michael felfernig - Academia.edu (original) (raw)
Papers by michael felfernig
Journal of The Royal Naval Medical Service, 2006
Ketamine is a strong acting analgesic drug, used mainly in trauma and emergency medicine settings... more Ketamine is a strong acting analgesic drug, used mainly in trauma and emergency medicine settings, as well as for minor procedures. Its pharmacological properties make it a useful drug for military anaesthesia. Ketamine acts by blocking activation of the spinal and supraspinal NMDA-type glutamate and opioid receptors. It produces dissociative anaesthesia, which means that patients might remain conscious, though insensitive to pain and amnesic (anterograde), Dysphoria and hallucinations are the main side effects in the early recovery period. We studied the incidence of post operative nausea and vomiting, vigilance disturbances and haemodynamic instability during combined ketamine and propofol anaesthesia.No patient suffered from postoperative nausea and vomiting. No haemodynamic instabilily could be observed in any of the patients. Tie interesting point is that though there were no unpleasant emergence phenomenons, no patient reached the preoperative state of vigilance within two hou...
Anesthesia and Analgesia, 2008
SPE Nigeria Annual International Conference and Exhibition, 2014
Background: Internationally, Cardiovascular diseases (CVD) constitute a major cause of morbidity ... more Background: Internationally, Cardiovascular diseases (CVD) constitute a major cause of morbidity and mortality and it is estimated that by 2020 a majority of the global burden of CVD will be in developing countries. Offshore workers are often more prone to CVD due to unhealthy lifestyles however, the risk of CVD to this population is largely unknown in sub-Saharan Africa. Our study determined the prevalence of modifiable cardiovascular risk factors among off-shore workers in Nigeria. Methodology A descriptive cross-sectional study was carried out amongst male off-shore workers in the Niger delta area of Nigeria from January to December 2012. Participants of the study were recruited consecutively during periodic medical fitness for work examinations where sociodemographic data, anthropometric measurements and blood pressure were obtained in a standardized manner.Venous blood samples were collected in the fasting state for glucose and lipid profile including total cholesterol, triglyc...
International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production, 2012
Following detection of two open tuberculosis (TB) cases among offshore installation workers some ... more Following detection of two open tuberculosis (TB) cases among offshore installation workers some years ago, screening for latent TB infection using an interferon gamma release assay, QuantiFERON-TB Gold test (QTBGT), was introduced in the oil industry. Since the introduction of QTBGT, this screening has been used as a prerequisite for working offshore with focus on TB diagnosis (active and latent) and monitoring of clinical management. The aim of our retrospective descriptive study was to determine the prevalence of patients with latent or active TB in offshore workers in Nigeria. Methods. We used medical records in order to gather all demographic and medical data of patients who underwent QuantiFERON-TB Gold test (QFT-G Cellestis Limited, Carnegie, Victoria, Australia) within a period of 40 month in our facility. Ages, gender, country of origin and test results of the QTBGT were documented. We furthermore evaluated the findings of chest x rays, and compared findings by age and regi...
