Showing papers in "Acta Anaesthesiologica Scandinavica in 1992"
TL;DR: Experimental evidence suggests that results of treatment in injured and operated patients can be improved by controlling immune responses and their mediator systems, and the current level of knowledge of immune responses is already helping to avoid many immune‐mediated complications.
Abstract: Alterations have been found to occur in every component of immune response during anaesthesia and surgery. These alterations represent the body's general physiological responses and are mainly dependent on the extent of surgery, as well as other factors such as the patient's age and health status, medication and blood transfusion. Anaesthetic and operative complications have profound effects on these responses. Basically, the immune response to anaesthesia and surgery is a beneficial reaction, needed in local host defences and wound healing and in preventing the body from making autoantibodies against its own tissues. The responses may, however, contribute to the development of postoperative infections and spread of malignant disease. During uncomplicated conventional surgery, the immune response usually passes clinically unnoticed without any harmful effects. Absent responses and excessively high responses, on the other hand, harm the patient. Our understanding of immunological phenomena and our possibilities of controlling mediator activation are now lagging behind the technical advances made in operative treatment. If we want to decrease operative morbidity and mortality to below their present levels, more attention should be directed to immune responses to major surgery, injuries and operative complications with massive mediator release which place the surgical patient at risk. Experimental evidence suggests that results of treatment in injured and operated patients can in the future be improved by controlling immune responses and their mediator systems. Our current level of knowledge of immune responses is already helping us to avoid many immune-mediated complications. However, routine interference with these responses is not indicated.
334 citations
TL;DR: Thirteen patients with healthy hearts and lungs, who were scheduled for lower abdominal surgery during isoflurane anaesthesia with muscular paralysis, were investigated with arterial blood gases, spirometry, pulmonary x‐ray and computed tomography of the chest before and during anaesthesia, as well as during the first 4 postoperative days.
Abstract: Thirteen patients with healthy hearts and lungs, and with a mean age of 68 years, who were scheduled for lower abdominal surgery during isoflurane anaesthesia with muscular paralysis, were investigated with arterial blood gases, spirometry, pulmonary x-ray and computed tomography (CT) of the chest before and during anaesthesia, as well as during the first 4 postoperative days. Before anaesthesia, lung function and gas exchange were normal in all patients. Pulmonary x-ray and CT scans of the lungs were also normal. During anaesthesia, 6 of 13 patients developed atelectasis (mean 1.0% of intrathoracic transverse area in all patients). Two hours postoperatively, 11 of 13 patients had atelectasis and the mean atelectatic area was 1.8%. Pao2 was significantly reduced by 2.1 kPa to 9.8 kPa. On the first postoperative day, the mean atelectasis was unaltered (1.8%). None of the atelectasis found on CT scanning could be detected on standard pulmonary x-ray. Forced vital capacity (FVC) and forced expired volume in 1 s (FEV1) were significantly decreased to 2/3 of preoperative level. Pao2 was significantly reduced to less than 80% of the preoperative level (mean 9.4 kPa). There were significant correlations between the atelectatic area and the impairment in FVC, FEV1, and Pao2. Spirometry and blood gases improved during the succeeding postoperative days, and atelectasis decreased. No patient suffered from pulmonary complications, as judged from clinical criteria and pulmonary x-ray, in contrast to the findings of atelectasis in 85% of the patients by computed tomography.
233 citations
TL;DR: Persistent post‐thoracotomy pain lasting for more than 6 months was reported by 44% of the patients, of whom 66% had received treatment for the pain, and the postoperative pain relief was rated as good, satisfactory, satisfactory and poor in 2%.
Abstract: In order to evaluate postoperative pain treatment following thoracic surgery, 214 medical records of patients who were operated during 1986-1988 were examined. Nurses' comments concerning pain and the amounts of analgesics given during the 2 postoperative days were recorded. The 150 patients who were still alive in December 1989 were sent a postal questionnaire which asked about the pain and the efficacy of pain relief they had received after their operation. They were also asked if they still had pain which they connected to the thoracotomy and if any attempts had been made to treat that pain. The mean consumption of intramuscular oxycodone was 38 mg during the 1st and 33 mg during the 2nd postoperative day. The administration of nonsteroidal anti-inflammatory drugs significantly reduced the opioid consumption on the second but not on the first postoperative day. In 30% of the patients' charts there were no remarks on pain, in 10% there was a mention of no pain, in 40% pain was mentioned and in 20% the patient was reported to have severe pain. During the first postoperative week little pain was experienced by 60% of the patients, considerable pain by 35% and excruciating pain by 5% of the patients being interviewed. The postoperative pain relief was rated as good in 60% of the answers, satisfactory in 38% and poor in 2%. Persistent post-thoracotomy pain lasting for more than 6 months was reported by 44% of the patients, of whom 66% had received treatment for the pain.
216 citations
TL;DR: The preservation of functional‐metabolic coupling under a surgical dose of chloralose renders this anesthetic particularly suited for the investigation of coupling processes under conditions where the experimental requirements preclude the use of unanaesthetized animals.
