Cor Kalkman - Academia.edu (original) (raw)
Papers by Cor Kalkman
International Journal of Nursing Studies, 2015
Journal of clinical epidemiology, Jan 15, 2015
To design and validate a practical questionnaire for clinicians, to identify barriers and facilit... more To design and validate a practical questionnaire for clinicians, to identify barriers and facilitators for Evidence Based Practice (EBP), i.e. the use of research evidence in patient care. The inventory is ultimately intended for departments to assess local conditions for EBP, to aim and evaluate efforts at improving or maximizing EBP. We derived candidate items from existing EBP scales, psychology and behavioural economics. In an online Delphi study, 537 international expert clinicians, researchers, teachers and policymakers interested in EBP identified items with sufficient face and content validity. We piloted and validated the resulting draft Inventory among 127 clinicians from various specialties and career stages. The Delphi study started with 114 items and resulted in a draft Inventory with 29 items in 5 dimensions. During the pilot the inventory was easy to complete within 15 minutes and the items showed sufficient response variation. In 4 of 5 dimensions test-retest reliabi...
Anesthesia and analgesia, 2014
Methylprednisolone acetate (MPA) has a long history of use in the treatment of sciatic pain and o... more Methylprednisolone acetate (MPA) has a long history of use in the treatment of sciatic pain and other neuropathic pain syndromes. In several of these syndromes, MPA is administered in the epidural space. On a limited basis, MPA has also been injected intrathecally in patients suffering from postherpetic neuralgia and complex regional pain syndrome. The reports on efficacy of intrathecal administration of MPA in neuropathic pain patients are contradictory, and safety is debated. In this review, we broadly consider mechanisms whereby glucocorticoids exert their action on spinal cascades relevant to the pain arising after nerve injury and inflammation. We then focus on the characteristics of the actions of MPA in pharmacokinetics, efficacy, and safety when administered in the intrathecal space.
Heart (British Cardiac Society), 2004
To describe the association between cognitive outcome in the first postoperative week and that at... more To describe the association between cognitive outcome in the first postoperative week and that at three months after both off-pump and on-pump coronary bypass surgery, and to make a direct comparison of early cognitive outcome after off-pump versus on-pump surgery. Randomised trial with an additional prediction study within the two randomised groups. Three centres for heart surgery in the Netherlands. 281 patients, mean age 61 years. Participants were randomly assigned to off-pump or on-pump coronary bypass surgery. Cognitive outcome, assessed by psychologists who administered neuropsychological tests one day before and four days and three months after surgery. A logistic regression model was used to study the predictive association between early cognitive outcome, together with eight clinical variables, and cognitive outcome after three months. Cognitive outcome in the first week after surgery was determined for 219 patients and was a predictor of cognitive decline after three mont...
Nederlands tijdschrift voor geneeskunde, 2013
Many experimental studies in mammals, and increasingly also in primates, have shown that almost a... more Many experimental studies in mammals, and increasingly also in primates, have shown that almost all anaesthetic agents when administered during a young animal's brain-development phase cause increased neuroapoptosis and changes in dendritic morphology at short term, and later, learning disorders. These findings are being confirmed in increasing numbers of retrospective cohort studies in humans. However, these retrospective cohort studies are considerably influenced by confounding. A current prospective randomized clinical trial comparing general and locoregional (spinal) anaesthesia for hernia repair could provide some clinical evidence. These study results will only provide information on relatively short procedures and will not be available until the first reliable neuropsychological evaluation at age 5 in 2018. Pending this additional data, we should discuss with our surgical colleagues the indications, timing and duration of surgery and - if possible - postpone elective surg...
European journal of cardiovascular nursing : journal of the Working Group on Cardiovascular Nursing of the European Society of Cardiology, 2014
In older patients undergoing elective cardiac surgery, the timely identification and preparation ... more In older patients undergoing elective cardiac surgery, the timely identification and preparation of patients at risk for frequent postoperative hospital complications provide opportunities to reduce the risk of these complications. We developed an evidence-based, multi-component nursing intervention (Prevention of Decline in Older Cardiac Surgery Patients; the PREDOCS programme) for application in the preadmission period to improve patients' physical and psychosocial condition to reduce their risk of postoperative complications. This paper describes in detail the process used to design and develop this multi-component intervention. In a team of researchers, experts, cardiac surgeons, registered cardiac surgery nurses, and patients, the revised guidelines for developing and evaluating complex interventions of the Medical Research Council (MRC) were followed, including identifying existing evidence, identifying and developing theory and modelling the process and outcomes. Addition...
