[Does total intravenous anesthesia have an effect on the course of the postoperative phase?].
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Anesthesia Recovery Period↗
Biomedical subjects
F W Ahnefeld
Publications and source records attributed to F W Ahnefeld.
Relationship between arterial and peripheral venous catecholamine plasma catecholamine concentrations during infusion of noradrenaline and adrenaline in healthy volunteers.
Noradrenaline and adrenaline were infused IV at 5 different rates (0.01-0.2 micrograms.kg.min-1) for 30 min to volunteers. The plasma catecholamine concentrations were determined by HPLC and electro-chemical detection. At the highest infusion rate, the arterial and venous plasma concentrations of noradrenaline increased from 1.18 to 44.1 nmol.l-1 and from 1.14 to 31.9 nmol.l-1, respectively, and of adrenaline from 0.29 to 23.9 nmol.l-1 and from 0.28 to 19.3 nmol.l-1, respectively. The peripheral venous plasma concentration of noradrenaline averaged 76% of the arterial concentration, and of adrenaline it was 73%. There was a linear relationship between the peripheral venous and arterial plasma noradrenaline and adrenaline concentrations at therapeutic doses.
Adult↗
Stress hormone response during and after cardiopulmonary resuscitation.
The purpose of this study was to assess whether plasma adrenocorticotropin, cortisol, vasopressin, and renin concentrations are higher in resuscitated than in nonresuscitated patients during cardiopulmonary resuscitation, and whether there are possible correlations between these hormones and blood pressure or heart rate in the immediate postresuscitation phase. Of 34 consecutive patients (36-85 yr of age) with out-of-hospital cardiac arrest, 20 could be successfully resuscitated and admitted to hospital, whereas in the remaining 14 patients restoration of spontaneous circulation could not be achieved. During cardiopulmonary resuscitation, median adrenocorticotropin, cortisol, vasopressin, and renin concentrations in the external jugular vein were 237 pg/ml, 32.6 micrograms/dl, 122 pg/ml, and 46.5 ng/l, respectively, in resuscitated patients, and 45 pg/ml (P = 0.018), 18.4 micrograms/dl (P = 0.481), 88 pg/ml (P = 0.049), and 11 ng/l (P = 0.017), respectively, in nonresuscitated patients. Median adrenocorticotropin, cortisol, vasopressin, and renin concentrations were 101 pg/ml, 34.6 micrograms/dl, 22 pg/ml, and 25 ng/l, respectively, 60 min after successful resuscitation. No significant correlations were found between hormone levels and blood pressure or heart rate, but there was a significant negative correlation between the interval from collapse to the start of cardiopulmonary resuscitation and plasma cortisol concentrations during cardiopulmonary resuscitation (Spearman rank correlation coefficient = -0.967, P less than 0.001), indicating an impaired cortisol release from the adrenal cortex. The lower hormone concentrations of the nonresuscitated patients measured during cardiopulmonary resuscitation might indicate an impairment in neuroendocrine response.
Adrenocorticotropic Hormone↗
Effects of diltiazem on oxygen delivery and consumption after asphyxial cardiac arrest and resuscitation.
