Successful management of a patient with massive vocal fold granuloma with transglottal jet ventilation / 대한마취과학회지

No abstract available.

Sex Differences in Remifentanil Requirements for Preventing Cough during Anesthetic Emergence

PURPOSE: Target-controlled infusion (TCI) of remifentanil can suppress coughing during emergence from general anesthesia; nevertheless, previous studies under different clinical conditions recommend significantly different effective effect-site concentrations (effective Ce) of remifentanil for 50% of patients (EC50). The differences among these studies include type of surgery and patient sex. In recent years, study of sex differences in regards to anesthetic pharmacology has drawn greater interest. Accordingly, we attempted to determine the effective Ce of remifentanil for preventing cough for each sex under the same clinical conditions. MATERIALS AND METHODS: Twenty female and 25 male ASA physical status I-II grade patients between the ages of 20 and 46 years who were undergoing thyroidectomy were enrolled in this study. The effective Ce of remifentanil for preventing cough was determined for each sex using the isotonic regression method with a bootstrapping approach, following Dixon's up-and-down method. RESULTS: Isotonic regression with a bootstrapping approach revealed that the estimated EC50 of remifentanil for preventing coughing during emergence was significantly lower in females {1.30 ng/mL [83% confidence interval (CI), 1.20-1.47 ng/mL]} than in males [2.57 ng/mL (83% CI, 2.45-2.70 ng/mL)]. Mean EC50 in females was also significantly lower than in males (1.23+/-0.21 ng/mL vs. 2.43+/-0.21 ng/mL, p<0.001). Mean arterial pressure, heart rate, and respiratory rate over time were not significantly different between the sexes. CONCLUSION: When using remifentanil TCI for cough prevention during anesthetic emergence, patient sex should be a considered for appropriate dosing.

Usefulness of a Cook(R) airway exchange catheter in laryngeal mask airway-guided fiberoptic intubation in a neonate with Pierre Robin syndrome: A case report / 대한마취과학회지

The case of a 33-day-old boy with Pierre Robin syndrome using a Cook(R) airway exchange catheter in laryngeal mask airway-guided fiberoptic intubation is presented. After induction with sevoflurane, classical reusable laryngeal mask airway (LMA) #1 was inserted and ultrathin fiberoptic bronchoscope (FOB) was passed through. A Cook(R) airway exchange catheter (1.6 mm ID, 2.7 mm OD) was passed through the LMA under the guidance of the FOB but failed to enter the trachea despite many trials. Then, an endotracheal tube (3.0 mm ID) was mounted on the FOB and railroaded over the FOB. After successful intubation, the Cook(R) airway exchange catheter was placed in the midtrachea through the lumen of the endotracheal tube. Even though the tracheal tube was accidentally displaced out of the trachea during LMA removal, the endotracheal tube could be easily railroaded over the airway exchange catheter.

Ionic Mechanisms of Desflurane on Prolongation of Action Potential Duration in Rat Ventricular Myocytes

PURPOSE: Despite the fact that desflurane prolongs the QTC interval in humans, little is known about the mechanisms that underlie these actions. We investigated the effects of desflurane on action potential (AP) duration and underlying electrophysiological mechanisms in rat ventricular myocytes. MATERIALS AND METHODS: Rat ventricular myocytes were enzymatically isolated and studied at room temperature. AP was measured using a current clamp technique. The effects of 6% (0.78 mM) and 12% (1.23 mM) desflurane on transient outward K+ current (I(to)), sustained outward current (I(sus)), inward rectifier K+ current (I(KI)), and L-type Ca2+ current were determined using a whole cell voltage clamp. RESULTS: Desflurane prolonged AP duration, while the amplitude and resting membrane potential remained unchanged. Desflurane at 0.78 mM and 1.23 mM significantly reduced the peak I(to) by 20+/-8% and 32+/-7%, respectively, at +60 mV. Desflurane (1.23 mM) shifted the steady-state inactivation curve in a hyperpolarizing direction and accelerated inactivation of the current. While desflurane (1.23 mM) had no effects on I(sus) and I(KI), it reduced the L-type Ca2+ current by 40+/-6% (p<0.05). CONCLUSION: Clinically relevant concentrations of desflurane appear to prolong AP duration by suppressing Ito in rat ventricular myocytes.

