Jin-Hee Kim

Prophylactic dexamethasone decreases the incidence of sore throat and hoarseness after tracheal extubation with a double-lumen endobronchial tube.

BACKGROUND:Postoperative sore throat and hoarseness are common complications after tracheal intubation, particularly after using a double-lumen endobronchial tube (DLT). We conducted a prospective, randomized, double-blind, placebo-controlled study to evaluate the efficacy of dexamethasone for reducing the incidence and severity of postoperative sore throat and hoarseness. METHODS:One hundred sixty-six patients (aged 18–75 yr) scheduled for thoracic surgery with a DLT were enrolled. Before induction of general anesthesia, 0.1 mg/kg dexamethasone (Group D1), 0.2 mg/kg dexamethasone (Group D2), or a placebo (Group P) were infused IV in a double-blind and prospectively randomized manner. Glottic exposure as defined by Cormack and Lehane score, resistance to DLT insertion, number of intubation attempts, time to achieve intubation, and the duration of tracheal intubation were recorded. At 1 h and 24 h after tracheal extubation, the patients were evaluated for sore throat and hoarseness using a visual analog scale (VAS; where 0 = no pain and 100 = worst pain imaginable). RESULTS:One hour after tracheal extubation, the incidence of postoperative sore throat and hoarseness, along with the severity of sore throat were lower in Group D1 (31%, P = 0.021; 11%, P = 0.003; and VAS 12.4, P < 0.001, respectively) and D2 (11%, P = 0.001; 4%, P = 0.001; and VAS 6.6, P < 0.001, respectively) compared with Group P (53%, 36% and VAS 30.9, respectively). Twenty-four hours after tracheal extubation, the incidence of postoperative sore throat, hoarseness, and the severity of sore throat were significantly lower in Group D2 (27%, P = 0.002; 15%, P = 0.001; and VAS 29.9, P < 0.002, respectively) compared with Group D1 (47%, 31%, and VAS = 43.9, respectively) and Group P (57%, 45%, and VAS = 51.3, respectively). There was no complication associated with the dexamethasone administration. CONCLUSION:The prophylactic use of 0.2 mg/kg of dexamethasone significantly decreases the incidence and severity of sore throat and hoarseness 1 h and 24 h after tracheal extubation of a DLT.

The Influence of Head and Neck Position on the Oropharyngeal Leak Pressure and Cuff Position of Three Supraglottic Airway Devices

BACKGROUND: With supraglottic airway devices, such as the laryngeal tube suction (LTS), ProSeal laryngeal mask airway (PLMA) and Cobra perilaryngeal airway (CobraPLA), oropharyngeal leak pressure or cuff position may vary according to changes in the position of the head and neck. We evaluated oropharyngeal leak pressure and cuff pressure of the PLMA, LTS, and CobraPLA in different head and neck positions. METHODS: One-hundred-thirty-nine patients (aged 18-70 yr) scheduled for minor surgical procedures were randomly allocated to one of the supraglottic airway devices. Oropharyngeal leak pressure and cuff pressure were evaluated in four head and neck positions: neutral, 45° of flexion, 45° of extension, and 45° of right rotation. Adverse events (i.e., difficulty in ventilation or gastric insufflation) were assessed during the study. RESULTS: Leak pressures of the PLMA were lowest in the extension (18.5 vs 23.9 and 26.8 cm H2O of LTS and CobraPLA, respectively; P < 0.001) and in the rotation position (25.0 vs 29.4 and 28.5 cm H2O of LTS and CobraPLA, respectively; P < 0.005). With the CobraPLA, gastric insufflations occurred before the oropharyngeal leak in 37 of 45 patients. There were ventilatory difficulties in seven patients with LTS after neck flexion, which required tracheal intubation. CONCLUSIONS: The PLMA showed significantly lower oropharyngeal leak pressures than did the LTS or CobraPLA in the neck extension and rotation positions. Caution is warranted when changing the position of the head and neck when using the Cobra-PLA or LTS as gastric insufflation or ventilatory difficulty may occur.

