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Biomedical subjects

K S Ng

Publications and source records attributed to K S Ng.

At least 19 recordsLinked to original sources
PubMed2001

Dual-site atrial pacing for atrial fibrillation in patients without bradycardia.

Atrial pacing has been shown to delay the onset of atrial fibrillation (AF) when compared with ventricular pacing in patients with sick sinus syndrome. The role for pacing in the control of AF in patients without bradycardia is uncertain. We performed a randomized, crossover, single-blinded study in 22 patients (14 women, aged 63 +/- 10 years) with paroxysmal AF refractory to treatment with oral sotalol (202 +/- 68 mg/day) and no bradycardic indication for pacing. All patients received a dual-chamber pacemaker with 2 atrial pacing leads positioned at the high right atrium and coronary sinus ostium, respectively. Patients were randomized in a crossover fashion to be paced for 12 weeks, either with high right atrial (RA) pacing at 30 beats/min ("Off") or dual-site RA pacing with an overdrive algorithm that maintained atrial pacing at a rate slightly above the sinus rate ("On"). Treatment on resulted in a significantly higher percentage of atrial pacing and a reduction in atrial ectopic frequency than the treatment off period. The time to the first clinical AF recurrence was prolonged (15 +/- 17 to 50 +/- 35 days, p = 0.006), and total AF burden was reduced (45 +/- 34% vs 22 +/- 29%, p = 0.04) in the on-treatment phase. However, there was no difference in AF checklist symptom scores or overall quality-of-life measures. Dual-site RA pacing with continued sinus overdrive prolonged the time to AF recurrence and decreased AF burden in patients with paroxysmal AF. The absence of a major impact on symptom control suggests that pacing should be used as an adjunctive therapy with other treatment modalities for AF.

Adolescent↗
PubMed2001

Effect of different endotracheal suctioning systems on cardiorespiratory parameters of ventilated patients.

INTRODUCTION: We conducted this prospective randomised cross-over study to evaluate the effect of closed system (CS) versus open system (OS) endotracheal suctioning on heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR), oxygen saturation (SpO2) and electrocardiogram (ECG) rhythm of patients on mechanical ventilation. MATERIALS AND METHODS: Fourteen adult patients were randomly allocated to receive either CS or OS suctioning in the first instance. For the subsequent suctioning, they were crossed over to the alternate suctioning system. The various cardiorespiratory parameters were recorded at BL1 (baseline 1), S1 (first suction pass), BL2 (baseline 2, i.e. immediately post first suction pass), S2 (second suction pass), T2 (2 minutes post suction) and T5 (5 minutes post suction). RESULTS: Compared to CS, OS suctioning was found to result in higher HR at S1 (P < or = 0.05) and S2 (P < or = 0.05); higher MAP at BL2 (P < or = 0.05); lower SpO2 at BL2 (P < or = 0.01) and S2 (P < or = 0.01). There was no significant difference in RR between the two suctioning systems. OS suctioning was also noted to result in a significantly higher incidence of arrhythmia (P < = or 0.05). CONCLUSION: Our study shows that OS suctioning results in more adverse changes in cardiorespiratory parameters compared to CS suctioning.

APACHE↗
PubMed2000

Initial experience of radiofrequency catheter ablation of supraventricular tachycardia in paediatric patients.

INTRODUCTION: The management of supraventricular tachycardia (SVT) in paediatric patients until recently has frequently been pharmacologic therapy, but this approach suffers from the drawbacks of treatment failure, development of drug intolerance and/or side-effects. AIM: In keeping with recent advances in paediatric cardiology, we share our experience with radiofrequency catheter ablation as an alternative and definitive modality of therapy. MATERIALS AND METHOD: 4 young patients with recurrent SVT underwent electrophysiologic study followed by radiofrequency ablation of the accessory pathways. RESULTS: Resolution of symptoms was achieved in all patients and no major complication was encountered. CONCLUSIONS: The ability to ablate permanently the reentrant circuit responsible for SVT has now permitted cure by non-surgical means, and is an important alternative to drug therapy in the management of SVT in children.

Adolescent↗
PubMed1999

Dissemination of respiratory secretions during tracheal tube suctioning in an intensive care unit.

