Summary

Chronic pain represents a major public health problem that impacts negatively on quality-of-life issues and healthcare costs. Unrelieved acute post-traumatic and postoperative pains are risk factors in the development of chronic pain, although psychological and environmental factors are at work as well. Flagging pain (blue, yellow and red flags) helps to identify risk factors in acute pain that need attention to avoid the transition from acute postoperative pain to acute persistent and then on to chronic pain. This offers a unique opportunity for preventative medicine.

Summary

Recently published literature shows that most patients experience a variety of visual sensations during cataract surgery under local anaesthesia. Most patients (80–100%) retain at least some light perception in the operated eye and many also experience a variety of other visual sensations during cataract surgery under regional ophthalmic anaesthesia (retrobulbar, peribulbar and sub-Tenon's blocks) or topical anaesthesia. The visual sensations experienced include perception of movements, flashes, colours, changes in brightness, or the sight of surgical instruments, the surgeon's hands or fingers, or even the surgeon. These findings are clinically significant because 3–16.2% of patients who had cataract surgery under either regional or topical anaesthesia were frightened by their intraoperative visual experience. Fear and anxiety may cause some patients to become uncooperative during the surgery and may also induce a sympathetic stress response that might cause hypertension, tachycardia with myocardial ischaemia, hyperventilation or an acute panic attack. These effects are especially undesirable as the majority of cataract patients are elderly and have concurrent medical problems. Besides increasing the risk of intraoperative complications, a frightening visual experience may decrease patient satisfaction. Appropriate preoperative counselling has been shown to be effective in reducing the patients' fear. As most patients retain some visual function during cataract surgery under local anaesthesia, anaesthesia providers should be mindful of this phenomenon and offer appropriate preoperative information and counselling to their patients.

Summary

Background and objective: Increased inspired oxygen fractions (FiO2) have significant haemodynamic effects in awake volunteers. We sought to establish whether these effects are also present in anaesthetized patients.

Methods: We prospectively studied 30 ASA I–II patients, 15 in each of a propofol and sevoflurane group. Their haemodynamic responses, awake and anaesthetized, when the FiO2 was changed between 0.3 and 1.0 were measured with a non-invasive transthoracic bio-impedance monitor.

Results: While preoxygenating awake patients in both groups the FiO2 was increased from 0.21 to 1.0. This reduced the mean cardiac index (3.38 ± 0.5 to 3.03 ± 0.5 L min−1 m−2; P < 0.001); reduced the heart rate (HR) (68.1 ± 10.4 to 62.8 ± 9.4 beats per minute (bpm); P < 0.001); and reduced the stroke index (50.4 ± 9.6 to 48.5 ± 8.6; P = 0.02). It increased the systemic vascular resistance index (2060 ± 319 to 2220 ± 382 dyn s−1 cm−5 m−2; P = 0.002); but did not change mean arterial pressure. In the anaesthetized patients, when decreasing the FiO2 from 1.0 to 0.3, mean cardiac index (L min−1 m−2) increased (3.06 ± 0.57 to 3.25 ± 0.56, P = 0.008 for sevoflurane; 2.76 ± 0.46 to 2.89 ± 0.42, P = 0.002 for propofol). The mean HR (bpm) increased (65.1 ± 7.8 to 69.1 ± 7.5, P < 0.001 for sevoflurane; 67.5 ± 11.8 to 72.7 ± 11.6, P = 0.001 for propofol). The mean systemic vascular resistance (dyn s−1 cm−5 m−2) decreased (1883 ± 329 to 1735 ± 388, P = 0.008 for sevoflurane; 2015 ± 369 to 1771 ± 259, P = 0.003 for propofol). Mean arterial pressure (mmHg) decreased (74.8 ± 8.7 to 71.4 ± 8.7, P < 0.001 for sevoflurane; 72.1 ± 8 to 66.5 ± 6.8, P = 0.002 for propofol).

Conclusion: O2 has haemodynamic effects in awake and anaesthetized patients. These effects were of overall similar magnitude for patients anaesthetized with propofol and sevoflurane.

Summary

Background: Ketamine has been claimed to prevent acute opioid tolerance and hyperalgesia following acute exposure to opioids and its use has been proposed to decrease postoperative morphine consumption.

Methods: We conducted a randomized, double-blind, controlled study to evaluate the effect of intravenous (i.v.) ketamine on postoperative pain for 48 h after major ear, nose and throat (ENT) surgery. Thirty-one patients received i.v. ketamine 0.15 mg kg−1 before induction and 2 μg kg−1 min−1 during anaesthesia, and 31 patients were administered placebo in a similar manner. Anaesthesia was standardized with remifentanil and propofol, but without nitrous oxide. Standardized postoperative analgesia included paracetamol, methylprednisolone and morphine administered via a patient controlled analgesia (PCA) device.