A Comparative Study of Endotracheal Tube Positioning Methods in Children: Safety from Neck Movement

BACKGROUND:The unexpected displacement of the endotracheal tube (ETT) as a result of neck movements can cause endobronchial intubation and accidental extubation. The ETT is subject to movement even after its proper placement has been confirmed either clinically or radiographically. METHODS:One-hundred-seven children (2–8 yr) were divided randomly into three groups. In Group I, the ETT was entered into the main bronchus and withdrawn until equal sounds in both lung were heard, and then withdrawn 2 cm. In Group II, the ETT position was determined by placing the prescribed marks on the ETT at the level of the vocal cords, and in Group III, by palpating the ETT tip at the suprasternal notch. In all groups, the distance between the ETT tip and the carina was measured using a fiberoptic bronchoscope. The relative ETT tip position along the trachea (carina; 0%, vocal cords; 100%) was assessed in each position during neck movement. RESULTS:The relative position of the ETT with the patient in the neutral position in Groups I, II, and III was 21.4% ± 6.7%, 46.5% ± 13.0%, and 43.4% ± 11.1%, respectively. In Group I, the relative ETT position after flexion was 9.5% ± 10.3%, and endobronchial intubation was observed in five children (14.3%). There was no extubation or endobronchial intubation in the other two groups. CONCLUSIONS:Positioning the ETT by auscultation places the ETT more deeply than the midtrachea, which can increase the risk of endobronchial intubation during neck flexion.

Effects of Ethanol on the rat Glutamate excitatory amino acid transporter type 3 expressed in Xenopus oocytes: Role of protein kinase C and phosphatidylinositol 3-kinase

BACKGROUNDnGlutamate is a major excitatory neurotransmitter in the central nervous system. Glutamate transporters play a critical role in maintaining extracellular glutamate concentrations. We investigated the effects of ethanol on a neuronal glutamate transporter, excitatory amino acid transporter type 3 (EAAT3), and the role of protein kinase C (PKC) and phosphatidylinositol 3-kinase (PI3 K) in mediating these effects.nnnMETHODSnEAAT3 was expressed in Xenopus oocytes by injection of EAAT3 messenger RNA. By using a two-electrode voltage clamp, membrane currents were recorded after the application of l-glutamate. Responses were quantified by integration of the current trace and reported as microcoulombs. Data are mean +/- SEM.nnnRESULTSnEthanol enhanced EAAT3 activity in a concentration-dependent manner. At 25, 50, 100, and 200 mM of ethanol, the responses were significantly increased compared with control values. Kinetic study demonstrated that ethanol (50 mM) significantly increased Vmax (3.48 +/- 0.2 microC for control versus 4.16 +/- 0.24 microC for ethanol; n = 19; p < 0.05) without a significant change in the Km (65.6 +/- 11.1 microM for control versus 55.8 +/- 9.6 microM for ethanol; n = 19; p > 0.05) of EAAT3 for glutamate. Preincubation of the oocytes with phorbol-12-myristate-13-acetate (PMA) significantly increased EAAT3 activity (0.98 +/- 0.08 muC for control versus 1.28 +/- 0.09 microC for ethanol; n = 19; p < 0.05). However, there was no statistical difference among the responses of EAAT3 to PMA, ethanol, or PMA plus ethanol. Although the PKC inhibitors chelerythrine and staurosporine did not decrease the basal EAAT3 activity, they abolished the enhancement of EAAT3 activity by ethanol. Pretreatment with wortmannin, a PI3 K inhibitor, also abolished the ethanol-enhanced EAAT3 activity.nnnCONCLUSIONSnThese results suggest that acute ethanol exposure increases EAAT3 activity at clinically relevant concentrations and that PKC and PI3 K may be involved in mediating these ethanol effects.

A comparison of lighted stylet (Surch-Lite) and direct laryngoscopic intubation in patients with high Mallampati scores.

