Summary

Background and objective: Postoperative nausea and vomiting (PONV) after ophthalmic surgery under general anaesthesia remains a complex and perturbing complication associated with several factors. Little information is available regarding the risk factors for nausea and vomiting after vitrectomy in adults. In this study, we evaluated the potential risk factors for PONV after vitrectomy in adult patients. Methods: Univariate and multivariate analyses of clinical factors associated with PONV were undertaken in a retrospective case–control series of 247 adult patients undergoing vitrectomy under general anaesthesia. We examined PONV for the first 48 h. Factors examined were age, body mass index (BMI), smoking status, H2-blocker as premedication, type of general anaesthesia (sevoflurane and fentanyl or total intravenous (i.v.) anaesthesia with propofol and fentanyl), duration of surgery, and intraoperative fentanyl dose. Results: Fifty-nine patients (24%) reported one or more episodes of PONV during the study period. Female gender (P < 0.01), lower BMI (P < 0.01) and general anaesthesia with inhalational anaesthetics (P < 0.01) were significantly related to nausea during the first 2 h postoperatively. Female gender (P < 0.01) was significantly related to nausea and vomiting throughout the study period. Other factors, including smoking status, did not alter the risk for nausea and/or vomiting. Conclusions: We conclude that female gender, lower BMI and inhalation anaesthesia are the main risk factors for PONV after vitrectomy in adults. Smoking status did not reduce the incidence of PONV in our patients.

Summary

Background and objective: To evaluate and compare the effect of two clinically available central nervous system stimulants, namely doxapram and aminophylline on arousal from sevoflurane anaesthesia and bispectral index. Methods: This randomized, double-blind, placebo-controlled, prospective study was conducted in 90 adult females, ASA I–II, scheduled for elective lower abdominal surgeries at Taipei Medical University Hospital. At 5 min before the completion of surgery, under sevoflurane anaesthesia, patients were divided into three groups to receive doxapram 1 mg kg−1, aminophylline 2 mg kg−1 or saline placebo intravenous. Standard vital signs, end-tidal CO2, end-expiratory sevoflurane concentration, bispectral index and neuromuscular blockade were measured plus clinical parameters of recovery from general anaesthesia. Results: Compared with the control group, patients receiving doxapram or aminophylline showed a similarly faster recovery from sevoflurane anaesthesia correlated with increase in bispectral index. Conclusion: Intravenous administration of doxapram 1 mg kg−1 or aminophylline 2 mg kg−1 hastened the early recovery from sevoflurane anaesthesia. The arousal effect of aminophylline and doxapram appears to be similar.

Summary

Subarachnoid haemorrhage due to rupture of cerebral aneurysms is a multisystem disease. Treatment of the condition in the past has relied on craniotomy and clipping of the aneurysm to prevent a recurrent haemorrhage. There is now emerging evidence to suggest that endovascular treatment of cerebral aneurysms may reduce the morbidity associated with open surgery. The anaesthetic management of interventional neuroradiology also creates new challenges due to the novel approach to treatment. Anaesthetists need to be familiar with this procedure and the management of potential complications. This review provides an overview such considerations.

Summary

The management of thyroid-associated eye disease is reviewed with particular reference to surgical management and its implications for anaesthetists. Experience from a unit undertaking such surgery is presented.

Summary

Background and objective: The optimal depth of insertion of left-sided double-lumen endobronchial tubes is strongly correlated with body height in average-sized adults. However, this relationship has not been studied in below average-sized adult patients. We investigated whether or not there is a clinically useful relationship in below average-sized adult patients. Methods: One hundred and ninety six consecutive adult patients undergoing thoracic surgery under one-lung anaesthesia (body height ≤ 155 cm) were included in this study. Left-sided double-lumen tubes were inserted under the guidance of a fibre-optic bronchoscope. Optimal depth was defined as the proximal surface of the bronchial cuff positioned just below the carina. Results: There was a statistically significant positive correlation between body height and the optimal depth of insertion (r = 0.61, P < 0.0001); however, the correlation coefficient was low. The actual optimal depth of insertion of one patient was even 4.5 cm shorter than that obtained from the equation. Conclusion: Although there was a statistically significant correlation between body height and the optimal depth of insertion of left sided double lumen tubes in adult patients of short stature (≤ 155 cm), clinical application of the equation is not warranted and these tubes should be inserted under direct vision with a fibre-optic bronchoscope.

