PubMed Health⌕ Search

Biomedical subjects

A de Boer

Publications and source records attributed to A de Boer.

At least 37 records · Page 2Linked to original sources
PubMed2001

Antihypertensive drug therapies and the risk of ischemic stroke.

BACKGROUND: The relative effectiveness of various antihypertensive drugs with regard to the reduction of stroke incidence remains uncertain. OBJECTIVE: To assess the association between first ischemic stroke and use of antihypertensive drugs. METHODS: A population-based case-control study was performed among enrollees of the Group Health Cooperative of Puget Sound. Case patients included pharmacologically treated hypertensive patients who sustained a first ischemic stroke (fatal or nonfatal; n = 380) between July 1, 1989, and December 31, 1996. Control subjects were a random sample of treated hypertensive enrollees without a history of a stroke (n = 2790). Medical record review and a telephone interview of consenting survivors were used to collect information on risk factors for stroke. Computerized pharmacy records were used to assess antihypertensive drug use. RESULTS: Among 1237 single-drug users with no history of cardiovascular disease, the adjusted risk of ischemic stroke was higher among users of a beta-blocker (risk ratio [RR], 2.03; 95% confidence interval [CI], 1.05-3.94), calcium channel blocker (RR, 2.30; 95% CI, 1.16-4.56), or angiotensin-converting enzyme inhibitor (RR, 2.79; 95% CI, 1.47-5. 27) than among users of a thiazide diuretic alone. Among 673 single-drug users with a history of cardiovascular disease, the RRs were 1.22 (95% CI, 0.63-2.35), 1.18 (95% CI, 0.59-2.33), and 1.45 (95% CI, 0.70-3.02) among users of a beta-blocker, calcium channel blocker, and angiotensin-converting enzyme inhibitor, respectively, compared with users of a thiazide diuretic alone. CONCLUSIONS: In this study of pharmacologically treated hypertensive patients, antihypertensive drug regimens that did not include a thiazide diuretic were associated with an increased risk of ischemic stroke compared with regimens that did include a thiazide. These results support the use of thiazide diuretics as first-line antihypertensive agents.

Adrenergic beta-Antagonists↗
PubMed2001

Antipsychotic-induced extrapyramidal syndromes. Risperidone compared with low- and high-potency conventional antipsychotic drugs.

AIM: To compare the risk of extrapyramidal syndromes (EPS) between patients using risperidone and those using low-potency conventional antipsychotic drugs (APDs) in outpatient clinical practice, as measured by the use of anticholinergic medication. We tried to replicate results from previous clinical trials that compared risperidone with high-potency APDs. METHOD: Data was obtained from the PHARMO database containing filled prescriptions of 450,000 community-dwelling people in The Netherlands from 1986 to 1998. From the patients aged 15-54 years who had been newly treated with APDs, we defined mutually exclusive cohorts according to the APD first prescribed to a patient. APD exposure was followed until the first prescription of anticholinergic medication and was censored when APD prescribing was interrupted or switched. We estimated relative risks between risperidone and commonly used low-potency and high-potency APDs using Cox proportional hazards models, adjusting for age, gender, dose and other potential confounders. RESULTS: In 4094 patients who had been newly prescribed antipsychotic drugs, the overall incidence rate of anticholinergic drug therapy was 556 per 1000 person-years, which was dose dependent. Prescribed doses of all antipsychotics were low. While, in accordance with previous trials, risperidone showed a lower risk of EPS than the high potency APDs such as haloperidol (RR 0.26; 95% CI 0.10-0.64), we did not observe a lower EPS rate than low-potency APDs (risperidone vs thioridazine RR 1.73, 95% CI 0.49-6.13; risperidone vs pipamperone RR 2.50, 95% CI 0.78-8.04). CONCLUSION: The reduced EPS rates observed when comparing risperidone with high-potency antipsychotics such as haloperidol may not apply to comparisons with low-potency drugs.

Adolescent↗
PubMed2001

Do the research goal and databases match? A checklist for a systematic approach.

