Chronic pain recruits hypothalamic dynorphin/kappa opioid receptor signalling to promote wakefulness and vigilance.

Increased vigilance in settings of potential threats or in states of vulnerability related to pain is important for survival. Pain disrupts sleep and conversely, sleep disruption enhances pain, but the underlying mechanisms remain unknown. Chronic pain engages brain stress circuits and increases secretion of dynorphin, an endogenous ligand of the kappa opioid receptor (KOR). We therefore hypothesized that hypothalamic dynorphin/KOR signalling may be a previously unknown mechanism that is recruited in pathological conditions requiring increased vigilance. We investigated the role of KOR in wakefulness, non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep in freely moving naïve mice and in mice with neuropathic pain induced by partial sciatic nerve ligation using EEG/EMG recordings. Systemic continuous administration of U69,593, a KOR agonist, over 5 days through an osmotic minipump decreased the amount of NREM and REM sleep and increased sleep fragmentation in naïve mice throughout the light-dark sleep cycle. We used KORcre mice to selectively express a Gi-coupled designer receptor activated by designer drugs (Gi-DREADD) in KORcre neurons of the hypothalamic paraventricular nucleus, a key node of the hypothalamic-pituitary-adrenal stress response. Sustained activation of Gi-DREADD with clozapine-N-oxide delivered in drinking water over 4 days, disrupted sleep in these mice in a similar way as systemic U69,593. Mice with chronic neuropathic pain also showed disrupted NREM and total sleep that was normalized by systemic administration of two structurally different KOR antagonists, norbinaltorphimine and NMRA-140, currently in phase II clinical development, or by CRISPR/Cas9 editing of paraventricular nucleus KOR, consistent with endogenous KOR activation disrupting sleep in chronic pain. Unexpectedly, REM sleep was diminished by either systemic KOR antagonist or by CRISPR/Cas9 editing of paraventricular nucleus KOR in sham-operated mice. Our findings reveal previously unknown physiological and pathophysiological roles of dynorphin/KOR in eliciting arousal. Physiologically, dynorphin/KOR signalling affects transitions between sleep stages that promote REM sleep. Furthermore, while KOR antagonists do not promote somnolence in the absence of pain, they normalized disrupted sleep in chronic pain, revealing a pathophysiological role of KOR signalling that is selectively recruited to promote vigilance, increasing chances of survival. Notably, while this mechanism is likely beneficial in the short-term, disruption of the homeostatic need for sleep over longer periods may become maladaptive resulting in sustained pain chronicity. A novel approach for treatment of chronic pain may thus result from normalization of chronic pain-related sleep disruption by KOR antagonism.

Association between intraoperative pulmonary artery pressure and cardiovascular complications after off-pump coronary artery bypass surgery: a single-center observational study.

BACKGROUND: The impact of intraoperative pulmonary hemodynamics on prognosis after off-pump coronary artery bypass (OPCAB) surgery remains unknown. In this study, we examined the association between intraoperative vital signs and the development of major adverse cardiovascular events (MACE) during hospitalization or within 30 days postoperatively. METHODS: This retrospective study analyzed data from a university hospital. The study cohort comprised consecutive patients who underwent isolated OPCAB surgery between November 2013 and July 2021. We calculated the mean and coefficient of variation of vital signs obtained from the intra-arterial catheter, pulmonary artery catheter, and pulse oximeter. The optimal cut-off was defined as the receiver operating characteristic curve (ROC) with the largest Youden index (Youden index = sensitivity + specificity - 1). Multivariate logistic regression analysis ROC curves were used to adjust all baseline characteristics that yielded P values of < 0.05. RESULTS: In total, 508 patients who underwent OPCAB surgery were analyzed. The mean patient age was 70.0 ± 9.7 years, and 399 (79%) were male. There were no patients with confirmed or suspected preoperative pulmonary hypertension. Postoperative MACE occurred in 32 patients (heart failure in 16, ischemic stroke in 16). The mean pulmonary artery pressure (PAP) was significantly higher in patients with than without MACE (19.3 ± 3.0 vs. 16.7 ± 3.4 mmHg, respectively; absolute difference, 2.6 mmHg; 95% confidence interval, 1.5 to 3.8). The area under the ROC curve of PAP for the prediction of MACE was 0.726 (95% confidence interval, 0.645 to 0.808). The optimal mean PAP cut-off was 18.8 mmHg, with a specificity of 75.8% and sensitivity of 62.5% for predicting MACE. After multivariate adjustments, high PAP remained an independent risk factor for MACE. CONCLUSIONS: Our findings provide the first evidence that intraoperative borderline pulmonary hypertension may affect the prognosis of patients undergoing OPCAB surgery. Future large-scale prospective studies are needed to verify the present findings.