Advances in Experimental Medicine and Biology, 2003
Neurocognitive decline following cardiac surgery is an increasing problem, particularly affecting... more Neurocognitive decline following cardiac surgery is an increasing problem, particularly affecting older patients. The use of cardiopulmonary bypass is a suspected cause. Research into pathophysiology and possible preventive measures requires the use of an animal model. Commercial oxygenators are too large and expensive for use in small animals. We describe a fiber oxygenator scaled for use in the rat. In vitro and in vivo testing show that it is able to support full gas exchange in this size of animal, and causes no allergic or toxic reactions.
ABSTRACT To study the effect of intraoperative hypotension on the occurrence of stroke following ... more ABSTRACT To study the effect of intraoperative hypotension on the occurrence of stroke following non-cardiac and non-neurosurgical procedures. Nested patient-control study. From January 2002-June 2009, all patients at UMC Utrecht who had a stroke within 10 days of undergoing a non-cardiac or non-neurosurgical procedure were matched with 6 control patients of the same age who underwent the same procedure but had no stroke. A total of 42 patients who suffered postoperative stroke (0.09%) were included. After correction for potential confounders, the length of time that the mean blood pressure remained more than 30% lower than baseline was statistically significantly associated with the occurrence of a postoperative stroke. Intraoperative hypotension may play a role in the development of postoperative ischaemic stroke.
Seminars in Thoracic and Cardiovascular Surgery, 1998
Spinal cord ischemia during resection of thoracoabdominal aortic aneurysms (TAA) can result in lo... more Spinal cord ischemia during resection of thoracoabdominal aortic aneurysms (TAA) can result in lower limb neurological deficits. Spinal cord monitoring can only improve outcome if ischemia is detected before irreversible damage has occurred and protective measures are readily available. Monitorin( spinal cord function with motor evoked potentials (MEPs) is a relatively new technique. With MEP. recorded from the muscle (myogenic MEPs), the vulnerable spinal motoneuronal system is exclusively monitored and ischemia is detected within minutes. Using a strategy aimed at maintaining and restoring spinal cord blood supply (distal aortic perfusion, sequential aortic clamping, and selective segmental artery reattachment), early detection of ischemia allows protective measures to be applied and adjusted immediately, ie, reattaching or safely ligating intercostal arteries, increasing proximal o distal aortic pressures as required, or inducing hypothermia. Recent improvements in the technique fo eliciting myogenic MEPs include multi-pulse stimulation paradigms and the use of a circumferentia cathode. This results in robust and reproducible signals, which are less susceptible to anesthetic interference and allow the use of a constant level of neuromuscular blockade. In conclusion, monitoring myogenic MEPs during a TAA repair has become clinically feasible. The fast detection of spinal cord ischemia allows timely guidance of protective measures.
BMC Health Serv Res, 2014
Deliberate hyperthermia has been used clinically as experimental therapy for neoplastic and infec... more Deliberate hyperthermia has been used clinically as experimental therapy for neoplastic and infectious diseases. Several case fatalities have occurred with this form of treatment, but most were attributable to systemic complications rather than central nervous system toxicity. Nonetheless, demyelating peripheral neuropathy and neurological symptoms of nausea, delirium, apathy, stupor, and coma have been reported. Temperatures exceeding 40 degrees C cause transient vasoparalysis in humans, resulting in cerebral metabolic uncoupling and loss of pressure-flow autoregulation. These findings may be related to the development of brain edema, intracerebral hemorrhage, and intracranial hypertension observed after prolonged therapeutic hyperthermia. Furthermore, deliberate hyperthermia critically worsens the extent of histopathological damage in animal models of traumatic, ischemic, and hypoxic brain injury. However, it is unknown whether these findings translate to episodes of spontaneous fever in neurologically injured patients. In a clinical setting fever is a strong prognostic marker of a patient's primary degree of neuronal damage, and a causal relation with long-term functional neurological outcome has not been established for most types of brain injury. Furthermore, in the neurosurgical intensive-care unit fever is extremely common whereas antipyretic therapy is only poorly effective. Therefore maintaining strict normothermia may be an impossible goal in many patients. Although there are several physiological arguments for avoiding exogenous hyperthermia in neurologically injured patients, there is no evidence that aggressive attempts at controlling spontaneous fever can improve clinical outcome.
