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Background. The purpose of this prospective, double-blinded randomized control pilot study was to evaluate the effect of adjunctive dexamethasone on analgesia duration and the incidence of postoperative neuropathic complication. Peripheral nerve blocks are an effective adjunct to decrease postoperative pain in foot and ankle surgery, and any possible modalities to augment their efficacy is of clinical utility. Methods. Patients were randomly assigned to a control group (n = 25) receiving nerve blocks of bupivacaine and epinephrine or an experimental group (n = 24) with an adjunctive 8 mg dexamethasone. The patients, surgeons, and anesthesiologists were all blinded to allocation. Patients had a minimum 1 year postoperative follow-up. Results. Forty-nine patients completed the protocol. There was no statistically significant difference in analgesia duration ( P = .38) or postoperative neuropathic complication incidence ( P = .67) between the 2 groups. Conclusions. The addition of dexamethasone to popliteal nerve blocks does not appear to affect analgesia duration or incidence of postoperative neuropathic complications. However, our study was underpowered, and we recommend a larger scale prospective study for validation.Levels of Evidence: Level II: Prospective, randomized control pilot study

Objective To investigate the efficacy of low-dose sufentanil for preventing shivering and visceral traction pain during cesarean section under spinal anesthesia. Methods This was a prospective, randomized, controlled study. A total of 112 full-term parturients who underwent elective caesarean delivery were randomly divided into two groups. Group R received 0.75% isobaric ropivacaine intrathecally and group RS received 0.75% isobaric ropivacaine plus 5 µg sufentanil intrathecally. Results There were no significant differences in the maximum sensory block time, motor block time, duration of the surgery, and heart rate, mean arterial pressure, and blood oxygen saturation before and 1, 5, and 10 minutes after spinal anesthesia, and at the end of the surgery between the two groups. Shivering was significantly more common in group R (n = 30) than in group RS (n = 8). The incidence of visceral traction pain in group R (46.43%) was significantly higher than that in group RS (14.29%). There was no significant difference in the newborns’ Apgar scores between the groups. Conclusion Adding low-dose sufentanil to ropivacaine can significantly reduce the incidence of shivering and visceral traction pain after spinal anesthesia.

Background There is increasing evidence to support the use of anesthetics to affect operative fields during endoscopic sinus surgery and thus the speed, thoroughness, and safety of the surgery itself. Previous research has suggested preoperative beta-blockers improve surgical fields (SFs); our study is novel in showing the impact of a beta-blocker infusion on SFs during sinus surgery. Methods A prospective, randomized, double-blind, placebo-controlled trial was conducted in 40 patients. Patients undergoing endoscopic sinus surgery for chronic rhinosinusitis received a constant infusion of i.v. esmolol or saline in addition to a standard inhaled anesthetic protocol. At regular 15-minutes intervals, the quality of SF, heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were assessed. Total blood loss was also recorded. Results Average vital sign parameters (HR/SBP/DBP) were significantly lower in the esmolol group (69.1/90.2/55.1 versus 77.2/99.5/63.5; p < 0.01). The esmolol infusion improved SFs relative to control (2.3 versus 2.6; p = 0.045). Esmolol infusion resulted in good SFs (grades 1 and 2) more often than poor fields (grades 3 and 4); on the contrary, the control group showed more poor than good SFs (chi-square; p = 0.04). A correlation between increasing HR and worsening SFs was identified (r = 0.259; p = 0.002). The control group had significantly higher average blood loss (1.3 versus 0.8 mL/min; p = 0.037). Conclusion Esmolol-induced relative hypotension and bradycardia during endoscopic sinus surgery achieves significantly improved SFs relative to saline control.

