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Biomedical subjects

H P Lau

Publications and source records attributed to H P Lau.

At least 19 recordsLinked to original sources
PubMed2001

Delayed airway obstruction secondary to inadvertent arterial puncture during percutaneous central venous cannulation.

We report a case of fatal respiratory complication secondary to central venous cannulation in a 63-year-old male patient, which came up gradually and insidiously following an accidental puncture of carotid artery in an attempt to cannulate the right internal jugular vein. He died 14 h after the mishap due to severe upper airway obstruction. The nature of the vascular laceration was still obscure.

Airway Obstruction↗
PubMed1998

Regional nerve block for total knee arthroplasty.

Femoral and sciatic nerve blocks have been used occasionally for unilateral total knee arthroplasty (TKA). In order to evaluate the effectiveness of this technique, combined femoral 3-in-1 and sciatic nerve blocks were performed in 20 cases of TKA, by the same surgeon. This surgeon also performed unilateral TKA under spinal anesthesia in another 20 cases. The anesthetic effectiveness of the two types of anesthesia was compared in terms of the time needed to complete the surgery, amount of intraoperative blood loss, and time interval until the first dose of analgesic. The results showed that the two types of anesthesia had comparable anesthetic effects. Ten of the 20 patients who had spinal anesthesia complained of postoperative urinary retention, while none of those who had nerve block had this complaint. Neither group experienced postpunctural headache, neurovascular damage, or drug-over-dose toxicity. We conclude that combined femoral 3-in-1 and sciatic nerve block is an effective anesthetic alternative for unilateral TKA.

Aged↗
PubMed1996

Rapid airway access by modified retrograde intubation.

Rapid access to the airway is important to ensure successful resuscitation. However, the establishment of a patent airway by orotracheal intubation is not always easy. This is especially true in patients with upper airway pathology or anatomic variations. A modified retrograde intubation technique was developed using the plastic sheath of the spring guidewire of a central venous pressure (CVP) kit as an introducer. This is considered to be a simple and safe method to provide a secure airway where intubation is difficult or in an emergency. This report presents our clinical experience using this method in 10 patients.

Emergencies↗
PubMed1992

Halothane alters the response of isolated airway smooth muscle to carbon dioxide.

Rings of canine bronchi were studied in vitro to determine the effects of halothane on the responses of airway smooth muscle to hypercapnia and hypocapnia. Bronchi were first contracted to 50% of maximal active force with acetylcholine (ACh), 5-hydroxytryptamine (5HT), potassium chloride (KCl), or the muscarinic agonist McN-A-343 (McN). The CO2 concentration of the bathing solution was then changed from 6% to either 1% (hypocapnia) or 10% (hypercapnia). In the absence of halothane, changes in CO2 concentration had no significant effect on muscles contracted with ACh. With all other contractile agonists, increasing the CO2 concentration caused bronchial relaxation, while decreasing the CO2 concentration caused contraction. In the presence of 2 MAC halothane, hypocapnia relaxed bronchi contracted with the muscarinic agonists ACh or McN; the responses to hypocapnia of bronchi contracted with KCl and 5HT were not significantly changed by halothane. Halothane had no effect on the responses of the bronchi to hypercapnia. We conclude that airway smooth muscle contracted with cholinergic agonist relaxes in response to hypocapnia when exposed to 2 MAC halothane; this mechanism may contribute to the depression of hypocapnic bronchoconstriction caused by halothane in vivo.

Animals↗
PubMed1991

Rapid and specific cyclosporine assay for the Du Pont aca discrete clinical analyzer performed directly on whole blood.

A rapid, sensitive, and specific enzyme immunometric assay for cyclosporine in whole blood has been developed for the aca analyzer, using a monoclonal antibody from Sandoz, Ltd. Between-run CVs ranged from 6.5 to 7.6% for samples containing between 60 and 400 ng/mL cyclosporine. Sensitivity was better than 25 ng/mL in the assay, which has an effective upper range of greater than 600 ng/mL. Two correlation studies compared cyclosporine values from the Du Pont method to those determined by HPLC procedures in three hospital laboratories. The results from a total of 120 whole blood samples with CsA between 20 and 800 ng/mL showed excellent correlation between the methodologies. HPLC and Du Pont CsA values from 10 day serial studies also correlated well for samples from a kidney, kidney-pancreas, heart, and two liver transplant patients. We conclude that the Du Pont CSA assay provides accurate and reproducible results in a convenient format in less than 30 minutes.

Autoanalysis↗
PubMed1989

The distance from the skin to the epidural space in a Chinese patient population.

The inter-relationship between age, height, weight and distance from the skin to the epidural space correlated with the patient's weight (r = 0.52, F = 23.96, P less than 0.001), and showed no correlation with patient's height (r = 0.18, F = 0.04, P greater than 0.05) or age (r = 0.13, F = 1.88, P greater than 0.05). The epidural space was found at a depth range of 3-7 cm, and 60% of patients had a depth of 4-5 cm. The results may be useful as a guideline for successful epidural blocks.

Adolescent↗
PubMed1987

Application of novel chromium dioxide magnetic particles to immunoassay development.

We have used chromium dioxide magnetic particles as the solid support in developing a series of immunological tests. The high surface area (greater than 40 m2/g) available on the magnetic particles and their easy dispersion throughout a solution allow for rapid and complete capture of the target antigen. The magnetic responsiveness of the particles allows for rapid, high-efficiency washing to reduce nonspecific binding, which often limits the sensitivity of serological assays. These features form the basis of extremely rapid and flexible assays for several hormones and markers of cancer and infectious disease. Most of the assays involve monoclonal antibodies. Here we describe specific performance characteristics for thyroxin, follitropin, creatine kinase isoenzyme MB, and antibody to human immunodeficiency virus (HIV). All of the assays are performed in less than 90 min, many in 30 to 45 min. The technology is highly flexible and is suitable for a variety of formats, from manual to fully automated.

Alkaline Phosphatase↗