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P G Berthelsen

Publications and source records attributed to P G Berthelsen.

At least 19 recordsLinked to original sources
PubMed2006

Double jeopardy.

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Catheterization, Central Venous↗
PubMed2006

Cardiac output--pulse contour analysis vs. pulmonary artery thermodilution.

BACKGROUND: The aims of this study were to determine the agreement between pulmonary artery thermodilution (PA-TD), transpulmonary thermodilution (TP-TD) and the pulse contour method, and to test the ability of the pulse contour method to track changes in cardiac output. METHODS: Cardiac output was determined twice before cardiac surgery with both PA-TD and TP-TD. The precision (two standard deviations of the difference between repeated measurements) and agreement of the two methods were calculated. Post-operatively, cardiac output was determined with the PA-TD and pulse contour methods, and the bias and limits of agreement were again calculated. Finally, in patients with heart rates below 60 beats/min or a cardiac index of less than 2.5 l/min/m2, atrial pacing was started and the haemodynamic consequences were monitored with the PA-TD and pulse contour methods. RESULTS: Twenty-five patients were included. The precisions of PA-TD and TP-TD were 0.41 l/min [95% confidence interval (CI), +/- 0.07] and 0.48 l/min (95% CI, +/- 0.08), respectively. The bias and limits of agreement between PA-TD and TP-TD were - 0.46 l/min (95% CI, +/- 0.11) and +/- 1.10 l/min (95% CI, +/- 0.19), respectively. Post-operatively, the bias and limits of agreement between the PA-TD and pulse contour methods were 0.07 l/min and +/- 2.20 l/min, respectively. The changes in cardiac output with atrial pacing were in the same direction and of the same magnitude in 15 of the 16 patients. CONCLUSION: The precision of cardiac output measurements with PA-TD and TP-TD was very similar. The transpulmonary method, however, overestimated the cardiac output by 0.46 l/min. Post-operatively, cardiac output measurements with the PA-TD and pulse contour methods did not agree, but the pulse contour method reliably tracked pacing-induced changes in cardiac output.

Adult↗
PubMed2005

Precision of bolus thermodilution cardiac output measurements in patients with atrial fibrillation.

BACKGROUND: The precision of bolus thermodilution cardiac output measurements in patients with atrial fibrillation (AF) has not previously been determined. A priori we suspected that the precision would be lower in patients with AF than in patients with sinus rhythm (SR). Consequently, we also determined if the precision could be improved by injecting the thermal indicator into the right ventricle instead of the right atrium. METHODS: Cardiac output was determined as the average result of four injections of 10 ml of iced saline. Replicate measurements were performed with thermal indicator injections into the right atrium and ventricle. The coefficients of variation and the precisions were calculated. RESULTS: In the 25 patients with AF, mean cardiac output was 3.96 l min(-1) (range 2.4-7.4), the coefficient of variation 0.073 (95% CI +/- 0.011), and the precision 0.38 l min(-1) (95% CI +/- 0.14) with injection into the right atrium. In the 25 patients with SR, mean cardiac output was 4.73 l min(-1) (range 2.4-7.3), the coefficient of variation 0.047(95% CI +/- 0.006), and the precision 0.38 l min(-1) (95% CI +/- 0.14). In both groups, an agreement analysis demonstrated that the injection of indicator into the right ventricle resulted in a significantly higher cardiac output [AF+0.25 (95% CI +/- 0.15) l min(-1), SR+0.29 ( +/- 0.20) l min(-1)]. CONCLUSION: The coefficient of variation for cardiac output determinations is 55% higher in patients with AF. Two measurements, separated by time or intervention, must differ by 15% in AF patients and 9% in SR patients before one can be 95% confident that a real change has taken place.

Aged↗
PubMed2004

Thermodilution cardiac output--are three injections enough?

