Intravenous Infusion Of Propofol Research Articles

New airway device for ventilation and monitoring in pediatric patients undergoing MRI study

A method of administering continuous positive airway pressure via a new airway device to prevent upper airway obstruction and preserve spontaneous respiration under total intravenous anesthesia has been adapted for children undergoing deep sedation for MRI studies. Presented herein is a retrospective study of 45 pediatric patients, ages 5 months to 7 years, who underwent an MRI study under general anesthesia using a modified nasal vestibule airway (NVA®), a pressure-sealing nasal cannula that can be used in conjunction with an anesthesia circuit to deliver nasal-CPAP during anesthesia. After inhalation induction of anesthesia with sevoflurane, an intravenous infusion of propofol was used to maintain anesthesia. A NVA®, downsized to fit the nasal vestibule of the child, was inserted, taped in place, and connected to a Mapleson F circuit. An extra long extension of corrugated tubing, a SNOR-SCOPE® circuit stethoscope, and the fluctuations of a reservoir bag allowed monitoring and assisted respirations from the foot of the MRI table. Other monitors included CO2 sampled at the mouth and the fluctuations of a PORTEX® disposable pressure gauge. The records of 45 pediatric patients were reviewed. No significant anesthesia complications were found. A new approach is offered to maintain airway patency, monitoring and spontaneous respirations in pediatric patients undergoing MRI study. This pressure-sealing nasal cannula can deliver CPAP under anesthesia while avoiding the requirement of an invasive airway and facilitating additional monitoring and control not possible with an ordinary nasal cannula. This NVA may be used in other locations in pediatric patients where endotracheal intubation is not necessary or impossible.

Preserved consciousness in general anesthesia during carotid endarterectomy: a six-year experience

We prospectively evaluated safety and efficacy from our six-year results of general anesthesia (GA) using remifentanil conscious sedation in carotid endarterectomy (CEA). From January 2005 to December 2010, 625 consecutive CEAs were performed on 545 patients (male/female 336/209, age 75 ± 7 years). After a superficial plexus block with ropavacaine, GA was induced with an intravenous infusion of propofol, using local lidocaine during tracheal intubation and a high-dose of remifentanil, in all cases reducing and then stopping the remifentanil infusion at the clamping time so that the patient would be awake and collaborating within a few minutes, as in local anesthesia. Data on postoperative morbidity and mortality, neurological complications, shunt insertions and the responses to one-day and three-month questionnaires on satisfaction were collected for all patients. The 30-day mortality was 0.32% (two patients). Only one major stroke (0.16%) and two minor strokes (0.32%) occurred. A shunt was deployed in 83 cases (13.3%). Eight patients (1.28%) reported cranial nerve injuries, and surgical drainage for postoperative hematoma was performed in 11 patients (1.8%). Thirty-one patients (4.6%) suffered postoperative nausea/vomiting. Almost all patients were satisfied at the 24-h (94.6%) and three-month (>98%) follow-up questionnaire. The six-year results for GA using remifentanil conscious sedation were very satisfactory and highlighted the advantages of both GA (hemodynamic stability and excellent control of ventilation) and local anesthesia (ease of evaluation of neurological status) in a calm and relaxed environment for both patient and surgeon.

Cranial epidural spread of contrast medium and new methylene blue dye in sternally recumbent anaesthetized dogs

ObjectiveTo examine the spread of solution in the epidural space of sternally recumbent dogs. Study designProspective experimental trial. AnimalsTen healthy adult Beagle dogs weighing 7.6 ± 1.1 kg. MethodsDogs were anaesthetized with total intravenous propofol infusion, and placed in sternal recumbency. A volume of 0.2 mL kg−1 contrast medium (CM) containing 1% new methylene blue (MB) dye was administered into the lumbosacral epidural space. Left to right lateral radiographs using a horizontal beam were taken every 5 minutes for 45 minutes. The perpendicular height (PH) between floor of the epidural canal of the highest vertebra and that of lumbosacral spinal canal was measured on radiographs. The angle of slope from the injection point toward the highest vertebral floor was measured. Immediately after taking the last radiographic image, dogs were euthanized and a laminectomy was performed from the cervical to lumbar vertebrae for visual evaluation of MB spread. The spread of CM and of MB as counted in number of stained vertebra were compared, and each of these data sets were further compared to PH and angle, using linear regression analyses. ResultsThe PH and angle were (mean ± SD) 3.8 ± 0.8 cm and 14.8 ± 2.8° respectively. The most cranial spread of CM was at 12.7 ± 5.7 (range: C6–L3) vertebrae, and at 14.0 ± 5.4 (range: C6–L2) vertebrae for MB staining. There were no significant correlations between PH and spread of CM (R2 = 0.08) or MB (R2 = 0.13), between angle and spread of CM (R2 = 0.05) or MB (R2 = 0.02), respectively. CM and MB demonstrated proportional relationship (R2 = 0.82, p < 0.001). ConclusionsNo significant inhibitory effect of upward slope on cranial epidural spread of the solution was observed. Other factors may have greater effect on epidural spread in sternally recumbent dogs.

