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Biomedical subjects

K Korttila

Publications and source records attributed to K Korttila.

At least 91 records · Page 5Linked to original sources

Pain on i.v. injection of propofol (ICI 35 868) in emulsion formulation. Short communication.

Pain on injection of three anaesthetic induction agents, thiopentone, methohexitone and propofol (diisopropyl phenol), administered into a vein on the dorsum of the hand or wrist, was studied in 32 premedicated patients undergoing elective surgery. The pain was rated as none, mild or severe. A 1% emulsion formulation of propofol (ICI 35 868) (2 mg kg-1) and methohexitone (2 mg kg-1) induced pain significantly more often, in 100% and 80% of patients, respectively, than thiopentone (4 mg kg-1), 0%. The pain was rated as severe more often in patients receiving propofol (67%, P less than 0.01 vs thiopentone) than in those anaesthetized with methohexitone (20%) or thiopentone (0%). It is concluded that the fat emulsion form of propofol, when injected into a peripheral vein, frequently induces severe pain.

Anesthetics↗

Comparison of methohexitone and propofol ('Diprivan') for induction of enflurane anaesthesia in outpatients.

In 73 unpremedicated patients scheduled for minor outpatient oral surgery or restorative dentistry, enflurane anaesthesia was induced either with an emulsion formulation of propofol (2.5 mg/kg) or with methohexitone (2 mg/kg). Sensations at the site of the injection were more common when the drugs were injected into a vein in the dorsum of the hand (58% for propofol and 28% for methohexitone) when compared to a vein in the forearm or antecubital area (7 to 8% with sensations). After induction of anaesthesia intravenous suxamethonium was given, and endotracheal intubation carried out. Anaesthesia was subsequently maintained using nitrous oxide, oxygen and enflurane. One minute after intubation a similar decrease in mean systolic arterial pressure was noted in both groups but the increase in mean heart rate observed in the methohexitone group (22 beats/min) was significantly (P less than 0.01) greater than that seen in the propofol group (11 beats/min). Excitatory side effects were observed in only one patient in the propofol group and in 12 patients in the methohexitone group (P less than 0.01 between groups). Walking and perceptual speed tests of recovery showed transient impairment of psychomotor skills for 30 to 60 min after both anaesthetic regimens. The incidence of nausea or vomiting was similar (27 to 33%) in both groups. It is concluded that both propofol in emulsion form and methohexitone are satisfactory induction agents in outpatient dentistry. Propofol provided a smoother induction of anaesthesia and recovery was as rapid as after anaesthesia induced with methohexitone.

Adult↗

Droperidol prevents and treats nausea and vomiting after enflurane anaesthesia.

One hundred and twelve women undergoing elective orthopaedic surgery under enflurane anaesthesia were given, in a double-blind random fashion, 2.5 mg of droperidol i.m. before anaesthesia, or 1.25 mg of droperidol or a saline placebo i.v. at the end of anaesthesia in an attempt to prevent post-operative vomiting. The administration of droperidol 1.25 mg (for those receiving initially 1.25 mg of droperidol) or saline (for those receiving initially 2.5 mg of droperidol or saline) was repeated i.m. during the 24 post-operative hours in a blind manner if the patient complained of nausea, retched or vomited. Significantly fewer patients (P less than 0.05) given i.m. or i.v. droperidol had emetic symptoms than patients given saline. Furthermore, 51% of the patients given saline needed additional doses of saline, whereas only 27% of the patients given i.m. and 36% of the patients given i.v. droperidol required a second dose (P less than 0.05 between groups). More of the patients given saline (23%) than those given droperidol (8% to 9%), as a blind drug (P less than 0.05), needed to be given additional droperidol as a known anti-emetic because of the failure of the blind drug to prevent or treat symptoms. It is concluded that droperidol given either as a single dose of 2.5 mg i.m. or in repeated doses of 1.25 mg i.v. is effective in the prevention and treatment of post-operative nausea and vomiting after enflurane anaesthesia.

Adult↗

Effect of hydroxyethyl starch and dextran on plasma volume and blood hemostasis and coagulation.