BACKGROUND: Bolus thermodilution cardiac output measurements have been a mainstay in clinical monitoring of critically ill patients for more than 30 years. Usually the results of an arbitrarily chosen number (1-6) of thermal indicator injections are averaged to increase the reliability of the measurement. The number of injections needed to achieve a given level of precision has, however, not previously been systematically investigated. METHODS AND RESULTS: In 80 hemodynamically stable patients cardiac output was determined as the average of eight injections of 10 ml of iced saline. From the 638 measurements we examined the relationship between the number of thermal indicator injections and the precision of the resulting cardiac output estimate. Furthermore, the association between the number of injections and the least detectable difference among two sets of measurements was established. CONCLUSION: The current study shows that one needs to average the results of four injections to be 95% confident that the result is within 5% of the 'true' cardiac output and that two series of four measurements have to differ by at least 7% before one can be sure (95%) that a change in cardiac function has taken place.

Adult↗
PubMed2003

The first intensive care unit in the world: Copenhagen 1953.

After an extensive survey of the medical literature we present compelling evidence that the first intensive care unit was established at Kommunehospitalet in Copenhagen in December 1953. The pioneer was the Danish anaesthetist Bjørn Ibsen. The many factors that interacted favourably in Copenhagen to promote the idea of intensive care therapy, half a century ago, are also described.

Anesthesiology↗
PubMed2002

Thermodilution cardiac output. Cold vs room temperature injectate and the importance of measuring the injectate temperature in the right atrium.

BACKGROUND: The feasibility of thermodilution cardiac output measurements with the more convenient room temperature thermal indicator instead of cold injectates has been repeatedly investigated. However, the issue has not been addressed with the appropriate statistical approach advocated by Altman and Bland. Furthermore, we wished to determine if the incorporation of a second thermistor in the thermodilution catheter, to measure the temperature of the thermal indicator where it is delivered into the right atrium/superior caval vein, would result in more precise cardiac output measurements. METHODS: Fifty patients were randomized to receive a single or dual thermistor pulmonary artery thermodilution catheter. Cardiac output was calculated as the average of four injections of 10 ml of isotonic saline. Precision (2 x SD of differences in replicate measurements) for the two catheters and injectate temperatures, and bias and limits of agreement between measurements, with cold and room temperature injectates, were determined. RESULTS: Precision was (0 degrees C) 0.42 l/min and (20 degrees C) 0.90 l/min, and bias and limits of agreement -0.83 l/min and -1.93-0.27 l/min for the single thermistor catheter. For the dual thermistor system precision was (0 degrees C) 0.34 l/min and (20 degrees C) 0.58 l/min. Bias and limits of agreement were -0.03 l/min and -0.61-0.55 l/min. CONCLUSION: The second thermistor is redundant if cold injectates are used. If one wishes to use room temperature injectates the single thermistor system is inadequate. A dual thermistor catheter is, on the other hand, acceptable.

Adult↗
PubMed2001

Lack of agreement between thermodilution and carbon dioxide-rebreathing cardiac output.

BACKGROUND: A continuous, accurate, non-invasive monitor of cardiac output would represent a major step forward in patient management. A cardiac output computer, NICO2, based on the Fick principle and an automatic partial carbon dioxide (CO2)-rebreathing technique has just become available. We compared the performance of this monitor with the standard thermodilution method. METHODS: Thirty patients were investigated after cardiac surgery. Replicate measurements were performed simultaneously with the thermodilution and NICO2 techniques. An Altman-Bland analysis was used to assess repeatability of each of the two methods and to determine the agreement between the two techniques. RESULTS: The repeatabilities of thermodilution and CO2-rebreathing cardiac output were excellent, with coefficients of repeatability of 0.35 l/min and 0.60 l/min. Mean thermodilution and NICO2 cardiac output were 4.4 l/min (SD 0.9, range 2.7-6.1) and 4.6 l/min (SD 1.3, range 1.6-6.9). A comparison of the methods, however, revealed excessive limits of agreement (+/-1.80 l/min). CONCLUSION: The agreement between the NICO2 derived cardiac output and the de facto standard - thermodilution cardiac output - is poor. The methods are not interchangeable with the present version of the NICO2. The repeatability of the partial CO2-rebreathing technique holds promise that a sufficient accuracy may be obtained by suitable modifications of the monitor's algorithms.

