Showing papers in "BJA: British Journal of Anaesthesia in 1973"
260 citations
TL;DR: Both the present groups of patients showed significantly attenuated responses of tachycardia and hypertension following laryngoscopy and intubation compared with previous studies and evidence of myocardial ischaemia was significantly lower in beta-blocked patients compared with those who had not received practolol.
Abstract: The effects of intravenous practolol 0.4 mg/kg were studied in 12 hypertensive patients during halothane/nitrous oxide anaesthesia. Practolol decreased heart rate (HR) and cardiac output
\( Q ˙ \) from the elevated levels following atropine administration during anaesthesia, but values of arterial pressure (AP), HR and
Q ˙ after the combination of atropine and practolol were not significantly different from those during anaesthesia prior to blockade. The effects of a similar anaesthetic sequence were studied in a further 11 treated hypertensive patients given practolol by mouth 1.5 mg/kg/6 hours for at least 48 hours preoperatively in addition to current anti-hypertensive therapy. By comparison with treated hypertensive patients previously studied, those pretreated with practolol had similar AP awake, but higher AP throughout anaesthesia with either spontaneous or artificial ventilation. Cardiac output was higher and systemic vascular resistance was lower both before and during anaesthesia. Both the present groups of patients showed significantly attenuated responses of tachycardia and hypertension following laryngoscopy and intubation compared with previous studies. The incidence of dysrhythmia and e.c.g. evidence of myocardial ischaemia was significantly lower (4%) in beta-blocked patients compared with those who had not received practolol (38%).
216 citations
TL;DR: Study of the distribution of ventilation showed that the alveolar/arterial Po2 difference was related to the amount of closure of small airways, which was associated with an alteration in the relationship of functional residual capacity to the volume at which small airway close.
Abstract: SUMMARY Lung function studies were made on a total of 173 patients before and after elective surgery. Functional residual capacity was reduced postoperatively and this reduction was most severe in those patients who underwent an upper abdominal operation. In this group, the postoperative reduction in functional residual capacity was related to the concomitant increase in alveolar/arterial Po2 difference. Studies of the distribution of ventilation showed that the alveolar/arterial Po2 difference was related to the amount of closure of small airways. The increase in alveolar/arterial Po2 difference following upper abdominal surgery was associated with an alteration in the relationship of functional residual capacity to the volume at which small airways close.
156 citations
TL;DR: It is concluded that cortisol is not the prime determinant of blood pressure during and after surgery in glucocorticoid-treated patients, that stress-induced acute adrenocortical insufficiency must be infrequent in these patients, and that an absence of an adrenocortsical response to minor surgery cannot be taken as the sole indication of pathological adrenOCortical function.
Abstract: Adrcnocortical function, as expressed by repeated plasma corticosteroid measurements and the clinical course, were studied in 104 glucocorticoid-treated patients undergoing surgery without supplementary glucocorticoid administration. Eight patients developed otherwise unaccountable hypotension during surgery but only 1 patient showed concomitant low plasma corticosteroid values. Eighteen patients had minimal adrenocortical function without accompanying signs of adrenocortical insufficiency. Postoperatively, 4 patients developed hypotension, which could not be correlated to cortisol deficiency. It is concluded that cortisol is not the prime determinant of blood pressure during and after surgery in glucocorticoid-treated patients, that stress-induced acute adrenocortical insufficiency must be infrequent in these patients, and that an absence of an adrenocortical response to minor surgery cannot be taken as the sole indication of pathological adrenocortical function.
148 citations
TL;DR: With induction of anaesthesia in patients with normal pre-thiopentone pressures, the barbiturate produced no significant alteration in intracranial pressure and the cerebral perfusion pressure remained above 85 mm Hg despite moderate reductions in arterial pressure.