To test the appropriateness of a given database for specific research questions, we designed a checklist starting with the definition of an ideal database. This ideal database contains all relevant data on patients, providers and services. It is safe and accessible, input is always accurate, continuity is guaranteed and linkage with other information is easy. Of course no such database exists. Still these features are often taken for granted, but highly influenced by organizational processes in healthcare and prioritization. Starting with the characteristics of an ideal database, one can systematically list the required aspects for research goals and compare these with the available systems. This checklist is used to address important aspects of administrative database research and ethical issues. The increasing possibility to misuse sensitive data needs to be discussed by researchers, administrators, individuals and society. This checklist can also be valuable to others to design or interpret studies based on claims databases.

Benchmarking↗
PubMed2001

Comparison of different methods to estimate prevalence of drug use by using pharmacy records.

Several methods to estimate prevalence of drug use are available, which may complicate a valid comparison of these estimates. Standardization may contribute to more valid comparisons. We compared different methods to estimate prevalence of drug use by using pharmacy records. Data were obtained from the Dutch population-based PHARMO-database comprising medication histories of 300,000 subjects. Five point prevalences and a 1-year prevalence of cholesterol-lowering drug use were estimated in 1995. Four point prevalences differed in data handling before estimating prevalence (e.g., correction for irregular drug use or construction of episodes of drug use). The numerator of the fifth point prevalence estimate represented the number of defined daily doses (DDDs) instead of the number of patients filling a prescription. The first four point prevalences ranged from 11.0-12.1 per thousand. Prevalence ratio (male:female) was 1.2 for these methods. The fifth method resulted in an estimate similar to the other point prevalences (11.9 DDDs/1000 inhabitants). However, the prevalence ratio was 1.4 due to larger average number of DDDs prescribed to men. One year-prevalence was 4-5 per thousand higher than point prevalences. The comparison of these methods indicated that the choice of prevalence measure (point versus period prevalence) substantially influenced the prevalence estimate, whereas the influence of data handling was negligible. For standardization purposes in drug utilization research, we recommend estimating point prevalence instead of period prevalence. The various methods of data handling before estimating point prevalence yielded similar results and therefore we cannot recommend one specific method. However, defined daily doses should not be used to estimate (point) prevalences of drug use because this measure is significantly influenced by prescribed dosage regimens.

Adult↗
PubMed2001

Evaluation of antiparkinsonian drugs in pharmacy records as a marker for Parkinson's disease.

AIM: The aim of this study was to determine whether use of antiparkinsonian drugs in pharmacy records can be used as a marker for patients with Parkinson's disease (PD). METHOD: Data were obtained from the Rotterdam Study, a community-based prospective cohort study among people aged 55 years or older who were all screened for PD. For 5510 persons, of whom 74 had PD, pharmacy records were available. Stepwise logistic regression analysis was used to evaluate whether age, sex and use of the antiparkinsonian drugs amantadine, anticholinergics, dopamine agonists, levodopa and selegiline, were predictive variables for PD. For each individual a probability for having PD was calculated. Sensitivity, specificity and positive predictive value (PPV) were calculated at different cut-off values based on calculated probabilities. RESULTS: More than 90% of the users of levodopa, bromocriptine, selegiline, and users of at least two different antiparkinsonian drugs had PD. Age, use of amantadine, anticholinergics, bromocriptine, levodopa, and selegiline were predictive variables for PD. After application of different cut-off values, sensitivity was at most 66.2%, and specificity was at least 99.8%. A PPV of higher than 90% was obtained at higher probabilities. CONCLUSION: Based on the high PPV of our predictive model, antiparkinsonian drugs can be used as a reliable marker for PD in pharmacy records. Because sensitivity is low, pharmacy records cannot be used to estimate prevalence of PD.

Aged↗
PubMed2001

The association between antihypertensive drug therapies and plasma lipid levels in the general population.

OBJECTIVE: To assess the association between different antihypertensive drug regimens and plasma lipid levels in the general population. METHODS: The Monitoring Project on Cardiovascular Risk Factors was conducted from 1987 to 1991 as a cross-sectional study in The Netherlands. Antihypertensive drug-users and untreated hypertensives were selected. After exclusion of users of cholesterol-lowering drugs 2997 subjects remained for the analysis. The plasma lipid concentrations of the users and non-users of antihypertensives were compared by multiple linear regression. RESULTS: In the univariate analysis patients using beta-blockers had lower high-density lipoprotein (HDL) concentrations (1.13 mmol/l, P < 0.05) and higher cholesterol ratios (5.74, P < 0.05) than untreated hypertensives (Total cholesterol = 6.07 mmol/l, HDL = 1.20 mmol/l and ratio = 5.44). Patients using diuretics had higher total cholesterol levels (6.34 mmol/l) and higher HDL levels (1.26 mmol/l) compared to untreated hypertensives. After adjustment for possible confounders these differences were smaller and no longer statistically significant. After adjustment we found a significant lower HDL cholesterol (mean difference of -0.10 mmol/l, P < 0.05) for users of a combination of a beta-blocker and a diuretic. CONCLUSIONS: Although randomised, controlled trials have demonstrated that antihypertensive drugs may influence plasma lipid levels we observed no substantial association for single antihypertensive drug therapy in the general population. The combination of a diuretic and a beta-blocker was associated with a worse lipid profile.

