In a Swedish nation-wide study, 1196 members of the general public, and 121 physicians and 339 nurses drawn from 29 intensive care units were questioned about the use of ventilator treatment for severely ill patients. Response rates were 64%, 88% and 86%, respectively. Two typical case history scenarios were presented: one describing a conscious and competent patient with pneumonia and severe cancer, and the other describing a patient who had been comatose for 1 month following head trauma. In the case of the cancer patient, 49% of the general public, 63% of the physicians and 59% of the nurses answered that theywould wish that the ventilator treatment be discontinued, if they were the patient. In the case of the comatose patient, 48% of the general public, 82% of the physicians and 70% of the nurses answered that they would wish that the ventilator treatment to be discontinued, if they were a relative of the patient. Respondents own preferences, in the three groups,for life support favoured withdrawal of ventilator treatment.

Dopamine decreases gastric tone and may therefore influence gastrointestinal motility. The aim of this investigation was to study the effects of a continuous infusion of dopamine on gastric emptying and orocaecal transit time. Nine healthy male volunteers were studied on two occasions in a randomized order. All volunteers received on separate days a continuous infusion of dopamine 5 μg kg−1 min−1 on one occasion and normal saline on the other occasion. Gastric emptying was measured by the paracetamol absorption test and orocaecal transit time by the hydrogen breath test. During the dopamine infusion the area under the paracetamol concentration curve was significantly smaller than during control conditions (P=0.02). Orocaecal transit time was prolonged during the dopamine infusion (P=0.02). Dopamine delays gastric emptying and prolongs orocaecal transit time.

It has been suggested that epidural anaesthesia may increase blood flow in free flaps on the lower extremity. The objective of the present study was to test this hypothesis in 21 patients undergoing reconstructive surgery of the lower extremity with free muscle (n=8), fasciocutaneous (n=6) or musculocutaneous (n=7) flaps. Microcirculatory blood flow was measured continuously with a multichannel laser Doppler flowmetry, both in muscle and skin of the free flap as well as in the intact skin and muscle on the same extremity. After completion of surgery, general anaesthesia was continued and the epidural block was induced by an injection of 2% lignocaine-hydrochloride into a pre-operatively inserted and tested epidural catheter. The epidural block caused no change in microcirculatory flow in the intact skin and muscle, however, it resulted in a marked decrease in microcirculatory blood flow in all the free flaps studied (20–30%; P < 0.05). The epidural block also caused a significant decrease in mean arterial blood pressure, from 85 (±2.8) mmHg to 68 (±2.8) mmHg (P < 0.01). It was concluded that epidural anaesthesia may decrease microcirculatory blood flow in free flaps on the lower extremity by diverting flow away from the flap to normal intact tissues (a steal phenomenon).

A review was undertaken of all 190 patients who were referred over 7 years, from 1991 to 1997 inclusive, for an epidural blood patch as a treatment for headache after dural puncture. The patterns of referral and symptoms, the distributions of age and gender and the effectiveness of the blood patch were examined. Most of the referrals (n=153) were after deliberate diagnostic dural puncture in neurology and neuroradiology, with a minority (n=28) used for anaesthesia and obstetrics, which were mostly inadvertent. Another nine cases were related to placement of an intrathecal catheter. The numbers of referrals per year reached a maximum in 1995 before falling again, a curious inverse relation to the number of invasive neuro-radiological diagnostic procedures. Most of the patients were between 30 and 50-years-old, with 25 younger than 30 and 14 older than 60. Women accounted for 70% of the referrals for headache, although the gender ratio amongst patients subjected to at risk procedures appeared closer to 50:50. Neckache accompanied the headache in 85% of cases, auditory problems were volunteered by three patients and one patient had diplopia for 6 weeks. Of the 190 patients who were referred, 186 received at least one patch, the symptoms in the remaining four being too mild or atypical to warrant blood patch treatment. This provided initial relief in all but two patients, one of whom received a further epidural blood patch with no effect. There was sustained relief of symptoms in 136 and a partial relapse in 38 patients, which resolved without needing any further blood patch. A second patch was provided for seven patients and a third for three patients, of whom two were cured. Of the patients who needed more than one blood patch, nine were after inadvertent dural puncture with a Tuohy needle and, of these patients, six were in labour. A total of 200 patches were provided in all for the 186 patients and all but three patients had a satisfactory outcome. Epidural blood patches are effective in treating headache after dural puncture, but less successful than is commonly believed, especially after inadvertent dural taps. A relapse after treatment does not always require a second patch. Specialities other than anaesthesia seemed reluctant to accept the benefits in both cost and comfort of using needles of improved design for dural puncture.