Abstract: The effect of various anesthetics on the functional-metabolic coupling of cerebral cortex was studied in rats submitted to unilateral somatosensory stimulation. The regional cerebral metabolic rate of glucose (CMRglc) was measured autoradiographically using the 2-deoxyglucose method, and somatosensory activation was carried out by electrical stimulation of the left forepaw. In animals treated with 70% nitrous oxide, 0.5% halothane/70% nitrous oxide or 40 mg/kg pentobarbital, CMRglc of somatosensory cortex did not change despite generation of primary evoked cortical potentials. Anesthesia with 80 mg/kg alpha-chloralose, in contrast, led to a focal increase of CMRglc in the primary somatosensory cortex from 52.1 +/- 18.3 to 73.1 +/- 18.9 mumol/100 g/min (means +/- s.d.). Metabolic activation was strictly confined to the forelimb (FL) area of somatosensory cortex, and it exhibited a laminar pattern with maximal activation in layers I, II and IV. The preservation of functional-metabolic coupling under a surgical dose of chloralose renders this anesthetic particularly suited for the investigation of coupling processes under conditions where the experimental requirements preclude the use of unanaesthetized animals.
206 citations
TL;DR: Acupuncture can ease the discomfort while waiting for an operation and perhaps even serve as an alternative to surgery, and in the second part of the study, it was shown that it was possible to maintain the improvements.
Abstract: Purpose: Acupuncture treatment of patients waiting for arthroplasty surgery. Methods: 29 patients with a total of 42 osteoarthritic knees were randomized to two groups. Group A was treated while Group B served as a no-treatment control group. After 9 weeks Group B was treated too. Analgesic consumption, pain and objective measurements were registered. All objective measures were done by investigators who were “blinded” as to Group A & B. In the second part of the study 17 patients (26 knees) continued with treatments once a month. Registration of analgesic consumption, pain and objective measurements continued. Total study period 49 weeks. Results: Comparing Group A to B there was a significant reduction in pain, analgesic consumption and in most objective measures. In Group A + B combined there was an 80% subjective improvement, and a significantly increased knee range movement – an increase mainly in the worst knees. Results were significantly better in those who had not been ill for a long time. In the second part of the study, it was shown that it was possible to maintain the improvements. Conclusions: Acupuncture can ease the discomfort while waiting for an operation and perhaps even serve as an alternative to surgery. Seven patients have responded so well that at present they do not want an operation. (USD 9000 saved per operation).
152 citations
TL;DR: Six variables were found to be significant in predicting complications: high age, major abdominal surgery, emergency surgery, a history of chronic obstructive lung disease, long‐lasting general anaesthesia (≥ 180 min) involving pancuronium, and anaesthesia involving pancakes, in the order given.
Abstract: The aim of this study was to identify risk factors associated with postoperative pulmonary complications. The influence of the anaesthetic technique was evaluated (i.e. general contra regional anaesthesia and long contra intermediately acting muscle relaxants (pancuronium and atracurium)) taking into account the patient's age, the presence or absence of chronic obstructive lung disease (preoperative risk factors), the type of surgery and the duration of anaesthesia (perioperative risk factors). Seven thousand and twenty-nine patients undergoing abdominal, urological, gynaecological or orthopaedic surgery were included in the study. A total of 290 patients (4.1%) suffered from one or more postoperative pulmonary complications. Six thousand and sixty-two patients received general anaesthesia and 4.5% of these had postoperative pulmonary complications. Of the patients admitted to major surgery receiving pancuronium, 12.7% (135/1062) developed postoperative pulmonary complications, compared to only 5.1% (23/449) receiving atracurium (P < 0.05). When stratified for type of surgery and duration of anaesthesia, conventional statistics showed no difference between pancuronium and atracurium as regard postoperative pulmonary complications. However, a logistic regression analysis indicated that long-lasting procedures involving pancuronium entailed a higher risk of postoperative pulmonary complications than did other procedures. In patients having regional anaesthesia, only 1.9% (18/967) developed postoperative pulmonary complications (P < 0.05 compared to general anaesthesia). However, when stratified for type of surgery there was a significantly higher incidence of postoperative pulmonary complications only in patients undergoing major orthopaedic surgery under general anaesthesia, 11.5% compared to 3.6% in patients given a regional anaesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)
151 citations
TL;DR: It is concluded that a mechanical TOF ratio of 0.70 following vecuronium may be associated with an inadequate ventilatory response to hypoxaemia.
Abstract: The effect of a partial neuromuscular block on the ventilatory response to hypercarbia and to hypoxaemia was studied in 11 non-anaesthetized male subjects. Respiratory frequency, tidal volume, minute volume, respiratory timing and drive were measured during air breathing and during stimulation by hypercarbia and hypoxaemia. The ventilatory response was defined as the ratio between, respectively, tidal volume and minute volume during ventilation stimulated by hypercarbia and hypoxaemia compared to measurements during air breathing. The ventilatory measurements were repeated on three separate occasions: before neuromuscular block was established, during an infusion of vecuronium aiming at a mechanical adductor pollicis train-of-four (TOF) ratio of 0.70, and after the infusion had been stopped and the neuromuscular block had spontaneously recovered to a TOF ratio of > 0.90. Resting ventilation during air breathing remained with minor variations throughout the experiment. The ventilatory response to hypercarbia was not affected at a TOF ratio of 0.70 as compared to measurements before vecuronium and at a TOF ratio of > 0.90. In contrast, the ventilatory response to hypoxaemia was markedly reduced at a TOF ratio of 0.70. We conclude that a mechanical TOF ratio of 0.70 following vecuronium may be associated with an inadequate ventilatory response to hypoxaemia.
