Summary

Background and objective: Regional anaesthesia has not been recommended as an anaesthetic method for penetrating eye injuries because it is suspected to aggravate the injury already present. After having successfully managed the treatment of a penetrating eye injury under combined peri- and retrobulbar block in an ASA IV patient, it was decided to evaluate this anaesthetic method further in the treatment of such emergency cases.

Methods: Twenty adult patients with penetrating eye injuries with a maximum wound length of 8 mm extending up to 4 mm posteriorly from the limbus were operated on under combined peri- and retrobulbar anaesthesia. Eighteen patients receiving general anaesthesia served as controls.

Results: The mean (range) volume injected for a satisfactory peribulbar retrobulbar block was 7.4 (6.5–8.0) mL, six patients needed an additional retrobulbar injection before surgery (2.9, range 2–4, mL). All patients receiving regional anaesthesia were satisfied with the anaesthetic method and the surgeons considered the surgical conditions as good. No problems relating to local anaesthesia were observed or reported by any of the patients.

Conclusions: In the hands of an experienced anaesthesiologist and under certain conditions, regional anaesthesia appears to be suitable for adult patients having penetrating eye injuries.

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: Acute hiccup is a minor complication that can occur during sedation or general anaesthesia. The disorder can disturb the surgical field, might interfere with lung ventilation or could hamper diagnostic procedures. The objective was to perform a systematic search for interventions aimed at treating hiccup occurring during anaesthesia or sedation.

Methods: A systematic search for reports describing interventions to treat hiccup in conjunction with anaesthesia was carried out (MEDLINE, EMBASE, Cochrane-Library, manual screening of reference lists and review articles, up to December 2001). Search terms were ‘hiccup’, ‘singultus’ or ‘hiccough’.

Results: Twenty-six reports involving approximately 581 patients focused on hiccup remedies in the anaesthesia setting. Only one report was substantiated by a randomized controlled trial. This investigated methylphenidate 10 mg intravenously in 51 patients, which did not show a beneficial effect compared with placebo. Hiccup was a self-limiting phenomenon. Case series and case reports focused on various systemically applied drugs in 12 reports, stimulating techniques (e.g. pharyngeal stimulation) in seven, topical applied remedies (e.g. intranasal ice-cold water) in four, and ventilation techniques (e.g. continuous positive pressure ventilation) in two.

Conclusions: A large variety of interventions have been proposed for the treatment of hiccup during anaesthesia and sedation. However, perioperative treatment is still based on empirical findings and no treatment is ‘evidence-based’. Thus, no valid recommendations for the treatment of hiccup can be derived. Uncontrolled observations are inadequate to establish treatment efficacy.

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.

Summary

Background and objective: A need exists for a safe and effective oral preanaesthetic medication for use in children undergoing elective surgery. The study sought to define the dose of oral ketamine that would facilitate induction of anaesthesia without causing significant side-effects.

Methods: We studied 80 children undergoing elective surgery under general anaesthesia who received oral ketamine 4, 6 or 8 mg kg−1 in a prospective, randomized, double-blind placebo controlled study. We compared the reaction to separation from parents, transport to the operating room, the response to intravenous cannula insertion and application of an anaesthetic facemask, the induction of anaesthesia and recovery from anaesthesia.

Results: In the group receiving ketamine 8 mg kg−1, the children were significantly calmer than those of the other groups, and anaesthesia induction was more comfortable. Recovery from anaesthesia was longer in the group receiving ketamine 8 mg kg−1 compared with the other groups, but no differences between the groups were observed after 2 h in the recovery room.

Conclusions: It is concluded that oral ketamine 8 mg kg−1 is an effective oral premedication in inpatient children undergoing elective surgery.

Summary

Background and objective: Adenosine infusions have been shown to reduce requirements of anaesthetics, to decrease the need for postoperative analgesics and to attenuate hyperaesthesia related to neuropathic pain. We decided to investigate the effects, beneficial or otherwise, of an adenosine infusion administered during surgery. A brachial plexus block was used to produce anaesthesia for the surgery.

Methods: Sixty adults undergoing upper extremity surgery were included in the study. Brachial plexus block was performed via an axillary approach with lidocaine 1.25% and epinephrine 1/200 000 (40 mL). Patients were randomly assigned to two groups. During surgery, saline (control) or adenosine 80 μg kg min was infused intravenously in a double-blind fashion for 1 h. Visual analogue scores every 4 h, analgesic consumption, time to first spontaneous pain sensation, time to first rescue analgesic and adverse effects were noted during the first 24 h.

Results: Vital signs were stable in both groups throughout surgery. During the adenosine infusion, one patient fainted while another complained of palpitations and tightness of the chest; both patients were excluded from further analyses. The time to first sensation of pain was significantly longer in the adenosine group compared to the control group (438 ± 387 vs. 290 ± 227 min, P = 0.02). The time to first rescue analgesic, the visual analogue scale scores and analgesic consumption in the postoperative period were similar.