The use of sugammadex in a patient with myotonic dystrophy

Editor, Patients with myotonic dystrophy show myotonic responses to succinylcholine1 and neostigmine,2 and increased sensitivity to non-depolarising muscle relaxants.3 Sugammadex. a novel drug developed specifically for the rapid reversal of neuromuscular blockade induced by steroidal non-depolarising muscle relaxants, would be useful in patients with muscular disorders. Although the use of sugammadex was reported in a patient with myasthenia gravis,4 it has not been addressed in other disorders. A 24-year-old woman, 160 cm in height and weighing 75 kg, was scheduled for laparoscopic ovarian cystectomy. Her father and brother were previously diagnosed with myotonic dystrophy. At the age of 22, she was diagnosed by a neurologist as having myotonic dystrophy. Physical examination showed the typical facies and frontal baldness of myotonic dystrophy. Her sternocleidomastoid muscles were atrophic, and muscle strength in her hands, forearms and lower limbs was weak. Serum creatine phosphokinase was as high as 624 IU l−1 (normal range for women, 47–176 IU l−1). ECG and echocardiography were normal. She had myotonia in the hands and pain in the proximal upper limb muscles. She had a history of rhabdomyolysis after acetaminophen. Her physical status was classified as ASA 2. Anaesthesia was induced with intravenous propofol (2 mg kg−1) and remifentanil (0.5 μg kg−1 min−1) and maintained with intravenous infusions of propofol (4 mg kg−1 h−1) and remifentanil (0.2 μg kg−1 min−1). Ultrasound-guided bilateral transversus abdominis plane block was performed with 20 ml of 0.375% ropivacaine on each side. After induction of anaesthesia, but before administration of rocuronium for muscle relaxation, monitoring of neuromuscular activity was started using acceleromyography (TOF-Watch SX, Schering-Plough Ireland, Dublin, Ireland) at the adductor pollicis muscle. Repetitive train-of-four (TOF) stimulation was applied at the ulnar nerve at the wrist every 15 s until the end of anaesthesia, or at least until recovery of the TOF ratio to 0.9. To obtain complete muscular blockade, 0.3 mg kg−1 of rocuronium was required which was less than the normal dose of rocuronium for induction (0.6 mg kg−1). Tracheal intubation was performed and maintenance doses of rocuronium (0.1 mg kg−1) were administered as needed at the reappearance of the fourth twitch (T4) of the TOF. After surgery, with reappearance of T2 after the last dose of rocuronium, sugammadex (2 mg kg−1) was administered. The time to recovery of the TOF ratio to 0.9 from the start of sugammadex administration was within 2 min. Propofol and remifentanil were maintained until recovery of the TOF ratio to 0.9, and stopped before tracheal extubation. Complete recovery of neuromuscular function was assessed by the performance of a successful 5-s head lift, following which tracheal extubation was performed. No exacerbation of myotonia and no recurrence of muscle relaxation were observed peri-operatively. Myotonic dystrophy is an autosomal dominant, multi-system disorder, characterised by skeletal muscle weakness, myotonia, cardiac conduction abnormalities and precocious cataracts. Myotonic patients may have abnormal responses to specific pharmacological agents used in anaesthesia.5 Patients with myotonic dystrophy have increased sensitivity to non-depolarising muscle relaxants.3 Further, anti-cholinesterase drugs can precipitate myotonia or may result in inadequate antagonism of neuromuscular blockade.3 Hence, small doses of non-depolarising muscle relaxants should be administered to patients with myotonic dystrophy. The combination of rocuronium and sugammadex, however, can replace these previous anaesthetic management regimes in patients with muscle disorders.4 In the present study, our patient with myotonic dystrophy required 0.3 mg kg−1 of rocuronium for induction, and showed normal recovery of the TOF ratio to 0.9 after the administration of sugammadex (2 mg kg−1). Therefore, she had increased sensitivity to rocuronium, and showed normal responses to sugammadex.6,7 We suggest that sugammadex might be useful in patients with myotonic dystrophy.