Results: Intra-operative remifentanil consumption was not different between the ketamine group (0.25 ± 0.07 μg kg−1 min−1) and the control group (0.22 ± 0.07 μg kg−1 min−1). In the postoperative period, both groups experienced an identical pain course evolution. Cumulative morphine consumption was not significantly different between groups: at 24 h it was 33.3 ± 14.9 with ketamine and 31.9 ± 15.3 mg in controls, at 48 h it was 40.4 ± 20.6 mg with ketamine and 42.5 ± 25.9 mg in controls.

Conclusion: Low-dose ketamine added to a remifentanil-based propofol anaesthesia did not reduce morphine consumption after major ENT surgery.

Summary

Background and objective: The aim of this prospective, randomized, double-blind study was to determine the effects of adding nitrous oxide on sevoflurane requirement for blunting sympathetic responses after surgical incision combined with two different target-controlled concentrations of remifentanil (1 and 3 ng mL−1) in female.

Methods: 102 female patients, aged 20–50 yr, ASA I, undergoing general anaesthesia for elective abdominal surgery were enrolled and randomly allocated to receive sevoflurane anaesthesia alone (Group A, n = 53), or with the addition of 60% nitrous oxide (Group N, n = 49). Patients of both groups were further assigned to receive a target-controlled remifentanil infusion with an effect-site concentration of either 1 ng mL−1 (Group N1, n = 27; Group A1, n = 30), or 3 ng mL−1 (Group N3, n = 22; Group A3, n = 23). Sympathetic responses to surgical incision were determined after a 20-min period of stable end-tidal sevoflurane and target-controlled remifentanil concentrations. Predetermined end-tidal sevoflurane concentrations and minimum alveolar concentration (MAC) for each group were determined using an up-and-down sequential allocation technique.

Results: The MAC of sevoflurane was 3.96% (95% confidence interval, CI95: 3.69–4.23%) in Group A1 and 1.2% (CI95: 0.9–1.3%) in Group N1 (P < 0.01), while in Groups A3 and N3 the MAC of sevoflurane was 0.36% (CI95: 0.24–0.47%) and 0.18% (CI95: 0.1–0.3%), respectively (P < 0.05).

Conclusion: Adding 60% nitrous oxide reduces the MAC of sevoflurane by 70% when using a remifentanil concentration of 1 ng mL−1 and 50% when using a remifentanil concentration of 3 ng mL−1.

Summary

Background and objective: The use of remifentanil requires other analgesics for postoperative pain relief compared to fentanyl in patients undergoing craniotomy. This could possibly reduce the postoperative advantages of this short-acting opioid.

Methods: We compared remifentanil and fentanyl-based anaesthesia in a randomized observer and patient blinded trial on patients, undergoing an elective craniotomy. Twenty patients received anaesthesia using remifentanil with a small dose of piritramide (0.1 mg kg−1) after closure of the dura mater. Twenty patients underwent a fentanyl-based protocol. In both groups, anaesthesia was induced with thiopental and rocuronium, and maintained with 0.6–1 minimum alveolar concentration (MAC) isoflurane in a nitrous oxide/oxygen mixture 2 : 1 and rocuronium. Patients received 1 g of paracetamol rectally postoperatively. A visual analogue scale (VAS) for pain, the Glasgow Coma Score, a modified Aldrete Score, arterial carbon dioxide tension (PaCO2) and piritramide consumption were evaluated every half an hour postoperatively.

Results: No significant differences were found for pain, Aldrete or Glasgow Coma scores or for PaCO2 between the groups when controlled for age, although the pain and Glasgow Coma Scores were consistently higher and PaCO2 lower in the remifentanil group. Furthermore, 13 out of 20 patients in the remifentanil group requested extra piritramide as opposed to 7 out of 20 in the fentanyl group (P = 0.11).

Conclusions: Despite the intraoperative use of piritramide in the remifentanil group, patients experienced more pain postoperatively. A significant influence of age on pain intensity was found. The use of remifentanil with a small dose of piritramide of 0.1 mg kg−1 has no evident advantage over the use of fentanyl considering the postoperative conditions after craniotomy.

Summary

Background and objective: The purpose of intraperitoneal local anaesthetic administration is to block visceral nociceptive conduction and to provide an additional route of analgesia. The present study evaluates the effects of sequential injections of bupivacaine on postoperative pain through a subphrenic catheter.