BACKGROUND AND METHODS: Calcium-channel blockers may attenuate vasospasm after transient ischemia and improve organ blood flow after resuscitation. Our aim was to assess the effect of diltiazem on systemic oxygen delivery and consumption, hemodynamics, electroencephalogram (EEG), and organ blood flow after restoration of spontaneous circulation. After a 3-min period of asphyxial cardiac arrest, 14 pigs (20 to 27 kg) were randomly allocated to treatment with either diltiazem (0.1 mg/kg bolus followed by an iv infusion of 0.025 mg/min/kg over 120 mins) or placebo, given at 5 mins after successful resuscitation. Organ blood flow was measured using tracer microspheres 120 mins after resumption of spontaneous circulation. RESULTS: Median systemic oxygen delivery index values at 30, 60, and 120 mins after restoration of spontaneous circulation were 18.2 mL/min/kg (range 14.8 to 20.7), 16.8 mL/min/kg (13.2 to 20.8), and 19.6 mL/min/kg (16.9 to 21.0), respectively, in the diltiazem group and 13.1 mL/min/kg (11.2 to 14.6), 11.9 mL/min/kg (10.3 to 13.3), and 14.7 mL/min/kg (11.4 to 17.2), respectively, in the control group (p less than .05 for all three comparisons). At the same points in time, median systemic oxygen consumption indices were 3.2 mL/min/kg (range 2.2 to 3.7), 2.1 mL/min/kg (1.9 to 3.0), and 2.6 mL/min/kg (1.8 to 3.8) in the diltiazem group and 2.8 mL/min/kg (2.1 to 4.0), 2.7 mL/min/kg (1.7 to 4.3), and 2.3 mL/min/kg (1.6 to 3.8) in the placebo group (NS). Diltiazem enhanced the postarrest recovery of EEG total power. Right and left cerebral blood flow 120 mins after restoration of spontaneous circulation was significantly (p less than .01) higher in the diltiazem group in comparison with the control group. CONCLUSIONS: Diltiazem causes an increase in systemic oxygen delivery index by promoting vasodilation, but it does not change systemic oxygen consumption index in comparison to placebo treatment. It may be that an impairment in local autoregulation and/or in oxidative metabolism at the cellular or subcellular level was the reason why diltiazem did not improve these derangements. The observed increase in cerebral blood flow and in EEG recovery may be beneficial to the brain after a period of asphyxia.
Acid-Base Equilibrium↗
Relationship between infusion rates, plasma concentrations, and cardiovascular and metabolic effects during the infusion of norepinephrine in healthy volunteers.
OBJECTIVE: To determine the relationship between iv infusion rate, plasma concentrations, and hemodynamic and metabolic actions of norepinephrine. DESIGN: Norepinephrine was administered by using five iv infusion rates (0.01 to 0.2 micrograms/kg/min) for 30 mins each to eight volunteers, for the purpose of constructing cumulative plasma concentration-response curves. SETTING: Laboratory of the Department of Anesthesiology at a university hospital. MEASUREMENTS AND MAIN RESULTS: Systolic and diastolic BP, heart rate, and the plasma concentrations of norepinephrine, glucose, nonesterified fatty acids, and insulin were measured at the end of each infusion rate. During the highest infusion rate, plasma norepinephrine concentrations increased from 199 +/- 75 to 7475 +/- 1071 pg/mL (1.18 +/- 0.44 to 44.18 +/- 6.33 nmol/L). Typical hemodynamic responses, such as increases in BP and decreases in heart rate, were seen, while the plasma concentrations of glucose and nonesterified fatty acids increased from 92 +/- 10 to 132 +/- 17 mg/dL (5.1 +/- 0.6 to 7.3 +/- 0.9 mmol/L) and 11 +/- 4 to 34 +/- 6 mg/dL (0.11 +/- 0.04 to 0.34 +/- 0.06 g/L), respectively, during the 0.2 micrograms/kg/min infusion rate (p less than .05). Despite the increase in glucose concentration, insulin remained at baseline values. Metabolic and hemodynamic effects occurred at similar plasma concentrations throughout the study. CONCLUSIONS: Administration of norepinephrine showed no selective hemodynamic actions. The metabolic responses observed in this investigation were similar to those responses seen during increased endogenous sympathetic nervous system activity, such as stress, exercise, or trauma.
Adult↗
Efficiency of suction pumps for the emergency medicine setting.
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Emergency Medicine↗
Measurement of mucociliary transport velocity in ventilated patients. Short-term effect of general anesthesia on mucociliary transport.
