Summary

Background and objective: We tested the hypothesis that disturbances of the visual pathway persist following general anaesthesia, even after normal clinical discharge criteria have been met.

Methods: We performed full-field flash electroretinography in the right eye of 10 unpremedicated ASA I patients who underwent N2O/sevoflurane anaesthesia. Electroretinograms were recorded preoperatively, immediately after discharge from the recovery room and 2 h after discontinuation of sevoflurane. The time at which postanaesthesia discharge score first exceeded 9 was also noted. Data were analysed using paired, one-tailed Student's t-test.

Results: Latency of the b-wave on the photopic electroretinogram was greater at each postoperative time point (30.5 ± 0.9 and 30 ± 1.3 ms), compared to preoperative values (29.2 ± 0.8 ms, P < 0.001 and P = 0.04, respectively). The A–B amplitude of the b-wave was less postoperatively (220.3 ± 52.7 and 210.3 ± 42.7 μV) compared to values before operation (248.1 ± 57.6 μV, P = 0.03 and P = 0.01, respectively). Oscillatory potential latencies were greater at each postoperative time point (21.4 ± 0.5 and 20.8 ± 0.6 ms) compared to before operation (20.4 ± 0.4 ms, P < 0.001 and P = 0.03, respectively). Oscillatory potential amplitudes were less at the first postoperative time point (17.5 ± 6.1 μV), compared to preoperative values (22 ± 6.4 μV, P = 0.04).

Conclusions: Postoperative electroretinogram abnormalities are consistently present in patients who have undergone N2O/sevoflurane anaesthesia. These abnormalities persist beyond the time at which standard clinical discharge criteria have been met.

Summary

Background and objective: Little has been documented about the development of pain after ophthalmic surgery. This study was designed to assess the incidence and severity of postoperative pain following ophthalmic surgery, and to identify key factors independently associated with development of such pain.

Methods: In a prospective, observational cohort study, 500 patients undergoing elective ophthalmic surgery were examined by assessing numerical analogue scales and analgesic requirements.

Results: Depending on anatomical location of surgery, operations could be classified into creating ‘more severe’ or ‘less severe pain’. Patients undergoing posterior segment, corneal and muscle surgery exhibited the highest numerical analogue scale scores (risk ratio 4.5, 95% CI 3.01–6.79, P < 0.0001). Anterior segment surgery, which per se did not create much pain, resulted in significantly more pain when performed under general anaesthesia compared to regional anaesthesia (risk ratio 6.52, 95% CI 2.33–18.2, P < 0.0001). No other factors independently associated with an increased risk of developing serious postoperative pain could be identified.

Conclusions: Patients undergoing certain ophthalmic operations, especially if performed under general anaesthesia, are more likely to experience serious postoperative pain.

Summary

Background and objective: Combined spinal–epidural is an alternative technique to epidural analgesia for labour, but its benefits are not clearly identified.

Methods: A prospective, blinded, randomized study was undertaken involving 113 women attending a university hospital obstetric department. Analgesia was initiated with intrathecal bupivacaine 0.25% 1 mL + sufentanil 5 μg in the combined spinal–epidural group (n = 54), and with bupivacaine 0.125% + epinephrine 2.5 μg mL−1 + sufentanil 7.5 μg in the epidural group (n = 59). In both cases this was followed by patient-controlled epidural analgesia with bupivacaine 0.125% (+sufentanil 0.25 μg mL−1). Duration of labour, quality of analgesia and side-effects were compared between groups.

Results: In the combined spinal–epidural group, the onset of analgesia was faster (5 vs. 15 min, P < 0.001), the consumption of bupivacaine was lower (7.5 vs. 11.3 mg h−1, P = 0.003) and there was less unilateral analgesia (14.8% vs. 40.7%, P = 0.002) than in the epidural group. The characteristics of labour were similar in both groups. However, in the combined spinal–epidural group, there was a higher incidence of posterior presentation (25.9% vs. 10%, P = 0.03), pruritus (P < 0.001), hypotension (P = 0.002), somnolence (P = 0.01), nausea (P = 0.02) and one case of meningitis.

Conclusions: The combined spinal–epidural technique provided more effective analgesia during labour than epidural analgesia alone but offered no other advantage. It induced more adverse effects and this should be considered before routinely using the combined spinal–epidural technique.

