Youngkwon Ko

Anesthesia and sedation outside of the operating room.

Due to rapid evolution and technological advancements, medical personnel now require special training outside of their safe zones. Anesthesiologists face challenges in practicing in locations beyond the operating room. New locations, inadequate monitoring devices, poor assisting staff, unfamiliarity of procedures, insufficient knowledge of basic standards, and lack of experience compromise the quality of patient care. Therefore, anesthesiologists must recognize possible risk factors during anesthesia in nonoperating rooms and familiarize themselves with standards to improve safe practice. This review article emphasizes the need for standardizing hospitals and facilities requiring nonoperating room anesthesia, and encourages anesthesiologists to take the lead in applying these practice guidelines to improve patient outcomes and reduce adverse events.

Sevoflurane exposure during the neonatal period induces long‐term memory impairment but not autism‐like behaviors

To examine whether neonatal exposure to sevoflurane induces autism‐like behaviors in mice.

Expression of LC3 and Beclin 1 in the spinal dorsal horn following spinal nerve ligation-induced neuropathic pain.

Impaired spinal GABAergic inhibitory function is known to be pivotal in neuropathic pain (NPP). At present, data concerning time-dependent alterations in cell type and cell death in the spinal dorsal horn are highly controversial, likely related to the experimental NPP model used. In this study, we examined the expression of autophagy using a L5 spinal nerve ligation (SNL)-induced neuropathic pain rat model. Following ligation of the spinal nerve, neuropathic pain behavior, such as mechanical allodynia, was induced rapidly and maintained for 14 days. After testing for mechanical allodynia, we assessed the changes in expression of LC3 and Beclin 1 in the spinal cord following SNL. Immunohistochemical analysis showed that the levels of LC3 and Beclin 1 protein in the ipsilateral L5 spinal dorsal horn were significantly elevated on day 14 following SNL. Double immunohistochemical analysis further confirmed increases in LC3 and Beclin 1 in mostly neurons and a few astrocytes following SNL. LC3 and Beclin 1 expressions were upregulated in GABAergic interneurons of spinal dorsal horn after SNL, while the loss of GABAergic interneurons did not change significantly. Our results suggest that autophagic disruption in GABAergic interneurons and astrocytes following peripheral nerve injury might be involved in the induction and maintenance of neuropathic pain.

Efficacy of the oral neurokinin-1 receptor antagonist aprepitant administered with ondansetron for the prevention of postoperative nausea and vomiting.

Background 5-HT3 receptor antagonist, dexamethasone and droperidol were used for the prevention of postoperative nausea and vomiting (PONV). Recently, neurokinin-1 (NK1) antagonist has been used for PONV. We evaluated the effect of oral aprepitant premedication in addition to ondansetron. Methods A total 90 patients scheduled for elective rhinolaryngological surgery were allocated to three groups (Control, Ap80, Ap125), each of 30 at random. Ondansetron 4 mg was injected intravenously to all patients just before the end of surgery. On the morning of surgery, 80 mg and 125 mg aprepitant were additionally administered into the Ap80 group and Ap125 group, respectively. The rhodes index of nausea, vomiting and retching (RINVR) was checked at 6 hr and 24 hr after surgery. Results Twelve patients who used steroids unexpectedly were excluded. Finally 78 patients (control : Ap80 : Ap125 = 24 : 28 : 26) were enrolled. Overall PONV occurrence rate of Ap125 group (1/26, 3.9%) was lower (P = 0.015) than the control group (7/24, 29.2%) at 6 hr after surgery. The nausea distress score of Ap125 group (0.04 ± 0.20) was lower (P = 0.032) than the control group (0.67 ± 1.24) at 6 hr after surgery. No evident side effect of aprepitant was observed. Conclusions Oral aprepitant 125 mg can be used as combination therapy for the prevention of PONV.

Genome-wide expression profiling of complex regional pain syndrome.