Fast recoveries are essential when looking for a safe anaesthetic protocol to use on mice. Propofol is a short-acting anaesthetic agent, which provides a smooth, fast recovery. A recent study carried out in our laboratory showed that the intraperitoneal (i.p.) administration of propofol combined with a fast-acting opioid does not provide a sufficiently stable anaesthesia. In this experiment, we hypothesized that the additional application of medetomidine would increase muscle relaxation and analgesia. Fifty-four male CD1 mice, divided into six groups of five and three groups of eight, were used to test nine different combinations of propofol, medetomidine and fentanyl administered i.p. and reversed with atipamezole 30 min after induction. These combinations were composed in the following manner: propofol 75 mg/kg, medetomidine 1 and 2 mg/kg and fentanyl 0.1, 0.15 and 0.2 mg/kg. The depth of anaesthesia, loss of righting reflex, loss of pedal withdrawal reflex, pulse rate and respiratory rate were recorded along with the duration and quality of the recovery. The combination of propofol and medetomidine provided a predictable induction, hypnosis and muscle relaxation, but surgical anaesthesia (loss of pedal withdrawal reflex) was not achieved. The addition of fentanyl increased analgesia leading to surgical anaesthesia. We concluded that a combination of 75/1/0.2 mg/kg of propofol, medetomidine and fentanyl, respectively, is a safe, easy and reversible technique for i.p. anaesthesia in mice, providing a surgical window of 15 min and restraint for 30 min with a fast recovery.

This study investigated whether the addition of 25 μg intrathecal fentanyl to levobupivacaine spinal anaesthesia for outpatient inguinal herniorrhaphy allows a sub-anaesthetic levobupivacaine dose to be used. Forty patients were assigned to receive 5 mg levobupivacaine 0.5% mixed with 25 μg fentanyl (group LF) or 7.5 mg levobupivacaine 0.5% (group L). The highest sensory block levels achieved were T7 (range T5 – T9) and T6 (range T4 – T9) in groups LF and L, respectively. The times to two-segment regression, S2 regression, ambulation, urination and discharge were all significantly shorter in group LF than group L. These results indicate that, for outpatient inguinal herniorrhaphy, intrathecal fentanyl combined with low-dose levobupivacaine provides good quality spinal anaesthesia and minimizes the need for intra-operative analgesia. This protocol is well suited for the outpatient setting because it features rapid recovery of full motor power, sensory function and bladder function.

Background:Preventing significant oxygen desaturation and hypotension through adequate analgesia and sedation during nonemergent Intubation In neonates is desirable. However, in many neonatal intensive care units, elective intubations occur without adequate premedication. There is significant variation In the choice of premedication agen(s) and doses, and an ideal regimen for use during nonemergent intubation has not been developed.Objective:To evaluate the efficacy of an algorithm developed for analgesia and sedation during nonemergent Intubation in neonates.Methods:Prospectively collected continuous quality Improvement data on a premedication algorithm for nonemergent intubation were analyzed following institutions] review board approval. Midazolam 0.1 mg/kg and fentanyl 2 μg/kg (if the patient was not already receiving morphine for sedation) were administered prior to nonemergent intubation. Heart rate, oxygen saturation, respiration rate, mean arterial pressure, and pain scores were recorded at baseline prior to medication administration, during the procedure, and for 2 hours after the procedure. Data during laryngoscopy and until the time of lube taping were obtained from Ine bedside cardiorespiratory monitor. Additional fentanyl was allowed for more than 3 intubation attempts and rocuronium 0.6 mg/kg was allowed for more than 5 attempts. The physiological changes that occurred over time were compared with baseline. The number of attempts made, time to intubation, and medications used are presented.Results:Ninety evaluable patients were included. Mean ± SD birth weight and postnatal age at treatment were 2040 ± 961 g and 14 ± 17 days, respectively. Heart rate decreased and oxygen saturation Increased significantly (160 vs 154 beats/min, p = 0.01; 96.4% vs 93.8%. p = 0.002, respectively) from baseline to completion of the procedure; however, mean arterial pressure showed no significant difference (44.9 vs 44.7 mm Hg; p = 0.85; n = 68). The number of attempts at Intubation were recorded (or 66 patients; of those, 52 required 3 or fewer attempts for successful Intubation (median, 2).The lime to successful intubation was 7.2 ± 5.6 minutes (recorded in 45 pts.). Average fentanyl and midazolam doses were 1.92 ± 0.53 μg/kg and 0.096 ± 0.026 mg/kg, respectively. No patient received rocuronium.Conclusions:A systematic approach to premedication during nonemergent intubation successfully prevented acute physiological changes.