Summary

Background and objective: The prognosis of diabetic patients after surgery remains controversial. Some suggest that the rates of death and complications today are almost identical in diabetic and non-diabetic patients within hospital stay or for 30 days postoperatively, whereas others suggest that diabetes still constitutes a major risk factor for both short-term (≤30 days) and long-term (>30 days) patients especially after major cardiac surgery. We examined the long-term postoperative mortality of diabetic patients undergoing major non-cardiac surgery to identify possible perioperative risk factors.

Methods: Data from 179 consecutive diabetic patients, who underwent major non-cardiac surgery at Herlev Hospital, Denmark, during a 12 month period, have been retrospectively analysed. Data were obtained from patient records and from The Danish National Health Register. The main outcome measure was postoperative mortality. Patients were followed for a maximum of 18 months.

Results: The median postoperative observation period was 10 months (range 0–18 months). Overall postoperative mortality was 24% (95% confidence interval (CI) 17–31%). One third of the fatalities occurred during the first 30 days. Ischaemic heart disease diagnosed before the operation was associated with an overall postoperative mortality of 44% (95% CI 29–58%), which was significantly (P < 0.03) higher than in diabetic patients without known cardiovascular disease. The major causes of death in 18 out of 39 (46%) patients were diseases of the cardiovascular system.

Conclusions: Diabetic patients undergoing major non-cardiac surgery seem to have a high mortality, often because of cardiovascular death. Future strategies should focus on implementing cardio-protective treatment during the perioperative period.

Summary

Background and objective: There are anecdotal reports of dysphoria occurring in patients on the first day after anaesthesia with remifentanil. This study was performed to investigate this allegation and to find a possible relationship to postoperative shivering or to nausea and vomiting.

Methods: Patients undergoing otorhinolaryngeal surgery took part in a prospective, randomized, double-blind study comparing total intravenous anaesthesia with propofol (2 mg kg−1 bolus injection then 100 μg kg−1 min−1) and remifentanil (1 μg kg−1 bolus then 0.1–0.5 μg kg−1 min−1) or alfentanil (30 μg kg−1 bolus then 0.16–0.83 μg kg−1 min−1). The patients were carefully insulated and actively warmed by convective heating and rectal temperature was monitored continuously. Postoperative shivering was graded on a three-point scale, and the cumulative incidence of nausea and vomiting were registered at 24 h after surgery. Pre- and postoperative mood was measured with the von Zerssen mood scale (Befindlichkeits-Skala) and changes tested for significance. High scores reflect discontent and dysphoria.

Results: The data of 98 patients (49 in each group, ASA I–II, age 42 ± 13 yr, anaesthesia time 141 ± 60 min; mean ± SD; intergroup P values >0.1) were evaluated. Core temperature did not change perioperatively (before 36.6 ± 0.2°C; after 36.8 ± 0.3°C, inter- and intragroup P > 0.1). The incidence of nausea was the same in each group; vomiting occurred with equal frequency (6/49 vs. 7/49). Shivering was significantly more frequent after remifentanil (41% vs. 10%, P < 0.001). The patients' mood remained stable after remifentanil but worsened after alfentanil (von Zerssen score from 9.3 ± 2.5 to 13.9 ± 3.6; mean ±95% confidence intervals; P < 0.01).

Discussion: Postoperative shivering was more frequent after remifentanil but was unrelated to intraoperative heat loss. Contrary to preliminary informal observations, there was no evidence that remifentanil caused post-anaesthetic dysphoria on the day one after surgery.

Summary

Background and objective: To compare the accuracy of prognoses made by intensive care physicians with the performance of two indicators, the original Simplified Acute Physiology Score (SAPS) II and a modified version optimized to the patient sample.

Methods: Data from 412 patients consecutively admitted to intensive care units of Göttingen University Hospital, Germany, were collected according to the original score criteria. Information necessary for the computation of SAPS II and the vital status on hospital discharge was recorded. To customize the original SAPS II in our cohort, the database was randomly divided into two subgroups. Logistic regression analysis with physiological values as explanatory variables was used. A bootstrap procedure completed the process. Furthermore, physicians were asked to indicate their prognostic judgement concerning the patients’ hospital mortality.

