Comparison of alfetanil and ketamine in combination with propofol for patient-controlled sedation during fiberoptic bronchoscopy

BACKGROUND: During fiberoptic bronchoscopy, propofol, ketamine, benzodiazepines, and opiates are most commonly used, alone or in combination for sedation. The aim of this study was to compare the clinical efficacy of propofol/ketamine with propofol/alfentanil for patient-controlled sedation (PCS) during fiberoptic bronchoscopy. METHOD: Patients undergoing fiberoptic bronchoscopy were randomly assigned to receive either propofol/alfentanil (PA group; n = 138) or propofol/ketamine (PK group; n = 138) via a patient-controlled analgesia (PCA) device for sedation and analgesia. Changes in blood pressure, heart rate (HR), and oxygen saturation were monitored. Degree of patient and bronchoscopist satisfaction was evaluated using a 10-cm visual analog scale (VAS) (0 = extremely uncomfortable to 10 = extremely comfortable). RESULTS: After sedation, systolic arterial pressure (SAP) decreased in the PA group, but SAP was stable in the PK group. Compared with values immediately before starting bronchoscopy, SAP and HR increased during the procedure in both groups (P < 0.05). Patients in the PK group showed more satisfaction [(9.5 (6-10) vs. 9.0 (6-10)), P < 0.05] and amnesia (82% vs. 61%, P < 0.01). Despite these differences, the majority (greater than 90%) of the patients in both groups stated that they were comfortable during the procedure. CONCLUSION: Our results show that although both techniques proved effective for sedation in patients undergoing fiberoptic bronchoscopy, ketamine is superior to alfentanil when used in combination with propofol because of the high patient satisfaction and amnesia.     

Childhood exposure to environmental tobacco smoke and chronic respiratory symptoms in non-smoking adults: the Singapore Chinese Health Study

BACKGROUND: Childhood exposure to environmental tobacco smoke has been extensively associated with childhood respiratory illness; fewer studies have addressed the effects on adults. METHODS: Childhood environmental tobacco smoke exposure in relation to chronic cough, phlegm, and asthma diagnosis was studied in never smokers from a cohort of Singaporeans of Chinese ethnicity aged 45-74 years at enrollment from 1993 to 1998. From 1999 to 2004 subjects were interviewed regarding environmental tobacco smoke exposure before and after the age of 18 and the presence and duration of current symptoms of chronic cough and phlegm production and asthma diagnosis. RESULTS: Among 35,000 never smokers, fewer had smoking mothers (19%) than fathers (48%). Although few subjects currently lived (20%) or worked (4%) with smokers, 65% reported living with a daily smoker before the age of 18 years. Living with a smoker before the age of 18 increased the odds of chronic dry cough (149 cases, odds ratio 2.1, 95% CI 1.4 to 3.3) and, to a lesser extent, phlegm, after adjustment for age, sex, dialect group, and current and past exposure to smokers at home and at work after the age of 18. Associations strengthened with higher numbers of smokers in childhood. There was no association with asthma or chronic bronchitis. There was evidence to suggest a stronger association among subjects with a lower adult intake of fibre which has previously been found to be protective for respiratory symptoms. CONCLUSIONS: In this large study of non-smokers, living with a smoker in childhood was associated with chronic dry cough and phlegm in adulthood, independent of later exposures to environmental tobacco smoke.     

Incidence of lower thoracic ligamentum flavum midline gaps

Background. Lower thoracic epidural anaesthesia and analgesia(EDA) has gained increasing importance in perioperative paintherapy. The loss-of-resistance technique used to identify theepidural space is thought to rely on the penetration of theligamentum flavum. Investigations at the cervical and lumbarregions have demonstrated that the ligamentum flavum frequentlyexhibits incomplete fusion at different vertebral levels. Therefore,the aim of this study was to directly investigate the incidenceof lower thoracic ligamentum flavum midline gaps in embalmedcadavers. Methods. Vertebral column specimens were obtained from 47 humancadavers. Ligamentum flavum midline gaps were recorded betweenthe vertebral levels T₆ and L₁. Results. The incidence of midline gaps/number of viable specimensat the following levels was: T_6–7: 2/45 (4.4%), T_7–8:1/47 (2.1%), T_8–9: 2/45 (4.4%), T_9–10: 7/39 (17.9%),T_10–11: 12/34 (35.2%), T_11–12: 10/35 (28.5%), T₁₂/L₁:6/38 (15.8%). Conclusions. In the present study we have determined the frequencyof lower thoracic ligamentum flavum midline gaps. Gaps are lessfrequent than at cervical levels, but more frequent than atlumbar levels. Peak incidence was found in the region betweenT₁₀ and T₁₂. Using a strict midline approach, one cannot thereforerely on the ligamentum flavum to impede entering the epiduralspace in all patients.      

Rate-dependent AV delay optimization in cardiac resynchronization therapy

BACKGROUND: During cardiac resynchronization therapy (CRT), cardiac performance is dependent on an optimized atrioventricular delay (AVD). However, the optimal AVD at different heart rates has not been defined yet during CRT. METHOD: The effects of an increase in heart rate by pacing or physical exercise on optimal AVD were studied in 36 patients with biventricular pacemakers/defibrillators. The velocity time integral (VTI) in the left ventricular outflow tract (LVOT) was measured with pulsed Doppler either at three different paced heart rates in the supine position or in seated position before and after physical exercise. RESULTS: The baseline AVD was optimized to 99 +/- 19 ms in the supine and 84 +/- 22 ms in the seated position. When the heart rate was increased by DDD pacing, there was a positive linear relationship between an increase in heart rate, in AVD and in VTI (LVOT-VTI + 0.047 cm/s per 10 beats per minute (bpm) heart rate increase per 20 ms increase in AVD, P = 0.007). A similar but more pronounced relationship was found after physical exercise in the seated position (LVOT-VTI + 0.146 cm/s per 10 bpm heart rate increase per 20 ms increase of AVD, P = 0.013). This effect was observed in patients with and without AV block and mitral regurgitation. CONCLUSIONS: In conclusion, the systolic performance of the dilated ventricle, which depends on an elevated preload, is critically affected by the appropriate timing of the AVD during exercise. In contrast to normal pacemaker patients, in CRT the relatively short baseline AVD should be prolonged at increased heart rates. Further studies with other means of measuring exercise cardiac performance are needed to confirm these unexpected findings.