Sungwon Na

Venous air embolism during total laparoscopic hysterectomy: comparison to total abdominal hysterectomy.

Background:Total laparoscopic hysterectomy (TLH) has become a widely accepted alternative to total abdominal hysterectomy (TAH). The aim of this study was to compare the incidence and grade of venous air embolism (VAE) in TLH to those in TAH using transesophageal echocardiography. Methods:Eighty-two American Society of Anesthesiologists physical status I patients scheduled for either TLH or TAH were enrolled. After induction of general anesthesia, a multiplane transesophageal echocardiography probe was inserted. The midesophageal four-chamber or bicaval view was continuously monitored. An independent transesophageal echocardiography–certified anesthesiologist graded VAE. Results:All patients undergoing TLH showed VAE, and 37.5% of patients had VAE grade higher than III. Fifteen percent of patients undergoing TAH showed VAE, and all of them were grade I. No patient in this study showed hemodynamic instability or electrocardiogram changes at the time of VAE occurrence. Most instances of VAE during TLH occurred during transection of the round ligament and dissection of the broad ligament. Conclusion:The incidence of VAE in patients undergoing TLH was 100%. VAE grade in TLH was higher compared to that in TAH, especially during transection of the round ligament and dissection of the broad ligament. Although the hemodynamic instability associated with VAE during TLH was not observed in this study, anesthesiologists must be vigilant for detection of VAE during TLH.

An evaluation of diaphragmatic movement by M-mode sonography as a predictor of pulmonary dysfunction after upper abdominal surgery.

BACKGROUND: Diaphragmatic dysfunction is a major factor in the etiology of postoperative pulmonary complications after upper abdominal surgery. M-mode ultrasonography is now an accepted qualitative method of assessing diaphragmatic motion in normal and pathological conditions. In this study, we evaluated whether diaphragmatic inspiratory amplitude (DIA) as measured by M-mode sonography can be a predictor of pulmonary dysfunction. METHODS: A prospective, single-center, single-unit, observational study was performed in 35 ASA physical status I and II nonsmoking patients undergoing open liver lobectomy. Diaphragmatic movements were assessed by M-mode sonography after a pulmonary function test preoperatively and on postoperative days (PODs) 1, 2, and 7. We measured the DIA (cm) during quiet, deep, and sniff breathing. RESULTS: After liver lobectomy, DIA during deep breathing and vital capacity (VC) showed significant reductions of 60% from their preoperative values on PODs 1 and 2 (P < 0.001). By POD 7, the variables recovered significantly, by 30% from the values on PODs 1 and 2 (P < 0.001). During deep breathing, DIA showed a significant correlation with VC (r = 0.839, P < 0.0001). The best cutoff values of DIA for detecting 30% and 50% decreases of VC from preoperative values, calculated by receiver operating characteristic analysis, were 3.61 and 2.41 cm, with sensitivity of 94% and 81% and specificity of 76% and 91%, respectively (P = 0.0001). Two patients showed postoperative diaphragmatic paralysis but did not complain of respiratory distress symptoms or need supplemental oxygen after being transferred to the general ward. CONCLUSIONS: DIA using M-mode sonography showed a linear correlation with VC measured by spirometry throughout the postoperative period. We conclude that using the M-mode sonographic technique at the bedside can be a practical way to investigate postoperative diaphragmatic dysfunction, and may also be an effective bedside screening method for diaphragmatic paralysis.

Targeting smooth emergence: the effect site concentration of remifentanil for preventing cough during emergence during propofol–remifentanil anaesthesia for thyroid surgery

BACKGROUND The administration of short-acting opioids can be a reliable and safe method to prevent coughing during emergence from anaesthesia but the proper dose or effect site concentration of remifentanil for this purpose has not been reported. We therefore investigated the effect site concentration (Ce) of remifentanil for preventing cough during emergence from anaesthesia with propofol-remifentanil target-controlled infusion. METHODS Twenty-three ASA I-II grade female patients, aged 23-66 yr undergoing elective thyroidectomy were enrolled in this study. EC(50) and EC(95) of remifentanil for preventing cough were determined using Dixons up-and-down method and probit analysis. Propofol effect site concentration at extubation, mean arterial pressure, and heart rate (HR) were compared in patients with smooth emergence and without smooth emergence. RESULTS Three out of 11 patients with remifentanil Ce of 1.5 ng ml(-1) and all seven patients with Ce of 2.0 ng ml(-1) did not cough during emergence; the EC(50) of remifentanil that suppressed coughing was 1.46 ng ml(-1) by Dixons up-and-down method, and EC(95) was 2.14 ng ml(-1) by probit analysis. Effect site concentration of propofol at awakening was similar in patients with a smooth emergence and those without smooth emergence, but HR and arterial pressure were higher in those who coughed during emergence. Clinically significant hypoventilation was not seen in any patient. CONCLUSIONS We found that the EC(95) of effect site concentration of remifentanil to suppress coughing at emergence from anaesthesia was 2.14 ng ml(-1). Maintaining an established Ce of remifentanil is a reliable method of abolishing cough and thereby targeting smooth emergence from anaesthesia.

