Characterization of peripheral and central sensitization after dorsal root ganglion intervention in patients with unilateral lumbosacral radicular pain: a prospective pilot study.

BACKGROUND.: Quantitative sensory testing (QST) has been used to predict the outcome of epidural steroid injections in lumbosacral radicular pain and has the potential to be an important tool in the selection of appropriate treatment (such as epidural steroid injections vs surgery) for patients with chronic radicular pain. In addition, QST assists in identification of the pain pathways of peripheral and central sensitization in selected groups of patients. METHODS.: Twenty-three patients were given dorsal root ganglion (DRG) infiltration with local anaesthesia and steroid ('DRG block'), and those who demonstrated at least 50% pain relief were offered pulsed radiofrequency (PRF) to the DRG. Questionnaires and QST scores were measured before the DRG blocks and at 1 week and 3 months after their procedure. Those who received PRF also answered questionnaires and underwent QST measurements at 1 week and 3 months after their procedure. RESULTS.: There was a significant increase in pressure pain threshold scores after DRG blocks. A reduced conditioned pain modulation response was seen before DRG, which increased after the procedure. Ten out of 23 patients underwent PRF to the DRG, and an increase in pressure pain threshold scores after PRF was observed. The conditioned pain modulation response was maintained in this group and increased after PRF. CONCLUSIONS.: The study demonstrates that patients with unilateral radicular low back pain who receive dorsal root ganglion interventions show changes in pressure pain thresholds and conditioned pain modulation that are consistent with a 'normalization' of peripheral and central sensitization.

End-tidal sevoflurane concentration for ProSeal(TM) versus Classic(TM) laryngeal mask airway insertion in unpremedicated anaesthetised adult females.

The optimal end-tidal sevoflurane concentration for successful ProSealTM (Teleflex, Morrisville, NC, USA) laryngeal mask airway (PLMA) versus ClassicTM (Teleflex, Morrisville, NC, USA) laryngeal mask airway (CLMA) insertion in unpremedicated anaesthetised adults is unknown. We determined end-tidal sevoflurane concentrations for successful insertion in fifty percent of anaesthetised adults. This randomised, prospective, double-blind study was conducted in the operating theatre of a government tertiary care hospital. Forty-four unpremedicated American Society of Anesthesiologists physical status I and II women with cervical carcinoma (aged 30 to 60 years), scheduled for intracavity caesium implantation under general anaesthesia with a laryngeal mask airway (LMA) were included in the study. The participants were randomised to one of the two groups, to receive either a PLMA or CLMA. After anaesthetic induction with sevoflurane, a predetermined end-tidal sevoflurane concentration (starting at 2.5%) was sustained for 10 minutes before LMA insertion was attempted. End-tidal sevoflurane concentration was increased/decreased (step-size 0.25%) using Dixon and Massey's up-and-down method for the next patient based on the previous patient's response. Placement without clenching, movement, coughing or biting within one minute was considered successful insertion. The end-tidal sevoflurane concentration required for successful LMA insertion in fifty percent of anaesthetised adults was calculated as the mean of the crossover pairs' midpoints in each group and further confirmed by probit regression analysis. The end-tidal sevoflurane concentration (95% confidence interval) required for successful PLMA insertion in 50% of anaesthetised adults (3.15% [3.12% to 3.18%]) was significantly higher than that for CLMA insertion (2.71% [2.66% to 2.76%], P<0.001). These findings suggest that deeper anaesthesia is required for placement of a PLMA in comparison to a CLMA.

Effects of clonidine on recovery after sevoflurane anaesthesia in children undergoing cataract surgery.