Adrenergic beta-Antagonists↗
PubMed2001

Thoracic and thoracoabdominal aortic aneurysm repair: use of evoked potential monitoring in 118 patients.

PURPOSE: Paraplegia is the most dreaded and severe complication of surgery on the descending thoracic aorta (TAA) and thoracoabdominal aorta (TAAA). The functional integrity of the spinal cord can be monitored by means of intraoperative recording of myogenic-evoked responses after transcranial electrical stimulation (tcMEP) and somatosensory-evoked potential (SEP) monitoring. In this study, we evaluated the results of evoked potential monitoring and the adequacy of the strategy followed. METHOD: The spinal cord of 118 patients (78 men; age, 65 +/- 12 years; 79 TAAAs, 39 TAAs) undergoing surgery on the TAA or TAAA was monitored with tcMEP and SEP. Spinal cord protection was achieved by means of a multimodality approach: moderate hypothermia (32 degrees C rectal temperature), continuous cerebrospinal fluid drainage to keep the pressure less than 10 mm Hg, reimplantation of intercostal arteries, left ventricular bypass grafting, and staged clamping. In the case of evoked potential changes more than 50% of baseline, the strategy was adjusted: reattachment of more segmental arteries when technically feasible, higher distal and proximal perfusion pressures, and enhanced cerebrospinal fluid drainage. RESULTS: Forty-two of 118 patients (35.6%) had a more than 50% of baseline tcMEP reduction during cross-clamping. At this point, only 5 of those 42 cases were also associated with SEP reduction of more than 50% of baseline. On the basis of the tcMEP findings, the strategy was adjusted. Five patients had postoperative paraplegia (4.2%). CONCLUSION: tcMEP monitoring seems to be a useful adjunct of the protective techniques and may cause substantial adjustments in strategy, reducing the incidence of postoperative paraplegia.

Aged↗
PubMed2001

Is drug treatment of hypertension in clinical practice as effective as in randomized controlled trials with regard to the reduction of the incidence of stroke?

The results from several nonexperimental studies suggest that drug treatment of hypertension in daily clinical practice may not be as effective as in randomized controlled trials. These nonexperimental studies had limitations with regard to the selection of an appropriate control group. The objective of our study was to assess the effect of drug treatment of hypertension under circumstances of everyday medical practice on the incidence of stroke by using a prognostically comparable untreated reference group. Within two prospective, population-based cohort studies among 45,000 men and women 20 years of age and older in the Netherlands, we selected a cohort of 2,301 hypertensive subjects who either received drug treatment for hypertension (N = 1,318) or were untreated for hypertension but were determined to be "candidates" for drug treatment on the basis of their level of blood pressure and the presence of other cardiovascular risk factors (N = 983). Follow-up averaged 4.6 years and was complete for 91% of the hypertensives. Compared with untreated hypertensive subjects who were "candidates" for drug treatment, subjects who received drug treatment for hypertension had, after adjustment for potential confounders, a 39% [95% confidence interval (CI) = 3-61%] reduced risk of stroke. About 46 (95% CI = 29-599) hypertensive patients need to be treated with antihypertensive drugs for 5 years to prevent one stroke in the general Dutch population. When a prognostically comparable reference group is used, the drug treatment of hypertension under circumstances of everyday medical practice appears to be effective in the reduction of the incidence of stroke. The relative risk reduction that we found was similar to those found in randomized controlled trials.

Aged↗
PubMed2001

Risk of extrapyramidal syndromes with haloperidol, risperidone, or olanzapine.

