Ah-Reum Cho

Maintenance anaesthetics during remifentanil-based anaesthesia might affect postoperative pain control after breast cancer surgery

BACKGROUND Although remifentanil provides profound analgesia during operation, postoperative occurrence of hyperalgesia and tolerance after remifentanil administration could be a challenge to the postoperative pain control. In this investigation, we sought to determine the effect of maintenance with propofol or sevoflurane on postoperative analgesia after remifentanil-based anaesthesia. METHODS Two hundred and fourteen women undergoing breast cancer surgery under remifentanil-based general anaesthesia were randomly included in this prospective and double-blind trial. The patients were anaesthetized with sevoflurane (S) or propofol (P) under high (H) or low (L) effect-site concentration (Ce) of remifentanil-based anaesthesia using a target-controlled infusion system; the patients were allocated into the SH, SL, PH, and PL groups. Pain intensity (visual analogue score, VAS) and cumulative morphine requirements were recorded 30 min, 1, 6, 12, and 24 h after operation. RESULTS The patient characteristics were similar. Cumulative morphine consumption at 24 h after surgery was higher in the SH group [38.6 (sd 14.9)] compared with the SL [31.5 (3.7)], PH [31.7 (8.3)], and PL groups [30.1 (6.1)] (P<0.001). The VAS scores during 24 h after surgery were also higher in the SH group than the SL, PH, and PL groups (P<0.001). CONCLUSIONS Remifentanil hyperalgesia was induced by high dose of remifentanil-based anaesthesia during sevoflurane anaesthesia, whereas that was not apparent during propofol anaesthesia. Also, remifentanil hyperalgesia did not occur during low dose of remifentanil-based anaesthesia. Maintenance of propofol during high-dose remifentanil-based anaesthesia provided better postoperative analgesia.

The effects of anesthetics on chronic pain after breast cancer surgery.

BACKGROUND:The incidence and predictive factors for chronic pain after breast cancer surgery have been widely studied. Because it negatively affects patients’ daily lives, methods to prevent and reduce chronic pain and its severity should be developed. Our previous study showed that propofol anesthesia has an antihyperalgesic effect under remifentanil-induced hyperalgesia and reduced acute pain compared with sevoflurane anesthesia. In this study, we investigated the hypothesis that propofol would prevent the development and severity of chronic pain after breast cancer surgery, as in acute pain. METHODS:A retrospective study was conducted with 175 women (n = 86 in the propofol group and n = 89 in the sevoflurane group) aged 20 to 65 years who underwent breast cancer surgery between March 2007 and December 2008. Patients were followed up by telephone in July 2011. Analysis included incidence, severity, and duration of chronic pain between propofol and sevoflurane groups. Severity was categorized into mild, moderate, and severe pain. Duration of chronic pain was also divided into 3 categories by 1-year time interval. Risk factors associated with the incidence and severity of chronic pain after breast cancer surgery were also identified. RESULTS:Chronic pain after breast cancer surgery was more likely to occur in the sevoflurane group compared with the propofol group (95% confidence interval [CI] 1.146–1.809, P = 0.007). Among patients with chronic pain, neither the severity (95% CI 0.516–7.419) nor duration (95% CI 0.106–1.007) differed between patients receiving sevoflurane and propofol. Younger age (95% CI 0.907–0.992, P = 0.021), axillary lymph node dissection (95% CI 1.204–1.898, P = 0.003), 24-hour postoperative morphine consumption (95% CI 1.004–1.116, P = 0.036), and sevoflurane (95% CI 1.146–1.809, P = 0.007) were predictive factors for the development of chronic pain. Higher 24-hour postoperative morphine consumption (95% CI 1.001–1.379, P = 0.049) increased the severity of chronic pain. CONCLUSIONS:This study showed that propofol anesthesia was associated with a lower incidence of chronic pain after breast cancer surgery than sevoflurane anesthesia. However, propofol did not have a significant effect on severity and duration of chronic pain. Further prospective studies are needed to confirm the validity of these provocative findings.