Results: Discrimination analysis showed the following areas under receiver operating characteristic curves: physicians’ prognoses 0.84 (confidence interval (CI): 0.79–89), SAPS II 0.75 (CI: 0.69–0.80) and customized SAPS 0.72 (CI: 0.66–0.78). The physician's forecast was significantly better, while the customized and the original SAPS were not substantially different as regards their accuracy.

Conclusions: Prognoses made by physicians are superior to objective models. This may result from more extensive knowledge and other kinds of information available to clinicians. A clinician's action also depends on his/her prognosis at the beginning of the treatment, giving raise to a possible correlation between medical outcome and the clinician's prognosis. Our findings indicate that physicians do not limit their prognosis to the objective factors at their disposal, but indicate that they base their decisions on experience and individual observations.

Summary

Background and objective: Isoflurane has been shown experimentally to protect the myocardium against infarction but the clinical relevance of these findings is not yet well established. We therefore evaluated the effects of isoflurane administration before cardiopulmonary bypass (CPB) on postoperative cardiac troponin I (cTnI) release and clinical outcome in a large group of adult patients scheduled for cardiac surgery.

Methods: Three hundred and fifty-nine consecutive patients were included prospectively in an open observational study and divided into two groups according to whether or not isoflurane was administered before CPB. Postoperative cTnI release, in-hospital mortality, time to discharge from hospital, time to extubation and non-fatal postoperative cardiac events (number of internal cardioversions, need for inotropic support, ischaemic events, dysrhythmias and/or conduction abnormalities) were recorded.

Results: Two hundred and twenty-one (62%) patients did not receive isoflurane and 138 (38%) received isoflurane (1.3% [1.0–1.8%] minimum alveolar concentration over 22 [15–33] min). Postoperative cTnI release was not significantly different between the control and isoflurane groups (5.9 [1.0–336.8] vs. 6.0 [1.5–392.0] ng mL−1, P = 0.88). No significant differences were found in non-fatal cardiac events (63% vs. 57%, P = 0.22) and in-hospital mortality (1.8% vs. 1.4%, P = 0.79) between the control and isoflurane groups.

Conclusions: No significant effect was observed on postoperative cTnI release and in-hospital outcome when isoflurane was added to standardized intravenous anaesthesia before CPB in adult patients undergoing cardiac surgery.

Summary

Background and objective: Continuous spinal analgesia (CSA) offers considerable pain relief, and has been used in various procedures such as for surgery and cancer pain control. In Japan, portable and disposable infusion kits are increasingly employed for continuous epidural analgesia and CSA. In CSA, the use of a microcatheter is expected to reduce the incidence of spinal headache previously encountered with larger catheters. However, the flow rate of disposable infusion kits is reduced when used in conjunction with a microcatheter.

Methods: This study aimed to investigate the influence of catheter length on the flow rate of two different devices: 20- or 91-cm 28-G microcatheters connected to balloon- or syringe-type infusion pumps were examined (50 mL, 1 mL h−1). There were four groups each of 10 experiments: Group A: balloon-type infuser, 91 cm catheter; Group B: balloon-type infuser, 20 cm catheter; Group C: syringe-type infuser, 91 cm catheter; Group D: syringe-type infuser, 20 cm catheter.

Results: The mean flow rate in Group A was significantly less than that in Group B and the mean flow rate in Group C was significantly less than Group D (P < 0.05).

Conclusion: These results indicated that the use of a shorter microcatheter achieves a better flow rate during CSA.

Summary

Background and objective: The aim of this study was to test the efficacy of positive end-expiratory pressure (PEEP) to the dependent lung during one-lung ventilation, taking into consideration underlying lung function in order to select responders to PEEP.

Methods: Forty-six patients undergoing open-chest thoracic surgical procedures were studied in an operating room of a university hospital. Patients were randomized to receive zero end-expiratory pressure (ZEEP) or 10 cmH2O of PEEP to the dependent lung during one-lung ventilation in lateral decubitus. The patients were stratified according to preoperative forced expiratory volume in 1 s (FEV1) as an indicator of lung function (below or above 72%). Oxygenation was measured in the supine position, in the lateral decubitus with an open chest, and after 20 min of ZEEP or PEEP. The respiratory system pressure–volume curve of the dependent hemithorax was measured in supine and open-chest lateral decubitus positions with a super-syringe.