Complex regional pain syndrome (CRPS) is a chronic, progressive, and devastating pain syndrome characterized by spontaneous pain, hyperalgesia, allodynia, altered skin temperature, and motor dysfunction. Although previous gene expression profiling studies have been conducted in animal pain models, there genome-wide expression profiling in the whole blood of CRPS patients has not been reported yet. Here, we successfully identified certain pain-related genes through genome-wide expression profiling in the blood from CRPS patients. We found that 80 genes were differentially expressed between 4 CRPS patients (2 CRPS I and 2 CRPS II) and 5 controls (cut-off value: 1.5-fold change and p<0.05). Most of those genes were associated with signal transduction, developmental processes, cell structure and motility, and immunity and defense. The expression levels of major histocompatibility complex class I A subtype (HLA-A29.1), matrix metalloproteinase 9 (MMP9), alanine aminopeptidase N (ANPEP), l-histidine decarboxylase (HDC), granulocyte colony-stimulating factor 3 receptor (G-CSF3R), and signal transducer and activator of transcription 3 (STAT3) genes selected from the microarray were confirmed in 24 CRPS patients and 18 controls by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). We focused on the MMP9 gene that, by qRT-PCR, showed a statistically significant difference in expression in CRPS patients compared to controls with the highest relative fold change (4.0±1.23 times and p = 1.4×10−4). The up-regulation of MMP9 gene in the blood may be related to the pain progression in CRPS patients. Our findings, which offer a valuable contribution to the understanding of the differential gene expression in CRPS may help in the understanding of the pathophysiology of CRPS pain progression.

Effect of lidocaine (40 mg) mixed to prevent injection pain of propofol on the intubating conditions and onset time of rocuronium

Background To analyze how lidocaine 40 mg mixed prevents injection pain of propofol affects the onset time of rocuronium, tracheal intubating conditions and intubation related hemodynamic changes. Methods This study consisted of 70 patients with an American Society of Anesthesiologists (ASA) physical status class 1 or 2 for general anesthesia. All the patients were randomly allocated into two groups: propofol 2 mg/kg plus normal saline 2 ml (Group C) and propofol 2 mg/kg plus 2% lidocaine 40 mg (Group L). Each group was administrated intravenously during induction and the patient was intubated 1 minute after an injection of 0.6 mg/kg of rocuronium. The time at disappearance of the first twitch and intubation scores were recorded. Also, blood pressure and heart rate were measured at the baseline, after intravenous injection of propofol, before intubation, and at 0, 1, 2, 3 and 5 minutes after intubation. Results There were no significant differences between group C and L (P > 0.05). Conclusions 40 mg of lidocaine mixed with propofol to prevent injection pain did not affect the onset time of rocuronium, intubating conditions and intubation related hemodynamic changes.

Vomiting after a pediatric adenotonsillectomy: comparison between propofol induced sevoflurane-nitrous oxide maintained anesthesia and TIVA with propofol-remifentanil

Background Anesthesia methods and drugs affect postoperative nausea and vomiting. Propofol is known to have antiemetic effects. We compared the incidence of postoperative vomiting (POV) in children undergoing an adenotonsillectomy; anesthesia in one group was induced with propofol and maintained with sevoflurane and nitrous oxide, and the other group received total intravenous anesthesia (TIVA) with propofol-remifentanil. Methods Ninety children, ASA physical status I, were assigned randomly to one of two groups. In the PSN group, anesthesia was maintained with 2-3 vol% sevoflurane and 50% nitrous oxide. In the PR group, anesthesia was maintained with 10 mg/kg/h propofol and 0.25 µg/kg/min remifentanil. In both groups, anesthesia was induced with 0.5 µg/kg remifentanil and 2 mg/kg propofol. The incidence of POV and the need for rescue antiemetics were assessed in the postanesthesia care unit at 6, 12, and 24 hours postoperatively. Results The total incidence of POV was not significantly different between the groups; POV occurred in eight (17.7%) and three (6.7%) children in the PSN and PR groups, respectively. Postoperative frequency of retching in the recovery room was significantly higher in the PSN group, with four children (8.9%) in the PSN group compared to none (0%) in the PR group (P = 0.041). The frequency of POV 24 hrs after exiting the recovery room tended to be higher in the PSN group than the PR group, but no statistically significant difference was observed. Conclusions If the development of POV in the early anesthetic recovery phase of children undergoing adenotonsillectomy is adequately prevented, propofol-induced anesthesia maintained with sevoflurane-nitrous oxide is as safe as TIVA with propofol-remifentanil.