Propofol anaesthesia alters the cerebral proteome differently from sevoflurane anaesthesia

Previous studies suggest that propofol and sevoflurane anaesthesia in rats may have variable effects on the proteome. Brains from untreated rats and rats anaesthetised with intravenous propofol infusion or inhaled sevoflurane were collected at various time points post-anaesthesia and subjected to global protein expression profiling using two-dimensional gel electrophoresis. Significant changes in protein spot intensity (i.e. expression) between the propofol and sevoflurane groups demonstrated clear similarities and differences in proteomic regulation by these anaesthetics. The proteins regulated were broadly classified into groups involved in cytoskeletal/neuronal growth, cellular metabolism, signalling, and cell stress/death responses. Proteins concerned with cell death and stress responses were down-regulated by both agents, but the anaesthetics had variable effects on proteins in the other groups. Importantly, proteins such as Ulip2 and dihydropyrimidinase-like-2 were regulated in opposite directions by propofol and sevoflurane. Moreover, the time-course of regulation of proteins varied depending on the agent used. These data suggest different underlying mechanisms of proteomic regulation. We found that sevoflurane anaesthesia had more pronounced effects, on a wider range of proteins, and over an apparently longer duration than propofol. Thus, sevoflurane could be considered a more disruptive anaesthetic agent. Our findings show that protein expression is regulated differentially according to the anaesthetic agent and the method of delivery support and extend our previous observations of differential genomic regulation by anaesthetics in the brain. This study highlights the power of proteomic studies in assessing the effects of certain anaesthetics on the integrity of neuronal structure and function.

Effects of orexin-A on propofol anesthesia in rats

An active sleep homeostatic process is present during propofol anesthesia. Activation of the orexin system induces wakefulness, and inhibition of the orexin system causes narcolepsy. We hypothesized that orexin would affect propofol anesthesia. The effects of an intracerebroventricular (i.c.v.) injection of orexin-A (OXA) or an orexin-1 (OX-1) receptor antagonist, SB-334867, on the times to the loss and return of the righting reflex induced by propofol were examined in Wistar rats. The effects of propofol or OXA on norepinephrine (NE) and dopamine (DA) release from the prefrontal cortex (PFC) were examined using in vivo microdialysis. An i.c.v. injection of OXA (1nmol) decreased the time to emergence from propofol anesthesia mediated by the OX-1 receptor without changing anesthetic induction (n=8). An i.c.v. injection of SB-334867 (5 and 50nmol) increased the time to emergence from propofol anesthesia without changing anesthetic induction (n=8). Intravenous infusion of propofol decreased NE (48±8%; n=8) and DA (61.2±11%; n=8) release from PFC mediated by the GABA(A) receptor. An i.c.v. injection of OXA reversed the decreases in NE and DA release induced by propofol mediated by the OX-1 receptor (n=8). These results indicate that the orexin system may accelerate the emergence from propofol anesthesia associated with increases in the central noradrenergic and dopaminergic activity.

Right thoracic paravertebral anaesthesia for percutaneous radiofrequency ablation of liver tumours

Percutaneous radiofrequency ablation (PRFA) of liver tumours performed under local anaesthesia and intravenous sedation can cause severe pain to patients. This prospective study evaluated the efficacy of a right thoracic paravertebral block (TPVB) for anaesthesia and analgesia during PRFA of liver tumours. 20 patients, aged 44-74 years, with liver malignancies received a multiple injection TPVB at the T6-10 levels 30 min before the PRFA. An intravenous infusion of propofol (3-5 mg kg(-1) h(-1)) was administered to patients who requested to be sedated and intravenous fentanyl (25 µg bolus) was administered as rescue analgesia. Pain during the TPVB and PRFA was assessed using a numerical rating scale (NRS; 0, no pain; 10, worst imaginable pain). Patients were also assessed for residual pain and analgesic consumption during the 24 h after the intervention. The TPVB was well tolerated and produced ipsilateral sensory anaesthesia with satisfactory spread (median (range); 8 (6-11) dermatomes). The PRFA procedure caused mild pain (mean (standard deviation, SD); NRS 1.4 (1.9)) during the insertion of the ablation needle and the peak pain intensity during the therapeutic burn was moderate (mean (SD); NRS 5.0 (3.3)) in severity. During the 24 h after the PRFA, patients reported minimal pain and consumed very few analgesics. The mean (SD) satisfaction score (0, totally dissatisfied; 10, very satisfied) of the patients was 8.9 (1.1) and that of the radiologists was 8.8 (1.4). A right TPVB is safe and effective for anaesthesia and analgesia during PRFA of malignant liver tumours.

