Microvascular reactivity and endothelial glycocalyx degradation when administering hydroxyethyl starch or crystalloid during off-pump coronary artery bypass graft surgery: a randomised trial.

The infusion of fluids to patients may affect tissue microcirculation and the endothelial glycocalyx. However, the effects of hydroxyethyl starch and crystalloid on endothelial glycocalyx degradation and microvascular reactivity have not been evaluated in detail. We hypothesised that hydroxyethyl starch may cause less endothelial glycocalyx degradation and better microvascular reactivity than that caused by crystalloid. We randomly allocated 120 patients undergoing off-pump coronary artery bypass graft surgery to receive up to 20 ml.kg-1 of either hydroxyethyl starch 670/0.75 or crystalloid for intra-operative fluid resuscitation. Crystalloid was then infused to meet ongoing fluid requirements. During the peri-operative period, vascular occlusion tests were performed to assess microvascular reactivity, and serum syndecan-1 was measured as an index of endothelial glycocalyx degradation. The median (IQR [range]) fluid infused during surgery was significantly less in the hydroxyethyl starch group than the crystalloid group; 2800 (2150-3550 [1400-7300]) vs. 3925 (3100-4725 [1900-6700]) ml, respectively, p < 0.001. Vascular occlusion test parameters, including tissue oxygen saturation, occlusion and recovery slope did not differ significantly between the groups. Peri-operative changes in syndecan-1 were not significantly different between the groups. We conclude that, in patients undergoing off-pump coronary artery bypass graft surgery, compared with crystalloid, the use of hydroxyethyl starch 670/0.75 did not result in significant differences in microvascular reactivity or endothelial glycocalyx degradation.

The effects of thermal softening of double-lumen endobronchial tubes on postoperative sore throat, hoarseness and vocal cord injuries: a prospective double-blind randomized trial.

BACKGROUND: It is well known that thermal softening of polyvinyl chloride tracheal tubes reduces nasal damage during nasotracheal intubation. We hypothesized that thermal softening of double-lumen endobronchial tubes (DLTs) may be effective for reducing airway injury. This randomized double-blind study was performed to investigate whether thermal softening of DLTs decreased postoperative sore throat, hoarseness or vocal cord injuries. METHODS: Patients (n=140) undergoing one lung anaesthesia were randomized into two groups (n=70 each) depending on whether the DLT was softened by warming or not before tracheal intubation. The DLTs were placed in warm saline [40(1)°C] in the thermal softening group or in room temperature saline in the control group for 10 min. The vocal cords were examined by using flexible laryngoscopy immediately after extubation. Sore throat and hoarseness were evaluated for three postoperative days. The primary outcomes were the incidence of sore throat, hoarseness, and vocal cord injuries. RESULTS: Sore throat and vocal cord injuries occurred less frequently in the thermal softening group than in the control group [14/70 vs 27/70, risk ratio (95% CI): 0.52 (0.30-0.90), P=0.025 for sore throat; 15/70 vs 27/70, risk ratio (95% CI): 0.56 (0.32-0.95), P=0.042 for vocal cord injuries]. However, the incidence of hoarseness was comparable between the two groups. CONCLUSION: Tracheal intubation with DLTs softened by warming decreased the postoperative incidence of sore throat and vocal cord injuries. Therefore, thermal softening of DLTs before intubation seems to be helpful in reducing airway injuries associated with DLT intubation. CLINICAL TRIAL REGISTRATION: NCT 01626365.

Effects of Palonosetron on Perioperative Cardiovascular Complications in Patients Undergoing Noncardiac Surgery With General Anesthesia: A Retrospective Cohort Study.