Single and multiple sevoflurane exposures during pregnancy and offspring behavior in mice

The second trimester is a period of neurogenesis and neuronal migration, which can be affected by exposure to anesthetics. Studies also suggest that multiple exposures may have a greater impact on neurodevelopment.

Sevoflurane Exposure during the Critical Period Affects Synaptic Transmission and Mitochondrial Respiration but Not Long-term Behavior in Mice

Background: Anesthesia during the synaptogenic period induces dendritic spine formation, which may affect neurodevelopment. The authors, therefore, evaluated whether changes in synaptic transmission after dendritic spine formation induced by sevoflurane were associated with long-term behavioral changes. The effects of sevoflurane on mitochondrial function were also assessed to further understand the mechanism behind spinogenesis. Methods: Postnatal day 16 to 17 mice were exposed to sevoflurane (2.5% for 2 h), and synaptic transmission was measured in the medial prefrontal cortex 6 h or 5 days later. The expression of postsynaptic proteins and mitochondrial function were measured after anesthesia. Long-term behavioral changes were assessed in adult mice. Results: Sevoflurane increased the expression of excitatory postsynaptic proteins in male and female mice (n = 3 to 5 per group). Sevoflurane exposure in male mice transiently increased miniature excitatory postsynaptic current frequency (control: 8.53 ± 2.87; sevoflurane: 11.09 ± 2.58) but decreased miniature inhibitory postsynaptic current frequency (control: 10.18 ± 4.66; sevoflurane: 6.88 ± 2.15). Unexpectedly, sevoflurane increased miniature inhibitory postsynaptic current frequency (control: 1.81 ± 1.11; sevoflurane: 3.56 ± 1.74) in female mice (neurons, n = 10 to 21 per group). Sevoflurane also increased mitochondrial respiration in male mice (n = 5 to 8 per group). However, such changes from anesthesia during the critical period did not induce long-term behavioral consequences. Values are presented as mean ± SD. Conclusions: Sevoflurane exposure during the critical period induces mitochondrial hyperactivity and transient imbalance of excitatory/inhibitory synaptic transmission, without long-lasting behavioral consequences. Further studies are needed to confirm sexual differences and to define the role of mitochondrial activity during anesthesia-induced spine formation.

Expression of granulocyte colony-stimulating factor 3 receptor in the spinal dorsal horn following spinal nerve ligation-induced neuropathic pain

In previous studies that have profiled gene expression in patients with complex regional pain syndrome (CRPS), the expression of granulocyte colony-stimulating factor 3 receptor (G-CSFR) was elevated, as were a number of pain-associated genes. The present study determined the expression of G-CSFR and the mechanisms by which it may affect hypersensitivity, focusing on the signal transducer and activator of transcription 3 (STAT3)/transient receptor potential cation channel subfamily V 1 (TRPV1) signaling pathway in particular, which is an important mediator of pain. Following L5 spinal nerve ligation (SNL) surgery, the protein and mRNA levels of G-CSFR increased in the ipsilateral spinal dorsal horn when compared with the sham and/or contralateral control. Double immunofluorescence further demonstrated that G-CSFR colocalized with TRPV1 and phosphorylated STAT in the neurons of the spinal dorsal horn. G-CSF treatment led to an increase in G-CSFR and TRPV1 expression and phosphorylation of STAT3. These results indicate that G-CSF-induced G-CSFR expression may activate TRPV1 by promoting phosphorylation of STAT3. Collectively, the results suggest, for the first time, that the expression of G-CSFR in neurons following peripheral nerve injury may be involved in the induction and maintenance of neuropathic pain through the STAT3 and TRPV1 signaling pathway.