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Problems in projectile motion are a time-honored staple of high school and even first-year university physics. They can become confusing for some students, yet boring for the stronger students. Herein we present two alternative approaches to such questions, one we call “breaking down gravity,” which makes these questions easier to solve, and the other we call “getting rid of gravity,” which converts such questions into a more interesting and challenging form.

The prototypes of two novel warning devices for protection against dental trauma during direct laryngoscopy are described. Either can be attached to a standard laryngoscope blade (e.g., Macintosh). The basic design is that of as witch that is closed by pressure on the maxillary incisors by the laryngoscope blade.

Ba6Ni25S27, synthesized by solid-state reaction of BaS, NiS, and Ni at 675°C, is cubic (Pm3m, a = 10.057(1) A). The structure was refined by using powder X-ray diffraction and Rietveld methods with Rp = 6.28%, Rwp = 8.13%, χ2 = 3.120. The structure, isotypic with Ba6Co25S27, consists of an extended network of Ni8S14 pseudo-cube clusters, NiS6 octahedra, and Ba6S octahedra. Extended Huckel calculations of this compound indicate the band structure near the Fermi level to be composed mostly of d-character orbitals of tetrahedral Ni, and reveal a peak in the density of states slightly below the Fermi level. The temperature dependence of the electrical resistivity exhibits a local maximum with thermal hysteresis at around 230 K. Above and below this transition, the slope of the resistivity is positive, with a room-temperature resistivity (ρ = 0.23 mωcm) in the range for that of a poor metal conductor. Magnetic susceptibility measurements from 4 to 900 K indicate a sharp change in slope at around 225 K, with a steadily increasing susceptibility up to 900 K. The susceptibility below 225 K suggests Pauli paramagnetic behavior. Low-temperature powder X-ray diffraction and subsequent structure refinement shows that the lattice parameter, a, undergoes a slight change in slope at temperatures of around 235 K.

A matrix method for the detection of static hazards in combinational logic circuits has been reported (Heal and Page 1993). The method generates 0 and 1-sets of all nodes in each gate level of a circuit progressively until it reaches the output of the circuit. The sets generated are subsequently used to determine the existence of static hazards. This paper introduces enhancements to improve the capabilities and performances of the method, which is applicable to the detection of logic hazards in synchronous combinational logic circuits only. It is shown how certain matrix operations can be simplified to save storage and computation time. A simpler way of determining static hazards is proposed. Required modifications of the method to incorporate the detection of dynamic hazards are presented. It is further shown that the algorithm can also be applied to the transient analysis of digital circuits with exclusive-OR (EX-OR) gates. Examples are given for illustration.

Reconstructions of the chest wall using commercially available artificial metallic rib systems are gaining in popularity. The MatrixRib system involves use of plates and screws to bridge any defect and provide support for the chest wall following resection. So far, there has been no publication focusing on describing the use of this new technology in a step-by-step approach. We describe our technique and discuss potential pitfalls and difficulties of using the system.

In recent years, a novel approach using the Djumbodis dissection system aortic stent has been introduced as an alternative to aortic arch replacement in acute type A aortic dissection involving the arch. From 2010 to 2013, we treated 7 patients with acute type A aortic dissection using the technique of replacing the ascending aorta with interposition graft and stenting of the aortic arch with the Djumbodis dissection system. We followed up the patients with serial imaging and in 3 consecutive patients who had been followed up for more than 10 months, we noted significant deformity and fracture of the Djumbodis stent.

During double-lumen tube (DLT) placement, the anesthesiologist must be mindful of the margin of safety. We determined how this margin is affected by the presence of a tracheal bronchus by elucidating the mathematical relationship between some relevant physical dimensions of the trachea, bronchi, and DLT. Our results suggest that a tracheal bronchus only rarely affects the intrinsic margin of safety of DLT placement. When the tracheal bronchus is located much higher than its most frequently seen location (within 2 cm from the carina), however, there is increased risk that it could be blocked by the tracheal cuff of a left-sided DLT.

