Sang Yun Cho

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.

Remifentanil used as adjuvant in general anesthesia for spinal fusion does not exhibit acute opioid tolerance

Background Although acute tolerance to opioids, especially to remifentanil, has been demonstrated consistently in animal studies, the results of clinical trials in humans are controversial. The aim of this study was to determine whether intraoperative infusions of remifentanil used as an adjuvant in general anesthesia result in acute tolerance, an event manifested by increased postoperative pain and a higher opioid requirement than usual. Methods Sixty patients who underwent surgery under general anesthesia for spinal fusion were randomly assigned to receive sevoflurane-nitrous oxide-oxygen (group SO, n = 20), sevoflurane-remifentanil-nitrous oxide-oxygen (group SR, n = 20), or propofol-remifentanil-oxygen (group PR, n = 20) in a double-blinded manner. All patients within 1 hour after induction received PCA (fentanyl 0.4 µg/kg/ml and ondansetron 16 mg) administered intravenously at a basal infusion rate of 1 ml/h, after being intravenously injected with a loading dose of fentanyl (1 µg/kg). Data for fentanyl requirement, verbal Numerical Rating Scale (NRS) pain score at rest, and presence of nausea or vomiting were collected at 1, 24, and 48 hours after surgery. Results We did not find any significant difference in postoperative PCA fentanyl requirements, NRS or side effects among the groups. Conclusions Remifentanil as an adjuvant to sevoflurane or propofol in general anesthesia for adults having surgery for spinal fusion does not appear to cause acute opioid tolerance or hyperalgesia in patients. However, further studies are needed to elucidate whether sevoflurane and propofol exert a clinically significant effect on opioid-induced tolerance or hyperalgesia and whether this effect is related to the age of the patient, the dose and duration of remifentanil given and the intensity of pain experienced postoperatively.

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.

Antioxidant effect of lidocaine and procaine on reactive oxygen species-induced endothelial dysfunction in the rabbit abdominal aorta.

Background Reactive oxygen species (ROS) induce lipid peroxidation and tissue damage in the endothelium. We tested the antioxidant effect of lidocaine and procaine on ROS-induced endothelial damage in the rabbit aorta. Methods Aortic rings isolated from rabbits were suspended in an organ bath filled with Krebs-Henseleit (K-H) solution bubbled with 5% CO2 and 95% O2 at 37.5℃. After precontraction with phenylephrine (PE, 10-6 M), changes in tension were recorded following a cumulative administration of acetylcholine (ACh 3 × 10-8 to 10-6 M). Differences were measured as percentages of ACh-induced relaxation of aortic rings before and after exposure to ROS as generated by electrolysis of the K-H solution. The aortic rings were pretreated with lidocaine or procaine (10-5 M to 3 × 10-3 M) to compare their effects, as well as ROS scavengers, catalase, mannitol, sodium salicylate, and deferoxamine, and a catalase inhibitor, 3-amino-1,2,4-triazole (3AT). Results Lidocaine and procaine dose-dependently maintained endothelium-dependent relaxation induced by ACh despite ROS activity (P < 0.05 vs control value). The 3AT pretreated procaine (3 × 10-3 M) group decreased more significantly than the un-pretreated procaine group (P < 0.05). Conclusions These findings suggest that lidocaine and procaine dose-dependently preserve endothelium-dependent vasorelaxation against ROS attack, potentially via hydrogen peroxide scavenging.

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.

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.

Awareness during general anesthesia due to the unlock position of the vaporizer − A report on two cases −

Awareness with recall after general anesthesia is a relatively infrequent occurrence and this awareness is often associated with significant adverse psychological sequelae, including posttraumatic stress disorder. The occurrence of awareness is often the consequence of the light anesthetic techniques with using minor anesthetic agents. Because the locking lever of the Penlon Sigma Delta Anesthetic vaporizer (sevoflurane) was at the unlock position, disconnection happened between the anesthetic machine and the vaporizer (the Selectatec(R) vaporizing system). In our two cases, the inhalation agents were not supplied and awareness with recall was identified after surgery. We recommend to check the concentration of the inhalation agents by monitoring the concentration of using endtidal inhalation agents and to measure the hypnotic level of anesthesia via the bispectral index (BIS) and the auditory evoked potential (AEP).

Development of bilateral tension pneumothorax under anesthesia in a Boerhaave's syndrome patient: a case report

A 33-year-old male visited the emergency room with abdominal pain which developed after a vomiting episode. Based on the pneumomediastinum findings from a chest radiograph and a contrast-enhanced chest and abdominal computed tomography scan, the patient was diagnosed with Boerhaaves syndrome. Preoperative radiologic findings showed no pneumothorax or pleural effusion. Once anesthesia was administered, the patient developed near complete cardiopulmonary collapse due to a bilateral tension pneumothorax, which was treated by bilateral thoracentesis, followed by chest tube insertion. Despite a left side rupture, the damaged right lung was unable to overcome single right ventilation, so the surgery was completed via right thoracotomy. The ruptured site was treated, and the patient was transferred to the intensive care unit. We discuss the anesthetic implications of this disease and how to prevent fatal complications.