Summary

Background and objective: The ease of endotracheal intubation has been recently shown to affect the incidence of laryngeal injury. There remains controversy as to whether or not a muscle relaxant is routinely required for tracheal intubation. This study examined conditions of intubation in our routine practice, which employs a relaxant-sparing approach. Methods: All adult patients scheduled for surgery with general anaesthesia were prospectively included. A muscle relaxant was used to facilitate intubation when it was required for the surgical procedure and/or otherwise regarded as necessary by the anaesthesiologist. In the remaining patients, a relaxant-free intubation was performed. Intubating conditions were evaluated in all the patients as well as the post-intubation laryngeal symptoms. Results: Between March and July 2003, 612 patients were consecutively included. A muscle relaxant was used in 32% of patients and no relaxant in the remaining patients (68%). Clinically acceptable intubating scores were observed in 98.4% overall with no significant difference between the two groups. Excellent conditions occurred more frequently in the relaxant group as compared to the relaxant-free group, 87% vs. 72%, P = 0.005. Laryngeal symptoms occurred in 184 (33%) patients with no difference between the two groups. Conclusions: Our relaxant-sparing approach did not increase the incidence of poor conditions of intubation nor laryngeal symptoms. However, excellent conditions occurred more frequently in the relaxant group. A more flexible approach to the issue of the need for neuromuscular blockade prior to intubation is proposed.

Summary

Background and objective: Remifentanil has a short duration of action and constant elimination, which allow administration of high doses, without prolonging recovery. Remifentanil has been compared to alfentanil, as part of a total intravenous anaesthetic technique, where remifentanil provided better anaesthetic conditions than alfentanil, without adverse effect on recovery. However, these results were obtained during anaesthesia involving neuromuscular blockade, which may mask both signs of insufficient anaesthesia and side-effects such as muscle rigidity. The aim of this study was to compare remifentanil with alfentanil for anaesthesia without neuromuscular blockade.

Methods: We performed a prospective, randomized, double-blind, four-centre study to compare remifentanil infusion 15 μg kg−1 h−1 and alfentanil infusion 60 μg kg−1 h−1, using a total intravenous technique for non-paralysed patients, and the laryngeal mask airway for airway management. We enrolled 192 patients, 18–65 yr of age with ASA I–II, undergoing minor surgery. The primary endpoint was the number of patients having pre-defined responses to surgical stimulation. A number of secondary criteria was evaluated to assess undesirable properties of the procedures.

Results: In the alfentanil group, 85% of patients responded to surgical stimulation, vs. 35% in the remifentanil group (P < 0.0001). No difference was found in recovery data, or in any other parameter than those related to insufficient anaesthesia.

Conclusions: The remifentanil-based technique provided significantly better anaesthetic conditions than the alfentanil-based technique in the setting of this study, without causing any significant adverse effects.

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: The use of propofol compared with isoflurane is associated with improved patient comfort and decreased costs. However, as the cost saving, the quicker recovery time and patient comfort may not be evident if sevoflurane is substituted for isoflurane; these two anaesthetic agents were analysed in elderly patients.

Methods: In a prospective randomized study, 96 patients undergoing elective ophthalmic surgery received either total intravenous anaesthesia with propofol (Group P), propofol for induction and sevoflurane for maintenance (Group P/S) or sevoflurane for inhalation induction and maintenance (Group S). Analyses focussed on haemodynamics, the quality of recovery, and the costs for the anaesthetic and the entire procedure.

Results: Bradycardia or hypotension, mainly registered in Groups P and P/S, did not influence patients' recovery. In Group S, postoperative nausea and vomiting occurred frequently, and 50% of patients complained of discomfort during induction. In Group P/S, the costs for anaesthetics and total costs were lower than those in Groups P and S.

Conclusions: Propofol- and sevoflurane-based maintenance of anaesthesia were similar with regard to patient comfort and recovery in the elderly. Cost analysis revealed that it was less expensive to use propofol for induction and sevoflurane for maintenance than to use either propofol or sevoflurane as sole agents for anaesthesia.