Abstract: Thiopentone was administered in bolus doses (1.5–3.0 mg/kg) 26 times to 18 neurosurgical patients undergoing craniotomy. Intracranial pressure and blood pressure responses to thiopentone were evaluated and the cerebral perfusion pressure calculated. Thiopentone given 21 times to treat chronic or acutely elevated intracranial pressure significantly reduced the mean pressure from 40±1.5 to 22±1.4 mm Hg (±SD). During these 21 treatments the cerebral perfusion pressure increased in 15, remained stable in 2 and decreased in 3. With induction of anaesthesia in patients with normal pre-thiopentone pressures, the barbiturate produced no significant alteration in intracranial pressure and the cerebral perfusion pressure remained above 85 mm Hg despite moderate reductions in arterial pressure. Frequently the action of the short-acting barbiturate in reducing intracranial pressure was transient, being limited, presumably, by redistribution of the drug.
146 citations
TL;DR: The concept of “virtual shunt” is presented as a practical means for determining the optimal inspired oxygen concentration for patients with hypoxaemia due to pulmonary venous admixture, which permits a reduction in the number of blood-gas analyses needed.
Abstract: The concept of "virtual shunt" is presented as a practical means for determining the optimal inspired oxygen concentration for patients with hypoxaemia due to pulmonary venous admixture. The approach permits a reduction in the number of blood-gas analyses needed. Its limitations have been explored and its validity assessed from a series of 44 observations made on 4 patients.
138 citations
TL;DR: Etomidate is the first hypnotic drug for intravenous application which is unlikely to cause chemical histamine release, and changes in the differential blood picture only occurred after Althesin and propanidid; not, however, after etomidate and Cremophor EL.
Abstract: The subject of histamine release was investigated in 16 volunteers by means of plasma histamine determination after the administration of etornidate, Althesin, propanidid, and Cremophor EL. Althesin and propanidid caused release of histamine in various degrees of frequency. Blood pressure changes were rather pronounced with both anaesthetic agents; tachycardia reached its maximum in the first and second minute, which seems to be an argument against histamine release as the underlying cause of this reaction. Histamine was, indeed, only released to such an extent (with the exception of one borderline case) that no clinical symptoms other than secretion of gastric juice and erythema were to be expected. After the application of etomidate and Cremophor EL an increase in plasma histamine was not detectable. Changes in the differential blood picture in terms of a decrease in basophils only occurred after Althesin and propanidid; not, however, after etomidate and Cremophor EL. Etomidate is, therefore, the first hypnotic drug for intravenous application which is unlikely to cause chemical histamine release.
137 citations
TL;DR: It is concluded that nitrous oxide should not be used for induction of anaesthesia in patients with intracranial pathology, because it could be efficiently counteracted by hyperventilation.
Abstract: SUMMARY The effect of induction of anaesthesia with 66% nitrous oxide on intracranial pressure was studied in 12 patients with intracranial disorders. The pressure rose in all cases (mean change 27 mm Hg) to a plateau, which was reached after 5 min. Arterial carbon dioxide tension and arterial blood pressure were essentially unaltered; when measured (4 patients only) central venous pressure was unaffected. Cerebral perfusion pressure decreased on average from 71 mm Hg (range 106-36 mm Hg) to 45 mm Hg (range 71-16 mm Hg). When nitrous oxide was discontinued, intracranial pressure fell immediately to control levels. The most likely mechanism for the intracranial pressure elevation is cerebral vasodilatation leading to increased intracranial blood volume. The consequences may be moderate to marked decrease in cerebral perfusion pressure and, in the diseased brain, focal ischaemia and tentorial herniation. The intracranial hypertension caused by nitrous oxide could be efficiently counteracted by hyperventilation. It is concluded that nitrous oxide should not be used for induction of anaesthesia in patients with intracranial pathology.
126 citations
TL;DR: Clinical improvement following epidural injection for the lumbosciatic syndrome does not appear to be correlated with a wide dissemination of the solution used, and large volumes seem to confer no advantage, and the caudal route perhaps deserves re-evaluation.