Six healthy male subjects were given in a crossover fashion medium molecular weight (HES 125) and low molecular weight (HES 40) hydroxyethyl starch, dextran, and balanced salt solution by intravenous infusion. The plasma volumes were determined using labeled albumin and plasma protein measurements. Three properties of factor VIII protein complex and indices of blood coagulation and hemostasis were measured before and after the infusions. Both the salt solution and HES 40 increased plasma volume, but their effect wore off within 3 hours. Dextran and HES 125 increased plasma volume significantly (P less than 0.001) more than the salt solution did, and the expansion was maintained for 24 hours. Plasma volume increases (dextran and HES 125) were associated with high nonglucose carbohydrate levels in plasma and low levels in urine. No or slight increases in plasma volumes (HES 40), on the other hand, were associated with low and high carbohydrate levels in plasma and urine, respectively. Serum alpha-amylase activity increased significantly after both HES preparations as compared to salt solution. Dextran and HES 125 decreased all the three values of factor VIII, these decreases being maximal 3 to 6 hours after administration and highest (about 25 per cent) for F VIII R:Ag and F VIII R:cof. It is concluded that HES 125 and dextran are equally effective plasma expanders.

Adult↗

Ventilatory and mental effects of alfentanil and fentanyl.

Forty healthy, young volunteers received intravenously, in a double-blind and random fashion, 7.5 or 15 micrograms/kg of alfentanil, 1.5 or 3 micrograms/kg of fentanyl, or saline. The ventilatory response to CO2 was measured before and at 4, 20, 30, 50, 80, and 120 min post-treatment. Mental and psychomotor functions were measured before and at 10, 40, 100, 130, and 180 min post-treatment. Low and high-dose fentanyl caused significant respiratory depression up to 30 and 80 min post-treatment, respectively, while there was no depression with low-dose alfentanil and only at 4 min with high-dose alfentanil. The fentanyl to alfentanil potency ratio for respiratory depression was 13:1. High-dose fentanyl caused more intense and prolonged mental effects than other treatments. Neither drug affected learning or recall, although high-dose fentanyl impaired motor activity. Nausea and vomiting rates were similar between high-dose alfentanil and low-dose fentanyl.

Adult↗

Clinical effectiveness and untoward effects of new agents and techniques used in intravenous sedation.

An ideal i.v. sedative for dentistry should provide anti-anxiety and analgesic activity, amnesic action, and patient cooperation without depression of the cardiorespiratory system and with rapid recovery. Lorazepam does not provide any advantages over the currently available agents, but midazolam, a new water-soluble benzodiazepine, and later selective benzodiazepine receptor antagonists may play an important role in outpatient sedation.

Adult↗

Local anesthetic techniques for bronchoscopies.

Local anesthetic techniques are often preferable to general anesthesia for bronchoscopies since these examinations are mostly undertaken as outpatient procedures. To be successful bronchoscopy under local anesthesia must satisfy three criteria: the technique used must produce adequate anesthesia: the procedure must be safe: and the technique should be easy for the patient as well as for the physician. Local anesthesia of the respiratory tract for these procedures can be achieved by laryngotracheal spraying or ultrasonic nebulizer administration of lidocaine. For fiberoscopic procedures lidocaine can also be administered through the fiberoscope. When the local anesthetic techniques are supplemented with light sedation, the procedure is easier and more acceptable to the patients. Using small doses of diazepam, flunitrazepam, or midazolam i.v. one can produce amnesia for the procedure and still discharge the patients 2 h after the procedure with a responsible adult. In many cases local anesthesia supplemented by intravenous sedation is a proper alternative and should be preferred to general anesthesia in ambulatory practice for diagnostic bronchoscopies.

Anesthesia, Local↗

Full recovery after different anesthesia techniques for short diagnostic procedures.

When suitable, local anesthetic techniques are preferable for ambulatory short diagnostic procedures. If general anesthesia is used no or only very light premedication, induction with a short acting i.v. agent and the maintenance of anesthesia with nitrous oxide plus oxygen plus an inhalational agent or alternatively with short acting i.v. anesthetic and analgesic seems today to provide fastest recovery. Patients should always arrange for a responsible adult to accompany them home. Minimal requirements for safe discharge should in addition to stable vital signs and the ability to maintain oral fluids include that patients are able to dress themselves and able to walk out. These criteria, however, do not indicate that patients are fully recovered after anesthesia. In most cases patients are not fully recovered when discharged from hospital after even brief anesthesia and they should refrain from driving, operating machinery, and delay making important decisions for at least 24 hours after anesthesia.

