PubMed Health⌕ Search

Biomedical subjects

E H C Liu

Publications and source records attributed to E H C Liu.

12 recordsLinked to original sources
PubMed2006

An evaluation of poor LMA CTrach views with a fibreoptic laryngoscope and the effectiveness of corrective measures.

BACKGROUND: The LMA CTrach++ system has integrated fibreoptics to enable viewing of the glottis to aid tracheal intubation via a laryngeal mask conduit. Earlier evaluations of this system had shown high success rates of insertion, ventilation and tracheal intubation, but frequent difficulty or failure to view the glottis. METHOD: We evaluated CTrach views in 100 patients. In 69 patients with partial or no views of the glottis, we evaluated the causes with the aid of an Olympus LF-DP fibreoptic laryngoscope passed through the CTrach. In those with poor views, we tested the effectiveness of simple corrective measures to improve the views and optimize CTrach placement. These included pushing the CTrach deeper in, partial withdrawal by 6 cm and reinsertion to correct epiglottic downfolding, withdrawal by 1 cm and applying forward lift to correct obstruction by the arytenoids, and complete removal to clean the fibreoptic ports followed by reinsertion when secretions were the problem. RESULTS: Downfolding of the epiglottis caused poor views in 57 patients, which was correctable in 51. Obstruction of the view by the arytenoids occurred in seven patients and by secretions in five, all of which were correctable. With the Ctrach, we were able to ventilate the lungs in all patients, view the glottis in 94 and intubate the trachea in 97 patients. CONCLUSION: Despite the ability to ventilate the lungs in all patients with the CTrach, poor initial views were very frequent, indicating suboptimal placement, although most poor views can be improved, leading to a high intubation success rate.

Adult↗
PubMed2006

The LMA CTrach, a new laryngeal mask airway for endotracheal intubation under vision: evaluation in 100 patients.

BACKGROUND: The LMA CTrach is a new laryngeal mask system consisting of an LMA CTrach Airway with integrated fibreoptic channels, and a detachable LMA CTrach Viewer. This system enables viewing of the larynx and aids endotracheal intubation through a laryngeal mask airway. Method. We used and evaluated this system in 100 adult patients undergoing general anaesthesia for elective surgery. Our primary outcomes were the success rates of LMA CTrach Airway insertion and endotracheal intubation with this system. RESULTS: We were able to insert the LMA CTrach Airway in and to ventilate all 100 patients. We were successful in endotracheal intubation, either under vision or blind, in 96 patients. We were able to view the larynx in 84 patients, but the quality of the best view obtained was very variable. The median (inter quartile range) time for the complete intubation process was 166 (114-233) s. The system allowed nearly continuous ventilation and oxygenation during the process. CONCLUSIONS: The LMA CTrach system has potential advantages over the LMA Fastrach system, including the ability to align the LMA outlet with the larynx and a high first intubation attempt success rate. However, it was difficult to view the larynx with the LMA CTrach compared with direct laryngoscopy, and expectations must be moderated.

Adult↗
PubMed2005

Evaluation of ease of intubation with the GlideScope or Macintosh laryngoscope by anaesthetists in simulated easy and difficult laryngoscopy.

The GlideScope is a new video laryngoscope developed for management of the difficult airway. We compared the GlideScope with the Macintosh laryngoscope in simulated easy and difficult laryngoscopy. Twenty anaesthetists were allowed three attempts to intubate in each of four laryngoscopy scenarios in a high fidelity simulator. In the simulated easy laryngoscopy scenarios, the anaesthetists took longer to intubate using the GlideScope than the Macintosh laryngoscope (mean (SD) 19.0 (9.7) s vs. 12.7 (5.9) s, respectively; p = 0.006). There was no difference in the number of successful intubations, ease of intubation or choice of intubating device. In the simulated difficult laryngoscopy scenarios, the anaesthetists took less time to intubate using the GlideScope (23.5 (12.7) s vs. 70.5 (101.2) s, respectively; p = 0.001). The slightly higher success rate with the GlideScope was not statistically significant (20/20 vs. 18/20, respectively; p = 0.5). However, the anaesthetists found it easier to intubate using the GlideScope (median (interquartile range [range]) 1 (1-2 [1-2]) vs. 2 (2-3 [1-3]), respectively; p < 0.0001).

Attitude of Health Personnel↗
PubMed2005

The teaching of anaesthesia in Singapore.

This article describes the development of undergraduate and postgraduate anaesthesia teaching and training in Singapore. Anaesthesia teaching has evolved from art and apprenticeship to become systematic, scientific and evidence-based, while retaining an emphasis on hands-on practical training. Simulator training provides unique advantages, which the University Department of Anaesthesia has utilised in integrated medical student teaching.

Anesthesiology↗
PubMed2004

Effects of isoflurane and propofol on cortical somatosensory evoked potentials during comparable depth of anaesthesia as guided by bispectral index.