Abstract: Radiological evidence of the distribution of solutions in the epidural space indicates that the volume used and the site of injection are the most relevant factors, while the height of the patient is of little importance, and the rate of injection, posture, and age of the patient exert no influence Even so, there are wide variations in spread with a given volume via the same route, and it is impossible to predict accurately the level which will be attained Clinical improvement following epidural injection for the lumbosciatic syndrome does not appear to be correlated with a wide dissemination of the solution used, and large volumes seem to confer no advantage The caudal route perhaps deserves re-evaluation, though the small number in this series prevents valid conclusions being drawn
119 citations
TL;DR: Three new models which incorporate alternative representations of the finite time actually taken have been constructed in terms of Algol programs for a digital computer, showing that the conventional approach causes systematic errors in the computed uptake of low-solubility agents, in the arterial tension of high-soluble agents, and in the tissue tensions of all agents.
Abstract: Conventional compartmental models of the uptake and distribution of inhaled anaesthetics assume that blood moves from lungs to tissues and from tissues back to lungs in zero time. Three new models which incorporate alternative representations of the finite time actually taken have been constructed in terms of Algol programs for a digital computer. It is shown that the conventional approach causes systematic errors in the computed uptake of low-solubility agents, in the arterial tension of high-solubility agents, and in the tissue tensions of all agents. The errors are important in the first minute or two of administration or recovery. The conventional distribution of blood volume between compartments is shown to be in error and to cause even greater systematic errors in computed results. Three different published distributions of tissue volume and cardiac output give different computed results and a "preferred" distribution is suggested.
117 citations
TL;DR: Simple pencil and paper tests of performance were used to measure the state of recovery of patients undergoing intravenous sedation for outpatient dental surgery to distinguish with 80% accuracy patients who were and those who were not as completely recovered as patients who underwent treatment under local analgesia alone.
Abstract: SUMMARY Simple pencil and paper tests of performance were used to measure the state of recovery of patients undergoing intravenous sedation for outpatient dental surgery. Suitable criteria have been devised to distinguish with 80% accuracy those who were and those who were not as completely recovered as patients who underwent treatment under local analgesia alone. Repetition of the test is expected to give an indication of when the individual patient is sufficiently recovered to go home from the outpatient clinic.
TL;DR: Mucus flow at an inspired relative humidity of 100% was comparable to publiched values, and gas introduced at the top of an endotracheal tube at 37°C should have over 50%, and perferably 75%, to maintain tracheal mucus flow.
Abstract: observatons of mucus flow in the trachea were made on greyhounds under barbiturate anaesthesia breathing air at 37°C, at various levels of relative humidity, through an endotracheal tube. The distance travelled by a marker, lycopodium powder, in the mucus was measured at 5-minute intervals throughs a right-angled telescope passed doen the endotracheal tube. Mucus flow at an inspired relative humidity of 100% was comparable to publiched values. No diffrence between flows at inspired relatives humidities of 100% adn 75% was found. A significant reduction in flows at 50% and 25% relatives humidity was found, followed by cessation of flow in 5 of the 7 dogs at 50% relatives humidity, and in all 7 at 25%. This would suggest that gas introduced at the top of an endotracheal tube at 37°C should have a relative humidity of over 50%, and perferably 75%, to maintain tracheal mucus flow. This would correspond to 100% relative humidity at 32°C but it remain to be seen within what temperature rage mucus flow is maintained.
TL;DR: Measurements suggest that satisfactory conditions of lung function obtained when the animals breathed fully saturated air administered at a temperature between 20°C and 30°C.
Abstract: In order to determine the optimal conditions for humidification of inspired air through a tracheostomy, tracheostomized dogs were allowed to breathe humidified air, the temperature of which was deliberately varied between 15°C and 40°C. At 15°C, the air was saturated lower than 40% but was fully saturated at the other temperatures. Measurements of alveolar ventilation, functional residual capacity, lung compliance, alveolar/arterial Po2 difference, pulmonary shunt ratio, cardiac output and oxygen consumption suggest that satisfactory conditions of lung function obtained when the animals breathed fully saturated air administered at a temperature between 20°C and 30°C.
