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Biomedical subjects

E H Liu

Publications and source records attributed to E H Liu.

At least 19 recordsLinked to original sources

Ethical issues in living renal donation.

The widespread success of living renal transplantation has given the medical community both the opportunity and the responsibility of establishing social and ethical guidelines for the protection of donors and the treatment of recipients. While the prospects of treating more patients with organ transplant is exciting, the demand still far outpaces the supply. It is the responsibility of the transplant community and individual transplant centers to maintain a high level of integrity and ethical practice so that living renal transplantation can continue to be a viable and effective treatment for renal failure.

Fees and Charges↗

Persistent post-laparoscopy pneumoperitoneum.

BACKGROUND: Persistent pneumoperitoneum after a laparoscopic operation can represent either residual postoperative pneumoperitoneum or free intraperitoneal gas released from the gastrointestinal tract. This animal study was conducted to better characterize the extent and duration of postoperative pneumoperitoneum as detected by computed tomography (CT). METHODS: Five pigs underwent cholecystectomy, four laparoscopically and one open. All pigs were followed serially with upright chest radiographs and abdominal CT scans beginning immediately postoperatively and continuing daily until resolution of pneumoperitoneum as detected by both imaging modalities. All radiographs and CT scans were reviewed by dedicated radiologists who reported the extent and duration of pneumoperitoneum in a blinded fashion. RESULTS: Pneumoperitoneum resolved on upright chest radiographs in all five pigs by or on postoperative day 1. Serial CT scans demonstrated that the laparoscopic group had either resolution of pneumoperitoneum or minimal persistence of free intraperitoneal gas by postoperative day 2. In contrast, the single pig in the open group had CT evidence of persistent pneumoperitoneum through postoperative day 6. CONCLUSIONS: In the pig model, small pockets of free intraperitoneal gas detected by CT scanning are expected to resolve by postoperative day 2 following laparoscopic surgery. Persistence of pneumoperitoneum beyond this interval is abnormal and may represent a perforated viscus. Whereas a prospective CT imaging study in humans is not ethically feasible, we believe that parallel conclusions between the pig and human may be drawn.

Abdominal Pain↗

The isolation and synthesis of novel nematocidal dithiocyanates from an Australian marine sponge, Oceanapia sp.

Bioassay-directed fractionation of the EtOH extract of an Oceanapia sp. collected off the northern Rottnest Shelf, Australia, has yielded three novel dithiocyanates, thiocyanatins A (1), B (2a), and C (2b). The structures were determined by detailed spectroscopic analysis and confirmed by total synthesis. In addition to featuring an unprecedented dithiocyanate functionality, thiocyanatins possess an unusual 1,16-difunctionalized n-hexadecane carbon skeleton and are revealed as a hitherto unknown class of nematocidal agent.

Alkenes↗

Temperature and perfusion responses of muscle and lung tissue during chronic heating in vivo.

For the first time, both temperature and perfusion responses have been obtained from in vivo studies of chronically heated lung and muscle tissue of calves. In each tissue, the spatial temperature distribution was measured by thermistors placed in needles at several distances from an implanted heated disc. A perfusion parameter was defined for a bioheat transfer model that describes temperature dynamics with distance from the heated disc. Estimates of perfusion were obtained by a least-squares fit of the model output to a step change in heat flux. Except for short transient experiments several times a week, a constant heat flux of 0.04, 0.06 or 0.08 Wcm(-2) was maintained at the disc surface for up to seven weeks. At the higher heat fluxes, the steady-state tissue temperature decreased with heating duration. Also, the characteristic time constants of the tissues decreased with heating duration. Muscle perfusion showed a statistically significant increase during chronic heating. Tissue adapts to chronic heating above 42 degrees C by allowing more capillary blood flow that increases heat loss to reduce tissue temperature.

Adaptation, Physiological↗

A clinical report about an unusual occurrence of post-anesthetic tongue swelling.

Dentures are routinely removed from the oral cavity before general anesthetic procedures. They are only reinserted much later when the patient returns to the room. This clinical report describes an edentulous patient who developed acute tongue swelling from venous congestion as a result of tongue recovery from general anesthesia. Her complete dentures were used to separate the residual ridges during the recovery period and relieved the congestion. Denture insertion increased the height and volume of the oral cavity, which reduced pressure on the tongue, preventing a cycle of tongue compression, congestion, and swelling. This unusual complication suggests that it may be prudent for the edentulous patient to be accompanied by their dentures in the perioperative period.