BACKGROUND: A lighted stylet is an effective alternative to a direct laryngoscope and has been reported to be particularly useful in patients with difficult airways. A high Mallampati class indicates poor visibility of the oropharyngeal structures. Because a lighted stylet does not require direct oropharyngeal visualization, we hypothesized that the lighted stylet would be easier to use than a direct laryngoscope in patients with a high Mallampati score. To examine our hypothesis, we performed a prospective, randomized study comparing a lighted stylet (Surch-Lite™) with direct laryngoscopy in patients with high Mallampati scores. Success rate, time required for intubation, and hemodynamic changes were compared. METHODS: Mallampati Class III patients were enrolled and were randomly assigned to the Surch-Lite group (Group SL) or the direct laryngoscopy group (Group DL). Patients tracheas were intubated with the randomly selected intubation device after induction of general anesthesia. Heart rate (HR) and mean arterial blood pressure were measured immediately before and every 30 s after intubation for 5 min. The time to intubation and success rate were recorded. Postoperative pharyngolaryngeal complaints were also assessed. RESULTS: Thirty patients were enrolled in each group. The success rate on the first attempt was significantly higher in Group SL (29 of 30) than in Group DL (24 of 30). The difference between maximal HR and baseline HR was significantly higher in Group DL (25 ± 13 bpm) than in Group SL (16 ± 10 bpm). The change in mean arterial blood pressure was also higher in Group DL (38 ± 14 mm Hg) than in Group SL (20 ± 13 mm Hg). The time to intubation was significantly shorter in Group SL (12 ± 6 s) than in Group DL (17 ± 12 s). Postoperative pharyngolaryngeal complaints were not significantly different between the two groups. CONCLUSIONS: The Surch-Lite showed a higher success rate on the first intubation attempt and produced an attenuated hemodynamic response to endotracheal intubation of patients with high Mallampati score. Thus, the Surch-Lite is an effective alternative to direct laryngoscopy in these patients.

A comparison of direct laryngoscopic views depending on pillow height

PurposeThis study was conducted to determine the optimal pillow height for the best laryngoscopic view.MethodsFifty patients were enrolled and preanesthetic airway evaluations were recorded. After induction of anesthesia, the Macintosh 3 blade was used for direct laryngoscopy without a pillow or with a pillow 3, 6, or 9xa0cm high in randomized order while the laryngeal view was imaged continuously on a monitor of the integrated video system. The best direct laryngoscopic view was sought for in each condition and graded by one anesthesiologist. The correlations between the preanesthetic airway assessments and the pillow height providing the best laryngoscopic view were analyzed.ResultsThe laryngoscopic view with the 9-cm pillow was significantly superior to that with other pillows and without a pillow (Pxa0<xa00.001). The incidence of difficult laryngoscopy (Cormack and Lehane grade 3) was 16% without a pillow. In these cases, laryngoscopic views were improved with a 9-cm pillow. In five patients with a short neck (<15xa0cm), better laryngoscopic view was observed with a 3- or 6-cm pillow compared with the 9-cm pillow. Neck length had a significant correlation (ρxa0=xa00.326, Pxa0=xa00.027) with the pillow height providing the best laryngoscopic views.ConclusionWe recommend the use of a 9-cm pillow during direct laryngoscopy in the sniffing position. In contrast, pillows <9xa0cm appear to be advantageous in short-necked patients.

The optimal depth of central venous catheter for infants less than 5 kg.

To avoid fatal complications of central venous catheterization such as cardiac tamponade, the tip of the central venous catheter (CVC) should be placed outside of the cardiac chamber. To suggest a guideline for a proper depth of CVC in infants, we measured the distance from the skin puncture site to the junction between superior vena cava and right atrium (SVC-RA junction) by using transesophageal echocardiography (TEE). Fifty infants less than 5 kg undergoing surgery for congenital heart disease were enrolled in this prospective study. After the induction of general anesthesia, CVC was inserted via the right subclavian vein. After the tip of the CVC was placed at the SVC-RA junction using TEE guidance, the length of the CVC inserted beneath the skin was measured. The measured distance had a high correlation with the patient’s height, weight, and age (r = 0.88, 0.76, and 0.64, respectively). In infants smaller than 5 kg, the following guideline can avoid intraatrial placement of the CVC: a depth between 40 and 45 mm for infants 2.0–3.0 kg in weight, 45–50 mm for those 3.0–3.9 kg, and 50–55 mm for those more than 4.0 kg.

Prophylactic milrinone during OPCAB of posterior vessels: implication in angina patients taking β-blockers