Gamma-hydroxybutyrate (GHB) may well be developed as an alternative for optional sedation during spinal anaesthesia. As in the case of propofol (PRO), GHB has good sedative properties associated with cardiovascular and respiratory stability. When used as a narcotic agent, recovery times are variable (e.g. > 30 min); in contrast, sedative dosages, as used in intensive care patients (e.g. 10–20 mg kg−1 h−1), result in adequate clinical recovery. The goal of the present study was to compare the clinical properties of GHB and PRO after continuous administration during spinal anaesthesia (SPA). Thirty patients (ASA I and II) received either GHB (n=15) or PRO (n=15) at random. Patients refusing sedation (n=15) received 0.9% saline (control). At eight defined time points, haemodynamic (BP, HR), respiratory (RR, RMV, Pao2, Spo2, Peto2, Petco2, ̇Vo2, ̇Vco2) and endocrinological parameters (plasma concentrations of noradrenaline and adrenaline) as well as the clinical side-effects were assessed simultaneously. With both sedatives, the desired level of sedation was achieved. Recovery times ranged between 1.7±0.9 min with PRO and 6.1±4.9 min with GHB. GHB provided stable haemodynamic conditions without clinically relevant respiratory depression. In contrast, PRO caused a decrease in mean arterial pressue (MAP) of 15%, whereas respiratory minute volume was decreased by 53% (with periods of apnoea, Spo2<90%). ̇Vo2 and ̇Vco2 correlated with respiratory minute volume (GHB, PRO, control). Plasma noradrenaline and adrenaline concentrations remained nearly constant in the GHB and control groups and declined during sedation with PRO. Both GHB and PRO are suitable for optional sedation during spinal anaesthesia. Control and recovery are acceptable for clinical purposes. It seems that GHB and PRO have similar haemodynamic, respiratory and endocrinological characteristics. Therefore, GHB may serve as an alternative for the established management of continuous sedation during SPA with PRO.

Local anaesthesia combined with conscious sedation is becoming a popular technique for implantation of cardioverter-defibrillator devices. Propofol was given to provide loss of consciousness during defibrillation shock administration, for induced ventricular fibrillation testing. Propofol was found to decrease QT interval and QT dispersion in two patients with idiopathic prolonged QT interval and QT dispersion. The findings of the procedure are reported.

Concerns about life support equipment accompanying the critically ill patient have to date made magnetic resonance imaging (MRI) studies of this patient group the exception. We present here a series of tests performed on an IVAC P3000 infusion pump to investigate its suitability for the magnetic resonance imaging environment. We investigate safety, pump performance and image quality issues. The pump was housed at the end of the patient couch to prevent motion towards the scanner. Gravimetric tests found the pump to work within acceptable parameters at a static field of 10 mT. Image interference issues were addressed.

In this study, we have sought to establish whether N2O and ketamine alter the bispectral index during propofol–fentanyl anaesthesia. Fourteen surgical patients were randomly assigned to one of two groups: the N2O group (n=7) and the ketamine group (n=7). In both groups, anaesthesia was induced with propofol 1.5–2 mg kg−1 and fentanyl 2 μg kg−1 and maintained with propofol 5–7 mg kg−1 hr−1 to target the bispectral index between 40 and 50. After the bispectral index value had stabilized the propofol infusion rate was fixed. In the N2O group, the following concentrations of N2O were subsequently inhaled at 20-min intervals; 20, 40, 60 and 70%, and then N2O was terminated. In the ketamine group, ketamine (0.4 mg kg−1+1.0 mg kg−1h−1) was given. The bispectral index and 95% spectral edge frequency were recorded 20 min after each change in concentration of N2O or ketamine infusion. The bispectral index and 95% spectral edge frequency did not change significantly in the N2O group, but increased significantly from 44.1±0.7 and 16.0±0.5 to 58.6±1.4 and 19.5±0.3 (P <0.01), respectively, in the ketamine group. Additional N2O or ketamine did not decrease the bispectral index and 95% spectral edge frequency values. The depth of sedation should be assessed carefully using a bispectral index monitor when these anaesthetic agents are used together.