Thrombosis Research, 2001
This prospective randomized study investigated the influence of normotensive and hypotensive gene... more This prospective randomized study investigated the influence of normotensive and hypotensive general anesthesia on platelet aggregability, intraoperative blood loss and parameters of plasmatic coagulation during extensive orthognathic surgery. A total of 30 patients were randomly allocated for either normotensive anesthesia maintained by continuous infusion of propofol and remifentanil (NORMO, n=10) or hypotensive anesthesia, whereby hypotension was induced by increasing the infusion rate of remifentanil (HYPO-R, n=10) or by administration of nitroglycerin (HYPO-N, n=10). Whole blood platelet aggregability was significantly reduced during hypotension compared to normotensive anesthesia (P<.01, HYPO-N and HYPO-R vs. NORMO). Mean arterial blood pressure during hypotension correlated well with adenosinediphosphate- (R=.712, P<.001) and collagen-induced platelet aggregability (R=.685, P<.001). Within hypotensive study groups, postoperative fibrinogen levels were significantly different, whereas intraoperative platelet aggregability, postoperative platelet count, prothrombin time, activated partial thromboplastin time and antithrombin levels were not different. Normotensive anesthesia, however, caused significant decreases in platelet count (-29%), prothrombin time (-24%), fibrinogen (-41%) and antithrombin (-28%) and a significant prolongation in activated partial thromboplastin time (+21%) and thrombin time (+18%). There was a trend to reduced intraoperative blood loss in hypotensive study groups; however, differences were not significant. In conclusion, induced hypotension--independent of substances used for induction of hypotension--reduces intraoperative platelet aggregability, subsequently protecting the coagulation system against subclinical consumption coagulopathy. Induced hypotension-caused platelet dysfunction does not lead to an increased intraoperative blood loss, but quite on the contrary shows a trend to reduced intraoperative blood loss, possibly by preventing platelet-induced subclinical consumption coagulopathy.
European Journal of Anaesthesiology, 2008
To investigate whether preemptive administered lornoxicam changes perioperative platelet function... more To investigate whether preemptive administered lornoxicam changes perioperative platelet function during thoracic surgery. A total of 20 patients scheduled for elective thoracic surgery were randomly assigned to receive either lornoxicam (16 mg, i.v.; n = 10) or placebo (n = 10) preoperatively. All patients underwent treatment of solitary lung metastasis and denied any antiplatelet medication within the past 2 weeks. Blood samples were drawn via an arterial catheter directly into silicone-coated Vacutainer tubes containing 0.5 mL of 0.129 M buffered sodium citrate 3.8% before, 15 min, 4 h and 8 h after the study medication was administered. Platelet aggregation curves were obtained by whole blood electrical impedance aggregometry (Chrono Log). Platelet aggregation was significantly reduced 15 min, 4 h and 8 h after lornoxicam administration compared to placebo (P < 0.05) for collagen, adenosine diphosphate and arachidonic acid as trigger substances. Adenosine diphosphate-induced platelet aggregation decreased by 85% 15 min after lornoxicam administration, and remained impaired for 8 h. Platelet aggregation assays are impaired for at least 8 h after lornoxicam application. Therefore perioperative analgesia by use of lornoxicam should be carefully administered under consideration of subsequent platelet dysfunction.
Critical Care Medicine, 1994
Anesthesia & Analgesia, 2000
Endotracheal intubation has been performed during the administration of propofol anesthesia witho... more Endotracheal intubation has been performed during the administration of propofol anesthesia without neuromuscular blockade. In this study, we determined the propofol dose required for conventional nasotracheal or for fiberoptic nasotracheal intubation of all patients. Thirty-two patients undergoing maxillofacial surgery were randomly assigned to the conventional (n = 16) or to the fiberoptic (n = 16) intubation group. In both groups, anesthesia was induced by using IV fentanyl and IV titrated propofol according to clinical need (spontaneous respiration rate, verbal response). An endotracheal tube was placed nasally in the pharynx and the vocal cords visualized by using a fiberscope inserted via the tube. In the conventional group, the larynx was visualized additionally with a laryngoscope blade (Miller). In both groups propofol was titrated until the vocal cords opened. Patients were tracheally intubated, and the propofol dose was recorded. In all patients, the trachea could be intubated without the use of muscle relaxants. Considerable interindividual differences of dose requirements were observed. The amount of propofol required in the conventional group was significantly (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.0001) larger (median +/- SD: 2.74 +/- 1.59 mg/kg; range 1.95-7.07 mg/kg) than in the fiberoptic group (1.37 +/- 0.59 mg/kg; 0.72-2.86 mg/kg). Hemodynamics remained stable in all patients. Postintubational hoarseness occurred in three patients of each group. Fiberoptic nasal intubation without a muscle relaxant can be facilitated with significantly smaller and more predictable dosages of propofol than conventional nasal endotracheal intubation. The possibility of titrating the propofol dose under assisted ventilation until the vocal cords open during fiberoptic nasotracheal intubation and the better predictability of the required dose favors the fiberoptic approach. In this study, contrary to all preceding studies using predefined doses of propofol and opioids, we determined the minimal required propofol dose in combination with fentanyl for conventional or fiberoptic nasotracheal intubation without muscle relaxants.