This paper opens with an overview of the debatable definition of soft soil that goes beyond a (CH) organic / inorganic clay and OH peat to include weakly cemented periglacial deposits of loess and alike. It then outlines the findings obtained from stiffness test on cement-stabilised soft clay. The findings are complemented with a microstructure viewpoint obtained using field emission scanning electron microscope (FESEM). Research also comprised of making cylindrical stabilised clay samples, prepared in the laboratory with various rubber chips contents and cement, and then aged for 28 days. The samples were then subjected to unconfined compressive strength (UCS) test and observations were also made of its microstructure using the FESEM. The impact of the soil microstructure on the stiffness result was studied both with the stabilized soil and also of some of the natural undisturbed loess soils. Sustainability aspect and the potential of the use of rubber chips and sand as additives to cement stabilisation are also discussed. The overall test results indicated that rubber chips and sand contributed to the improvement in unconfined compressive strength (qu). The derogatory influence of moisture on the stiffness of the stabilised clay was studied simultaneously. SEM micrographs are presented that show bonding of cement, rubber chips/ sand and soft clay, granular units and aggregated / agglomerated units in loess. The paper concludes with observations on the dependence of soil microstructure on the soil strength and deformability and even collapsibility of the loess. Current practices adopted as engineering solutions to these challenging soils are outlined.

Background Observational studies on injured patients requiring massive transfusion have found a survival advantage associated with use of equivalent number of units of fresh frozen plasma (FFP) and packed red blood cells (RBCs) compared with use of FFP based on conventional guidelines. However, a survivorship bias might have favoured the higher use of FFP because patients who died early never had the chance to receive sufficient FFP to match the number of RBC units transfused. Methods A Markov model using trauma data from local hospitals was constructed and various FFP transfusion scenarios were applied in Monte Carlo simulations in which the relative risk of death associated with exposure to high FFP transfusion was set at 1·00, so that the FFP : RBC ratio had no influence on mortality outcome. Results Simulation results showed that the relative risk associated with exposure to high FFP transfusion was less than 1·00 (0·33–0·56 based on programmed delays in achieving an FFP : RBC ratio of 1 : 1–2), thus demonstrating a survivorship bias in favour of FFP : RBC equal to or more than 1 : 1–2 in certain observational trauma studies. This bias was directly proportional to the delay in achieving a FFP : RBC ratio of 1 : 1–2 during resuscitation. Conclusion Some observational studies comparing low and high FFP administration in injured patients requiring massive transfusion probably involve survivorship bias that inflates or creates a survival advantage in favour of a higher FFP : RBC ratio.

The purpose of this study was to explore the complex flow structure a novel active-type micromixer that based on concept of Wankle-type rotor. The characteristics of this micromixer are two folds; a rapid mixing of reagents in a limited space due to the generation of multiple vortices and a graduate increment in dynamic pressure as the mixed reagents is delivered to the output ports. Present micro-mixer is consisted of a rotor with shape of triangle column, a blending chamber and several inlet and outlet ports. The geometry of blending chamber is designed to make the rotor can be freely internal rotated with a constant eccentricity ratio. When the shape of the blending chamber and the rotor are fixed, the effects of rotating speed of rotor and the relative locations of ports on the mixing efficiency are numerical studied. The governing equations are unsteady, two-dimensional incompressible Navier-Stokes equation and the working fluid is the water. The species concentration equation is also solved to reveal the mass transfer process of reagents in various regions then to evaluate the mixing efficiency. The dynamic mesh technique was implemented to model the dynamic volume shrinkage and expansion of three individual sub-regions of blending chamber when the rotor conducted a complete rotating cycle. Six types of ports configuration on the mixing efficiency are considered in a range of Reynolds number from 10 to 300. The rapid mixing process was accomplished with the multiple vortex structures within a tiny space due to the equilibrium of shear force, viscous force and inertial force. Results showed that the highest mixing efficiency could be attained in the following conditions: two inlet and two outlet ports configuration, that is an included angle of 60 degrees between two inlets and an included angle of 120 degrees between inlet and outlet ports when Re=10.

Objectives: The use of ultrasound to guide peripheral nerve blocks is now a wellestablished technique in regional anaesthesia. However, despite reports of ultrasound guided epidural access via the paramedian approach, there are limited data on the use of ultrasound for central neuraxial blocks, which may be due to a poor understanding of spinal sonoanatomy. The aim of this study was to define the sonoanatomy of the lumbar spine relevant for central neuraxial blocks via the paramedian approach. Methods: The sonoanatomy of the lumbar spine relevant for central neuraxial blocks via the paramedian approach was defined using a ‘‘water-based spine phantom’’, young volunteers and anatomical slices rendered from the Visible Human Project data set. Results: The water-based spine phantom was a simple model to study the sonoanatomy of the osseous elements of the lumbar spine. Each osseous element of the lumbar spine, in the spine phantom, produced a ‘‘signature pattern’’ on the paramedian sagittal scans, which was comparable to its sonographic appearance in vivo. In the volunteers, despite the narrow acoustic window, the ultrasound visibility of the neuraxial structures at the L3/L4 and L4/L5 lumbar intervertebral spaces was good, and we were able to delineate the sonoanatomy relevant for ultrasound-guided central neuraxial blocks via the paramedian approach. Conclusion: Using a simple water-based spine phantom, volunteer scans and anatomical slices from the Visible Human Project (cadaver) we have described the sonoanatomy relevant for ultrasound-guided central neuraxial blocks via the paramedian approach in the lumbar region.