137 citations
TL;DR: In one patient complications due to barbiturate treatment may have contributed to the fatal outcome and in none of the other cases were the noted complications and side effects associated with any permanent symptoms or dysfunctions.
Abstract: This study reports all complications and side effects occurring in 38 patients with severe traumatic brain lesions treated with barbiturate coma because of a dangerous increase in intracranial pressure. The treatment was induced by intravenous infusion of thiopentone (5-11 mg.kg-1) followed by a continuous infusion of 4-8 mg.kg-1.h-1. The subsequent rate of thiopentone infusion was governed by the level of the intracranial pressure with the intention of keeping ICP below 20 mmHg (2.7 kPa). The duration of treatment was 1-15 days. Arterial hypotension occurred in 58%, hypokalemia in 82%, respiratory complications in 76%, infections in 55%, hepatic dysfunction in 87% and renal dysfunction in 47% of the patients. Twenty patients survived. Mortality in 17 patients was caused by an untreatable increase in intracranial pressure. In one patient complications due to barbiturate treatment may have contributed to the fatal outcome. In none of the other cases were the noted complications and side effects associated with any permanent symptoms or dysfunctions.
132 citations
TL;DR: From the data in the literature, there are no indications of an increased risk in using the combination of low molecular weight heparin in prophylactic doses and epidural/spinal anaesthesia.
Abstract: This article reviews the problem of bleeding in connection with epidural/spinal anaesthesia, with special emphasis on the use of low molecular weight heparins for thromboprophylaxis. There are methodological difficulties to studying the problem in a scientifically correct way because of the rarity of the complication. However, from the data in the literature there are no indications of an increased risk in using the combination of low molecular weight heparin in prophylactic doses and epidural/spinal anaesthesia. So far, there is only a single case report, of spinal haematoma, although low molecular weight heparins have been used in combination with epidural/spinal anaesthesia in at least 1,000,000 patients. In controlled studies, at least 10,000 patients have been given the combination without complications.
124 citations
TL;DR: The results indicate that rocuronium may replace suxamethonium in procedures in which rapid sequence induction is required, and may have a major advantage over existing non‐depolarising muscle relaxants due to the early presence of excellent intubating conditions.
Abstract: The intubating conditions and neuromuscular blocking profile following 600 micrograms.kg-1 rocuronium (Org 9426) have been investigated in patients under various experimental conditions. They were compared with conditions following 1.5 mg.kg-1 suxamethonium, preceded by a precurarising dose (10 mg) of gallamine, and with those in a control group in the absence of a muscle relaxant. Rocuronium produced good to excellent intubating conditions at 60 as well as at 90 s after administration, even though there was only a partial blockade of the adductor pollicis muscle. Intubating conditions following suxamethonium were comparable with those after rocuronium. Half of the control patients could be intubated. The clinical duration and the recovery time of 600 micrograms.kg-1 of rocuronium were 24(4) and 9(3) min (mean(s.d.)), respectively. Rocuronium may have a major advantage over existing non-depolarising muscle relaxants due to the early presence of excellent intubating conditions. The results indicate that rocuronium may replace suxamethonium in procedures in which rapid sequence induction is required.
121 citations
TL;DR: In all the authors' patients interscalene block caused an ipsilateral hemidiaphragm paresis, which in five of ten patients persisted until the end of the continuous block, which provided adequate anaesthesia for surgery or manipulation.
Abstract: Interscalene block may cause phrenic nerve block and decreased diaphragmatic motion. We evaluated the effect of continuous interscalene block on ventilatory function and diaphragmatic motion. We studied ten patients scheduled for surgery or manipulation of the shoulder. Preoperatively, the patients underwent spirometry and double-exposure chest radiography. They received an interscalene block with 0.75% bupivacaine. Thereafter, 0.25% bupivacaine was infused into the interscalene space for 24 h. Spirometry was repeated three times and double-exposure radiography twice. The maximal inspiratory and expiratory pressures were measured repeatedly. Haemoglobin oxygen saturation (SPO2) was monitored with pulse oximetry. The block provided adequate anaesthesia for surgery or manipulation. All patients had a marked ipsilateral paresis of the diaphragm in the radiographs 3 h after the initial block. Twenty-one hours later five patients had diaphragmatic motility comparable to the situation before the block. In the other five patients, the amplitude of diaphragmatic motility on the side of the block was only 4-37% of the values before the block. All patients had a clear reduction in forced vital capacity (FVC), forced expiratory volume in 1s (FEV1) and peak expiratory flow (PEF) 3 and 8 h after the block without signs of dyspnoea. In conclusion, in all our patients interscalene block caused an ipsilateral hemidiaphragm paresis, which in five of ten patients persisted until the end of the continuous block.
TL;DR: It is confirmed that N2O is a potent cerebral vasodilator in man, although the mechanisms underlying the effects on CBF are still unclear.