We retrospectively investigated whether palonosetron administered during the induction of general anesthesia is associated with an increased risk of perioperative cardiovascular complications in a single tertiary center cohort consisting of 4,517 palonosetron-exposed patients and 4,517 propensity score-matched patients without palonosetron exposure. The primary endpoint was a composite of perioperative cardiovascular complications, including intraoperative cardiac arrhythmia, intraoperative cardiac death, and myocardial injury within the first postoperative week, and there was no significant difference between the groups (odds ratio [OR] = 1.04; 95% confidence interval [CI] = 0.92-1.19). As secondary endpoints, intraoperative cardioversion, cardiac compression, use of cardiovascular drugs, postoperative hospital stay, and in-hospital mortality showed no differences between the groups. However, the palonosetron group showed decreased intraoperative hypotension (OR = 0.88; 95% CI = 0.79-0.97) and length of postoperative intensive care unit (ICU) stay (4.26 ± 9.86 vs. 6.14 ± 16.75; P = 0.026). Palonosetron did not increase the rate of perioperative cardiovascular complications, and can therefore be used safely during anesthetic induction.

Remote preconditioning and major clinical complications following adult cardiovascular surgery: systematic review and meta-analysis.

BACKGROUND: A number of 'proof-of-concept' trials suggest that remote ischaemic preconditioning (RIPC) reduces surrogate markers of end-organ injury in patients undergoing major cardiovascular surgery. To date, few studies have involved hard clinical outcomes as primary end-points. METHODS: Randomised clinical trials of RIPC in major adult cardiovascular surgery were identified by a systematic review of electronic abstract databases, conference proceedings and article reference lists. Clinical end-points were extracted from trial reports. In addition, trial principal investigators provided unpublished clinical outcome data. RESULTS: In total, 23 trials of RIPC in 2200 patients undergoing major adult cardiovascular surgery were identified. RIPC did not have a significant effect on clinical end-points (death, peri-operative myocardial infarction (MI), renal failure, stroke, mesenteric ischaemia, hospital or critical care length of stay). CONCLUSION: Pooled data from pilot trials cannot confirm that RIPC has any significant effect on clinically relevant end-points. Heterogeneity in study inclusion and exclusion criteria and in the type of preconditioning stimulus limits the potential for extrapolation at present. An effort must be made to clarify the optimal preconditioning stimulus. Following this, large-scale trials in a range of patient populations are required to ascertain the role of this simple, cost-effective intervention in routine practice.

Relationship between early postoperative C-reactive protein elevation and long-term postoperative major adverse cardiovascular and cerebral events in patients undergoing off-pump coronary artery bypass graft surgery: a retrospective study.

BACKGROUND: Inflammation plays a key role in the pathogenesis of vascular occlusive diseases, such as myocardial infarction and stroke. Additionally, these conditions are predicted by C-reactive protein (CRP), a general inflammation marker. We hypothesized that the inflammation induced by surgery itself augments vascular occlusive disease. We retrospectively evaluated the relationship between postoperative CRP elevation and postoperative major adverse cardiovascular and cerebral events (MACCE) in patients undergoing off-pump coronary artery bypass surgery (OPCAB). METHODS: The electronic medical records of 1046 patients who underwent OPCAB were reviewed retrospectively. The relationship between postoperative serum CRP and long-term postoperative MACCE (median follow-up 28 months) was investigated. RESULTS: Patients were divided into quartiles according to maximum postoperative CRP levels (<18, 18-22, 22-27, ≥27 mg dl(-1)). The adjusted hazard ratios (HRs) were 2.15, 2.45, and 2.81, respectively (P=0.004), compared with the lowest quartile (<18 mg dl(-1)). In the multivariate analysis, the postoperative CRP quartile (HR 2.81; P=0.004), postoperative non-use of statins (HR 1.86; P=0.003), and postoperative maximum troponin I (HR 1.02; P<0.001) independently predicted postoperative MACCE, while preoperative CRP did not (P=0.203). Several parameters were correlated with postoperative maximum CRP level: body temperature (P=0.001) and heart rate (P<0.001) at the end of surgery; intraoperative last lactate (P<0.001) and base excess (P<0.001); and red blood cell transfusion (P=0.019). CONCLUSIONS: Postoperative CRP elevation was associated with long-term postoperative MACCE in OPCAB patients. This was mitigated by postoperative statin medication. Furthermore, postoperative CRP elevation was associated with intraoperative parameters reflecting hypoperfusion and inflammation.

