J Klein

Erasmus MC, Rotterdam, South Holland, Netherlands

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Publications (32)81.86 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the combined beneficial effect of statin and beta-blocker use on perioperative mortality and myocardial infarction (MI) in patients undergoing abdominal aortic aneurysm surgery (AAA). Patients undergoing elective AAA-surgery identified by clinical risk factors and dobutamine stress echocardiography (DSE) as being at high-risk often have considerable cardiac complication rate despite the use of beta-blockers. We studied 570 patients (mean age 69 ±9 years, 486 males) who underwent AAA-surgery between 1991 and 2001 at the Erasmus MC. Patients were evaluated for clinical risk factors (age>70 years, histories of MI, angina, diabetes mellitus, stroke, renal failure, heart failure and pulmonary disease), DSE, statin and beta-blocker use. The main outcome was a composite of perioperative mortality and MI within 30 days of surgery. Perioperative mortality or MI occurred in 51 (8.9%) patients. The incidence of the composite endpoint was significantly lower in statin users compared to nonusers (3.7% vs. 11.0%; crude odds ratio (OR): 0.31, 95% confidence interval (CI): 0.13-0.74; p = 0.01). After correcting for other covariates, the association between statin use and reduced incidence of the composite endpoint remained unchanged (OR: 0.24,95% CI: 0.10-0.70; p = 0.01). Beta-blocker use was also associated with a significant reduction in the composite endpoint (OR: 0.24, 95% CI: 0.11-0.54). Patients using a combination of statins and beta-blockers appeared to be at lower risk for the composite endpoint across multiple cardiac risk strata; particularly patients with 3 or more risk factors experienced significantly lower perioperative events. A combination of statin and beta-blocker use in patients with AAA-surgery is associated with a reduced incidence of perioperative mortality and nonfatal MI particularly in patients at the highest risk.
    European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery 09/2011; 42 Suppl 1:S96-104. DOI:10.1016/j.ejvs.2011.06.016 · 3.07 Impact Factor
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    ABSTRACT: Nearly 60% of the Dutch population undergoing surgery is aged 65 years and over. Older patients are at increased risk of developing perioperative complications (e.g., myocardial infarction, pneumonia, or delirium), which may lead to a prolonged hospital stay or death. Preoperative risk stratification calculates a patient's risk by evaluating the presence and extent of frailty, pathophysiological risk factors, type of surgery, and the results of (additional) testing. Type of anesthesia, fluid management, and pain management affect outcome of surgery. Recent developments focus on multimodal perioperative care of the older patient, using minimally invasive surgery, postoperative anesthesiology rounds, and early geriatric consultation.
    Zeitschrift für Gerontologie + Geriatrie 06/2011; 44(3):187-91. DOI:10.1007/s00391-011-0201-6 · 1.02 Impact Factor
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    ABSTRACT: To assess surgical team members' differences in perception of non-technical skills. Questionnaire design. Operating theatres (OTs) at one university hospital, three teaching hospitals and one general hospital in the Netherlands. Sixty-six surgeons, 97 OT nurses, 18 anaesthetists and 40 nurse anaesthetists. All surgical team members, of five hospitals, were asked to complete a questionnaire and state their opinion on the current state of communication, teamwork and situation awareness at the OT. Ratings for 'communication' were significantly different, particularly between surgeons and all other team members (P ≤ 0.001). The ratings for 'teamwork' differed significantly between all team members (P ≤ 0.005). Within 'situation awareness' significant differences were mainly observed for 'gathering information' between surgeons and other team members (P < 0.001). Finally, 72-90% of anaesthetists, OT nurses and nurse anaesthetists rated routine team briefings and debriefings as inadequate. This study shows discrepancies on many aspects in perception between surgeons and other surgical team members concerning communication, teamwork and situation awareness. Future research needs to ascertain whether these discrepancies are linked to greater risk of adverse events or to process as well as systems failures. Establishing this link would support implementation and use of complex team interventions that intervene at multiple levels of the healthcare system.
