Cost comparisons of pharmacological strategies in open-heart surgery

Clinical and economic impact of substituting dexmedetomidine for propofol due to a US drug shortage: examination of coronary artery bypass graft patients at an urban medical centre

BACKGROUND

Propofol has reduced healthcare costs in coronary artery bypass graft (CABG) surgery patients by decreasing post-operative duration of mechanical ventilation. However, the US shortage of propofol necessitated the use of alternative agents.

OBJECTIVE

This study sought to evaluate clinical and economic implications of substituting dexmedetomidine for propofol in patients undergoing CABG surgery.

METHODS

This was a retrospective cohort study. Patients undergoing isolated, elective CABG surgery and sedated with either propofol or dexmedetomidine during the study period were included. The cohorts were matched 1:1 based on important characteristics. The primary outcome was the number of patients achieving a post-operative duration of mechanical ventilation ≤6 h. Secondary outcomes were post-operative intensive care unit (ICU) length of stay (LOS) ≤48 h, total post-operative LOS ≤5 days, the need for adjunctive opioid therapy and associated cost savings. Variables recorded included patient demographics, co-morbid medical conditions, health risks, sedation drug doses, post-operative medical complications and sedation-related adverse events. Univariate and multivariate analyses were completed to examine the relationship between these covariates and post-operative LOS. The cost analysis consisted of examination of the net financial benefit (or cost) of choosing dexmedetomidine versus propofol in the study population, with utilisation observed in the study converted to costs using institutional data from the Premier database.

RESULTS

Eighty-four patients were included, with 42 patients per cohort. Mechanical ventilation duration ≤6 h was achieved in 24 (57.1 %) versus 7 (16.7 %) in the dexmedetomidine and propofol cohorts, respectively (p < 0.001). More patients treated with dexmedetomidine achieved ICU LOS ≤48 h (p < 0.05) and total hospital LOS ≤5 days (p < 0.05), as compared with the propofol group. Multivariate analysis revealed that having one or more post-operative medical complication was the most significant predictor of increased post-operative LOS, whereas choosing dexmedetomidine was also significant in terms of reduced post-operative LOS. The estimated net financial benefit of choosing dexmedetomidine versus propofol was US$2,613 per patient (year 2012 value).

CONCLUSIONS

Findings suggest that use of dexmedetomidine as an alternative to propofol for sedation of CABG patients post-operatively contributes to reduced mechanical ventilation time, ICU LOS and post-operative LOS. Higher drug costs resulting from the propofol shortage were offset by savings in post-operative room and board costs. Additional savings may be possible by preventing medical complications to the extent possible.

Inflammation effects on the electrical properties of atrial tissue and inducibility of postoperative atrial fibrillation

BACKGROUND

Atrial fibrillation is the most common complication after cardiac surgery. Postoperative atrial fibrillation (PAF) has been shown to increase length of stay, morbidity, and mortality. Because the clinical behavior of PAF parallels that of inflammation following surgery, we investigated the effect of the inflammatory mediator arachidonic acid on the electrical behavior of normal atrial tissue in vitro and assessed the efficacy of the topical application of anti-inflammatory drugs at suppressing PAF in an animal model.

METHODS

To study changes in electrical behavior from inflammation, the conduction properties of six normal canine right atrial appendages were quantified as a function of the direction of impulse propagation with and without 80 mum arachidonic acid. To study the effect of topical anti-inflammatory drugs, 24 adult mongrel dogs were prepared according to the model of sterile talc pericarditis. Nine dogs received talc alone (T), seven received talc combined with 600 mg ibuprofen (T + I), and eight received talc combined with 10 mg methylprednisolone (T + M). Three days following preparation, programmed electrical stimulation was performed to quantify conduction characteristics and to attempt the induction of atrial fibrillation (AF).

RESULTS

In vitro, arachidonic acid produced an anisotropic and rapidly reversible 36.1 +/- 3.4% (P = 0.01) decrease in conduction velocity transverse to the long axis only. In vivo, both ibuprofen and methylprednisolone significantly reduced the incidence of sustained AF (from 56 to 0% T + I and 12% T + M, respectively, P = 0.02). No differences in conduction velocities or refractory periods were seen during sinus rhythm among the groups.

CONCLUSIONS

Acute inflammation as mimicked by arachidonic acid slows conduction anisotropically, mainly transverse to the long axis of the atrial myocardial fibers. This may set the stage for reentry. Preventing inflammation in vivo by the topical application of anti-inflammatory drugs supports this hypothesis, suggesting a possible role for inflammation in the genesis of postoperative atrial fibrillation and shedding light on the mechanism underlying PAF.

Factor V Leiden and perioperative risk

Factor V Leiden (FVL) is the most common known inherited cause of thrombophilia; it is present in approximately 5% of the Caucasian population. Although the risk of venous thrombosis associated with this polymorphism in various medical settings is well described, its effect on perioperative risk is only beginning to be explored. Specifically, there are few studies addressing the potential risks of FVL in the surgical population, in which both hemorrhagic and thrombotic complications convey substantial clinical and economic significance. There are speculations and unproven hypotheses regarding FVL in this population, and these therefore highlight the need to comprehensively address this issue. This review will describe the physiology of the FVL mutation, briefly clarify its risk in the nonsurgical setting, and assess current data regarding FVL in noncardiac and cardiac surgery. Finally, a summary of current clinical evidence and a plan for more detailed investigation of this potentially significant risk factor will be proposed.