Anesthesia & Analgesia, 2008
Ultrasonographic observation of peripheral nerve blocks enables direct visualization of the sprea... more Ultrasonographic observation of peripheral nerve blocks enables direct visualization of the spread of local anesthetic around the targeted nerves. Similarly, ultrasonography may be used to determine the site of local anesthetic placement when landmark-based techniques are used. We performed a study to determine the actual location of local anesthetic when ilioinguinal/iliohypogastric nerve blocks are performed using landmark-based techniques in children in an attempt to explain a failed block. After induction of general anesthesia (1 minimum alveolar anesthetic concentration halothane and laryngeal mask airway), 62 children scheduled for inguinal surgery received an ilioinguinal/iliohypogastric nerve block based on standard anatomical landmarks. Ultrasonography was then used to determine the actual location of local anesthetic placement. The anesthesiologist performing the block was blinded to the ultrasonographic investigation. Successful blocks were recorded either when the local anesthetic surrounded the nerves or were based on clinical signs after skin incision. In 14% of the blocks, the local anesthetic was administered correctly around the nerves resulting in successful blocks. In the remaining 86%, the local anesthetic was administered in adjacent anatomical structures (iliac muscle 18%, transverse abdominal muscle 26%, internal oblique abdominal muscle 29%, external oblique abdominal muscle 9%, subcutaneous 2%, and peritoneum 2%), and 45% of these blocks failed. Accurate placement of local anesthetic around the ilioinguinal/iliohypogastric nerves in children is seldom possible when landmark-based techniques are used. In the majority of patients, the local anesthetic was inaccurately placed in adjacent anatomical structures with unpredictable block results.
Burns, 1999
In severely burned patients the approach to the central vein is often dicult due to concomitant e... more In severely burned patients the approach to the central vein is often dicult due to concomitant edema, but also due to the fact that the skin area, where commonly used approaches are performed, is burned as well, whereas the axillary region is often not involved. In order to perform an axillary approach to the central vein as an alternative to the commonly used approaches in patients, an anatomical dissection in fresh human cadavers was carried out. Considering the anatomical landmarks which were found during dissection of the axillary region, the axillary approach to the central vein was used in 35 patients in our intensive burn care unit with unaected axillary skin. In three cases the only complication observed was an occasional puncture of the axillary artery without major hematoma. The infection rate of the catheters was similar to the commonly used puncture sites. This approach to the central venous line in severely burned patients can be recommended.
Anesthesiology, 1998
Wolters Kluwer Health may email you for journal alerts and information, but is committed to maint... more Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your privacy and will not share your personal information without your express consent. For more information, please refer to our Privacy Policy. ... An abstract is unavailable. This article is ...
Acta anaesthesiologica Scandinavica. Supplementum
... Physiologyc basis of a bedside screening test. JAMA 1966: 196: 754-756. 15. Tapson VF,Witty L... more ... Physiologyc basis of a bedside screening test. JAMA 1966: 196: 754-756. 15. Tapson VF,Witty LA. Massive pulmonary embolism. Diag-nostic and therapeutic strategies. Clin Chest Med 1995: 16 16. Sdunid C, Zietlow S, Wagner TO, Laas J, Borst HG. ...
Infusionstherapie und Transfusionsmedizin
ABSTRACT
Background. Recent studies have shown that ultrasound guidance for paediatric regional anaesthesi... more Background. Recent studies have shown that ultrasound guidance for paediatric regional anaesthesia can improve the quality of upper extremity and neuraxial blocks. We therefore investigated whether ultrasound guidance for sciatic and femoral nerve blocks prolongs sensory blockade in comparison with nerve stimulator guidance in children.