    International Journal for Quality in Health Care 03/2011; 23(2):159-66. DOI:10.1093/intqhc/mzq079 · 1.58 Impact Factor
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    ABSTRACT: To assess the predictive value of walking distance after an exercise test on long-term outcome in patients with normal and impaired ankle-brachial index (ABI). A total of 2191 patients with known or suspected peripheral arterial disease (PAD), who were referred for a single-stage treadmill exercise test to diagnose or evaluate their PAD, were enrolled in an observational study between 1993 and 2006. They were divided into two groups: normal ABI (>or=0.90) and impaired ABI (<0.90). Walking distance was divided into quartiles (no (reference), mild, moderate or severe impairment). In patients with normal ABI, severe walking distance was, after adjustment, associated with higher mortality risk (hazard ratio (HR): 2.60 (range: 1.16-5.78)). In patients with impaired ABI, all walking distance impairment quartiles were associated with higher mortality (mild HR: 1.26 (range: 0.95-1.67), moderate HR: 1.52 (range: 1.13-2.05) and severe HR: 1.69 (range: 1.26-2.27)). Furthermore, comparable associations were observed between all walking distance quartiles, cardiac death or major adverse cerebrovascular and cardiac events. Our study illustrated that walking impairment is a strong prognostic indicator of long-term outcome in patients with impaired and normal ABI, which should be a warning sign to physicians to monitor these patients carefully and to provide them optimal treatment.
    European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery 08/2009; 38(4):482-7. DOI:10.1016/j.ejvs.2009.02.022 · 3.07 Impact Factor
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    ABSTRACT: Early recovery of patients following sedation/analgesia and anesthesia is important in ambulatory practice. The aim of this study was to assess whether modafinil, used for the treatment of narcolepsy, improves recovery following sedation/analgesia. Patients scheduled for extracorporeal shock wave lithotripsy were randomly assigned to one of four groups. Two groups received a combination of fentanyl/midazolam with either modafinil or placebo. The remaining groups received remifentanil/propofol with either modafinil or placebo. Modafinil 200 mg was administered to the treatment group patients 1 h before sedation/analgesia. Groups were compared using the digital symbol substitution test (DSST), trail making test (TMT), observer scale of sedation and analgesia (OAA/S) and Aldrete score. Verbal rating scale (VRS) scores for secondary outcome variables e.g. energy, tiredness and dizziness were also recorded before and after treatment. Sixty-seven patients successfully completed the study. Groups received similar doses of sedation and analgesic drugs. No statistically significant difference was found for DSST between groups. No significant adverse effects occurred in relation to modafinil. No statistically significant difference between groups was identified for TMT, OAA/S and Aldrete scores. The mean VRS score for tiredness was lesser in the modafinil/fentanyl/midazolam group [1.3 (2.0)] compared with the placebo group [3.8 (2.5)], P=0.02. Such a difference was not found between the remifentanil/propofol groups [placebo 2.6 (2.2) vs. modafinil 3.1(2.7)], p>0.05. Dizziness was greater in the modafinil/remifentanil/propofol group 1.7 (2.0) vs. placebo 0.0 (0.5), p<0.05. Modafinil reduces patient-reported tiredness after sedation/analgesia but does not improve recovery in terms of objective measures of patient psychomotor skills.
    Acta Anaesthesiologica Scandinavica 08/2009; 54(2):154-61. DOI:10.1111/j.1399-6576.2009.02093.x · 2.31 Impact Factor
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    E Blommers · M Klimek · J Klein · P G Noordzij
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    ABSTRACT: Nearly 60% of the Dutch population undergoing surgery is over the age of 65. The elderly are at higher risk of developing perioperative complications (e.g. myocardial infarction, pneumonia or delirium), that lead to a prolonged hospital stay or death. Preoperative risk stratification calculates the patient's risk by evaluating the presence and extent of frailty, and pathophysiological risk factors, type of surgery and the results of additional testing. The type of anaesthesia, fluid management and pain management strongly influences the outcome of surgery and the way this is experienced by the patient. Recent developments focus on multimodal perioperative care of the older patient to shorten hospital stay, using minimal invasive surgery, postoperative anaesthesiology rounds and early geriatric consultation.