Summary

Background and objective: Inflammation promotes hyperalgesia and increases opioid binding protein (α1-acid glycoprotein) inducing increased opioid requirement. To investigate the influence of an acute episode of inflammatory bowel disease in opioid requirement during major abdominal surgery, 17 patients with Crohn's disease, 12 patients with ulcerative colitis and seven patients without any inflammatory process (control group) were prospectively studied. Sufentanil requirements were assessed during surgery.

Methods: Sufentanil administration was adjusted when haemodynamic variables changed more than 20% of preoperative values. In a subgroup of 20 patients (Crohn's disease: 7, ulcerative colitis: 7, control group: 6), plasma concentrations of α1-acid glycoprotein and unbound sufentanil were measured. Total plasma clearance of sufentanil was also determined. Data presented as median (25–75‰) were analysed by non-parametric and ANOVA tests.

Results: Despite similar surgery duration, intraoperative sufentanil requirements were significantly larger in both the Crohn's disease group (0.9 (0.6–1.6) μg kg−1 h−1) and the ulcerative colitis group (1.1 (0.6–1.7) μg kg−1 h−1) than in the control group (0.5 (0.4–0.5) μg kg−1 h−1). Total plasma clearance of sufentanil was larger in patients with inflammatory bowel disease than in the control group. The plasma α1-acid glycoprotein concentration was increased in the inflammatory bowel disease group. However, the free fraction of sufentanil was similar in all three groups. The largest sufentanil consumption in patients with inflammatory bowel disease was observed during time of pain stimulation in the area of referred hyperalgesia from the affected viscus. In the control group, the sufentanil requirement was constant throughout surgery.

Conclusion: Inflammatory bowel disease increases opioid requirement during major abdominal surgery.

Summary

Background and objective: Perioperative hypothermia is generally regarded as undesirable, but its incidence rate in the elective procedures in our hospital and the effect of the preventative measures taken against it were unknown. An initial audit indicated that postoperative hypothermia occurred. Therefore, changes in practice were implemented to address the problem. A further audit was then undertaken to assess the impact of these measures.

Methods: The first audit recorded data from 177 patients undergoing major elective surgical procedures. Variables recorded were: ASA classification, duration of operation, use and description of preventative measures for hypothermia, blood loss, intravenous fluids, and core and peripheral temperatures on arrival and discharge from the recovery room. The subsequent audit included 158 patients undergoing major general, orthopaedic or vascular surgical procedures. Patients had core temperatures measured preoperatively, immediately upon arrival in the recovery room, and just before discharge back to the ward. Core temperatures in both audits were measured using an infrared temperature probe.

Results: The mean body temperature on arrival in the recovery room of patients in the initial audit was 35.5°C (range 32.2–37.2, SD ± 0.74), and in the subsequent audit 36.6°C (33.6–38.2, ±0.72). These differences reached significance (P < 0.0001). This was despite an average duration of surgery of 133.5 (25–330) min in the initial study compared with 154.7 (90–480) min subsequently.

Conclusions: We found that with simple but consistently implemented changes in practice, postoperative hypothermia in elective patients could largely be eradicated.

Summary

Background and objective: The size of the laryngeal mask airway in children is determined by the patient's weight. However, in some instances an alternative method may be wanted. The aim was to search for a new method that would be easy to perform at the bedside.

Methods: The size of the laryngeal mask airway was determined in 183 children by choosing the laryngeal mask that best matched the combined widths of the patient's index, middle and ring fingers. The results were compared with the standard method recommended by the manufacturer's weight-related guidelines. The patients were classified in different groups depending on the laryngeal mask airway sizes determined by both methods. A kappa coefficient evaluated the agreement between both techniques.

Results: The kappa coefficient was 0.81, showing an ‘excellent agreement’ between both methods. The size was the same for both methods in 142 children (78%). The disagreement between both techniques was only of one size in the remaining 41 patients (22%). In such patients, the weight was a borderline value that would indicate a change in the size of the laryngeal mask airway using the classic method.

Conclusions: This new approach is of valid and practical use in children, particularly as an alternative in those situations where the patient's weight is unknown, such as in emergency situations or in those borderline instances where an alternative measurement would be useful.

Summary

Background and objective: This prospective, randomized, controlled study evaluated the effects on oxygenation by applying a selective and patient-specific value of positive end-expiratory pressure (PEEP) to the dependent lung during one-lung ventilation.