Airway Obstruction↗

Model transformations to evaluate transient thermal responses at a tissue surface.

For a spatially distributed model describing the transient temperature response of a thermistor-tissue system, Wei et al. [J. Biomech. Eng., 117:74-85, 1995] obtained an approximate transformation for fast analysis of the temperature response at the tissue surface. This approximate transformation reduces the model to a single ordinary differential equation. Here, we present an exact transformation that yields a single differential-integral equation. Numerical solutions from the approximate and exact transformations were compared to evaluate the differences with several sets of parameter values. The maximum difference between the exact and approximate solutions did not exceed 15 percent and occurred for only a short time interval. The root-mean-square error of the approximate solution was no more than 5 percent and within the level of experimental noise. Under the experimental conditions used by Wei et al., the approximate transformation is justified for estimating model parameters from transient thermal responses.

Animals↗

A view for patients.

Explore the source record for details and available documents.

Anesthesia, Conduction↗

Patients' perception of sound levels in the surgical suite.

STUDY OBJECTIVES: To measure sound levels that our patients are exposed to in the surgical suite and their perception of these sound levels. DESIGN: Sound levels experienced by 100 patients undergoing general anesthesia for elective surgery during three phases: induction and maintenance of anesthesia in the operating room (OR), and recovery from anesthesia in the recovery room, were measured using a Type 4436 Noise Dose Meter. The equivalent continuous sound levels (Leq), maximum sound levels (Lmax), and the sources of sounds were noted. Patients were interviewed 24 hours after anesthesia about their perception of the sound levels they had experienced in the OR and recovery rooms. MEASUREMENTS AND MAIN RESULTS: The Leq during the induction, maintenance, and recovery phases were 70.3 +/- 16.8 dB(A), 66.2 +/- 4.1 dB(A) and 71.8 +/- 6.1 dB(A), respectively. These sound levels are much higher than international recommendations for hospital acute care areas and exceed the thresholds to produce noise-induced cardiovascular and endocrine effects. Sound levels were significantly higher during the induction and recovery phases compared to the maintenance phase. Thirty-two patients found the induction phase noisy and 33 patients found the recovery phase noisy. The sound levels distressed 16 patients and 52 patients would have preferred a quieter environment. There was no difference in the sound levels experienced by those who expressed dissatisfaction with the sound levels and those who did not. Much of the noise, particularly staff conversations, unnecessary alarms, and preparation of equipment, could have been prevented by simple measures. CONCLUSION: Noise prevention in the OR and recovery room needs more attention and should be a routine part of patient care.

Anesthesia↗

Transplantation of the islets of Langerhans: new hope for treatment of type 1 diabetes mellitus.

For more than two decades, islet transplantation has been pursued as a curative treatment for type 1 diabetes mellitus (T1DM) with little success. It is likely that the failures of the past have involved technical difficulties in harvesting human islets, transplantation of insufficient amounts of islet tissue, the antagonistic effects of immune suppressive drugs, including calcineurin inhibitors and glucocorticoids, graft rejection and recurrent autoimmune disease. More recently, success has been reported in seven out of seven consecutive transplants using approaches that overcome the technical and therapeutic problems of the past. Although this success is noteworthy, issues remain that preclude the general application of islet transplants for treatment of the majority of patients with T1DM. These include the need for chronic immunosuppression and the requirement of large numbers of islets. Efforts are under way, using a variety of immunological, molecular and cellular strategies, to make this promising treatment available to the majority of patients with this disease.

Animals↗

Use of alternative medicine by patients undergoing cardiac surgery.

OBJECTIVE: Complementary and alternative medicine may influence cardiac surgical care by inducing coagulopathies and interacting with perioperative medications. We evaluated the significance of complementary and alternative medicine use in an acutely ill cardiac surgical population and assessed the willingness of patients to reveal these activities to their physicians and surgeons. METHODS: A total of 376 consecutive patients undergoing preoperative or postoperative cardiothoracic surgical evaluations at an urban academic medical center were approached to complete a survey regarding use and attitudes toward complementary and alternative medicine. All surveys were administered and collected between March and May 1998. RESULTS: Completion rate was 70% (n = 263). Respondents were predominantly male (72%), white (76%), and well educated (59%). The overall rate of complementary and alternative medicine use was 75%, but excluding prayer and vitamins, which are often not considered complementary and alternative medicine therapies, the rate was 44%. There was no correlation between the use of complementary and alternative medicine and the parameters of gender, age, race, or education level. Only 17% responded that they had discussed complementary and alternative medicine with their physicians, and 48% responded that they did not want to discuss the topic at all. CONCLUSIONS: Complementary and alternative medicine is used as frequently in patients undergoing cardiac surgery, as in the general population. Physicians and surgeons should be aware that patients have no inherent predisposition toward or against using complementary and alternative medicine, but that they are unlikely to volunteer their experience with it. The unwillingness of patients to discuss complementary and alternative medicine with physicians has serious implications for their safety, especially in acute care situations.

