Search PubMed⌕ Search

Biomedical subjects

K M Ho

Publications and source records attributed to K M Ho.

At least 55 records · Page 3Linked to original sources
PubMed2000

The use of intravenous atropine after a saline infusion in the prevention of spinal anesthesia-induced hypotension in elderly patients.

UNLABELLED: We investigated the efficacy of IV atropine for preventing spinal anesthesia-induced hypotension in elderly patients. Seventy-five patients undergoing transurethral prostate or bladder surgery were randomized to receive either placebo (n = 25), atropine 5 microg/kg (small-dose atropine, n = 25) or atropine 10 microg/kg (large-dose atropine, n = 25) after the induction of spinal anesthesia. All the patients received an IV infusion of 10 mL/kg 0.9% normal saline over 10 min before the induction of anesthesia. The systolic blood pressure decreased in all three groups after spinal anesthesia. There was a significant increase in the mean heart rate in both atropine groups as compared to the placebo group (placebo group: 78 bpm, 95% confidence interval [CI]: 76.6-78.5; small-dose atropine group: 86 bpm, 95% CI 83.9-88.8; large-dose atropine group: 97 bpm, 95% CI 94.5-100.3; P: = 0.001). There was a significant decrease in the incidence of hypotension in patients who received atropine (placebo group: 76%, small-dose atropine group: 52%, large-dose atropine group: 40%, P: = 0.03). The mean dose of ephedrine required was significantly decreased in the atropine groups (placebo group: 12.2 mg [SD= 10.5], small-dose atropine group: 7.4 mg [SD= 10.0], large-dose atropine group: 5.4 mg [SD= 8.7 mg], P: = 0.048). The total amount of IV fluid and number of patients requiring metaraminol in addition to 30 mg of ephedrine were not significantly different among the three groups. Significant side effects, such as confusion, ST segment changes or angina were not detected in any of the patients. We conclude that IV atropine may be a useful supplement to the existing methods in preventing hypotension induced by spinal anesthesia. IMPLICATIONS: IV atropine increases heart rate in a dose-dependent manner in elderly patients undergoing spinal anesthesia. It reduces the incidence of hypotension and the dose of ephedrine required. Small-dose atropine may be a useful supplement in preventing spinal anesthesia-induced hypotension in elderly patients.

Aged↗
PubMed1999

A comparison of the Internet and the standard textbook in preparing for the professional anaesthetic examination.

The Internet is increasingly being recognised as a source of information in different fields, and medicine is no exception. We investigated the use of the Internet as an aid in preparing for the professional medical examinations. The Internet was compared to a standard textbook in answering a randomly selected past examination paper. Thirty-eight web-sites on the Internet were involved, giving information to all the examination questions. In contrast, the textbook provided adequate information in only 73.3% of the questions. The time required to search for information on the Internet was more than that required for a single textbook. (approximately 2 hours per question compared to 30 minutes per question respectively). However, with the rapid development of computer technology and the cyberspace, the Internet may prove to be a viable alternative or a good supplement to the standard textbook when trainee anaesthetists are preparing for their professional medical examinations.

Anesthesiology↗
PubMed1999

The use of mini-dose suxamethonium to facilitate the insertion of a laryngeal mask airway.

The use of mini-dose suxamethonium to facilitate the insertion of a laryngeal mask airway was investigated. Sixty patients were assigned randomly in a double-blind manner to receive 0.9% sodium chloride or suxamethonium 0.1 mg.kg-1 intravenously, following intravenous induction with propofol 2.5 mg.kg-1. The laryngeal mask was inserted after the first attempt in 87% of patients. Mini-dose suxamethonium improved the correct positioning of the laryngeal mask during the first attempt (93 vs. 67%, p < 0.02), decreased the incidence of swallowing (p < 0.001), gagging (p < 0.001) and head or limb movement (p < 0.05). Laryngeal mask insertion was graded as easy in 93% of patients who had mini-dose suxamethonium, compared with 60% in the placebo group (p < 0.01). The duration of apnoea between the two groups was not significantly different (0.54 vs. 0.61 min, p = 0. 46). The total dose of propofol needed to insert the laryngeal mask was lower in the suxamethonium group (2.57 vs. 3.25 mg.kg-1, p < 0. 01) and was associated with less hypotension (p < 0.05). Fasciculation (17%) and mild myalgia (23%) were common despite the small dose of suxamethonium used. In conclusion, mini-dose suxamethonium facilitates laryngeal mask insertion. Myalgia is common and the technique is not recommended for patients who are prone to suxamethonium myalgia.

Adolescent↗
PubMed1999

Co-localization of carbon monoxide and nitric oxide synthesizing enzymes in the human urethral sphincter.

PURPOSE: Ineffective relaxation of the urethral sphincter during micturition can result in obstructive voiding symptoms. Several studies suggest carbon monoxide (CO) acts alongside nitric oxide (NO) as an inhibitory neurotransmitter, and may regulate NO production. We have investigated the distribution of the constitutive CO producing enzyme, heme oxygenase-2 (HO-2) and the NO producing enzyme, neuronal nitric oxide synthase (nNOS), in the human urethra. MATERIALS AND METHODS: Transverse cryostat sections (12 microns.) were cut from three male membranous and six female urethrae. Double immunofluorescence was carried out for co-localization of HO-2 with nNOS using standard methodology. RESULTS: Nerve trunks showing both HO-2 and nNOS immunoreactivities were identified in the urethrae in both sexes. In the female urethrae, of 152 ganglionic cell bodies expressing HO-2 or nNOS immunoreactivity, 74.3% exhibited both HO-2 and nNOS immunoreactivities, 25% exhibited only HO-2 immunoreactivity and 0.7% exhibited only nNOS immunoreactivity. CONCLUSIONS: Immunoreactivity for HO-2 has been demonstrated in neuronal structures innervating the male and female urethral sphincters. The dual expression of HO-2 with nNOS immunoreactivity in cell bodies and nerves suggests that there is an interaction between the CO and NO generating systems. Abnormality in these systems may play a role in urethral dysfunction.

