Propofol Total Intravenous Anesthesia Research Articles

Haemodynamic effects of the prone position: a comparison of propofol total intravenous and inhalation anaesthesia

The haemodynamic changes of the prone position were investigated in 40 ASA I-II patients undergoing lumbar spine surgery. Patients were randomly assigned, following propofol intravenous induction, to receive maintenance of anaesthesia using either isoflurane 1-1.2% in air or target controlled propofol 3 microg.ml(-1) infusion. Measurements of non-invasive blood pressure, heart rate and cardiac output were made in the supine position. The patient was then turned prone onto a Montreal pattern mattress and measurements repeated. Cardiac output measurements were made using a non-invasive cardiac output monitor. We found a significant reduction in cardiac index in both groups and a significantly greater change with propofol compared to isoflurane on turning supine to prone (CI change 0.4 vs 0.7 l.min(-1).m(-2) p = 0.001 and SVRI change 89 vs 177 dyne.s(-1).cm(-5), p = 0.041). We conclude that turning healthy patients prone produces a clinically significant reduction in cardiac output, the change being greater during maintenance of anaesthesia using propofol compared to isoflurane.

Combined propofol and remifentanil intravenous anesthesia for pediatric patients undergoing magnetic resonance imaging

A prospective observational case series of children receiving light general anesthesia for magnetic resonance imaging (MRI) was performed. Our purpose was to examine the merit of anesthesia and recovery/discharge times of combined remifentanil and propofol total intravenous anesthesia (TIVA) in spontaneously breathing children. After IRB approval and informed consent, 56 patients receiving Remi/Propofol TIVA (Remifentanil 10 microg.ml(-1) Propofol 10 mg.ml(-1)) were observed. Blood pressure, respiratory rate, endtidal CO(2) (P(E)CO(2)), oxygen saturation and temperature were recorded at the start and finish of anesthesia. In addition, induction and recovery times were noted. Recovery time was from scan completion until discharge from the initial recovery area. Discharge time was from scan completion to discharge home. Fifty-six patients received Remi/Propofol TIVA. The mean Remi/Propofol recovery and discharge times were 8.9 and 28.2 min, respectively. There was a statistically significant decrease in respiratory rate and increase in CO(2) from the start to the end of the procedure. During the scan, seven patients moved. One patient experienced postprocedure nausea and or vomiting. The combination of remifentanil and propofol for TIVA may be an effective method of light general anesthesia in pediatric patients undergoing MRI.

Effects of Sevoflurane, Isoflurane and Propofol Infusions on Post-Operative Recovery Criteria in Geriatric Patients

We compared the effects of sevoflurane, isoflurane and propofol infusions on postoperative recovery criteria in geriatric patients. Sixty patients aged > 65 years, classified as American Society of Anesthesiologists (ASA) group 1 or 2 and undergoing gynaecological or urological procedures were randomized equally into three groups. Group 1 received 1 minimum alveolar concentration (MAC) sevoflurane in a 50% O2/N2O mixture and group 2 received 1 MAC isoflurane in a 50% O2/N2O mixture. Group 3 received a 50% O2/N2O mixture plus propofol total intravenous anaesthesia (8 mg/kg for the first 30 min, followed by 6 mg/kg for maintenance). Recovery criteria comprising the times to spontaneous eye opening, extubation, response to verbal stimuli and orientation were recorded following the discontinuation of anaesthesia. Recovery times were significantly shorter in groups 1 and 3 compared with group 2. We conclude that sevoflurane and propofol had similar effects on recovery criteria and were associated with a faster recovery than isoflurane.

The Minimum Infusion Rate (MIR) of Propofol for Total Intravenous Anesthesia after Premedication with Xylazine in Horses

To investigate an adequate infusion rate of propofol for total intravenous anesthesia (TIVA) in horses, the minimum infusion rate (MIR) comparable to the minimum alveolar anesthetic concentration (MAC) of inhalation anesthetic was determined under constant ventilation condition by intermittent positive pressure ventilation (IPPV). In addition, arterial propofol concentration was measured to determine the concentration corresponding to the MIR (concentration preventing reaction to stimulus in 50% of population, Cp(50)). Further, 95% effective dose (ED(95)) was estimated as infusion rate for acquiring adequate anesthetic depth. Anesthetic depth was judged by the gross purposeful movement response to painful stimulus. MIR and Cp(50) were 0.10 +/- 0.02 mg/kg/min and 5.3 +/- 1.4 microg/ml, respectively. ED(95) was estimated as 0.14 mg/kg/min (1.4MIR).