Adult↗

An assessment of the effects on coagulation of midtrimester and final-trimester amniotic fluid on whole blood by Thrombelastograph analysis.

UNLABELLED: The Thrombelastograph((R)) test (TEG; Haemoscope Corporation, Skokie, IL) was used to assess the effects of midtrimester and final-trimester amniotic fluid (AF) on whole blood coagulation. Different volumes of midtrimester and final-trimester AF were added to whole blood from nonpregnant volunteers in a series of TEG tests. The addition of both midtrimester and final-trimester AF resulted in significant decreases in reaction time (P < 0.001) and time from reaction to a fixed level of clot firmness (P < 0.05) and significant increases in angle (P < 0.05) and coagulation index (P < 0.05) values. This reflects accelerated clot initiation and propagation. There was no significant change in the maximal amplitude or % lysis at 30 and 60 min with the addition of either midtrimester or final-trimester AF. There was no significant difference between the effects of midtrimester and final-trimester AF on whole blood TEG. TEG may be an additional useful tool in the treatment of coagulopathy in AF embolism. IMPLICATIONS: We used the Thrombelastograph((R)) test (Haemoscope Corporation, Skokie, IL) to assess the effects of midtrimester and final-trimester amniotic fluid (AF) on whole blood coagulation. Results demonstrate that AF accelerates clot initiation and propagation. The Thrombelastograph((R)) test may be useful in assessing coagulopathy in patients with AF embolism.

Adult↗

Drawover anaesthesia for cleft palate and lip surgery in Pokhara, Nepal.

We describe our experience and problems with 335 children who had general anaesthesia for cleft palate and lip surgery. Drawover anaesthesia using halothane and trichloroethylene was easy to use and safe. The main early postoperative problems were airway obstruction and bleeding. Later postoperative care in the ward was hampered by the lack of nursing care and monitoring.

Airway Obstruction↗

Sevoflurane anaesthesia with the Komesaroff vaporizer inside the circle system.

This study assessed the safety of sevoflurane anaesthesia using two Komesaroff vaporizers inside the circle with both spontaneous and controlled ventilation. Sevoflurane concentrations were continuously monitored using a mass spectrometer and the anaesthetic depth was easily controlled. Involuntary movements occurred in eight patients and breath-holding occurred in five patients after inhalational induction. With continuous monitoring of sevoflurane concentrations, induction and maintenance of anaesthesia using a vaporizer inside the circle is safe during both controlled and spontaneous ventilation. However the high incidence of involuntary movements may limit the feasibility of induction in spontaneously breathing patients.

Adult↗

Sevoflurane output from the Oxford Miniature Vaporizer in drawover mode.

The sevoflurane output from the Oxford Miniature Vaporizer (OMV) was measured in a series of bench tests in a drawover system. Using a range of settings on two OMVs in series, output ranged from 0.5 to 5.9% with a 600 ml tidal volume at a rate of 12 breaths/min produced by a Penlon Multivent. The OMVs' output was steady over 40 minutes. In tests with tidal volumes ranging from 300 ml to 1200 ml, the OMVs' output was lower at higher minute volumes. When continuous flow of carrier gas at 7.2 l/min was used, the output was lower than at the equivalent intermittent flow rate. Using two OMVs with a drawover system appears to be a feasible technique for the induction and maintenance of sevoflurane anaesthesia. Clinical tests of sevoflurane drawover anaesthesia are now required so that the advantages of sevoflurane can gain wider application in field and military anaesthesia.

Anesthesiology↗

Perioperative wheezing--a report of three cases.

CLINICAL PICTURE: We describe 3 patients with perioperative wheezing, 2 of whom were treated with bronchodilators on the presumptive diagnosis of bronchospasm. TREATMENT AND OUTCOME: Subsequent clinical improvement occurred when it was recognised that the wheezing was due to upper airway obstruction and stridor, not bronchospasm and rhonchi, and appropriate treatment instituted.

Aged↗