The effects of sevoflurane and propofol anesthesia on cerebral oxygenation in gynecological laparoscopic surgery

Background Both the Trendelenburg position and pneumoperitoneum with carbon dioxide have been reported to increase intracranial pressure (ICP) and to alter cerebral blood flow or cerebral blood volume. Also anesthetic agents have variable effects on cerebral hemodynamics and ICP. The present study was conducted to determine whether regional cerebral oxygen saturation (rSO2) values differ between propofol and sevoflurane anesthesia during laparoscopic surgery in the Trendelenburg position. Methods Thirty-two adult women undergoing gynecological laparoscopic surgery were divided into sevoflurane and propofol groups. rSO2 values were recorded at 10 min after induction in the neutral position (Tpre), 10 min after the pneumoperitoneum in the Trendelenburg position (Tpt) and 10 min after desufflation in the neutral position (Tpost). For analysis of rSO2, we did ANOVA and univariate two-way ANCOVA with covariates being mean arterial pressure and end tidal carbon dioxide tension. Results Between sevoflurane and propofol groups, the change in rSO2 was significantly different even after ANCOVA. rSO2 at Tpt (76.3 ± 5.9% in sevoflurane vs 69.4 ± 5.8% in propofol) and Tpost (69.5 ± 7.1% in sevoflurane vs 63.8 ± 6.6% in propofol) were significantly higher in the sevoflurane group compared with the propofol group. In the propofol group, rSO2 at Tpost was significantly lower than at Tpre (71.1 ± 4.8%) and cerebral oxygen desaturation occurred in two patients (14.3%). Conclusions Significantly lower rSO2 values were observed in the propofol group during gynecological laparoscopic surgery. The possibility of cerebral oxygen desaturation should not be overlooked during propofol anesthesia even after desufflation of the abdomen in the neutral position.

Acute onset Lance-Adams syndrome following brief exposure to severe hypoxia without cardiac arrest -a case report-

Myoclonic status epilepticus (MSE) within the first 24 hours after cardiopulmonary resuscitation (CPR) predicts poor prognosis, enough to discontinue the treatment. In contrast, chronic MSE appearing a few days after CPR is called Lance-Adams syndrome (LAS), which is characterized by preserved intellect and a favorable prognosis. We herein report a case of LAS, which developed after a transient hypoxic event without an overt cardiac arrest due to hematoma formation in the neck after partial glossectomy. Differential diagnosis was also challenging as LAS was developed 8 hours after the hypoxic event.

Nasogastric tube insertion using airway tube exchanger in anesthetized and intubated patients

Background A nasogastric tube (NGT) is commonly inserted into patients undergoing abdominal surgery to decompress the stomach during or after surgery. However, for anatomic reasons, the insertion of NGTs into anesthetized and intubated patients may be challenging. We hypothesized that the use of a tube exchanger for NGT insertion could increase the success rate and reduce complications. Methods One hundred adult patients, aged 20–70 years, who were scheduled for gastrointestinal surgeries with general anesthesia and NGT insertion were enrolled in our study. The patients were randomly allocated to the tube-exchanger group or the control group. The number of attempts, the time required for successful NGT insertion, and the complications were noted for each patient. Results In the tube-exchanger group, the success rate of NGT insertion on the first attempt was 92%, which is significantly higher than 68%, the rate in the control group (P = 0.007). The time required for successful NGT insertion in the tube-exchanger group was 18.5 ± 8.2 seconds, which is significantly shorter than the control group, 75.1 ± 9.8 seconds (P < 0.001). Complications such as laryngeal bleeding and the kinking and knotting of the NGT occurred less often in the tube-exchanger group. Conclusions There were many advantages in using a tube-exchanger as a guide to inserting NGTs in anesthetized and intubated patients. Compared to the conventional technique, the use of a tube-exchanger resulted in a higher the success rate of insertion on the first attempt, a shorter procedure time, and fewer complications.

Accidental intrathecal injection of dopamine hydrochloride resulting in analgesic effects