Methods: In this double-blinded controlled study, patients scheduled for gynaecological laparoscopy were randomly divided into two groups. One group received 20 mL of saline with 1 : 200 000 epinephrine through a subphrenic catheter before the incision closure and at 4-hourly intervals for the first postoperative 20 h. The second group received 20 mL of bupivacaine 0.125% with 1 : 200 000 epinephrine at the same injection times. Postoperative pain scores and consumption of analgesics were compared.

Results: There were no statistical differences in pain scores at rest or incidence of shoulder pain between the two groups, but the patients of the bupivacaine group reported lower pain scores on coughing only in the first hour postoperatively (P = 0.007). Although the patients consumed comparable amounts of metamizole and ondansetron, the number of patients requiring supplemental meperidine and flurbiprofen in the bupivacaine group were significantly lower than in the saline group (P < 0.05).

Conclusions: This study demonstrates that intraperitoneal bupivacaine may reduce pain on coughing in the early postoperative period and the consumption of analgesics postoperatively. The subphrenic catheter technique had no impact upon pain at rest and shoulder-tip pain after gynaecological laparoscopy.

Summary

Background and objective: The aim of this study was to determine the duration of onset and regression time of sensory and motor blocks, the quality of anaesthesia and postoperative analgesia by the addition of dexmedetomidine to local anaesthetic solution in intravenous regional anaesthesia (IVRA).

Methods: Forty patients scheduled for elective hand surgery participated in this prospective randomized double-blind study. The IVRA was achieved using 3 mg kg−1 lidocaine diluted with saline to a total volume of 40 mL in the control group or 1 μg kg−1 of dexmedetomidine +3 mg kg−1 lidocaine diluted with saline to a total volume of 40 mL in the dexmedetomidine group. The onset and regression times for sensory and motor blocks were recorded. Qualities of anaesthesia, intraoperative and postoperative analgesic requirements were noted.

Results: There was no difference between the groups with respect to sensory and motor blocks onset and regression time. The quality of anaesthesia was better in the dexmedetomidine group than the control group and the difference was statistically significant. Intraoperative and postoperative analgesic requirements were greater in the control group than in the dexmedetomidine group.

Conclusions: Addition of dexmedetomidine to local anaesthetic solution in IVRA improved the quality of anaesthesia and decreased analgesic requirements, but had no effect on the sensory and motor blocks onset and regression times.

Summary

Background and objective: This prospective, randomized, double-blind study was conducted to evaluate the onset time and duration of sciatic nerve block produced with 0.5% levobupivacaine, 0.75% levobupivacaine and 0.75% ropivacaine.

Methods: Forty-five healthy patients undergoing hallux valgus repair were randomly allocated to receive sciatic nerve block with levobupivacaine 0.5% (n = 15), levobupivacaine 0.75% (n = 15) or ropivacaine 0.75% 20 mL (n = 15). A femoral nerve block was also performed with mepivacaine 2% 15 mL to cover pain related to the thigh tourniquet. A blinded observer recorded the onset time and duration of sciatic nerve block.

Results: The median (range) onset time was 5 (5–40) min with 0.75% levobupivacaine, 30 (5–60) min with 0.5% levobupivacaine and 20 (5–50) min with 0.75% ropivacaine (P = 0.02 and P = 0.12, respectively). Mean (25–75 percentiles) first request for pain medication occurred after 13 (11–14) h with 0.75% ropivacaine, 18 (15–19) h with 0.75% levobupivacaine and 16 (13–20) h with 0.5% levobupivacaine (P = 0.002 and P = 0.002, respectively). Rescue tramadol after surgery was required by three patients in the 0.75% levobupivacaine group, eight patients in the 0.5% levobupivacaine group and nine patients in the 0.75% ropivacaine group (P = 0.05).

Conclusions: We conclude that 0.75% levobupivacaine provides a shorter onset time than 0.5% levobupivacaine and a longer duration of postoperative analgesia than both 0.5% levobupivacaine and 0.75% ropivacaine with reduced need for rescue analgesia after surgery.

Summary

Background and objective: Adding various opioids to the local anaesthetic solution administrated intrathecally improves the analgesic potency of spinal analgesia. The purpose of this study was to evaluate the efficacy and safety of intrathecal fentanyl 10 μg added to 15 mg hyperbaric ropivacaine in patients undergoing caesarean section under spinal anaesthesia.

Methods: Thirty-seven healthy, full-term parturients were randomly assigned into two groups: Group S (saline group, n = 17) received 15 mg hyperbaric ropivacaine in 2.5 mL + 0.5 mL saline; Group F (fentanyl group, n = 20) received 15 mg hyperbaric ropivacaine in 2.5 mL + 10 μg fentanyl in 0.5 mL, intrathecally. Characteristics of spinal block, intraoperative quality of spinal anaesthesia, time to first feeling of pain (complete analgesia), time to first request of analgesics postoperatively (effective analgesia), side-effects and fetal outcomes were evaluated.