TL;DR: One hundred general surgical patients were subjected to a form of personality assessment the day before operation and the day after surgery, and patients were more “neurotic” (had higher N scores) than the general population; they also had a higher lie (L) score, and this tended to increase with age.
Abstract: One hundred general surgical patients were subjected to a form of personality assessment (Eysenck and Eysenck, 1964) the day before operation. Anaesthesia was standardized using light general anaesthesia, a muscle relaxant and controlled ventilation. The day after surgery patients filled in a standardized postoperative questionnaire about complaints concerning their visit to theatre. The patients were more “neurotic” (had higher N scores) than the general population; they also had a higher lie (L) score, and this tended to increase with age. The N score was greater in those awaiting upper abdominal operations than in those awaiting other procedures, and greater in females than in males. Pain was the most conspicuous postoperative complaint, despite the use of conventional analgesia. Preoperative anxiety was also prominent, as were complaints related to the passage or presence of a nasogastric tube. There was a positive correlation between N score and complaints of anxiety, and between N score and total number of complaints, but not between N score and complaints of pain.
TL;DR: By recording electrical and mechanical effects, it was possible to distinguish clearly the depolarizing blockproduced by suxamethonium from the desensitizing block produced by this agent as well as from the non-depolarizingBlock produced by tubocurarine.
Abstract: In an effort to reconcile conflicting reports in the literature concerning suxamethonium and tubocurarine, we studied the effects of these agents on the adductor pollicis mechanical twitch, adductor pollicis brevis compound action potential and abductor digiti quinti compound action potential. It was observed that the magnitude of block of the adductor pollicis differed from that of the abductor digiti quinti. In addition the magnitude of adductor pollicis block recorded mechanically differed from that recorded electrically. It was further observed that the presence or absence and magnitude of fade and post-tetanic potentiation depended upon the muscle studied, the rate of stimulation, the anaesthetic technique employed, the degree of block and whether electrical or mechanical responses were recorded. Nevertheless, by recording electrical and mechanical effects, it was possible to distinguish clearly the depolarizing block produced by suxamethonium from the desensitizing block produced by this agent as well as from the non-depolarizing block produced by tubocurarine.
TL;DR: In every patient the core temperature rose without any initial after-drop and the suggestion made that it might be applicable in rescue work, in the treatment of elderly hypothermic patients, and in combating accidental hypothermia in the operating theatre.
Abstract: SUMMARY Eleven hypothermic patients were treated by heat supplied via the airway. Three patients died during rewarming, three died of unrelated causes several days after successful rewarming and five survived. Core temperatures were measured by a low reading mercury rectal thermometer and by a thermistor probe inserted into the rectum or mid-oesophagus. In every patient the core temperature rose without any initial after-drop. The problems of the method are discussed and the suggestion made that it might be applicable in rescue work, in the treatment of elderly hypothermic patients, and in combating accidental hypothermia in the operating theatre.
TL;DR: One hundred and fifty-five patients who had spontaneous deliveries, and 32 delivered by forceps or ventouse, were interviewed for up to 6 days postpartum, to discover the incidence of backache, headache, and bladder disturbance.
Abstract: One hundred and fifty-five patients who had spontaneous deliveries, and 32 delivered by forceps or ventouse, were interviewed for up to 6 days postpartum, to discover the incidence of backache, headache, and bladder disturbance. The questionnaire was identical to that used for patients delivered under epidural block. The incidence of backache was 40% for spontaneous deliveries, 25% for forceps/ventouse; headache was 22.3% and 25% respectively, and bladder dysfunction 14.2% and 37.5% respectively.
TL;DR: One hundred consecutive reports of reactions to intravenous anaesthetics Althesin, thiopentone and Epontol are reviewed and analysed and the incidence of reactions is estimated as between one in 11,000 and one in 19,000.