Adjuvants, Anesthesia↗

Suitability of plasma expanders in patients receiving low-dose heparin for prevention of venous thrombosis after surgery.

Patients (132) receiving low-dose heparin for the prevention of venous thrombosis after surgery were given in random order in addition to standard fluid therapy, a 500 ml infusion of balanced salt solution and glucose, 4% gelatine, 6% dextran, or 6% hydroxyethyl starch (mean molecular weight 40,000 or 125,000) after induction of anaesthesia. Variables of blood coagulation and haemostasis were measured before and after the operation, and peroperative bleeding tendency and postoperative bleeding complications were subjectively evaluated by the surgeon. None of the treatments significantly decreased platelet count or increased capillary bleeding time when compared to values before operation. The peroperative bleeding tendency was similar after each infusion (moderately-to-markedly increased in 18-32% of the patients). None of the patients given balanced salt solution and glucose only had postoperative bleeding complications, whereas 8-18% of patients given plasma expanders presented with such complications (plasma expanders vs no plasma expanders P less than 0.05). The results suggest that administration of gelatine, dextran or hydroxyethyl starch should be avoided in patients receiving low-dose heparin treatment for surgery.

Anesthesia↗

Ventricular fluid pressure in neurosurgical patients receiving intravenous lorazepam for premedication.

The effect of 0.05 and 0.03 mg/kg of intravenously administered lorazepam on the ventricular fluid pressure (VFP) was recorded continuously for 45-90 minutes in 13 wakeful spontaneously breathing unanaesthetized patients with hydrocephalus. The initial VFP was low in 11 patients with low-pressure hydrocephalus, and at the upper level of normal in 2 who had stenosis of the aqueduct. Lorazepam caused minute changes in VFP. The largest transient increased (7 and 16 torr) occurred in the two patients with the highest initial VFP. Blood acid-base balance, blood pressure, and heart rate remained unaltered. However, lorazepam caused such drowsiness that it was difficult to check the patients' level of consciousness. For this reason, intravenously administered lorazepam in a dosage of 0.03 mg/kg or more seems unsuitable for premedication in neurosurgical patients with brain disease.

Adult↗

Unpredictable central nervous system effects after lorazepam premedication for neurosurgery.

Administration of lorazepam for preanaesthetic medication is generally expected to produce amnesic action. We conducted two studies to evaluate the relationship of plasma levels of lorazepam with its clinical effects. Forty patients, receiving 0.03 or 0.05 mg/kg lorazepam i.m. as preanaesthetic medication for various neurosurgical procedures, were asked 24 h after anaesthesia whether they could recall the insertion of the i.v. needle and a picture shown to them before induction of anaesthesia. Another 11 patients were given 0.03 mg/kg lorazepam i.v. and their degree of drowsiness was rated immediately before induction of anaesthesia. Plasma levels of lorazepam were measured by gas chromatography from samples drawn before induction of anaesthesia. No relationship between either the dose of lorazepam used or the plasma levels of lorazepam and the incidence of amnesia or the degree of drowsiness was observed. Three patients receiving 0.05 mg/kg of lorazepam i.m. had prolonged drowsiness, which made it difficult to check the patients' neurological condition after the operation. It is postulated that the unpredictable and variable central nervous system effects of lorazepam in neurosurgical patients may be due to differences in the capacity of lorazepam to penetrate the blood brain barrier.

Adult↗

Effect of supramaximal vagal stimulation in combination with hypoxia, respiratory acidosis and deep halothane anaesthesia on cardiovascular function in dogs.