    Nederlands tijdschrift voor geneeskunde 08/2008; 152(27):1513-7.
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    ABSTRACT: Sugammadex is the first selective relaxant binding agent and reverses rocuronium-induced neuromuscular block. A case is reported in which a patient accidentally received a high dose of sugammadex (40 mg kg-1) to reverse a rocuronium-induced (1.2 mg kg-1) profound neuromuscular block. A fast and efficient recovery from profound neuromuscular block was achieved and no adverse events or other safety concerns were reported.
    BJA British Journal of Anaesthesia 06/2007; 98(5):624-7. DOI:10.1093/bja/aem057 · 4.35 Impact Factor
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    ABSTRACT: To study whether beta-blockers reduce in-hospital and long-term mortality in patients with severe left ventricular dysfunction (LVD) undergoing major vascular surgery. Observational cohort study. Five hundred and eleven patients with severe LVD (ejection fraction<30%) undergoing major non-cardiac vascular surgery. In all patients, cardiac risk factors, medication (including beta-blockers), and dobutamine stress echocardiography (DSE) results were noted prior to surgery. DSE was evaluated for rest and stress-induced new wall motion abnormalities. Endpoint was in-hospital and long-term mortality. Propensity scores for beta-blockers were calculated and regression models were used to analyse the relation between beta-blockers and mortality. Mean age was 64+/-11 years and 383 patients (75%) were male. 139 patients (27%) used beta-blockers. Stress-induced ischemia occurred in 82 patients (16%). Median follow-up was 7 years (interquartile range: 3-10). In-hospital and long-term mortality was observed in 64 (13%) and 171 (33%) patients, respectively. After adjusting for clinical variables, DSE results and propensity scores, beta-blockers were significantly associated with reduced in-hospital and long-term mortality (OR: 0.18, 95% CI: 0.04-0.74 and HR: 0.38, 95% CI: 0.22-0.65, respectively). In patients with severe LVD undergoing major vascular surgery, the use of beta-blockers is associated with a reduced incidence of in-hospital and long-term postoperative mortality.
    European Journal of Vascular and Endovascular Surgery 04/2006; 31(4):351-8. DOI:10.1016/j.ejvs.2005.10.018 · 3.07 Impact Factor
  • P. Palanchon · A. Bouakaz · J. Klein · N. de Jong
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    ABSTRACT: The classification of circulating microemboli as gaseous or particulate matter is essential to establish the relevance of the detected embolic signals. Until now, Doppler techniques have failed to determine unambiguously the nature of circulating microemboli. Recently, a new approach based on the analysis of radio frequency (RF) signal and using the nonlinear characteristics of gaseous bubbles to classify emboli was investigated. The main limitation of these studies was the requirement of two separate transducers for transmission and reception. This paper presents a multi-frequency transducer with two independent transmitting elements and a separate receiving part with a wide frequency band. The transmitting elements are positioned in a concentric design and cover a frequency band between 100 and 600 kHz. The receiving part consists of a polyvinylidene fluoride layer. The new transducer has been tested in vitro using gaseous emboli. It could correctly classify and size air emboli with diameters ranging from 10 μm to 105 μm.
    IEEE Transactions on Biomedical Engineering 01/2006; 52(12-52):2087 - 2092. DOI:10.1109/TBME.2005.857641 · 2.23 Impact Factor
  • H C Rettig · M J M Gielen · E Boersma · J Klein
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    ABSTRACT: This prospective, randomized study compared the efficacy of the vertical infraclavicular and axillary approaches using a single injection blockade of the brachial plexus. The primary endpoint was complete blockade in dermatomes C5-Th1, while secondary endpoints included onset time, motor block, block performance time, surgical success rate, patient satisfaction, and side-effects/complications. Sixty patients, American Society of Anesthesiologists physical status I or II, scheduled for surgery of the forearm or hand received either a vertical infraclavicular (n = 30) or an axillary block (n = 30). A single injection of 0.5 ml/kg ropivacaine 7.5 mg/ml was made after electrolocalization of nerve fibres corresponding to the median nerve at maximum 0.5 mA (2 Hz, 0.1 ms). Onset and distribution of analgesia and motor block were assessed at 5, 10, 15, 20, 30 and 60 min after the local anaesthetic injection. A complete block was defined as analgesia in all dermatomes (C5-Th1) at 60 min post-injection. The vertical infraclavicular approach provided complete blockade in 29 patients (97%) and the axillary approach in 23 patients (77%). Analgesia in C5-C6 dermatomes and corresponding motor block occurred significantly more frequently in the vertical infraclavicular approach, which also had the shortest onset time. Block procedure was quicker in the axillary approach. Side-effects were similar in both groups, and there were no permanent sequelae. Patient satisfaction was equally high in both groups. The vertical infraclavicular approach provides a more complete block than the axillary approach when using a single injection technique and equal volumes/doses of local anaesthetic.
