Predictors of the variability in neuromuscular block duration following succinylcholine: A prospective, observational study.

BACKGROUND: The duration of neuromuscular block (NMB) following succinylcholine administration is characterised by a high interindividual variability. However, this has not yet been quantified in a large sample of surgical patients. The significance of underlying clinical factors is unknown. OBJECTIVE: The objective of this study was to profile the variability in NMB duration following a standard dose of succinylcholine and to investigate contributing clinical and genetic factors. DESIGN: A prospective, observational study. SETTING: Tertiary referral centre. PATIENTS: In a total of 1630 surgical patients undergoing a rapid sequence induction and intubation, clinical risk factors for a prolongation in NMB duration following succinylcholine were assessed. In a subset of 202 patients, additional biochemical and molecular genetic investigations of butyrylcholinesterase were performed. INTERVENTION: A standard 1 mg kg dose of succinylcholine after administration of an induction drug and an opioid. MAIN OUTCOME: NMB duration measured as the time between administration of succinylcholine until reappearance of palpable muscular response to supramaximal transcutaneous ulnar nerve stimulation. RESULTS: NMB varied from 80 s to 44 min with a median duration of 7.3 min. Sixteen percent of patients had NMB duration in excess of 10 min. A multivariable survival model identified physical status, sex, age, hepatic disease, pregnancy, history of cancer and use of etomidate or metoclopramide as independent risk factors for a prolonged NMB. Three novel butyrylcholinesterase variants were identified: p.Ile5Thr; p.Val178Ile; and p.Try231Ser. CONCLUSION: Neuromuscular blockade duration in excess of 10 min occurred in 16% of a general surgical population following a single dose of succinylcholine. The multivariable model of clinical risk factors for prolonged NMB revealed a negative predictive value of 87%, thereby indicating that absence of such risk factors may reliably predict a shorter duration of NMB. In patients with clinical risk factors for a prolonged NMB or with butyrylcholinesterase mutations, an alternative to succinylcholine should be considered.

Evaluation of a standardized internet-based and telephone-based patient monitoring system for pain therapy with transdermal fentanyl.

The aim of the present observational 4-week study was to document the feasibility and utility of telephone-based or Internet-based pain monitoring in patients with chronic cancer or noncancer pain, such as nociceptive or neuropathic pain, using transdermal fentanyl. Pain intensity, treatment tolerability, activities of daily living, quality of life, and patient and physician satisfaction were evaluated in 60 (60% women, 42% opioid-naive) chronic pain patients who were switched from oral pain therapy to transdermal fentanyl therapy because of persisting severe pain. When the total dataset of all patient entries was analyzed, treatment with transdermal fentanyl led to decreases in maximal and mean pain scores as reported by the patients (-14% and -19%, respectively, last observation carried forward vs. baseline). Pain reduction was more pronounced in opioid-naive than in opioid-experienced patients (-35% and -25% vs. baseline, respectively; P=0.03). Overall, impairment of daily activities was reduced by 23% with transdermal fentanyl. No effect was observed with regard to quality of life and use of rescue pain medication. Transdermal fentanyl was generally well tolerated. Most patients (60%) preferred the telephone-based to the Internet-based or Internet combined with telephone questionnaires. Patient preference was driven by age, whereby younger patients tended to prefer the Internet and older patients the telephone (mean age, 45 and 54 y, respectively; difference n.s.). Internet-based and telephone-based monitoring of the efficacy and tolerability of opioid treatment for chronic pain was feasible in daily practice and generally well accepted by patients and physicians. Future research will determine the relative contribution of these 2 new options for patient-physician interaction and delineate their role in improving chronic pain control.