Abstract: One hundred consecutive reports of reactions to intravenous anaesthetics Althesin, thiopentone and Epontol are reviewed and analysed. Ten reactions are attributed to causes other than the anaesthetic drug, and four are believed to have been caused by the muscle relaxant employed. The remaining 86 reactions were grouped according to their clinical presentation: histaminoid reactions ( 19), histaminoid with bronchospasm (33), bronchospasm (12), cardiovascular collapse (uu), delayed histaminoid reactions (6), and clonic contractions (5). None of the first four reaction types was associated with only one anaesthetic. A knowledge of the sales of Althesin has allowed the incidence of reactions to be estimated as between one in 11,000 and one in 19,000.
TL;DR: Haemodynamic studies were made in five patients receiving sodium nitroprusside by intravenous infusion for controlled hypotension during nitrous oxide/halothane anaesthesis, with marked falls in arterial pressure, peripheral resistance and central venous pressure.
Abstract: SUMMARY Haemodynamic studies were made in five patients receiving sodium nitroprusside by intravenous infusion for controlled hypotension during nitrous oxide/halothane anaesthesis. There were marked falls in arterial pressure, peripheral resistance and central venous pressure. Heart rate and cardiac output rose while stroke volume was little changed. All parameters returned quickly to control values on discontinuation of sodium nitroprusside administration.
TL;DR: The results of this study show that 0.3 molar sodium citrate is a successful prophylactic agent in reducing the acidity of gastric contents and is especially suitable for single-dose use in emergency situations where long-term proplylactic measures have not been practised.
Abstract: The antacid properties of 0.3 molar sodium citrate have been studied. Aniseed-flavoured sodium citrate has been used as an oral antacid in 22 patients undergoing general anaesthesia for emergency obstetric procedures. The results of this study show that it is a successful prophylactic agent in reducing the acidity of gastric contents. It is especially suitable for single-dose use in emergency situations where long-term prophylactic measures have not been practised.
TL;DR: The patient's neuroticism score warrants greater attention in studies of postoperative pain, as it is likely to have less pain, less impairment of pulmonary vital capacity and a lower incidence of post operative complications.
Abstract: SUMMARY In 50 male patients the relationship was assessed between preoperative factors, including personality and pain threshold, and postoperative pain and pulmonary changes. There were highly significant correlations between neuroticism scores and postoperative changes. Patients with a low neuroticism score were likely to have less pain, less impairment of pulmonary vital capacity and a lower incidence of postoperative complications. Analysis of extraversion scores was less conclusive. A high psychoticism score was associated with a high neuroticism score, but psychoticism did not otherwise affect the results. There was no significant correlation between preoperative pain threshold and postoperative factors. The analyses of the effect of the non-psychological preoperative factors on postoperative pain severity and pulmonary complications showed less significant results than those with neuroticism. Pulmonary complications were higher in those patients with pre-existing chest disease and the incidence of postoperative pain appeared lower in those patients who had received intraoperative analgesia. Close correlation was found between the postoperative subjective assessment of pain and vital capacity impairment. The patient's neuroticism score warrants greater attention in studies of postoperative pain.
TL;DR: There was a significant correlation between the subjective pain assessment score and postoperative vital capacity impairment and the neuroticism scores showed significant relationships with the vital capacity impairments at 24 hours and the chest complication scores.
Abstract: Preoperative factors, including the assessment of personality and pain threshold, were measured and the relationships between them and severity of postoperative pain and pulmonary complications were investigated in 50 female patients undergoing elective cholecystectomy. The neuroticism scores showed significant relationships with the vital capacity impairments at 24 hours and the chest complication scores. The correlation between neuroticism scores and the subjective pain assessments showed only a trend, but the lie scores and the subjective pain assessments were interrelated. Although pre-existing chest disease affected the incidence of postoperative chest complications, other measured preoperative factors showed little influence on postoperative progress. There was a significant correlation between the subjective pain assessment score and postoperative vital capacity impairment. The personality factors, neuroticism and lie score, should be measured and considered in future studies on postoperative pain and pulmonary complications.
