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Biomedical subjects

P C Kam

Publications and source records attributed to P C Kam.

At least 19 recordsLinked to original sources
PubMed2001

The arterial tourniquet: pathophysiological consequences and anaesthetic implications.

The arterial tourniquet is widely used in upper and lower extremity surgery and in intravenous regional anaesthesia. The local and systemic physiological effects and the anaesthetic implications are reviewed. Localised complications result from either tissue compression beneath the cuff or tissue ischaemia distal to the tourniquet. Systemic effects are related to the inflation or deflation of the tourniquet. Safe working guidelines for the application of an arterial tourniquet have not been clearly defined.

Anesthesia, Conduction↗
PubMed2001

Anaphylactic or anaphylactoid reactions in patients undergoing cardiac surgery.

OBJECTIVE: To examine the clinical features, treatment, and outcome of anaphylactic and anaphylactoid reactions during cardiac surgery. DESIGN: Retrospective descriptive study. SETTING: A specialized referral anesthetic allergy clinic at a university teaching hospital. PARTICIPANTS: Twenty-three cardiac surgical patients referred after reactions resembling anaphylaxis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The database of the anesthetic allergy clinic was examined, and the data for patients who developed anaphylactic or anaphylactoid reactions were collated and summarized. Twenty-three cardiac surgical patients who experienced signs of anaphylactic or anaphylactoid reactions during anesthesia and surgery from 8 cardiac surgical centers in a major city were referred to the clinic. Cephalosporin antibiotics (30%) and gelatin solutions (Hemaccel) (26%) were the most common (56%) causes of the reactions. Most reactions occurred before the start of cardiopulmonary bypass. Although metaraminol was the first vasopressor used in 18 of 23 patients, it was not effective in 14 patients. Response to epinephrine was immediate and effective in 88% of cases. Rapid placement onto cardiopulmonary bypass facilitated a good outcome and permitted all but one operation to proceed as planned. No intraoperative or postoperative deaths were recorded. CONCLUSION: Of the anaphylactic and anaphylactoid reactions, 60% occurred before cardiopulmonary bypass, and these were caused by antibiotics and gelatin solution. The results from this limited database showed that cardiac surgery proceeded without complications after cardiovascular collapse caused by anaphylactic or anaphylactoid reactions. Rapid institution of cardiopulmonary bypass may be life-saving and should be considered.

Adolescent↗
PubMed2000

Cyclo-oxygenase isoenzymes: physiological and pharmacological role.

Prostaglandins play important roles in inflammation and the maintenance of normal physiological function of several organ systems. Prostaglandin production requires the conversion of arachidonic acid to the intermediate prostaglandin H2 catalysed by the cyclo-oxygenase (COX) enzyme. There are two isoforms of the COX enzyme, COX-1 and COX-2. These isoforms vary in their distribution and expression but are similar in size, substrate specificity and kinetics. Normal physiological functions are mediated by 'constitutive' COX-1, while the inflammatory response is mediated by 'inducible' COX-2. Current nonsteroidal anti-inflammatory drugs inhibit both enzymes to varying degrees and can cause adverse effects in the gastrointestinal tract, kidney, respiratory system and platelets. Newer, selective COX-2 inhibitors offer real hope for safer anti-inflammatory drugs although their long-term safety and efficacy need to be studied as questions remain unanswered about possible physiological functions of COX-2.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

Apoptosis: mechanisms and clinical implications.

The balance between cell survival and death is under tight genetic control. A multiplicity of extracellular signals and intracellular mediators is involved in maintaining this balance. When the cell is exposed to physical, biochemical or biological injury, or deprived of necessary substances, it activates a series of stress-response genes. With minimal insults, the cell may recover. With greater insults, single cell death, or apoptosis, results; the cell dies and is recycled to its neighbours. If the insult overwhelms a large number of cells then necrosis ensues, with an accompanying inflammatory response. Dysregulation of the controlling mechanisms of this system results in disease. Deficient apoptosis is associated with cancer, auto-immunity and viral infections. Excessive apoptosis is associated with ischaemic heart disease, stroke, neurodegenerative disease, sepsis and multiple organ dysfunction syndrome. There are myriad therapeutic options unfolding as understanding is gained of apoptosis and its control.

Apoptosis↗
PubMed1999

The physiological and pharmacological roles of cytochrome P450 isoenzymes.

The cytochrome P450 isoenzymes are a superfamily of haemoprotein enzymes that catalyse the metabolism of a large number of endogenous and exogenous compounds. Recently, the cytochrome isoenzymes have been shown to be important in the synthesis of steroid hormones and bile acids, the arachidonic acid cascade and in central nervous function. These enzymes are a major determinant of the pharmacokinetic behaviour of numerous drugs. Furthermore, alterations in cytochrome P450 activity have been implicated in some diseases.

Anesthetics↗
PubMed1999

Effect of haemorrhage on plasma propofol concentrations in a patient undergoing orthotopic liver transplantation.

We report a patient who underwent repeat orthotopic liver transplantation complicated by intraoperative blood loss of more than 59 litre. During liver transplantation, a constant rate propofol infusion was given and plasma samples were obtained throughout the procedure for propofol assay. Before the anhepatic phase of the procedure, plasma propofol concentrations reached a plateau at 1 microgram ml-1, and these concentrations were consistent with those predicted using a pharmacokinetic model. During the anhepatic phase of surgery, serum propofol concentrations increased progressively and exceeded those predicted by the pharmacokinetic model. Large intravascular fluid shifts associated with blood loss and subsequent blood replacement influenced plasma propofol concentrations observed in this patient.