Ultrasound-Guided Axillary Plexus Block in a Child with Dystrophic Epidermolysis Bullosa

We report the use of ultrasound-guided axillary brachial plexus block in a child with dystrophic epidermolysis bullosa needing surgical treatment of the right hand. The regional anaesthesia was used in association with sedation/ anaesthesia. This technique is suitable for these difficult patients because it can minimise the risk of new bullae formation due to palpation of landmarks or unintentional intra- or subcutaneous injections. Initial anaesthesia/sedation was provided with sevoflurane until intravenous access was obtained, following which intravenous propofol infusion with ketamine boluses without any invasive airway management was continued for performance of the block and the procedure. This management plan provided good surgical conditions, early postoperative analgesia, minimised stress for the patient and avoided the need to manipulate the airway with instruments and the associated risk of mucosal bullae. The classification and breadth of clinical manifestation of epidermolysis bullosa is complex and briefly summarised. The anaesthetist should clarify the details of a particular patient's form of epidermolysis bullosa, especially in terms of mucosal involvement, as this may greatly influence planning for a procedure.

The Influence of Duration of Fluid Abstinence on Hypotension During Propofol Induction

Prolonged preoperative fasting might be expected to exacerbate hypotension during the induction of general anesthesia. We aimed to establish whether the duration of preoperative abstinence from fluids independently contributed to arterial blood pressure changes and dosage requirements during propofol induction. We prospectively recruited 130 ASA I or II nonhypertensive patients, ages 18 to 65 years scheduled for surgery under general anesthesia. Standard physiological and electroencephalographic bispectral index (BIS) monitoring was applied to each patient. Intravenous propofol infusion was commenced at 40 mg · kg(-1) · h(-1) and reduced to 8 mg · kg(-1) · h(-1) when the BIS decreased to 50. Frequent cardiovascular data were collected for 15 minutes. The primary endpoint was maximal percentage decrease from baseline mean arterial blood pressure (max%ΔMAP). The secondary endpoint was the propofol dose at which BIS decreased to 50 (PDBIS50). Univariate linear regression and then multivariate linear regression was used to analyze the associations between potential predictors, including fasting time, and these 2 endpoints. Mean fluid abstinence time was 694 minutes (range: 115 to 1263 minutes). Unstandardized regression coefficients (95% confidence intervals [CIs]) for fluid abstinence (minutes) versus max%ΔMAP (%) and PDBIS50 (mg) were, respectively, 0.003% (-0.002% to + 0.009%) and 0.021 mg (-0.017 mg to + 0.059 mg). On adjusting for other, significant predictors in a multivariate model and applying type II sum of squares tests, the corresponding values were -0.0001% (-0.004% to + 0.004%, P = 0.94) and -0.006 mg (-0.039 mg to + 0.026 mg, P = 0.70). The effect of a 1-hour increase in fluid abstinence on max%ΔMAP was therefore -0.01% (-0.26% to + 0.24%) and on PDBIS50, -0.38 mg (-2.34 mg to + 1.58 mg). When propofol is infused rapidly for induction of anesthesia in healthy adults younger than 65 years, the duration of preoperative fluid abstinence does not appear to affect MAP or propofol dose requirements.

The threshold of stroke volume variation in deteriuining volume expansion responsiveness during fluid therapy in patients ventilated with different tidal volumes