Intrathecal midazolam binds with gamma aminobutyric acid-A receptors in the spinal cord leading to an analgesic effect. Clinical studies suggested that intrathecal midazolam may also reduce nausea and vomiting when used as an adjunct to other spinal medications. However, the potential neurotoxic effect of intrathecal midazolam remains a concern. This meta-analysis aims to evaluate the effectiveness and side-effects of intrathecal midazolam in the perioperative and peripartum settings. Thirteen randomised controlled studies from MEDLINE (from 1966 to July 1 2007), EMBASE and Cochrane Controlled Trials Register databases, involving a total of 672 patients, were considered. Volunteer, animal and chronic pain studies were excluded. Adding intrathecal midazolam to other spinal medications reduced the incidence of nausea and vomiting (odds ratio 0.50, 95% confidence interval [CI] 0.27 to 0.90, P=0.02; I 2 =4%) and delayed the time to request for rescue analgesia (weighted-mean-difference=98.7 min, 95% CI: 76.1 to 121.4, P 2 =94.8%). The incidence of neurological symptoms after intrathecal midazolam was uncommon (1.8%) and did not differ from placebo (odds ratio 1.20, 95% CI 0.22 to 6.68, P=0.84). Based on the limited data available, intrathecal midazolam appears to improve perioperative analgesia and reduce nausea and vomiting during caesarean delivery. A multicentre registry or large randomised controlled study with a prolonged follow-up period would be useful to confirm the clinical safety of intrathecal midazolam.

BACKGROUND: There is considerable debate regarding the appropriateness of feeding patients by the enteral route in conjunction with pentobarbital coma therapy. OBJECTIVE: To determine the incidence of feeding intolerance (FI) in patients receiving pentobarbital in conjunction with enteral nutrition (EN). METHODS: A retrospective, observational evaluation of patients (>14 y of age) who received a therapeutic pentobarbital coma in combination with EN was conducted. Patients were divided into groups, based on the occurrence of FI defined as aspiration of gastric residuals greater than 75 mL for 2 consecutive measurements. RESULTS: Forty-eight percent (29 of 61) of patients experienced FI based on our definition. The median pentobarbital infusion rate did not differ significantly between patients who experienced FI versus those who did not (median [intraquartile range, IQR] 1.8 mg/kg/h [1.4, 2.1] vs 1.7 mg/kg/h [1.4, 2.5]; p = 0.680). The total pentobarbital bolus dose during the first 24 hours of therapy was lower in patients who experienced FI (700 mg [225, 980] vs 1000 mg [600, 1475]; p = 0.029). Median duration of pentobarbital therapy was comparable between groups (141.0 h [93.3, 217.3] vs 116.3 h [64.0, 174.8]; p = 0.115). Other factors with the potential to influence FI, such as catecholamines, neuromuscular blockade, and hyperglycemia, were similar between groups. The higher narcotic doses and greater percentage of patients receiving benzodiazepines in the FI group warrants further study. CONCLUSIONS: Pentobarbital therapy did not preclude use of EN in the entire study population. In addition, FI did not occur at a greater frequency in patients who received a higher dosage, a longer duration, or an earlier initiation of pentobarbital therapy.