Adult↗
PubMed1998

Gamma-hydroxybutyric acid: an emerging recreational drug.

Gamma-hydroxybutyric acid (GHB) is no longer used as an anaesthetic induction agent because of the high incidence of myoclonic seizures and vomiting. However, it is used occasionally in Europe for the treatment of narcolepsy, alcohol dependence and opiate dependence. Since the early 1990s, GHB has become a drug of abuse in youths for its euphoric, sedative and anabolic effects. Common adverse effects include a rapid onset of drowsiness, nausea, vomiting, myoclonic seizures and coma of short duration. Clinicians should be alert for these adverse effects and consider the possibility of GHB abuse in young adults with unusual clinical presentations in the emergency department.

Brain↗
PubMed1998

Behaviour of children associated with parental participation during induction of general anaesthesia.

OBJECTIVE: To evaluate children's behaviour during induction of general anaesthesia with parental participation. METHODS: A descriptive observational study in which the behaviour of the children was assessed using a Global Mood Scoring system before and during the induction of general anaesthesia, with their parents participating at induction. RESULTS: Parental participation in anaesthetic induction was beneficial in avoiding distress at parental separation without the use of preoperative sedation. Negative effects of parental participation were not encountered. CONCLUSIONS: Parental participation in anaesthetic induction of children can reduce distress at parental separation without any negative consequences. With proper preparation and education, parents should be encouraged to be present during the induction of general anaesthesia.

Analysis of Variance↗
PubMed1998

Administration of a crystalloid fluid preload does not prevent the decrease in arterial blood pressure after induction of anaesthesia with propofol and fentanyl.

Anaesthesia was induced in 58 women (ASA I or II) undergoing elective gynaecological procedures, using propofol 2.5 mg kg-1 and fentanyl 1.5 micrograms kg-1. Patients were allocated to receive 20 ml kg-1 of crystalloid fluid preload over 20 min or to receive no fluids before induction of anaesthesia. A significant decrease in systolic arterial pressure (< 75% of baseline value) occurred in both the fluid-loaded and the control groups, and was similar in both groups. Administration of a fluid preload did not attenuate the decrease in systolic arterial pressure after induction of anaesthesia with propofol and fentanyl.

Adult↗
PubMed1997

Frequency and duration of remission after isolated limb perfusion for melanoma.

OBJECTIVE: To examine the frequency and duration of complete remission for locally recurrent and metastatic limb melanoma after isolated limb perfusion (ILP) with cytotoxic agents. DESIGN: A case series of 114 consecutive therapeutic ILPs performed between April 1984 and April 1994 and a review of previously published studies. SETTING: A tertiary referral center for melanoma treatment, located at a university teaching hospital. RESULTS: Of 111 assessable ILPs, 81 (73%) resulted in complete limb tumor remission and 14 (13%) resulted in partial remission (defined as a reduction in size of tumor deposits by > 50%). Complete remission was maintained in 37 (46%) of the 81 cases without any further treatment (median follow-up, 33 months; range, 8-112 months). Of the other 44 cases, disease subsequently recurred in the perfused limb (median time to recurrence, 9.5 months; range, 2-65 months). In 19 of these cases, however, the limb was again disease free at last follow-up after local surgery (12 cases) or a repeat ILP (7 cases). Overall, complete locoregional control was achieved after 50% of assessable ILPs, and a long-term disease-free state in the limb was achieved, with or without further treatment, in 56 (69%) of the 81 cases in which an initial complete remission occurred. For 743 therapeutic ILPs undertaken in 12 series previously reported in the literature, an initial complete remission was reported in 50% of these cases and partial remission in 32%. CONCLUSION: Therapeutic ILP is an effective form of treatment for patients with recurrent and metastatic limb melanoma, achieving short- and long-term results that are superior to those achievable by any other form of treatment currently used.

Adult↗
PubMed1997

Peri-operative stroke in general surgical patients.

The incidence and aetiology of peri-operative stroke in patients undergoing general surgical procedures are reviewed. Some general recommendations on the peri-operative anaesthetic management of these patients are summarised.

Cerebrovascular Disorders↗
PubMed1997

Selective serotonin reuptake inhibitors. Pharmacology and clinical implications in anaesthesia and critical care medicine.

The newer, selective serotonin reuptake inhibitors are increasingly used in psychiatry in both children and adults. Although they have fewer side-effects, they can cause significant physiological changes and drug interactions which have implications for the anaesthetist and the critical care physician, especially the potential to induce the serotonin syndrome.

Adult↗
PubMed1997

Latex allergy: an emerging clinical and occupational health problem.

Allergy to latex products has become a problem of increasing dimensions, affecting both patients and health-care professionals. Certain high-risk groups and sources of latex exposure have been identified. The clinical manifestations vary from contact eczema through a range of allergic syndromes including life-threatening anaphylaxis. An understanding of the clinical and immunological features of latex allergy provides the basis of therapeutic and preventive strategies. Latex allergy is also becoming a major occupational health issue.

Anaphylaxis↗
PubMed1997

Occupational stress in anaesthesia.

Anaesthetists, like most in the medical profession, often deny that they may be suffering from work-related stress. This article explores the sources and effects of occupational stress with suggestions for dealing with the stresses of our specialty.

Alcoholism↗