Vagal reflexes are generally recognized as a possible cause of cardiac arrest during anaesthesia. Studies were performed to determine whether hypoxia, respiratory acidosis or deep halothane anaesthesia modify the cardiovascular effect of vagal stimulation (VS) in dogs. The animals were anaesthetized with intravenous urethane and chloralose, and paralysed with metocurine. Normal temperature and arterial blood gas variables were maintained and supramaximal VS was applied to the distal end of both vagus nerves for 5 min. No differences were found in any of the variables measured among the time periods when VS was repeated five times in six control dogs receiving urethane-chloralose basal narcosis only to determine the effects of time. VS resulted in 15 +/- 3 s (mean +/- s.e. mean) of asystole. Heart rate, cardiac output (CO) and mean arterial pressure (MAP) were still significantly decreased (P less than 0.001) and central venous pressure, right atrial pressure, pulmonary capillary wedge pressure (PCW), systemic (SVR) and pulmonary vascular resistance significantly increased (P less than 0.01--P less than 0.001) at the end of stimulation when compared to values before VS in all 24 dogs. Neither hypoxia [PaO2 5.3 kPa (40 mmHg)] nor respiratory acidosis [pH 7.00, PaCO2 10.6 kPa (80 mmHg)] modified these effects of VS. VS during halothane anaesthesia (1.6% end-tidal concentration) resulted in further significant decreases (P less than 0.05--P less than 0.001) in CO, MAP, mean pulmonary arterial pressure, PCW and SVR when compared to VS under basal narcosis. VS under halothane anaesthesia combined with hypoxia or respiratory acidosis did not decrease the cardiovascular parameters as much as VS under halothane anaesthesia alone. VS alone, or in combination with hypoxia or respiratory acidosis, failed to cause persistent asystole.

Acidosis↗

Diazepam effects and kinetics in Caucasians and Orientals.

Mental and psychomotor effects and diazepam kinetics were studied in Caucasian and Orientals. 12 Caucasian and 13 Oriental young adults received on one of two occasions, separated by 2 weeks, either 0.2-mg/kg diazepam or saline intravenously. Serum diazepam and desmethyldiazepam concentrations were measured by electron-capture gas-liquid chromatography in samples drawn up to 72 hr after injection. Serum protein binding was measured by equilibrium dialysis. Subjects were tested on a battery of psychological tests before and 0.5, 2, and 4 hr after treatment. While the free fraction of diazepam was identical in both races (0.02), volume of distribution at steady state (Vdss) was different when calculated as absolute volume (Vdss = 76.55 +/- 9.63 l in Caucasians and 54.96 +/- 4.55 l in Orientals, p = 0.04) and marginally significant when corrected for body weight (Vdssl/kg = 1.10 +/- 0.11 in Caucasian and 0.88 +/- 0.05 in Orientals, p = 0.07). total body clearance (Cl), but not elimination half-life (t 1/2), was higher in Caucasians than Orientals, p less than 0.01; t 1/2 = 37.70 +2- 5.53 hr in Caucasians and 41.77 +/- 3.80 in Orientals). Desmethyldiazepam levels were higher in Orientals than Caucasians. Mental and psychomotor effects were maximal at the first session (0.5 hr), followed by complete recovery by the 4-hr session. Effects were similar in both groups. If repeated dosing causes a higher rate of cumulated diazepam serum levels in Orientals, as expected, there might be deeper brain depression in that group.

Adult↗

Time course of mental and psychomotor effects of 30 per cent nitrous oxide during inhalation and recovery.

Two experiments were conducted testing the duration of action of nitrous oxide on human performance. In the first experiment, 11 subjects inhaled 30 per cent nitrous oxide for two periods of 40 min each, 45 min apart. Their mental and psychomotor skills were measured using free recall, tapping board, arithmetic and flicker fusion tests before and 2, 12, 22 and 32 min after establishing and end-tidal concentration of N2O of 30 per cent. Recovery was tested using the same tests 2, 12, 22 and 32 min after discontinuation of N2O. Eleven additional subjects inhaled oxygen only and served as a control group. In the second experiment, 8 subjects received both 30 per cent N2O and oxygen in cross-over fashion, and their flicker fusion threshold was measured. When compared to baseline or oxygen administration, N2O significantly impaired tapping rate, number of words recalled, and performance in arithmetic tests. The effects of N2O were maximal at 2 min and remained similar throughout the entire administration. In flicker fusion tests, the effects of N2O were similar to those of stimulant drugs; N2O improved the subjects' ability to discriminate the fusion of flickering light. Recovery was complete in 22 min. The effects of, and recovery from the second administration of N2O were similar to those of the first experiment. There was no evidence of development of tolerance to mental and psychomotor effects of the drug.