Abstract: Seven normoventilated and five hyperventilated healthy adults undergoing cholecystectomy and anaesthetized with methohexitone, fentanyl and pancuronium were studied with measurement of cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), and quantified electroencephalography (EEG) under two sets of conditions: 1) 1.7% end-tidal concentration of isoflurane in air/oxygen; 2) 0.85% end-tidal concentration of isoflurane in nitrous oxide (N2O)/oxygen. The object was to study the effects of N2O during isoflurane anaesthesia on cerebral circulation, metabolism and neuroelectric activity. N2O in the anaesthetic gas mixture caused a 43% (P less than 0.05) increase in CBF during normocarbic conditions but no significant change during hypocapnia. CMRO2 was not significantly altered by N2O. EEG demonstrated an activated pattern with decreased low frequency activity and increased high frequency activity. The results confirm that N2O is a potent cerebral vasodilator in man, although the mechanisms underlying the effects on CBF are still unclear.
TL;DR: Two patients with acute severe asthma, who failed to respond to conventional therapy, were given intravenous ketamine in sub‐anaesthetic doses with good results and an infusion at a rate of 0.15 mg/kg/h was used in each case to prevent recurrence of bronchospasm.
Abstract: Two patients with acute severe asthma, who failed to respond to conventional therapy, were given intravenous ketamine in sub-anaesthetic doses with good results. A bolus dose of 0.75 mg/kg was followed by the same dose over 10 min with relief of bronchospasm in both cases. An infusion of ketamine at a rate of 0.15 mg/kg/h was used in each case to prevent recurrence of bronchospasm. Intravenous ketamine can be used to relieve acute intractable bronchospasm provided expert anaesthetic help is at hand. A review of the literature concerning its use in such situations is also presented.
TL;DR: The predictive value of a number of demographic and anesthesiological variables with respect to the three most common complications during spinal anesthesia: hypotension, bradycardia, and nausea was analyzed to create a stepwise logistic regression model.
Abstract: We analyzed the predictive value of a number of demographic and anesthesiological variables with respect to the three most common complications during spinal anesthesia: hypotension, bradycardia, and nausea. A stepwise logistic regression model was created, using data from a prospective study of 1752 patients to combine the predictive value of all entry variables. The highest risk factors for hypotension were: age greater than or equal to 50, a sensory level above Th6, receiving bupivacaine as a local anesthetic, body mass index greater than or equal to 30, and receiving opiate as a premedication. An anesthetic level above Th6 and age below 50 were primarily associated with bradycardia. Females and those with a high sensory level or receiving opiate as a premedication were at significant risk of nausea. The model was also reliably predictive for a separate group of 200 consecutive spinal anesthesia patients. Thus, the risk model may be clinically useful in identifying high-risk patients requiring additional attention.
TL;DR: mTISS is a valuable tool when evaluating resource utilization in the ICU and together with the proposed workload‐index and calculation of costs, mTISS could be used for ICU management control.
Abstract: The Therapeutic Intervention Scoring System (TISS) is an easily applicable method for measurement of workload in the intensive care unit (ICU). In the present study a modified TISS-scoring (mTISS) was performed daily during 1988-1989 on 2693 patients in a general ICU. Of these, 900 could be classified as 'true' ICU-patients (ICU-stay > or = 24 h or TISS > or = 20 points), whereas the rest were postoperative. In ICU-patients the average length of stay was 4.5 +/- 8.9 days and the average workload 114 +/- 218 mTISS-points. The workload was not significantly related to age or type of admission (scheduled vs unscheduled). Hospital non-survivors (13.6%) showed a significantly increased mean total mTISS-score (239 +/- 364, P < 0.001). Critically ill (TISS Class IV) patients (14% of the sample), with an average workload of 437 +/- 401 mTISS-points, consumed 53% of the total resources. Patients categorized (ICD-9) to respiratory and infectious diseases showed the greatest average workload (207 +/- 315 and 208 +/- 355 mTISS-points, respectively). A workload-index was also developed relating the actual workload to the ICU personnel. The cost of each mTISS-point was calculated. In conclusion, the present study showed that mTISS is a valuable tool when evaluating resource utilization in the ICU. Together with the proposed workload-index and calculation of costs, mTISS could be used for ICU management control.
TL;DR: The sufentanil group had much better pain scores, but on exercise these patients experienced more pain than the combination group, and in the combination groups, there were better respiratory results.
Abstract: Analgesia with epidural bupivacaine, sufentanil or the combination was studied in 50 patients who had undergone thoracotomy. During operation all patients received an initial dose of bupivacaine 0.5% with adrenaline 5 micrograms.ml-1 (5-10 ml) by thoracic epidural catheter. One hour later the patients were divided into three groups: the bupivacaine group (bupivacaine 0.125%), the sufentanil group (50 micrograms sufentanil in 60 ml normal saline) and the combination group (50 micrograms sufentanil in 60 ml bupivacaine 0.125%). Analgesia in the three groups was provided by a continuous epidural infusion (5-10 ml.h-1) for 3 days. The mean dose of bupivacaine was significantly higher (P less than 0.05) in the bupivacaine group (12.07 mg.h-1 (s.e.mean 0.97 mg.h-1)), compared with the combination group (9.82 mg.h-1 (s.e.mean 0.43 mg.h-1)). The mean dose of sufentanil in the sufentanil group was similar to the combination group (6.37 micrograms.h-1 (s.e.mean 0.23 micrograms.h-1) and 6.52 micrograms.h-1 (s.e.mean 0.28 micrograms.h-1), respectively. The pain scores on the inverse visual analogue scale of most patients in the bupivacaine group were unacceptably low. The sufentanil group had much better pain scores, but on exercise these patients experienced more pain than the combination group. The combination group had, overall, better pain scores. In the combination group, there were better respiratory results.