Caudal analgesia reduces the sevoflurane requirement for LMA removal in anesthetized children / 대한마취과학회지

BACKGROUND: An anesthetic state can reduce adverse airway reaction during laryngeal mask airway (LMA) removal in children. However, the anesthetic state has risks of upper airway obstruction or delayed emergence; so possibly less anesthetic depth is advisable. Caudal analgesia reduces the requirement of anesthetic agents for sedation or anesthesia; it is expected to reduce the sevoflurane requirement for LMA removal. Therefore, we determined the EC(50) of sevoflurane for LMA removal with caudal analgesia and compared that to the EC(50) without caudal analgesia. METHODS: Forty-three unpremedicated children aged 1 to 6 yr were enrolled. They were allocated to receive or not to receive caudal block according to their parents' consent. General anesthesia were induced and maintained with sevoflurane and oxygen in air. EC(50) of sevoflurane for a smooth LMA removal with and without caudal analgesia were estimated by the Dixon up-and-down method. The LMA was removed when predetermined end-tidal sevoflurane concentration was achieved, and the sevoflurane concentration of a subsequent patient was determined by the success or failure of the previous patient with 0.2% as the step size; success was defined by the absence of an adverse airway reaction during and after LMA removal. EC(50) of sevoflurane with caudal block, and that without caudal block, were compared by a rank-sum test. RESULTS: The EC(50) of sevoflurane to achieve successful LMA removal in children with caudal block was 1.47%; 1.81% without caudal block. The EC(50) were significantly different between the two groups (P < 0.001). CONCLUSIONS: Caudal analgesia significantly reduced the sevoflurane concentration for a smooth LMA removal in anesthetized children.

Effects of propofol on beta-adrenoceptor-mediated signal transduction in cardiac muscle; role of cAMP / 대한마취과학회지

BACKGROUND: Propofol may decrease myocardial contractility via actions on the beta-adrenoceptor-mediated signal transduction. The aim of this study was to evaluate the effect of propofol via beta-adrenoceptor-mediated signal transduction by measuring the tissue levels of cAMP (cyclic adenosine monophosphate). METHODS: The effects of propofol on beta-adrenoceptor mediated cascades were measured with cAMP concentrations, which were stimulated by agonists (l-isoproterenol, GTPgammaS, and forskolin) of each step of beta-adrenoceptor-mediated cascades. RESULTS: While the production of cAMP stimulated by isoproterenol, GTPgammaS, or forskolin are increased (P < 0.05), application of each concentration of propofol (0.1, 1, 10, 100 micrometer) did not alter the levels of cAMP. CONCLUSIONS: Considering that propofol did not alter the tissue cAMP levels when stimulated by isoproterenol, GTPgammaS, and forskolin, propofol appears to have no effect on the beta-adrenoceptor signaling pathway in guinea pig ventricular myocardium.

Cardioprotection Via Modulation of Calcium Homeostasis by Thiopental in Hypoxia-Reoxygenated Neonatal Rat Cardiomyocytes

PURPOSE: Ca2+ homeostasis plays an important role in myocardial cell injury induced by hypoxia-reoxygenation, and prevention of intracellular Ca2+ overload is key to cardioprotection. Even though thiopental is a frequently used anesthetic agent, little is known about its cardioprotective effects, particulary in association with Ca2+ homeostasis. We investigated whether thiopental protects cardiomyocytes against hypoxia-reoxygenation injury by regulating Ca2+ homeostasis. MATERIALS AND METHODS: Neonatal rat cardiomyocytes were isolated. Cardiomyocytes were exposed to different concentrations of thiopental and immediately replaced in the hypoxic chamber to maintain hypoxia. After 1 hour of exposure, a culture dish was transferred to the CO2 incubator and cells were incubated at 37degrees C for 5 hours. At the end of the experiments, the authors assessed cell protection using immunoblot analysis and caspase activity. The mRNA of genes involved in Ca2+ homeostasis, mitochondrial membrane potential, and cellular Ca2+ levels were examined. RESULTS: In thiopental-treated cardiomyocytes, there was a decrease in expression of the proapoptotic protein Bax, caspase-3 activation, and intracellular Ca2+ content. In addition, both enhancement of anti-apoptotic protein Bcl-2 and activation of Erk concerned with survival were shown. Furthermore, thiopental attenuated alterations of genes involving Ca2+ regulation and significantly modulated abnormal changes of NCX and SERCA2a genes in hypoxia-reoxygenated neonatal cardiomyocytes. Thiopental suppressed disruption of mitochondrial membrane potential (Delta Psi m) induced by hypoxia-reoxygenation. CONCLUSION: Thiopental is likely to modulate expression of genes that regulate Ca2+ homeostasis, which reduces apoptotic cell death and results in cardioprotection.

