Woo Jae Jeon

Comparison of the Proseal LMA and intersurgical I-gel during gynecological laparoscopy

Background The relatively recently developed I-gel (Intersurgical Ltd., Workingham, England) is a supraglottic airway device designed for single-use that, unlike conventional LMAs, does not require an inflatable cuff. In addition, the I-gel, much like the Proseal LMA (PLMA), has a gastric drainage tube associated with an upper tube for decompression of the stomach, thereby avoiding acid reflux and decreasing the risk of pulmonary absorption. The purpose of this study was to compare PLMA and I-gel devices in patients undergoing gynecological laparoscopy based on sealing pressure before and during pneumoperitoneum, insertion time, and gas exchange. Methods Following Institutional Review Board approval and written informed consent, 30 adult patients were randomly allocated to one of two groups (the PLMA or I-gel group). In each case, insertion time and number of attempts were recorded. After successful insertion, airway leak pressure was measured. Results Successful insertion and mechanical ventilation with both supraglottic airway devices was achieved on the first attempt in all 30 patients, and there were no significant differences with respect to insertion time. Likewise, leak pressure did not vary significantly either between or within groups after CO2 insufflation. In addition, differences between leak volume and leak fraction between groups were not significant. Conclusions The results of our study indicate that the I-gel is a reasonable alternative to the PLMA for controlled ventilation during laparoscopic gynecologic surgery.

Ultrasound-guided greater occipital nerve block for patients with occipital headache and short term follow up

Background The greater occipital nerve (GON) block has been frequently used for different types of headache, but performed with rough estimates of anatomic landmarks. Our study presents the values of the anatomic parameters and estimates the effectiveness of the ultrasound-guided GON blockade. Methods The GON was detected using ultrasound technique and distance from external occipital protuberance (EOP) to GON, from GON to occipital artery and depth from skin to GON was measured in volunteers. Patients with occipital headache were divided into two groups (ultrasound-guided block: group S, conventional blind block: group B) and GON block was performed. The same parameters were measured on group S and VAS scores were assessed at pretreatment, 1 week and 4 weeks after treatment on both groups. Results The GON had distance of 23.1 ± 3.4 mm (right) and 20.5 ± 2.8 mm (left) from EOP to GON. Its depth below the skin was 6.8 ± 1.5 mm (right) and 7.0 ± 1.3 mm (left). The distance from GON to occipital artery was 1.5 ± 0.6 mm (right) and 1.2 ± 0.6 mm (left) in volunteers. Initial VAS score of group S and group B patients were 6.4 ± 0.2 and 6.5 ± 0.2. VAS score of 4 weeks after injection were 2.3 ± 0.2 on group S and 3.8 ± 0.3 on group B (P = 0.0003). Conclusions The parameters measured in this study should be useful for GON block and ultrasound-guided blockade is likely to be a more effective technique than blind blockade in occipital headache treatment.

Stylet- or forceps-guided tube exchanger to facilitate GlideScope® intubation in simulated difficult intubations – a randomised controlled trial

The GlideScope® videolaryngoscope is widely used in the management of the difficult airway. However, passing the tracheal tube through the vocal cords can be awkward, and the use of a stylet to guide insertion is recommended. This randomised controlled trial evaluated a forceps‐guided tube exchanger as an alternative to the stylet to aid intubation with the GlideScope in patients undergoing anaesthesia, with a simulated difficult airway created by the application of a semi‐rigid cervical collar. Data were analysed from 178 patients randomly assigned to undergo intubation using either the stylet (n = 88) or a forceps‐guided tube exchanger (n = 90). All intubations were completed successfully, with first attempt rates of 93.2% using the stylet and 94.4% using the exchanger (p = 0.597). The mean (SD) intubation time was 67.8 (28.7) s in the stylet group and 66.1 (15.5) s in the forceps‐guided tube exchanger group (p = 0.11). The frequency of sore throat 1 h after extubation was 34.1% in the stylet group and 2.2% in the tube exchanger group (p < 0.001); 24 h after extubation the corresponding figures were 40.0% and 11.1% (p < 0.001). Using a forceps‐guided tube exchanger may offer an advantage over a stylet in guiding tracheal intubation when the GlideScope is used.