OBJECTIVE: To compare the risk of extrapyramidal syndrome (EPS) between risperidone, olanzapine, and haloperidol, taking into account patients' past antipsychotic drug use and past EPS. METHODS: Data were obtained from the PHARMO-database, containing filled prescriptions of 450,000 community-dwelling people in the Netherlands from 1986 through 1999. We defined cohorts of first-time users of haloperidol, risperidone, or olanzapine aged 15 to 54 years. In the first 90 days of treatment, we assessed the occurrence of EPS, defined as first use of any antiparkinsonian agent. We estimated relative risks of EPS for risperidone and olanzapine versus haloperidol using a Cox proportional hazards model. Patients were subdivided according to prior use of antipsychotic and antiparkinsonian drugs. RESULTS: We identified 424 patients starting treatment with haloperidol, 243 with risperidone, and 181 with olanzapine. Prior use of antipsychotic plus antiparkinsonian medication was significantly more frequent among users of risperidone and olanzapine than in those using haloperidol (36.2%, 40.3%, and 4.5%, respectively; p < 0.001). Within most subgroups of comparable treatment history, patients using risperidone and olanzapine showed reduced risks of EPS compared with haloperidol, although some of these findings did not reach statistical significance (RR 0.03-0.22). However, this was not observed for patients using risperidone who had experienced EPS in the past (RR 1.30; 95% CI 0.24 to 7.18). CONCLUSIONS: In general, we observed reduced risks of EPS for risperidone and olanzapine compared with haloperidol within subgroups of patients with a similar treatment history. However, the added value of risperidone in patients who have experienced EPS in the past needs further study.

Adolescent↗
PubMed2001

Drug-Induced lipid changes: a review of the unintended effects of some commonly used drugs on serum lipid levels.

Many drugs besides lipid-lowering drugs affect serum lipid levels in either a potentially harmful or beneficial way, and may therefore increase or decrease the risk of cardiovascular disease. Diuretics, beta-blocking agents, progestogens, combined oral contraceptives containing 'second generation' progestogens, danazol, immunosuppressive agents, protease inhibitors and enzyme-inducing anticonvulsants adversely affect the lipid profile. They increase total cholesterol, low density lipoprotein cholesterol and triglycerides by up to 40, 50 and 300%, respectively, and decrease high density lipoprotein cholesterol by a maximum of 50%. Conversely, alpha-blocking agents, estrogens, hormone replacement therapy, combined oral contraceptives containing 'third generation' progestogens, selective estrogen receptor modulators, growth hormone and valproic acid show mostly beneficial effects on the lipd profile. Some drugs, for example, isotretinoin, acitretin and antipsychotics, mainly elevate triglyceride levels. Adverse or beneficial effects on serum cholesterol levels do not always translate into a higher or lower, respectively, incidence of cardiovascular disease. because these drugs may influence cardiovascular risk through multiple pathways. In some cases, excessive cholesterol levels occur, for example, with protease inhibitor therapy, and several cases of pancreatitis attributable to drug-induced hypertriglyceridaemia have been reported. Some general guidelines on the management of drug-induced dyslipidaemia can be given. Replacement of the dyslipidaemia-inducing drug by an equivalent alternative therapy is preferred. However, such alternatives are often difficult to find. If there is no equivalent alternative and treatment with the dyslipidaemia-inducing drug must be initiated, monitoring of serum lipid levels is important. If drug use is expected to be long term, the existing guidelines for the management of dyslipidaemia in the general population can be applied to drug-induced dyslipidaemia. In cases of extreme hyperlipidaemia, medication use should be reassessed.

Adult↗
PubMed2000

Influence of question structure on the recall of self-reported drug use.

Epidemiological studies often rely on self-reported information as a source of drug exposure. Several studies have evaluated the accuracy of self-reported information on drug use. The influence of question structure on the accuracy of recall, however, has not been studied extensively in these studies. In this study we examined the recall accuracy of questionnaire information on drug use in a ongoing public health survey with special attention to the influence of question structure on sensitivity of recall. A sample of 372 hypertensive subjects for whom questionnaire information and pharmacy records were available was examined. Self-reported information on drug use was obtained through questions about medications used for a specific condition and one final open-ended question. This information was compared with the pharmacy medication history. About 71% of all drugs that were currently in use according to the pharmacy records were recalled through the self-administered questionnaire, and 94% of all drugs mentioned in the questionnaire could be traced in the pharmacy records. Recall sensitivity was higher for questions about medications used for a specific indication (88%) than for the open-ended question (41%). The type of drug that was used might have caused part of this difference in recall. We conclude that questionnaire structure might be of influence on the accuracy of recall of self-reported drug use, and more attention should be paid to the structure of questions on drug use.