Anaesthetic management using remimazolam in a patient with severe aortic stenosis: a case report.

BACKGROUND: The administration of general anaesthesia in patients with aortic stenosis (AS) requires careful attention to haemodynamics. We used remimazolam for the induction and maintenance of anaesthesia in a woman with severe AS undergoing a total mastectomy. CASE PRESENTATION: An 81-year-old woman with severe AS was scheduled to undergo a total mastectomy. We decided to administer total intravenous anaesthesia with remimazolam to minimize haemodynamic changes. Although the patient showed transient hypotension after anaesthesia induction, the cardiac index was preserved with a low dose of continuous noradrenaline. The anaesthesia was then safely maintained without a decrease in the patient's cardiac index. CONCLUSIONS: General anaesthesia using remimazolam preserved cardiac output in this patient; therefore, remimazolam can be safely used to avoid the risk of cardiac suppression in patients with severe AS.

Relationships Between Intraoperative Hemodynamic Parameters and Delayed Hemodynamic Recovery After Valve Deployment in Transcatheter Aortic Valve Replacement.

OBJECTIVE: To determine the relationships between intraoperative hemodynamic parameters and delayed hemodynamic recovery after valve deployment and identify the predictive factors of delayed hemodynamic recovery by focusing on intraoperative hemodynamics in patients with transcatheter aortic valve replacement (TAVR). DESIGN: A retrospective study. SETTING: A single university hospital. PARTICIPANTS: Sixty-four patients who underwent elective TAVR between 2015 and 2017. INTERVENTIONS: No intervention. MEASUREMENTS AND MAIN RESULTS: The 64 patients were divided into the following 2 groups according to the time for recovery: systolic arterial pressure exceeded 90 mmHg and central venous oxygen saturation (ScvO2) exceeded 65%-delayed recovery (DR) (n = 36) group, and early recovery (ER) (n = 28) group. ScvO2 in the DR group was not lower than that in the ER group after induction of anesthesia. However, ScvO2 in the DR group gradually decreased and was lower than that in the ER group before valve deployment, despite improvement in blood pressure through the administration of vasopressor agents. CONCLUSION: ScvO2 monitoring during TAVR is useful to predict delayed recovery greater than 60 seconds after valve deployment in TAVR.

Transcatheter Aortic Valve Implantation Improves Cardiac Sympathetic Nerve Activity on 123I-Metaiodobenzylguanidine Myocardial Scintigraphy in Severe Aortic Valve Stenosis.

BACKGROUND: There is a consensus that overactivation of the cardiac sympathetic nervous system (CSN) proportionately increases the severity of heart failure and is accompanied by worse prognosis. Because it is unknown whether patients with aortic valve stenosis (AS) have similar CSN activation, we investigated the effect of transcatheter aortic valve implantation (TAVI).Methods and Results:We enrolled 31 consecutive patients with AS treated by TAVI. 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy was performed at baseline and at 2 weeks after TAVI. At baseline, the early heart-mediastinum ratio (H/M) was within normal limits (3.0±0.5), but the delayed H/M was low (2.6±0.6) and the washout rate (WR) was high (34±13%). WR negatively correlated with aortic valve area (r=-0.389, P<0.01) and cardiac output (r=-0.595, P<0.01) and positively correlated with norepinephrine (r=0.519, P<0.01) and log NT-proBNP level (r=0.613, P<0.01). After TAVI, there were significant decreases in the norepinephrine level (366±179 ng/mL vs. 276±125 ng/mL, P<0.01) and WR (34±13 vs. 26±11%, P<0.01). CONCLUSIONS: The WR of MIBG was a useful marker of CSN activity and severity of AS. Immediate improvement of CSN activity after TAVI implied that AS hemodynamics per se enhanced CSN.

Prevalence of chronic postsurgical pain after thoracotomy and total knee arthroplasty: a retrospective multicenter study in Japan (Japanese Study Group of Subacute Postoperative Pain).