OBJECTIVES: The objectives of this study were to evaluate a method for measuring BTV in ventilated patients and to study the short-term effect of general anesthesia with midazolam, Fentanyl, pancuronium and O2:N2O on BTV. DESIGN: The study included phantom measurements on a bronchoscopy model and the determination of BTV in patients in a convenience sample trial. SETTING: The study took place in a university hospital. PATIENTS: Fourteen patients undergoing major abdominal surgery with planned postoperative mechanical ventilation were included in the study. All patients gave their written informed consent to participate in the study. INTERVENTIONS: Bronchial mucus transport velocity was measured with a small volume (0.05 to 0.08 ml) of technetium 99m-labeled albumin microspheres with an activity of 3 MBq. The radiolabeled bolus was deposited on the dorsal mucosal surface at the distal end of the right and left main bronchus via flexible bronchoscopy. The movement of the microspheres toward the trachea was visualized and recorded using a scintillation camera; quantitative evaluation utilized the condensed image. MAIN MEASUREMENTS AND RESULTS: The technique was validated in a bronchoscopy model and in an intubated patient by moving a radioactive drop in a catheter through the main bronchi at velocities from 0 to 20 mm/min. The velocities determined by the image processing technique correlated well with the data by the model and patient determination (right bronchus, r = 1.0; left bronchus, r = 1.0). In seven ventilated patients, mechanical irritation by the fiberscope produced no significant effect on BTV. The BTV was measured preoperatively in seven conscious patients one day before surgery while they received local anesthesia with 10 ml of 1 percent lidocaine and postoperatively while they received intubation anesthesia. The preoperative and postoperative BTV values showed no significant differences (10.5; 5.7 to 13.7 mm/min; vs 9.7 (3.7 to 15.3) (median with range). CONCLUSION: By this method, bronchial transport velocity can be determined in a relatively short time in ventilated patients. General anesthesia with midazolam, Fentanyl, pancuronium and O2:N2O does not influence BTV.
Adult↗
Adrenaline: relationship between infusion rate, plasma concentration, metabolic and haemodynamic effects in volunteers.
The present study investigated the relationship between supraphysiological plasma concentrations of adrenaline and the resulting haemodynamic and metabolic effects. Adrenaline was administered at five infusion rates (0.01-0.2 micrograms kg-1 min-1) in an escalating sequence to eight volunteers. The arterial plasma concentration of adrenaline increased from 53 +/- 44 to 4349 +/- 818 ng litre-1 during the highest infusion rate. Typical haemodynamic responses, such as increase in blood pressure and heart rate, were seen. The plasma concentrations of glucose and lactate increased from 5.2 +/- 0.4 to 13.7 +/- 1.3 mmol litre-1 and from 0.9 +/- 0.3 to 4.7 +/- 2.6 mmol litre-1, respectively, during the highest infusion rate without a significant increase in insulin concentration. Non-esterified fatty acids increased from 379 +/- 97 to 1114 +/- 331 mumol litre-1 during the 0.06 microgram kg-1 min-1 infusion rate. Adrenaline had no selective haemodynamic effect. If similar metabolic effects occur in patients during treatment with adrenaline or other sympathomimetics, they may further increase breakdown of energy stores in a situation of increased catabolism, and impair utilization of parenteral nutrition.
Adult↗
[New aspects of mechanical cardiopulmonary resuscitation].
New results in the area of mechanical cardiopulmonary resuscitation indicate that during external cardiac massage, the blood flow is achieved both by direct cardiac compression and a generalized increase in the intrathoracic pressure. While, in accordance with the classical theory, the heart is compressed between the sternum and the vertebral column, the thoracic pump mechanism requires a consideration of all blood-carrying structures within the thorax as elastic tubes or chambers that are capable of being compressed by externally administered pressure. Only such variations of the technique presently used may be of benefit which can be achieved with simple adjuncts and which have a positive effect on both mechanisms of blood flow.
Animals↗
[Current guidelines for cardiopulmonary resuscitation].
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Blood Pressure↗
[A noncardiac pulmonary edema following aortocoronary bypass surgery. Diagnosis and therapy based on a case report].
Noncardiac pulmonary edema can occur not only after cardiac surgery with cardiopulmonary bypass but also after noncardiac operations. This so-called transfusion-related acute lung injury (TRALI) has been attributed to the transfusion of homologous blood and plasma. In the presence of normal left ventricular function an acute increase in pulmonary capillary permeability leads to massive protein-rich pulmonary edema, reduced pulmonary function, and intravascular hypovolemia. This may be caused by leukocyte antibodies. Signs and diagnostic and therapeutic procedures are discussed with reference to a case report.
Coronary Artery Bypass↗
Epinephrine versus norepinephrine in prehospital ventricular fibrillation.