Methods: Fifty patients undergoing thoracic surgery under combined epidural/general anaesthesia were randomly allocated to receive zero PEEP (Group ZEEP, n = 22), or the preventive application of PEEP, optimized on the best thoracopulmonary compliance (Group PEEP, n = 28). Patients' lungs were mechanically ventilated with the same setting during two- and one-lung ventilation (FiO2 = 0.5; VT = 9 mL kg−1, inspiratory : expiratory time = 1 : 1, inspiratory pause = 10%).

Results: Lung-chest wall compliance decreased in both groups during one-lung ventilation, but patients of Group PEEP had 10% higher values than patients with no end-expiratory pressure (ZEEP) applied – Group ZEEP (P < 0.05). During closed chest one-lung ventilation, the PaO2 : FiO2 ratio was lower in Group PEEP (232 ± 88) than in Group ZEEP (339 ± 97) (P < 0.05); but no further differences were reported throughout the study. No differences were reported between the two groups in the need for 100% oxygen ventilation (10 patients of Group ZEEP (45%) and 14 patients of Group PEEP (50%) (P = 0.78)) or re-inflation of the operated lung during surgery (two patients of Group ZEEP (9%) and three patients of Group PEEP (10%) (P = 0.78)). Postanaesthesia care unit discharge required 48 min (25th–75th percentiles: 32–58 min) in Group PEEP and 45 min (30–57 min) in Group ZEEP (P = 0.60).

Conclusions: The selective application of PEEP to the dependent, non-operated lung increases the lung–chest wall compliance during one-lung ventilation, but does not improve patient oxygenation.

Summary

Background and objective: The bispectral index, a parameter derived from the electroencephalograph, has been shown to correlate with the loss of consciousness and sedation. This study was designed to assess the effects of bispectral index monitoring on sevoflurane and its recovery profiles.

Methods: Sixty ASA I and II patients undergoing open abdominal surgery were randomized into two groups: one monitored using the bispectral index (Group BIS) and the other without its use (controls). After a standardized induction, anaesthesia was maintained with sevoflurane in both groups. In Group BIS, sevoflurane was titrated to maintain the bispectral index in the range 40–60. In the control group, the administered sevoflurane concentration was adjusted according to the signs of anaesthesia. The end-tidal sevoflurane concentration, bispectral index and routine haemodynamic variables were noted every 5 min during surgery. The consumption of sevoflurane was computed. At the conclusion of surgery operations, the time to ‘open eyes on verbal command’, ‘motor response to verbal command’ and Aldrete's score were recorded by a blinded anaesthesiologist.

Results: The difference in the consumption of sevoflurane was not significant between the groups. Bispectral index monitoring was associated with a reduction of 4.73% in sevoflurane usage and 2.19 mL h−1 was saved.

Conclusions: Bispectral index monitoring during anaesthesia provides only a small advantage related to the need to monitor the depth of anaesthesia.

Summary

Background and objective: In October 2000, we conducted a national postal survey of consultant day case anaesthetists in the UK to explore the range and variation in the practice of anaesthetizing a patient for day case surgery (paediatrics, urology and orthopaedics). The survey was carried out as part of a larger study that comprised a major two-centre randomized controlled trial designed to investigate the costs and outcome of several anaesthetic techniques during day care surgery in paediatric and adult patients (cost-effectiveness study of anaesthesia in day case surgery). We report the findings of this national survey of adult urology and orthopaedic day case anaesthetic practice in the UK.

Methods: The survey used a structured postal questionnaire and collected data on the duration of the surgical procedure; the use of premedication; the anaesthetic agents used for induction and maintenance; the fresh gas flows used for anaesthesia; the use of antiemetics; and the administration of local anaesthesia and analgesia.

Results: The overall response rate for the survey was 74% (63% for urology, 67% for orthopaedics). The survey indicated the following practice in adult urology and adult orthopaedic day case surgery: 6 and 12% used premedication; propofol was the preferred induction agent (96 and 97%) and isoflurane the preferred maintenance agent (56 and 58%); 32 and 41% used prophylactic antiemetics; 86 and 93% used a laryngeal mask.

Conclusions: This survey identifies the variation in current clinical practice in adult day surgery anaesthesia in the UK and discusses this variation in the context of current published evidence.