The combination of propofol and a rapid-acting opioid, such as fentanyl, sufentanil or remifentanil, is a relatively safe, total intravenous anaesthesia technique, commonly used in humans and which has been investigated in laboratory animals. The objective of this study was to evaluate these combinations for anaesthesia of mice by the intraperitoneal (i.p.) route. Sixty-seven mice, divided into groups of four, were used to test 28 combinations of propofol alone and propofol with fentanyl, sufentanil or remifentanil administered i.p. The dose ranges of drugs studied were propofol 50–200 mg/kg, fentanyl 0.2–0.4 mg/kg, sufentanil 0.05–0.1 mg/kg and remifentanil 0.2–1.0 mg/kg. The loss of righting reflex (RR) and the loss of pedal withdrawal reflex (PWR) were recorded along with the duration and quality of recovery. The results obtained in these studies were unpredictable. The same dose combinations of propofol and opioids were associated with different responses in different individuals. Higher doses did not induce loss of RR and PWR in all animals and were associated with high mortality rates. An adequate hypnotic level was only observed with higher doses of propofol. The synergistic effect of propofol and the opioids was not sufficient to allow surgical procedures. Animals that reached PWR loss showed tail rigidity, shaking limbs and scratched their heads with their forefeet. Higher opioid doses induced respiratory depression and higher death rates. The inconsistency between and within groups may be associated with the i.p. route. The results reported here show that the i.p. route is not appropriate for mouse anaesthesia using propofol alone or in combination with fentanyl, sufentanil or remifentanil.

The objective of this work was to evaluate the physiological and behavioural effects of opioid analgesic treatment in pigs subjected to abdominal surgery. Ten Swedish Landrace x Yorkshire pigs (20 +/- 4 kg b.w.) were submitted for intestinal cannulation. The pigs were allocated into two groups during one preoperative, one surgical and two postoperative days. All pigs were anaesthetized with medetomidine, tiletamine and zolazepam. One group was treated with epidural morphine (0.1 mg/kg) preoperatively, and transdermal fentanyl patches (50 microg/kg/h) were applied behind the ear immediately after surgery. The other group received epidural saline (equivalent volume) and placebo patches. All pigs were regularly weighed and clinically examined and repeated blood samples were analysed for serum concentrations of cortisol, beta-endorphin and fentanyl. Pre- and postoperative behaviours were evaluated by a swine specialist blinded to the treatment, three times a day, and were also videotape recorded for a total of 84 h per pig. No differences in behaviour were noted by the observer. During the first postoperative 12 h, treated pigs did not differ in activity compared with preoperative recordings, while untreated pigs were found to be less active. The treated group started to show interest in eating immediately after anaesthesia recovery, whereas the placebo group did not. During the 12-60 h postoperative period, the treated group had lower activity levels compared with the preoperative levels, which were similar to those in the placebo group. Treated pigs gained 0.5 +/- 0.2 kg during the subsequent two postoperative days, whereas the untreated pigs lost weight throughout the experiment. Cortisol concentration differed immediately after the surgery: Group P had 325 +/- 120 nmol/L and Group M 159 +/- 49 nmol/L. beta-endorphin concentration did not differ between groups. The highest serum fentanyl concentration (0.37 +/- 0.3 ng/mL) was measured 24 h postoperatively. Preoperative epidural morphine in combination with postoperative transdermal fentanyl resulted in earlier return to normal activity levels and an immediate weight gain after surgery.

The aim of this prospective, double-blind, randomized, placebo-controlled clinical trial was to investigate whether the administration of ketamine before induction with propofol improves its associated haemodynamic profile and laryngeal mask airway (LMA) insertion conditions. Ninety adult patients were randomly allocated to receive either ketamine 0.5 mg.kg-1 (n=30), fentanyl 1 μg.kg-1 (n=30) or normal saline (n=30), before induction of anaesthesia with propofol 2.5 mg.kg-1. Insertion of the LMA was performed 60s after injection of propofol. Arterial blood pressure and heart rate were measured before induction (baseline), immediately after induction, immediately before LMA insertion, immediately after LMA insertion and every minute for three minutes after LMA insertion. Following LMA insertion, the following six subjective endpoints were graded by a blinded anaesthestist using ordinal scales graded 1 to 3: mouth opening, gagging, swallowing, movement, laryngospasm and ease of insertion. Systolic blood pressure was significantly higher following ketamine than either fentanyl (P=0.010) or saline (P=0.0001). The median (interquartile range) summed score describing the overall insertion conditions were similar in the ketamine [median 7.0, interquartile range (6.0–8.0)] and fentanyl groups [median 7.0, interquartile range (6.0–8.0)]. Both appeared significantly better than the saline group [median 8.0, interquartile range (6.75–9.25); P=0.024]. The incidence of prolonged apnoea (>120s) was higher in the fentanyl group [23.1% (7/30)] compared with the ketamine [6.3% (2/30)] and saline groups [3.3% (1/30)]. We conclude that the addition of ketamine 0.5 mg.kg–1 improves haemo-dynamics when compared to fentanyl 1 μg.kg–1, with less prolonged apnoea, and is associated with better LMA insertion conditions than placebo (saline).