Propofol and remifentanil total intravenous anesthesia for a patient with Huntington disease

Huntington disease presents many challenges for the anesthetist. Of primary importance is that these patients are at increased risk of pulmonary aspiration. The use of short-acting anesthetic drugs should, therefore, be advantageous in promoting the rapid return of protective airway reflexes. We report the first documented use, to date, of propofol and remifentanil total intravenous anesthesia in a patient with Huntington disease and demonstrate its efficacy and safety.

Propofol total intravenous anesthesia for MRI in children

The aim of this study was to assess clinical signs of airway patency, airway intervention requirements and adverse events in 100 children receiving propofol total intravenous anesthesia for magnetic resonance imaging, with spontaneous ventilation and oxygenation via nasal prongs. Airway patency was clinically assessed and stepwise interventions were performed until a satisfactory airway was achieved. Propofol requirements, vital signs, procedure times and adverse events were also recorded. Ninety-three per cent of children had no signs of airway obstruction when positioned with a shoulder roll only, two required a chin lift, four required an oral airway and one required lateral positioning. The mean propofol induction dose was 3.9 mg.kg(-1) (range 1.8-6.4 mg.kg(-1)). The mean propofol infusion rate was 193 microg.kg(-1).min(-1) (range 150-250 microg.kg(-1).min(-1)). The initial and final mean respiratory rates were 26 and 23 b.min(-1) (P < 0.05). Movement was more likely at lower infusion rates (mean 175 microg.kg(-1).min(-1)). There were no respiratory or cardiovascular complications (calculated risk: 95% CI = 0-3%). The mean time from end of scan to discharge home was 44 min. This study demonstrates good preservation of upper airway patency and rapid recovery using general anesthetic doses of propofol in children.

Anaesthetic management during labour of a manifesting carrier of Duchenne muscular dystrophy

We describe the peripartum anaesthetic management of a 36-year-old woman who was a manifesting carrier of Duchenne muscular dystrophy. Duchenne muscular dystrophy is an X-linked recessive disorder affecting young males associated with severe complications during anaesthesia if depolarising neuromuscular blocking drugs and volatile agents are used. A manifesting carrier is a heterozygous female who demonstrates the disease in a milder form than in males. This probably occurs because of skewed X-inactivation. We planned to establish regional anaesthesia should an operation be necessary during labour or delivery and to use propofol total intravenous anaesthesia and rocuronium if general anaesthesia became unavoidable. At 37 weeks, the woman went into spontaneous labour, but fetal distress necessitated caesarean section for which combined spinal-epidural anaesthesia was used.

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The role of human lungs in the biotransformation of propofol.

The metabolism of propofol is very rapid, and its transformation takes place mainly in the liver. There are reports indicating extrahepatic metabolism of the drug, and the alimentary canal, kidneys, and lungs are mentioned as the most probable places where the process occurs. The aim of this study was to determine whether the human lungs really take part in the process of propofol biotransformation. Blood samples were taken from 55 patients of American Society of Anesthesiologists grade 1-3 scheduled for elective intracranial procedures (n = 47) or for pulmonectomy (n = 8). All patients were premedicated with diazepam (10 mg) administered orally 2 h before anesthesia. Propofol total intravenous anesthesia was performed at the following infusion rates: 12 mg. kg-1. h-1, 9 mg. kg-1. h-1, and 6 mg. kg-1. h-1. Fentanyl and pancuronium bromide were also administered intermittently. After tracheal intubation, the lungs were ventilated to normocapnia with an oxygen-air mixture (fraction of inspired oxygen = 0.33). Blood samples for propofol and 2,6-diisopropyl-1, 4-quinol analysis were taken simultaneously from the right atrium and the radial artery, or the pulmonary artery and the radial artery. The concentration of both substances were measured with high-performance liquid chromatography and gas chromatography-mass spectroscopy. The concentration of propofol in the central venous system (right atrium or pulmonary artery) is greater than in the radial artery, whereas the opposite is observed for propofol's metabolite, 2,6-diisopropyl-1,4-quinol. Higher propofol concentrations are found in blood taken from the pulmonary artery than in the blood collected from the radial artery. Human lungs take part in the elimination of propofol by transforming the drug into 2,6-diisopropyl-1,4-quinol.