Many cities have established Web-based road hazard report/notification systems to improve citizeni¦s driving safety and comfort. However, some of the systems are not very user-friendly. On the other hand, a driver sometimes does not know his/her vehicle already has some problems, but the malfunctioning vehicle is still driven on the road. Under this condition, the driver and other road users are all not very safe. This paper proposes a DSRC vehicular warning and notification system. The proposed system consists of multiple communication interfaces to provide real-time traffic warning and rapid notification of traffic information. It is capable of detecting road hazards and transmitting traffic information to the Internet through intervehicular communications via DSRC. In addition, the vehicular status self-check data can be acquired through Control Area Network (CAN) bus. With Web Services, the proposed system could report traffic information to city traffic centers for informing other road users, or car maintenance factories for car fault rescue. A prototype system was implemented, and the road test results show the proposed system can be used not only to enhance driving safety but also to simplify the notification of road problems.

We read with interest the article by Morrison et al. [1] about military ballistic thoracoabdominal injuries from a British Military Hospital in Afghanistan. In their series of 27 patients, many required surgical exploration either at presentation or after further investigation with CT. The study prompted us to review retrospectively our experience during a similar period. The medical records and CT scans of 21 soldiers transferred from Afghanistan military field hospitals to The Royal Centre for Defense Medicine Selly Oak Hospital and Queen Elizabeth Hospital, Birmingham, United Kingdom, between July 2006 and October 2008 for thoracic injuries were examined. The mean age of the soldiers was 29 years (standard deviation (SD), 2.7), and 11 (52%) were intubated upon arrival with a further 4 subsequently requiring intubation. Three intubated soldiers were related to presence of flail chest from trauma. Sixteen soldiers suffered from blast injuries and three from bullet injuries (only one penetrated the intrathoracic cavity). Eleven had pneumothoraces that required intercostal drainage. Seven patients had shrapnel injuries (Fig. 1), and five patients had formal chest wall wound debridement. None required surgical intervention to the lungs. One patient required sternotomy for intramyocardial shrapnel removal in nonemergent setting (Fig. 2). The mean (±SD) Injury Severity Scale Score for the patients was 6 (±5). Conservative management was adopted for the remaining cases. Mean hospital stay was 32 days, and there was no mortality at 9 months follow-up. As expected, there is a clear contrast in the severity of injuries and management strategies between soldiers treated at military field hospital and those stable enough to be transferred back to United Kingdom. Interestingly, thoracotomy was not required for any of our patients, whereas it was performed and therapeutic in select cases at the frontline hospital. Previous series on military injury reported emergency thoracotomy was necessary in 12–15% of cases of thoracic trauma, indicated usually in those with cardiovascular collapse from uncontrolled intrathoracic hemorrhage [2]. It is well accepted that those patients with penetrating injury arriving to medical centers with signs of life or those who had prehospital time of less than or equal to 30 min do best in emergency thoracotomies [2, 3]. Furthermore, the procedure is almost universally unsuccessful in patients of class 1 (no signs of life) or class 2 (agonal; with pulseless electrical activity) in advanced trauma life support/early management of severe trauma (ATLS/EMST) terms [2]. The cohort of patients who arrived at our centre clearly fell outside of these categories, having already had initial assessment and appropriate emergency resuscitation at field hospitals. Our patient group, similar to that described by Rosenblatt et al. [2] consisted of those who initially survived the thoracic injury after primary treatment—surgical or conservative—and were successfully transferred to specialist trauma C. S. H. Ng (&) M. J. Underwood Department of Cardiothoracic Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong SAR, China e-mail: calvinng@surgery.cuhk.edu.hk

Surgical emphysema is a well-recognised complication of laparoscopic surgery, but its impact on end-tidal carbon dioxide levels and carbon dioxide elimination is seldom reported and may not be fully appreciated by anaesthetists. Four cases are presented where extensive surgical emphysema occurred during laparoscopic surgery. The visual display of the anaesthetic record using the software program Monitor showed substantial rises in end-tidal carbon dioxide levels and allowed calculation of the carbon dioxide elimination, which increased two- to three-fold above normal levels. Having a visual record of carbon dioxide changes facilitated the recognition of surgical emphysema in three out of the four cases. Strategies such as estimating and tracking changes in carbon dioxide elimination from the minute ventilation and end-tidal carbon dioxide levels may assist in early identification, and palpating for surgical emphysema is recommended during laparoscopy if other causes of increased carbon dioxide levels are excluded.

