Intrathecal morphine reduces postoperative tramadol consumption in patients undergoing radical retropubic prostatectomy: a randomized trial.

BACKGROUND: Intrathecal (IT) morphine provides prolonged analgesia after major surgery. AIM: The aim of our study was to assess the impact of intrathecal morphine 200 µg on patient-controlled analgesia (PCA) tramadol consumptions and postoperative pain in patients who underwent radical retropubic prostatectomy (RRP) under general anesthesia. MATERIALS AND METHODS: In this prospective trial, 56 men who underwent radical retropubic prostatectomy (RRP) were randomized into 2 groups. Group M received intrathecal morphine (200 µg) before the induction of general anesthesia. Group C did not receive intrathecal morphine. Postoperative analgesia was provided with tramadol PCA. Pain scores, tramadol consumption, adverse effects, rescue analgesia were recorded. RESULTS: Total tramadol consumption at 24 hours and pain scores during 12 hours postoperatively were significantly lower in Group M compared with Group C (p < 0.05). Rescue analgesia and postoperative nausea were lower in Group M than in Group C (p < 0.05). CONCLUSIONS: Intrathecal morphine 200 µg provided a significant reduction in tramadol consumption, postoperative pain scores, rescue analgesia, and postoperative nausea after RRP without serious adverse effects.

Effects of preoperative gabapentin on postoperative pain after radical retropubic prostatectomy.

OBJECTIVE: The impact of preoperative gabapentin on tramadol consumption using patient-controlled analgesia (PCA) and postoperative pain was assessed in patients undergoing radical retropubic prostatectomy (RRP). METHODS: In this prospective, randomized trial, 51 patients undergoing RRP were randomized into two groups: the gabapentin group received 900 mg gabapentin orally 2 h before surgery; the control group did not receive gabapentin. Postoperative analgesia was provided by tramadol PCA. Pain was assessed using a visual analogue scale for 24 h, postoperatively. RESULTS: Mean cumulative tramadol consumption at 24 h was comparable in the two groups. Pain scores at 45 min, 60 min and 2 h postoperatively, and the number of patients who required rescue analgesia, were significantly lower in the gabapentin group than in the control group. Side-effects were similar in the two groups. CONCLUSIONS: Preoperative administration of 900 mg gabapentin did not decrease tramadol consumption, but was associated with lower pain scores in the early postoperative phase and a reduced need for rescue analgesia, compared with controls, in patients undergoing RRP.

Ondansetron does not block tramadol-induced analgesia in mice.

Tramadol is a weak opioid agonist and an inhibitor of the reuptake of noradrenaline and serotonin. This study was undertaken to assess a possible pharmacological interaction of ondansetron, a serotonin-3 (5-hydroxytryptamine-3, 5-HT3) antagonist, and tramadol in an animal model for acute pain. Sixty-three male albino mice were randomly given saline, tramadol (10, 20, and 40 mg kg(-1)), ondansetron (1, 2, and 4 mg kg(-1)), or ondansetron (1, 2, and 4 mg kg(-1)) and tramadol (20 mg kg(-1), given 10 min after ondansetron injection) intraperitoneally. Each mouse was assessed twice for tail-flick latency before saline or drug administration and 15, 30, 60, 90, and 120 min thereafter. Tramadol (10 mg kg(-1)) had no effect on pain threshold levels of mice, but tramadol doses of 20 or 40 mg kg(-1) increased pain threshold levels in a dose-dependent manner (p < 0.01 for 20 mg kg(-1) and p < 0.001 for 40 mg kg(-1)). Ondansetron doses of 1, 2, or 4 mg kg(-1) alone had no effect on pain threshold levels of mice. Tramadol (20 mg kg(-1)) and ondansetron (1, 2, and 4 mg kg(-1)) increased pain threshold levels at all doses (p < 0.001 for 1 and 2 mg kg(-1) ondansetron and p < 0.01 for 4 mg kg(-1) ondansetron). The pain threshold levels of mice given tramadol (20 mg kg(-1)) alone or tramadol and ondansetron (p > 0.05 for 1, 2, and 4 mg kg(-1)) were similar. Our results indicate that ondansetron-a 5-HT3 selective antagonist-does not decrease the analgesic effectiveness of tramadol in mice, which may be the result of different mechanisms involving 5-HT3 receptors.

Bioprocess intensification in flow-through monolithic microbioreactors with immobilized bacteria.