A randomised controlled trial comparing incentive spirometry with the Acapella® device for physiotherapy after thoracoscopic lung resection surgery.

Lung resection surgery has been associated with numerous postoperative complications. Seventy-eight patients scheduled for elective video-assisted thoracoscopic lung resection were randomly assigned to receive standard postoperative care with incentive spirometry or standard care plus positive vibratory expiratory pressure treatment using the Acapella(®) device. There was no significant difference between incentive spirometry and the Acapella device in the primary outcome, forced expiratory volume in 1 s, on the third postoperative day, mean (SD) 53% (16%) vs 59% (18%) respectively, p = 0.113. Patients treated with both devices simultaneously found incentive spirometry to be less comfortable compared with the Acapella device, using a numeric rating scale from 1 to 5 with lower scores indicating higher comfort, median (IQR [range]) 3 (2-3 [2-4]) vs 1 (1-2 [1-3]) respectively, p < 0.001. In addition, 37/39 patients (95%) stated a clear preference for the Acapella device. Postoperative treatment with the Acapella device did not improve pulmonary function after thoracoscopic lung resection surgery compared with incentive spirometry, but it may be more comfortable to use.

Pulse pressure variation to predict fluid responsiveness in spontaneously breathing patients: tidal vs. forced inspiratory breathing.

We evaluated whether pulse pressure variation can predict fluid responsiveness in spontaneously breathing patients. Fifty-nine elective thoracic surgical patients were studied before induction of general anaesthesia. After volume expansion with hydroxyethyl starch 6 ml.kg(-1) , patients were defined as responders by a ≥ 15% increase in the cardiac index. Haemodynamic variables were measured before and after volume expansion and pulse pressure variations were calculated during tidal breathing and during forced inspiratory breathing. Median (IQR [range]) pulse pressure variation during forced inspiratory breathing was significantly higher in responders (n = 29) than in non-responders (n = 30) before volume expansion (18.2 (IQR 14.7-18.2 [9.3-31.3])% vs. 10.1 (IQR 8.3-12.6 [4.8-21.1])%, respectively, p < 0.001). The receiver-operating characteristic curve revealed that pulse pressure variation during forced inspiratory breathing could predict fluid responsiveness (area under the curve 0.910, p < 0.0001). Pulse pressure variation measured during forced inspiratory breathing can be used to guide fluid management in spontaneously breathing patients.

Effect of palonosetron on the QTc interval in patients undergoing sevoflurane anaesthesia.

BACKGROUND: Palonosetron is a recently introduced 5-HT3 receptor antagonist for postoperative nausea and vomiting. Detailed standardized evaluation of corrected QT (QTc) interval change by palonosetron under sevoflurane anaesthesia is lacking. We evaluated QTc intervals in patients who are undergoing surgery with sevoflurane anaesthesia and receive palonosetron. METHODS: Our study included 100 patients who were undergoing elective surgery under sevoflurane anaesthesia. The patients were randomly assigned to two groups: those who received an i.v. injection of palonosetron 0.075 mg immediately before induction of anaesthesia (pre-surgery group, n=50) and those who received it after surgery in the recovery room (post-surgery group, n=50). QTc intervals were measured before operation, intraoperatively (baseline, immediately after tracheal intubation, and at 2, 10, 15, 30, 60, and 90 min after administration of palonosetron or placebo), and after operation (before and at 3, and 10 min after administration of palonosetron or placebo). QTc intervals were calculated using Fridericia's, Bazett's, or Hodges formulas. RESULTS: The perioperative QTc intervals were significantly increased from the baseline values, but were not affected by the pre- or post-surgical timing of palonosetron administration. CONCLUSIONS: There was no significant difference in the QTc intervals during the perioperative period, whether 0.075 mg of palonosetron is administered before or after sevoflurane anaesthesia. Palonosetron may be safe in terms of QTc intervals during sevoflurane anaesthesia. Clinical trial registration ClinicalTrials.gov: NCT01650961.