Journal of The Royal Naval Medical Service, 2006
Ketamine is a strong acting analgesic drug, used mainly in trauma and emergency medicine settings... more Ketamine is a strong acting analgesic drug, used mainly in trauma and emergency medicine settings, as well as for minor procedures. Its pharmacological properties make it a useful drug for military anaesthesia. Ketamine acts by blocking activation of the spinal and supraspinal NMDA-type glutamate and opioid receptors. It produces dissociative anaesthesia, which means that patients might remain conscious, though insensitive to pain and amnesic (anterograde), Dysphoria and hallucinations are the main side effects in the early recovery period. We studied the incidence of post operative nausea and vomiting, vigilance disturbances and haemodynamic instability during combined ketamine and propofol anaesthesia.No patient suffered from postoperative nausea and vomiting. No haemodynamic instabilily could be observed in any of the patients. Tie interesting point is that though there were no unpleasant emergence phenomenons, no patient reached the preoperative state of vigilance within two hou...
Anesthesia and Analgesia, 2008
SPE Nigeria Annual International Conference and Exhibition, 2014
Background: Internationally, Cardiovascular diseases (CVD) constitute a major cause of morbidity ... more Background: Internationally, Cardiovascular diseases (CVD) constitute a major cause of morbidity and mortality and it is estimated that by 2020 a majority of the global burden of CVD will be in developing countries. Offshore workers are often more prone to CVD due to unhealthy lifestyles however, the risk of CVD to this population is largely unknown in sub-Saharan Africa. Our study determined the prevalence of modifiable cardiovascular risk factors among off-shore workers in Nigeria. Methodology A descriptive cross-sectional study was carried out amongst male off-shore workers in the Niger delta area of Nigeria from January to December 2012. Participants of the study were recruited consecutively during periodic medical fitness for work examinations where sociodemographic data, anthropometric measurements and blood pressure were obtained in a standardized manner.Venous blood samples were collected in the fasting state for glucose and lipid profile including total cholesterol, triglyc...
International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production, 2012
Following detection of two open tuberculosis (TB) cases among offshore installation workers some ... more Following detection of two open tuberculosis (TB) cases among offshore installation workers some years ago, screening for latent TB infection using an interferon gamma release assay, QuantiFERON-TB Gold test (QTBGT), was introduced in the oil industry. Since the introduction of QTBGT, this screening has been used as a prerequisite for working offshore with focus on TB diagnosis (active and latent) and monitoring of clinical management. The aim of our retrospective descriptive study was to determine the prevalence of patients with latent or active TB in offshore workers in Nigeria. Methods. We used medical records in order to gather all demographic and medical data of patients who underwent QuantiFERON-TB Gold test (QFT-G Cellestis Limited, Carnegie, Victoria, Australia) within a period of 40 month in our facility. Ages, gender, country of origin and test results of the QTBGT were documented. We furthermore evaluated the findings of chest x rays, and compared findings by age and regi...
Thrombosis Research, 2001
This prospective randomized study investigated the influence of normotensive and hypotensive gene... more This prospective randomized study investigated the influence of normotensive and hypotensive general anesthesia on platelet aggregability, intraoperative blood loss and parameters of plasmatic coagulation during extensive orthognathic surgery. A total of 30 patients were randomly allocated for either normotensive anesthesia maintained by continuous infusion of propofol and remifentanil (NORMO, n=10) or hypotensive anesthesia, whereby hypotension was induced by increasing the infusion rate of remifentanil (HYPO-R, n=10) or by administration of nitroglycerin (HYPO-N, n=10). Whole blood platelet aggregability was significantly reduced during hypotension compared to normotensive anesthesia (P<.01, HYPO-N and HYPO-R vs. NORMO). Mean arterial blood pressure during hypotension correlated well with adenosinediphosphate- (R=.712, P<.001) and collagen-induced platelet aggregability (R=.685, P<.001). Within hypotensive study groups, postoperative fibrinogen levels were significantly different, whereas intraoperative platelet aggregability, postoperative platelet count, prothrombin time, activated partial thromboplastin time and antithrombin levels were not different. Normotensive anesthesia, however, caused significant decreases in platelet count (-29%), prothrombin time (-24%), fibrinogen (-41%) and antithrombin (-28%) and a significant prolongation in activated partial thromboplastin time (+21%) and thrombin time (+18%). There was a trend to reduced intraoperative blood loss in hypotensive study groups; however, differences were not significant. In conclusion, induced hypotension--independent of substances used for induction of hypotension--reduces intraoperative platelet aggregability, subsequently protecting the coagulation system against subclinical consumption coagulopathy. Induced hypotension-caused platelet dysfunction does not lead to an increased intraoperative blood loss, but quite on the contrary shows a trend to reduced intraoperative blood loss, possibly by preventing platelet-induced subclinical consumption coagulopathy.