Objective To determine the threshold of stroke volume variation （SVV） in determining the volume expansion responsiveness during fluid therapy in patients ventilated with different tidal volumes. Methods Fifty ASA I or II patients aged 20-75 yr undergoing elective gastrointestinal surgery under general anesthesia were randomly divided into 2 tidal volume groups （ n = 25 each） ： group I VT 8 ml/kg （ group Vl ） and group II VT 10 ml/kg （group V2 ）. Radial artery was eannulated and connected to Vigelo monitor for continuous monitoring of cardiac index （CI）, stroke volume index （SVI）, systemic vascular resistance index （SVRI） and SVV. Internal jugular vein was cannulated for CVP monitoring. Anesthesia was induced with midazolam, propofol, fentanyl and rocuronium and maintained with intravenous propofol and remifentanil infusion. BIS was maintained at 40-50 during anesthesia. The patients were intubated and mechanically ventilated （VT 8/10 ml/kg, RR 8-12 bpm, oxygen flow 2 L/min）. 6% HES 130/0.4 7 ml/kg was infused iv at a rate of 0.4 ml·kg-1·min-1 after induction of anesthesia. MAP, HR, CVP, CI, SVV, SVI and SVRI were recorded before and at 3 min after fluid therapy. The changing rate of SVV （△SVV） and CI （△CI） were calculated. The criterion for effective volume expansion was ACI 15%. The ROC curve for SVV in determring the volume expansion responsiveness was plotted and the diagnostic threshold was determined. Results ROC curve showed that the diagnostic threshold of SVV was 10.5 % in group V1 and 13.5 % in group V2 . The sensitivity and specificity in determining effective volume expansion were 93.3 % and 75.0 % in group V1 and 87.5 % and 85.7 % in group V2 respectively. The area under the curve for SVV and 95% confidence interval （CI） were 0.946 （0.860-1.031） in group V1 and 0.951 （0.868-1.034） in group V2 . △SVV was negatively correlated with △CI in group V1 （ = 0. 553） and V2 （ = 0. 602）. Conclusion The threshold of SVV in determining the volume expansion responsiveness during fluid therapy is 10.5 % and 13.5 % in mechanically ventilated patients with tidal volmne of 8 and 10 ml/kg respectively. Key words: Stroke volume ; Respiration, artificial; Vascular capacitance

The supraglottic airway I-gel in comparison with ProSeal laryngeal mask airway and classic laryngeal mask airway in anaesthetized patients

The I-gel is a new single-use supraglottic airway device without an inflatable cuff. This study was designed to investigate the usefulness of the I-gel compared with the classic laryngeal mask airway (cLMA) and ProSeal laryngeal mask airway (pLMA) in anaesthetized, paralysed patients. The American Society of Anesthesiologists physical status I-II patients (n = 167) scheduled for orthopaedic surgery were included in this prospective study. General anaesthesia was achieved with intravenous infusion of propofol, remifentanil and rocuronium. The patients were randomly assigned to I-gel, pLMA and cLMA groups (64, 53 and 50 patients, respectively). Properly sized I-gel (No. 3-4) or LMA (No. 4-5) was inserted. We assessed haemodynamic data, airway leak pressure, leak volume, success rates and postoperative complications. There were no differences in the demographic data and haemodynamic data immediately after insertion of devices among the three groups. The airway leak pressures of the I-gel group (27.1 +/- 6.4 cmH2O) and pLMA group (29.8 +/- 5.7 cmH2O) were significantly higher than that of the cLMA group (24.7 +/- 6.2 cmH2O). The success rates for first attempt of insertion were similar among the three groups (P = 0.670). There were no differences in the incidence of adverse events except for the larger incidence of sore throat in the cLMA group. I-gel may have a similar airway sealing to that of pLMA, higher than that of cLMA, and is not associated with adverse events. The I-gel might be an effective alternative as a supraglottic airway device.

A Comparison of Parametric and Non-Parametric Approaches to Target-Controlled Infusion of Propofol

Nineteen adult patients of either gender received intravenous infusions of propofol, scaled to estimated lean body mass (LBM), for 150 minutes as part of a balanced anaesthetic. Arterial blood was assayed for whole blood propofol. The first subject received propofol at a fixed rate of 0.058 mg x min(-1) x kg(LBM)(-1). Subsequent groups received variable rate infusions based on the ratio of the infusion rate to the propofol concentration at each sampling point in the previous group, multiplied by the target concentration. After groups of one, two, five and 11 subjects, the median weighted residual was 0.040 and median absolute weighted residual was 0.153. Population pharmacokinetic analysis of the final group of six females and five males, aged 29 to 70 years and of 16.5 to 44.2% body fat, resulted in a two compartment pharmacokinetic model with coefficients and standard errors of V = 0.102 (0.0155) l/kg(LBM), V2 = 0.257 (0.079) l/kg(LBM), k10 = 0.423 (0.069)/min, k12 = 0.222 (0.051)/min, k21 = 0.084 (0.02)/min and clearance = 0.0418 (0.0023) L x min(-1) x kg(LBM)(-1). The only significant covariate was LBM. Within infusion data improved prediction when compared with data derived in previous studies from random observations.