Comparison of ramosetron and ondansetron for preventing postoperative nausea and vomiting following spine surgery in highly susceptible patients / 대한마취과학회지

BACKGROUND: Opioid based patient-controlled analgesia (PCA) effectively provides adequate pain control after spine surgery, often at the expense of high incidence of postoperative nausea and vomiting (PONV). This study was designed to compare the effect of ramosetron with ondansetron for preventing PONV in highly susceptible patients using PCA following spine surgery under general anesthesia. METHODS: Seventy female patients, aged 18 to 65, scheduled for elective lumbar spine surgery, were randomly allocated into either ondansetron group (Group O, n = 35) or ramosetron group (Group R, n = 35). In patients assigned to group O, ondansetron 4 mg was injected and 12 mg was added to the PCA regimen. In patients assigned to group R, ramosetron 0.3 mg was injected and 0.3mg was added to the PCA regimen. The PCA regimen consisted of fentanyl 25microgram/kg (total volume including saline: 100 ml) and was programmed to deliver 2 ml/hr as background infusion and 0.5 ml per demand with a 15 min lockout. The incidence and severity of PONV, pain score, total amount of administered rescue analgesic and rescue antiemetic were assessed following 48 hrs after surgery. RESULTS: The incidence of PONV showed no significant differences between groups during 48 hrs after surgery. There were no differences in the severity of nausea, pain score, total amount of administered rescue analgesic and rescue antiemetic between groups. CONCLUSIONS: Ramosetron prophylaxis for preventing PONV is as effective as ondansetron in highly susceptible patients using fentanyl based PCA following spine surgery under general anesthesia.

Acute Heart Failure Induced by a beta-blocker after the Local Infiltration of Epinephrine: A case report / 대한마취과학회지

Topical epinephrine can cause severe hypertension, ventricular tachycardia, myocardial ischemia, cardiac arrest or pulmonary edema. The increased blood pressure and left ventricular afterload, as well as decreased left ventricular compliance caused by epinephrine may also decrease the cardiac output. If a beta blocker is used in these situations, the resulting decreased contractility and inability to increase the heart rate may further compromise the cardiopulmonary function. A 26 year-old man developed tachycardia and hypertension following the local infiltration of epinephrine 2 ml (1:10,000) around the nasal mucosa and an intramucosal injection of epinephrine 7.2 ml (1:100,000). He was treated with intravenous esmolol 10 mg. He showed a decreasing heart rate and blood pressure, depressed ST segments and inverted T waves. At the same time, the pulsation of the femoral arteries was not palpable. Cardiac massage was started. He was treated with intravenous atropine 0.5 mg and epinephrine 5microgram. He recovered from circulatory failure after this treatment and his ECG showed a normal sinus rhythm.

Electrophysiologic Mechanisms of Sevoflurane on Prolongation of the QT Interval: K+ Currents in Rat Ventricular Myocytes / 대한마취과학회지