Summary

Background and objective: In October 2000, we conducted a national postal survey of day case consultant anaesthetists in the UK to explore the range and variation in practice of anaesthetizing a patient for day case surgery (paediatrics, urology and orthopaedics). This paper reports the findings of this national survey of paediatric day case anaesthetic practice carried out as part of a major two-centre randomized controlled trial designed to investigate the costs and outcome of several anaesthetic techniques during day care surgery in paediatric and adult patients (cost-effectiveness study of anaesthesia in day case surgery).

Methods: The survey used a structured postal questionnaire and collected data on the duration of surgical procedure; the use of premedication; the anaesthetic agents used for induction and maintenance; the fresh gas flow rates used for general anaesthesia; the use of antiemetics; and the administration of local anaesthesia and analgesia.

Results: The overall response rate for the survey was 74 and 63% for the paediatric section of the survey. Respondents indicated that 19% used premedication, 63% used propofol for induction, 54% used isoflurane for maintenance, 24% used prophylactic antiemetics and 85% used a laryngeal mask. The findings of this national survey are discussed and compared with published evidence.

Conclusions: This survey identifies the variation in clinical practice in paediatric day surgery anaesthesia in the UK.

Summary

Background and objective: Because gastric mucosal PCO2 must be referenced to arterial values via a gastric-to-arterial PCO2 gap (Pg–aCO2), the gastric-to-end-tidal PCO2 difference (Pg–etCO2) may be proposed as a surrogate method to monitor Pg–aCO2. However, the influence of arterial-to-end-tidal PCO2 (Pa–etCO2) on its value remains unknown. Pa–etCO2 may be enhanced by a low cardiac output and subsequent reduced perfusion of the lungs. This study was designed to compare such gaps observed during abdominal surgery in patients with or without preoperative cardiac dysfunction.

Methods: Haemodynamic, metabolic and tonometric variables were measured in seven patients with Crohn's disease and in five patients with chronic heart failure scheduled for abdominal surgery. Data were collected before skin incision (T0); at extractor placement (T1), 30 (T2) and 60 (T3) min later; at organ extraction (T4), 30 (T5) and 60 (T6) min later, and at the end of surgery (T7).

Results: Gradients appeared larger in the cardiac group. The difference was significant for Pg–etCO2 during the whole study period, while it was only reached at T1–T2 for Pa–etCO2 and at T5–T6 for Pg–aCO2. Gaps did not change significantly over the peroperative time points in either group. No major haemodynamic variations were registered in either group.

Conclusions: In patients with preoperative chronic heart failure, Pg–etCO2 remained constant throughout a major general surgical procedure and was only moderately influenced by the Pa–etCO2 gap. In these patients, Pg–etCO2 may be used as a reliable index of gastrointestinal perfusion after control of PaCO2.

Summary

Background and objective: The study investigated the impact of induced arterial hypotension for the facilitation of endovascular stent-graft placement in patients with thoracic aortic aneurysm on cerebral blood flow velocity and neurological/neurocognitive outcome.

Methods: In 27 ASA III patients, cerebral blood flow velocity was recorded during induced arterial hypotension for endovascular stent-graft placement using transcranial Doppler sonography and the Folstein Mini Mental State Examination and the National Institute of Health Stroke Scale were performed before and after the intervention.

Results: Mean arterial pressure was decreased <50 mmHg, and in 22 patients it was <40 mmHg. Diastolic cerebral blood flow velocity decreased by 59%. Postoperatively, six of 21 patients exhibited changes in the Folstein Mini Mental State Examination and four of these six patients in the National Institute of Health Stroke Scale as indices of new-found neurocognitive dysfunction, but there were no signs of stroke. Loss of the diastolic blood flow profile was detected in two of six patients with new-found neurocognitive dysfunctions and in 18 of 21 patients with no new-found neurocognitive dysfunction. Changes in the Folstein Mini Mental State Examination on postoperative day 1 were correlated to the pre-procedural Folstein Mini Mental State Examination, but not to the time spent with a mean arterial pressure <50 mmHg, <40 mmHg or with a loss of diastolic blood flow profile.

Conclusions: Transcranial Doppler sonography visualizes the individual effect of induced hypotension and the period of intracranial circulatory arrest during aortic stent-graft placement. However, transient new-found neurocognitive dysfunctions occur independently of the transcranial Doppler data, and are in close correlation to the neurocognitive state before the procedure. The results suggest that induced arterial hypotension is not the major factor for postoperative new-found neurocognitive dysfunction.