We studied the movement response to skin incision in 68 adult (males/females) ASA I–II patients receiving propofol±fentanyl intravenous anaesthesia using the bispectral index and 95% spectral edge frequency monitoring with an A-1050 EEG monitor. Following Ethics Committee approval, patients were randomly assigned to one of the following four treatments: Group P (n=17): propofol infusion, 1 mg kg −1 min−1 intravenous for 2 min, followed by propofol infusion, 200 μg kg−1 min−1, until skin incision; Group PF1 (n=17): fentanyl bolus, 1 μg kg−1 intravenous+ propofol infusion as in Group P; Group PF2 (n=17): fentanyl bolus, 2 μg kg−1 intravenous+ propofol infusion as in Group P; and Group PF3 (n=17): fentanyl bolus, 3 μg kg−1 intravenous+ propofol infusion as in Group P. The bispectral index and 95% spectral edge frequency were monitored continuously and recorded prior to induction of anaesthesia (base-line) and at skin incision. Twelve, 10, 4 and 4 patients responded to skin incision in Groups P, PF1, PF2 and PF3, respectively (P and PF1 vs. PF2 or PF3; P=0.0001, and 0.006). The bispectral index and 95% spectral edge frequency were significantly lower at skin incision compared with the base-line values in all the four treatment groups. However, only bispectral index values were significantly lower in the nonmovement as compared with the movement (M) category (32.6±8.9 vs. 37.4±10.3; P=0.04). Though deeper levels of hypnosis to lower bispectral index and 95% spectral edge frequency values may be effective in preventing the movement response to skin incision, provision of adequate analgesia rather than lower bispectral index and 95% spectral edge frequency (clinical maintenance) values may be more reliable for preventing the response to skin incision as bispectral index and 95% spectral edge frequency measure the hypnotic component of the anaesthetic effect. Lower bispectral index values may be more discriminatory as compared with 95% spectral edge frequency values for preventing the movement response to skin-incision.

The effects of controlled hypotension induced with trimethaphan (TMP), nitroglycerin (TNG) or prostaglandin E1 (PGE1) during sevoflurane anaesthesia on hepatic function were studied in 28 patients undergoing spinal fusion surgery. Patients were randomly divided into three groups to receive TMP (group A, n=10), TNG (group B, n=10) or PGE1 (group C, n=8). Anaesthesia was maintained with N2O and sevoflurane. The mean arterial blood pressure was maintained at 60 mmHg for 90 min. Measurements included arterial ketone body ratio (AKBR-acetoacetate/3-hydroxybutyrate), SGOT, SGPT, LDH, blood glucose and blood gases were made. Measurements were taken before hypotension, 60 min and 90 min after starting hypotension, 60 min after recovery from hypotension and on the post-operative day. AKBR showed no significant change. SGOT, SGPT and LDH were within normal limits. Controlled hypotension induced with TMP, TNG or PGE1 under sevoflurane anaesthesia in surgical patients did not cause hepatocellular damage.

As elevated endothelin-1 (ET-1) levels have been reported in systemic inflammatory diseases, the role of ET-1 as a promoter of inflammatory reactions is currently under investigation. The purpose of this study was to investigate the potential influence of ET-1 on systemic vascular pressure and immune function in terms of blood clearance and organ distribution of injected Escherichia coli in a rabbit model. To enable quantification of the clearance process, defined numbers of exogenous E. coli (108 cfu) were injected intravenously 60 min after starting the infusion of ET-1 (0.2 μg kg−1 min−1; n=9) or after saline infusion (controls, n=9). Parameters monitored were arterial blood pressure, airway pressure, serum lactate concentrations and rates of bacterial elimination from the blood. At 180 min after E. coli injection, the animals were killed, and tissue samples of liver, kidney, spleen and lung were collected for bacterial counts. ET-1 infusion produced an increase in mean arterial pressure (83.9±3.9 mmHg vs. 50.1±4.1 mmHg at 120 min; P< 0.01) associated with higher serum lactate concentrations (12.6±1.3 vs. 5.4±0.3 mg dL−1; P< 0.001) and a delayed bacterial elimination from the blood compared with controls. Furthermore, there was increased colonization of the lungs (3.6±0.5×103 cfu vs. 745±120 cfu; P<0.01), spleen (142.4±45.4×103 cfu vs. 22.7±5.2×103 cfu; P<0.05) and kidney (758±329 vs. 357±151 cfu; NS), reflecting a reduced bacterial killing function.