BACKGROUND: Whereas sevoflurane (SEVO) has been reported to prolong the QT interval, little has been known on the electrophysiologic effects of SEVO which contributes to the prolongation of action potential (AP) duration. METHODS: The ventricular myocytes were obtained from enzymatically treated rat hearts. The standard whole cell voltage-clamp methods were used. The AP was measured using current clamp technique. As a repolarizing K+ current, the transient outward K+ current (I(to)), the sustained outward K+ current (I(sus)), and the inwardly rectifying K+ current (I(kI)) were measured. The L-type Ca2+ current (I(Ca), L) was also obtained. After the baseline measurements, the myocytes were exposed to 1.7 and 3.4% SEVO. SEVO concentrations in Tyrode superfusate at room temperature were 0.35 and 0.7 mM for 1.7 and 3.4% SEVO, respectively. Results are mean +/- SEM. RESULTS: SEVO prolonged the AP duration, while the amplitude and the resting membrane potential remained unchanged. At membrane potential of +60 mV, peak I(to) was significantly reduced by 18 +/- 2 and 24 +/- 2% by 0.35 and 0.7 mM SEVO, respectively. 0.7 mM SEVO did not shift the steady-state inactivation curve. Isus was unaffected by 0.7 mM SEVO. The I(kI) at -130 mV was little altered by 0.7 mM SEVO. I(Ca), L was significantly reduced by 28 +/- 3 and 33 +/- 1% by 0.35 and 0.7 mM SEVO, respectively. CONCLUSIONS: Prolongation of AP duration by SEVO in rat ventricular myocytes is likely to be caused by a reduction of I(to). Resting membrane potential was unaffected by SEVO, which seems to be related to no alteration of I(kI).

Electrophysiologic Effect of Desflurane on the Prolongation of Action Potential Duration in Ventricular Myocytes / 대한마취과학회지

BACKGROUND: Desflurane has been reported to prolong the QTc. Several ionic currents that contribute to the prolongation of the action potential (AP) duration were investigated using guinea pig (GP) and rat ventricular myocytes. METHODS: The normal APs were measured in isolated GP papillary muscles at 37 degrees C. Ventricular myocytes were obtained from GP and rat hearts. Both the delayed outward K+ current (I(K)) and the inward rectifier K+ current (I(KI)) were assessed using a voltage ramp protocol. A more detailed study on the I(K) was performed. The ICa, L was measured. In the rat ventricular myocytes, the transient outward K+ current (I(to)) was obtained. All the patch clamp experiments were carried out at room temperature. The values are presented as mean +/- SD. RESULTS: 0.91 mM desflurane significantly prolonged the APD in the GP ventricular myocytes. Using a linear voltage ramp protocol, the I(KI) at -130 mV and the peak outward I(KI) at -60 to -50 mV were not found to be significantly reduced by 0.78 and 1.23 mM desflurane, respectively. However, the peak outward I(K) at +60 mV was significantly reduced to 63 +/- 19% and 58 +/- 12% of the baseline by 0.78 and 1.23 mM desflurane, respectively. At a membrane potential of +60 mV, 0.78 and 1.23 mM desflurane reduced the Ito to 80 +/- 8% and 68 +/- 7%, respectively. A concentration-dependent reduction in the ICa, L was observed. CONCLUSIONS: The prolongation of the APD induced by clinically relevant concentrations of desflurane in GP and rat ventricular myocytes is most likely the result of I(K) and I(to) suppression.

Effect of Thiopental on Transient Outward Current (Ito) and Inwardly Rectifying K+ Current (Ik1) in Rat Ventricular Myocytes / 대한마취과학회지