Comparison of techniques for double-lumen endobronchial intubation: 90° or 180° rotation during advancement through the glottis.

BACKGROUND: During endobronchial intubation with a double-lumen endobronchial tube (DLT), the DLT is conventionally rotated through 90° when the bronchial tip is just past the vocal cords. This study was performed to investigate if rotation of the DLT through 180° decreases postoperative hoarseness, sore throat, or vocal cord injuries. METHODS: Patients (n=164) undergoing thoracic surgery were randomized into two groups. Just after the bronchial tip passed the glottis, left-sided DLTs were rotated 90° (Group 90, n=84) or 180° (Group 180, n=80) counterclockwise and advanced. In the Group 180, DLTs were re-rotated 90° clockwise after the tracheal tip passed the glottis. Resistance during the advance of DLTs was assessed. Hoarseness and sore throat were evaluated for three postoperative days. Vocal cords were examined on the first postoperative day. RESULTS: In nine patients allocated to Group 90, the DLT could not be advanced past the glottis because of severe resistance. There was less resistance to advancement of the DLT in Group 180 compared with Group 90 (P<0.001). The incidence of hoarseness was comparable between the two groups. Sore throat and vocal cord injuries occurred less frequently in Group 180 compared with Group 90 (20 vs 40%, P=0.008; 19 vs 47%, P=0.032). CONCLUSIONS: Rotation of a DLT through 180° facilitated its passage through the glottis and reduced the incidence of postoperative sore throat and vocal cord injuries.

A novel maneuver to blindly position bronchial blockers.

BACKGROUND: The use of a fiberoptic bronchoscope is fundamental to the positioning of bronchial blockers. However, a fiberoptic bronchoscope could be unavailable. We tried to devise a blind method to locate the blocker without help of a fiberoptic bronchoscope. METHODS: In 56 thoracic surgical patients requiring one-lung ventilation, a Uniblocker® was inserted into the endotracheal tube and advanced until the blocker balloon just protruded from the endotracheal tube tip. With inflation of the balloon, peak inspiratory pressure increased abruptly with disappearance of expiratory tidal volume. The blocker was advanced with its tip directed to one side until peak inspiratory pressure abruptly dropped and expiratory tidal volume re-appeared. Thereafter, the blocker was advanced 3 cm further with the cuff deflated. Using a fiberoptic bronchoscope, the position of the blocker was checked after re-inflation of the cuff. The entire procedure was repeated on the other side. RESULTS: Acceptable blocker placements were achieved on 48 of 56 (85.7%) right attempts; the right upper bronchus was not blocked in 5 cases and blocker positions were too shallow in 3. Only 33 of 56 (58.9%) left attempts were acceptable in that blockers could not be advanced into the left bronchus in 19 and were positioned too shallow in 4. CONCLUSION: This novel technique to blindly position bronchial blockers could be almost successful in isolating the right lung. However, isolation of the left lung was frequently unsuccessful in spite of several attempts.

Comparison of the neutral and retracted shoulder positions for infraclavicular subclavian venous catheterization: a randomized, non-inferiority trial.

BACKGROUND: There are controversies regarding the most efficient shoulder position during infraclavicular subclavian venous catheterization. We hypothesized that, regarding the success rate of subclavian venous catheterization, the neutral shoulder position would not be inferior to the retracted shoulder position. METHODS: A total of 362 patients who underwent elective surgery were randomly assigned to two groups: those who underwent subclavian venous catheterizations in the neutral shoulder position (neutral group, n=181) or in the retracted shoulder position (retracted group, n=181). In the retracted group, a 1 litre saline bag was placed longitudinally beneath the spinal column between the scapulae to allow the shoulders to fall into a 'retracted' position. The incidence of failures to place the central venous catheters and complications such as arterial puncture, pneumothorax, or haemothorax were recorded. RESULTS: The success rates were 95.6% (173/181) in the neutral group and 96.1% (174/181) in the retracted group. The difference of 0.5% was within the prespecified non-inferiority margin of 5% with a P-value of 0.017 [two-sided 95% confidence interval (CI), -0.036 to 0.047; upper limit of the 95% CI, 0.040]. There were four catheterization failures (2.2%) in the neutral group and two failures (1.1%) in the retracted group. Complication rates were not significantly different between the neutral and retracted groups [3/181 (1.7%) vs 4/181 (2.2%) for arterial punctures and 1/181 (0.6%) vs 1/181 (0.6%) for pneumothorax]. CONCLUSIONS: The neutral shoulder position was as effective as the retracted shoulder position for infraclavicular subclavian venous catheterization. Shoulder retraction does not appear to be necessary for the infraclavicular subclavian venous catheterization. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT01368692.