Results: Application of 10 cmH2O of PEEP resulted in a significant increase in PaO2 (P < 0.05). This did not occur in ZEEP group, considered as a time matched control. PEEP improved oxygenation only in patients with high FEV1 (from 11.6 ± 4.8 to 15.3 ± 7.1 kPa, P < 0.05). There was no significant change in the low FEV1 group. Dependent hemithorax compliance decreased in lateral decubitus, more in patients with high FEV1 (P < 0.05). PEEP improved compliance to a greater extent in patients with high FEV1 (from 33.6 ± 3.6 to 48.4 ± 3.9 mL cmH2O−1, P < 0.05).

Conclusions: During one-lung ventilation in lateral decubitus, PEEP applied to the dependent lung significantly improves oxygenation and respiratory mechanics in patients with rather normal lungs as assessed by high FEV1.

Summary

Background and objective: The anaesthesiologist's preoperative interview with the patient is important in preparing the patient for surgery. Its potential protective influence on adverse side-effects from anaesthesia and convalescence is rarely investigated within the context of other perioperative factors. Structural equation modelling allows detection and quantification of all causal relationships and mediator effects in multivariate models. Therefore, this method is presented as a tool and applied to discover the influence of the preoperative interview within socio-demographic variables and duration of surgery on complaints and recovery after anaesthesia.

Methods: The influence of individual satisfaction with the anaesthesiologist's preoperative interview on postoperative events such as nausea/vomiting, difficulties in recovering from anaesthesia, experience of postoperative pain, physical discomfort and satisfaction with convalescence expressed by the patient was analysed by means of structural equation modelling. The variables gender, age and duration of surgery were also included as predictors in the analyses. The model in the total sample of 710 patients was then analysed for structural differences between groups treated either with propofol (n = 204) or with isoflurane + nitrous oxide (n = 267) for maintenance of anaesthesia.

Results: The model revealed that the anaesthesiologist's preoperative interview in combination with associated mediating side-effects explains 45% of the variance of ‘feeling physical discomfort’ and 18% of the variance of ‘satisfaction with convalescence’. The same model could be fitted in the propofol and the isoflurane + nitrous oxide group. Moreover, the structure and the strength of causal relations between variables were identical in the two groups.

Conclusions: The anaesthesiologist's efforts to improve the interview with the patient by more reassuring and proper information will result in less side-effects from anaesthesia and better recovery from surgery. It could be demonstrated that structural equation modelling is a powerful tool for detection of causal relationships and mediator effects in perioperative medicine.

Summary

Background and objective: This prospective observational study analyses cardiovascular changes in adult patients with acute respiratory distress syndrome (ARDS) during transition from pressure-controlled ventilation to high-frequency oscillatory ventilation (HFOV), using transoesophageal echocardiography (TOE) and invasive haemodynamic monitoring.

Methods: Nine patients (median age 65 years; range 42–70) with ARDS were studied. HFOV was started and maintained with an adjusted mean airway pressure of 5 cmH2O above the last measured mean airway pressure during pressure-controlled ventilation. Haemodynamic and TOE measurements were performed in end-expiration during baseline pressure-controlled ventilation, and again 5 and 30 min after the start of during uninterrupted HFOV.

Results: Right atrial pressure increased immediately (P = 0.004). After 30 min, pulmonary arterial occlusion pressure increased (P = 0.008), cardiac index decreased (P = 0.01), stroke volume index decreased (P = 0.02) and both left ventricular end-diastolic and end-systolic area indices decreased (P = 0.02). Fractional area change, left ventricular end-systolic wall stress, heart rate, mean arterial pressure and mean pulmonary artery pressure remained unchanged.

Conclusions: Transition to HFOV at a mean airway pressure of 5 cmH2O above that during pressure-controlled ventilation induced significant, but clinically minor, haemodynamic effects, which are most probably due to airway pressure-related preload reduction.

Summary

Background and objective: The kneeling prone position is often used for low back surgery in order to decrease intraoperative bleeding and increase the surgical exposure of the vertebral canal. The aim of this study was to assess effects of the kneeling prone position on respiratory gas exchange focusing on oxygen consumption and early changes in oxygenation.

Methods: Thirty ASA I–II patients scheduled for low back surgery in the kneeling prone position were studied. Anaesthesia was maintained with isoflurane, 1.2% end-tidal concentration. Respiratory gas exchange was measured with indirect calorimetry.

