Antiepileptic drugs in critically ill patients

BACKGROUND

The incidence of seizures in intensive care units ranges from 3.3% to 34%. It is therefore often necessary to initiate or continue anticonvulsant drugs in this setting. When a new anticonvulsant is initiated, drug factors, such as onset of action and side effects, and patient factors, such as age, renal, and hepatic function, should be taken into account. It is important to note that the altered physiology of critically ill patients as well as pharmacological and nonpharmacological interventions such as renal replacement therapy, extracorporeal membrane oxygenation, and target temperature management may lead to therapeutic failure or toxicity. This may be even more challenging with the availability of newer antiepileptics where the evidence for their use in critically ill patients is limited.

MAIN BODY

This article reviews the pharmacokinetics and pharmacodynamics of antiepileptics as well as application of these principles when dosing antiepileptics and monitoring serum levels in critically ill patients. The selection of the most appropriate anticonvulsant to treat seizure and status epileptics as well as the prophylactic use of these agents in this setting are also discussed. Drug-drug interactions and the effect of nonpharmacological interventions such as renal replacement therapy, plasma exchange, and extracorporeal membrane oxygenation on anticonvulsant removal are also included.

CONCLUSION

Optimal management of antiepileptic drugs in the intensive care unit is challenging given altered physiology, polypharmacy, and nonpharmacological interventions, and requires a multidisciplinary approach where appropriate and timely assessment, diagnosis, treatment, and monitoring plans are in place.

Impact of intraoperative cefazolin on postoperative seizures after elective repair of unruptured cerebral aneurysm

PURPOSE

The impact of intraoperative cefazolin on postoperative seizures after elective repair of an unruptured cerebral aneurysm was evaluated.

METHODS

Chart review of a prospectively accrued database was performed for patients admitted from January 1, 2003, through December 31, 2013. Patients were included in the study if they underwent elective repair of an unruptured aneurysm with surgical clipping or wrapping. The primary objective was to determine if the use of cefazolin increased patients' odds of having a seizure within six hours of surgical intervention. Univariate comparisons were conducted on all variables for patients who received cefazolin and patients who were treated with other antibiotics. Multivariable logistic regression was performed to assess the impact of cefazolin administered intraoperatively on postoperative seizures, while accounting for other covariates.

RESULTS

Of the 520 patients included, 53 (10.2%) patients developed seizures within six hours after surgery. A total of 439 (84.4%) patients received cefazolin intraoperatively. There were no differences in baseline characteristics between the patients who received cefazolin compared with those who did not. The frequency of seizures did not significantly differ between patients treated with cefazolin versus other antibiotics (11.2% versus 4.9%, respectively; p = 0.08). Multivariable regression revealed that the use of cefazolin did not increase the odds of having a seizure postoperatively compared with patients treated with other antibiotics (odds ratio, 2.4; 95% confidence interval, 0.82-7.15).

CONCLUSION

No relationship was found between the intraoperative use of cefazolin and the development of seizures during the six hours after the repair of unruptured cerebral aneurysms.

Elevating pharmacists' scope of practice through a health-system clinical privileging process

PURPOSE

The privileging of pharmacists for clinical activities and the impact that privileging has on enhancing the scope of pharmacy practice in health systems are reviewed.

SUMMARY

Health-system pharmacists or pharmacy leaders must gain a thorough understanding of the credentialing and privileging process as they broaden their scope of practice. Clinical privileging affords an expanded scope of practice that is recognized at the institutional level and formally elevates the pharmacist to that of a nonphysician provider. The installation of privileging processes is expected to take many months to complete for individual institutions and should begin now in anticipation of provider status. Model institutions, including Truman Medical Centers, Johns Hopkins Hospital, and The Ohio State University Wexner Medical Center, are highlighted in this article and provide their individual approach to clinical privileging that can be applied to other institutions. The development and evaluation of these programs have given valuable insight into how this individual approach translates to health systems across the country and how the pharmacy profession can continue to unite to convey the value of pharmacists in improving patient care.

CONCLUSION

In preparation for the potential approval of pharmacist provider status across the United States, it is essential that pharmacists are privileged by the medical staff at their respective institution. Clinical privileges must be strategically developed with a focus on cost and quality aims and meeting the needs of patients. Implementation and maintenance of high-performing pharmacy privileging programs require both successful leadership and management skills and an understanding of the interprofessional nature of healthcare.

Central Nervous System Infections in the Critically Ill

Central nervous system (CNS) infections are frequently encountered in the intensive care unit setting and are a significant source of morbidity and mortality. The constantly changing trends in microbial resistance, as well as the pharmacokinetic difficulties in providing effective concentrations of antimicrobials at the site of infection represent a unique challenge to clinicians. Achievement of a successful outcome in patientswith CNS infections is reliant on eradication of the offending pathogen and management of any neurologic complications. This requires an anatomic and physiologic understanding of the different types of CNS infection, diagnostic strategies, associated complications, causative organisms, and the principles that govern drug distribution into the CNS. This article serves as a review of the epidemiology, pathophysiology, diagnosis, and treatment options for a variety of CNS infections, with a focus on those commonly encountered in an intensive care setting.