BACKGROUND: Patients with the long QT syndrome, either congenital or acquired, have an increased development of serious ventricular arrhythmia, Torsade de Pointes. Thiopental (5 mg/kg) has been reported to prolong the QTc interval in patients undergoing surgery with normal repolarization. Recent studies have indicated that the clinical concentration of thiopental prolonged the action potential duration (APD), which was attributed to inhibition of the delayed rectifier (Ik) and/or the inward rectifier (Ik1) at various animal myocardial preparations. The rat ventricular cells were used to study the contribution of transient outward current (Ito) and Ik1 because they possess a variety of K+channel subtypes including Ito and Ik1 with little or no Ik, similar to those of human ventricular myocytes. The effect on Ca2+ current (ICa,L), which can alter the K+ conductance, was also observed. METHODS: With approval of the animal research committee in Yonsei University Medical College, isolated ventricular cells were obtained from enzymatically treated rat hearts. The ICa,L was elicited from a holding potential of -40 mV to + 60 mV under the modified Tyrode solution. Ik1 was obtained from a holding potential of -40 mV before their membrane potential was changed from -130 to + 50 mV. Ito was recorded during depolarizing steps from -80 mV followed by inactivation of Na+current by short pulses to -40 mV and then depolarized with 10 mV increments to test potentials up to + 60 mV. ICa,L was blocked by adding 0.5 mM CdCl2 during measurement of Ito. Normal action potential was measured using conventional microelectrode technique. RESULTS: At membrane potential of +60 mV, 50microM thiopental caused modest depression of Ito to 82 +/- 1% of control. From the dose-response curve from 1 to 1000microM, the IC50 of thiopental was 163microM. While 50microM thiopental caused modest depression of Ik1 of 87 +/- 2% of control at a test potential of -130 mV, no depression was observed from -110 mV to + 50 mV. ICa,L was significantly reduced to 57 +/- 5% of control. The APD90 was prolonged by 76% following application of 50microM thiopental. CONCLUSIONS: Prolongation of APD induced by thiopental was associated with reduction of Ito. Considering the high current density of Ito in rat ventricular myocytes, inhibition of Ito seems to play a major role in thiopental-induced APD prolongation.

Anesthetic Management of a Patient with Congenital Long QT Syndrome: A case report / 대한마취과학회지

Long QT syndrome is characterized by syncope and fatal ventricular arrhythmia or fibrillation at an young age. A 25-year-old female patient with congenital Long QT syndrome (Jervell and Lange-Nielsen syndrome) was scheduled for cochlea implantation due to congenital deafness. During anesthetic induction, maintenance, and emergence of these patients, cardiac arrests have been reported, which may be due to asymmetrical adrenergic stimuli in the heart, especially in unrecognized cases. Beta blocker is the first-line therapeutic drug for long QT syndrome. However, there is a controversy with regard to which anesthetics are safe for the management of patients with long QT syndrome. This case report describes an anesthetic management of a patient with congenital long QT syndrome who was treated with beta blocker.

Direct Myocardial Depressant Effect of Desflurane: Mechanical and Electrophysiological Actions in Vitro / 대한마취과학회지

BACKGROUND: Desflurane actions on myocardial contractility and cellular electrophysiologic behavior were studied in isolated guinea pig and rat right ventricular papillary muscles. METHODS: The isometric force of isolated guinea pig ventricular papillary muscles was studied in normal and 26 mM K+ Tyrode's solution at various stimulation rates. Experiments using rat papillary muscles under normal Tyrode's solution at the rested-state (RS) and using guinea pig papillary muscles under low Na+ Tyrode's solution (25 mM) were performed to evaluate the effect of Ca2+ release from the sarcoplasmic reticulum (SR). Effects of desflurane on SR function in situ were examined by its effect on rapid cooling contractures (RCCs). Normal and slow action potentials (APs) were evaluated by using a conventional microelectrode technique. Finally, Ca2+ currents of isolated guinea pig ventricular myocytes were examined using the whole cell patch clamp technique. RESULTS: 1 MAC (minimum alveolar concentration: 6%) and 2 MAC desflurane were applied. 1 MAC and 2 MAC desflurane depressed guinea pig myocardial contractions by ~30% and ~60%, respectively, from RS to 3 Hz stimulation rates. 1 MAC (1.15%) and 2 MAC isoflurane depressed peak force by ~25% and ~45%, respectively. Contractile force after rest in rat and guinea pig myocardium under low Na+ Tyrode's solution showed modest depression. In the partially depolarized, adrenergically stimulated myocardium, 1 MAC and 2 MAC desflurane caused a marked depression of the late peak force (1 MAC:~60%, 2 MAC:~80%) with moderate changes of the early peak force (1 MAC: ~20%, 2 MAC: ~40%). RCCs were abolished at 1 MAC desflurane. Desflurane did not alter the peak amplitude or maximum depolarization rate of normal and slow APs, however, AP duration was significantly prolonged. In isolated guinea pig myocytes at room temperature, 1 MAC and 2 MAC desflurane caused a ~28% and ~55% decrease in Ca2+ currents, respectively. CONCLUSIONS: These results indicate that desflurane causes a dose-dependent depression of contractile force in isolated myocardium, which is comparable to that of isoflurane. The depression seems to be related, at least in part, to its ability to reduce inward Ca2+ currents through the cardiac membrane. Therefore, it is likely that various methods employed to enhance inward Ca2+ current may improve the hemodynamic depression induced by desflurane.