Results: When the patients were turned into the kneeling prone position their oxygenation was immediately improved – measured by arterial oxygen tension and arterial oxygen saturation. The oxygen uptake rate did not change from a baseline supine level of 76 mL min−1 m−2, but the carbon dioxide excretion rate decreased from a baseline supine value of 71 mL min−1 m−2 to 66 mL min−1 m−2 at 5 and 10 min after the kneeling prone position was adopted. Alveolar ventilation decreased in the kneeling prone position.

Conclusions: The present study demonstrates that the kneeling prone position improves oxygenation and that the mechanisms involved are fast in onset. Furthermore, the prone position does not change oxygen consumption although alveolar ventilation is significantly reduced. The changes in alveolar ventilation could possibly be the result of circulatory changes caused by the prone position, but further studies are needed to clarify that hypothesis.

Summary

Background and objective:Only regular training of anaesthetic personnel ensures safe and reliable application of cricoid pressure during rapid sequence induction of anaesthesia. Previously described training devices are either complicated, too expensive and usually unavailable, or they are very simple and do not correctly simulate the process of applying cricoid force. We designed and tested a cricoid pressure trainer with real-time display of applied force. The device is easy to assemble at relatively little cost with material widely available. It allows effective biofeedback training of the force required during the Sellick manoeuvre and can be used for routine staff assessment.

Methods:Thirty-six anaesthesia assistants were assessed for their correct application of cricoid pressure. Previous training in, and knowledge of, applying cricoid pressure was first evaluated by a questionnaire. We designed a model for testing the application of cricoid force. Pre-training cricoid forces were obtained by asking the subjects to apply ‘awake’ (10 N = 1.020 kg) and ‘asleep’ (30 N = 3.060 kg) cricoid pressure on our model while blinded to the actual pressure produced. The volunteer was then trained to apply correct pressure employing real-time biofeedback. Post-training values were later determined with the subject again blinded to the actual applied pressure.

Results:Post-training performance showed significant improvement in the application of the correct cricoid force (P<0.0005). Only 8% (3/36) of subjects applied incorrect ‘awake’ cricoid pressure after training vs. 56% (20/36) before training. All participants applied correct ‘asleep’ cricoid pressure after training vs. 72% (26/36) failing before training.

Conclusions:Our biofeedback cricoid pressure trainer is effective in the assessment and training of correct cricoid pressure application by anaesthetic personnel.

Summary

Background and objective: The randomized, patient- and observer-blinded study was performed in 120 patients undergoing ear, nose and throat surgery to test the hypothesis that intravenous anaesthesia with propofol–remifentanil when compared with a balanced anaesthesia technique using isoflurane–alfentanil improves the speed of recovery, minimizes postoperative side-effects and, thus, leads to an improved quality of recovery without increasing total costs.

Methods: The total costs for each anaesthesia technique were calculated considering drug acquisition costs, personnel costs for the additional time spent in the operating room and the postanaesthesia care unit until fast-tracking eligibility, and the costs to treat the side-effects during and after operation.

Results: The times from the end of surgery to tracheal extubation and the time until leaving the operating room were not different between the two groups. However, more patients receiving intravenous anaesthesia (80 versus 49%) were eligible for fast tracking and thus could bypass the recovery room. This was associated with an average cost saving of €6.00 per patient. However, intravenous anaesthesia was associated with higher total costs (€89 versus €78) mainly because of higher acquisition costs of the anaesthetics (€34.60 versus €16.50). There was no difference in the quality of recovery as measured by a Quality of Recovery score and patient satisfaction between the two groups.

Conclusions: The higher acquisition costs of the intravenous anaesthetics propofol and remifentanil cannot be compensated for by improved speed of recovery. This anaesthesia technique is more cost intensive than balanced anaesthesia using isoflurane and alfentanil.

Summary

Background and objective: Sevoflurane and propofol reduce the extent of necrosis and improve neurological outcome in rodent models of cerebral ischaemia and reperfusion. However, the effects of these anaesthetics on programmed cell death (apoptosis) are unclear. The present study investigates whether sevoflurane and propofol affect the expression of apoptosis-regulating proteins after cerebral ischaemia in rats.