Adult↗
PubMed2000

Hapten-induced colitis associated with maintained Th1 and inflammatory responses in IFN-gamma receptor-deficient mice.

IFN-gamma is a potent pro-inflammatory cytokine thought to be involved in the pathogenesis of Crohn's disease. To further define the role of IFN-gamma in intestinal inflammation, we studied the effects of intra-colonic 2,4,6-trinitrobenzene sulfonic acid (TNBS) instillation in mice with a functionally inactivated IFN-gamma receptor 1 (IFN-gammaR1(- / -)). Our results indicate that IFN-gamma is not necessary for the induction of hapten-induced colitis: after TNBS administration both wild-type and IFN-gammaR1(- / -) mice lost body weight, and the histological features of TNBS-induced colitis were comparable. Colons of IFN-gammaR1(- / -) mice contained a greater number of cells, represented by macrophages and CD4(+) T cells; caudal lymph node cells produced more IFN-gamma and TNF-alpha upon stimulation in vitro. Moreover, IL-18 and IL-12 p40 RNA levels were comparably up-regulated after TNBS treatment in IFN-gammaR1(- / -) wild-type mice. These findings demonstrate that IFN-gamma is dispensable for the development of TNBS-induced colitis. Importantly, the production of Th1 cytokines (e. g. IFN-gamma and TNF-alpha) by caudal lymph node T lymphocytes was enhanced rather than decreased in IFNgammaR1(- / -) mice with no evidence for default Th2 development.

Animals↗
PubMed2000

Estimating the prevalence of hypertension corrected for the effect of within-person variability in blood pressure.

The objective of our study was to assess the applicability of using estimates of within-person variance (WPV) from reproducibility studies for a correction of blood pressure values in another study to improve the accuracy of the prevalence estimation of hypertension. Data were collected from two cross-sectional population-based studies on cardiovascular disease risk factors conducted from 1987 to 1995 among 55,026 subjects aged 20-59 years. Correction factors were calculated from a reproducibility study among 924 subjects who were examined in 1989 and 1990. All other studies with repeated measurements of blood pressure were searched in MEDLINE from 1966 onward. Six studies satisfied the inclusion criteria. The prevalence of hypertension, uncorrected and corrected with factors from other studies, were compared with the prevalence of hypertension corrected with the factor from our study. The uncorrected prevalence of hypertension was 17.3% [95%CI:17.0-17.7]. The prevalence of hypertension after correction for WPV with the factor from our study was 13.5% [95%CI:13.2-13.8]. Correction for WPV with factors from the appropriate studies (depending on factors such as number of measurements taken per visit, and time interval between visits) resulted in prevalences ranging from 13.9% to 14.7%. The bias that occurs when no correction for WPV is performed is much larger (29% overestimation) than the bias that occurs when correction factors are derived from other studies (3.1-8.4% overestimation). When repeated measurements of blood pressure are not available in a population study for a sample of that same study, it is advisable to use data from another study to correct for WPV.

Adult↗
PubMed2000

Use of prevalence and incidence measures to describe age-related prescribing of antidepressants with and without anticholinergic effects.

To evaluate whether physicians avoid prescribing highly anticholinergic antidepressants (AAD) in the elderly, a population-based retrospectively data analysis was performed using databases from a Dutch health insurance company. Data collected on approximately 240,000 persons covered the period from 1 July 1993 to 1 January 1996. The prevalence and the incidence (number of new starters) of antidepressant use was measured over 1994 and 1995. Use of AAD was proportionally higher in the elderly in terms of both prevalence and incidence rates; the ratio of starters of AAD versus starters of non-AAD in 1994 increased steadily with age (from 0.54 in the age group 20-29 to 1.15 in the age group 60-69). In 1995 these incidence ratios decreased (0.41 to 0.99, respectively); however, the decrease was higher in the younger age groups. The data indicate that in the population studied, physicians do not refrain from prescribing highly anticholinergic agents to older patients despite their potential adverse drug reactions in this age group. This study also indicates that prevalence and incidence rates can be extracted from reimbursement data and give insight into actual prescribing practices.