Peri-operative ketamine with the ambulatory elastometric infusion pump as an adjuvant to manage acute postoperative pain after spinal fusion in adults: a prospective randomized trial

Background In this study, we assessed the effectiveness of ketamine as an alternative to non-steroidal anti-inflammatory drugs (NSAID), to manage acute postoperative pain after spinal fusion when given intravenously via a patient-controlled analgesia (PCA) pump in which the dose was proportional to that of fentanyl. Methods Forty patients undergoing 1-2 level spinal fusion were enrolled in this study. Patients were intraoperatively randomized into two groups to receive intravenous PCA consisting either of fentanyl 0.4 µg/ml/kg (control group) or fentanyl 0.4 µg/ml/kg with ketamine 30 µg/ml/kg (ketamine group) after intravenous injection of a loading dose. The loading dose in the control group was fentanyl 1 µg/kg with normal saline equal to ketamine volume and in the ketamine group it was fentanyl 1 µg/kg with ketamine 0.2 mg/kg. The verbal numerical rating scale (NRS), fentanyl and ketamine infusion rate, and side effects were evaluated at 1, 24, and 48 hours after surgery. Results There were no significant differences in patient demographics, duration of surgery and anesthesia or intra-operative opioids administration. We did not find any significant differences in the mean infusion rate of intraoperative remifentanil or postoperative fentanyl or in the side effects between the groups, but we did find a significant difference in the NRS between the groups. Conclusions Based on our results, we conclude that a small dose of ketamine (0.5-2.5 µg/kg/min) proportional to fentanyl is not only safe, but also lowers postoperative pain intensity in patients undergoing spinal fusion, although the opioid-sparing effects of ketamine were not demonstrated.

Comparison of volume-controlled and pressure-controlled ventilation using a laryngeal mask airway during gynecological laparoscopy

Background Several publications have reported the successful, safe use of Laryngeal Mask Airway (LMA)-Classic devices in patients undergoing laparoscopic surgery. However, there have been no studies that have examined the application of volume-controlled ventilation (VCV) or pressure-controlled ventilation (PCV) using a LMA during gynecological laparoscopy. The aim of this study is to compare how the VCV and PCV modes and using a LMA affect the pulmonary mechanics, the gas exchange and the cardiovascular responses in patients who are undergoing gynecological laparoscopy. Methods Sixty female patients were randomly allocated to one of two groups, (the VCV or PCV groups). In the VCV group, baseline ventilation of the lung was performed with volume-controlled ventilation and a tidal volume of 10 ml/kg ideal body weight (IBW). In the PCV group, baseline ventilation of the lung using pressure-controlled ventilation was initiated with a peak airway pressure that provided a tidal volume of 10 ml/kg IBW and an upper limit of 35 cmH2O. The end-tidal CO2, the peak airway pressures (Ppeak), the compliance, the airway resistance and the arterial oxygen saturation were recorded at T1: 5 minutes after insertion of the laryngeal airway, and at T2 and T3: 5 and 15 minutes, respectively, after CO2 insufflation. Results The Ppeak at 5 minutes and 15 minutes after CO2 insufflation were significantly increased compared to the baseline values in both groups. Also, at 5 minutes and 15 minutes after CO2 insufflation, there were significant differences of the Ppeak between the two groups. The compliance decreased in both groups after creating the pneumopertoneim (P < 0.05). Conclusions Our results demonstrate that PCV may be an effective method of ventilation during gynecological laparoscopy, and it ensures oxygenation while minimizing the increases of the peak airway pressure after CO2 insufflation.

Effect of ketorolac and diclofenac on the impairment of endothelium-dependent relaxation induced by reactive oxygen species in rabbit abdominal aorta