Effect of Greater Occipital Nerve Block on the Posterior Headache and Neck Pain after Total Thyroidectomy / 대한마취과학회지

BACKGROUND: During thyroidectomy, the patient's neck is fully extended for good surgical exposure. After thyroidectomy, patients usually complain of posterior headache and posterior neck pain. It has been known that the greater occipital nerve block is a means of effective medical treatment for occipital headache and posterior neck pain. Therefore, we examined the effects of a greater occipital nerve block on postthyroidectomy headache and neck pain. METHODS: This study was randomized and double-blinded. After anesthesia induction, patients were administered greater occipital nerve block by the same anesthesiologist; 0.25% bupivacaine 5 ml was used for each greater occipital nerve block. Patients in the control group did not receive a greater occipital nerve block. After thyroidectomy, another anesthesiologist evaluated patients' headaches and neck pains at 4, 12, and 24 hours postoperatively by using a VAS. RESULTS: Forty four patients were included. The number of patients in the control and the block group were 27 and 17, respectively. VAS scores of occipital headache after 4, 12, and 24 hours in the control group were 3.52+/-2.75, 3.67+/-2.75, and 2.95+/-1.96, respectively. VAS scores of occipital headache after 4, 12, and 24 hours in the block group were 0.05+/-0.65, 0.50+/-0.85, and 0.43+/-0.64, respectively. VAS scores of posterior neck pain after 4, 12, and 24 hours in the control group were 4.09+/-2.79, 3.81+/-2.60, and 3.00+/-2.02. VAS scores of posterior neck pain after 4, 12, and 24 hours in the block group were 1.29+/-2.20, 1.00+/-1.66, and 0.79+/-1.25, respectively. The pain experienced by the block group was significantly lower than that of the control group. CONCLUSIONS: We conclude that greater occipital nerve block is an effective modality for reducing post-thyroidectomy headache and posterior neck pain.

Radial Nerve Paralysis due to Kent Retractor during Upper Abdominal Operation

After general anesthesia, peripheral nerve paralysis is a rare complication. The frequently damaged nerves including: branches of the brachial plexus, the ulnar, radial and common peroneal nerves, and sometimes the facial nerve. The radial nerve is the most infrequently damaged one, accounting for only 3% of nerve damage. We report a case of radial nerve paralysis due to self retractor during abdominal operation, its clinical findings, and review of the literature on peripheral nerve paralysis.

Radial Nerve Paralysis due to Kent Retractor during Upper Abdominal Operation

After general anesthesia, peripheral nerve paralysis is a rare complication. The frequently damaged nerves including: branches of the brachial plexus, the ulnar, radial and common peroneal nerves, and sometimes the facial nerve. The radial nerve is the most infrequently damaged one, accounting for only 3% of nerve damage. We report a case of radial nerve paralysis due to self retractor during abdominal operation, its clinical findings, and review of the literature on peripheral nerve paralysis.

The Direct Myocardial Depressant Effect of Naloxone in Vitro: Mechanical and Electrophysiological Actions / 대한구급학회지

BACKGROUND: Naloxone,an opioidant agonist, has been s hown t o have a c ar di ovascular pressor effect in states of hemorrhagic and endotoxic shock.We determined the direct inotropic effect of naloxone using guinea pig right ventricular papillary muscles. METHODS: With institutional approval,isometric contractile force was measured in normal and 26mM K+ Tyrode's solution at various stimulation rates.Normal and slow action potentials (APs) were measured with conventional microelectrode technique.The effects of naloxone on sarcoplasmic recticulum function were evaluated by measuring rapid cooling contractures (RCCs)in normal Tyrode 's solution and rested-state (RS)contraction in low Na+ (25 mM)Tyrode's solution.Patch clamp study was performed to examine the direct effect on Ca2+ current in myocytes. RESULTS: Naloxone (50,100,200 micro M)caused dose-dependent depression of peak force and maximal rate of peak force (dF/dt-max)by 30,50 and 70%,respectively.Modest depression was shown in RS contraction in low Na+ Tyrode's solution.In 26 mM K+ Tyrode's solution,100 micro M naloxone markedly depressed late force development.100 micro M naloxone depressed RCCs by 20%. While 100 micro M naloxone did not alter amplitude or dV/dt-max in normal and slow APs at 0.25 Hz, AP duration was prolonged significantly.In patch clamp study,50 micro M naloxone depressed Ca2+ current by 50%. CONCLUSIONS: Naloxone depresses contractile force.Myocardial depressant effect partly seems to be caused by depressed Ca2+ influx through cardiac membrane.Rapid release of Ca2+ from the sarcoplasmic reticulum by depolarization and release by rapid cooling seems to be minimally affected.