Anaesthetic Management of a Patient with Low Tracheal Obstruction Requiring Placement of a T-Y Stent

A 60-year-old man with a history of oesophagectomy for carcinoma presented with worsening dysphagia, dyspnoea and tachypnoea secondary to oesophageal stricture and tumour invasion of the trachea causing a "ball-valve" obstruction. The patient required placement of a T-Y tracheobronchial stent to relieve the airway obstruction and was successfully managed using sevoflurane for gaseous induction followed by maintenance with propofol total intravenous anaesthesia.

A Comparison of Midazolam and Propofol on Hemodynamic Changes and Postanesthetic Recovery as Hypnotics for Total Intravenous Anesthesia(TIVA)

Total intravenous anesthesia(TIVA) is a anesthetic technique where hypnosis, analgesia and muscle relaxation are provided solely by intravenously administered drug without the use of anesthetic vapors or gases including nitrous oxide. For TIVA, midazolam and propofol have been used as hypnotics because of their relatively short elimination half life. Hemodynamic function during induction of anesthesia, the fentanyl and naloxone requirements, and speed of recovery from TIVA with midazolam/fentanyl(group M, n=20) or prapofol/fentanyl (group P, n=20) were compaired in patients undergoing surgery. Forty patients were randomly assigned to receive either 0.2 mg/kg midazolam in 5 min followed by 0.4 mg/kg/hr for 20 min, 0.3 mg/kg/hr for next 20 min, 0.05~0.2 mg/kg/hr until 10~15 min before skin closure, or 2 mg/kg propofol in 5 min followed by 9 mg/kg/hr for 30 min and 4.5 mg/kg/hr until 10~15 min before skin closure. Simultaneously, a variable rate infusion of fentanyl was given. Patients were intubated with an aid of vecuronium and ventilated with 40% oxygen in air. In both groups, mean arterial pressure decreased significantly(P 0.05). The total dose, duration and rate of infusion of fentanyl was similar in both groups. 16 patients in group M and 9 patients in gmup P needed naloxone for recovery of respiration and 10 patients in group M needed flumazenil for recovery of consciousness. Recovery as judged by scoring system(sedation score, comprehension score, orientation score) was shorter in group P than group M. Among side effects, resedation was more frequent in group M(9 pts) than P group(0 pt). In conclusion, both midazolam and propofol were useful hypnotics for TIVA. But, group M showed more stable hemodynamics than group P during induction period and P group showed earlier recovery than group M. We concluded that the selection of hypnotics between midazolam and propofol for TIVA depends on situation such as better hemodynamics during induction period or earlier recovery.(Korean J Anesthesiol 1995; 29: 671~679)

Total intravenous anaesthesia with propofol, alfentanil, and oxygen-air: three different dosage schemes

Three different dosage schemes of propofol infusions combined with a fixed-rate alfentanil infusion were investigated in total intravenous anaesthesia. In 30 premedicated patients, divided at random into three groups, anaesthesia was induced with propofol 2 mg.kg-1 immediately followed by an alfentanil infusion 10 micrograms.kg-1.min-1 as a loading dose which was decreased after ten minutes to a maintenance dose of 1 microgram.kg-1.min-1. Vecuronium bromide 0.1 mg.kg-1 was used as the muscle relaxant. After induction of anaesthesia a propofol infusion 2 mg.kg-1.hr-1 was started in group A, 3 mg.kg-1.hr-1 in group B and 4 mg.kg-1 hr-1 in group C. At signs of light anaesthesia supplementary bolus doses of 20 mg propofol and 1 mg alfentanil were given. The patients' lungs were ventilated with air-oxygen (FIO2 0.35). The mean systolic and diastolic blood pressures showed no statistical significant differences between the three groups. A significant (P less than 0.01) decrease of the mean systolic and diastolic blood pressures was present after induction of anaesthesia and tracheal intubation. Recovery was uneventful in all but one patient, who had ventilatory depression that responded to naloxone (0.2 mg IV). Awareness did not occur in any patient. The only difference between the three groups was the higher number of supplementary bolus doses of propofol and alfentanil needed in group A (P less than 0.01). In total intravenous anaesthesia propofol 3 and 4 mg.kg-1.hr-1 as a maintenance dose combined with a two-step fixed-rate alfentanil infusion provided smooth anaesthesia and uneventful rapid recovery.