A case is presented in which memory of events during emergence from anaesthesia resulted in serious psychological sequelae. Communication with patients should begin almost immediately after anaesthesia has been terminated and should have prevented this unfortunate incident.

Cricoid pressure, when properly applied, may prevent gastric regurgitation and may improve the view of laryngoscopy. When improperly applied, however, it can impede laryngoscopy and mask-ventilation. When faced with a “cannot intubate” or “cannot mask-ventilate” situation, clinicians should reevaluate the manner with which the assistant is applying cricoid pressure and must be prepared to adjust or even to release it.

As fabrication process technology continues to advance, mask set costs have become prohibitively expensive. Structured ASICs can offer price and performance between ASICs and FPGAs. They are attractive for mid-volume production and offer good intellectual property security. In this paper, a structured ASIC methodology, where 2 metal- and 1 via-mask are customised, is described. The CAD tools are fully compatible with conventional ASIC design flows and a comparison of area and delay performance with ASICs and FPGAs is given. A prototype structured ASIC implementing an LED-backlit LCD controller was fabricated in a 0.13µm CMOS process. It was verified and power consumption compared with an ASIC design.

Ba6Ni25S27, synthesized by solid-state reaction of BaS, NiS, and Ni at 675°C, is cubic (Pm3m, a = 10.057(1) A). The structure was refined by using powder X-ray diffraction and Rietveld methods with Rp = 6.28%, Rwp = 8.13%, χ2 = 3.120. The structure, isotypic with Ba6Co25S27, consists of an extended network of Ni8S14 pseudo-cube clusters, NiS6 octahedra, and Ba6S octahedra. Extended Huckel calculations of this compound indicate the band structure near the Fermi level to be composed mostly of d-character orbitals of tetrahedral Ni, and reveal a peak in the density of states slightly below the Fermi level. The temperature dependence of the electrical resistivity exhibits a local maximum with thermal hysteresis at around 230 K. Above and below this transition, the slope of the resistivity is positive, with a room-temperature resistivity (ρ = 0.23 mωcm) in the range for that of a poor metal conductor. Magnetic susceptibility measurements from 4 to 900 K indicate a sharp change in slope at around 225 K, with a steadily increasing susceptibility up to 900 K. The susceptibility below 225 K suggests Pauli paramagnetic behavior. Low-temperature powder X-ray diffraction and subsequent structure refinement shows that the lattice parameter, a, undergoes a slight change in slope at temperatures of around 235 K.

Background There is limited evidence to guide the recognition of patients with massive, uncontrolled hemorrhage who require initiation of a massive transfusion (MT) protocol. Objective To risk stratify patients with major trauma and to predict need for MT. Designs Retrospective analysis of an administrative trauma database of major trauma patients. A regional trauma Centre A regional trauma centres in Hong Kong. Patients Patients with Injury Severity Score ≥9 and age ≥12 years were included. Burn patients, patients with known severe anemia and renal failure, or died within 24 h were excluded. Main outcome measures Delivery of ≥10 units of packed red blood cells (RBC) within 24 h. Results Between 01/01/2001 and 30/06/2009, 1891 patients met the inclusion criteria. 92 patients required ≥10 units RBC within 24 h. Seven variables which were easy to be measured in the ED and significantly predicted the need for MT are heart rate ≥120/min; systolic blood pressure ≤90 mmHg; Glasgow coma scale ≤8; displaced pelvic fracture; CT scan or FAST positive for fluid; base deficit >5 mmol/L; hemoglobin ≤7 g/dL; and hemoglobin 7.1–10 g/dL. At a cut off of ≥6, the overall correct classification for predicting need for MT was 96.9%, with a sensitivity of 31.5% and specificity of 99.7%, and an incidence of MT of 82.9%. The area under the curve was 0.889. Conclusion A prediction rule for determining an increased likelihood for the need for massive transfusion has been derived. This needs validation in an independent data set.