Reviews, 1996
High-dose prophylactic corticosteroids are often administered during cardiac surgery. Their use, ... more High-dose prophylactic corticosteroids are often administered during cardiac surgery. Their use, however, remains controversial, as no trials are available that have been sufficiently powered to draw conclusions on their effect on major clinical outcomes. The objective of this meta-analysis was to estimate the effect of prophylactic corticosteroids in cardiac surgery on mortality, cardiac and pulmonary complications. Major medical databases (CENTRAL, MEDLINE, EMBASE, CINAHL and Web of Science) were systematically searched for randomised studies assessing the effect of corticosteroids in adult cardiac surgery. Database were searched for the full period covered, up to December 2009. No language restrictions were applied. Randomised controlled trials comparing corticosteroid treatment to either placebo treatment or no treatment in adult cardiac surgery were selected. There were no restrictions with respect to length of the follow-up period. All selected studies qualified for pooling of results for one or more end-points. The processes of searching and selection for inclusion eligibility were performed independently by two authors. Also, quality assessment and data-extraction of selected studies were independently performed by two authors. The primary endpoints were mortality, cardiac and pulmonary complications. The main effect measure was the Peto odds ratio comparing corticosteroids to no treatment/placebo. Fifty-four randomised studies, mostly of limited quality, were included. Altogether, 3615 patients were included in these studies. The pooled odds ratio for mortality was 1.12 (95% CI 0.65 to 1.92), showing no mortality reduction in patients treated with corticosteroids. The odds ratios for myocardial and pulmonary complications were 0.95, (95% CI 0.57 to 1.60) and 0.83 (95% CI 0.49 to 1.40), respectively. The use of a random effects model did not substantially influence study results. Analyses of secondary endpoints showed a reduction of atrial fibrillation and an increase in gastrointestinal bleeding in the corticosteroids group. This meta-analysis showed no beneficial effect of corticosteroid use on mortality, cardiac and pulmonary complications in cardiac surgery patients.
Survey of Anesthesiology, 2014
International Journal of Nursing Studies, 2015
Journal of clinical epidemiology, Jan 15, 2015
To design and validate a practical questionnaire for clinicians, to identify barriers and facilit... more To design and validate a practical questionnaire for clinicians, to identify barriers and facilitators for Evidence Based Practice (EBP), i.e. the use of research evidence in patient care. The inventory is ultimately intended for departments to assess local conditions for EBP, to aim and evaluate efforts at improving or maximizing EBP. We derived candidate items from existing EBP scales, psychology and behavioural economics. In an online Delphi study, 537 international expert clinicians, researchers, teachers and policymakers interested in EBP identified items with sufficient face and content validity. We piloted and validated the resulting draft Inventory among 127 clinicians from various specialties and career stages. The Delphi study started with 114 items and resulted in a draft Inventory with 29 items in 5 dimensions. During the pilot the inventory was easy to complete within 15 minutes and the items showed sufficient response variation. In 4 of 5 dimensions test-retest reliabi...
Anesthesia and analgesia, 2014
Methylprednisolone acetate (MPA) has a long history of use in the treatment of sciatic pain and o... more Methylprednisolone acetate (MPA) has a long history of use in the treatment of sciatic pain and other neuropathic pain syndromes. In several of these syndromes, MPA is administered in the epidural space. On a limited basis, MPA has also been injected intrathecally in patients suffering from postherpetic neuralgia and complex regional pain syndrome. The reports on efficacy of intrathecal administration of MPA in neuropathic pain patients are contradictory, and safety is debated. In this review, we broadly consider mechanisms whereby glucocorticoids exert their action on spinal cascades relevant to the pain arising after nerve injury and inflammation. We then focus on the characteristics of the actions of MPA in pharmacokinetics, efficacy, and safety when administered in the intrathecal space.