Results: Regression of sensory block to L5 was significantly prolonged in the fentanyl group compared with the saline group (P = 0.001). Time to the first feeling of pain (130.6 ± 15.8 min vs. 154.3 ± 31.1 min; P = 0.008) and the first analgesic requirement (161.2 ± 32.6 min vs. 213.0 ± 29.3 min; P < 0.001) were significantly shorter in the saline group compared with the fentanyl group. Side-effects, umbilical arterial and venous blood gases did not differ between the groups. Apgar scores were similar in both groups and no infants had an Apgar score ≤7 at 5 min.

Conclusions: The addition of fentanyl 10 μg, to hyperbaric ropivacaine 15 mg, for spinal anaesthesia increased the duration of analgesia in the early postoperative period in patients undergoing caesarean delivery.

Summary

Background and objective: An alteration in production of both interleukin-10 (IL-10) and nitric oxide (NO) has been found following surgical/anaesthesia trauma. It is also suggested that IL-10 could be an important factor in regulating NO metabolism during the postoperative period. Furthermore, NO seems to play a crucial role in the anaesthetic state. The purpose of this study was to investigate plasma levels of IL-10 and NO following surgery, any possible correlation between these two variables and whether anaesthesia technique could influence NO and IL-10 circulating concentrations.

Methods: Thirty-two patients scheduled to undergo elective major surgery were enrolled in the study and allocated into two groups to receive two different techniques of anaesthesia, total intravenous (i.v.) anaesthesia (Group I) and inhalational anaesthesia (Group II). Blood samples were drawn before (t0), at the end (t1) of operation and after 24 h (t2). Plasma IL-10 and NO levels were measured by using an enzyme-linked-immunosorbent assay (ELISA) and a total NO assay kit, respectively.

Results: In both patient groups there was a significant decrease of plasma NO levels at the end of surgery (30.35 ± 2.70 mmol L−1 at t0 to 13.76 ± 1.51 mmol L−1 at t1 in Group I, P < 0.0001; 28.23 ± 2.50 mmol L−1 at t0 to 11.38 ± 0.95 mmol L−1 at t1 in Group II, P < 0.0001). This reduction remained at 24 h postoperatively (14.33 ± 1.52 mmol L−1 in Group I, P < 0.0001; 12.52 ± 1.11 mmol L−1 in Group II, P < 0.0001, both vs. t0). There was an increase in IL-10 concentrations (26.35 ± 3.42 pg mL−1 and 75.39 ± 8.33 pg mL−1 at t1 and t2, respectively, vs. 4.93 ± 0.31 pg mL−1 at t0, P = 0.03 and P < 0.0001, respectively, in Group I; 26.18 ± 3.22 pg mL−1 and 69.91 ± 7.33 pg mL−1 at t1 and t2, respectively, vs. 5.50 ± 0.33 pg mL−1 at t0, P = 0.02 and P < 0.0001, respectively, in Group II). No relationship was found between circulating IL-10 and NO.

Conclusions: During the postoperative period, IL-10 overproduction does not correlate with the decrease in systemic NO concentration.

Summary

Background and objective: The intravenous anaesthetic propofol has been reported to exert neuroprotective actions by several mechanisms. This study has been designed to investigate the effects of propofol on intracellular calcium increase in cultured cerebrocortical neurons after exposure to pathological concentrations of N-methyl-d-aspartate (NMDA) mediated by potential direct interactions of propofol with NMDA receptors.

Methods: The effects of propofol (0.1–100 μmol) on intracellular calcium increase induced by 300 μmol NMDA (180 s) were measured in cultured cerebrocortical neurons using the calcium-sensitive fluorochrome calcium green-5N-acetoxymethylester with confocal laser scanning microscopy.

Results: The intraneuronal calcium increase after exposure to 300 μmol NMDA depended on extracellular calcium concentration. Propofol reduced the increase of NMDA receptor-induced intraneuronal calcium concentration dependently with a threshold concentration for a significant effect of 10 μmol. The overall effect was small, since even high concentrations of propofol (100 μmol) diminished intraneuronal calcium rise by only 50%.

Conclusions: The threshold concentration for significant effects of propofol on the NMDA-induced increase of intraneuronal calcium turned out to be in the upper limit of propofol concentrations that are considered to be clinically relevant. However, in the presence of high propofol concentrations, inhibition of NMDA receptor-mediated calcium increase might contribute to neuroprotective effects observed with propofol.