[Free airway and intubation].
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Airway Obstruction↗
Biomedical subjects
T Randell
Publications and source records attributed to T Randell.
[An intoxicated patient and anesthesia].
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Alcohol Withdrawal Delirium↗
Comparison between the Ovassapian intubating airway and the Berman intubating airway in fibreoptic intubation.
The most common indication for employing the fibreoptic technique for intubation is when a difficult intubation is anticipated. It may also be used when intubation unexpectedly proves difficult with a rigid laryngoscope in anaesthetized patients. However, failures with orotracheal fibreoptic intubation have been reported in up to 9.5% of cases, although only two possible equipment related causes of intubation difficulties have been identified. The Berman intubating airway and the Ovassapian intubation airway in fibreoptic orotracheal intubation have been compared in 65 patients. The study was randomized and for fibreoptic endoscopy each patient served as his or her own control. The results indicate that both airways can be used for orotracheal fibreoptic intubation in anaesthetized patients. The Berman airway offers easier visualization of the vocal cords than the Ovassapian airway, provided that the Berman airway is of an adequate size and positioned in the midline. Upon impingement of the intubation tube, completing the tracheal intubation is more difficult with the Berman airway than the Ovassapian airway.
Adult↗
Orotracheal fibreoptic intubation in children under general anaesthesia.
Orotracheal fibreoptic intubation under general anaesthesia in children was studied in eleven consecutive patients of three months to eight-years-of-age without anticipated intubation difficulties. One case report is also included. Three fibrescopes with a different diameter were used in the study. The fibrescope used was chosen so that it fitted snugly in the tracheal tube. The fibreoscopy was prolonged in one patient due to mucus and two tries were needed. Resistance to the tracheal tube upon intubation was encountered in five patients, only one of these patients was older than two years. Fibreoptic intubation succeeded in nine patients. Two patients were intubated with the Macintosh laryngoscope. The problems encountered in children during orotracheal fibreoptic intubation under general anaesthesia are the same as with adults: easy fibreoscopy is not always followed by easy tracheal intubation, there may be prolonged fibreoscopy and failed intubations. Manipulation of the tracheal tube can lead to successful tracheal intubation and resistance to the tube is more common in smaller children.
Anesthesia, General↗
The effect of patient positioning on dynamic lung compliance.
BACKGROUND: Side-stream spirometry offers a non-invasive method to monitor continuously respiratory mechanics in intubated patients. We studied the effects of different positions on dynamic lung compliance during anaesthesia. METHODS: The study consisted of 56 patients, operated in supine, prone, kneeling or lateral park-bench position. Dynamic lung compliance and inspiratory peak pressure were recorded after induction of anaesthesia, 15 min and 1 h after posturing the patient. RESULTS: The first measured compliances were comparable in all groups. The compliance in the lateral and the prone positions was significantly lower than in the supine position at 15 min (P < 0.01) and 1 h (P < 0.001) after the posture change. The peak inspiratory pressure was significantly lower in the kneeling position than in the other groups (P < 0.01 at the first measurement, P < 0.001 at the later measurements). No correlation was found between body mass index and compliance. CONCLUSION: We found that dynamic lung compliance decreased significantly upon change of posture from supine to lateral or prone position, whereas in the kneeling position no change in compliance was observed. We suggest that the kneeling position might be preferable to the prone position.
Adult↗
Interstitial radiotherapy of 25 parasellar/clival meningiomas and 19 meningiomas in the elderly. Analysis of short-term tolerance and responses.
I-125 seeds were permanently implanted into 25 parasellar-clival meningiomas (median age of patients, 56 y) and 19 globoid meningiomas in the elderly (median age of patients, 77 y) using stereotactic technique and 3-D dose planning. Total dose at the tumour margin was increased during the series from 100 Gy to 150 Gy. The procedure caused no mortality and no serious bleeding, but injury to the III cranial nerve due to puncture occurred in one (4%) of the 25 parasellar-clival meningiomas. In two (4.5%) of the 44 cases the postoperative CT scan showed a misplaced seed, located at the tumour surface. Nonenhancing hypodense rings developed around the seeds ('hot spots') with a median diameter of 10.5 mm at 12 months corresponding to a median initial activity of 8.7 mCi. In general, meningiomas responded by slow reduction in volume. The parasellar-clival meningiomas were followed-up for a median of 19 months (6-32), and so far 4 tumours have shrunk moderately, 13 slightly, and 5 not at all. Pre-operative III, V or VI cranial nerve signs were present in 17 patients and subsided in 8 of them. On the other hand, facial numbness developed or increased in 9 of the 25 patients, indicating that the V nerve is rather sensitive to this type of irradiation. In the 19 meningiomas of the elderly, the median follow-up time was 14 months (5-26). The median relative tumour volume was 46% at 12 months. Accounting for tumour-related deaths only, the actuarial survival rate was 78% at 12 months and 62% at 24 months. In general, brain oedema persisted despite reduction in tumour volume. Stereotactic implantation of I-125 seeds into intracranial meningiomas is relatively safe. Interstitial radiotherapy represents a potential tool in the control of medium-sized intracranial meningiomas with minimal brain oedema, but its long-term impact and untoward effects remain to be followed-up.