We studied patients with valvular heart disease to investigate whether chronic pre-operative treatment with angiotensin-converting enzyme (ACE) inhibitors modulates the effect of phenylephrine (PE) on anaesthesia-induced hypotension. Sixty-five patients were enrolled in the study and hypotension developed after anaesthesia in 36 (18 in the control group and 18 in the ACE inhibitor group). These patients received PE infusions, which were increased in a stepwise fashion at 10-min intervals. Increased mean arterial pressure due to PE infusion was significant only in the control group. There was no significant difference in pressor response or change in haemodynamic variables with PE infusion between the two groups. Treatment with ACE inhibitors did not increase the incidence of hypotensive episodes or significantly modify pressor response after anaesthesia in patients with valvular heart disease.

The effects of sodium nitroprusside (SNP), a potent hypotensive agent, on cerebral blood flow (CBF) have been extensively studied in clinical and experimental situations but the results remain controversial. Whereas its properties would predict a dilatation of cerebral blood vessels, most studies report either no change or a decrease in CBF. The aim of this study was to investigate the effects of SNP on CBF, cerebral blood volume (CBV), and cerebral oxygen metabolism (CMRO2), by means of positron emission tomography in the anaesthetized baboon. Measurements were performed during normotension (mean arterial pressure (MABP): 97±16 mm Hg) and repeated following SNP-induced hypotension (MABP: 44±9 mm Hg). Sodium nitroprusside led to an increase in CBF and CBV (+30% and +37%, respectively, P2 was noted. Linear regression analysis of CBF values as a function of MABP confirmed that CBF increases when MABP is reduced by SNP. The comparison between these cerebrovascular changes and those found during trimetaphan-induced hypotension in our previously published studies further argues for a direct dilatatory effect of SNP on cerebral blood vessels.

This randomized controlled trial was designed to evaluate whether the combination of low dose oral midazolam (0.25 mg/kg) and low dose oral ketamine (3 mg/kg) provides better premedication than oral midazolam (0.5 mg/kg) or oral ketamine (6 mg/kg). Seventy-eight children of ASA physical status I or II scheduled for elective ophthalmic surgery were randomly divided into three groups and given premedication in the holding area 30 minutes before surgery. Two subjects from each group vomited the medication and were excluded, leaving 72 subjects for further analysis. The onset of sedation was earlier in the combination group than the other two groups. At 10 minutes after premedication 12.5% in the combination group had an acceptable sedation score compared with none in the other two groups. After 20 minutes 54% in the combination group had an acceptable sedation score, 21% in the midazolam group and 16% in the ketamine group (P

We investigated the effect of midazolam pre-medication on rocuronium-induced neuromuscular blockade during sevoflurane anaesthesia. Twenty-two patients scheduled for elective surgery were randomly divided to receive either no pre-medication (control group) or pre-medication with 0.1 mg/kg midazolam intramuscularly (midazolam group). Anaesthesia was induced with fentanyl and propofol, and maintained with sevoflurane and nitrous oxide in oxygen. Neuromuscular responses were monitored using acceleromyography. The onset and clinical duration of action, time to recovery of first twitch of train-of-four (TOF) response to 75% of control, recovery index and time for TOF recovery to 25% and 50% were recorded. Patient-related data were similar in both groups. The parameters recorded were not significantly different between the groups. Midazolam pre-medication does not influence the time-course of action of rocuronium during sevoflurane anaesthesia.

A mere glance at a BNF will demonstrate the huge variety of drugs which are now available to us. In this piece, Rachelle Griffiths takes us step by step through the basics of anaesthetic drugs. I am very aware of the enormity of this topic, and would recommend that you take the time to consider carefully the information provided in this piece. There will be further articles on drugs and their effects in this series.