Background Reactive oxygen species (ROS) induce lipid peroxidation and tissue damage in endothelium. We studied the influences of ketorolac and diclofenac on ROS effects using the endothelium of rabbit abdominal aorta. Methods Isolated rabbit aortic rings were suspended in an organ bath filled with Krebs-Henseleit (K-H) solution bubbled with 5% CO2 and 95% O2 at 37.5℃. After being stimulated to contract with phenylephrine (PE, 10-6 M), changes in arterial tension were recorded following the cumulative administration of acetylcholine (ACh, 3 × 10-8 to 10-6 M). The percentages of ACh-induced relaxation of aortic rings before and after exposure to ROS, generated by electrolysis of K-H solution, were used as the control and experimental values, respectively. The aortic rings were pretreated with ketorolac or diclofenac at the same concentrations (10-5 M to 3 × 10-4 M), and the effects of these agents were compared with the effects of ROS scavengers: catalase, mannitol, sodium salicylate and deferoxamine and the catalase inhibitor, 3-amino-1,2,4-triazole (3AT). Results Both ketorolac and diclofenac maintained endothlium-dependent relaxation induced by ACh in a dose-related manner inspite of ROS attack (P < 0.05 vs. control value). The 3AT pretreated ketorolac (3 × 10-3 M) group was decreased more significantly than un-pretreated ketorolac (P < 0.05). Conclusions These findings suggest that ketorlac and diclofenac preserve the endothelium-dependent vasorelaxation against the attack of ROS, in a concentration-related manner. One of the endothelial protection mechanisms of ketorolac may be hydrogen peroxide scavenging.

The optimal effect-site concentration of remifentanil for lightwand tracheal intubation during propofol induction without muscle relaxation

STUDY OBJECTIVE To determine the most suitable effect-site concentration of remifentanil during lightwand intubation when administered with a target-controlled infusion (TCI) of propofol at 4.0 μg/mL without neuromuscular blockade. DESIGN Prospective study using a modified Dixons up-and-down method. SETTING Operating room of an academic hospital. PATIENTS 28 ASA physical status 1 and 2 patients, aged 18-65 years, scheduled for minor elective surgery. INTERVENTIONS Anesthesia was induced by TCI propofol effect-site concentration to 4.0 μg/mL, and the dose of remifentanil given to each patient was determined by the response of the previously tested patient using 0.2 ng/mL as a step size. The first patient was tested at a target effect-site concentration of 4.0 ng/mL of remifentanil. If intubation was successful, the remifentanil dose was decreased by 0.2 ng/mL; if it failed, the remifentanil dose was increased by 0.2 ng/mL. Successful intubation was defined as excellent or good intubating conditions. MEASUREMENTS AND MAIN RESULTS The remifentanil effect-site concentration was measured. The optimal effect-site concentration of remifentanil for lightwand tracheal intubation during propofol induction using 2% propofol target effect-site concentration to 4 μg/mL was 2.16 ± 0.19 ng/mL. From probit analysis, the effect-site concentration of remifentanil required for successful lightwand intubation in 50% (EC50) and 95% (EC95) of adults was 2.11 ng/mL (95% CI 1.16-2.37 ng/mL) and 2.44 ng/mL (95% CI 2.20-3.79 ng/mL), respectively. CONCLUSION A remifentanil effect-site concentration of 2.16 ± 0.19 ng/mL given before a propofol effect-site concentration of 4 μg/mL allowed lightwand intubation without muscle relaxant.

The use of remifentanil to facilitate the insertion of the Cobra perilaryngeal airway.

BACKGROUND: The use of remifentanil before propofol administration facilitates the insertion of the Laryngeal Mask Airway. We designed the present study to determine whether remifentanil would also create more suitable conditions for providing Cobra Perilaryngeal airway (CobraPLA) insertion when administered with propofol. METHODS: Both remifentanil and propofol were given as effect-site target-controlled infusions. There were four groups of 25 patients each. The propofol effect-site concentration was set at 6 &mgr;g/mL in all groups. Group R1 received a target effect-site remifentanil concentration of 1 ng/mL, Group R2 received remifentanil at 2 ng/mL, Group R3 received remifentanil at 3 ng/mL, and Group R4 received remifentanil at 4 ng/mL before the induction of anesthesia with propofol. The ease of insertion of CobraPLA was graded by the following 3-point scale: Grade 1, excellent, no response to CobraPLA insertion; Grade 2, acceptable, gagging or swallowing with insertion of CobraPLA; Grade 3, poor, unable to open mouth or biting upon insertion of CobraPLA. RESULTS: The most patients ranked as excellent for the first CobraPLA insertion (Grade 1) were found in Group R4, which was significantly higher than Groups R1 and R2 (P < 0.01), whereas no significant difference was found when compared with Group R3. The duration of apnea showed a significant dose-related increase (P < 0.01), especially between Group R2 (median 2.95 min) and R3 (median 7.9 min), but there was no significant difference between Groups R3 and R4. The incidence of hypotension in Group R4 within 1 min after insertion of CobraPLA was significantly more than for Groups R1 and R2 (P < 0.01). No significant differences could be found between the incidence of hypotension between Group R3 and the other groups. The incidence of hypertension at 1 min postinsertion was significantly more common in Groups R1 and R2 than Groups R3 and R4 (P < 0.01). CONCLUSION: An effect-site concentration of remifentanil of 2 ng/mL provides excellent conditions for insertion of the CobraPLA on the first attempt with minimal hemodynamic perturbations and a shorter duration of apnea.