Interrater Reliability of Drug-Induced Sleep Endoscopy

To determine the interrater reliability of drug-induced sleep endoscopy (DISE). Prospective cohort; blinded comparison. Academic referral center. Subjects with obstructive sleep apnea unable to tolerate positive airway pressure therapy. Drug-induced sleep endoscopy was performed with intravenous propofol infusion to achieve sedation, and the videoendoscopy recording was evaluated by 2 independent reviewers. The following outcomes were measured: a global assessment of obstruction at the palate and/or hypopharynx; the degree of obstruction at the palate and hypopharynx; and the contribution of individual structures (palate, tonsils, tongue, epiglottis, and lateral pharyngeal walls) to obstruction. A total of 108 subjects underwent DISE examination. Diagnostic sleep studies demonstrated a mean (SD) apnea-hypopnea index of 39.6 (24.0). Three-quarters of the subjects demonstrated multilevel airway obstruction at the palate and hypopharynx, with a diversity of individual structures contributing to obstruction. The interrater reliability for the presence of obstruction at the palate and hypopharynx (kappa values, 0.76 and 0.79, respectively) was higher than for the degree of obstruction (weighted kappa values, 0.60 and 0.44). The interrater reliability for the assessment of primary structures contributing to obstruction at the palate and hypopharynx (0.70 and 0.86) was higher than for the contributions of individual structures (kappa values, 0.42-0.71). The interrater reliability for evaluation of the hypopharyngeal structures was higher than for those of the palate region. The interrater reliability of DISE is moderate to substantial. Trial Registration clinicaltrials.gov Identifier: NCT00695214.

Efeitos da infusão contínua de propofol ou etomidato sobre variáveis intracranianas em cães

Avaliaram-se os efeitos da infusão contínua de propofol ou de etomidato sobre as variáveis intracranianas em cães nomocapneicos. Foram utilizados 20 cães adultos distribuídos aleatoriamente em dois grupos: grupo propofol (GP) e grupo etomidato (GE). Para o GP, os animais foram induzidos à anestesia com propofol (10mg/kg) e, ato contínuo, iniciaram-se a infusão do fármaco (0,6mg/kg/min) e a ventilação controlada. No GE, o etomidato foi usado para indução (5mg/kg) e manutenção empregando-se a dose de 0,5mg/kg/min nos 10 minutos iniciais e, em seguida, de 0,2mg/kg/min. Após 30 minutos da implantação do cateter de fibra óptica do monitor de pressão intracraniana (PIC) na superfície do córtex cerebral direito, realizaram-se as primeiras mensurações (M1) da PIC, da pressão de perfusão cerebral (PPC), da temperatura intracraniana (TIC), de temperatura corpórea (TC), da pressão arterial média (PAM) e da frequência cardíaca (FC). As demais mensurações ocorreram em intervalos de 20 minutos (M2, M3 e M4). O propofol e o etomidato não ocasionaram alterações significativas nas variáveis estudadas com exceção da TC e TIC. Concluiu-se que a infusão contínua desses fármacos em cães mantém a perfusão cerebral e a autorregulação cerebral. Cães anestesiados com etomidato apresentam efeitos adversos intensos e redução gradativa da temperatura corpórea e intracraniana.

Unilateral paravertebral block: an alternative to conventional spinal anaesthesia for inguinal hernia repair

Inguinal herniorrhaphy can be successfully performed using general, regional or local anaesthesia. Paravertebral block (PVB) has been used for unilateral procedures such as thoracotomy, breast surgery, chest wall trauma, hernia repair or renal surgery. We compared unilateral lumbar PVB with conventional spinal anaesthesia (SA) in 60 consenting ASA I and II males aged 18-65 years, scheduled for unilateral inguinal hernia repair. Patients were randomly assigned into two groups, P (n=30) or S (n=30) to receive either PVB or SA, respectively. Two patients (7%) in group P had to be converted to general anaesthesia due to block failure. During surgery, patients of both groups received intravenous infusion of propofol titrated to light sedation. The time to first post-operative analgesic requirement (primary outcome measure) as 342 +/- 73 min in group P and 222 +/- 22 min in group S (P<0.0001). Time to ambulation was 234 +/- 111 min in group P and 361 +/- 32 min in group S (P<0.0001). Urinary retention requiring catheterization were found in zero (0%) patients in group P compared with five (16%) in group S (P=0.024). It can be concluded that unilateral PVB is more efficacious than conventional SA in terms of prolonging post-operative analgesia and reducing morbidities in patients undergoing elective unilateral inguinal hernia repair.