The acute influence of therapeutic doses of theophylline on cerebral blood flow velocities during general anaesthesia induced either by halothane or isoflurane has not been elucidated previously. The aim of this study, was therefore to investigate these effects during steady state anaesthetic conditions in anaesthetized patients using transcranial Doppler sonography. Thirty-four Patients were investigated. Anaesthesia was maintained either with 1 MAC (minimum alveolar concentration) halothane (n=16) or 1 MAC isoflurane (n=18); FiO2: 40%; end-expiratory pCO2: normocapnia. Theophylline administration was performed before surgery by infusing 6 mg kg−1 over a period of 7.5 min. Measurements were recorded prior to theophylline administration, and immediately after 2 mg kg−1 (2.5 min), 4 mg kg−1 (5 min) and 6 mg kg−1 (7.5 min), as well as 5, 10, 15, 20, 30 and 45 min after theophylline administration. Recorded variables included blood pressure, heart rate, arterial oxygen saturation, end-expiratory pCO2, body temperatures, middle cerebral artery blood flow velocity and pulsatility index. Theophylline administration was well tolerated by all study subjects. Heart rate, blood pressure, body temperatures, arterial oxygen saturation and end-expiratory pCO2 remained constant during the whole examination period. Following theophylline, mean blood flow velocity decreased by 25% in the halothane and by 30% in the isoflurane group (P< 0.05). By the end of the examination period, mean blood flow velocity had not yet recovered to the initial values whereby in both groups the mean blood flow velocity was 26% below the initial values. In the isoflurane group, the pulsatility index increased by about 20% (P< 0.05) and remained high until the end of the examination. In the halothane group, however, there were no changes in the pulsatility index. Our results show a remarkable, significant and simultaneous decrease in blood flow velocity in the middle cerebral artery associated with theophylline administration during halothane and isoflurane anaesthesia in man.

The purpose of this study is to compare the incidence of undesirable respiratory events when the laryngeal mask airway is either removed from patients who are fully awake or from patients who are deeply anaesthetized. Three-hundred patients aged 1.5–81 years were randomly assigned to have their laryngeal mask airway removed either when deeply anaesthetized or after airway reflexes had returned. The occurrence of adverse respiratory events (coughing, oxygen desaturation and airway obstruction) was recorded. Airway obstruction after laryngeal mask airway removal was evident in 20% of patients in the deep anaesthesia group and in 8% of patients in the awake group (P=0.007). In spite of this finding, oxygen desaturation in children of less than 6 years of age (SaO2 < 96%) occurred most frequently after awake removal (31.3%) compared with deep anaesthesia removal (4.5%) (P=0.023).

This study was designed to examine the effect of volume loading on haemodynamic responses and regional cardiac function in dogs subjected to two infusion rates of propofol. Instrumentation was established to measure aortic and left ventricular pressures, cardiac output and myocardial segmental lengths. Measurements were taken during two successive infusion rates of propofol: 0.2 (P0.2) and 0.4 (P0.4) mg kg−1 min−1. One group (VL+) (n=6) received volume loading (dextran 40, 10 mL kg−1 h−1), the other group (VL−) (n=6) received only basal perfusion (Ringer solution, 2 mL kg−1.h−1). Regional blood flows were measured by radio-labelled microspheres. P0.4 induced a decrease in cardiac output and in dP/dtmax. End-diastolic length decreased with propofol without any difference between groups. Regional contractility was not modified by propofol or by volume loading. P0.4 decreased endocardial and epicardial blood flow in the VL-group only. Renal, small intestine and large intestine blood flows decreased in both groups with P0.4. P0.2 did not alter regional blood flows significantly. It was concluded that in this model, propofol infusion at 0.4 mg kg−1 min−1 induced splanchnic, renal and myocardial hypoperfusion in animals not submitted to a mild fluid loading. Fluid loading allowed myocardial perfusion to be maintained but could not prevent a marked decrease in splanchnic and renal perfusion.

In order to compare interscalene brachial plexus block performed with ropivacaine or bupivacaine, 45 healthy, unpremedicated patients, undergoing elective shoulder surgery, were randomly allocated to receive interscalene brachial plexus anaesthesia with 20 mL of either ropivacaine 0.75% (n=15), ropivacaine 1% (n=15), or bupivacaine 0.5% (n=15). Readiness for surgery (loss of pinprick sensation from C4 to C7 and inability to elevate the limb from the bed) was achieved later with bupivacaine 0.5% (28±15 min) than with ropivacaine 1% (10±5 min) (P=0.005) and ropivacaine 0.75% (15±8 min) (P=0.0005). No differences in success rate were observed between the three groups; however, seven patients receiving bupivacaine 0.5% required intra-operative analgesic supplementation (fentanyl 0.1 mg intravenous) compared with one patient receiving ropivacaine 0.75%, and two patients treated with ropivacaine 1% (P=0.02). The time from the block placement to first request for pain medication was similar in the three groups (10.7±2 h, 11±2.4 h, and 10.9±3.9 h after 0.75% and 1% ropivacaine or 0.5% bupivacaine, respectively). We conclude that interscalene brachial plexus block performed with 20 mL of either 0.75% or 1% ropivacaine allows for a prolonged post-operative pain relief, similar to that provided by bupivacaine 0.5%, with short onset time of surgical anaesthesia.