We performed a multicenter observational study to assess the prevalence and risk factors of persistent pain after lung cancer surgery and total knee arthroplasty (TKA) in the Japanese population. After receiving Ethics Committee approval, a retrospective chart review was performed for patients who underwent surgery at seven university hospitals in Japan in 2013. A total of 511 patients who underwent lung cancer surgery and 298 patients who underwent TKA were included. The prevalence of chronic postsurgical pain (CPSP) at 3 and 6 months was 18 and 12% after lung surgery and 49 and 33% after TKA, respectively. The prevalence of analgesic use at 3 and 6 months was 16 and 9% after lung surgery and 34 and 22% after TKA, respectively. In both groups, preoperative analgesic use was associated with CPSP. Anesthetic methods or techniques during both types of surgery did not significantly affect the prevalence of CPSP. This is the first study in which the prevalence of CPSP after lung surgery and TKA in Japanese population was extensively evaluated in a multicenter trial. Further prospective studies are needed to confirm the prevalence of CPSP in the Japanese population and to identify risk factors and prevention methods.

Increased risk of paclitaxel-induced peripheral neuropathy in patients using clopidogrel: a retrospective pilot study.

Paclitaxel-induced peripheral neuropathy (PIPN) is one of the serious adverse events associated with paclitaxel-based cancer treatments. A recent case study showed that the antiplatelet agent clopidogrel inhibits paclitaxel metabolism via cytochrome P450 (CYP) 2C8, resulting in severe PIPN. The aim of this study was to determine the impact of clopidogrel as a risk factor for the development of PIPN, using a retrospective cohort study. Data from paclitaxel-treated patients with or without clopidogrel and low-dose aspirin treatment were retrieved from medical charts. A total of 161 adult patients were included in this study: 135 were controls, 9 were clopidogrel-treated and 17 were aspirin-treated. The clopidogrel group had a greater proportion of males and a higher rate of comorbidities, such as diabetes mellitus and dyslipidemia, than the control group. However, patient characteristics were similar between the clopidogrel and aspirin groups. Severe PIPN was diagnosed in 3 (2.2%) and 2 (22.2%) patients in the control and clopidogrel groups, respectively (odds ratio: 12.0; p = 0.031). No patients in the aspirin group presented with severe neuropathy. These pilot data suggest that concomitant treatment with clopidogrel leads to a greater risk of PIPN. The avoidance of concomitant clopidogrel use may be effective in reducing clopidogrel-associated PIPN.

Noradrenaline infusion prevents anesthesia-induced hypotension in severe aortic stenosis patients undergoing transcatheter aortic valve replacement: a retrospective observational study.

BACKGROUND: Patients with severe aortic valve stenosis (AS) are particularly prone to developing hypotension during general anesthesia induction, which increases postoperative morbidity and mortality. Although the preventive effect of a single vasopressor dose on anesthesia-induced hypotension has been reported, the effects of continuous vasopressor infusion are unknown. This study aimed to assess the effect of noradrenaline (NAd) infusion on hemodynamic stability during general anesthesia induction in severe AS patients undergoing transcatheter aortic valve replacement (TAVR). METHODS: This single-center, retrospective study included severe AS patients who underwent elective TAVR. Patients in the NAd group received a continuous prophylactic NAd infusion of 0.1 µg/kg/min from the time of anesthesia induction. The control group received inotropes and vasopressors as indicated by the occurrence of hypotension. The primary outcome was the lowest mean blood pressure (MBP) before the start of surgery. RESULTS: The study included 68 patients in the NAd group and 113 in the control group. The lowest MBP before the start of surgery was significantly higher in the NAd group than in the control group (63 ± 15 vs 47 ± 13 mmHg, P < 0.01). MBP immediately before intubation was also significantly higher in the NAd group (75 ± 17 vs 57 ± 16 mmHg, P < 0.01). Differences in postoperative complications between the groups were negligible. CONCLUSION: Continuous administration of NAd at 0.1 µg/kg/min in patients with severe AS might prevent hypotension during general anesthesia induction for TAVR.

Anesthesia management of laparoscopic right colectomy in an older patient with postoperative tetralogy of Fallot with residual anomaly.