TL;DR: It is concluded that propofol allows early discharge of patients, even after long anaesthesias, and was discharged home earlier than patients receiving isoflurane.
Abstract: Fifty unpremedicated patients scheduled for outpatient restorative dentistry and/or oral surgery lasting 2 to 4 h were anaesthetized with either propofol infusion or isoflurane inhalation. Before induction of anaesthesia with propofol (2.5 mg.kg-1), all patients were given 75 mg of diclofenac and 0.01 mg.kg-1 vecuronium intravenously. Intubation was facilitated with suxamethonium (1.5 mg.kg-1) and anaesthesia was maintained in random order either with propofol infusion (12 mg.kg-1.h-1 for the first 20 min, 9 mg.kg-1.h-1 for the next 20 min, and 6 mg.kg-1.h-1 for the rest of the anaesthesia) or with isoflurane (inspired concentration 1-2.5%), both with nitrous oxide and oxygen (30%). The patients breathed spontaneously using a non-rebreathing circuit. Patients given propofol infusion became re-orientated faster (11.0 +/- 5.5 min vs. 16.5 +/- 7.5 min; P less than 0.01) and at 30 min walked along a straight line better (P less than 0.01). At 60 min, none of the propofol patients displayed an unsteady gait, whereas 11 of the 25 isoflurane patients did (P less than 0.001). None of the patients receiving propofol had emesis at the clinic, compared with 10 of the 25 patients receiving isoflurane (P less than 0.001). The overall incidence of emesis was 2 of 25 and 14 of 25 in the propofol and isoflurane groups, respectively (P less than 0.01). Patients receiving propofol were discharged home earlier than patients receiving isoflurane (80 +/- 14 min and 102 +/- 32 min, respectively; P less than 0.01). It is concluded that propofol allows early discharge of patients, even after long anaesthesias.
TL;DR: Premedication with oral clonidine in these elderly patients undergoing elective intraocular surgery produced intraoperative sedation, reduction in anxiety and decrease in intraocular pressure, and postoperative recovery was improved in the cl onidine group.
Abstract: In a randomized double-blind study, the effects of clonidine premedication as a sedative, anxiolytic, analgesic and oculohypotensive agent were studied in 100 elderly patients (62 to 65 +/- 10 years, ASA grade I-II) undergoing elective intraocular surgery under local anaesthesia. The control group (Group A, n = 50) received oral diazepam 0.15 mg/kg 120 min before surgery and Group B (n = 50) received oral clonidine 300 micrograms 120 min before surgery. Two hours after the premedication, there was significantly more sedation (P less than 0.05) and less subjective anxiety (P less than 0.05) in the clonidine group than in the control group. There was a significant fall in intraocular pressure (IOP) from 20 +/- 0.5 to 13 +/- 0.5 mmHg (P less than 0.05) and significant reduction in systolic and diastolic blood pressure (BP) and heart rate (HR) (P less than 0.05) in the clonidine group as compared to the control group. Perioperatively, significantly more supplementation with i.v. diazepam was given in the control group than in the clonidine group (P less than 0.01). The incidence of intra-operative hypertension (P less than 0.01) and tachycardia (P less than 0.05) was significantly greater in the control group than in the clonidine group. A significantly larger number of patients in the clonidine group scored a Post-Anaesthesia Recovery (PAR) score of 10 as compared to the control group (P less than 0.01). There was no statistical difference in the postoperative Visual Analogue Scale (VAS) scores for pain, number of analgesic requests and emesis.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: i.m. alfentanil is well tolerated, and its anxiolytic and short sedative effects make it especially suitable as premedication for day‐case cataract surgery.
Abstract: The effects of i.m. alfentanil and midazolam on anxiety, sedation, hemodynamics, oxygen saturation and intraocular pressure were studied in 90 patients scheduled for outpatient cataract surgery with regional anesthesia. The study was randomized, double-blind, placebo-controlled, and performed on outpatients with ASA physical status I-III and mean age 67.7 +/- 11.7 years. Alfentanil (12.5 micrograms/kg) administered into the deltoid muscle had a marked anxiolytic and short sedative effect, and was associated with stable hemodynamics. Midazolam (20 micrograms/kg) administered similarly had a more prolonged anxiolytic and sedative effect, which impaired co-operation in some patients during surgery. The regional blockade was associated with a significant reduction of oxygen saturation (SpO2), regardless of the premedication used (P less than 0.05). A slight reduction of intraocular pressure (IOP) was found after premedication, but the change was not statistically significant. We conclude that i.m. alfentanil is well tolerated, and its anxiolytic and short sedative effects make it especially suitable as premedication for day-case cataract surgery.
TL;DR: It is suggested that induction of anaesthesia with propofol followed by maintenance with isoflurane in oxygen and air during spontaneous ventilation is associated with rapid psychomotor recovery and is a suitable method for ambulatory surgery.