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Aged↗
Comparison of different doses of epinephrine on myocardial perfusion and resuscitation success during cardiopulmonary resuscitation in a pig model.
Published results of dose-response effects of adrenergic drugs (epinephrine [E]) vary so much between studies because of differences in animal models and duration of ischemia before drug administration. In this investigation the effects of different doses of E on coronary perfusion pressure (CPP), left ventricular myocardial blood flow (MBF) and resuscitation success were compared during closed-chest cardiopulmonary resuscitation (CPR) after a 4-minute period of ventricular fibrillation in 28 pigs. MBF was measured during normal sinus rhythm using tracer microspheres. After 4 minutes of ventricular fibrillation CPR was performed with the use of a pneumatic piston compressor. After 4 minutes of mechanical measures only, the animals were randomly allocated into four groups of seven, receiving 0.015, 0.030, 0.045, and 0.090 mg/kg E intravenously respectively. MBF measurements were started 45 seconds after E administration; hemodynamic measurements after 90 seconds. Four minutes after the first administration, the same E dose was given before defibrillation. The CPP of animals given 0.015, 0.030, 0.045 and 0.090 mg/kg E were as follows: 16.3 +/- 6.1, 25.6 +/- 5.8, 33.2 +/- 8.4 and 30.4 +/- 6.3 mm Hg. The left ventricular MBF values were: 14 +/- 9, 27 +/- 11, 43 +/- 6, 46 +/- 10 mL/min/100 g. The differences between the groups receiving 0.015 and 0.045 mg/kg and between the groups receiving 0.015 mg/kg and 0.090 mg/kg were statistically significant (P less than .05). Resuscitation success was 14.3%, 42.9%, 100% and 86.7% respectively. A significant difference in resuscitation success was found only between 0.015 mg/kg and 0.045 mg/kg E.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Physical characteristics of devices for artificial respiration].
Expired air resuscitation forms an essential part of First Aid in patients with respiratory insufficiency. The use of devices should encourage the rescuer to start the measure, make it easier to perform and protect him from a possible transmission of infectious material. 17 devices (mask, tube instruments) were examined in respect of their physical properties (resistance, leakage). None of them fulfilled all the criteria relevant for their use. In most of them changes and modifications seem to be necessary. Mask and tube instruments have definitive disadvantages compared to foil-like adjuncts which are being developed at present.
Humans↗
[Pneumonia prevention in long-term mechanically ventilated patients: selective skin decontamination according to Stoutenbeek or prevention of colonization according to Unertl? A prospective randomized comparison of both treatments].
In a prospective randomised study, the effects of two different colonisation prophylaxis techniques on colonisation and pulmonary infection were investigated in 40 critically ill patients with long-term ventilatory support (greater than or equal to 4 days). 20 patients were selectively decontaminated with 4 x 100 g polymyxin E, 4 x 80 mg tobramycin and 4 x 500 mg amphotericin B, administered through the gastric tube and with an antimicrobial sticky paste in the oropharynx (group I). 20 patients received 50 mg of polymyxin B and 80 mg of gentamicin dissolved in 10 ml of 0.9% saline at 6 h intervals into nose, oropharynx and stomach as well as 300 mg of amphotericin B in the oropharynx only (group II). All patients received cefotaxime systemically in the first 3 days. In group I gram-negative aerobic bacteria in the pharynx decreased from 35% to 0%, in group II from 40% to 10% and in the rectum from 80% to 61% (10% in the second week) in Group I and from 100% to 73% (33% in the second week) in group II. The decrease in gram-negative microorganisms was accompanied by an increase in the frequency of Staphylococcus epidermidis. In group I, two patients developed pneumonia and two patients urinary tract infections, in group II two patients suffered from pneumonia and 3 patients urinary tract infections. Both regimes are effective methods of prophylaxis for lowering colonisation with gram-negative aerobic bacteria and the frequency of pneumonia in patients requiring long-term mechanical ventilation. A possible selection of gram-positive bacteria must be appropriately monitored.
Adult↗
Influence of epinephrine on systemic, myocardial, and cerebral acid-base status during cardiopulmonary resuscitation.