BACKGROUND: Diversity in hemodynamics of adult congenital heart disease necessitates a case-by-case selection of appropriate surgical and anesthetic options. However, previous case reports regarding the management of laparoscopic surgery in adult patients with congenital heart disease are limited. CASE PRESENTATION: A 72-year-old man who underwent a laparoscopic right colectomy for colon cancer had a residual ventricular septal defect and right ventricular outflow tract obstruction despite post-repair of tetralogy of Fallot. Pulmonary hypertension or right ventricular dysfunction was not observed. The preoperative pulmonary to systemic blood flow ratio (Qp/Qs) was 2.3. After positive pressure ventilation and insufflation, the amount of left-to-right ventricular shunting decreased, and the Qp/Qs approached 1.0, as calculated from pulmonary arterial and systemic arterial blood gas analysis. CONCLUSIONS: Laparoscopic surgery might be tolerable in patients with tetralogy of Fallot who have preserved the right ventricular function, left-to-right ventricular shunting, and no high pulmonary vascular resistance.

Unraveling the directional relationship of sleep and migraine-like pain.

Migraine and sleep disorders are common co-morbidities. Patients frequently link their sleep to migraine attacks suggesting a potential causal relationship between these conditions. However, whether migraine pain promotes or disrupts sleep or whether sleep disruption can increase the risk of migraine remains unknown. We assessed the potential impact of periorbital allodynia, a measure consistent with migraine-like pain, from multiple preclinical models on sleep quantity and quality. Additionally, we evaluated the possible consequences of sleep deprivation in promoting susceptibility to migraine-like pain. Following the implantation of electroencephalogram/electromyography electrodes to record sleep, mice were treated with either single or repeated systemic injections of nitroglycerin at the onset of their active phase (i.e. nocturnal awake period). Neither single nor repeated nitroglycerin affected the total sleep time, non-rapid eye movement sleep, rapid eye movement sleep, sleep depth or other measures of sleep architecture. To account for the possible disruptive effects of the surgical implantation of electroencephalogram/electromyography electrodes, we used immobility recordings as a non-invasive method for assessing sleep-wake behaviour. Neither single nor repeated nitroglycerin administration during either the mouse sleep (i.e. daylight) or active (i.e. night) periods influenced immobility-defined sleep time. Administration of an inflammatory mediator mixture onto the dura mater at either sleep or active phases also did not affect immobility-defined sleep time. Additionally, inhalational umbellulone-induced migraine-like pain in restraint-stressed primed mice did not alter immobility-defined sleep time. The possible influence of sleep disruption on susceptibility to migraine-like pain was evaluated by depriving female mice of sleep over 6 h with novel objects, a method that does not increase circulating stress hormones. Migraine-like pain was not observed following acute sleep deprivation. However, in sleep-deprived mice, subthreshold doses of systemic nitroglycerin or dural calcitonin gene-related peptide induced periorbital cutaneous allodynia consistent with migraine-like pain. Our data reveal that while migraine-like pain does not significantly disrupt sleep, sleep disruption increases vulnerability to migraine-like pain suggesting that a therapeutic strategy focused on improving sleep may diminish migraine attacks.

Intraoperative Transesophageal Echocardiography Evaluation of Tricuspid Valve Re-repair for Ebstein's Anomaly.

Postoperative stenosis or regurgitation of the tricuspid valve is common and affects the prognosis after repair surgery of Ebstein's anomaly. However, it is unclear how intraoperative echocardiography influences the postoperative course. We report a longitudinal echocardiography course including intraoperative transesophageal echocardiography in a cone reconstruction procedure for Ebstein's anomaly in a 17-year-old woman. Tight tricuspid valvuloplasty was preferred, but the tricuspid annulus enlarged rather after surgery. The evaluation of the tricuspid valve form and function using intraoperative echocardiography could support the surgeon's impression.

Perioperative Management of Congenital Diaphragmatic Hernia Repair in a Patient With Univentricular Circulation: A Case Report.

The survival rate in congenital diaphragmatic hernia (CDH) with complex heart defects is low. Although the current consensus on the indications for surgical repair of CDH without heart defects has improved surgical outcomes, the surgical indication for CDH with complex heart defects remains unclear. Herein, we report the perioperative management of a patient with univentricular circulation who underwent CDH repair. Thus, patients with CDH complicated by univentricular anatomy may tolerate surgery depending on preserved respiratory function.