Adult↗
PubMed2000

Influence of correction for within-person variability in blood pressure on the prevalence, awareness, treatment, and control of hypertension.

We assessed the influence of correction for within-person variability (WPV) on the prevalence, awareness, treatment, and control of hypertension. Data were collected from two cross-sectional population-based studies on cardiovascular disease risk factors from 1987 to 1995 among 56,026 subjects aged 20 to 59 years. Correction factors were calculated from an internal reproducibility study among 924 subjects who were examined in 1989 and 1990. The prevalence of hypertension without a correction of blood pressure values for WPV was substantially overestimated (38%), whereas the prevalence of awareness and treatment of hypertension were substantially underestimated (-13% and -28%). The prevalence of control of hypertension did not change much after this correction. It may be advisable to perform a correction for within-person variability to obtain valid prevalence estimates in surveys that only take one or two measurements of blood pressure.

Adult↗
PubMed2000

Sex differences in the medication choice for hypertension in general practice. A study with written case simulations.

The objective of this study was to explore explanations for the preference of physicians to prescribe beta-blockers to hypertensive men and diuretics to hypertensive women. A qualitative study among 12 family physicians was conducted with a combination of written case simulations, semi-structured interviews and statements on attitudes of physicians towards antihypertensive drug choice. Among the male hypertensive cases the most frequently prescribed drugs were beta-blockers, whereas among the female hypertensive cases diuretics were more often prescribed. Physician characteristics associated with a preferred prescribing of beta-blockers to hypertensive men and diuretics to hypertensive women were: older age (no residency in family medicine), the believe that beta-blockers are more effective in men with regard to lowering blood pressure and that diuretics are more effective in women, a non-evidence based attitude and a sex-related attitude towards the choice of beta-blockers and diuretics in general, and in particular towards the prescribing of beta-blockers to hypertensive men because men have a higher absolute risk of coronary heart disease than women. An additional explanation for these findings may be the higher prevalence of ankle oedema among women. Patient characteristics associated with more prescribing of beta-blockers to hypertensive men and diuretics to hypertensive women were: current employment and a "high-risk" profile in terms of blood pressure level and additional cardiovascular risk factors. Although, most considerations underlying a preferred prescribing of beta-blockers to hypertensive men and diuretics to hypertensive women were not evidence-based, the actual choice of antihypertensive drug (diuretic or beta-blocker) was evidence-based. These considerations may also play a role in the sex difference in the choice of calcium antagonists and angiotensin converting enzyme inhibitors and require further investigation.

Adrenergic beta-Antagonists↗
PubMed2000

The effect of two low-dose propofol infusions on the relationship between six-pulse transcranial electrical stimulation and the evoked lower extremity muscle response.

BACKGROUND: Transcranial stimulation of the motor cortex using high-voltage electrical stimuli given in train is a method of monitoring the integrity of the motor pathways during thoracoabdominal aortic aneurysm surgery. The purpose of this study was to assess the relationship between the stimulus intensity and the corresponding amplitude of the myogenic motor evoked potential (tcMEP) in response to six-pulse transcranial electrical stimulation during two levels of low-dose propofol infusion and stable fentanyl/nitrous oxide anaesthesia. METHODS: Nine patients (37-78 yr) scheduled to undergo surgery on the thoracoabdominal aorta were studied. After achieving a stable anaesthetic state the output voltage was decreased with 50 V intervals from 350 V to 200 V during a target propofol infusion aimed at a plasma steady-state concentration of 0.7 microg x ml(-1) and increased with 50 V intervals from 200 V to 450 V during a target propofol infusion aimed at a plasma steady-state concentration of 1.4 microg x ml(-1). TcMEPs were recorded from the right tibialis anterior muscle. RESULTS: Doubling the target propofol infusion to 1.4 microg x ml(-1) resulted in a 30-50% decrease in tcMEP amplitude. The largest tcMEP amplitude using the six-pulse paradigm was found during a propofol infusion aimed at a plasma concentration of 0.7 microg x ml(-1) and demanded a stimulus output of 350 V, corresponding to a charge density of 7.5 microC x cm(-2) per phase. CONCLUSION: Doubling the target propofol infusion to 1.4 microg x ml(-1) provides less robust, but still recordable tcMEPs in response to six-pulse electrical stimulation. Safety guidelines are discussed.

Adjuvants, Anesthesia↗