    Acta Anaesthesiologica Scandinavica 12/2005; 49(10):1501-8. DOI:10.1111/j.1399-6576.2005.00816.x · 2.31 Impact Factor
  • ACC Current Journal Review 08/2005; 14(8):7. DOI:10.1016/j.accreview.2005.08.014
  • European Journal of Anaesthesiology 05/2005; 22(Supplement 34). DOI:10.1097/00003643-200505001-00382 · 3.01 Impact Factor
  • European Journal of Anaesthesiology 05/2005; 22(Supplement 34). DOI:10.1097/00003643-200505001-00042 · 3.01 Impact Factor
  • European Journal of Anaesthesiology 05/2005; 22(Supplement 34). DOI:10.1097/00003643-200505001-00068 · 3.01 Impact Factor
  • D Poldermans · J Klein
    European Heart Journal – Cardiovascular Imaging 01/2005; 5(6):403. DOI:10.1016/j.euje.2004.10.002 · 4.11 Impact Factor
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    M.D. Kertai · E. Moersma · J. Klein
    Journal of Vascular Surgery 11/2004; 40(5):1060. DOI:10.1016/j.jvs.2004.09.010 · 2.98 Impact Factor
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    ABSTRACT: To investigate the combined beneficial effect of statin and beta-blocker use on perioperative mortality and myocardial infarction (MI) in patients undergoing abdominal aortic aneurysm surgery (AAA). Patients undergoing elective AAA-surgery identified by clinical risk factors and dobutamine stress echocardiography (DSE) as being at high-risk often have considerable cardiac complication rate despite the use of beta-blockers. We studied 570 patients (mean age 69+/-9 years, 486 males) who underwent AAA-surgery between 1991 and 2001 at the Erasmus MC. Patients were evaluated for clinical risk factors (age>70 years, histories of MI, angina, diabetes mellitus, stroke, renal failure, heart failure and pulmonary disease), DSE, statin and beta-blocker use. The main outcome was a composite of perioperative mortality and MI within 30 days of surgery. Perioperative mortality or MI occurred in 51 (8.9%) patients. The incidence of the composite endpoint was significantly lower in statin users compared to nonusers (3.7% vs. 11.0%; crude odds ratio (OR): 0.31, 95% confidence interval (CI): 0.13-0.74; p=0.01). After correcting for other covariates, the association between statin use and reduced incidence of the composite endpoint remained unchanged (OR: 0.24, 95% CI: 0.10-0.70; p=0.01). Beta-blocker use was also associated with a significant reduction in the composite endpoint (OR: 0.24, 95% CI: 0.11-0.54). Patients using a combination of statins and beta-blockers appeared to be at lower risk for the composite endpoint across multiple cardiac risk strata; particularly patients with 3 or more risk factors experienced significantly lower perioperative events. A combination of statin and beta-blocker use in patients with AAA-surgery is associated with a reduced incidence of perioperative mortality and nonfatal MI particularly in patients at the highest risk.