Intraoperative Heparin Resistance after Administration of Andexanet Alfa to Manage an Internal Iliac Artery Aneurysm Rupture: A Case Report.

Antithrombotic agents are increasingly prescribed to older adults; however, they are associated with bleeding-related complications. We describe a case of intraoperative heparin resistance after administration of andexanet alfa (AA). An 81-year-old man was diagnosed with a ruptured internal iliac artery aneurysm. The patient required emergency endovascular aneurysm repair and was treated with AA because he was receiving apixaban. Despite high-dose intraoperative heparin administration, his activated coagulation time was not prolonged. Our findings suggest that AA should be administered with caution in patients experiencing potentially fatal bleeding (requiring surgical intervention) who are also receiving direct oral anticoagulants.

Resting phase-administration of lemborexant ameliorates sleep and glucose tolerance in type 2 diabetic mice.

Sleep disorders are associated with increased risk of obesity and type 2 diabetes. Lemborexant, a dual orexin receptor antagonist (DORA), is clinically used to treat insomnia. However, the influence of lemborexant on sleep and glucose metabolism in type 2 diabetic state has remained unknown. In the present study, we investigated the effect of lemborexant in type 2 diabetic db/db mice exhibiting both sleep disruption and glucose intolerance. Single administration of lemborexant at the beginning of the light phase (i.e., resting phase) acutely increased total time spent in non-rapid eye movement (NREM) and REM sleep in db/db mice. Durations of NREM sleep-, REM sleep-, and wake-episodes were also increased by this administration. Daily resting-phase administration of lemborexant for 3-6 weeks improved glucose tolerance without changing body weight and glucose-stimulated insulin secretion in db/db mice. Similar improvement of glucose tolerance was caused by daily resting-phase administration of lemborexant in obese C57BL/6J mice fed high fat diet, whereas no such effect was observed in non-diabetic db/m+ mice. Diabetic db/db mice treated daily with lemborexant exhibited increased locomotor activity in the dark phase (i.e., awake phase), although they did not show any behavioral abnormality in the Y-maze, elevated plus maze, and forced swim tests. These results suggest that timely promotion of sleep by lemborexant improved the quality of wakefulness in association with increased physical activity during the awake phase, and these changes may underlie the amelioration of glucose metabolism under type 2 diabetic conditions.

Warfarin Reversal With Four-Factor Prothrombin Complex Concentrate for Left Ventricular Assist Device Conversion Surgery Monitored by TEG6s: A Case Report.

Left ventricular assist devices (LVADs) require careful therapeutic anticoagulation with warfarin to prevent pump thrombosis. However, the best method to reverse warfarin for elective LVAD conversion surgery with massive bleeding remains unclear. We report the case of a 39-year-old Japanese man who was administered a four-factor prothrombin complex concentrate (4F-PCC) as warfarin reversal when he underwent conversion surgery from paracorporeal LVAD to implantable LVAD. 4F-PCC with co-administration of vitamin K reduced the international normalized ratio and R time in TEG6s (Haemonetics Corporation, USA) immediately. The effect was prolonged, and good hemostasis was achieved. 4F-PCC with vitamin K provided good hemostasis in our patient; therefore, 4F-PCC could be a useful tool for elective LVAD conversion surgery with expected massive bleeding and requiring immediate warfarin reversal.

Suvorexant and mirtazapine improve chronic pain-related changes in parameters of sleep and voluntary physical performance in mice with sciatic nerve ligation.

Both chronic pain and sleep disorders are associated with a reduction in the quality of life. They can be both a cause and a consequence of each other, and should therefore be simultaneously treated. However, optimal treatments for chronic pain-related sleep disorders are not well established. Here, we aimed to investigate the effects of suvorexant, a novel sleep drug, and mirtazapine, a noradrenergic and specific serotonergic antidepressant, on pain-related changes in sleep parameters in a preclinical chronic pain mice model, by partial sciatic nerve ligation. We evaluated the quantity, duration, and depth of sleep by analyzing the electroencephalogram and voluntary activity by counting the number of wheel rotations to determine various symptoms of sleep disorders, including reduced total sleep time, fragmentation, low quality, and impaired activity in the daytime. Suvorexant and mirtazapine normalized the reduction in sleep time and fragmented sleep, further regaining the sleep depth at sleep onset in the chronic pain state in nerve-ligated mice. Mirtazapine also increased the percentage of rapid eye movement sleep in mice. Suvorexant decreased voluntary activity, which was prolonged after administration; however, mirtazapine did not decrease it. Although the effects of suvorexant and mirtazapine on sleep and activity are different, both suvorexant and mirtazapine could be potential therapeutic agents for chronic pain-related sleep disorders.