A Structured Application-specific Integrated Circuit (SASIC) is a programmable fabric in which a small set of masks are customized for a particular application, serving to reduce the associated non-recurring engineering cost (NRE). In this paper we describe the implementation of a SASIC logic cell which is programmable via a single metal layer. A SASIC fabric prototype is fabricated and all implemented functions are verified on silicon. Experimental measurement verifies correct operation of our SASIC with a clock frequency of over 250MHz.

A comparison of ultra-wideband (UWB) communication characteristics for six different geometrical shapes is investigated. These six shapes include the straight shape corridor with rectangular cross section, the straight shape corridor with arched cross section, the curved shape corridor with rectangular cross section, the curved shape corridor with arched cross section, the L-shape corridor, and the T-shape corridor. The impulse responses of these corridors are computed by applying shooting and bouncing ray/image (SBR/Image) techniques and inverse Fourier transform. The frequency dependence utilized in the structure on the indoor channel is accounted for in the channel calculation. By using the impulse response of these multi-path channels, the mean excess delay, root mean square (RMS) delay spread, number of dominate paths (85% energy), and number of significant paths (within 10d B peak) for these six corridors could be obtained. Numerical results show that the RMS delay spreads for the arched cro...

Synthetic Floating-Point (SFP), a synthetic benchmark generator program for floating-point circuits is presented. SFP consists of two independent modules for characterisation and generation. The characterisation module extracts key dataflow statistics of an arbitrary software program. Generation involves producing randomised circuits with desired statistics which are either the output of the characterisation module or directly generated by the user. Using the basic linear algebra subprograms (BLAS) library, Whetstone benchmark and LINPACK benchmark, it is demonstrated that SFP can be used to generate floating-point benchmarks with different user-specified properties as well as benchmarks that mimic real computational programs.

To evaluate the incidence of deep venous thrombosis in critically ill, Intensive Care Unit patients of Chinese ethnicity.Prospective, observational study.Intensive Care Unit in a Hong Kong teaching hospital.Consecutive adult Chinese medical patients not receiving pharmacological or mechanical prophylaxis for deep venous thrombosis.Compression and duplex Doppler ultrasound examinations of the lower limbs within 24 hours of admission and twice weekly thereafter during their Intensive Care Unit stay. After discharge, a 1-week follow-up investigation was also performed. Demographic data and risk factors for deep venous thrombosis were prospectively recorded.Over a 9-month study period, 80 patients were investigated. Deep venous thrombosis was detected by ultrasound examination in 15 (19%) of the patients (95% confidence interval, 14-23%). Nine of 15 had isolated below-knee deep venous thrombosis, and of these, five had bilateral involvement. Characteristics of patients with or without deep venous thrombosis were similar. Of the 15 patients who had a positive ultrasound examination, only four (27%) had clinical signs of deep venous thrombosis. Of the 65 patients without a positive ultrasound examination, only two (3%) had positive clinical signs (P=0.01). This yielded a moderate positive likelihood ratio of 9 (95% confidence interval, 2-43) and a small negative likelihood ratio of 0.76 (95% confidence interval, 0.56-1.03). There were no cases of pulmonary embolism. Hospital mortality in those with and without deep venous thrombosis was 33% and 28%, respectively.In the absence of prophylaxis, the incidence of deep venous thrombosis in Chinese medical Intensive Care Unit patients is lower than that reported in similar Caucasian patients, but higher than expected. As clinical features are not able to reliably exclude the presence of deep venous thrombosis, early routine prophylaxis for deep venous thrombosis in Chinese medical Intensive Care Unit patients should be considered.

We present nine cases of one-lung anaesthesia in small children and infants in which a novel technique was used to reduce the risk of endobronchial blocker retrograde dislodgement. The technique involved threading the stem of the blocker through the Murphy eye of the endotracheal tube (ETT) and deliberately passing the tip of the ETT all the way to the carina. The tip of the ETT blocked any retrograde movement of the blocker.

Airway, breathing, and circulation are top priorities in any resuscitation. However, in cardiac tamponade, the decision to intubate the trachea and initiate positive pressure ventilation (PPV) should only be taken after consideration of the deleterious haemodynamic effects of positive intrathoracic pressure. We suggest that the threshold for intubation and PPV should be raised in tamponade and that intubation and PPV should, if possible, be timed so that relief of tamponade can immediately follow. In the trauma setting, emergency thoracotomy is the best approach. When intubation is unavoidable because of very low oxygen saturation or cardiac arrest, high ventilatory pressures should be avoided.

