Summary

Objective: To evaluate the effect of postoperative pain control in cardiac surgical patients on morbidity, mortality and other outcome measures. Background: New approaches in pain control have been introduced over the past decade. The impact of these interventions, either alone or in combination, on perioperative outcome was evaluated in cardiac surgical patients. Methods: We searched Medline for the period of 1980 to the present using the key terms analgesics, opioid, non-steroidal anti-inflammatory drugs, cardiac surgery, regional analgesia, spinal, epidural, fast-track cardiac anaesthesia, fast-track cardiac surgery, myocardial ischaemia, myocardial infarction, postoperative care, accelerated care programmes, postoperative complications, and we examined and discussed the articles that were identified to be included in this review. Results: Pain management in cardiac surgery is becoming more important with the establishment of minimally invasive direct coronary artery bypass surgery and fast-track management of conventional cardiac surgery patients. Advances have been made in this area and encompass specific techniques, such as central neuraxial blockade or selective nerve blocks, and drugs (opioids, sedative-hypnotics and non-steroidal anti-inflammatory drugs). Ideally, these therapies provide not only patient comfort but also mitigate untoward cardiovascular responses, pulmonary responses, and other inflammatory and secondary sympathetic responses. The introduction of these newer approaches to perioperative care has reduced morbidity, but not mortality, in cardiac surgical patients. Conclusions: Understanding perioperative pathophysiology and implementation of care regimes to reduce the stress of cardiac surgery, will continue to accelerate rehabilitation associated with decreased hospitalization and increased satisfaction and safety after discharge. Reorganization of the perioperative team (anaesthesiologists, surgeons, nurses and physical therapists) will be essential to achieve successful fast-track cardiac surgical programmes. Developments and improvements of multimodal interventions within the context of ‘fast-track’ cardiac surgery programmes represents the major challenge for the medical professionals working to achieve a ‘pain and risk free’ perioperative course.

Summary

Background and objectives: Supplemental oxygen is commonly given via nasal cannulae in spontaneously breathing patients. Our modified nasal cannula with a clamp between the nasal prongs can provide O2 via one nostril and CO2 can be sampled through the other one. We have studied whether this cannula can provide oxygenation similar to a standard cannula without affecting end-tidal CO2 monitoring. Methods: Eighty-six patients were studied during spinal anaesthesia and sedation. In 15 patients, arterial blood was sampled while O2 was delivered at flow rates of 0, 2 and 4L min−1, with or without clamping between the prongs of our modified nasal cannula. In the remaining 71 patients, arterial O2 was measured while using our modified nasal cannula with the clamp applied. End-tidal CO2 was recorded on a capnograph and the correlation between end-tidal and arterial values with our modified nasal cannula was investigated. Results: No end-tidal CO2 waveforms were found with oxygen flow greater than 2L min−1 without clamping between the prongs. With clamping there was a significant correlation (r = 0.83) between arterial and end-tidal CO2. A Bland–Altman analysis revealed a bias of 0.49 kPa with precision of ±0.76 kPa. Arterial oxygenation was not affected by our modified nasal prongs with clamp as compared to the standard cannula. Conclusion: Our modified nasal cannula can provide continuous monitoring of end-tidal CO2 without affecting oxygen delivery in sedated, spontaneously breathing patients.

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.

Background and objective: Although combined spinal and epidural anaesthesia is efficient and easy to perform, the technique can be a double-edged sword having the potential risk that an increased flux of drugs across the meninges through the hole made in it may lead to severe adverse effects. The aim was to compare the incidence of adverse events when an epidural injection of morphine was given after combined spinal and epidural anaesthesia or after epidural anaesthesia.

Methods: Fifteen patients had an epidural catheter inserted at the L2–3 interspace, and then a spinal block administered via the L3–4 interspace. Another 15 patients only had an epidural catheter inserted. After the onset of spinal or epidural anaesthesia had been confirmed, morphine 2 mg was injected into the epidural space, and a continuous epidural infusion of morphine was started. At the end of the operation and at 4, 8 and 12 h after the administration of epidural morphine and on the next day, the following variables were examined: blood pressure, heart rate, respiratory rate, arterial blood-gas analysis, visual analogue scale pain scores, nausea/ vomiting scores, and pruritus scores.

Results: In the study population, the epidural injection of morphine was not associated with a significantly higher incidence of adverse events when given after spinal anaesthesia than after epidural anaesthesia.

Conclusions: The adverse effects associated with epidural morphine given after spinal anaesthesia did not increase significantly when a 27-G Whitacre needle was used. Thus, the morphine flux through the meningeal hole into the cerebrospinal fluid was trivial.

Background and objective: The α2-adrenoceptor agonist clonidine has potent central antinociceptive properties. The study was designed to investigate the effects of the combined subarachnoid administration of clonidine and prilocaine on spinal block and postoperative analgesia for the transurethral resection of tumours in the urinary bladder.