Medication errors are defined as any error in the delivery process, whether there are any adverse consequences or not [1]. In the present case report, we describe an accidental intrathecal injection of dopamine hydrochloride (DA) which has not been previously reported in human. We were blinded to the fact due to the analgesic and anesthetic effects that seemed to have been achieved after the injection of DA. A 76 year-old man was scheduled for closed reduction and internal fixation of an intertrochanteric fracture of the right femur. His medical history included diabetes mellitus, hypertension and chronic renal failure with maintenance hemodialysis for the last 4 years. The blood glucose level was with 95-337 mg/dl and the blood pressure (BP) with 140-200/80-100 mmHg poorly controlled. The preoperative pulmonary function test revealed a severe restrictive respiratory disorder. We decided to apply a spinal anesthesia for his operation. Electrocardiogram, BP, heart rate (HR) and arterial hemoglobin oxygen saturation were measured after the patient was brought to the operating room. The BP was 160/80 mmHg and the HR showed 95 beats/min. A spinal anesthesia was performed at the L3-4 interspace with the patient in a left lateral position using a 25-gauge Quinke tip needle. The drug ampule assumed to content of 0.5% bupivacaine hydrochloride (20 mg/4 ml, Hana Pharm, Seoul, Korea) was passed by the nurse and 2.0 ml of drug was injected into the intrathecal space. Five minutes later, he was not able to sense cold sensation (alcohol swab) and pain (blunt needle) below T10 level and the surgery began. After skin incision, the patient seemed comfortable and the vital signs remained constant except a slight increase in BP with around 170/90 mmHg. In 30 minutes after incision, he complained of mild pain at the incision site. Shortly after, the nurse noticed that 80 mg of DA (200 mg/5 ml, Hana Pharm, Seoul, Korea) had been drawn and intrathecally injected instead of 0.5% bupivacaine (Fig. 1). 80 mg propofol was intravenously administered and a laryngeal mask airway (LMA) was inserted. Anesthesia was maintained using 0.5-1.0 MAC sevoflurane. We performed an arterial cannulation at the left radial artery and continuously monitored the arterial pressure. After induction of the general anesthesia, the BP decreased to 90/60 mmHg and the HR were decreased to 90 beats/min but the intraoperative course was uneventful. The surgery lasted for 1 hour and the LMA was removed thereafter. The patient was transferred to the intensive care unit (ICU) for observation. The patient was alert and BP and HR were 160-190/70-80 mmHg and 90-110 beats/min respectively. He complained of mild pain (VAS 3) soon after arrival at the ICU. Thirty minutes later, he complained of severe pain (VAS 7) which required additional analgesia. His pain was subsided after intravenous injection of 100 ug fentanyl. The motor and sensory functions that were examined by a neurologist at the ICU showed unremarkable findings. Twenty four hours later, the patient was transferred to the general ward. After two weeks of observation, he was discharged without any adverse events. In spite of our recommendation, he did not revisit the hospital within 1 month after discharge. We called him instead at 1 and 6 months after discharge. He was able to walk again and there were no remarkable complications. Fig. 1 Ampules of bupivacaine (left) and dopamine hydrochloride (right). They are similar in size, color, and shape. The present case illustrates a medication error whereby a wrong medication was administered to the intrathecal space. DA is easily available in the operating room as intravenous medication acting on the adrenergic and dopaminergic receptors, producing effects such as increased BP and HR. The intrathecal injection of DA has never been previously reported in humans. However, intrathecal dopaminergic agents have been used in studies of antinociceptive properties of spinal dopamine receptors in animals [2,3,4]. Increasing evidence suggests that the central dopamine system is involved in the modulation of nociception at the supraspinal and the spinal cord levels. Focal electrical stimulation in the origin of the A11 area suppresses the nociceptive responses of neurons in the spinal dorsal horn [2]. Yang et al. [3] demonstrated that intrathecal administered DA (up to 16.5 nM) produced significant and dose-dependent prolongation of the tail-flick latency. Recently, a higher dose of DA (100 uM) was injected in the spinal cord of rats demonstrating dopaminergic antinociceptive actions [4]. Besides dopaminergic receptors, it has been well known that α2-adrenergic receptors in the spinal cord produce a dose-dependent antinociceptive effect [5]. When a large dose of DA is administered intravenously, α-adrenergic activation is dominant. However, it is not known whether this dose-dependent receptor affinity of intravenous DA can be applied equally to intrathecally administered DA. It is difficult to suggest the clinical use of DA as an intrathecal analgesic from this case report, because there are no evidences to prove any advantages of DA compared to local anesthetics or α2 agonists. Moreover, although there was no clinical neurologic complication in this case, DA can induce vasoconstriction in the spinal cord, which might result in ischemia and irreversible spinal cord injury. However, numerous studies have demonstrated that spinal dopaminergic and adrenergic receptors have shown to play critical roles in pain modulation. Since DA stimulates both receptors and our case report showed an analgesic effect of intrathecal DA, it intrigues us to find a contributing role of intrathecal DA in the analgesic management.