Intraabdominal hypertension reduces organ blood flow. Restoring abdominal perfusion pressure (APP) may restore renal blood flow, especially when sepsis is present. The effects of intra-abdominal pressure (IAP), followed by restoration of APP with norepinephrine, on renal blood flow were determined.Longitudinal study with bacteremia after nonbacteremic (control) conditions.University animal laboratory.Ten anesthetized mongrel dogs.IAP was raised to 10, 20, and 30 mm Hg, using intra-abdominal bags filled with saline. After each intervention, decompression was achieved by emptying the bag. Bacteremia was induced by injection of Escherichia coli. Cardiac output and renal blood flow were measured using surgically placed flow probes. Norepinephrine infusion was used to restore the mean arterial pressure to baseline at each IAP. A hypervolemic circulation was maintained throughout by infusing saline.Induction of bacteremia resulted in significant decreases in blood pressure, cardiac output, and renal blood flow (p.01). Serial increases in IAP decreased cardiac output and renal blood flow both in control and bacteremic dogs (p.001). These decreases were substantially corrected by abdominal decompression. In nonbacteremic control conditions, restoring APP back to baseline with norepinephrine did not fully restore cardiac output and renal blood flow (p.001). However, in bacteremic conditions, norepinephrine was able to substantially restore cardiac output and renal blood flow to bacteremic baseline at all levels of IAP. In bacteremic conditions, the renal perfusion fraction returned to bacteremic baseline levels after correction of APP with norepinephrine and after decompression.Restoration of APP using norepinephrine improves renal blood flow in bacteremic animals with IAPs up to 30 mm Hg, and maintaining a therapeutic APP may preserve renal blood flow in patients with intra-abdominal hypertension who are at risk of IAP-induced renal injury but who have yet to meet accepted criteria for surgical decompression.

Aims: To perform an economic analysis of government-funded universal rotavirus vaccination in Hong Kong from the government’s perspective. Methods: A Markov model of costs and effects (disability averted) associated with universal vaccination was compared with no vaccination. In both strategies, newborns were studied until 5 years of age or until they died, using cost, probability and utility data from the literature. The potential cost savings and cost effectiveness of vaccination were calculated and their sensitivities to changes in vaccine and health care costs, presumed decline in vaccine efficacy over time, and the use of discounting and age weights were determined. Results: Depending on assumptions, the new rotavirus vaccines would be cost saving to the Hong Kong Government if they cost less than US$40–92 per course. Higher vaccine costs would quickly lead to an incremental cost-effectiveness ratio exceeding that of the gross national product per capita if the mortality rate of rotavirus gastroenteritis remained at zero. Conclusions: Based on 2002 demographic, cost and morbidity data and reasonable uncertainty estimates of these variables, a universal rotavirus vaccination programme paid for by the Hong Kong Government is cost neutral at a per course vaccine cost of US$40–92. For a fixed vaccine cost, the potential savings and cost effectiveness of the vaccine increase with higher estimated health care costs and vice versa.

Epidural analgesia improves postoperative outcome, and should benefit patients undergoing hepatectomy for cancer. However, the combination of underlying disease, surgery, and blood loss after hepatectomy may lead to hemostatic changes that, theoretically, increase the risk of epidural hematoma. To quantify these changes, we retrospectively reviewed the records of 229 patients at the Prince of Wales Hospital, Hong Kong.We analyzed the hemostatic parameters of those in whom there were complete data (n=143) up to postoperative day 3.We found considerable derangements in the international normalized ratio (INR), prothrombin time, activated partial thromboplastin time (aPTT), and platelet counts, with peak derangements occurring around postoperative day 2. The amount of liver resected and the preoperative Model for End-Stage Liver Disease score were predictors of peak INRor = 1.5 in the postoperative period.We conclude that commonly measured hemostatic parameters are deranged after hepatectomy for cancer. Because of the complex cancer- and surgery-related hemostatic changes, whether these changes indeed indicate increased risk of neuraxial hematoma associated with neuraxial blocks is unclear. We also found that most Chinese patients were managed adequately with patient-controlled intravenous morphine. Clinicians contemplating neuraxial block on patients undergoing hepatectomy for cancer must weigh the potential risks and benefits.