We compared the performance of the size 5 laryngeal mask airway in 20 paralysed anaesthetized male patients and 20 male cadavers (6–24 h post-mortem). Groups were matched for height and weight. Airway sealing pressure, in vivo intracuff pressure and anatomical position (judged fibre-optically) were documented at zero volume and after each additional 10 mL up to 40 mL. All laryngeal mask airways were inserted at the first attempt and insertion times were similar. There were no differences in airway sealing pressure, in vivo intracuff pressure or fibre-optic position between the groups. We conclude that the performance of the laryngeal mask airway is similar for fresh cadavers and paralysed anaesthetized patients. This may have implications for laryngeal mask airway research and training.

After an intubating dose of rocuronium satisfactory intubating conditions are achieved before the onset time at the adductor pollicis. We examined the possibility that measurement of the relaxation of the masseter muscle is a more appropriate guide when determining the intubating time. Simultaneous accelerometry with a 0.1-Hz single twitch stimulation of the chin and thumb was performed in 20 patients after 0.6 mg kg=1 rocuronium. We observed a significantly more brief mean lag time and onset time at the masseter muscle (22.5 and 61 vs. 32.5 and 160 s). The corresponding mean relaxation at the onset time was also significantly more pronounced at the masseter muscle (99.6 vs. 97.6%). A mean onset time at the masseter muscle of 61 s as produced by rocuronium corresponds clinically with excellent or good intubating conditions. From these results, we suggest that measurement of the onset time of muscle relaxation at the masseter muscle appears to be a better predictor of good intubating conditions than measurements made using the adductor pollicis muscle after administration of rocuronium.

One may have to use a monitor of cortical suppression to maintain the optimal level of sedation and hypnosis. The bispectral index (BIS), a processed EEG parameter, which incorporates coupling along with the frequency and amplitude of EEG waveforms, has been proposed as a measure of the pharmacodynamic anaesthetic effect on the central nervous system. The numerical value of BIS varies from 0 to 100 (no cerebral activity to fully awake patient). In order to achieve the desired level of propofol sedation or hypnosis, a target concentration of propofol at the effect site or in the blood must be delivered. Alternately, one may use BIS monitoring to monitor hypnosis or sedation levels or to reflect propofol concentrations in the blood. Significant correlations between plasma propofol concentrations and BIS values (r=0.68–0.78) have been reported by many investigators. During propofol-induced sedation, BIS values may be maintained above 75 to prevent airway obstruction and hypoxia. During propofol intravenous anaesthesia, BIS values from 40 to 60 have been proposed to maintain the desired level of hypnosis, with values below 50 associated with an insignificant probability of recall. However, the major limitation of the BIS monitor (monitor of hypnosis) relates to the fact that balanced anaesthesia comprises hypnosis, areflexia and analgesia and requires the administration of hypnotic agents, muscle relaxants and analgesics to achieve the desired clinical effects. Therefore, besides using the BIS value guidelines, one may also consider the haemodynamic, autonomic and somatic responses of the patient, the anaesthetic technique and the surgical interventions before deriving definite conclusions about the overall anaesthetic state of the patient.

We have investigated the cardiovascular and plasma noradrenaline response to surgical incision under sevoflurane anaesthesia and determined the end-tidal concentration of sevoflurane that blocks the adrenergic response or responses to surgical incision (MACBAR) and changes in mean arterial pressure (MAP) in response to surgical incision (MACBCR) in 50% of women. We randomly assigned 64 female patients, aged 20–49 years, to eight groups according to end-tidal sevoflurane concentration: 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0% and 8.5%. All patients received only sevoflurane anaesthesia. An increase of 10% or more from prestress (incision) values of MAP or plasma noradrenaline concentration was considered a positive response. The probability of no response to stress was analysed using logistic regression to obtain the probability of no response vs. end-tidal sevoflurane concentration and the best-fit curve from the maximum likelihood estimators of the model parameters. MACBAR (mean±SE) was 8.0±0.2%, MACBCR was 7.9±0.2%. However, such high doses of sevoflurane cannot be used clinically because of their high toxicity. It may be preferable to combine sevoflurane with other anaesthetics to reduce haemodynamic responses to strong stimulation.