OBJECTIVEnTo determine whether a phosphodiesterase type 3 inhibitor can improve hemodynamics during off-pump coronary artery bypass grafting (OPCAB) of posterior vessels in patients on beta(1)-adrenoreceptor blockers.nnnMETHODSnThirty patients scheduled for OPCAB of the obtuse marginal artery (OM), and taking atenolol 100 mg a day were randomized in a double-blind manner to receive either milrinone or placebo. Hemodynamic data were obtained after induction, before pericardial incision, during left anterior descending artery grafting, during OM grafting, and after removal of the stabilizer. During the OM grafting, dopamine was infused when the cardiac index (CI) decreased below 2.0 L/min/m(2), and phenylephrine was infused to maintain the arterial pressure with a CI above 2.0 L/min/m(2).nnnRESULTSnDuring OM anastomosis, there were significant differences in CI (milrinone [M] = +7.7%, control [C] = -13.7%, p=0.01), SVI (M=-21.5%, C=-35.8%, p=0.03), SvO(2) (M=-2.6%, C=-8.9%, p=0.02), and SVR (M=-28.1%, C=+1.1%, p=0.01) between the two groups, in terms of percentage change from baseline value. Dopamine was required more frequently and at a higher dose in the control group (M=13%, 5.0 microg/kg/min; C=67%, 10.1 microg/kg/min, p<0.05). Phenylephrine was infused in 33% of the patients in the milrinone group compared to 13% in the control group (p>0.05).nnnCONCLUSIONSnProphylactic milrinone improves CI, SVI and SvO(2) reducing the need for high doses of dopamine during OM anastomosis in patients taking atenolol. Therefore, it can be used as an alternative to dopamine improving hemodynamics and organ perfusion during OPCAB of posterior vessels in patients on beta(1)-blockers.

The effect of tracheal tube size on air leak around the cuffs

Background This randomized single-blinded, cross-over study was done to evaluate the influence of the size of tracheal tubes on air leaks around the cuffs. Methods In a benchtop model, the number of longitudinal folds on the cuffs was evaluated for different sizes of tracheal tubes. In an anesthetized patient study, thirty patients scheduled for elective surgery under general anesthesia were included. After induction of anesthesia, the trachea was intubated with two sizes of tracheal tubes in a random sequence: in men, internal diameter of 7.5 mm and 8.0 mm; in women, internal diameter of 7.0 mm and 7.5 mm. After tracheal intubation with each tube, air leak pressures were evaluated at intracuff pressures of 20, 25 and 30 cmH2O by auscultation. To calculate the tracheal tube resistance (R), an inspiratory pause of 20% was applied and the resulting peak airway pressure (Ppeak), plateau pressure (Ppl) and mean expiratory tidal volume (Flow) were inserted in the formula R = (Ppeak - Ppl)/Flow. Results More longitudinal folds of the tracheal tube cuffs occurred in larger sized tubes compared to the smaller ones in a benchtop model. Air leakage was significantly less for the smaller tracheal tubes than for the larger ones for each gender at intracuff pressures of 20, 25 and 30 cmH2O. Tracheal tube resistances were not significantly altered by the size of tracheal tube. Conclusions The use of a smaller tracheal tube within an acceptable size can reduce air leakage around the cuff without significantly changing the tracheal tube resistance.

The Effect of Retrograde Autologous Priming of the Cardiopulmonary Bypass Circuit on Cerebral Oxygenation

OBJECTIVEnThe aim of this study was to investigate the effect of retrograde autologous priming (RAP) of the cardiopulmonary bypass (CPB) circuit on cerebral oxygenation.nnnDESIGNnA retrospective cohort study.nnnSETTINGnA university hospital.nnnPARTICIPANTSnNinety-four patients undergoing CPB.nnnINTERVENTIONSnCPB was primed with a RAP technique in the RAP group (n = 46) or with a conventional technique in the control group (n = 48).nnnMEASUREMENT AND MAIN RESULTSnCerebral oxygenation was monitored by measuring the regional cerebral oxygen saturation (rSO(2)). The rSO(2) and Hct values were compared between the groups during surgery. During the CPB period, the RAP group showed significantly higher values for rSO(2) (%) (immediately after the onset of CPB: 51.3 ± 8.4 and 56.3 ± 8.3; 30 minutes after the onset of CPB: 56.3 ± 5.1 and 59.7 ± 7.0; control group and RAP groups, respectively; p < 0.01 for each) and Hct (%) (immediately after the onset of CPB: 21.1 ± 3.7 and 23.1 ± 3.3; 30 minutes after the onset of CPB: 21.9 ± 3.7 and 23.3 ± 2.3; control group and RAP group, respectively; p < 0.02 for each). However, the 2 groups did not differ in rSO(2) (%) (67.2 ± 6.3 and 67.8 ± 6.4) or Hct (%) (27.8 ± 4.1 and 28.9 ± 3.6, control group and RAP group, respectively) at the end of the surgery.nnnCONCLUSIONSnThe application of RAP to CPB limits the degree of hemodilution and improves cerebral oxygenation during CPB. The present findings suggest a potential benefit of RAP from a neurologic aspect.