Heart (British Cardiac Society), 2004
To describe the association between cognitive outcome in the first postoperative week and that at... more To describe the association between cognitive outcome in the first postoperative week and that at three months after both off-pump and on-pump coronary bypass surgery, and to make a direct comparison of early cognitive outcome after off-pump versus on-pump surgery. Randomised trial with an additional prediction study within the two randomised groups. Three centres for heart surgery in the Netherlands. 281 patients, mean age 61 years. Participants were randomly assigned to off-pump or on-pump coronary bypass surgery. Cognitive outcome, assessed by psychologists who administered neuropsychological tests one day before and four days and three months after surgery. A logistic regression model was used to study the predictive association between early cognitive outcome, together with eight clinical variables, and cognitive outcome after three months. Cognitive outcome in the first week after surgery was determined for 219 patients and was a predictor of cognitive decline after three mont...
Nederlands tijdschrift voor geneeskunde, 2013
Many experimental studies in mammals, and increasingly also in primates, have shown that almost a... more Many experimental studies in mammals, and increasingly also in primates, have shown that almost all anaesthetic agents when administered during a young animal's brain-development phase cause increased neuroapoptosis and changes in dendritic morphology at short term, and later, learning disorders. These findings are being confirmed in increasing numbers of retrospective cohort studies in humans. However, these retrospective cohort studies are considerably influenced by confounding. A current prospective randomized clinical trial comparing general and locoregional (spinal) anaesthesia for hernia repair could provide some clinical evidence. These study results will only provide information on relatively short procedures and will not be available until the first reliable neuropsychological evaluation at age 5 in 2018. Pending this additional data, we should discuss with our surgical colleagues the indications, timing and duration of surgery and - if possible - postpone elective surg...
European journal of cardiovascular nursing : journal of the Working Group on Cardiovascular Nursing of the European Society of Cardiology, 2014
In older patients undergoing elective cardiac surgery, the timely identification and preparation ... more In older patients undergoing elective cardiac surgery, the timely identification and preparation of patients at risk for frequent postoperative hospital complications provide opportunities to reduce the risk of these complications. We developed an evidence-based, multi-component nursing intervention (Prevention of Decline in Older Cardiac Surgery Patients; the PREDOCS programme) for application in the preadmission period to improve patients' physical and psychosocial condition to reduce their risk of postoperative complications. This paper describes in detail the process used to design and develop this multi-component intervention. In a team of researchers, experts, cardiac surgeons, registered cardiac surgery nurses, and patients, the revised guidelines for developing and evaluating complex interventions of the Medical Research Council (MRC) were followed, including identifying existing evidence, identifying and developing theory and modelling the process and outcomes. Addition...
Advances in Experimental Medicine and Biology, 2003
Neurocognitive decline following cardiac surgery is an increasing problem, particularly affecting... more Neurocognitive decline following cardiac surgery is an increasing problem, particularly affecting older patients. The use of cardiopulmonary bypass is a suspected cause. Research into pathophysiology and possible preventive measures requires the use of an animal model. Commercial oxygenators are too large and expensive for use in small animals. We describe a fiber oxygenator scaled for use in the rat. In vitro and in vivo testing show that it is able to support full gas exchange in this size of animal, and causes no allergic or toxic reactions.
ABSTRACT To study the effect of intraoperative hypotension on the occurrence of stroke following ... more ABSTRACT To study the effect of intraoperative hypotension on the occurrence of stroke following non-cardiac and non-neurosurgical procedures. Nested patient-control study. From January 2002-June 2009, all patients at UMC Utrecht who had a stroke within 10 days of undergoing a non-cardiac or non-neurosurgical procedure were matched with 6 control patients of the same age who underwent the same procedure but had no stroke. A total of 42 patients who suffered postoperative stroke (0.09%) were included. After correction for potential confounders, the length of time that the mean blood pressure remained more than 30% lower than baseline was statistically significantly associated with the occurrence of a postoperative stroke. Intraoperative hypotension may play a role in the development of postoperative ischaemic stroke.
