Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Nov 1990
Pressure pain thresholds in volunteers and herniorrhaphy patients.
Pressure algometry is a method to estimate pressure pain sensitivity in tissues. The aim of the present study was to evaluate the reproducibility of pressure pain thresholds (PPT) in the abdominal integument and to evaluate the use of pressure algometry as a measure of wound tenderness following surgery. PPT was determined in 20 healthy volunteers on two separate examinations, and in 14 patients at the incisional site before and following inguinal herniotomy. ⋯ In surgical patients a significant decrease in PPT was observed following operation. Morphine 0.07 mg/kg caused a slight but significant increase in PPT. Pressure algometry may be useful to study nociceptive mechanisms and the dynamics of wound pain in surgical patients.
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Acta Anaesthesiol Scand · Nov 1990
Negative effect of insufflation on cardiac output and pulmonary blood volume.
In 14 anaesthetized young pigs the changes in pulmonary blood flow and pulmonary blood volume (Qp) during mechanical ventilation were quantified. Ventilation was performed at 10 cycles per min and tidal volume (VT) was adjusted to an arterial PCO2 of about 40 mmHg (5.3 kPa). In 4 animals, 7 ventilatory cycles with an inspiratory pause (IP) of 7.2 s but different tidal volumes were inserted at intervals of 5 min to determine the decrease in Qp (delta Qp) from the differences between right ventricular (Qs,rv) and left ventricular (Qs,lv) stroke volume, and to relate delta Qp to VT. ⋯ Stroke volumes were derived from the EM-flow curves. In the other 10 experiments, Qs,lv was derived from the aortic pulse contour. Beat-to-beat analyses of Qs,rv and Qs,lv and blood pressures during the normal ventilatory cycles and those with an IP revealed the following: 1) The end-expiratory RV output and LV output were constant and were defined as baseline values. 2) The accumulated decrease in Qs,rv during insufflation caused a mean deficit in cardiac output of 10.3 +/- 3.2% (s.d.), n = 135; the same was found for Qs,lv, indicating the pulse contour as a useful method to estimate the variations in cardiac output during a ventilatory cycle.(ABSTRACT TRUNCATED AT 250 WORDS)
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Acta Anaesthesiol Scand · Nov 1990
The use of a laryngeal mask airway in spontaneously breathing patients.
The Laryngeal Mask Airway (LMA) is a new type of oropharyngeal airway that provides an alternative to endotracheal intubation and standard mask anaesthesia in certain cases. Once the patient is adequately anaesthetised, it can be inserted blindly, without recourse to laryngoscopy or muscle relaxants. ⋯ Postoperative problems were minimal and 97.6% of our patients said that they would prefer a similar anaesthetic in future. LMA does not guarantee against the risk of aspiration and it is not recommended for use in patients who may have a full stomach.
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Acta Anaesthesiol Scand · Oct 1990
Randomized Controlled Trial Comparative Study Clinical TrialThe effect of nitrous oxide on EEG spectral power during halothane and isoflurane anaesthesia.
The effect of N2O on EEG during halothane and isoflurane anaesthesia was studied in 24 elective-surgery patients. The total EEG power and various power bands were analysed with fast Fourier transform power spectra. Anaesthesia was induced by mask. ⋯ Alpha- and beta-range EEG power and total power decreased during N2O in both groups. Delta- and theta-range power increased during N2O in the halothane group. The study shows that the effect of nitrous oxide should be taken into consideration when EEG is being studied or monitored during anaesthesia.
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Acta Anaesthesiol Scand · Oct 1990
Randomized Controlled Trial Clinical TrialHeat and moisture exchangers and the body temperature: a peroperative study.
The importance of conditioning the inhaled gas for maintaining the body temperature during artificial respiration was investigated. The mean body temperature (MBT) was deduced from readings from five measuring sites, four of which were situated at the skin and the fifth in the rectum. Temperature recordings were made every 15th min. ⋯ Our finding correlated fairly well with a predicted reduction of heat loss of 26.0 kJ/h for the type of HME used. A certain margin of error seemed to be inevitable in measuring body temperatures, and the reason for this is discussed. Our results support the fact that the investigation is adequately designed, and that the heat conserved with an HME is rather low.