Adult↗
PubMed2001

Impact of off-pump coronary artery surgery on myocardial performance and beta-adrenoceptor function.

OBJECTIVE: To determine the hemodynamic changes during beating heart revascularization of the left anterior descending artery, the circumflex artery, and the right coronary artery as well as cardiovascular beta-adrenoceptor function before and after off-pump coronary artery bypass surgery. DESIGN: Prospective study. SETTING: University department of cardiothoracic anesthesia. PARTICIPANTS: Twenty patients scheduled for off-pump coronary artery bypass surgery using the Octopus 2 stabilizer system. INTERVENTIONS: Isoproterenol, 4 microg, was administered intravenously after induction of anesthesia and again after surgery to monitor cardiac beta-receptor function. MEASUREMENTS AND MAIN RESULTS: The hemodynamic responses to isoproterenol and cardiovascular variables were monitored before, during, and after immobilization of the target coronary artery with catheters in the radial and pulmonary arteries. During surgery on the left anterior descending artery (n = 23), stroke volume and cardiac index decreased 17 mL (21%) and 400 mL (17%). During revascularization of the circumflex artery (n = 9), stroke volume and cardiac index decreased 19 mL (28%) and 300 mL (17%). During surgery on the posterior aspect of the heart (n = 13), stroke volume and cardiac index decreased 22 mL (29%) and 400 mL (17%). All the cardiovascular variables had returned to baseline values 5 minutes after releasing the heart. The hemodynamic responses to isoproterenol were equal before and after surgery. CONCLUSION: This study provides evidence that the hemodynamic changes associated with off-pump surgery on the 3 major coronary arteries are similar and of short duration. No desensitization of cardiovascular beta-adrenoceptors was found. This finding is in contrast to the deterioration in beta-adrenoceptor function seen after surgery with cardiopulmonary bypass.

Adrenergic beta-Agonists↗
PubMed2000

Hearing loss after cardiopulmonary bypass surgery.

Hearing loss (HL) is a rare complication following cardiac surgery with extracorporal circulation (CSWEC) or other non-otologic surgery under general anesthesia, as is HL caused by loss of cerebrospinal fluid during neurosurgery or spinal anesthesia. The incidence of HL after CSWEC is not known since preoperative hearing testing is not commonly done and a perioperative HL may occur unnoticed. We present four cases of profound sensorineural hearing loss following CSWEC for coronary artery bypass or cardiac valve surgery. The hearing loss was noticed immediately on waking from anesthesia in three of the patients, whereas the fourth patient noticed decreased hearing during the first postoperative week. In all patients audiological investigation suggested a cochlear etiology of the HL. The possible mechanisms for HL are discussed. HL after CSWEC is most likely caused by a microembolism generated by atheromatous material.

Adult↗
PubMed1999

Monitoring of beta-receptor sensitivity in cardiac surgery.

OBJECTIVE: To determine the repeatability of the hemodynamic response to repeated isoproterenol challenge doses to validate the standardized isoproterenol sensitivity test as an index of cardiovascular beta-receptor function. DESIGN: Prospective, single-blind, nonrandomized clinical trial. SETTING: University department of cardiothoracic anesthesia. PARTICIPANTS: Twenty middle-aged men scheduled for primary elective coronary artery bypass surgery, 10 of whom had been treated with cardioselective beta1-antagonists for more than 3 months. INTERVENTIONS: After induction of anesthesia and baseline hemodynamic evaluation, cardiac beta-receptor sensitivity was estimated from the chronotropic/inotropic responses to four intravenous 4-microg isoproterenol bolus doses. MEASUREMENTS AND MAIN RESULTS: Baseline cardiovascular function and pharmacodynamic response to the four isoproterenol challenge doses were monitored with catheters in the radial and pulmonary arteries (thermodilution). Heart rate was continuously recorded and calculated from the electrocardiogram. Baseline hemodynamic status and response to the first 4 microg of isoproterenol were similar in the 10 patients treated with beta1-antagonists and the rest of the patients. In all 20 patients, heart rate response to the three subsequent isoproterenol challenge doses decreased progressively by 28%. CONCLUSION: The standardized isoproterenol sensitivity test is unreliable for clinical monitoring of cardiac beta-adrenoceptor function.