Fiberoptic Nasotracheal Intubation in Pediatric Patients with Difficult Mouth Opening: A case report / 대한마취과학회지

We present two pediatric patients, one with Pierre Robin syndrome and one with temporomandibular joint ankylosis with limited mouth opening. They had historical and physical evidence of airway obstruction, difficult feeding, and sleep disturbance. They were scheduled for oromaxillofacial surgery. In each case, two different-sized fiberoptic bronchoscopes were used for nasotracheal intubation. After loss of consciousness following an IV injection of ketamine or inhalation of sevoflurane while maintaining spontaneous respiration, 10% lidocaine was sprayed into one nostril. Following insertion of a 60 cm Olympus LF-2 fiberoptic bronchoscope (OD: 3.8 mm) through the same nostril without tube placement, the vocal cords were visualized and topical anesthesia of the larynx was achieved by spraying 2% lidocaine through the biopsy channel. Thirty seconds later, the bronchoscope was passed into the trachea and 2% lidocaine was sprayed intratracheally. Then, the bronchoscope was withdrawn. An endotracheal tube was advanced through the same nostril and positioned in the nasopharynx and the ultrathin fiberoptic bronchoscope (OD: 2.2 mm) was threaded through the tube. There was neither a cough nor laryngeal spasm during advancement of the tube into the trachea. Extubation was performed without compromise in the operating room. The patients were discharged uneventfully.

Development of Fine Time Controller of a Transtracheal Jet Ventilator and Its Experimental Application / 대한마취과학회지

BACKGROUND: Transtracheal jet ventilation (TTJV) with a large-bore angiocath that is inserted through the cricothyroid membrane can provide immediate oxygenation from a high pressure-oxygen wall outlet, as well as ventilation by means of manual triggering. However, there is widespread agreement that TTJV with a high pressure oxygen system may induce numerous complications including tracheal hemorrhage/ulceration, subcutaneous/mediastinal emphysema, and barotrauma resulting in a pneumothorax. The goal of this study was to highlight the potential effectiveness of a TTJ-ventilator with an oxygen supply pressure lower than 50 psig for proper oxygenation and ventilation avoiding the possibility of complications from a high pressure oxygen supply system. METHODS: Five mongrel dogs were intubated, paralyzed with vecuronium, and mechanically ventilated with enflurane in air maintaining the PaCO2 at 35 - 40 mmHg. A 16 G IV catheter was inserted percutaneously into the trachea below the tip of the endotracheal tube. We measured the injection volumes, entrained air volumes, and peak inflation pressures according to the changes of oxygen supply pressure (10 to 50 psig) with a fixed injection time (1 second). In addition, we evaluated the oxygenation effects of TTJV at 15 breaths per minute and an I : E 1 : 3 on 20 psig of oxygen supply pressure in hypoxic dogs. RESULTS: A 16 G angiocath provided the injected volumes from 139 ml to 595 ml according to the changes of oxygen pressure from 10 to 50 psig. The entrained air volumes were 6.7 48% of total inspirated volumes. The PaO2 was elevated over 300 mmHg and the PaCO2 was reduced to 45 mmHg within 1 minute of TTJV in hypoxic dogs. CONCLUSIONS: A TTJV system equipped with a time-controller and pressure-regulator can provide enough tidal volume to maintain oxygenation, and could minimize the volu/barotrauma of a conventional TTJV.