Microporous polymers (with porosity up to 90%) with a well-prescribed internal microstructure were prepared in monolithic form to construct a flow-through microbioreactor in which phenol-degrading bacteria, Pseudomonas syringae, was immobilized. Initially, bacteria was forced seeded within the pores and subsequently allowed to proliferate followed by acclimatization and phenol degradation at various initial substrate concentrations and flow rates. Two types of microporous polymer were used as the monolithic support. These polymers differ with respect to their pore and interconnect sizes, macroscopic surface area for bacterial support, and phase volume. Polymer with a nominal pore size of 100 microm with phase volume of 90% (with highly open pore structure) yielded reduced bacterial proliferation, while the polymer with nominal pore size of 25 microm with phase volume of 85% (with small interconnect size and large pore area for bacterial adhesion) yielded monolayer bacterial proliferation. Bacteria within the 25 microm polymer support remained monolayered, without any apparent production of extracellular matrix during the 30-day continuous experimental period. The microbioreactor performance was characterized in terms of volumetric utilization rate and compared with the published data, including the case where the same bacteria was immobilized on the surface of microporous polymer beads and used in a packed bed during continuous degradation of phenol. It is shown that at similar initial substrate concentration, the volumetric utilization in the microreactor is at least 20-fold more efficient than the packed bed, depending on the flow rate of the substrate solution. The concentration of the bacteria within the pores of the microreactor decreases from 2.25 cells per microm2 on the top surface to about 0.4 cells per microm2 within 3 mm reactor depth. If the bacteria-depleted part of the microreactor is disregarded, the volumetric utilization increases by a factor of 30-fold compared with the packed bed. This efficiency increase is attributed to the reduction of diffusion path for the substrate and nutrients and enhanced availability of the bacteria for bioconversion in the absence of biofilm formation as well as the presence of flow over the surface of the monolayer bacteria.

Bilateral CT-guided percutaneous cordotomy for cancer pain relief.

AIM: CT-guided percutaneous cordotomy is a useful procedure for treating unilateral cancer pain, however, bilateral cordotomy can be required on some occasions. We evaluated the effectiveness and complications of bilateral cordotomy. MATERIALS AND METHODS: Two hundred and thirty-four patients who suffered from unilateral cancer pain underwent CT-guided percutaneous cordotomy. The procedure was repeated in 22 patients, and nine patients had bilateral cordotomy. Effectiveness and complications were recorded after each procedure. RESULTS: Of nine patents (three women and six men) having bilateral percutaneous cordotomy in our study, four patients had mirror pain after the first procedure. In the remaining five patients the contralateral pain was due to new pain sites. The pain scores before and after the first procedure were 9.3 (range 7-10) and 1.2 (range 0-3), respectively. After the first procedure complete or satisfactory pain relief was achieved in all patients. The duration between the two procedures ranged from 7-243 days (mean 59.8 days). The pain scores before and after the second procedure were 8.4 (range 5-10) and 1.6 (range 0-4), respectively. After the second procedure complete or satisfactory pain relief was reported in all patients. There were no complications in four patients. One patient developed transient motor deficit after the first procedure. Other complications (nausea/vomiting, headache, ipsilateral neck pain, postcordotomy dysesthesia) were mild and transient. CONCLUSION: CT-guided percutaneous cordotomy is a useful procedure for the treatment of severe unilateral cancer pain syndromes. The procedure can be repeated on the other side at least 1 week later. These results show that the success on the second side appears to be similar to the first side with low complication rate for both procedures.

General anaesthesia or spinal anaesthesia for outpatient urological surgery.

BACKGROUND AND OBJECTIVE: A variety of drugs and techniques have been introduced into ambulatory anaesthesia. The technique as well as the drugs used may hasten or delay home discharge. We compared recovery profiles and side-effects of spinal anaesthesia and total intravenous anaesthesia. METHODS: Forty unpremedicated ASA I-II patients (18-65 yr) undergoing varicocele repair were randomly divided into two groups. Spinal anaesthesia (26-G atraumatic needle) with hyperbaric bupivacaine 0.5% 5 mg and fentanyl 25 microg were given to patients in Group Spinal (n = 20). Patients in Group TIVA (n = 20) received total intravenous anaesthesia with propofol and remifentanil given by continuous infusion; a laryngeal mask was used to secure the airway. The duration of surgery, time to home readiness and side-effects were recorded. RESULTS: The two groups were comparable with respect to patients' characteristics and duration of surgery. The times to achieve ambulation were similar between groups (Spinal = 78.4 +/- 40.9 min, TIVA = 75.9 +/- 13.8 min). Urinary voiding was a requirement for discharge after spinal anaesthesia and the time for home readiness was longer in Group Spinal (158.0 +/- 40.2 versus 94.9 +/- 18.8 min) (P < 0.05). Two patients reported pruritus and one reported postdural puncture headache in Group Spinal, whereas two patients reported nausea in Group TIVA. Patients in Group TIVA had a greater need for analgesia postoperation (P < 0.05). CONCLUSIONS: In healthy unpremedicated men undergoing minor urological operations, total intravenous anaesthesia with remifentanil and propofol provided as safe and effective anaesthesia as spinal block with the advantage of earlier home readiness.