This trial assessed the effects of two doses of clonidine compared with placebo on the quality and speed of recovery in children premedicated with oral midazolam and anaesthetised with sevoflurane for cataract surgery. One hundred and twenty American Society of Anesthesiologists physical status I to II children (aged one to six years), premedicated with oral midazolam 0.5 mg/kg and undergoing elective unilateral cataract surgery with sevoflurane anaesthesia were studied. Children were randomised to intravenous clonidine 1 microg/kg (group C1, n=39), 2 microg/kg (group C2, n=41) or normal saline (group NS, n=40). Clinically successful sub-Tenon local anaesthesia block was required for a patient to be included in the analysis. The primary outcome was the incidence of postoperative agitation. Postoperative agitation was defined as a Pain Discomfort Score of -3 using items 3 to 5 only, which was assessed 15 minutely until discharge. Agitation was observed in 11/40 (27.5%) children in the NS group compared to 2/39 (5.1%) in group Cl and none in group C2 (P < 0.001). Rescue medication to treat severe agitation was required in 5/40 (12.5%) in the NS group, 1/39 (2.6%) in group C1 and none in group C2 (P = 0.025). Time to meet discharge criteria was significantly shorter in group C1 compared to the other two groups (48.4 +/- 14.0 minutes compared to C2 79.5 +/- 12.8 minutes and NS 73.1 +/- 20.4 minutes, P < 0.001). There were no significant effects on blood pressure and heart rate. Intravenous clonidine 1 microg/kg is effective for reducing agitation after sevoflurane anaesthesia and midazolam premedication in children undergoing cataract surgery. Intravenous clonidine 2 microg/kg was also effective and for a longer period, but was associated with a longer time to discharge.

Patient-controlled epidural analgesia with fentanyl and bupivacaine provides better analgesia than intravenous morphine patient-controlled analgesia for early thoracotomy pain.

BACKGROUND: Intravenous patient-controlled analgesia (IVPCA) and patient-controlled epidural analgesia (PCEA) were studied in terms of analgesic efficacy, respiratory function and side effects after thoracic surgery for 24h. PCEA using fentanyl and bupivacaine as compared to IVPCA using morphine provides better pain relief both at rest and during coughing and is associated with fewer side effects. AIMS: To compare IVPCA and PCEA in terms of analgesic efficacy, respiratory function and side effects after thoracic surgery. SETTINGS AND DESIGN: Tertiary care teaching hospital. Prospective, randomized and open study. MATERIALS AND METHODS: Thirty ASA-I or II patients undergoing thoracotomy were assigned randomly to receive either IVPCA using morphine or PCEA using fentanyl and bupivacaine combination postoperatively. No background infusion was administered in either group. Postoperative evaluation included pain intensity both at rest and during coughing, degree of sedation, arterial blood gas, forced vital capacity (FVC), peak expiratory flow rate (PEFR), presence of side effects such as nausea/vomiting and pruritus at 0, 2, 8, 12 and 24h. The primary outcome of the study was the percentage of patients with analgesia failure defined as VAS>30 despite three consecutive PCA boluses requiring rescue analgesia with intravenous fentanyl. STATISTICAL ANALYSIS: Data were analyzed using t -test, chi2 test and Mann-Whitney test. RESULTS: Significantly less number of patients required rescue analgesia in PCEA group ( P< 0.05). Pain relief was better both at rest and during coughing ( P< 0.05) in PCEA group as compared to IVPCA. Patients in the PCEA group were less sedated and had fewer incidences of side effects, i.e. nausea/vomiting and pruritus. Postoperative FVC and PEFR were reduced significantly compared to baseline only in IVPCA group ( P< 0.05). CONCLUSION: After thoracic surgery, PCEA using fentanyl and bupivacaine as compared to IVPCA using morphine provides better pain relief both at rest and during coughing and associated with fewer side effects.

Neostigmine does not prolong the duration of analgesia produced by caudal bupivacaine in children undergoing urethroplasty.