Carbon Monoxide↗
PubMed1998

A comparison of central venous pressure and common iliac venous pressure in critically ill mechanically ventilated patients.

OBJECTIVE: To investigate the possibility of using common iliac venous pressure (CIVP) as an alternative to superior vena cava pressure (SVCP) in mechanically ventilated, critically ill, adult patients. DESIGN: A randomized, blinded comparison. SETTING: Multidisciplinary intensive care unit at a university teaching hospital. PATIENTS: Twenty mechanically ventilated, critically ill, adult patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All patients had a catheter in situ for measuring the SVCP. A new triple-lumen catheter, with a length ranging from 15 to 20 cm, was placed into the common iliac vein via the femoral route. The SVCP and CIVP were simultaneously measured at hourly intervals for 6 hrs. Positive end-expiratory pressure, mean airway pressure, and intra-abdominal pressure were measured at the same time intervals. For 140 paired measurements of CIVP and SVCP in 20 patients, the mean difference was 0.1 +/- 1.06 (SD) mm Hg (95% confidence interval -0.10 to 0.25); the limits of agreement were -2.04 to 2.20 mm Hg (95% confidence interval -2.34 to 2.50). Mean airway pressure, intra-abdominal pressure, and positive end-expiratory pressure had no measurable effect on the difference between SVCP and CIVP. Serious complications arising from insertion of the catheter through the femoral route were not observed. CONCLUSION: For clinical purposes, CIVP measured by a catheter of 15 to 20 cm placed through the femoral route is interchangeable with SVCP in mechanically ventilated adult patients. This finding provides an alternative route for assessment of central venous pressure when other routes are not appropriate.

Abdomen↗
PubMed1998

Nitric oxide synthase in the heterogeneous population of intramural striated muscle fibres of the human membranous urethral sphincter.

PURPOSE: Nitric oxide (NO) is known to relax urethral smooth muscle. The role of NO in the control of urethral striated muscle remains unknown. We have investigated the distribution of nitric oxide synthase (NOS) immunoreactivity and its possible relationship with subtypes of intramural striated muscle fibers in the human male membranous urethra. MATERIALS AND METHODS: Whole transverse cryostat sections from seven membranous urethrae were studied using NOS immunohistochemistry and NADPH diaphorase histochemistry. Striated fiber subtypes were demonstrated using immunohistochemistry for troponin T and histochemistry for myofibrillary adenosine triphosphatase (ATPase). Consecutive sections were used to assess the correlation between the distribution of NOS immunoreactivity and the type of striated fibers. RESULTS: NOS immunoreactivity and NADPH diaphorase activity were detected in the sarcolemma of 48.5% of the intramural striated muscle fibers. NOS immunoreactive nerve trunks and fine nerve fibers, a few of which appeared to end on muscle fibers, were present in the striated sphincter. Fast twitch fibers were detected by ATPase staining, and also exhibited positive immunoreactivity for troponin T, constituting 34.6% of the total number of striated fibers. Two populations of slow twitch fibers were identified; one with small diameter (mean: 15.7 microns) and another of larger diameter (mean: 21.7 microns) comparable to that of fast twitch fibers. 86% of the fast twitch fibers and 29% of slow twitch fibers (most of which had larger diameters) exhibited NOS immunoreactivity and NADPH diaphorase activity in the sarcolemma. CONCLUSIONS: The presence of nitrergic nerve fibers in the striated urethral sphincter suggests an involvement in the innervation of urethral striated muscle. Furthermore, the presence of NOS immunoreactivity in the sarcolemma may indicate a role for NO in the regulation of urethral striated muscle metabolism and contraction.

Adolescent↗
PubMed1997

Delayed upper airway obstruction. A life-threatening complication of Dettol poisoning.

Dettol liquid is a commonly used household disinfectant and although it is labelled nonpoisonous, serious respiratory complications have been reported in up to 8% of cases of Dettol ingestion. We report a case in which the delayed onset of upper airway obstruction was treated with emergency awake, fibreoptic guided nasotracheal intubation. Based on information available in published cases and on our own experience, we suggest that patients who have ingested large volumes of Dettol, have a history of vomiting or unprotected lavage, or have evidence of ongoing oropharyngeal inflammation, are at high risk of this complication. They should be closely observed for at least 48 h after ingestion and the facilities and staff required for emergency airway management should be immediately available.

Aged↗
PubMed1997

Gastric tonometry and prediction of outcome in the critically ill. Arterial to intramucosal pH gradient and carbon dioxide gradient.

Splanchnic ischaemia is thought to be of central importance in the development of multi-organ failure and hence death in critically ill patients. It has been suggested that the arterial to gastric intramucosal pH gradient and the difference in partial pressure of carbon dioxide between gastric mucosa and arterial blood are more sensitive markers of splanchnic ischaemia than gastric intramucosal pH itself and thus should be predictors of mortality in the critically ill. We studied 62 critically ill patients within 6 h of admission to the intensive care unit and found no significant difference at 0, 12 or 24 h after admission to the study in either the arterial to gastric intramucosal pH gradient or the difference in partial pressure of carbon dioxide between gastric mucosa and arterial blood between survivors and nonsurvivors. We conclude that in contrast to gastric intramucosal pH neither the arterial to gastric intramucosal pH gradient nor the difference in partial pressure of carbon dioxide between gastric mucosa and arterial blood distinguish survivors from nonsurvivors.

Adult↗