BACKGROUND: The aim of this study was to determine if propofol caused less suppression of cortical somatosensory evoked potentials (SSEPs) during spine surgery compared with isoflurane during comparable depth of anaesthesia as guided by bispectral index (BIS) measurements. METHODS: This was a randomized controlled trial of propofol and isoflurane involving 60 patients undergoing elective spine surgery. BIS monitoring was used to guide a consistent and comparable depth of anaesthesia, the index was maintained at between 40 and 50 during anaesthesia. The cortical SSEP P40-N50 peak-to-peak amplitude and latency time to the P40 peak were measured before induction of anaesthesia, after induction of anaesthesia, at the start of skin incision, at the start of pedicle screw insertion and at the start of rod insertion, by a neurophysiologist blinded to drug allocation. RESULTS: Both propofol and isoflurane decreased SSEP amplitude and increased latency during the course of anaesthesia. After achieving a comparable depth of anaesthesia, the SSEP amplitude was significantly lower with isoflurane, 1.5 (1.0) vs 2.4 (1.4) muV (P=0.005). Latency was significantly longer with isoflurane, 39.5 (3.9) vs 37.3 (3.1) ms (P=0.024). Isoflurane was associated with greater variability of SSEP amplitude during the course of anaesthesia and surgery, coefficient of variation 35.4 (18.0) vs 21.2 (10.2)% (P=0.008). CONCLUSIONS: Propofol anaesthesia caused less suppression of the cortical SSEP, with better preservation of SSEP amplitude, and less variability at an equivalent depth of anaesthesia.

Adolescent↗
PubMed2004

Rates of caesarean section and instrumental vaginal delivery in nulliparous women after low concentration epidural infusions or opioid analgesia: systematic review.

OBJECTIVE: To compare the effects of low concentration epidural infusions of bupivacaine with parenteral opioid analgesia on rates of caesarean section and instrumental vaginal delivery in nulliparous women. DATA SOURCES: Medline, Embase, the Cochrane controlled trials register, and handsearching of the International Journal of Obstetric Anesthesia. STUDY SELECTION: Randomised controlled trials comparing low concentration epidural infusions with parenteral opioids. DATA SYNTHESIS: Seven trials fulfilled the inclusion criteria for meta-analysis. Epidural analgesia does not seem to be associated with an increased risk of caesarean section (odds ratio 1.03, 95% confidence interval 0.71 to 1.48) but may be associated with an increased risk of instrumental vaginal delivery (2.11, 0.95 to 4.65). Epidural analgesia was associated with a longer second stage of labour (weighted mean difference 15.2 minutes, 2.1 to 28.2 minutes). More women randomised to receive epidural analgesia had adequate pain relief, with fewer changing to parenteral opioids than vice versa (odds ratio 0.1, 0.05 to 0.22). CONCLUSIONS: Epidural analgesia using low concentration infusions of bupivacaine is unlikely to increase the risk of caesarean section but may increase the risk of instrumental vaginal delivery. Although women receiving epidural analgesia had a longer second stage of labour, they had better pain relief.

Analgesia, Epidural↗
PubMed2003

The usefulness of routine preoperative chest X-rays and ECGs: a prospective audit.

INTRODUCTION: Pre-operative Chest X-ray (CXR) and electrocardiograms (ECG) are routinely ordered locally for patients above a certain age. This study examines the usefulness of such a practice and its clinical impact. METHODS: Prospective audit of 875 consecutive anaesthetic patients over a one-month period, assessing the proportion and impact of abnormal CXR or ECG findings. RESULTS: The proportion of patients with abnormal CXR or ECG increased with worsening ASA status. There was little impact of routine pre-operative CXR and ECG on anaesthetic management. Only 11/324 CXR and 13/375 ECG affected anaesthetic technique or choice of therapeutic procedure. CONCLUSION: Targeted investigations should be performed as indicated by clinical findings rather than on the basis of arbitrary age cut-offs.

Adult↗
PubMed2002

Nitrous oxide does not improve sevoflurane induction of anesthesia in adults.

STUDY OBJECTIVE: To compare the characteristics of sevoflurane induction with and without the addition of nitrous oxide (N(2)O) using tidal breathing inhalation induction without priming of the breathing circuit. DESIGN: Randomized, double-blind study. SETTING: Operating rooms of an ambulatory surgery suite at a university hospital. PATIENTS: 60 ASA physical status I and II adult patients undergoing elective surgery. INTERVENTIONS: Patients were randomized into two groups. During induction, Group 1 received 8% sevoflurane in N(2)O 4L/min and oxygen (O(2)) 2L/min; Group 2 received 8% sevoflurane in O(2) 6L/min. The time to cessation of finger tapping was used as the main index for induction time. Any adverse effects such as coughing, apnea, excessive oral secretions, laryngospasm, excitatory movements, and hemodynamic changes were also noted. MEASUREMENTS AND MAIN RESULTS: There were no significant differences in the induction times (Group 1: 62.0 vs. Group 2: 60.0 sec), number of breaths taken to this time (15.0 vs. 14.0), expired sevoflurane concentration at this time (3.4 vs. 3.2%), and time to Laryngeal Mask Airway insertion (160.0 vs. 195.0 sec). The frequencies of induction-related adverse events were similar in both study groups. CONCLUSION: The addition of N(2)O does not confer any clinically significant advantage in this method of sevoflurane induction in adults.

Adult↗
PubMed2002

Monitored transtracheal jet ventilation using a triple lumen central venous catheter.

Two patients with nasopharyngeal carcinoma, radiotherapy treatment and 'difficult' airways were anaesthetised for oral surgery. A triple lumen central venous catheter was inserted through the cricoid membrane and transtracheal jet ventilation with an AMS 1000 jet ventilator was performed via the distal lumen. The middle and proximal lumens were connected to an airway pressure monitor and a capnograph, enabling breath-by-breath monitoring of ventilation.

Adult↗