The effect of remote ischaemic preconditioning on myocardial injury in patients undergoing off-pump coronary artery bypass graft surgery.

In several recent clinical trials on cardiac surgery patients, remote ischaemic preconditioning (RIPC) showed a powerful myocardial protective effect. However the effect of RIPC has not been studied in patients undergoing off-pump coronary artery bypass graft surgery. We evaluated whether RIPC could induce myocardial protection in off-pump coronary artery bypass graft surgery patients. Patients undergoing elective off-pump coronary artery bypass graft surgery were randomly allocated to the RIPC (n = 65) or control group (n = 65). After induction of anaesthesia, RIPC was induced by four cycles of five-minute ischaemia and reperfusion on the upper limb using a pneumatic cuff. Anaesthesia was maintained with sevoflurane, remifentanil and vecuronium. Myocardial injury was assessed by troponin I before surgery and 1, 6, 12, 24, 48 and 72 hours after surgery. There were no statistical differences in troponin I levels between RIPC and control groups (P = 0.172). Although RIPC reduced the total amount of troponin I (area under the curve of troponin increase) by 26%, it did not reach statistical significance (RIPC group 53.2 +/- 72.9 hours x ng/ml vs control group 67.4 +/- 97.7 hours x ng/ml, P = 0.281). In this study, RIPC by upper limb ischaemia reduced the postoperative myocardial enzyme elevation in off-pump coronary artery bypass graft surgery patients, but this did not reach statistical significance. Further study with a larger number of patients may be needed to fully evaluate the clinical effect of RIPC in off-pump coronary artery bypass graft surgery patients.

Single ZnO nanobelt based field effect transistors (FETs).

Electrical properties of single ZnO nanobelt have been examined by fabricating single nanobelt based field effect transistors (FETs). The ZnO nanobelts were grown via non-catalytic simple thermal evaporation process by using metallic zinc powder in the presence of oxygen. The detailed structural and optical characterizations confirmed that the grown nanobelts are well-crystalline with the wurtzite hexagonal phase and exhibiting good optical properties. The passivation effect on the electrical characteristics of the as-grown nanobelts was also evaluated by passivating the fabricated FETs with polymethyl methacrylate (PMMA). The passivated single ZnO nanobelt based FETs exhibited higher electrical performance as compared to non-passivated FETs due to reduction in the physically absorbed chemisorbed species such as O-, O2-, O2, or OH- etc. The field effect mobility (micro(eff)) of the fabricated nanobelt based non-passivated and passivated FETs was estimated to be approximately 21.3 and 59 cm2/V x s, respectively. Moreover the carrier concentration and peak transconductance of the fabricated non-passivated and passivated FET were calculated to be approximately 8.73 x 10(17) and approximately 1.86 x 10(18) cm(-3) and approximately 0.76 and 1.4 microS, respectively. This work offers substantial opportunities for further practical electronics and photonics nanodevice applications of ZnO based nanostructures.

Tracheal shortening during laparoscopic gynecologic surgery.

