Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Aug 1993
Hemodynamic changes associated with thermodilution cardiac output determination in canine acute blood loss or endotoxemia.
Since the technique of thermodilution (TD) cardiac output measurement, per se, causes hemodynamic alterations, the author examined whether the alterations elicited by iced injectate are augmented in the presence of acute blood loss or endotoxemia, compromised conditions frequently associated with critically ill patients. Acute blood loss (N = 8) and endotoxemia (N = 8) were induced by withdrawing arterial blood approximately 20-30 ml.kg-1 over 30 min and by a slow intravenous infusion of E. coli endotoxin 2.5-3.0 mg.kg-1 over 10 min, respectively, in anesthetized dogs. The magnitudes of decreases in mean arterial and pulmonary artery pressures during slowing of heart rate (HR) following injection of iced injectate 3 ml were slightly less in acute blood loss than in normovolemia, whereas in endotoxemia the degree of mean arterial pressure decrease during slowing of HR following iced injectate 3 ml was slightly less as compared with that before endotoxemia. ⋯ No profound hemodynamic changes were observed during any TD cardiac output measurements under both conditions. Cardiac output estimated by TD correlated closely with pulmonary blood flow measured by electromagnetic flowmeter in endotoxemia (r > 0.9) but not during acute blood loss. These results indicate that TD cardiac output determination does not cause serious hemodynamic alterations in endotoxemia or acute blood loss, and can estimate right ventricular output accurately in endotoxemia but not in acute blood loss.
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Acta Anaesthesiol Scand · Aug 1993
Effects of adenosine triphosphate (ATP) on somatosensory evoked potentials in humans anesthetized with isoflurane and nitrous oxide.
In order to examine the usefulness of adenosine triphosphate (ATP) as an adjuvant to anesthesia for surgery requiring intraoperative somatosensory evoked potential (SSEP) monitoring, we have studied the effects of ATP on SSEPs in patients anesthetized with isoflurane and nitrous oxide (N2O). A control recording of SSEP was performed while anesthesia was maintained with 0.5% end-tidal concentration of isoflurane in 60% N2O. The recordings were repeated after an ATP infusion had been added to this basal anesthesia at the rates of 100 micrograms.kg bw-1.min-1 and 200 micrograms.kg bw-1.min-1. ⋯ The amplitude of the cortical component of SSEP was lowered by 1.5% isoflurane, which also increased both cortical and spinal latencies as well as central conduction time (CCT). In contrast ATP infusions at both rates induced no significant changes in latencies, amplitude and CCT. The results indicate that ATP infusion combined with 0.5% isoflurane in 60% N2O can be a useful anesthetic technique for intraoperative SSEP monitoring because adequate anesthetic depth can be maintained by a low concentration of anesthetics without further suppression of SSEPs.
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Acta Anaesthesiol Scand · Aug 1993
Intrathecal anaesthesia in patients under 45 years: incidence of postdural puncture symptoms after spinal anaesthesia with 27G needles.
Postoperative headache and backpain has limited the use of intrathecal anaesthesia in younger patients (15-45 years). We studied postoperative complaints among 133 healthy young patients (mean age 30.0 years, 47% females) who received spinal anaesthesia with a 27G needle. Postoperatively, 5 patients (4%) complained of postdural puncture headache (PDPH), 18 (14%) reported nonspecific headache, while 27 (20%) suffered from backpain. ⋯ One hundred and sixteen patients (87%) would accept spinal anaesthesia if they were to undergo the same surgical procedure again. Compared to other studies, we find the incidence of postanaesthetic complaints to be acceptable, also among day-care patients. The PDPH seemed to be lightly incapacitating, and only one patient required blood patching.
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Acta Anaesthesiol Scand · Aug 1993
Randomized Controlled Trial Clinical TrialAnaesthesia for coronary artery bypass grafting: opioid-analgesia combined with either flunitrazepam, propofol or isoflurane.
This is a prospective, open, randomized study comparing three different anaesthetic regimens with respect to haemodynamic stability (cardiac index and pressure measurements), ischaemia (ECG), and loss of awareness (midlatency auditory evoked potentials in 58 patients undergoing coronary artery surgery. Anaesthesia was based on fentanyl 0.01 mg kg-1 bw for induction and 0.8-2.0 mg h-1 in combination with nitrous oxide for maintenance before cardiopulmonary bypass and 0.2-0.6 mg h-1 without nitrous oxide during and after cardiopulmonary bypass. Eighteen patients were anaesthetised with flunitrazepam 0.01 mg kg-1 bw for induction and received thereafter 1-2 mg h-1 for maintenance (group F). ⋯ Surgery and sternotomy caused an increase in SVI and APs/SV in all groups. Differences between the groups were only found for systemic pressures, which after sternotomy were lowest in group I and before cardiopulmonary bypass were highest in group F. After termination of bypass all groups showed an increase in HR and a decrease in SVI, SVR, and LVSWI compared to the awake state, while CI remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)