Seminars in Thoracic and Cardiovascular Surgery, 1998
Spinal cord ischemia during resection of thoracoabdominal aortic aneurysms (TAA) can result in lo... more Spinal cord ischemia during resection of thoracoabdominal aortic aneurysms (TAA) can result in lower limb neurological deficits. Spinal cord monitoring can only improve outcome if ischemia is detected before irreversible damage has occurred and protective measures are readily available. Monitorin( spinal cord function with motor evoked potentials (MEPs) is a relatively new technique. With MEP. recorded from the muscle (myogenic MEPs), the vulnerable spinal motoneuronal system is exclusively monitored and ischemia is detected within minutes. Using a strategy aimed at maintaining and restoring spinal cord blood supply (distal aortic perfusion, sequential aortic clamping, and selective segmental artery reattachment), early detection of ischemia allows protective measures to be applied and adjusted immediately, ie, reattaching or safely ligating intercostal arteries, increasing proximal o distal aortic pressures as required, or inducing hypothermia. Recent improvements in the technique fo eliciting myogenic MEPs include multi-pulse stimulation paradigms and the use of a circumferentia cathode. This results in robust and reproducible signals, which are less susceptible to anesthetic interference and allow the use of a constant level of neuromuscular blockade. In conclusion, monitoring myogenic MEPs during a TAA repair has become clinically feasible. The fast detection of spinal cord ischemia allows timely guidance of protective measures.
BMC Health Serv Res, 2014
Deliberate hyperthermia has been used clinically as experimental therapy for neoplastic and infec... more Deliberate hyperthermia has been used clinically as experimental therapy for neoplastic and infectious diseases. Several case fatalities have occurred with this form of treatment, but most were attributable to systemic complications rather than central nervous system toxicity. Nonetheless, demyelating peripheral neuropathy and neurological symptoms of nausea, delirium, apathy, stupor, and coma have been reported. Temperatures exceeding 40 degrees C cause transient vasoparalysis in humans, resulting in cerebral metabolic uncoupling and loss of pressure-flow autoregulation. These findings may be related to the development of brain edema, intracerebral hemorrhage, and intracranial hypertension observed after prolonged therapeutic hyperthermia. Furthermore, deliberate hyperthermia critically worsens the extent of histopathological damage in animal models of traumatic, ischemic, and hypoxic brain injury. However, it is unknown whether these findings translate to episodes of spontaneous fever in neurologically injured patients. In a clinical setting fever is a strong prognostic marker of a patient's primary degree of neuronal damage, and a causal relation with long-term functional neurological outcome has not been established for most types of brain injury. Furthermore, in the neurosurgical intensive-care unit fever is extremely common whereas antipyretic therapy is only poorly effective. Therefore maintaining strict normothermia may be an impossible goal in many patients. Although there are several physiological arguments for avoiding exogenous hyperthermia in neurologically injured patients, there is no evidence that aggressive attempts at controlling spontaneous fever can improve clinical outcome.
Reviews, 1996
High-dose prophylactic corticosteroids are often administered during cardiac surgery. Their use, ... more High-dose prophylactic corticosteroids are often administered during cardiac surgery. Their use, however, remains controversial, as no trials are available that have been sufficiently powered to draw conclusions on their effect on major clinical outcomes. The objective of this meta-analysis was to estimate the effect of prophylactic corticosteroids in cardiac surgery on mortality, cardiac and pulmonary complications. Major medical databases (CENTRAL, MEDLINE, EMBASE, CINAHL and Web of Science) were systematically searched for randomised studies assessing the effect of corticosteroids in adult cardiac surgery. Database were searched for the full period covered, up to December 2009. No language restrictions were applied. Randomised controlled trials comparing corticosteroid treatment to either placebo treatment or no treatment in adult cardiac surgery were selected. There were no restrictions with respect to length of the follow-up period. All selected studies qualified for pooling of results for one or more end-points. The processes of searching and selection for inclusion eligibility were performed independently by two authors. Also, quality assessment and data-extraction of selected studies were independently performed by two authors. The primary endpoints were mortality, cardiac and pulmonary complications. The main effect measure was the Peto odds ratio comparing corticosteroids to no treatment/placebo. Fifty-four randomised studies, mostly of limited quality, were included. Altogether, 3615 patients were included in these studies. The pooled odds ratio for mortality was 1.12 (95% CI 0.65 to 1.92), showing no mortality reduction in patients treated with corticosteroids. The odds ratios for myocardial and pulmonary complications were 0.95, (95% CI 0.57 to 1.60) and 0.83 (95% CI 0.49 to 1.40), respectively. The use of a random effects model did not substantially influence study results. Analyses of secondary endpoints showed a reduction of atrial fibrillation and an increase in gastrointestinal bleeding in the corticosteroids group. This meta-analysis showed no beneficial effect of corticosteroid use on mortality, cardiac and pulmonary complications in cardiac surgery patients.
Survey of Anesthesiology, 2014