Adult↗

Evaluation of instrumented force platform as a test to measure residual effects of anesthetics.

Recovery from anesthesia was assessed in a controlled manner in 38 healthy student volunteers, using two psychomotor tests (perceptual speed and tapping board) and an instrumented force platform 1, 3, 5 and 7 h after intravenous injection of 0.3 mg/kg diazepam, 2.0 mg/kg methohexital, 6.0 mg/kg thiopental or saline. Postural stability remained unaltered but the performance on psychomotor tests improved when the tests were repeated after saline injection. Methohexital did not induce any changes in body sway or psychomotor performance at the time periods tested when compared with saline. Postural stability of subjects receiving thiopental or diazepam was imparied (P less than 0.001) for 1 and 7 hours after anesthesia, respectively, when compared with saline. The impairment on performance in the psychomotor tests induced by thiopental or diazepam was of smaller magnitude and for diazepam of shorter duration than balance disturbances measured with the body sway tests. Further clinical studies on the use of the instrumented force platform as a fast and easily interpretable guideline for discharge from hospital after different modes of outpatient anesthesia are warranted.

Adult↗

Single and repeated dose comparison of three antihistamines and phenylpropanolamine: psychomotor performance and subjective appraisals of sleep.

1 In a double-blind cross-over study, nine healthy male students received placebo, brompheniramine 12 mg), carbinoxamine (12 mg), clemastine (1 mg), and phenylpropanolamine (50 mg) orally. Three doses of each drug were given: at 08.30 h and 21.00 h on the first day of treatment and at 08.30 h on the following day. 2 Psychomotor skills and subjective feelings were recorded before and 2, 6 and 12 h after the first dose on day 1 as well as before and 2 and 6 h after the third dose on day 2. Subjective appraisals of sleep were requested on the morning of day 2. 3 All antihistamines tended to cause subjective drowsiness on the first day of treatment. Drowsiness was felt for a maximum of 2 h after carbinoxamine, 6 h after brompheniramine, and 12 h after clemastine. In contrast to antihistamines, phenylpropanolamine made subjects more alert and quick witted. Tolerance to the antihistamine-induced drowsiness developed on the second day. 4 Divided attention, tracking, speed anticipation and sleep were not affected by any drug. Carbinoxamine slowed reactions 2 h after the first dose, but no impairment was measured in objective tests after brompheniramine or clemastine. 5 Phenylpropanolamine improved reaction speed and reaction accuracy and enhanced flicker recognition throughout the study. Phenylpropanolamine plasma levels and improvement in flicker fusion test results correlated with each other on day 2. 6 The results suggest that phenylpropanolamine and the antihistamines studied are comparatively harmless to psychomotor performance and driving skills.

Adult↗

Comparison of laryngotracheal and ultrasonic nebulizer administration of lidocaine in local anaesthesia for bronchoscopy.

Inhalation of nebulized minute lidocaine droplets has been suggested to be a very safe and pleasant method to produce topical anaesthesia for bronchoscopy. We produced topical anaesthesia of the respiratory tract either by laryngotracheal spraying (LS) of lidocaine (439 +/- 85mg) or ultrasonic nebulizer administration (UNA) of lidocaine (462 +/- 81 mg) in 40 patients undergoing bronchoscopy. All patients also received an average of 15 mg of diazepam intravenously. Both modes of lidocaine administration produced adequate anaesthesia and were safe, but when rated on the visual analogue scale, both the efficacy of local anaesthesia and the cooperation of patients during bronchoscopy were better (P less than 0.05) after LS than those after UNA. The peak plasma concentrations of lidocaine (means +/- s.d.) were lower and occurred earlier after UNA (0.53 +/- 0.34 micrograms/ml at 5-15 min after administration) than those after LS (0.89 +/- 0.63 micrograms/ml at 15-25 min after spraying). The highest individual values measured (2.54 micrograms/ml after LS and 1.17 micrograms/ml after UNA) were much less than those reported toxic lidocaine plasma concentrations. It is concluded that bronchoscopy can be conducted under local anaesthesia as successfully and safely using inhalation of lidocaine droplets from an ultrasonic nebulizer as when using laryngotracheal spraying of lidocaine.

Aerosols↗