Adult↗
Comparison of the effects of controlled ventilation with 100% oxygen, 50% oxygen in nitrogen, and 50% oxygen in nitrous oxide on responses to venous air embolism in pigs.
In this randomized, experimental study in 18 pigs, we have investigated the effects of inspiratory air in oxygen, 100% oxygen and 50% nitrous oxide in oxygen on the detection and consequences of venous air embolism. Each animal was tested with injections of 1.0 ml kg-1 and 2.0 ml kg-1 of air. All animals, except one in the nitrous oxide group, survived the air emboli. Systolic and diastolic arterial pressures decreased significantly in all groups after both injections of air. Pulmonary diastolic pressures increased most in the nitrous oxide group. End-tidal concentration of carbon dioxide decreased significantly in all groups after air injections. The difference in concentration of oxygen in the inspiratory and expiratory gas (O2 (I-E)) was lowest in the air group after both injections of air. On the basis of our studies we suggest that nitrous oxide should not be used during surgery associated with an increased risk of venous air embolism.
Anesthetics, Inhalation↗
Prediction of difficult intubation.
The incidence of a difficult laryngoscopy or intubation varies from 1.5% to 13%, and failed intubation has been identified as one of the anaesthesia-related causes of death or permanent brain damage. Problems in the airway management can be predicted based on previous anaesthesia records, the medical history of the patient and a physical examination. Several radiological measurements have been reported to be associated with a difficult intubation. The sensitivities of the commonly used bedside tests i.e. the Mallampati classification and the thyromental distance have been reported to be from 42% to 81%, and from 62% to 91%, respectively. The figures for the specificity have varied from 66% to 84% and from 25% to 82%, respectively. The other subjective assessments and objective measurements employed for the prediction of a difficult intubation reach comparable sensitivities and specificities. Evidently, the positive predictive value is improved, if combinations of tests are used.
Anesthesia↗
The effect of dextran infusion on antithrombin III concentrations and on platelet function during minor surgery.
The effects of dextran on the antithrombin (AT) III activity and blood coagulation, evaluated with thromboelastography, were investigated in 26 patients (anaesthesia risk class I or II) scheduled for minor surgery under general anaesthesia. In the Dextran group the patients were infused first with dextran 7 ml/kg, then with Ringer's acetate. In the Ringer group, the patients received only Ringer's acetate. In the recovery room fluid therapy was continued with 5% dextrose in water until the first postoperative day. Blood loss and fluid replacement were comparable in the groups. Haematocrit (Hcr) decreased significantly in the Dextran group, and the platelet count decreased in both groups during surgery. The median baseline AT III values were similar in the study groups. In the recovery room, the median AT III value was lower in the Dextran than in the Ringer group, 78% and 92%, respectively (P < 0.05). By the following day, the AT III values had returned near the initial level. After surgery, the maximal amplitude of thromboelastogram was 48 mm in the Dextran group, and 58 mm in the Ringer group (P < 0.05). In conclusion, fluid replacement with dextran resulted in modest and short-lived alterations in blood coagulation.
Adult↗
Monitoring lung compliance and end-tidal oxygen content for the detection of venous air embolism.
Venous air embolism (VAE) is a recognized complication of surgery performed with the patient in the sitting position, but it occurs also during other operations. We report two cases of VAE, associated with a notable decrease in dynamic lung compliance, detected by side-stream spirometry. Based on these cases, an experiment with 10 pigs was designed to evaluate the usefulness of side-stream spirometry in the diagnosis of VAE. Three doses of air (0.5, 1.0 and 2.0 ml kg-1) were injected via the proximal part of a 5- French gauge pulmonary artery catheter. Only the largest dose was followed by haemodynamic deterioration. Significant increases in end-tidal oxygen content and decreases in dynamic lung compliance were detected with all doses of air together with conventional signs of VAE, that is increases in pulmonary artery pressures and arterial carbon dioxide tensions, and decreases in end-tidal concentration of carbon dioxide. We conclude that continuous monitoring of end-tidal oxygen concentration and side-stream spirometry offers valuable supplements to other monitoring techniques in the detection of VAE.