BACKGROUND: During laparoscopic gynecologic surgery, pneumoperitoneum combined with the Trendelenburg position moves the carina towards the tip of the endotracheal tube (ETT), decreasing the margin of safety for the ETT position and increasing accidental endobronchial intubation. However, it remains to be established whether the tracheal length itself is actually changed. We conducted a prospective observational study to measure the change in the length of the trachea and the distance between the ETT tip and the carina in patients undergoing gynecologic laparoscopic surgery. METHODS: Twenty-three patients scheduled for laparoscopic gynecologic surgery were enrolled. In the neutral position, the tracheal length was measured using a fiberoptic bronchoscope. The distance between the ETT tip and the carina was also measured. The tracheal length and the distance between the ETT tip and the carina were measured again 10 min after carbon dioxide (CO(2)) pneumoperitoneum (12-14 mmHg) combined with the Trendelenburg position (15 degrees ). RESULTS: In the neutral position, the tracheal length was 11.09 +/- 0.90 cm and the distance between the ETT tip and the carina was 3.36 +/- 1.04 cm. After pneumoperitoneum combined with the Trendelenburg position, the distance between the ETT tip and the carina had decreased by 0.85 +/- 0.28 cm. The tracheal length had also decreased by 0.42 +/- 0.19 cm, which was equivalent to 49.7% of the decrease in the distance between the ETT tip and the carina. CONCLUSIONS: These results suggest that tracheal shortening may contribute to a decrease in the distance between the ETT tip and the carina, increasing the risk of accidental endobronchial intubation during laparoscopic gynecologic surgery.

[Signal and data acquisition based on waveform graph].

It is well known that signal acquisition is the first step in signal processing. A simple and convenient method of acquiring biologic data is described here, which needs no special acquisition equipment, and is practical and makes the data acquisition more credible.

Mitogen accumulation in von Recklinghausen neurofibromatosis.

Most, but not all, patients with von Recklinghausen neurofibromatosis develop tumors (neurofibromas) that contain large numbers of Schwann cells and fibroblasts. To begin to understand the molecular events that contribute to cell proliferation in these benign tumors, we have analyzed extracts of neurofibromas to determine whether they contain mitogens for Schwann cells or fibroblasts, or both. Schwann cell and fibroblast mitogens are present in neurofibroma extracts. All the neurofibromas analyzed contain a Schwann cell mitogen similar to a neuronal cell surface molecule known to stimulate Schwann cell proliferation during normal development; this mitogen also stimulates fibroblast proliferation. Basic fibroblast growth factor is present in 60% of tumors evaluated. Accumulation of mitogenic substances may contribute to the growth of neurofibromas.

The neuronal cell-surface molecule mitogenic for Schwann cells is a heparin-binding protein.

The cell surface of embryonic peripheral neurons provides a mitogenic stimulus for Schwann cells. We report (i) the solubilization of this mitogenic activity from rat dorsal root ganglion neurons grown in tissue culture and (ii) the solubilization and partial purification of mitogenic activity from neonatal rat brains. Extracted mitogenic activity is peripheral rather than intrinsic to the membrane, stable after extraction, and active as a mitogen in the absence of serum (the most stringent criterion defining the neuronal mitogen). We have previously provided evidence suggesting that a neuronal cell-surface heparan sulfate proteoglycan is required for expression of the neurons' mitogenic activity. We now show that mitogenic activity can be extracted from the membrane dissociated from proteoglycan as assayed by its ability to bind to immobilized heparin. After dissociation, low concentrations of heparin (1 micrograms/ml) inhibit the ability of the mitogen to stimulate Schwann cell division. Basic fibroblast growth factor (FGF) is weakly mitogenic for Schwann cells, but it is not present in mitogenic brain extracts (based on immunoblotting). Immunodepletion experiments with specific antibodies to FGF indicate that the mitogenic activity extracted from neurons is not a form of this heparin-binding mitogen. Acidic FGF is not mitogenic for Schwann cells and is not present in mitogenic brain extracts. We suggest that these and previous data indicate the neurite mitogen is a proteoglycan-growth factor complex that limits mitogenic activity to the axonal surface, protects mitogen against inactivation by other proteoglycans, and provides for effective presentation of mitogen to the Schwann cell.