Hemorrhagic shock occurring due to a concealed hematoma after insertion of a subclavian venous catheter in a patient undergoing anticoagulation therapy -a case report-

A 74-year-old man who had been receiving warfarin for atrial fibrillation, underwent emergency thrombectomy. A central venous catheter (CVC) was inserted via the left subclavian vein, and heparin was administered to prevent preoperative and postoperative thrombotic events. After an uneventful thrombectomy, the patient was transferred to the intensive care unit (ICU). On the second postoperative day, the patient developed syncope and his blood pressure and oxygen saturation decreased. A computed tomography (CT) revealed a huge hematoma under the pectoralis major muscle. The patient was then treated with continuous renal replacement therapy and mechanical ventilation for multiorgan dysfunction syndrome, which developed due to hemorrhagic shock in the ICU. These findings suggest that when a CVC is inserted in patients requiring anticoagulant therapy, the possible risk of excessive bleeding must be carefully considered. Further, choosing a proper insertion site and performing an ultrasound-guided aspiration may be helpful in preventing these complications.

Ultrasound-guided superficial cervical plexus block under dexmedetomidine sedation versus general anesthesia for carotid endarterectomy: a retrospective pilot study

Background Carotid endarterectomy (CEA) has been performed under regional and general anesthesia (GA). The general anesthesia versus local anesthesia for carotid surgery study compared the two techniques and concluded that there was no difference in perioperative outcomes. However, since this trial, new sedative agents have been introduced and devices that improve the delivery of regional anesthesia (RA) have been developed. The primary purpose of this pilot study was to compare intraoperative hemodynamic stability and postoperative outcomes between GA and ultrasound-guided superficial cervical plexus block (UGSCPB) under dexmedetomidine sedation for CEA. Methods Medical records from 43 adult patients who underwent CEA were retrospectively reviewed, including 16 in the GA group and 27 in the RA group. GA was induced with propofol and maintained with sevoflurane. The UGSCPB was performed with ropivacaine under dexmedetomidine sedation. We compared the intraoperative requirement for vasoactive drugs, postoperative complications, pain scores using the numerical rating scale, and the duration of hospital stay. Results There was no difference between groups in the use of intraoperative antihypertensive drugs. However, intraoperative inotropic and vasopressor agents were more frequently required in the GA group (p<0.0001). In the GA group, pain scores were significantly higher during the first 24 h after surgery (p<0.0001 between 0-6 h, p<0.004 between 6-12 h, and p<0.001 between 12-24 h). The duration of hospital stay was significantly more in the GA group (13.3±4.6 days in the GA group vs. 8.5±2.4 days in the RA group, p<0.001). Conclusion In this pilot study, intraoperative hemodynamic stability and postoperative outcomes were better in the RA compared to the GA group.

Effect of remifentanil on pre-osteoclast cell differentiation in vitro

Background The structure and function of bone tissue is maintained through a constant remodeling process, which is maintained by the balance between osteoblasts and osteoclasts. The failure of bone remodeling can lead to pathological conditions of bone structure and function. Remifentanil is currently used as a narcotic analgesic agent in general anesthesia and sedation. However, the effect of remifentanil on osteoclasts has not been studied. Therefore, we investigated the effect of remifentanil on pre-osteoclast (pre-OCs) differentiation and the mechanism of osteoclast differentiation in the absence of specific stimulus. Methods Pre-OCs were obtained by culturing bone marrow-derived macrophages (BMMs) in osteoclastogenic medium for 2 days and then treated with various concentration of remifentanil. The mRNA expression of NFATc1 and c-fos was examined by using real-time PCR. We also examined the effect of remifentanil on the osteoclast-specific genes TRAP, cathepsin K, calcitonin receptor, and DC-STAMP. Finally, we examined the influence of remifentanil on the migration of pre-OCs by using the Boyden chamber assay. Results Remifentanil increased pre-OC differentiation and osteoclast size, but did not affect the mRNA expression of NFATc1 and c-fos or significantly affect the expression of TRAP, cathepsin K, calcitonin receptor, and DC-STAMP. However, remifentanil increased the migration of pre-OCs. Conclusions This study suggested that remifentanil promotes the differentiation of pre-OCs and induces maturation, such as increasing osteoclast size. In addition, the increase in osteoclast size was mediated by the enhancement of pre-OC migration and cell fusion.