European Journal of Anaesthesiology, 2008
To investigate whether preemptive administered lornoxicam changes perioperative platelet function... more To investigate whether preemptive administered lornoxicam changes perioperative platelet function during thoracic surgery. A total of 20 patients scheduled for elective thoracic surgery were randomly assigned to receive either lornoxicam (16 mg, i.v.; n = 10) or placebo (n = 10) preoperatively. All patients underwent treatment of solitary lung metastasis and denied any antiplatelet medication within the past 2 weeks. Blood samples were drawn via an arterial catheter directly into silicone-coated Vacutainer tubes containing 0.5 mL of 0.129 M buffered sodium citrate 3.8% before, 15 min, 4 h and 8 h after the study medication was administered. Platelet aggregation curves were obtained by whole blood electrical impedance aggregometry (Chrono Log). Platelet aggregation was significantly reduced 15 min, 4 h and 8 h after lornoxicam administration compared to placebo (P < 0.05) for collagen, adenosine diphosphate and arachidonic acid as trigger substances. Adenosine diphosphate-induced platelet aggregation decreased by 85% 15 min after lornoxicam administration, and remained impaired for 8 h. Platelet aggregation assays are impaired for at least 8 h after lornoxicam application. Therefore perioperative analgesia by use of lornoxicam should be carefully administered under consideration of subsequent platelet dysfunction.
Critical Care Medicine, 1994
Anesthesia & Analgesia, 2000
Endotracheal intubation has been performed during the administration of propofol anesthesia witho... more Endotracheal intubation has been performed during the administration of propofol anesthesia without neuromuscular blockade. In this study, we determined the propofol dose required for conventional nasotracheal or for fiberoptic nasotracheal intubation of all patients. Thirty-two patients undergoing maxillofacial surgery were randomly assigned to the conventional (n = 16) or to the fiberoptic (n = 16) intubation group. In both groups, anesthesia was induced by using IV fentanyl and IV titrated propofol according to clinical need (spontaneous respiration rate, verbal response). An endotracheal tube was placed nasally in the pharynx and the vocal cords visualized by using a fiberscope inserted via the tube. In the conventional group, the larynx was visualized additionally with a laryngoscope blade (Miller). In both groups propofol was titrated until the vocal cords opened. Patients were tracheally intubated, and the propofol dose was recorded. In all patients, the trachea could be intubated without the use of muscle relaxants. Considerable interindividual differences of dose requirements were observed. The amount of propofol required in the conventional group was significantly (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.0001) larger (median +/- SD: 2.74 +/- 1.59 mg/kg; range 1.95-7.07 mg/kg) than in the fiberoptic group (1.37 +/- 0.59 mg/kg; 0.72-2.86 mg/kg). Hemodynamics remained stable in all patients. Postintubational hoarseness occurred in three patients of each group. Fiberoptic nasal intubation without a muscle relaxant can be facilitated with significantly smaller and more predictable dosages of propofol than conventional nasal endotracheal intubation. The possibility of titrating the propofol dose under assisted ventilation until the vocal cords open during fiberoptic nasotracheal intubation and the better predictability of the required dose favors the fiberoptic approach. In this study, contrary to all preceding studies using predefined doses of propofol and opioids, we determined the minimal required propofol dose in combination with fentanyl for conventional or fiberoptic nasotracheal intubation without muscle relaxants.