Sedation for ERCP - Comparison Between Ketamine Diazepam Combination with Propofol Fntanyl Combination

For Endoscopic Retrograde Cholangio-pancreatography, an anaesthesiologist usually administers sedation to patient and search for more suitable regimen continues. This prospective randomized study was carried out to compare the efficacy, safety, tolerability and cost effectiveness of ketamine, diazepam combination to propofol, fentanyl combination for sedation during ERCP. One hundred and fifty patients of both sex, age between 18 to 70 years, ASA physical status I and II scheduled to undergo ERCP were included in this study. Patients were randomly allocated into two groups. Group A (n=75) sedated with ketamine 1.5mg/Kg body weight and diazepam 5-10 mg intravenously. Group B (n=75) sedated with propofol 1mg/Kg body weight and fentanyl 1μg/Kg body weight intravenously and intravenous infusion of propofol maintained at 50μg/Kg body weight/min throughout procedure. Both groups showed satisfactory sedating condition for ERCP. Incidences of hypertension and tachycardia were more in group A than group B and differences between two groups were statistically significant (P&lt; 0.01). Agitation and nightmares were found in 10 (13.33%) patients in group A. Mean recovery time was more in group A than group B and difference between two groups was statistically highly significant (P&lt;0.001). Sedation regimen of group B found 7 times more costly than group A. Both regimens found safe, effective, and tolerable for ERCP. However, recovery time is more with ketamine, diazepam but it found more cost effective than propofol fentanyl that is a concern in developing country like Bangladesh. Key Words: Endoscopic Retrograde Cholangiopancreatography (ERCP), Sedation, Ketamine, Diazepam, Propofol, Fentanyl, Intravenous. Journal of BSA, Vol. 20, No. 2, July 2007 p.45-50

Total Intravenous Anesthesia with Target-Controlled Infusion of Remifetanil and Propofol for Ablation of Atrial Fibrillation

Although ablation of atrial fibrillation (AF) is common in other centers, among us it is a new procedure. The choice of anesthesia, monitors, and anesthesiologic care for this procedure performed outside the surgical center has not been described. The objective of this report was to describe an anesthesia technique for ablation of AF. This is a 49-year old female weighing 73 kg, 155 cm, and ASA II due to hypertension. The patient was monitored with a 12-lead ECG, pulse oximetry, heart rate, bispectral electroencephalography for BIS measurement, suppression rate (SR), and SEF95, and mean arterial pressure (MAP). Intravenous target-controlled infusion (TCI) of propofol with a target of 4 microg x mL(-1), intravenous TCI of remifentanil with a target of 3 ng x mL(-1), and intravenous bolus of rocuronium 0.2 mg x kg(-1) were used for induction of anesthesia. The pharmacokinetic model of propofol described by Marsh was used and incorporated into the propofol PFS pump. The pharmacokinetic model of remifentanil described by Minto was incorporated into the Alaris PK infusion pump. Local effector, or biophase, concentrations corresponded to the information obtained from the infusion pumps and represented predictive measurements of the concentrations of both drugs on their sites of action. The concentrations of propofol and remifentanil were regulated according to BIS and MAP, respectively. Total intravenous anesthesia for ablation of AF can be a safe option considering the lack of electrophysiological changes in accessory pathways. The literature on this subject is scarce and new publications could justify, or not, this type of anesthesia during ablation of AF.

Cerebral protective effect of remifentanil preconditioning during cardiopulmonary bypass in patients undergoing coronary artery bypass grafting

Objective To investigate the cerebral protective effect of remifentanil preconditioning during cardiopulmonary bypass in patients undergoing coronary artery bypass grafting (CABG). Methods Forty ASA Ⅱ or Ⅲ patients of both sexes aged 55-64 yr weighing 50-85 kg undergoing elective CABG were randomized into 4 groups (n = 10 each) : control group (group C) and remifentanil groups (group R_1, R_2, R_3). Anasthesia was induced with midazolam 0.04 mg/kg, remifentanil 1 μg/kg, propofol 1 mg/kg and pipecuronium 0.1 mg/kg and maintained with isoflurane inhalation,intravenous continuous propofol infusion at 6-10 mg·kg~(-1)·h~(-1) and intermittent iv boluses of sufentanil and pipecurpnium after tracheal intubation. The patients were mechanically ventilated. P_(ET) CO_2 was maintained at 35-45 mm Hg. A catheter was inserted into internal jugular vein and advanced cranially until jugular bulb for blood sampling. The remifentanil groups received three 5 min episodes of iv remifentanil infusion at 0.6 μg/kg~(-1) ·min(-1) (group R_1),1.2μg/kg~(-1) ·min(-1)(group R_2) and 1.8μg/kg~(-1) ·min(-1)(group R_3) at 5 min intervals after induction of anesthesia before operation.Blood samples were obtained from jugular bulb before induction of anesthesia (T_0, baseline), before CPB (T_1), 30 min after initiation of CPB (T_2) and at the end of CPB (T_3) for determination of plasma S-100βprotein and MDA concentrations arid SOD activity. Results Plasma S-100β protein and MDA concentrations were significantly increased while plasma SOD activity was significantly decreased at T as compared with the baseline values at T_0 in all 4 groups. Plasma S-100β protein and MDA concentrations were significantly lower while plasma SOD activity was significantly higher at T_2 and T_3 in group R_3 than in the other 3 groups. Conclusion Preconditioning with larger doses of remifentanil (1.8 μg/kg~(-1) ·min(-1)) can attenuate brain injury induced by CPB in patient undergoing CABG through inhibiting oxidative stress response. Key words: Piperidines; Brain; Cardiopulmonary bypass; Coronary artery bypass