Successful administration of anesthesia in endoscopic sinus surgery is of critical importance for patient comfort, to reduce bleeding, and for procedure safety. However, surgeons are often reluctant to perform the procedure under local anesthesia with sedation. Over the past four years, patients undergoing ESS have been asked to complete a questionnaire to evaluate their anesthetic experience. A total of 111 completed questionnaires were returned for evaluation. The questionnaire evaluated subjective level of pain, nausea, vomiting, and overall unpleasantness of surgery on a 100 mm visual analog scale. The results from this survey indicate a high level of patient satisfaction with our current anesthetic techniques, while identifying issues with postoperative nausea and vomiting. The results of the survey and a review of the anesthetic issues involved in successfully performing endoscopic sinus surgery are discussed.

The aim of the study was to compare three anaesthetic agents in patients with ejection fraction below 0.40 subjected to coronary revascularization surgery. Twenty-five elective coronary surgical patients with ejection fraction below 0.40 were prospectively studied. Premedication was pethidine 1 mg/kg and induction was fentanyl 0.03 mg/kg and pancuronium 0.1 mg/kg. The patients were randomized to one of three maintenance techniques (fentanyl, isoflurane or halothane). Radial arterial pressure, heart rate, right atrial pressure, pulmonary arterial and occluded pressures, and thermo-dilution cardiac output were measured, and cardiac index and resistance calculated, at the following times: before induction; 5 min after intubation; 2 min after sternotomy; immediately after discontinuation of bypass; 15 min afterwards; immediately after sternal closure; during suture of the skin; 5 min after arrival in the postoperative care unit; and 60 min postoperatively. Mean arterial pressure decreased significantly in the isoflurane group and nonsignificantly in the halothane group after induction. Cardiac index decreased significantly in the isoflurane group and nonsignificantly in the halothane group after induction and after sternotomy. Neither pressure nor flow decreased in patients receiving fentanyl. Following weaning from cardiopulmonary bypass, systemic vascular resistance decreased significantly in all groups. Cardiac index, however, did not increase above control values and arterial pressure consequently decreased; there was no significant difference between groups.

We report a case of intracerebral haemorrhages associated with continuous spinal analgesia. Continuous spinal analgesia is frequently employed for postoperative analgesia in high-risk patients in our institution. The analgesia is administered via a 20 gauge catheter passed through an 18 gauge Tuohy needle (Portex). A 71-year-old man with severe respiratory impairment had an intrathecal catheter placed for postoperative analgesia. He had a difficult postoperative course, including wound dehiscence, and died from respiratory failure some five weeks postoperatively. On day nine postoperatively he had two tonic-clonic seizures and was subsequently found to have developed bilateral frontal intracerebral haemorrhages. There was no previous history of seizures. Although several confounding variables exist, the most likely explanation for the intracerebral event appears to be an association with the dural puncture and intrathecal catheter. Possible mechanisms and risk factors are discussed.

The effects of the fluorinated benzodiazepine compound flunitrazepam were studied in eighty patients. The drug was administered intravenously in a standard dose of 2 mg, 3 mg, or 4 mg to supplement lumbar epidural analgesia. Induction was smooth and pleasant. The sleep onset time was dose related and exceeded one minute in the majority of patients. Sleep was invariably produced in patients receiving 4 mg but at lower dosage some patients failed to become unconscious. Pain in the arm during injection was a common feature. The respiratory rate was slightly increased, but in two patients apnoea occurred at induction. The cardiovascular system was minimally depressed with a small decrease in systolic blood pressure and pulse rate. Recovery from sleep was slow but sequelae were minimal. The sedative and amnesic properties contributed significantly to the high rate of patient acceptance.

The pharmacokinetics of alfentanil, a new and very short-acting opioid, are discussed. Its use in day-case gynaecological procedures is described, and the results of the initial study presented. Alfentanil is a valuable adjunct to anaesthesia for day-case surgery and for short, painful procedures.