, p=0.28) and dopamine (60%, p=0.53).

CONCLUSION

Initial, fixed-dose vasopressin infusions increased MAP to 70 mm Hg or greater at 1 hour in intensive care patients with septic shock, similar to titrated norepinephrine or dopamine. Fixed-dose vasopressin appears appropriate as an alternative agent for hemodynamic support in patients with septic shock.

A study of a weight-adjusted aprotinin dosing schedule during cardiac surgery

Aprotinin is effective during cardiac surgery for reducing blood loss and transfusion requirements, but it is expensive. Aprotinin is usually administered to adults according to a fixed protocol regardless of the patient's weight. We previously developed a weight-based dosing protocol for aprotinin. The purpose of this prospective observational study was to determine aprotinin levels in four patient groups (n = 10 each) using the new weight-based aprotinin dosing schedule that should achieve concentrations over 100, 150, 200, and 250 kallikrein inhibitory units/mL compared with full-dose aprotinin regimen (n = 10) by a simple functional aprotinin assay. There was no difference in patient demographic or surgical variables among groups. There was less within patient variation in plasma aprotinin concentrations over time in the new weight-based aprotinin dosing schedule groups compared with the full-dose aprotinin regimen group (P < 0.02 for all comparisons). The mean plasma aprotinin concentration achieved with the new weight-based aprotinin dosing schedule was similar to the desired concentrations, but we were unable to reduce between-patient variability in aprotinin concentrations.

IMPLICATIONS

The current dosing schedule for aprotinin results in a large variation in aprotinin plasma concentrations between patients and a large variation within each patient over time. A new weight-based dosing schedule reduced variation of aprotinin concentration over time, but was unable to reduce between-patient variability in aprotinin concentration.

Analgesic agents. Pharmacology and application in critical care

Evaluation of analgesic agents is multifactorial. The authors know of no direct comparisons among the choices in analgesic agents that suggest one therapy over another in global outcomes such as mortality or morbidity. Therefore, until further outcome differentiation between agents is proved, understanding the primary difference of delivery routes, mechanisms of action, pharmacokinetics, and adverse effects serves as the best guide for selecting the appropriate agent for each patient.

Plasma tranexamic acid concentrations during cardiopulmonary bypass

Although tranexamic acid is used to reduce bleeding after cardiac surgery, there is large variation in the recommended dose, and few studies of plasma concentrations of the drug during cardiopulmonary bypass (CPB) have been performed. The plasma tranexamic acid concentration reported to inhibit fibrinolysis in vitro is 10 microg/mL. Twenty-one patients received an initial dose of 10 mg/kg given over 20 min followed by an infusion of 1 mg. kg(-1). h(-1) via a central venous catheter. Two patients were removed from the study secondary to protocol violation. Perioperative plasma tranexamic acid concentrations were measured with high-performance liquid chromatography. Plasma tranexamic acid concentrations (microg/mL; mean +/- SD [95% confidence interval]) were 37.4 +/- 16.9 (45.5, 29.3) after bolus, 27.6 +/- 7.9 (31.4, 23.8) after 5 min on CPB, 31.4 +/- 12.1 (37.2, 25.6) after 30 min on CPB, 29.2 +/- 9.0 (34.6, 23.8) after 60 min on CPB, 25.6 +/- 18.6 (35.1, 16.1) at discontinuation of tranexamic acid infusion, and 17.7 +/- 13.1 (24.1, 11.1) 1 h after discontinuation of tranexamic acid infusion. Four patients with renal insufficiency had increased concentrations of tranexamic acid at discontinuation of the drug. Repeated-measures analysis revealed a significant main effect of abnormal creatinine concentration (P = 0.02) and time (P < 0.001) on plasma tranexamic acid concentration and a significant time x creatinine concentration interaction (P < 0.001).

IMPLICATIONS

A 10 mg/kg initial dose of tranexamic acid followed by an infusion of 1 mg.kg(-1).h(-1)produced plasma concentrations throughout the cardiopulmonary bypass period sufficient to inhibit fibrinolysis in vitro. The dosing of tranexamic acid may require adjustment for renal insufficiency.

Plasma aprotinin concentrations during cardiac surgery: full- versus half-dose regimens

Aprotinin is an effective but expensive drug used during cardiac surgery to reduce blood loss and transfusion requirements. Currently, aprotinin is administered to adults according to a fixed protocol regardless of the patient's weight. The purpose of this study was to determine aprotinin levels in patients receiving full- and half-dose aprotinin regimens by a simple functional aprotinin assay and to design a more individualized aprotinin dosage regimen for cardiac surgical patients. The mean plasma aprotinin concentration peaked 5 min after the initiation of cardiopulmonary bypass (full 401 +/- 92 KIU/mL, half 226 +/- 56 KIU/mL). The mean plasma aprotinin concentration after 60 min on cardiopulmonary bypass was less (full 236 +/- 81 KIU/mL, half 160 +/- 63 KIU/mL). There was large variation in the aprotinin concentration among patients. A statistically significant correlation was found between aprotinin concentration and patient weight (r(2) = 0.67, P < 0.05).

IMPLICATIONS

The current dosing schedule for aprotinin results in a large variation in aprotinin plasma concentrations among patients and a large variation within each patient over time. We combined the information provided by our study with that of a previous pharmacokinetic study to develop a potentially improved, weight-based, dosing regime for aprotinin.

Necrotizing pancreatitis: pathophysiology, diagnosis, and acute care management

Severe acute necrotizing pancreatitis is a disease that is caused by premature activation of pancreatic enzymes. Cytokine release contributes to systemic manifestations such as systemic inflammatory response syndrome (SIRS), multiple organ dysfunction syndrome (MODS), adult respiratory distress syndrome (ARDS), and sepsis. Diagnosis is based on a history of abdominal pain, laboratory values such as serum amylase and lipase levels, and CT scan. Medical management focuses on fluid and electrolyte balance, antibiotic therapy, pain control, and decreasing systemic complications. Surgery is indicated when infectious pancreatic necrosis has been identified. This article addresses incidence and etiology; pathophysiology; clinical manifestations; diagnostics; and medical and surgical patient care management.