Tracheal intubation without muscle relaxants: remifentanil or alfentanil in combination with propofol.

BACKGROUND AND OBJECTIVE: In some situations, the use of muscle relaxants (neuromuscular blocking drugs) are undesirable or contraindicated. We compared intubating conditions without muscle relaxants in premedicated patients receiving either alfentanil 40 microg kg(-1) or remifentanil 2, 3 or 4 microg kg(-1) followed by propofol 2 mg kg(-1). METHODS: In a randomized, double-blind study, 80 healthy patients were assigned to one of four groups (n = 20). After intravenous atropine, alfentanil 40 microg kg(-1) or remifentanil 2, 3 or 4 microg kg(-1) were injected over 90 s followed by propofol 2 mg kg(-1). Ninety seconds after administration of the propofol, laryngoscopy and tracheal intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of lung ventilation, jaw relaxation, laryngoscopy, position of the vocal cords, and patient response to intubation and slow inflation of the endotracheal tube cuff. RESULTS: Seven patients who received remifentanil 2 microg kg(-1) and one patient who received remifentanil 3 microg kg(-1) could not be intubated at the first attempts. Excellent intubating conditions (jaw relaxed, vocal cords open and no movement in response to tracheal intubation and cuff inflation) were observed in those who received either alfentanil 40 microg kg(-1) (45% of patients) or remifentanil in doses of 2 microg kg(-1) (20%), 3 microg kg(-1) (75%) or 4 microg kg(-1) (95%). Overall, intubating conditions were significantly better (P < 0.05), and the number of patients showing excellent conditions were significantly higher (P < 0.05) in patients who received remifentanil 4 microg kg(-1) compared with those who received alfentanil 40 microg kg(-1) or remifentanil 2 microg kg(-1). No patient needed treatment for hypotension or bradycardia. CONCLUSIONS: Remifentanil 4 microg kg(-1) and propofol 2 mg kg(-1) administered in sequence intravenously provided good or excellent conditions for tracheal intubation in all patients without the use of muscle relaxants.

Remifentanil versus alfentanil in total intravenous anaesthesia for day case surgery.

BACKGROUND AND OBJECTIVE: We assessed the intraoperative haemodynamic responses and recovery profiles of total intravenous anaesthesia with remifentanil and alfentanil for outpatient surgery. METHODS: Patients in Group 1 (n = 20) received alfentanil 20 microg kg(-1) followed by 2 microg kg(-1) min(-1) intravenously; patients in Group 2 (n = 20) received remifentanil 1 microg kg(-1) followed by 0.5 microg kg(-1) min(-1) intravenously. Both groups then received propofol 2 mg kg(-1) followed by 9 mg kg(-1) h(-1) intravenously. Five minutes after skin incision, infusion rates were decreased, and at the end of surgery, all infusions were discontinued. Early recovery was assessed by the Aldrete score, whereas intermediate recovery was assessed with the postanaesthetic discharge scoring system (PADS). RESULTS: Perioperative arterial pressure was similar in both groups; heart rate was lower in Group 2 (P < 0.05). The times to spontaneous and adequate respiration, response to verbal commands, extubation and times for Aldrete score > or = 9 were shorter in Group 2 patients (P < 0.05). Pain scores were higher in Group 2 patients (P < 0.05). Overall times for postanaesthetic discharge scores > or = 9 were similar. CONCLUSIONS: Early recovery of patients after day surgery is significantly shorter after total intravenous anaesthesia with remifentanil compared with that with alfentanil but postoperative pain management must be planned ahead.

The antinociceptive effect of moclobemide on the vocalization threshold to paw pressure in a rat model of unilateral mononeuropathy.