    European Journal of Vascular and Endovascular Surgery 10/2004; 28(4):343-52. DOI:10.1016/j.ejvs.2004.07.008 · 3.07 Impact Factor
  • P. Palanchon · A. Bouakaz · J Klein · N de Jong
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    ABSTRACT: The classification of circulating microemboli as gaseous or particulate matter is essential to establish the relevance of detected embolic signals. Transcranial Doppler (TCD) technology has not yet fully succeeded in characterizing the composition of microemboli unambiguously. Recently, the authors proposed a new approach to detect, characterize and size gaseous emboli. The method is based on the nonlinear properties of gaseous bubbles. The application of this approach requires a dedicated transducer with the ability to transmit the adequate frequencies and simultaneously receive the high frequency scattered nonlinear components. The paper presents a multifrequency emboli transducer composed of two independent transmitting elements and a separate receiving part. The transmitting part can cover a frequency band between 100 kHz and 600 kHz. The reception of the signal is performed by a 110 μm PVDF layer sensitive over a frequency band ranging from 50 kHz to 2 MHz. Experimental results show that a specific range of gaseous embolus size was detected by each transmitting element. Using the 130 kHz outer element in transmission, microemboli between 35 μm and 105 μm can be discriminated through their second harmonic or subharmonic emissions while gaseous microemboli between 10 μm and 40 μm were accurately classified using the 360 kHz inner element. The in vitro results demonstrate that nonlinear properties of microemboli combined with the new transducer offer a real opportunity to characterize and size microemboli.
    Ultrasonics Symposium, 2004 IEEE; 09/2004
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    ABSTRACT: Cardiac troponin T (cTnT) is a sensitive and specific marker for myocardial injury, but elevations of cTnT without clinical evidence of ischemia and persistent or new electrocardiographic (ECG) abnormalities are common in patients undergoing major vascular surgery. We explored the long-term prognostic value of cTnT levels in these patients. A follow-up study was conducted between 1996-2000 in 393 patients who underwent successful aortic or infrainguinal vascular surgery and routine sampling of cTnT. Patients were followed until May 2003 (median of 4 years [25th-75th percentile, 2.8-5.3 years]). Total creatine kinase (CK), CK-MB, and cTnT were routinely screened in all patients, and included sampling after surgery and the mornings of postoperative days 2, 3 and 7. Electrocardiograms were also routinely evaluated for sign of ischemia. An elevated cTnT was defined as serum concentrations >/=0.1 ng/ml in any of these samples. All-cause mortality was evaluated during long-term follow-up. Eighty patients (20%) had late death. The incidence of all-cause mortality (41% vs. 17%; p<0.001) was significantly higher in patients with an elevated cTnT level compared to patients with normal cTnT. After adjustment for baseline clinical characteristics, the association between an elevated cTnT level and increased incidence of all-cause mortality (adjusted hazard ratio, 1.9; 95% CI, 1.1-3.1) persisted. Elevated cTnT had significant prognostic value in patients with and without renal dysfunction, abnormal levels of CK-MB, and in patients with transient ECG abnormalities. Elevated cTnT levels are associated with an increased incidence of all-cause mortality in patients undergoing major vascular surgery.
    European Journal of Vascular and Endovascular Surgery 07/2004; 28(1):59-66. DOI:10.1016/j.ejvs.2004.02.026 · 3.07 Impact Factor
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    ABSTRACT: We report the pre-operative preparation and anaesthetic management for resection of an intracerebral tumour during awake craniotomy in a 9-year-old boy. We believe this is the youngest patient reported to have undergone this procedure. The challenges of sedation and psychological care throughout the procedure are discussed. We conclude that the procedure can be performed safely and that it seems unacceptable to uphold an age restriction. We believe that it is the individual level of development of the child that determines suitability for this type of surgery.
    Anaesthesia 07/2004; 59(6):607-9. DOI:10.1111/j.1365-2044.2004.03675.x · 3.85 Impact Factor

Publication Stats

571 Citations
81.86 Total Impact Points

Institutions

  • 2004–2011
    • Erasmus MC
      • • Department of Anesthesiology
      • • Department of Cardiology
      Rotterdam, South Holland, Netherlands
  • 2000–2011
    • Erasmus Universiteit Rotterdam
      • • Institute of Health Policy & Management (iBMG)
      • • Department of Anesthesiology
      • • Department of Cardiology
      Rotterdam, South Holland, Netherlands
  • 2007
    • Radboud University Nijmegen
      Nymegen, Gelderland, Netherlands