Anesthesia & Analgesia, 2008
Ultrasonographic observation of peripheral nerve blocks enables direct visualization of the sprea... more Ultrasonographic observation of peripheral nerve blocks enables direct visualization of the spread of local anesthetic around the targeted nerves. Similarly, ultrasonography may be used to determine the site of local anesthetic placement when landmark-based techniques are used. We performed a study to determine the actual location of local anesthetic when ilioinguinal/iliohypogastric nerve blocks are performed using landmark-based techniques in children in an attempt to explain a failed block. After induction of general anesthesia (1 minimum alveolar anesthetic concentration halothane and laryngeal mask airway), 62 children scheduled for inguinal surgery received an ilioinguinal/iliohypogastric nerve block based on standard anatomical landmarks. Ultrasonography was then used to determine the actual location of local anesthetic placement. The anesthesiologist performing the block was blinded to the ultrasonographic investigation. Successful blocks were recorded either when the local anesthetic surrounded the nerves or were based on clinical signs after skin incision. In 14% of the blocks, the local anesthetic was administered correctly around the nerves resulting in successful blocks. In the remaining 86%, the local anesthetic was administered in adjacent anatomical structures (iliac muscle 18%, transverse abdominal muscle 26%, internal oblique abdominal muscle 29%, external oblique abdominal muscle 9%, subcutaneous 2%, and peritoneum 2%), and 45% of these blocks failed. Accurate placement of local anesthetic around the ilioinguinal/iliohypogastric nerves in children is seldom possible when landmark-based techniques are used. In the majority of patients, the local anesthetic was inaccurately placed in adjacent anatomical structures with unpredictable block results.
Burns, 1999
In severely burned patients the approach to the central vein is often dicult due to concomitant e... more In severely burned patients the approach to the central vein is often dicult due to concomitant edema, but also due to the fact that the skin area, where commonly used approaches are performed, is burned as well, whereas the axillary region is often not involved. In order to perform an axillary approach to the central vein as an alternative to the commonly used approaches in patients, an anatomical dissection in fresh human cadavers was carried out. Considering the anatomical landmarks which were found during dissection of the axillary region, the axillary approach to the central vein was used in 35 patients in our intensive burn care unit with unaected axillary skin. In three cases the only complication observed was an occasional puncture of the axillary artery without major hematoma. The infection rate of the catheters was similar to the commonly used puncture sites. This approach to the central venous line in severely burned patients can be recommended.
Anesthesiology, 1998
Wolters Kluwer Health may email you for journal alerts and information, but is committed to maint... more Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your privacy and will not share your personal information without your express consent. For more information, please refer to our Privacy Policy. ... An abstract is unavailable. This article is ...
Acta anaesthesiologica Scandinavica. Supplementum
... Physiologyc basis of a bedside screening test. JAMA 1966: 196: 754-756. 15. Tapson VF,Witty L... more ... Physiologyc basis of a bedside screening test. JAMA 1966: 196: 754-756. 15. Tapson VF,Witty LA. Massive pulmonary embolism. Diag-nostic and therapeutic strategies. Clin Chest Med 1995: 16 16. Sdunid C, Zietlow S, Wagner TO, Laas J, Borst HG. ...
Infusionstherapie und Transfusionsmedizin
ABSTRACT
Background. Recent studies have shown that ultrasound guidance for paediatric regional anaesthesi... more Background. Recent studies have shown that ultrasound guidance for paediatric regional anaesthesia can improve the quality of upper extremity and neuraxial blocks. We therefore investigated whether ultrasound guidance for sciatic and femoral nerve blocks prolongs sensory blockade in comparison with nerve stimulator guidance in children.