End-tidal concentration of sevoflurane for preventing rocuronium-induced withdrawal of the arm in pediatric patients

Background During induction of general anesthesia, the intravenous injection of rocuronium is often associated with withdrawal movement of the arm due to pain, and this abrupt withdrawal may result in dislodgement of the venous catheter, injury, or inadequate injection of rocuronium. We performed this study to evaluate the 50 and 95% effective end-tidal concentrations of sevoflurane (ETsev) for preventing rocuronium-induced withdrawal of the arm. Methods We conducted a prospective double-blind study in 31 pediatric patients. After free flow of lactated Ringers IV fluid was confirmed, anesthesia was induced in the patients by using 2.5% thiopental sodium (4 mg/kg) and sevoflurane (4 vol%) with 6 L/min of oxygen. When the target ETsev was reached, preservative-free 1% lidocaine (1.5 mg/kg) was intravenously injected during manual venous occlusion and rocuronium (0.6 mg/kg) was injected after lidocaine injection under free-flow intravenous fluid. A nurse who was an investigator and was blinded to the ETsev injected the rocuronium. The nurse evaluated the response. Results Non-withdrawal movement was observed in 5 out of 11 patients with ETsev 3.0 vol% and in 5 out of 6 patients with ETsev 3.5 vol%. By Dixons up-and-down method, the 50% effective concentration (EC50) of sevoflurane for non-withdrawal movement at rocuronium injection was 3.1 ± 0.4 vol%. A logistic regression curve of the probability of non-withdrawal movements showed that the 50% effective ETsev for abolishing withdrawal movement at rocuronium injection was 2.9 vol% (95% confidence interval [CI] 2.4-3.8 vol%) and the 95% effective ETsev was 4.3 vol% (95% CI 3.6-9.8 vol%). Conclusions This study showed that the 50 and 95% effective ETsev that prevent withdrawal movement at rocuronium injection are 2.9 and 4.3 vol%, respectively.

Comparison of volume-control and pressure-control ventilation during one-lung ventilation

BACKGROUND We hypothesized that pressure control ventilation allows a more even distribution in the lung and better maintenance of the mean airway pressure than is achieved with volume control ventilation. We try to compare the effect of pressure control ventilation (PC) with that of volume control ventilation without an end-inspiratory pause (VC) during one-lung ventilation (OLV) in an anesthetized, paralyzed patient for performing thoracopic bullectomy of the lung. METHODS We ventilated 20 patients with VC and PC after the insertion of a thoracoscope in continual order for, at least for 15 minutes, for each, VC and PC procedure. At the end of VC and PC, the respiratory mechanics, gasometrics, and hemodynamic parameters were measured and collected. RESULTS We found no significant differences between VC and PC except for the peak inspiratory airway pressure (PIP), the mean airway pressure and the arterial oxygen partial pressure (PaO2). The PIP was significantly decreased from 27.0 +/- 6.0 cmH2O (VC) to 21.8 +/- 5.4 cmH2O (PC). The mean airway pressure was significantly increased from 8.6 +/- 1.6 cmH2O (VC) to 9.4 +/- 2.0 cmH2O (PC), and the PaO2 was significantly increased from 252.9 +/- 97.3 mmHg (VC) to 285.2 +/- 103.8 mmHg (PC). CONCLUSIONS If PC allows mechanical ventilation with the same tidal volume and respiratory rate as VC during OLV, then PC significantly increases the PaO2 but this is not clinically significant, and the PC significantly decreases the PIP, which induces barotrauma or volutrauma when the PIP is excessively high.