Abstract: This study compares psychomotor recovery following induction of anaesthesia with either thiopentone or propofol in 30 healthy, unpremedicated patients undergoing outpatient arthroscopic procedures of the knee. A battery of tests including simple reaction time (SRT), choice reaction time (CRT), perceptive accuracy test (PAT) and digit symbol substitution test (DSST) were done before anaesthesia. The patients were randomly divided into two groups: Group 1 was induced with thiopentone 5-6 mg/kg while Group 2 was induced with propofol 2-3 mg/kg. Anaesthesia was then maintained with isoflurane (0.5-2%) in oxygen and air, and supplements of alfentanil were given for analgesia during spontaneous respiration with a face mask. Psychomotor recovery assessed every 30 min postoperatively for 120 min showed that patients in Group 1 had not returned to baseline values until 120 min after the operation on the PAT, while those in Group 2 had returned to baseline values at 60 min. No patient had any significant side effects. The SRT, CRT and DSST proved to be relatively insensitive in the detection of residual effects of anaesthesia and had a significant learning effect. This study suggests that induction of anaesthesia with propofol followed by maintenance with isoflurane in oxygen and air during spontaneous ventilation is associated with rapid psychomotor recovery and is a suitable method for ambulatory surgery. The PAT is sensitive and not associated with some of the problems found with other commonly used tests.
TL;DR: It is concluded that mivacurium is short‐acting in patients with normal pChe phenotype and normal to low‐normal pChe activity, and a prolonged response to mivicurium may, however, be expected in these patients.
Abstract: The significance of plasma cholinesterase (pChe) activity for the duration of action of mivacurium in phenotypically normal patients was evaluated in 35 patients during neurolept anaesthesia. The response to train-of-four nerve stimulation was recorded using a Myograph 2000. Ten patients with normal pChe (Group 1) and five patients with decreased pChe activity (Group 2) were given a small test dose of mivacurium 0.03 mg kg-1. Mivacurium 0.1 mg kg-1 was administered following spontaneous recovery from the first dose. The mean suppression of the height of the first (T1) of the train-of-four responses following mivacurium 0.03 mg kg-1 patients with normal and decreased enzyme activity was 40% and 56%, respectively, and the mean T1 suppression after mivacurium 0.1 mg kg-1 was 100% in both groups. The times to different levels of twitch height recovery following the 0.1 mg kg-1 dose did not differ between the two groups of patients. Another 20 patients with normal or decreased pChe activity (Group 3) were given mivacurium 0.2 mg kg-1. In this group the time to maximum block was 1.4 min (1.0–4.0) mean (range) and the time to reappearance of the T1 response was 15.0 min (7.4–22.7) (range). An inverse relationship was found between the patients' pChe activity and the time to first response. It is concluded that mivacurium is short-acting in patients with normal pChe phenotype and normal to low-normal pChe activity. No patient with very low pChe activity was included in the study. A prolonged response to mivacurium may, however, be expected in these patients.
TL;DR: Intrathecal morphine had no significant effect on ventilatory regulation in elderly patients undergoing major hip surgery performed under bupivacaine spinal analgesia while postoperative administration of opioids or sedatives after intrathecal morphine as well as postoperative blood loss associated with a fall in blood pressure appeared to increase the risk of developing respiratory depression.
Abstract: Thirty elderly patients undergoing major hip surgery under spinal analgesia were randomly allocated in a double-blind manner into three groups. The aim was to evaluate the influence of intrathecal morphine and postoperative naloxone infusion on the regulation of ventilation. The Bupivacaine Group received spinal analgesia with 20 mg bupivacaine intrathecally. The Morphine Group received spinal analgesia with 20 mg bupivacaine + 0.3 mg morphine intrathecally. The Naloxone Group received spinal analgesia with 20 mg bupivacaine + 0.3 mg morphine intrathecally + postoperative naloxone infusion intravenously (1 microgram/kg/h over 12 h, 0.25 micrograms/kg/h over the next 12 h). Evaluation of resting ventilation and the ventilatory responses to hypercarbia and hypoxaemia was made on three occasions: before surgery, and 8, and 24 h after the intrathecal injection. Intrathecal morphine had no significant effect on ventilatory regulation in elderly patients undergoing major hip surgery performed under bupivacaine spinal analgesia. Postoperative administration of opioids or sedatives after intrathecal morphine as well as postoperative blood loss associated with a fall in blood pressure appeared to increase the risk of developing respiratory depression. Naloxone infusion seemed to reduce the risk of developing respiratory depression. Furthermore, one third of the elderly had a poor response to hypoxaemia before surgery.
TL;DR: The present results suggest that isoflurane reduces excitatory synaptic transmission by a presynaptic mechanism.