Rhabdomyolysis with Concurrent Atorvastatin and Diltiazem

OBJECTIVE:

To report a case of rhabdomyolysis and acute hepatitis associated with the coadministration of atorvastatin and diltiazem.

CASE SUMMARY:

A 60-year-old African American man with a significant past medical history presented to the emergency department with acute renal failure secondary to rhabdomyolysis. In addition, liver enzymes were elevated to greater than 3 × normal. The only change in medication was the initiation of diltiazem 3 weeks earlier for atrial fibrillation to a complicated medication regimen that included atorvastatin.

DISCUSSION:

Rhabdomyolysis has been reported in patients receiving hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors when coadministered with agents that may inhibit their metabolism. Atorvastatin is the most potent of this class of agents currently available and is commonly used in the treatment of hyperlipidemia. Rhabdomyolysis resulting from the drug interaction between diltiazem and other HMG-CoA reductase inhibitors has been described in the literature. However, no report has specifically associated this adverse event with atorvastatin and diltiazem. We describe a patient with a complex medication regimen who was admitted for rhabdomyolysis and accompanying acute renal failure, along with acute hepatitis, thought to be secondary to a drug interaction between atorvastatin and diltiazem.

CONCLUSIONS:

While optimizing the patient's lipid profile should be the primary factor in choosing one statin over another, the potential for drug interactions requires close attention. All patients beginning HMG-CoA reductase inhibitor therapy should be counseled regarding the signs and symptoms of muscle injury; particular attention should be paid to those patients who are taking medications that may interact.

Comparison of free fraction serum valproic acid concentrations between inpatients and outpatients

PURPOSE

The differences in free fraction serum valproic acid concentrations between inpatients and outpatients were compared, and factors associated with therapeutic discordance were evaluated.

METHODS

This retrospective, single-center, cross-sectional study included patients with both a free and a total valproic acid concentration drawn within 30 minutes of each other between January 7, 2003, and June 1, 2011. Serum valproic acid concentrations were stratified by admission status (inpatient versus outpatient). In the primary analysis, for patients who had multiple paired concentrations drawn, one free valproic acid level and one total valproic acid level (i.e., one pair) were chosen at random for each inpatient. Information regarding patient demographics, laboratory data, and concomitant medication therapy was collected. Single and multivariable logistic regressions were performed to determine the odds of therapeutic discordance.

RESULTS

During the study period, inpatient concentrations were measured in 220 patients, and outpatient concentrations were measured in 41 patients. The median total valproic acid concentration in the inpatient group was significantly lower than that in the outpatient group (54 μg/mL versus 83 μg/mL, p < 0.001). The median free fraction of inpatient levels was nearly twice as high as that of outpatient levels (28.8% versus 15.5%, p < 0.001). Levels drawn in inpatients were therapeutically discordant 63% of the time compared to only 19% in outpatients (p < 0.001). Multivariable logistic regression identified low albumin as an independent risk factor for therapeutic discordance.

CONCLUSION

The median free fraction of valproic acid was significantly higher in inpatients than in outpatients. Low albumin concentration was a predictor of discordance between free and total valproic acid concentrations.

Management of bleeding and reversal strategies for oral anticoagulants: clinical practice considerations

PURPOSE

Currently available clinical data and optimal strategies for reversing oral anticoagulants in patients who are bleeding or need an urgent invasive procedure or operation are reviewed.

SUMMARY

Bleeding from oral anticoagulants, including new target-specific oral agents (TSOAs), is a common cause of morbidity and mortality, especially in elderly patients. Limited clinical data are available to guide the reversal of warfarin or TSOAs in patients who are bleeding or need an urgent invasive procedure or operation. A panel of five experts with diverse backgrounds in anticoagulation therapy, cardiology, critical care, and emergency medicine and with experience in managing complications of anticoagulation therapy was convened to develop practical strategies for managing patients receiving oral anticoagulants who are bleeding or have an urgent need for an invasive procedure. The strategies were designed to guide clinicians in the acute care setting by providing efficient and potentially effective management concepts to avoid delays in initiating treatment that could adversely affect patient outcomes. The consensus of this expert panel is summarized herein. Recommendations are based on currently available evidence from a comprehensive review of the literature and other pertinent data, along with the experience and expert opinion of the panelists.

CONCLUSION

Bleeding is a serious complication of the use of oral anticoagulants, and limited information is available to guide the reversal of warfarin or TSOAs in patients who are bleeding or are in need of an urgent invasive procedure. Use of a systematic approach to assessing and treating these patients based on available evidence and expert opinion can help avoid delays that could adversely affect patient outcomes.