Comparison of volume-controlled and pressure-controlled ventilation in steep Trendelenburg position for robot-assisted laparoscopic radical prostatectomy ☆

STUDY OBJECTIVE To compare the effects of volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) on respiratory mechanics and hemodynamics in steep Trendelenburg position. DESIGN Prospective, randomized clinical trial. SETTING University hospital. PATIENTS 34 ASA physical status 1 and 2 patients undergoing RLRP. INTERVENTIONS Patients were randomly allocated to either the VCV (n = 17) or the PCV group (n = 17). After induction of anesthesia, each patients lungs were ventilated in constant-flow VCV mode with 50% O(2) and tidal volume of 8 mL/kg; a pulmonary artery catheter was then inserted. After establishment of 30° Trendelenburg position and pneumoperitoneum, VCV mode was switched to PCV mode in the PCV group. MEASUREMENTS Respiratory and hemodynamic variables were measured at baseline supine position (T1), post-Trendelenburg and pneumoperitoneum 60 minutes (T2) and 120 minutes (T3), and return to baseline after skin closure (T4). MAIN RESULTS The PCV group had lower peak airway pressure (AP(peak)) and greater dynamic compliance (C(dyn)) than the VCV group at T2 and T3 (P < 0.05). However, no other variables differed between the groups. Pulmonary arterial pressure and central venous pressure increased at T2 and T3 (P < 0.05). Cardiac output and right ventricular ejection fraction were unchanged in both groups. CONCLUSIONS PCV offered greater C(dyn) and lower AP(peak) than VCV, but no advantages over VCV in respiratory mechanics or hemodynamics.

Rigid Laryngoscope-assisted Insertion of Transesophageal Echocardiography Probe Reduces Oropharyngeal Mucosal Injury in Anesthetized Patients

Background:Intraoperative transesophageal echocardiography has become a routine part of monitoring in patients with cardiac disease. However, insertion of a transesophageal echocardiography probe can be associated with oropharyngeal, esophageal, and gastric injuries. The purpose of this study was to determine whether insertion of a transesophageal echocardiography probe under direct laryngoscopic visualization can reduce the incidence of oropharyngeal mucosal injury. Methods:Eighty patients undergoing surgery with general anesthesia were randomly allocated to either the conventional group, in which the probe was inserted blindly, or the laryngoscope group, in which a rigid laryngoscope was used to visualize the passage of the probe. The incidence of oropharyngeal mucosal injury, the number of insertion attempts, and odynophagia were assessed. Results:There was no significant difference in demographic and hemodynamic parameters between the 2 groups. The incidence of oropharyngeal mucosal injury was higher in the conventional group than in the laryngoscope group (55% vs. 5%, P < 0.05). The incidence of odynophagia was higher in the conventional group than in the laryngoscope group (32.5% vs. 2.5%, P < 0.05). The number of insertion attempts was also higher in the conventional group than in the laryngoscope group. Conclusion:Rigid laryngoscope-assisted insertion of the transesophageal echocardiography probe reduces the incidence of oropharyngeal mucosal injury, odynophagia, and the number of insertion attempts.

Cervical Ganglion Block Attenuates the Progression of Pulmonary Hypertension via Nitric Oxide and Arginase Pathways

It has been recognized that the sympathetic nervous system is activated in pulmonary arterial hypertension (PAH), and abnormal sympathetic hyperactivity leads to worsening of PAH via endothelial dysfunction. The purpose of this study was to examine whether sympathetic ganglion block (SGB) can treat PAH by increasing the availability of nitric oxide (NO). PAH was induced in rats by 50 mg/kg of subcutaneous monocrotaline. After 2 weeks, daily injections of ropivacaine into the left superior cervical ganglion were repeated for 14 days (monocrotaline-SGB group). Monocrotaline group received sham SGB with saline, whereas control group received saline instead of monocrotaline. PAH was evident in monocrotaline group, with right ventricular systolic pressures (47±4 mm Hg) that were higher than those of controls (17±2 mm Hg), whereas SGB significantly attenuated monocrotaline-induced PAH (35±4 mm Hg). The right/left ventricular mass ratios exhibited similar changes to those seen with right ventricular pressures. Heart rate variability showed significantly higher sympathetic activity in the monocrotaline group. Microscopy revealed a higher proportion of muscular arteries with thicker medial walls in the monocrotaline group, which was attenuated by SGB. Monocrotaline induced arginase hyperactivity, which was in turn decreased by SGB-induced endothelial NO synthase activation. SGB restored monocrotaline-induced hypoactivity of superoxide dismutase. In conclusion, SGB could suppress PAH and the remodeling of pulmonary arteries via inactivation of arginase and reciprocal elevation of NO bioavailability, thus attenuating disproportionate hyperactivation of the sympathetic nervous system.