Abstract: The purpose of this investigation was to study the effect of isoflurane on excitatory synaptic transmission. Rat hippocampal slices maintained in vitro were used as a model. Isoflurane caused a dose-dependent reduction of the excitatory postsynaptic potential (EPSP); 1.5% isoflurane reduced the EPSP by 35 +/- 9% (mean +/- s.d.) and 3% by 57 +/- 11%. Neither spontaneous nor potassium-stimulated efflux of the glutamate analogue D-(3H)aspartate was changed, but the content of D-(3H)aspartate in slices loaded during isoflurane was reduced to 83 +/- 12% of control (P less than 0.05). The intracellularly recorded response to direct application of glutamate increased by 37 +/- 20% during isoflurane (3%) and 50 +/- 5% during halothane (2%). Isoflurane (3%) enhanced the response to the glutamate receptor agonist quisqualate by 44 +/- 19%, whereas the N-methyl-D-aspartate response was unchanged. Isoflurane enhanced the tetanic depression of the population spike. The present results suggest that isoflurane reduces excitatory synaptic transmission by a presynaptic mechanism.
TL;DR: It is concluded that children undergoing strabismus surgery anesthetized with propofol/fentanyl had more episodes of peroperative bradycardia, a lower incidence of postoperative vomiting and a shorter recovery time, and were more apprehensive during the initial postoperative period than children anestetherized with thiopental/halothane.
Abstract: Forty-four children, ASA physical status I or II, aged 1.5-14 years and admitted for strabismus surgery, were studied. The study compared the postoperative condition after two different anesthesia methods. All children were premedicated with midazolam rectally, received glycopyrrolate i.v. and were then randomised to one of two anesthetic methods: 1) induction with thiopental, maintenance with halothane or 2) induction with propofol supplemented with fentanyl, maintenance with propofol infusion. In both groups, tracheal intubation was performed after vecuronium i.v. and the children were ventilated manually. Peroperatively, patients receiving propofol/fentanyl had more episodes of bradycardia (P less than 0.001). Times to spontaneous breathing and extubation were shorter in the propofol/fentanyl group (P less than 0.05) and there was also a lesser degree of sedation during the first 2 h postoperatively (P less than 0.01). Fewer children in the propofol/fentanyl group vomited postoperatively (P less than 0.05). The apprehension score was higher in the propofol/fentanyl group compared to the thiopental/halothane group (P less than 0.05). We conclude that children undergoing strabismus surgery anesthetized with propofol/fentanyl had more episodes of peroperative bradycardia, a lower incidence of postoperative vomiting and a shorter recovery time, and were more apprehensive during the initial postoperative period than children anesthetized with thiopental/halothane.
TL;DR: A double‐blind study to determine the specificity and sensitivity of an epidural test dose to detect inadvertent intravenous injection in obstetric patients undergoing epidural analgesia found the primary investigator to have an excellent specificity and a good sensitivity.
Abstract: A double-blind study was designed in order to determine the specificity and sensitivity of an epidural test dose to detect inadvertent intravenous injection in obstetric patients undergoing epidural analgesia. Forty unselected obstetric patients were given an intravenous injection of 10 ml bupivacaine 0.125% with 12.5 micrograms epinephrine (test dose) or 10 ml normal physiologic saline. The maternal heart rate was monitored by the direct ECG mode of a fetal monitor and registered simultaneously with the tocogram. The primary investigator was blinded to the solution he injected into an antecubital vein. After the injection was given, he recorded his judgment of which solution he had administered. Eight other anesthesiologists made similar judgments on the basis of the recordings plus various levels of additional information (presence or absence of epidural analgesia, time of injection, subjective signs and symptoms). In contrast to the primary investigator, the blood pressure values were not given to them. For the primary investigator, the specificity of the test dose was 100% and the sensitivity 97.5%. The judgments of the 8 other anesthesiologists resulted in an excellent specificity (99.1%) and a good sensitivity (91.9% with information on time of injection and subjective signs and symptoms). The better performance of the primary investigator is probably due to the availability of blood pressure data.
TL;DR: Pretreatment with alfentanil significantly diminished haemodynamic responses to tracheal intubation and caused transient severe bradycardia and a significant decrease in heart rate after laryngoscopy.
Abstract: The effect of pretreatment with alfentanil 10 (Alf10), 15 (Alf15) or 20 (Alf20) micrograms.kg-1 on reducing injection pain caused by propofol was compared with lignocaine 10 mg mixed with propofol (Lign). This double-blind, double-dummy and randomized study included 100 children with a mean age of 4.3 +/- 0.6 years, 25 children in each group, undergoing minor otolaryngological surgery. The children were premedicated orally with midazolam 0.5 mg.kg-1 and atropine 0.03 mg.kg-1. Injection pain occurred in 4% in the Lign group. The corresponding figures were 40, 16 and 20% in the Alf10, Alf15 and Alf20 groups, respectively. Both 1% lignocaine 10 mg and alfentanil 15 micrograms.kg-1 reduced injection pain significantly compared with alfentanil 10 micrograms.kg-1. Pretreatment with alfentanil significantly diminished haemodynamic responses to tracheal intubation. Furthermore, the concomitant use of alfentanil and propofol caused transient severe bradycardia and a significant decrease in heart rate after laryngoscopy.
TL;DR: It is indicated that psychomotor recovery following isoflurane anaesthesia is quicker than that following propofol and choice reaction time showed no significant difference in either group 30 min after the anaesthetic.