Survey of transplant-related pharmacy services at large comprehensive transplant centers in the United States

CONTEXT

United Network for Organ Sharing (UNOS) 2011 bylaws and Centers for Medicare and Medicaid Services (CMS) regulations require a transplant pharmacist to be an active participant in the care of transplant patients. Transplant centers must be members in good standing with UNOS in order to perform transplants and must be certified by CMS to participate with Medicare.

OBJECTIVE

To identify characteristics of transplant-related pharmacy services at comprehensive transplant centers.

DESIGN

Survey regarding number of full-time equivalent (FTE) transplant pharmacists relative to number of annual transplants, transplant pharmacy model, roles in inpatient and clinic environments, training and specialization, funding sources, and expansion plans.Participants-Surveys were received from 14 (74%) of 19 identified centers that performed 200 to 400 kidney, liver, pancreas, simultaneous kidney/pancreas, heart, and lung transplants in 2010, representing 55 transplant pharmacists.

RESULTS

A mean of 325 transplants were performed in 2010 at the surveyed centers. The mean number of pharmacist FTEs was 4.25, which yielded a transplant-to-pharmacist ratio of 76.5. Nine centers (64%) practiced in a pharmacy specialist-only model, 12 (86%) practiced in a service-based fashion, and 10 (71%) saw patients in clinic. Fifty-four pharmacists (98%) had obtained a PharmD degree, 45 (82%) had completed 1 postgraduate year, and 28 (51%) had completed 2 postgraduate years of training. Nine centers (64%) funded FTEs solely through the pharmacy department. Ten centers (71%) plan to expand transplant pharmacist staff by a mean of 1.4 FTEs.

CONCLUSIONS

Large comprehensive transplant centers use multiple transplant pharmacists to perform patient care in the inpatient and outpatient environments. Most centers plan to expand FTEs. Further characterization of transplant pharmacists appears warranted.

Improving door-to-antibiotic time in severely septic emergency department patients

BACKGROUND

The Surviving Sepsis Campaign (SSC) guidelines recommend that broad-spectrum antibiotics be administered to severely septic patients within 3 h of emergency department (ED) admission. Despite the well-established evidence regarding the benefit of timely antibiotics, adoption of the SSC recommendation into daily clinical practice has been slow and sporadic.

STUDY OBJECTIVE

To study the impact of storing broad-spectrum antibiotics in an ED automated dispensing cabinet (ADC) on the timeliness of antibiotic administration in severely septic patients presenting to the ED.

METHODS

Retrospective observational study of timeliness of antibiotic administration in severely septic patients presenting to a community ED before and after adding broad-spectrum antibiotics to the ED ADC. Data on 56 patients before and 54 patients after the intervention were analyzed. The primary outcome measure was mean order-to-antibiotic time. Secondary outcome measures included mean door-to-antibiotic time and percentage of patients receiving antibiotics within 3 h.

RESULTS

The final analysis was on 110 patients. Order-to-antibiotic administration time was reduced by 29 min post-intervention (55 min vs. 26 min, 95% confidence interval [CI] 12.5-45.19). Mean door-to-antibiotic time was also reduced by 70 min (167 min vs. 97 min, 95% CI 37.53-102.29). The percentage of severely septic patients receiving antibiotics within 3h of arrival to the ED increased from 65% pre-intervention to 93% post-intervention (95% CI 0.12-0.42).

CONCLUSION

Storing key antibiotics in an institution's severe sepsis antibiogram in the ED ADC can significantly reduce order-to-antibiotic times and increase the percentage of patients receiving antibiotics within the recommended 3 h of ED arrival.

Sedation and Analgesia in Critically Ill Neurologic Patients

Critically ill neurologic patients can pose a challenge when it comes to providing sedation and analgesia, primarily with the balance of maintaining sedation to provide patient comfort while still allowing a neurological examination. Determination of the optimal agent requires assessment and understanding of the underlying requirement for sedation: provision of analgesia, anxiolysis, or treatment of delirium. Pharmacological options exist that can affect individual or multiple underlying sedation requirements. Numerous evaluation tools exist to monitor the efficacy of sedation as well as help clinicians titrate agents to predefined goals; these tools allow the safe administration of drugs that can otherwise have serious adverse effects. Sedation regimens must ultimately be individualized to each patient to account for differences in pharmacokinetics and dynamics of the various agents, and this is particularly true in sedating neurologically injured patients. The agents frequently used to provide sedation and analgesia in the critically ill neurologic patient will be reviewed.