Conclusions: In patients undergoing surgery with an axillary plexus block, a perioperative adenosine infusion prolongs the duration of postoperative analgesia to some extent. However, the time to first rescue analgesic, total analgesic requirements and pain scores were unchanged; the risk of potentially serious adverse effects is high. This therapy cannot be recommended.

Summary

Background and objective: Trazodone hydrochloride is used in the treatment of neuropathic pain. However, the analgesic effects of trazodone on neuropathic pain are controversial. The study was undertaken to determine the analgesic effect of trazodone on a chronic constriction injury model.

Methods: We tested the effect of trazodone on thermal hyperalgesia due to a chronic constriction injury of the sciatic nerve in rats and examined the effects of lesions in the descending and ascending serotonergic system induced by 5,7-dihydroxytriptamine (5,7-DHT).

Results: The analgesic effects of trazodone showed a clear dose dependency. Furthermore, the analgesic effect of trazodone was observed in rats injected with 5,7-DHT into the dorsal raphe nucleus and medial raphe nucleus.

Conclusions: The results suggest that a mainly serotonergic descending pain control pathway mediates the analgesic effects of trazodone.

Summary

Background and objective: This study examined the quality of analgesia together with the side-effects produced by tramadol compared with morphine using intravenous patient-controlled analgesia during the first 24 h after thoracotomy.

Methods: Forty-four patients scheduled for thoracotomy were included in the study. Morphine 0.3 mg kg−1 was given interpleurally 20 min before a standard general anaesthetic. In the postanaesthetic care unit, the patients were randomly allocated to one of two groups to self-administer tramadol or morphine using a patient-controlled analgesia device throughout a 24 h period. The patient-controlled analgesia device was programmed to deliver tramadol 20 mg as an intravenous bolus or morphine 2 mg with a lockout time of 10 min.

Results: Mean cumulative morphine and tramadol consumption were 48.13 ± 30.23 and 493.5 ± 191.5 mg, respectively. There was no difference in the quality of analgesia between groups. Five (26.3%) patients in the tramadol group and seven (33%) in the morphine group had nausea, and three of the latter patients vomited. The incidence rate of vomiting with tramadol was 5.2%. All vital signs were within safe ranges. Sedation was less in the tramadol group, but not statistically significant.

Conclusions: In this clinical setting, which includes interpleural morphine pre-emptively, postoperative analgesia provided by tramadol was similar to that of morphine at rest and during deep inspiration. Side-effects were slight and comparable between the patients receiving morphine and tramadol.

Summary

Background and objective: Although midazolam is commonly given orally to infants and small children for premedication, the taste is sometimes unacceptable even when mixed with syrup. We tested the efficacy and safety of oral fentanyl compared with oral midazolam in a randomized open-label study.

Methods: Fifty-one children, aged 12–107 months and weighing 10–25 kg, were randomly assigned to fentanyl or midazolam treatment groups. Midazolam (5 mg) or fentanyl (0.1 mg) was given orally from a small bottle with a small orifice 30 min before transfer to the preoperative holding room. The excitation–sedation conditions of the patients were assessed before and after general anaesthesia.

Results: The preoperative scores did not differ significantly between the two groups. No major complications were observed in either group. Postoperative vomiting occurred in 5 of 27 (18.5%) patients treated with oral fentanyl and in none of 24 of those treated with midazolam.

Conclusions: Oral administration of fentanyl 30 min before entrance to the holding room for an operation from a bottle with a small orifice is a premedication option for children between 1 and 8 yr of age.

Summary

Background and objective: This study investigated the distribution of pressures within a model trachea, produced by five different tracheal gas insufflation devices. The aim was to suggest a suitable design of a tracheal gas insufflation device for clinical use.

Methods: Each device was tested using insufflation flow rates of 5 and 10 L min−1. For each flow rate, the pressure within the tracheal model was measured at 33 fixed points.

Results: The Boussignac tracheal tube produced the most even pressure distribution, while a reverse-flow catheter produced pressure changes of the smallest magnitude.

Conclusions: We suggest that catheters producing the lowest pressure changes are likely to be safer for clinical use.

Summary

Background and objective: Rocuronium and, to a lesser extent, vecuronium can induce burning sensations associated with withdrawal reactions during administration. Dermal microdialysis in human and electrophysiological recordings of nociceptors in mouse skin were used to elucidate the underlying mechanisms of pain induction.

Methods: Microdialysis catheters were inserted intradermally into the forearm of 10 volunteers and were perfused with two different concentrations of rocuronium and vecuronium (1 and 10 mg mL−1) or a control. Dialysis samples were taken every 15 min and analysed for protein, histamine, tryptase and bradykinin content. Pain intensity was rated on a numerical scale of 0–10. In a parallel design, activation of cutaneous nociceptors was assessed directly in a skin–nerve in vitro preparation of the mouse hind paw. The receptive fields of identified single C-nociceptors (n = 12) were superfused with rocuronium or vecuronium solutions (10 mg mL−1) at physiological pH.