Abstract: A newly developed test for the assessment of psychomotor recovery--the perceptive accuracy test (PAT)--is described. Seventy-four subjects who performed the test though that it was easy to perform and some were motivated to try it on a number of occasions. Eight persons performed the test on different days and at different periods of time; the results were consistent and reproducible. Eight more persons were then asked to do the test 4 times at 15-min intervals; no 'learning' was seen with this test. A randomized, prospective study was then performed in two groups of 15 patients, undergoing arthroscopic procedures of the knee. Anaesthesia was induced with propofol and maintained with an infusion of propofol 12 mg/kg/h for the first 15 min, followed by 8 mg/kg/h subsequently in the propofol group. In the isoflurane group, anaesthesia was also induced with propofol, but isoflurane (0.5-2%) was used to maintain anaesthesia. Alfentanil was the analgesic used in both groups of patients. Results were compared with a third group of unanaesthetised controls, who were asked to perform psychomotor tests including choice reaction time and PAT at 30-min intervals for 2.5 h. There was a significant difference (P less than 0.01) in psychomotor recovery on the PAT-200 between the propofol group and control groups, but not in the isoflurane and control groups at 30 min. Both groups had returned to baseline values at 60 min in the PAT-60 and PAT-200. The choice reaction time showed no significant difference in either group 30 min after the anaesthetic.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: The baroreceptor reflex sensitivity was maintained during propofol anaesthesia and the carotid sinus pressure interval at which the maximum changes in MAP could be elicited, was significantly higher during M than during P, indicating resetting of the baroreflex.
Abstract: The effects of propofol (P), methohexitone (M) and isoflurane (I) on the baroreceptor reflex were studied in a cat model in which the blood pressure in a bilateral isolated carotid sinus preparation was artificially varied between 50-200 mmHg. The influence from aortic and cardiopulmonary baroreceptors was excluded by vagotomy. With basal chloralose anaesthesia as control, the investigated anaesthetics were used in doses corresponding to MAC 0.5 and 1.0. The maximum change in systemic mean arterial pressure (MAP) and heart rate (HR) following a defined increase in carotid sinus pressure was used as an index of baroreceptor reflex sensitivity. Compared to control, M and I anaesthesia were associated with significant depression of baroreceptor reflex sensitivity at the high dose (corresponding to MAC 1.0), and during I anaesthesia also at the low dose (MAC 0.5). The baroreceptor reflex sensitivity was maintained during propofol anaesthesia. The carotid sinus pressure interval at which the maximum changes in MAP could be elicited, was significantly higher during M than during P. This indicates resetting of the baroreflex.
TL;DR: The established level of analgesia suggests that the changes in circulatory and hormonal variables as well as successful resuscitation of the subjects with saline in the head‐down position conform to central blood volume depletion leading to increased vagal tone.
Abstract: Pathophysiologic mechanisms of bradycardia during epidural anaesthesia (L3-L4 with 1% lidocaine, 38 ml) were evaluated by studying changes in selected cardiovascular and hormonal parameters. Six of eight subjects (analgesia to T8-T10) remained circulatory stable with no significant changes in heart rate (HR), mean arterial pressure (MAP) and thoracic impedance (TI). In one of two subjects MAP decreased after 25 min from 85 to 50 mmHg (11.3 to 6.7 kPa), HR from 80 to 45 beats · min-1 while thoracic impedance increased from 25.5 to 26.5 ohm. End-systolic diameter (ESD) and end-diastolic diameter (EDD) of the left ventricle determined with echocardiography were reduced from 3.8 to 3.2 cm (17%) and 5.6 to 5.0 cm (11%), respectively. In the other subject MAP decreased after 25 min from 75 to 50 mmHg (10.0 to 6.7 kPa) and HR from 82 to 60 beats · min-1 while thoracic impedance increased from 28.8 to 29.6 ohm. ESD was reduced from 3.8 to 3.3 cm (13%), and EDD from 5.6 to 5.0 cm (11%). Both subjects recovered after infusion of saline and being placed in the head-down position. There were no consistent changes in plasma catecholamines, whereas pancreatic polypeptide increased from 5 and 3 to 152 and 69 pmol·1-1, vasopressin from 3 and 2 to 152 and 46 pmol·1-1, and aldosterone from 282 and 229 to 383 and 485 pmol·-1, respectively. The established level of analgesia suggests that the changes in circulatory and hormonal variables as well as successful resuscitation of the subjects with saline in the head-down position conform to central blood volume depletion leading to increased vagal tone. During epidural anaesthesia presyncopal symptoms were preceded by an approximately 13% reduction in left ventricular diameters.
TL;DR: Repeated small boluses of propofol were administered to ten ASA I patients undergoing carpal tunnel release using regional anaesthesia to maintain conscious sedation or light sleep, and no significant variations in respiratory rate, minute volume, tidal volume, inspiratory and expiratory time, or blood gas analysis were observed.
Abstract: The effects of sedative-hypnotic doses of propofol on respiratory drive and pattern have not yet been extensively described. Repeated small boluses of propofol (0.6–0.3 mg ?˙ k-1) were administered to ten ASA I patients undergoing carpal tunnel release using regional anaesthesia. Airway pressure, capnography and pneumotachography were continuously recorded. With respect to basal values, no significant variations of respiratory rate, minute volume, tidal volume, inspiratory and expiratory time, total expiratory cycle, Ti/Ttot, TV/Ti, P0.1, Etco2 and blood gas analysis were observed. Low doses of propofol, to maintain conscious sedation or light sleep, have not been shown to cause respiratory depression.