Cognitive improvement during continuous sedation in critically ill, awake and responsive patients: the Acute Neurological ICU Sedation Trial (ANIST)

INTRODUCTION

Most anxiolytics and sedative regimens in the intensive care unit (ICU) impair intellectual function, reducing patient autonomy, and often add to patient morbidity. Using an ICU-validated cognitive assessment tool Adapted Cognitive Exam (ACE), we performed a comparison between dexmedetomidine (DEX) and propofol (PRO) to evaluate which sedative regimen offered the least decrement in intellectual capacity.

METHODS

This was a prospective, randomized, double-blinded study of 30 awake and intubated brain-injured (BI, n = 18) and non-BI (12) ICU patients. Each patient received fentanyl/PRO and fentanyl/DEX titrated to a calm, awake state using a crossover design. Cognitive testing was performed at each study period using the validated 100-point Hopkins ACE cognitive battery.

FINDINGS

Sedation with PRO diminished adjusted ACE scores (100-point exam) by a mean of -12.4 (95% CI -8.3 to -16.5, p < 0.001) while DEX, in contrast, improved ACE scores (6.8, 95% CI 1.2-12.4, p < 0.018). The difference in the change of ACE score between DEX versus PRO, our primary endpoint, was 19.2 (95% CI 12.3-26.1 p < 0.001) in favor of an improved ACE score on DEX. Patients with BI required less sedative, but effects of PRO and DEX on cognition were not changed. No serious adverse events occurred. Modest bradycardia was noted post hoc with DEX (-7.7 bpm, p < 0.01).

INTERPRETATION

ICU patients may be offered sedation without necessarily compromising arousal or cognition. Alleviation of anxiety and agitation can singly and effectively improve mental engagement and performance if overt forebrain dysfunction is avoided. Higher ACE scores with DEX may be a consequence of the intellect-sparing yet calming effect of this drug.

Sedation and pain management in acute neurological disease

The optimum provision of pharmacological sedation of the critically ill neurological patient requires defining the underlying etiology of agitation or need for sedation to determine the optimal agent: pain management, anxiolysis, or treatment of delirium. An appropriate regimen can then be decided upon based on the profiles of action of the several common classes of sedative agents. Methods to both evaluate the efficacy of sedation as well as titration to a predefined clinical goal are important tools toward safe administration of drugs that often have serious adverse effects. Recognition of an individualized approach is also necessary as patients will vary considerably with respect to the kinetics and pharmacodynamics of sedative therapy. The drug classes often selected for sedation in an intensive care unit will be reviewed as well as the metrics by which physicians can achieve their objectives in a safe manner.

Advances in the management of central nervous system infections in the ICU

This chapter focuses on early aggressive management of common infections of the central nervous system that require monitoring in an ICU setting. These include meningitis, encephalitis, brain and epidural abscess, subdural empyema and ventriculitis. It emphasizes priorities in evaluation and management due to increasing morbidity and mortality as a result of failure to appreciate non-specific symptoms or administer timely therapy. The emergence of organisms resistant to penicillin and cephalosporins has also further complicated the early management of bacterial meningitis. Current antimicrobial guidelines are provided along with discussion of new diagnostic and therapeutic strategies and controversial aspects of management.

Blood pressure management during acute ischaemic stroke

Control of hypertension is a well-established goal of primary stroke prevention. Management of blood pressure in patients during acute ischaemic stroke, however, is complicated by the need to maintain brain perfusion. Lowering blood pressure in the acute setting may avoid the deleterious effects of high blood pressure but may also lead to cerebral hypoperfusion and worsening of the ischaemic stroke. Little information is available from clinical trials concerning optimal blood pressure management in acute stroke. Current protocols of thrombolytic therapy require strict blood pressure control below certain prescribed limits; however, in most acute stroke patients not treated with thrombolysis, blood pressure reduction is not routinely recommended and guidelines for target blood pressures are difficult to justify. Preliminary studies, in fact, suggest that there may be a role for blood pressure elevation in the treatment of some patients with acute ischaemic stroke.

Glucocorticoid therapy in neurologic critical care

BACKGROUND

The pivotal role of inflammation and edema across the spectrum of central nervous system injury has driven extensive investigation into the therapeutic potential of glucocorticoids.

OBJECTIVE

To review the experimental and clinical data relating to the efficacy and adverse effects of glucocorticoids in conditions encountered in critical neurologic and neurosurgical illness.

DATA SOURCE

Search of MEDLINE and Cochrane databases, manual review of article bibliographies.

DATA SYNTHESIS AND CONCLUSIONS

The efficacy of glucocorticoids is well established in ameliorating edema associated with brain tumors and in improving outcome in subsets of patients with bacterial meningitis. Despite frequently encouraging experimental results, clinical trials of glucocorticoids in ischemic stroke, intracerebral hemorrhage, aneurysmal subarachnoid hemorrhage, and traumatic brain injury have not shown a definite therapeutic effect. The evidence supporting glucocorticoid therapy for spinal cord injury is controversial; however methylprednisolone continues to be widely employed in this setting.