Methods: Thirty-two fasted male Sprague–Dawley rats were tracheally intubated and the lungs were ventilated (isoflurane and N2O/O2 anaesthesia). After surgical preparation, the animals were randomly assigned to one of the following groups: control (n = 8): fentanyl intravenous (10 μg kg−1 bolus and 25 μg kg−1 h−1 infusion) with N2O/O2; sevoflurane (n = 8): 2.0% sevoflurane (end-tidal concentration) and O2/air; propofol (n = 8): 0.8–1.0 mg kg−1 min−1 propofol intravenous and O2/air; sham-operated (n = 8): 25 μg kg−1 h−1 fentanyl intravenous and N2O/O2, no cerebral ischaemia. Ischaemia (30 min) was induced by unilateral common carotid artery occlusion plus haemorrhagic hypotension to a mean arterial pressure of 30–35 mmHg. Four hours after cerebral ischaemia the brains were removed and the expression of apoptosis-regulating proteins (Bax, Bcl-2, p53, Mdm-2) was determined using immunofluorescence and Western-blot analyses.

Results: The expression of the pro-apoptotic protein Bax was greater in control animals than in sevoflurane or propofol anaesthetized rats and than in sham-operated animals. The concentrations of Bcl-2, p53 and Mdm-2 were not changed 4 h after cerebral ischaemia.

Conclusions: In addition to the anti-necrotic effects of sevoflurane and propofol, these anaesthetics also reduce the concentration of the apoptosis-inducing protein Bax as early as 4 h after ischaemia.

Summary

Background and objective: Intrathecal ketamine as the sole anaesthetic agent has demonstrated a lack of cardiovascular depression that should be of advantage in an elderly population. S(+) ketamine has three-times the analgesic potency of R(−) ketamine and its antinociceptive effects after intrathecal administration in rats are known. We decided to evaluate the effects of intrathecal S(+) ketamine added to a small dose of spinal bupivacaine in elderly patients undergoing transurethral prostate surgery.

Methods: Forty males over 60 yr old, scheduled for transurethral prostate resection under spinal anaesthesia, were studied in a prospective, double-blinded, randomized way. Patients were allocated to receive either bupivacaine 10 mg or bupivacaine 7.5 mg combined with S(+) ketamine 0.1 mg kg−1. Spinal block onset time, maximum sensory level, duration of blockade, haemodynamic variables, postoperative analgesic requirements and adverse events were recorded.

Results: Onset times of motor and sensory block were shorter in the bupivacaine plus S(+) ketamine group. Incomplete motor block of the lower extremities was seen in 80% of the patients in bupivacaine plus S(+) ketamine group. Duration of complete motor block and spinal analgesia was shorter in the bupivacaine plus S(+) ketamine group. There was no significant difference in arterial pressure. Heart rate decreased after spinal anaesthesia in the bupivacaine plus S(+) ketamine group and was significantly lower until the end of anaesthesia. The incidence of adverse effects was not different between groups.

Conclusions: Intrathecal S(+) ketamine administered with a low dose of bupivacaine provides shorter motor and sensory block onset time, shorter duration of action and less motor blockade in elderly males.

Summary

Background and objective: The quality of combined spinal–epidural anaesthesia mainly depends on accurate identification of the epidural space. The real-time ultrasound control of the procedure for puncture was therefore evaluated.

Methods: Thirty parturients scheduled for Caesarean section were randomized to three equal groups. Ten control patients received conventional combined spinal–epidural anaesthesia. Ten of the remaining patients received ultrasonic scans by an offline scan technique, and 10 received online imaging of the lumbar region during epidural puncture. The epidural space was identified and needle advancement was surveyed through the interspinal and flaval ligaments. The number of attempts to advance the needle to achieve a successful puncture was measured and compared, as well as the number of vertebral interspaces punctured before successful entry into the epidural space.

Results: There was no difference between patient characteristics in the three groups. The visualization of the epidural structures and of the needle manipulations was very effective. In the ultrasound group, the reduction in the number of attempts at puncture was significant (P < 0.036). The number of interspaces necessary for puncture was reduced (P < 0.036) in the ultrasound online group compared with controls. The number of spinal needle manipulations was significantly reduced (P < 0.036).

Conclusions: Real-time ultrasonic scanning of the lumbar spine is an easy procedure. It provides an accurate reading of the location of the needle tip and facilitates the performance of combined spinal–epidural anaesthesia.