Adrenergic beta-Agonists↗
PubMed1998

[Do cardioselective beta-antagonists block the cardiac beta-receptor function also in the long run?].

As the human cardiomyocyte expresses both beta 1 and beta 2 adrenoceptors it is to be expected that the inhibition of one species of receptors can be counteracted by the other. This hypothesis was tested in 40 middle-aged men scheduled for coronary artery bypass surgery. Half the patients had been treated with cardioselective beta 1 antagonists for more than three months while the 20 control patients had never been beta-blocked. The haemodynamic status after induction of a standardized fentanyl/midazolam anaesthesia and the sensitivity of the cardiovascular beta-adrenoceptors to isoprenaline titration were similar in both groups. In conclusion, patients chronically treated with cardioselective beta 1-blockers compensate for the perturbation to such a degree that their cardiovascular function is indistinguishable from patients who have never received beta-blockers.

Adrenergic beta-Antagonists↗
PubMed1997

Are patients chronically treated with beta 1-adrenoceptor antagonists in fact beta-blocked?

OBJECTIVE: To determine cardiovascular beta-receptor function in patients with ischemic heart disease chronically treated with beta 1-adrenoceptor antagonists. DESIGN: Prospective, single-blind, nonrandomized clinical trial. SETTING: University Department of Cardiothoracic Anesthesia. PARTICIPANTS: Forty middle-age men scheduled for primary elective coronary artery bypass surgery. Twenty patients were treated with beta 1-antagonists. INTERVENTIONS: After induction of anesthesia, increasing intravenous bolus doses of isoproterenol were administered in order to increase heart rate more than 25 BPM. From this dose-response curve, the isoproterenol dose needed to increase heart rate by exactly 25 BPM was calculated. MEASUREMENTS AND MAIN RESULTS: Baseline cardiovascular variables and the pharmacodynamic responses to isoproterenol were monitored with catheters in the radial and the pulmonary artery (thermodilution catheter). Heart rate was continuously calculated from the electrocardiogram. The hemodynamic status after induction of a standardized fentanyl anesthesia and the chronotropic and inotropic responses to the isoproterenol titration procedure were identical in the 20 beta 1-blocked patients and in the 20 control patients. The median dose of isoproterenol needed to increase heart rate 25 BPM was 10.9 micrograms in the beta-blocked patients and 9.4 micrograms in the control group. CONCLUSION: Patients chronically treated with beta 1-antagonists compensate for the perturbation to such a degree that cardiovascular beta-receptor function is in fact normal.

Adrenergic beta-Antagonists↗
PubMed1996

[Large epiglottic lipoma. Intubation method for large tumors in the pharynx and larynx].

Large benign tumours in the aperture of the larynx are uncommon, and they are especially rare on the epiglottis. They are, however, important as they may cause fatal airway obstruction particularly at induction of general anaesthesia. We present a patient with a large lipoma originating in the vallecula epiglottica and the lingual surface of the epiglottis. The difficulties involved in tracheal intubation and possible solutions are discussed. In this case intubation was performed under local anaesthesia with the patient fully awake. A commissure laryngoscope was used for visualisation of the laryngeal inlet and a flexible bougie was inserted into the trachea. After removal of the laryngoscope a 7 mm ID endotracheal tube was advanced over the bougie into the trachea. After securing the airway in this way general anaesthesia was induced and the table tennis ball sized lipoma was uneventfully removed.

Epiglottis↗