Improved sedation with dexmedetomidine–remifentanil compared with midazolam–remifentanil during catheter ablation of atrial fibrillation: a randomized, controlled trial

AIMS Anaesthesia is required for catheter ablation of atrial fibrillation (A-fib) to achieve patient comfort and immobilization to avoid map shifts. This study compared the analgesic and sedative efficacies of dexmedetomidine-remifentanil with those of midazolam-remifentanil for catheter ablation of A-fib. METHODS AND RESULTS Ninety patients were randomized to receive either intermittent midazolam boluses (1-2 mg) with 3.6-7.2 µg/kg/h of remifentanil (MR group) or dexmedetomidine 0.2-0.7 µg/kg/h after a loading dose of 1 µg/kg with 1.2-2.4 µg/kg/h of remifentanil (DR group). The sedation level assessed by the Ramsay sedation and bispectral index scores, haemodynamic variables, pain score (10-point numerical scale), and satisfaction levels of the patients and cardiologists (5-point numerical scale) were recorded. The Ramsay sedation score was significantly higher, and the bispectral index score was lower in the DR group (P< 0.001) compared with the MR group starting 10 min after drug administration. The incidence of desaturation (SpO2 < 90%) was significantly greater in the MR group compared with the DR group (15 vs. 1, P < 0.001). The pain score was significantly lower (1.72 ± 1.65 vs. 0.95 ± 1.10, P = 0.021), and the satisfaction levels of interventionists were significantly higher (2.50 ± 0.71 vs. 3.00 ± 0.63, P = 0.001) in the DR group compared with the MR group. CONCLUSION The combination of dexmedetomidine and remifentanil provided deeper sedation, less respiratory depression, better analgesia, and higher satisfaction for the interventionist during catheter ablation of A-fib compared with midazolam plus remifentanil, even at a lower dose of remifentanil.

Markers of poor outcome in patients with acute hypoxemic respiratory failure.

PURPOSE This study described the acute hypoxemic respiratory failure (AHRF) population and identified potential modifiable markers of outcome. METHODS A prospective, multicenter study was performed in 22 intensive care units (ICUs). The clinical outcomes of patients with acute respiratory distress syndrome (ARDS) were compared to the outcomes in patients with non-ARDS AHRF, and a propensity score matched analysis was performed. RESULTS A total 837 patients with an arterial oxygen tension/fraction of inspired oxygen ratio (Pao2/Fio2) less than 300 mm Hg on ICU admission were included. Of these, 163 patients met the criteria defining ARDS, whereas the remaining 674 patients who had unilateral or no pulmonary opacities were classified as non-ARDS AHRF. Baseline Pao2/Fio2 ratio, thrombocytopenia, increased positive end-expiratory pressure (PEEP) were significantly associated with the 60-day mortality in hypoxemic respiratory failure after multivariate analysis. However, ARDS was not associated with increased 60-day mortality when independent predictors for the 60-day mortality and propensity score were controlled. In the case-control study, the 60-day mortality rate was 38.6% in the ARDS group and 32.3% in the non-ARDS AHRF group. In both patients with ARDS and non-ARDS AHRF, the mortality rate increased proportionally to a lower baseline Pao2/Fio2. CONCLUSION Lower baseline oxygenation (Pao2/Fio2) is a poor prognostic marker in acute hypoxemic respiratory failure.

Validation of SAPS3 admission score and its customization for use in Korean intensive care unit patients: a prospective multicentre study.

To externally validate the simplified acute physiology score 3 (SAPS3) and to customize it for use in Korean intensive care unit (ICU) patients.

Dose-dependent attenuation by fentanyl on cough during emergence from general anesthesia

Although fentanyl suppresses tracheal tube‐induced cough during anesthetic recovery, it has not been proven if its antitussive effect is dose dependent and complication free. The purpose of this study is to evaluate the relationship between fentanyl doses and cough suppression during emergence from sevoflurane anesthesia.