Results of a pilot study on the effects of propofol and dexmedetomidine on inflammatory responses and intraabdominal pressure in severe sepsis

Study Objective To compare the effects of an intravenous infusion of propofol and the alpha-2 adrenoceptor, dexmedetomidine, on inflammatory responses and intraabdominal pressure (IAP) in severe sepsis after abdominal surgery, specifically, serum cytokine levels (interleukin [IL]-1, IL-6, and tumor necrosis factor [TNF]-α) and IAP. Design Prospective, single-center study. Setting University hospital. Patients 40 adult ICU patients who had undergone ileus surgery and who were expected to require postoperative sedation and ventilation. Interventions Patients received either a loading dose infusion of propofol (Group P; n = 20) one mg/kg over 15 minutes followed by a maintenance dose of one to three mg/kg/hr (n = 20, Group P) or a loading dose of dexmedetomidine of one μg/kg over 10 minutes followed by a maintenance dose of 0.2-2.5 μg/kg/h (n = 20, Group D) at the 24th hour. Measurements Biochemical and hemodynamic parameters, cytokine levels, and IAP were recorded before the start of the study and at the 24th and 48th hours. Main Results TNF-α levels were significantly lower at the 24th hour (14.66 ± 4.40 pg/mL vs. 21.21 ± 11.37 pg/mL, respectively) and at the 48th hour (21.25 ± 15.85 pg/mL vs. 46.55 ± 35.99 pg/mL, respectively) in Group D. IL-1 levels were significantly lower at the 24th hour (5.03 ± 0.15 pg/mL vs. 6.23 ± 2.09 pg/mL, respectively) and the 48th hour (5.01 ± 0.37 pg/mL vs. 6.42 ± 2.76 pg/mL, respectively) in Group D. IL-6 levels were significantly lower at the 24th hour (253.1 ± 303.6 pg/mL and 511.3 ± 374.8 pg/mL, respectively) and at the 48th hour (343.5 ± 393.4 pg/mL and 503.7 ± 306.4 pg/mL, respectively) in Group D. Intraabdominal pressure also was significantly lower at the 24th hour (12.35 ± 5.84 mmHg vs. 18.1 ± 2.84 mmHg, respectively) and the 48th hour (13.9 ± 6.15 mmHg vs. 18.7 ± 3.46 mmHg, respectively) in Group D. Conclusion Dexmedetomidine infusion decreases TNF-a, IL-1, and IL-6 levels and IAP more than a propofol infusion.

The application and evaluation of propofol combined with ketamine bycontinous intravenous Infusion in infant surgery

Objective To assess propofol combined with ketamine anesthesia for surgery in infants of narcotic effect. Methods Anesthesia was maintained by continuous intravenous infusion of propofol 2～4 mg/kg and ketaminel ～2 mg/kg in 60 children, and atropine 0.02 mg/kg was given by the intramuscular injection before 30 minutes preoprative. The changes of the mean arterial pressure(MAP) ,heart rate(HR) ,pulse oxygen saturation(SpO2)and respiratory rate(RR) was observed. Results There was no significant difference between preoperative and different time during operation(P>0.05), and There was no significant difference between dif-ferent time during operation (P>0.05). Conclusion Continuous intravenous infusion of propofol combined with ketamine is safe and effective in infant surgery. The anesthetic effect was satisfied. Key words: Propefol; Ketamine ; Intravenous general anesthesia; Infant surgery