Anesthetic Management Using Remimazolam for Transcatheter Edge-to-Edge Repair of the Mitral Valve in Patients With Reduced Ejection Fraction: A Case Report of Two Cases.

Remimazolam is an ultrashort-acting benzodiazepine that causes minimal hemodynamic changes. We present two patients, with reduced ejection fraction, who underwent remimazolam anesthesia for transcatheter edge-to-edge repair of the mitral valve with the MitraClip system. In case 1, the patient's vitals were stable throughout the surgery. However, in case 2, which had a lower cardiac output, the patient's blood pressure decreased remarkably after anesthesia induction. Though remimazolam does not alter the cardiac output, it reportedly has vasodilatory effects. Since remimazolam can reduce blood pressure in patients where the reduction in cardiac output is compensated for by high peripheral vascular resistance, caution should be exercised.

[Examination of acute kidney injury after abdominal aortic aneurysm surgery].

BACKGROUND: Either suprarenal or infrarenal aortic clamping markedly reduces renal blood flow. This aortic clamping may cause postoperative acute kidney injury(AKI). METHODS: Fifty-four patients undergoing open abdominal aortic aneurysm (AAA) surgery were included in a retrospective study. Postoperative AKI defined as an absolute increase in serum creatinine (Cre) of more than or equal to 0.3 mg x dl(-1) or an increase in Cre of more than or equal to 50% within 48 hours after the end of the procedure. RESULTS: Thirteen patients developed AKI, but none of them required dialysis. The patients with AKI had higher preoperative Cre, longer operation, longer clamp time and more use of diuretics intra- and postoperatively. CONCLUSIONS: AKI occurred in 24.1% of patients undergoing AAA surgery. Risk factors for AKI were preoperative Cre, operation time, clamp time and use of diuretics.

Percutaneous transseptal transcatheter mitral valve-in-valve replacement for degenerated mitral bioprosthesis: The first experience in Japan.

A 76-year-old woman had received surgical mitral valve replacement with Magna Mitral Ease (Edwards Lifesciences, Irvine, CA, USA) 25 mm for functional severe mitral regurgitation 6 years previously. She presented recurrence of heart failure due to severe stenotic and moderate regurgitant degeneration of the implanted mitral bioprosthesis. Considering her comorbidities and left ventricular systolic dysfunction, our heart valve team eventually decided to perform percutaneous transseptal transcatheter mitral valve-in-valve replacement instead of surgical redo mitral valve replacement, using a 26 mm SAPIEN 3 valve (Edwards Lifesciences) via trans-femoral approach. Post-procedural course was uneventful and she was discharged on post-procedural day 2. This is, to the best of our knowledge, the first case of successful percutaneous transseptal transcatheter mitral valve-in-valve replacement in Japan. Further large-scale prospective studies are warranted to validate its long-term safety and efficacy, particularly by comparing with the redo surgery. .

[The influence of remifentanil on intra- and postoperative drug cost].

BACKGROUND: Intraoperative use of remifentanil requires much more analgesics postoperatively. Moreover, remifentanil causes intraoperative hypotension and bradycardia. METHODS: The objectives are to compare intra- and post-operative drug cost between patients who received remifentanil (Group R, n = 72) and those who received fentanyl (Group F, n = 66) during laparoscopic cholecystectomy retrospectively. RESULTS: The baseline demographics were similar between the two groups. Intraoperative drug costs were 7,782 +/- 1,579 yen in Group R and 6,235 +/- 1,037 yen in Group E Postoperative drug costs were 364 +/- 521 yen in Group R and 146 +/- 153 yen in Group E Total drug costs were 8,167 +/- 1,607 yen in Group R and 6,381 +/- 1,042 yen in Group E These reached statistical significance (P < 0.01). Length of hospital stay (days) between the two groups were comparable. CONCLUSIONS: Remifentanil anesthesia requires much more intra- and post-operative drug cost than fentanyl anesthesia for laparoscopic cholecystectomy.