CONTEXT: Neostigmine extends the duration of analgesia produced by caudal bupivacaine in children. AIMS: To study the effect of different doses of caudal neostigmine on the duration of postoperative analgesia. SETTINGS AND DESIGN: A randomized, double-blind study was conducted in 120 boys aged 1-12 years undergoing urethroplasty under combined general and caudal anesthesia. MATERIALS AND METHODS: Children were administered 1.875 mg/kg bupivacaine alone (Group B) or with 2, 3 or 4 microg/kg of neostigmine (groups BN 2, BN 3 or BN 4 respectively) as caudal drug (0.75 ml/kg). Children with a pain score of 4 or more (OPS and NRS) postoperatively were administered rescue analgesic. Time to first analgesic and the number of analgesic doses administered in the 24h were recorded. STATISTICAL ANALYSIS: Parametric data were analyzed using ANOVA. Kaplan-Meier survival curves for the time to first analgesic administration were plotted and compared using log rank analysis. Chi-square test was used to analyze the incidence data. RESULTS: The median [IQR] time to first analgesic in Group B (540 [240-1441] min) was similar to that in Groups BN 2 (450 [240-720]), BN 3 (600 [360-1020]) and BN 4 (990 [420-1441]). Significantly more patients in Groups B (9 [34.6%]) and BN 4 (13 [44.8%]) required no supplemental analgesic for 24h than those in Groups BN 2 and BN 3 (4 [13.8%] and 4 [13.3%]). The number of analgesic doses required in 24h in the four groups was similar. CONCLUSION: Addition of neostigmine to 1.875 mg/kg of caudal bupivacaine did not prolong the analgesia following urethroplasty in children.

Effect of scalp block on postoperative pain relief in craniotomy patients.

The efficacy of scalp nerve block using 0.5% bupivacaine with adrenaline for postoperative pain relief in craniotomy patients was evaluated in 40 ASA I or II adult patients undergoing supratentorial craniotomy. A standard general anaesthesia technique was followed. Patients were randomly divided into two groups. Group B received 0.5% bupivacaine with 1:400,000 adrenaline and group S received normal saline with 1:400,000 adrenaline, both after skin closure. Postoperative pain was assessed at 30 seconds and 1, 2, 4, 6, 8 and 12 hours using a numerical rating scale. Diclofenac IM was administered as rescue analgesia if patients reported a numerical rating scale of 40 or more. Tramadol IV was administered as second rescue analgesia. Sixty per cent of patients in group S experienced moderate to severe pain (numerical rating scale of 40 or more) at some time during the first 12 postoperative hours in comparison to 25% patients in group B. Median pain scores were significantly lower in group B for up to 6 hours. Significantly more patients were pain free up to four hours in group B. Median duration for the requirement of first dose of diclofenac was longer in group B compared to group S (360 min vs 30 min, P < 0.01). The number of doses of diclofenac (5 vs 19) was significantly lower in group B compared to group S (P < 0.01). Tramadol was required by six patients in group S only. Scalp nerve block using 0.5% bupivacaine with 1:400,000 adrenaline decreases the incidence and severity of postoperative pain in patients undergoing supratentorial craniotomy.

Complex regional pain syndrome: a review.

Complex regional pain syndrome (CRPS) is a challenging neuropathic pain state, quite difficult to comprehend and treat. Its pathophysiological mechanisms are unclear and its treatment is difficult. Multiple factors play a role in the generation and maintenance of CRPS. A close interdisciplinary collaboration amongst the psychologist, physical and occupational therapists, neurologist and pain medicine consultants is necessary to achieve optimal treatment effects. The primary goals of managing patients with this syndrome are to: 1) perform a comprehensive diagnostic evaluation, 2) be prompt and aggressive in treatment interventions, 3) assess and reassess the patient's clinical and psychological status, 4) be consistently supportive, and 5) strive for the maximal amount of pain relief and functional improvement. This article reviews the different aspects of CRPS including definition, classification, epidemiology and natural history, clinical presentation, pathophysiology and management.

A comparison of intravenous ketoprofen versus pethidine on peri-operative analgesia and post-operative nausea and vomiting in paediatric vitreoretinal surgery.