Background: Open tracheostomy is commonly performed during head and neck surgery, and in critically ill patients. Diathermy-induced airway fire during tracheotomy is rare but may have grave implications. Recommendations to minimize this risk are not always practical. We hypothesized that flooding the surgical field with carbon dioxide is an effective technique in preventing fire. Methods: We cut through the trachea of two pigs using diathermy while ventilating with pure oxygen five times with, and five times without, simultaneous flushing of the surgical field with carbon dioxide at 10 L/min. To increase the amount of oxygen in the airway and the likelihood of fire,we deliberately deflated the endotracheal cuff to simulate cuff rupture. Results: Five times out of five, fire was induced when the diathermy cut through the tracheal wall with no carbon dioxide being used. Five times out of five, fire was not induced when carbon dioxide was used. The difference was significant (p < 0.008). Conclusions: Flooding the surgical site with carbon dioxide effectively prevents fire during open tracheostomy using diathermy.

Perioperative hypoxaemia is a common but serious problem with well recognised causes. However, an anomalous bronchus causing lobar collapse as a cause is seldom mentioned. A healthy young male patient was anaesthetised for a knee operation. He required reintubation immediately postoperatively for hypoxia. He was found to have right upper lobe collapse. Fibreoptic examination of the trachea demonstrated an anomalous bronchus as the cause. Intra-operatively, the endotracheal tube had been inserted too deeply and the bronchial orifice had been obstructed by the tip. It took several hours for the lung to re-expand. Greater awareness of this potential complication is needed.

To describe a novel airway management technique for thoracoscopic repair of a type C tracheoesophageal fistula (TEF) in a neonate.A full-term neonate with a type C TEF presented for thoracoscopic repair. The fistula was at the level of the carina, making its isolation from positive pressure ventilation using traditional techniques difficult. In addition, non-ventilation of the right lung was required. The use of two Fogarty type balloon-tipped embolectomy catheters placed alongside the endotracheal tube successfully achieved the goal of blocking ventilation of the fistula and the right lung. The use of fibreoptic bronchoscopy greatly facilitated placement of the blockers. The patient made an uneventful recovery.Placing two balloon-tipped blockers, one in the TEF and the other in the right mainstem bronchus, is a viable technique for thoracoscopic fistula repair when the fistula is at or very close to the level of the carina.

We use the stroboscopic effect to explain how a moving object seen on television can appear to be moving in an opposite direction and/or at velocities different from its true velocities.

To provide an update on cutaneous tuberculosis in Hong Kong.Retrospective study.Social Hygiene Service (Dermatology Division), the largest dermatological referral centre in Hong Kong.Patients presented with cutaneous tuberculosis between 1993 and 2002 inclusive. Case notes, histology reports, and microbiological reports were reviewed with particular reference to the epidemiology, duration of illness, history of contact with tuberculosis, culture results, and response to treatment.There were 147 patients with cutaneous tuberculosis; among these a few had true cutaneous tuberculosis (n = 16) and the remainder were tuberculids (n = 131). In all they accounted for 0.04% of new dermatology cases diagnosed. Cases of cutaneous tuberculosis were distributed as follows: lupus vulgaris (n = 6, 4%), tuberculosis verrucosa cutis (n = 6, 4%), tuberculosis of the skin unclassified (n = 2, 1%), and orificial tuberculosis (n = 2, 1%). Culture and polymerase chain reaction was positive in less than half of the latter cases. All responded well to anti-tuberculosis therapy. Erythema induratum was the most common form (n = 127, 86%), but papulonecrotic tuberculids (n = 4, 3%) were uncommon. Erythema induratum affected the lower limb in all patients, with a female predominance, and responded to isoniazid monotherapy, multidrug anti-tuberculosis therapy, or doxycycline.Lupus vulgaris and tuberculosis verrucosa cutis remain the commonest forms of true cutaneous tuberculosis, and erythema induratum is the most common tuberculid. Culture and polymerase chain reaction are positive in a small proportion of patients.