The aim of our study was to investigate the antinociceptive activity of moclobemide on the vocalization threshold to paw pressure in a rat model of unilateral mononeuropathy. The neuropathy was produced by ligation of the sciatic nerve and nociceptive thresholds were determined 15-21 days after surgery by a modification of the Randall-Sellito method. Group 1 (n= 10) received 0.2 ml peroral (p.o.) saline, Group 2 (n= 10) 5 mg x kg(-1), Group 3 (n= 10) 10 mg x kg(-1) and Group 4 (n= 10) 20 mg x kg(-1) p.o. moclobemide. Nociceptive pressure thresholds were then measured every 20 minutes after drug administration. Analysis of variance, Tukey's test and a paired Student's t-test were employed for statistical analysis. The perorally administered moclobemide (5, 10 and 20 mg x kg(-1)) produced an antinociceptive effect on both lesioned and non-lesioned hind paws ( P< 0.05). However, the analgesic effect on the lesioned paw was significantly more potent than the non-lesioned paw. The peak value ( p) remained constant while the maximal increment between the control threshold and the peak value ( I(max)) was significantly more pronounced for the lesioned paw ( P< 0.001). The results of this study may suggest that moclobemide can be a therapeutic alternative to treat some clinical symptoms in peripheral neuropathic conditions.

The antinociceptive effect of tramadol on a model of neuropathic pain in rats.

The antinociceptive activity of tramadol was investigated on the vocalization threshold to paw pressure in a rat model of unilateral mononeuropathy produced by loose ligatures around the common sciatic nerve. Despite the analgesic activity of tramadol was clearly established in motor and sensory responses of the nociceptive system in rats, the effect of this atypical opioid on experimental neuropathic pain models is not investigated. The intraperitoneally injected tramadol (2.5, 5 and 10 mg/kg) produced a potent and dose-dependent antinociceptive effect on both lesioned and non-lesioned hind paws. However, the analgesic effect on the lesioned paw was significantly more potent than the non-lesioned paw. This effect was partially antagonized by intraperitoneally administered naloxone (0.1 mg/kg) suggesting an additional non-opioid mechanism. Our results suggest that tramadol may be useful for the alleviation of some symptoms in peripheral neuropathic conditions

Comparison of topical silver nitrate and flunisolide treatment in patients with idiopathic non-allergic rhinitis.

In this study, 90 patients with idiopathic non-allergic rhinitis were divided into three groups. Silver nitrate was given to Group I, flunisolide to Group II, and placebo to Group III. Healing results according to symptoms, physical findings, nasal smear findings and biopsy findings were compared. Improvement ws noticed in symptoms (rhinorrhea 93%, sneezing 89%, nasal congestion 80%), physical findings (color of mucosa 89%, concha hypertrophy 87%, rhinorrhea 82%), nasal smear findings (94%) and biopsy findings (epithelium 76%, basal membrane 80%, edema 84%, eosinophilia 95%, inflammation 87%) in Group I. Recurrence was observed in symptoms and physical findings of 30% of the patients in Group I during the 6 months-follow-up period. In Group II, improvement was noticed in symptoms (rhinorrhea 73%, sneezing 70%, nasal congestion 61%), physical findings (color of mucosa 72%, concha hypertrophy 69%, rhinorrhea 62%), nasal smear findings (87%) and biopsy findings (epithelium 67%, basal membrane 63%, edema 70%, eosinophilia 77%, inflammation 70%). But symptoms recurred in all patients in approximately 1-3 months after competition of treatment. There was a statistically significant difference between silver treatment and flunisolide or placebo treatment.

Compensatory mechanisms in rats with nasal obstructions.

This study, in rats was designed to demonstrate the changes in respiratory dynamics in compensation for nasal obstructions. The experiment was performed on 30 rats. Fifteen rats served as the study group while another 10 rats served as controls. Five of the 30 rats were operated on to find out whether they would live and if so, for how long. Mouth breathing caused acute respiratory acidosis and marked aerophagia, leading to spontaneous death of the five experimental animals 90 to 100 hours postoperatively. Stenosis of the oropharyngeal airway due to palatal-epiglottic approximation, is supposed to be responsible for the respiratory insufficiency in nasally-obstructed rats. The compensatory changes in respiratory mechanics caused by high oropharyngeal airway resistance, together with some possible reflex changes, may have caused air swallowing. It is supposed that the increased air volume in the stomach and guts, causing elevation of the diaphragm and a paralytic ileus, contributed to mortality. No signs of aspiration were observed in these animals. After the surgical obstruction of both nostrils, changes in acid-base balance occurred in the 15 study rats 24, 48, and 72 hours postoperatively. On the first, second, and third days, a decrease in pO2 and pH, an increase in pCO2, and a compensatory increase in serum bicarbonate was observed.