Methods: The controlled, prospective, double-blind study enrolled 40 patients scheduled for elective transurethral resection of bladder tumours under spinal anaesthesia with prilocaine. Patients were randomly assigned to receive an intrathecal injection of prilocaine 75 mg alone (control group) or in combination with clonidine 75 µg. We assessed haemodynamic changes (non-invasive arterial pressure, heart rate), pulse oximetry, the upper level of block, the onset and duration of sensory and motor block, postoperative analgesia and any adverse effects.

Results: There were no statistically significant differences in demographic data, heart rate, onset time or the levels of sensory or motor block. Analgesia lasted significantly longer in the clonidine group (498.4 ± 226.9 versus 187.2 ± 103.1 min; P < 0.05). The duration of motor block was longer in the clonidine group (165.5 ± 30.6 min) than in the control group (139.7 ± 40.4 min; P < 0.05) and the duration of sensory block was also longer in the clonidine group (157.3 ± 24.5 min) than in the control group (137.2 ± 31.2 min; P < 0.05). Fewer patients in the recovery room needed metamizol (dipyrone) in the clonidine group (5%) than in the control group (50%). Arterial pressure decreased significantly in the clonidine group 75-135 min after the block.

Conclusions: The addition of clonidine 75 µg to prilocaine 75 mg for subarachnoid anaesthesia increased the duration of sensory and motor block and reduced the need for additional postoperative analgesics by providing excellent analgesia for about 8 h during recovery from transurethral resection of bladder tumours.

Background and objective Little information exists on cerebrospinal fluid pressures in non-labouring pregnant women. The technique of spinal anaesthesia means that inadequate levels of sensory blockade are difficult to manage. If the block is found to be inadequate after surgery has commenced, then conversion to general anaesthesia may be the only option. It is important that any manoeuvre altering the spread of local anaesthetic is considered at the time of subarachnoid injection. This study investigates the feasibility of using a fine bore needle with an electronic transducer to measure cerebrospinal fluid pressure and whether this was affected by either of the two lateral positions. We also sought to measure whether the right or left lateral position affected subsequent block height and requirements for supplementary analgesia.

Methods Two groups of 17 women presenting for elective Caesarean section were allocated to receive spinal anaesthesia in either the right or left lateral position. Cerebrospinal fluid pressure was measured by use of a rapid response electronic transducer connected to the hub of the spinal needle. Anaesthetic levels to cold sensation were assessed at 5, 10 and 15 min after injection of hyperbaric bupivacaine. During surgery, requirements for supplementary analgesia were recorded.

Results There was no significant difference in cerebrospinal fluid pressure between the two positions. While there was a trend towards more rapid analgesia in the right lateral group, this did not reach statistical significance. Two blocks performed in the left lateral group were inadequate for surgery but this was not statistically significant. Overall, 39% of women required supplementary analgesia during surgery. The incidence was not significantly different between the two groups.

Conclusion Adoption of either the right or left lateral position for placement of spinal anaesthesia results in no difference in cerebrospinal fluid pressure or quality of block. The technique described gives a reliable and reproducible method of cerebrospinal fluid pressure measurement.

Background and objective The effect of anaesthesia induced by intrathecal injection of 6.3% MgS04 or 4% lidocaine on intracellular electrolyte homeostasis in spinal cord neurones of a rat model was investigated. Methods Intracellular Ca2+, Mg2+, Na+ and K+ concentrations were determined at different times after intrathecal administration of NaCI (saline, a control group), MgS04 or lidocaine.

Results In both thoracic and lumbar spinal cord segments, Ca2+ concentrations rose significantly 30min and 2 h after 6.3% MgSO4 injection, and after 24 h were still significantly increased compared with the values obtained from the control group which were subjected to sham ‘anaesthesia’ by saline injection (172,121 and 108ngmg−1 protein vs. control 23ngmg−1 protein, respectively, in the thoracic segment and 222, 229 and 176ngmg−1 protein vs. control 43ngmg−1 protein, respectively, in the lumbar segment). Lidocaine injection also produced a significant increase in intracellular Ca2+ in the thoracic and lumbar spinal cord segments (69, 64 and 53ngmg−1 protein vs. control 33.4 ngmg−1 protein and 26, 94 and 46ngmg−1 protein vs. 23ngmg−1 protein respectively). Only a modest rise in intracellular Mg2+ was observed after intrathecal MgS04 or lidocaine injection (27ngmg−1 protein vs. 23ngmg−1 protein). Na+ and K+ concentrations decreased 24 h after MgS04and 1h after lidocaine injection.

Conclusion Intrathecal anaesthesia by MgS04 or lidocaine alters intracellular electrolyte homeostasis in spinal cord neurones of experimental rats. A possible common mechanism of action via Ca2+ ion channels is discussed.