To review the epidemiology of atypical mycobacterial cutaneous infection in Hong Kong.Retrospective study.Social Hygiene Service (Dermatology Division), the largest dermatological referral centre in Hong Kong.Patients with a diagnosis of atypical mycobacterial cutaneous infection based on clinical features, histopathology, with or without a positive culture during the period 1993 to 2002.Epidemiological data, clinical features, histology, microbiological investigation, and treatment response.Of 345,394 dermatological cases presented over the 10-year period, 33 (0.0096%) cases (19 male, 14 female) of atypical mycobacterial cutaneous infection were diagnosed. The most common type of infection was caused by Mycobacterium marinum (n=17, 51.5%), followed by Mycobacterium avium-intracellulare (n=3, 9.1%) and Mycobacterium chelonae (n=2, 6.1%). The upper limb, especially the hands and fingers, was the most common (69.7%) site of involvement. Tissue culture was positive in 18 (54.5%) cases. All biopsies showed granulomatous histology. Thirty-two patients received treatment and 31 responded. Twenty-six were treated with oral tetracycline group of antibiotics (minocycline, doxycycline, tetracycline). The duration of treatment ranged from 8 to 54 weeks (mean, 24 weeks). Mild transient adverse effects to treatment were reported in six cases.Atypical mycobacterial infection is rare in Hong Kong. Because of the low sensitivity of traditional culture techniques, atypical mycobacterial infection may be underdiagnosed if only culture-confirmed cases are included. Polymerase chain reaction provides a rapid and sensitive method to improve diagnostic accuracy. Tissue culture is crucial to determine antimicrobial susceptibility. In our study, tetracycline group of antibiotics, especially minocycline, was an effective treatment, particularly in cases caused by Mycobacterium marinum.

Randomized controlled trials of how best to administer fresh frozen plasma (FFP) in the presence of ongoing severe traumatic hemorrhage are difficult to execute and have not been published. Meanwhile, coagulopathy remains a common occurrence during major trauma resuscitation and hemorrhage remains a major cause of traumatic deaths, suggesting that current coagulation factor replacement practices may be inadequate.We used a pharmacokinetic model to simulate the dilutional component of coagulopathy during hemorrhage and compared different FFP transfusion strategies for the prevention or correction, or both, of dilutional coagulopathy. Assuming the rates of volume replacement and loss are roughly equal, we derived the hematocrit and plasma coagulation factor concentration over time based on the rate of blood loss and replacement, the hematocrit and coagulation factor concentration of the transfusate, and the hematocrit and plasma factor concentration at the time when FFP transfusion begins.Once excessive deficiency of factors has developed and bleeding is unabated, 1-1.5 units of FFP must be given for every unit of packed red blood cells (PRBC) transfused. If FFP transfusion should start before plasma factor concentration drops below 50% of normal, an FFP:PRBC transfusion ratio of 1:1 would prevent further dilution.During resuscitation of a patient who has undergone major trauma, the equivalent of whole-blood transfusion is required to correct or prevent dilutional coagulopathy.

To investigate the antioxidant and anti-endotoxin effects of propofol on endothelial cells and the possible mechanisms.Cultured endothelial cells were treated with hydrogen peroxide (H(2)O(2)), propofol + H(2)O(2), lipopolysaccharide (LPS) and propofol + LPS, respectively. Endothelial cell damage was monitored for possible lactic dehydrogenase (LDH) release. The transcription and the protein expression levels of endothelial nitric oxide synthase (eNOS) were measured.LDH release was higher in groups treated with H(2)O(2) or LPS than in the control group. After pretreatment with propofol, the effects induced by H(2)O(2) were attenuated, but propofol did not decrease the LDH release induced by LPS. Both H(2)O(2) and LPS significantly increased the eNOS transcript levels and the increases were significantly attenuated after pretreatment with propofol. Both H(2)O(2) and LPS significantly increased the eNOS protein expression and the increase was attenuated after pretreatment with propofol.Propofol could protect endothelial cells against oxidative stress by inhibiting eNOS transcription and protein expression, but could not antagonise endotoxin induced cell injuries.

Prompted by an actual case of potentially life-threatening infusion pump malfunction, we investigated the effects of wire breakage(s) within the syringe size sensor circuit in a Graseby 3400 infusion pump.The circuit wires within the sensor were systematically broken.The syringe sizes recognised by the sabotaged circuit and the actual sizes of syringes inserted into the pump were compared.Thirty-eight per cent of the possible wire breakages resulted in a smaller syringe size being recognized, causing the infusion rate to be too fast, and 38% of the possible wire breakage resulted in a larger syringe size being recognized, causing the infusion rate to be too slow.The volume delivered for each different size of Terumo syringe as a function of distance travelled by the plunger was measured.The errors ranged from 0.4 to 2.6 times that of the expected rate.Only 1.3% of the possible wire breakage(s) were recognised as errors by the pump.The infusion rates were not affected in 22.5% of the cases.Wire breakage within the syringe size sensor in infusion pumps is yet another potential source of infusion error, with important safety implications.