Most intensive care patients require frequent tracheal toilet, a procedure usually performed by suctioning the tracheal tube. Such procedures often result in the production and dissemination of droplets. We measured the distance visible droplets disseminated during tracheal tube suctioning of patients in an adult surgical intensive care unit. Fifty consecutive suction procedures in 14 patients intubated with a cuffed tracheal tube were investigated. Visible droplets were scattered over a mean distance of 60 +/- 39 cm (range 25 to 168 cm) from the tracheal tube. Blood agar culture plates were placed at three fixed points from the tracheal tube to identify organisms resulting from environmental contamination (control plates). This was repeated during suctioning procedures (study plates) to look into the occurrence of bacteriological cultures that differ from the control plates. Nine of the 14 patients had tracheal tube aspirate cultures done as part of their work-up for sepsis. In more than 30% of the suctioning procedures on these 9 patients, study plates grew bacteria that were similar to those present in their tracheal tube aspirates. In view of these observations, greater care should be taken to avoid contamination of the patient's immediate environment during tracheal tube suctioning and in the design of the intensive care unit.

Acinetobacter↗
PubMed1998

The athlete's heart: is this an entity in paediatrics?

A case report of a boy who demonstrates features of an athlete's heart, associated with dilatation of the coronary artery, is presented. The importance of distinguishing this benign condition from pathologic causes such as cardiomyopathy, and risk of sudden death in these athletes is discussed.

Adolescent↗
PubMed1998

Endogenous source of bacteria in tracheal tube and proximal ventilator breathing system in intensive care patients.

Although bacteria from both the ventilator breathing system and the gastrointestinal tract have been implicated in the pathogenesis of ventilator-associated pneumonia, an endogenous source of bacteria in the proximal respiratory breathing system has yet to be demonstrated conclusively. We investigated a potential route of bacterial colonization from the stomach contents to the efferent limb of the ventilator breathing system by bacterial culture of daily specimens from six sites in 20 surgical intensive care patients. Gram-negative bacilli were isolated in a progressively increasing proportion of samples at successive sampling points, consistent with an endogenous-to-external route of spread (patients, chi-square = 14.12, P < 0.02; samples, chi-square = 106.15, P < 0.001). Identical strains of gram-negative bacilli, confirmed by REPS typing, were found at two or more sites in seven patients. In all seven, gram-negative bacilli were first isolated from a site in the patient. In none of the 20 patients was there evidence of a sequence of colonization from the ventilator tubing or Y-piece connector towards the patient. Probable colonization sequences plotted from the time of first isolation supported the proposed sequence in six patients, and in five began with the stomach contents. Isolation sequences contrary to the proposed direction of colonization involved four bacterial species and two patients, and did not extend beyond two sample sites. These findings imply that the retrograde route of bacterial colonization of the ventilated lung extends into the proximal respiratory breathing system and may help to identify additional targets for preventive intervention.

Adult↗
PubMed1998

Cardiac dysrrhthmia in systemic disease.

This is an ECG of a 6-year-old girl. She presented to us for management of epilepsy. Magnetic resonance imaging (MRI) of the brain showed multiple lesions consistent with cortical and subcortical tubers. There were also achromic spots on her skin and echocardiography demonstrated a rhabdomyoma near the right ventricular outflow tract. A diagnosis of tuberous sclerosis, an autosomal-dominantly inherited condition, was made. What is abnormal about the ECG?

Child↗
PubMed1996

Correlation of P-wave polarity with underlying electrophysiologic mechanisms of long RP' tachycardia.

Analysis of surface electrocardiograms from patients with long RP' tachycardia due to either atypical atrioventricular node reentrant tachycardia, permanent junctional reciprocating tachycardia, or low atrial tachycardia was performed. Although a negative P wave in the inferior leads is common to all 3 mechanisms, the results suggest that a positive or isoelectric P wave in electrocardiographic lead I strongly supports a diagnosis of atypical atrioventricular node reentrant tachycardia, whereas a negative or biphasic P wave in lead I argues against this mechanism.

Adult↗
PubMed1996

Malposition of a long central venous catheter in the right inferior thyroid vein--a case report.

This case report hopes to bring to attention the possibility of malposition and ligation of a long central venous catheter in a central venous tributary in the course of major neck surgery. A 49-year-old gentleman underwent total laryngectomy and right radical neck dissection for laryngeal carcinoma. A long central venous catheter was inserted via the right basilic vein. This was subsequently found to have malpositioned into the right inferior thyroid vein and ligated. It required an exploration of the neck wound to remove the ligated catheter.

Catheterization, Central Venous↗