During cardiopulmonary resuscitation (CPR), arterial pH and carbon dioxide tension (PCO2) do not reflect the marked acidosis and hypercapnia seen in venous blood samples during CPR. Epinephrine causes an increase in myocardial and cerebral blood flow during CPR, but the influence on regional venous PCO2 and pH is as yet unknown. Fourteen pigs were allocated to receive either 0.9% saline (n = 7), or 45 micrograms/kg epinephrine (n = 7) after 5 min of ventricular fibrillation and 3 min of open-chest CPR. Blood samples were obtained during CPR from the aorta, pulmonary artery, great cardiac vein, and sagittal sinus before and 90 s and 5 min after drug administration. Regional blood flow was measured with tracer microspheres. Plasma catecholamines were quantified by high-performance liquid chromatography in arterial blood. PCO2 90 s after drug administration in arterial, mixed venous, myocardial venous, and cerebral venous blood were (means +/- SD) 36 +/- 8, 67 +/- 9, 74 +/- 14, and 79 +/- 19 mmHg in the control group and 35 +/- 11, 62 +/- 12, 73 +/- 10, and 71 +/- 14 mmHg in the epinephrine group. pH values 90 s after drug administration in the same blood samples were 7.29 +/- 0.11, 7.11 +/- 0.09, 7.04 +/- 0.09, and 7.07 +/- 0.10 in the control group and 7.31 +/- 0.13, 7.17 +/- 0.07, 7.08 +/- 0.08, and 7.07 +/- 0.12 in the epinephrine group. Despite a significant increase in myocardial and cerebral blood flow after epinephrine, PCO2 and pH in all blood samples were not different from those of the control group. (ABSTRACT TRUNCATED AT 250 WORDS)
Acid-Base Equilibrium↗
Endotracheal and endobronchial lidocaine administration: effects on plasma lidocaine concentration and blood gases.
OBJECTIVE: To compare four different methods of endotracheal lidocaine administration with respect to the site of administration. DESIGN: Randomized controlled trial. SETTING: University hospital. PATIENTS: Thirty-two female patients (43.6 +/- 11.5 years old) undergoing elective gynecologic operations with an anesthesiologic risk classification not higher than ASA II. All patients gave their written informed consent to participate in the study. INTERVENTIONS: Lidocaine at a dose of 2 mg/kg, diluted with normal saline to a total volume of 10 mL, was administered to eight patients by instilling the drug solution from a 10-mL syringe directly into the outer aperture of the endotracheal tube. All other study patients received lidocaine under bronchoscopic control through the work channel of the bronchoscope either a) deep endotracheally, b) into the right main bronchus, or c) into the right lower lobe bronchus. At 10 points in time after drug administration, blood samples were taken for measurement of lidocaine plasma concentration (using high-pressure liquid chromatography) and blood gas analysis. MAIN MEASUREMENTS AND RESULTS: Therapeutic blood concentrations (greater than or equal to 1.4 micrograms/mL) could be achieved and toxic blood concentrations (greater than or equal to 6 micrograms/mL) could be avoided with all methods of administration. No significant difference was found between the different methods with regard to peak concentration, time to peak, onset and duration of therapeutic levels, or relative bioavailability. A significant (p less than .05) decrease in PaO2 to 75% of the baseline was seen with all methods used. CONCLUSIONS: Because no route of lidocaine administration was superior to the others, the simplest method (instillation into the endotracheal tube) should be used.
Adult↗
Comparison of standard and high-dose adrenaline in the resuscitation of asystole and electromechanical dissociation.
Sixty-eight adults with cardiac arrest (asystole and electromechanical dissociation) were randomly allocated for treatment with standard (1 mg) or high-dose epinephrine (5 mg). If the first dose of adrenaline (1 or 5 mg) failed, standardized advanced life-support was applied in all cases. High-dose adrenaline was associated with higher initial resuscitation success rates (16 of 28) than standard-dose adrenaline (6 of 40), whereas hospital discharge rates were not significantly different between the groups. Blood pressure was significantly higher in the high-dose adrenaline group in comparison to the standard dose at 1 and 5 min after resuscitation. Although high-dose adrenaline appears to improve cardiac resuscitation success, the duration of global cerebral ischaemia seems to determine the ultimate outcome.
Aged↗