TL;DR: Anesthesia provided by ketamine hydrochloride was employed on 160 occasions in 10 children undergoing 183 attempted radiotherapy treatments to overcome the difficulties of providing adequate sedation and anaesthesia without the presence of the anaesthetist inside the irradiation area.
Abstract: SUMMARY Anaesthesia provided by ketamine hydrochloride was employed on 160 occasions in 10 children undergoing 183 attempted radiotherapy treatments to overcome the difficulties of providing adequate sedation and anaesthesia without the presence of the anaesthetist inside the irradiation area. Ketamine was found to be safe, satisfactory and predictable, lasting for the relatively short time required for such procedures. No serious side effects have been encountered during or after administration. The importance of pre-dictability of action with reference to the routine, continuity and rapid patient-turnover required in a radiotherapy department is stressed.
TL;DR: It is concluded that suxamethonium is the most important agent for the release of creatine phosphokinase from muscle during anaesthesia.
Abstract: SUMMARY Serum creatine phosphokinase was estimated at induction and 24 hours postoperatively in 79 children undergoing ophthalmic operations. The children received the following five anaesthetic sequences: (1) halothane-suxamethonium-halothane; (2) thiopentone-suxa-methonium-halothane; (3) diethyl ether-suxamethonium-halothane; (4) halothane alone; (5) diethyl ether alone. Each group of patients receiving suxamethonium showed a significant rise in serum creatine phosphokinase while groups in which suxamethonium was omitted failed to show significant change. It is therefore concluded that suxamethonium is the most important agent for the release of creatine phosphokinase from muscle during anaesthesia. The anaesthetic induction agents used before suxamethonium influenced this release to a certain extent. Halothane in particular increased it. The possible relationship between changes in serum creatine phosphokinase and malignant hyperthermia is discussed.
TL;DR: The most informative set of components in respect of the acid-base state of the infants appeared to be heart rate and muscle tone and reflex irritability.
Abstract: SUMMARY An analysis of the relationship between the individual components of the 1 min Apgar score, and of each of them with the acid-base status of the infant at delivery, is presented. It is based upon data from four groups of cases: Caesarean section (188), vaginal deliveries conducted under lumbar epidural block (54), and vaginal deliveries without epidural block, the mothers having received no narcotics during labour (84) or having received narcotics during the 6 hours before delivery (85). All the scores were found to be very closely related, the score for colour having the weakest links with the remainder. Each of the component scores, with the exception of that for colour, correlated well with the values for pH, Pco2and base excess in umbilical artery blood, and depressant drugs given before delivery appeared not markedly to influence the degree of correlation. The most informative set of components in respect of the acid-base state of the infants appeared to be heart rate and muscle tone and reflex irritability. Inclusion of the score for colour reduces the discriminatory value of the total score. A similarly-directed analysis of the 5 min score was found to be unproductive because of the small number of imperfect scores.
TL;DR: The results of the trial suggest that in these doses the three drugs were almost equipotent in sedative effect whilst lorazepam showed appreciably better anterograde amnesia for the day of operation.
Abstract: One hundred and fifty-six patients undergoing both major and minor gynaecological and oral surgery were given premedication with either lorazepam 3 mg, heptabarbitone 400 mg or diazepam 10 mg in a double-blind, between-patient investigation. The results of the trial suggest that in these doses the three drugs were almost equipotent in sedative effect whilst lorazepam showed appreciably better anterograde amnesia for the day of operation. Both lorazepam and diazepam caused significazepam antly fewer preoperative side effects than heptabarbitone. The incidence of postoperative nausea and vomiting differed insignificantly between the three groups. Lorazepam in a dosage of 3 mg, given orally 60–180 minutes before anaesthesia proved an effective premedicant.