AIM: To compare the efficacy of ketoprofen and pethidine for peri-operative analgesia and post-operative nausea and vomiting in children undergoing vitreoretinal surgery and surgery for retinal detachment. MATERIAL AND METHODS: Children aged 7 to 16 years and ASA I status, undergoing vitreo-retinal surgery were randomly allocated to receive either ketoprofen 2mg/kg or pethidine 1mg/kg intravenously for peri-operative analgesia. In all patients, general anaesthesia was induced with thiopentone and intubation was facilitated with vecuronium bromide and maintained with 33% oxygen in nitrous oxide and isoflurane. Intra-operative and post-operative monitoring was done by an observer blinded to the technique. Intra-operative rescue analgesia was used if heart rate and/or blood pressure increased by 25% from pre-incision values. Post-operative pain and episodes of nausea and vomiting were evaluated at recovery (0 hour), 2, 6 and 24 hours intervals. Standard rescue analgesia and anti-emetic agents were administered if required. RESULTS: Eighty-six children were enrolled in the study. Forty-four received ketoprofen while 42 received pethidine. Intra-operative analgesia was comparable in both the groups and no significant difference was found in the requirement of intra-operative rescue analgesia, as well. Postoperatively 6/44 (13.6%) children in ketoprofen group had pain at recovery compared to 17/42 (40.4%) in pethidine group. Pain at 2, 6 and 24 hours, and postoperative analgesic requirement were not significantly different among the two groups. Post-operative nausea, vomiting, and antiemetic requirement were significantly less in the ketoprofen group at all time intervals. CONCLUSION: Ketoprofen is a satisfactory alternative analgesic to pethidine for vitreoretinal surgery and results in a lower incidence of postoperative nausea and vomiting.

Massive intraabdominal extravasation of fluid: a life threatening complication following percutaneous nephrolithotomy.

Percutaneous nephrolithotomy provides an attractive alternative to the surgical removal of renal stones as it is associated with reduced patient morbidity and shortened hospital stay. The advantages of this procedure may, however, be overshadowed by complications like bleeding, extravasation of irrigant fluid and infection, which can be life threatening. We report a case of massive extravasation of irrigant fluid producing severe metabolic acidosis, persistent peritonism and ileus leading to a prolonged hospital stay. The patient also required a further surgery for the complete removal of the stones.

Epidural anesthesia for cesarean section in a patient with Eisenmenger's syndrome.

Eisenmenger's syndrome is a complex combination of cardiovascular abnormalities and is defined as pulmonary hypertension at systemic pressure level with reversed or bi-directional shunt through an intracardiac or aortopulmonary communication. Patients with Eisenmenger's syndrome are at high risk for peripartum morbidity and mortality. Multigravid patients with this disease are therefore uncommon. We report the anesthetic management for cesarean section of a 27-year-old multigravid female at 35 weeks' gestation with Eisenmenger's syndrome. Titrated epidural anesthesia was administered with incremental doses of 2% lidocaine. Intraoperative course was uneventful except for an episode of hypotension immediately after delivery of the baby, which was managed successfully. We conclude that carefully titrated epidural anesthesia may be safe, appropriate, and effective for patients with Eisenmenger's syndrome for cesarean section.

Comparative evaluation of intraocular pressure changes subsequent to insertion of laryngeal mask airway and endotracheal tube.

AIMS: To evaluate the intraocular pressure and haemodynamic changes subsequent to insertion of laryngeal mask airway and endotracheal tube. SUBJECTS AND METHODS: The study was conducted in 50 adult patients. A standard general anaesthesia was administered to all the patients. After 3 minutes of induction of anaesthesia baseline measurements of heart rate, non-invasive blood pressure and intraocular pressure were taken following which patients were divided into two groups: laryngeal mask airway was inserted in group 1 and tracheal tube in group 2. These measurements were repeated at 15-30 second, every minute thereafter up to 5 minutes after airway instrumentation. RESULTS: A statistically significant rise in heart rate, systolic blood pressure, diastolic blood pressure and intraocular pressure was seen in both the groups subsequent to insertion of laryngeal mask airway or endotracheal tube. Mean maximum increase was statistically more after endotracheal intubation than after laryngeal mask airway insertion. The duration of statistically significant pressure responses was also longer after endotracheal intubation. CONCLUSION: Laryngeal mask airway is an acceptable alternative technique for ocular surgeries, offering advantages in terms of intraocular pressure and cardiovascular stability compared to tracheal intubation.