Results: In accordance with clinical observations, microdialysis of rocuronium (10 mg mL−1) induced sharp burning pain (NRS 4.1 ± 1.8), whereas vecuronium given in the usual clinical concentration (1 mg mL−1) induced only minor pain sensations (NRS 0.6 ± 1.3). At equimolar concentrations, pain sensation and concomitant mediator release evoked by both drugs were similar. No correlations were found between pain rating and mediator release. In the in vitro preparation, C-fibres showed a consistent excitatory response with rapid onset after stimulation with vecuronium as well as rocuronium (differences not significant).

Conclusions: The algogenic effect of aminosteroidal neuromuscular blocking drugs can be attributed to a direct activation of C-nociceptors.

Summary

Background and objective: Adequate relief of pain after tonsillectomy is a common problem. We compared meperidine and tramadol when given at induction of anaesthesia with respect to their effects on postoperative pain relief and emergence characteristics after adenotonsillectomy in children.

Methods: Fifty children aged 4–7 yr undergoing tonsillectomy were randomly assigned to receive either tramadol 1 mg kg−1 (n = 25) or meperidine 1 mg kg−1 (n = 25) before commencement of the surgical procedure. Anaesthesia was induced with propofol (with cis-atracurium for muscle relaxation) and maintained with sevoflurane in oxygen and nitrous oxide. Postoperative pain was scored by a blinded observer using a facial pain scale in the recovery room at 0 (at arrival of the patient in the postoperative care unit) and at 10, 20 and 45 min thereafter. Agitation scores were also assessed by the same observer at 0 min. Heart rate and mean arterial pressure were recorded at regular intervals. The time to recovery to spontaneous respiration and the incidence of postoperative nausea and vomiting were noted.

Results: Facial pain scale scores were increased in the tramadol group at 0, 10 and 20 min (P < 0.05). No difference was observed in scores at the 45th min postoperation. Agitation scores were higher in the tramadol group than in the meperidine group. No statistical difference was found between the two groups. Heart rates and mean arterial pressures were similar in both groups. The time to recovery to spontaneous respiration was delayed with meperidine compared with tramadol (P < 0.05). The incidence of nausea and vomiting was not statistically different between groups.

Conclusions: Meperidine was more effective for pain relief and provides better emergence characteristics than tramadol after tonsillectomy in children.

Summary

Background and objective: We assessed the intraoperative haemodynamic responses and recovery profiles of total intravenous anaesthesia with remifentanil and alfentanil for outpatient surgery.

Methods: Patients in Group 1 (n = 20) received alfentanil 20 μg kg−1 followed by 2 μg kg−1 min−1 intravenously; patients in Group 2 (n = 20) received remifentanil 1 μg kg−1 followed by 0.5 μg kg−1 min−1 intravenously. Both groups then received propofol 2 mg kg−1 followed by 9 mg kg−1 h−1 intravenously. Five minutes after skin incision, infusion rates were decreased, and at the end of surgery, all infusions were discontinued. Early recovery was assessed by the Aldrete score, whereas intermediate recovery was assessed with the postanaesthetic discharge scoring system (PADS).

Results: Perioperative arterial pressure was similar in both groups; heart rate was lower in Group 2 (P < 0.05). The times to spontaneous and adequate respiration, response to verbal commands, extubation and times for Aldrete score ≥9 were shorter in Group 2 patients (P < 0.05). Pain scores were higher in Group 2 patients (P < 0.05). Overall times for postanaesthetic discharge scores ≥9 were similar.

Conclusions: Early recovery of patients after day surgery is significantly shorter after total intravenous anaesthesia with remifentanil compared with that with alfentanil but postoperative pain management must be planned ahead.

Summary

Background and objective: Although percutaneous nephrolithotomy has many advantages over open surgery, some endocrine and haemodynamic responses have been reported. However, the effects of anaesthetic agents on these responses have not previously been reported. This study compared the effects of sevoflurane and total intravenous anaesthesia using propofol and alfentanil on the haemodynamic and hormonal changes during percutaneous nephrolithotomy.

Methods: Forty-two ASA I–II patients aged between 15 and 65 yr were studied. Sevoflurane in Group S (21 patients) or TIVA in Group TIVA (21) was used for the maintenance of anaesthesia. Haemodynamic variables and serum concentrations of sodium and potassium were measured before, during and after the procedure. Arterial blood-gas status, plasma renin, aldosterone and adrenocorticotrophic hormone concentrations were measured before and during the procedure.

Results: Mean heart rate was lower during percutaneous nephrolithotomy in Group TIVA compared with Group S (P < 0.01). The mean systolic and diastolic arterial pressures were not different in both groups at any stage of measurement (P < 0.05). Plasma renin, aldosterone and adrenocorticotrophic hormone concentrations were increased during percutaneous nephrolithotomy in both groups, but the increase was greater in Group S (P < 0.05).

Conclusions: In the sevoflurane group, the concentrations of renin, aldosterone and adrenocorticotrophic hormone were significantly higher after 15 min of irrigation compared with the total intravenous anaesthesia group. Although the clinical significance of this difference was not clear, these changes should be considered in certain patient groups.

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.