Adult↗
Comparison between two fibrescopes with different diameter insertion cords for fibreoptic intubation.
Two fibreoptic bronchoscopes with insertion cords of different diameters (3.7 and 5.0 mm) were compared during fibreoptic intubation in 84 adult patients (ASA 1-2) undergoing orotracheal intubation under general anaesthesia. The fibrescope used was randomly selected. The incidence of resistance to passage of the tracheal tube through the vocal cords was higher using the thinner fibrescope, 14/40 (35%) as compared with the thicker fibrescope, 5/44 (11%) (p < 0.05). Intubation failed with the thinner fibrescope in 8/40 (20%) of patients, whereas all intubations with the thicker fibrescope were successful in six patients after manipulation of the tracheal tube (p < 0.01). With the thinner fibrescope manipulation of the tracheal tube after impingement led to intubation of the trachea in 6/14 (43%) patients. The duration of intubation was significantly shorter with the thicker fibrescope (p < 0.05). There were two instances of oesophageal intubation with the thinner fibrescope. A fibrescope with a thicker insertion cord is more suitable for orotracheal fibreoptic intubation in adult patients.
Adult↗
Anaphylactoid skin reactions after intravenous regional anaesthesia using 0.5% prilocaine with or without preservative--a double-blind study.
Methylparaben, the preservative of various local anaesthetic solutions, is a potential allergen. In a double-blind study, 0.5% prilocaine with (Citanest, n = 100) or without (n = 100) methylparaben were compared for the occurrence of skin reactions after intravenous regional anaesthesia of the arm in surgical patients. Skin reactions were registered after the deflation of the tourniquet cuff, and intradermal tests were performed with 0.5% prilocaine, 0.1% methylparaben and saline in all patients. Seventeen patients in the Citanest group and four patients in the methylparaben-free prilocaine group developed erythematous skin reactions in the exposed arm after deflation of the tourniquet cuff (P < 0.05, between the groups). The skin symptoms disappeared within an hour and were always restricted to the region which had been anaesthetised. None of the affected patients had positive intradermal tests. The observed skin reactions are probably non-IgE-mediated anaphylactoid reactions in which the presence of methylparaben in the local anaesthetic solution plays a major role.
Adult↗
Fibreoptic intubation and bronchofibrescopy in anaesthesia and intensive care.
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Anesthesia↗
Modifying fluoroscopic views reduces operator radiation exposure during coronary angioplasty.
OBJECTIVES: This three-part study examined the feasibility of reducing operator radiation exposure during coronary angioplasty. BACKGROUND: As case loads and complexity increase, some cardiologists are receiving increasing radiation scatter doses. Techniques to reduce this are therefore becoming more important. METHODS: First, the determinants of the operator dose were assessed by measuring the differences in scatter dose with different camera views. The relative contribution of fluoroscopy as opposed to cine was then quantified. Finally, operators were provided with these data, and subsequent changes in technique were evaluated. RESULTS: Left anterior oblique views resulted in 2.6 to 6.1 times the operator dose of equivalently angled right anterior oblique views. Increasing steepness of the left anterior oblique view also resulted in a progressive increase in operator dose, with left anterior oblique 90 degrees causing eight times the dose of left anterior oblique 30 degrees and three times that of left anterior oblique 60 degrees. In the 45 coronary angioplasty cases prospectively analyzed, fluoroscopy was found to be a greater source of total radiation than cine by a 6.3:1 ratio (range 1.1 to 15.8). Once operators were made aware of the importance of left anterior oblique fluoroscopy, there was a marked reduction in its use. When this was not feasible, there was a reduction in the steepness of the angulation. Left anterior oblique fluoroscopy during angioplasty of the left anterior descending and circumflex coronary arteries was reduced from 40% of total screening time to approximately 5%, and left anterior oblique angulation for fluoroscopy during angioplasty of the right coronary artery decreased from 43.6 degrees (+/- 9.1 degrees) to 29.4 degrees (+/- 2.2 degrees). Success rates (90% vs. 89%) and screening times (19.5 vs. 20.7 min) remained unchanged in 200 coronary angioplasties performed after the study. Average operator radiation dose (measured by radiation badges worn under lead at waist level) was reduced from 32.6 to 14.3 microSv/operator per week despite a slight increase in case load. CONCLUSIONS: Fluoroscopy is the major source of total radiation exposure during coronary angioplasty, with left anterior oblique views providing the highest dose. Modification of views is feasible and will result in significant reduction of operator radiation dose.