Summary

Background and objective: Unplanned hospital admission is a measure of quality of care in the setting of day-case surgery. We set out to identify the incidence and causes of unplanned hospital admission in a paediatric day-case unit.

Methods: A retrospective survey to determine the incidence and causes of unplanned hospital admissions in children undergoing day-case surgery. The survey covered the period from January 1996 until December 1999 inclusive in a university affiliated children’s hospital. This hospital is the second largest paediatric referral centre in Ireland with total admissions across all specialities during the study period of 42 738.

Results: During the study period 10 772 children underwent day-case surgery, of whom 242 (2.2%) experienced unplanned hospital admission. The reasons for admission were surgical 146 (54%), anaesthetic 44 (16%), social 38 (14%), medical 31 (11%) and unclassified 10 (4%). Pain, surgical complications and/or further management, admission for observation, extensive surgery and oozing were the commonest surgical reasons. Postoperative nausea and vomiting, anaesthetic-related complication and somnolence were the commonest anaesthetic causes responsible for admission. Surgery performed after 15:00 h was an important factor associated with admission for social reasons. Orthopaedic surgery accounted for the largest absolute number of unplanned admissions with 61 (25%), followed by urology with 46 (19%) and general surgery with 46 (19%). However, measured as percentage of caseload, urology had the highest proportion of unplanned hospital admissions.

Conclusion: This study demonstrated that the incidence and causes of unplanned hospital admission following day-case surgery in children are similar to those for adults.

Summary

Background and objective: We hypothesized that remifentanil–propofol cardiac anaesthesia, plus administration of pirinitramide (piritramide) upon cessation of the remifentanil infusion, would be associated with a shorter time to tracheal extubation than alfentanil–propofol anaesthesia, without the occurrence of major haemodynamic instability.

Methods: Haemodynamic stability and recovery characteristics of two remifentanil infusion regimens (0.5 μg kg−1 min−1; 0.25 μg kg−1 min−1) were therefore compared with an alfentanil infusion regimen (1 μg kg−1 min−1), in combination with target-controlled infusion of propofol, in a randomized blinded trial in 75 coronary artery surgery patients.

Results: Pirinitramide provided good postoperative analgesia without prolonging extubation times: median extubation time in minutes after stopping the opioid-sedative drugs was 300 in the higher-dose remifentanil group and 270 in the lower-dose remifentanil group and alfentanil group (P = 0.606). Significant time-by-treatment interactions were seen for systolic arterial pressure (P = 0.015), mean arterial pressure (P = 0.009) and diastolic arterial pressure (P = 0.006). No significant interaction (P = 0.489) and no constant treatment effect were seen for heart rate (P = 0.288). Time effects were highly significant (P < 0.0001) for all haemodynamic variables. Heart rate remained stable in all groups. In the higher-dose remifentanil group, blood pressure was significantly different and lower during surgery and in this group less bolus doses of the opioid-sedative drugs (P = 0.015) had to be given.

Conclusion: The higher-dose remifentanil infusion provided superior suppression of haemodynamic responses to noxious stimuli with better haemodynamic stability.

Summary

Background and objective: In previous studies we have demonstrated that it is possible and safe to identify the lumbar epidural space by an acoustic and visible signal. The use of an experimental set-up constructed for this purpose, the acoustic puncture assist device, the lumbar epidural puncture procedure became both audible and visible. In the present study we have extended the use of the device to localize the thoracic epidural space. We have also evaluated whether the device can be used as a practical tool to confirm correct catheter placement.

Methods: In 100 consecutive patients a prototype of the acoustic puncture assist device was connected to the epidural needle in order to localize the epidural space. The device translates the pressure encountered by the needle tip into a corresponding acoustic and visible signal and enables the anaesthesiologist to detect the epidural space by means of the acoustic signal. After catheter insertion, local anaesthetic was administered. Subsequently the epidural block was tested. In 10 patients the device was also connected to the epidural catheter after its insertion into the epidural space.

Results: In all 100 patients included in the study the epidural space was successfully located by means of the acoustic signal. The only recorded complication was intravascular catheter placement in two patients.

Conclusions: It is possible to localize the thoracic epidural space guided by an acoustic signal. The method was shown to be safe, reliable and simple. Potential implications of this technique include better needle control, improved monitoring for training purposes and for clinical documentation of the thoracic epidural puncture as well as identifying correct catheter placement.