Angioplasty, Balloon↗
Glycopyrronium prolongs topical anaesthesia of oral mucosa and enhances absorption of lignocaine.
We have studied the effect of glycopyrronium on the anaesthetic action and absorption of topical lignocaine in 10 healthy, non-smoking volunteers. Lignocaine 100 mg was sprayed on the oral mucosa 15 min after random administration of glycopyrronium 4 micrograms kg-1 or normal saline i.v. Glycopyrronium decreased the mean analgesia score from 2 to 0.1 (2 = baseline; 0 = anaesthesia) at 4 min compared with a change from 2 to 0.5 after normal saline (P < 0.05). All scores returned to baseline by 40 min and 20 min in the glycopyrronium and control groups, respectively. The mean (SD) peak plasma lignocaine concentration was 0.57 (0.29) microgram ml-1 after glycopyrronium and 0.31 (0.10) microgram ml-1 after saline (P < 0.05) and were attained in 17 min (range 10-40 min) and 29 min (range 8-40 min), respectively. Pretreatment with glycopyrronium enhanced absorption and prolonged the analgesic action of topically administered lignocaine.
Absorption↗
Haemodynamic and catecholamine responses to induction of anaesthesia and tracheal intubation: comparison between propofol and thiopentone.
We have studied the haemodynamic changes, QT intervals and catecholamine responses to induction of anaesthesia and tracheal intubation in 24 ASA I patients allocated randomly to receive either propofol 2.5 mg kg-1 or thiopentone 5 mg kg-1 over 60 s. After disappearance of the eyelash reflex, the lungs were ventilated with 100% oxygen for 3 min. The trachea was intubated after administration of vecuronium. With thiopentone, heart rate (HR) was greater than with propofol before intubation (P < 0.05). During induction, systolic (SAP) and diastolic arterial pressure (DAP) decreased more with propofol than with thiopentone. The QT interval was prolonged only during induction with thiopentone. In both groups, HR, SAP, DAP and the QT were increased in response to intubation (P < 0.001). The SAP and QT interval responses to intubation were significantly greater with thiopentone than with propofol (P < 0.05). One patient in the thiopentone group with a significantly prolonged QT interval had episodes of bigeminy and ventricular tachycardia. In both groups, concentrations of noradrenaline in mixed venous plasma increased after intubation (P < 0.001). Concentrations of adrenaline increased after intubation only in the thiopentone group (P < 0.001).
Adolescent↗
Increases in hemodynamic variables and catecholamine levels after rapid increase in isoflurane concentration.
BACKGROUND: Ventilation of the lungs with isoflurane in nitrous oxide and oxygen has been shown to increase the plasma concentration of norepinephrine. Whether this increase is related to the tachycardia and increased arterial blood pressures, seen following a sudden increase in the concentration of isoflurane, was tested in humans. METHODS: Twenty-two healthy patients in whom the trachea was intubated were given 15 min of stable isoflurane-O2-air anesthesia [end-tidal concentration of isoflurane (ETIso) of 1.3%] (baseline). Patients were then randomly allocated to one of two groups. For 13 "IsoHigh" patients, the inspired concentration of isoflurane was increased abruptly. In those patients, the ETIso was kept at 2.6% for 10 min, i.e., until the end of the study, after which the depth of anesthesia was reduced. For nine "IsoLow" control patients, the ETIso level of 1.3% was continued until the end of the study. Heart rate, arterial pressures, catecholamine levels, and end-tidal concentration of CO2 were recorded at baseline and at 1, 1.5, 2, 4, 6, and 10 min after increase in isoflurane. RESULTS: IsoHigh patients showed significant increases in heart rate (40% from 84.6 to 118.1 beats/min), systolic arterial pressure (SAP, 23%, from 96.4 to 118.3 mmHg), and diastolic arterial pressure (DAP, 30%, from 53.9 to 70.0 mmHg); all three variables peaked at 2 min. Significant increases occurred also in norepinephrine levels (80%, from 0.342 to 0.615 ng/ml) and in end-tidal concentration of CO2 (from 4.22% to 4.43%), both of which peaked at 4 min. Epinephrine levels did not increase significantly, although significant differences were seen between IsoHigh and IsoLow patients during the trial. IsoLow patients had no changes in these variables. CONCLUSIONS: A sudden increase in isoflurane concentration is associated with a transient but clinically significant increase in heart rate, arterial pressures, and norepinephrine concentration.
Adult↗