Comparison of the re-usable LMA Classic and two single-use laryngeal masks (LMA Unique and SoftSeal) in airway management by novice personnel.

In a single-blind randomized trial, three types of laryngeal masks: the reusable LMA Classic, the single-use LMA Unique and SoftSeal were inserted by novice medical officers in anaesthesia. Five successive attempts were undertaken with each mask type. The order of the mask type insertion was randomly selected. Mean (SD) insertion times for LMA Classic, LMA Unique and Soft Seal were 32.9 (12.3), 39.6 (23.4) and 49.4 (50.4) seconds respectively. Differences were only significant between LMA Classic and SoftSeal (P=0.012). There were no significant differences in first attempt success rates (LMA Classic 80%, LMA Unique 77% and SoftSeal 62%). The SoftSeal was most frequently associated with blood on the mask (32%) compared to the LMA Unique (9%) and LMA Classic (6%). Sore throat was experienced in 14% of patients in the LMA Unique group versus 41% and 42% in the LMA Classic and SoftSeal groups respectively. Mean +/- SD oropharyngeal leak pressure was significantly higher in the SoftSeal (21+/-6 cmH2O) compared to the LMA Classic (17+/-7 cmH2O) and LMA Unique (16+/-6 cmH2O). Novice medical doctors can be taught to insert disposable laryngeal masks. The SoftSeal took longer to insert, which resulted in a higher incidence of blood on the mask, but success rates did not differ The LMA Unique was associated with the lowest incidence of sore throat in the immediate postoperative period. A higher oropharyngeal leak pressure with the SoftSeal may indicate improved airway seal and protection against aspiration.

Recovery following tonsillectomy a comparison between tramadol and morphine for analgesia.

BACKGROUND: The optimal method of intraoperative analgesia for adult tonsillectomy is uncertain. It is important that recovery should be rapid so that the airway is not compromised. Tramadol hydrochloride is an analgesic with mixed -mu and non-opioid activities which has less respiratory depression effects compared to morphine. PATIENTS AND METHODS: We compared the recovery characteristics of patients undergoing tonsillectomy after they were given either morphine or tramadol for intra-operative analgesia. Seventy-nine ASA (American Society of Anesthesiologists) I patients were randomised to receive either tramadol 1.5 mg/kg (n = 44) or morphine 0.1 mg/kg (n = 35). A standard propofol-desflurane based general anaesthetic technique was used. RESULTS: Patients given tramadol recovered faster compared to morphine as demonstrated by the earlier eye opening at reversal (mean +/- SD, 4.7 +/- 1.5 min versus 5.6 +/- 1.8 min, p = 0.04). There was also significantly less nausea and vomiting in the patients given tramadol as compared to those given morphine (6.8% versus 28.6%, p = 0.01). There were no other clinically important adverse effects in either group. CONCLUSION: We conclude that tramadol given for intra-operative analgesia during tonsillectomy results in faster recovery with significantly less nausea and vomiting in the early postoperative period.

Cardiopulmonary bypass is not associated with increased jugular venous blood free radical activity.

We have measured jugular venous oxygen saturation (sjv(O2)) and lactate, arterial and jugular venous blood levels of lipid peroxidation products--malondialdehyde (MDA) and diene conjugates as an index of free radical activity in eight adults undergoing coronary artery bypass surgery. Measurements were carried out at six specific times: T1--within 5 min before cardiopulmonary bypass (CPB), T2--within the first minute after the commencement of CPB, T3--during stable temperature (28 degrees C) on CPB, T4--during rewarming at 34 degrees C, T5--15 min after CPB and T6--at skin closure. There were no significant changes in arterial, jugular venous and arterio-jugular venous (a-jv) differences in diene conjugates and MDA. There was no correlation between sjv(O2), lactate and a-jv differences in MDA and diene conjugates. These results are not indicative of ischaemia-reperfusion injury across the cerebral circulation during hypothermic CPB.

Remifentanil in the management of laparoscopic resection of phaeochromocytoma--case reports.

INTRODUCTION: The laparoscopic adrenalectomy approach to phaeochromocytoma surgery offers the opportunity to use new short-acting drugs to facilitate rapid recovery. CLINICAL PICTURE: We report on 2 cases who underwent laparoscopic resection of phaeochromocytoma. The first was a 40-year-old lady who had been started on phenoxybenzamine 20 mg bd, but developed a recurrence of bronchial asthma after starting atenolol which was subsequently stopped. The second was a 51-year-old lady with neurofibromatosis who was taking phenoxybenzamine 20 mg bd and propanolol 20 mg tds. TREATMENT: The intraoperative management was facilitated by the stress suppressive effects of remifentanil infusion combined with nitroprusside as a vasodilator, and desflurane as an anaesthetic. OUTCOME: Both patients were extubated at the end of surgery and made uneventful recovery. CONCLUSION: Remifentanil possesses several useful properties, which deserve serious consideration in phaeochromocytoma surgery, particularly in the instance where beta-blockade is contraindicated. In combination with other titratable short-acting agents, it potentially facilitates rapid recovery especially following the laparoscopic approach to adrenalectomy.

Audit of total parenteral nutrition in an adult surgical intensive care.

INTRODUCTION: A preliminary one-year review of total parenteral nutrition (TPN) in the adult surgical intensive care unit (SICU) in view of its complications, cost and lack of consistent benefits in the critically ill. MATERIALS AND METHODS: All the case records of patients receiving TPN in the SICU starting from first January to end December 1998 were studied. RESULTS: Fifty patients received TPN during the study period. Four case records were unavailable. The indications for starting TPN were comparable with those set up by the Stanford University Hospital. Sepsis with gastrointestinal failure at 30.5% [95% CI, 17.7% to 45.8%] was one of the major indicators for TPN use and also the biggest contributor to mortality (50%) [95% CI, 35% to 65%]. Hyperglycaemia and line sepsis increased with duration of TPN use. Pneumonia, bacteraemia and wound infection peaked by the second week. Patients receiving TPN for inadequate and delayed enteral feeding fared better with 45.8% survival [95% CI, 30.9% to 61%]. None of the patients with polytrauma or malignancy cachexia died. 52.2% [95% CI, 37% to 67.1%] survived to be discharged from hospital. Caloric requirements were calculated using Harris-Benedect's equation and estimated using 30 to 35 kcal/kg/day. 64.3% were overfed and 50% received excessive non-protein calorie-to-nitrogen ratio. Ninety-eight per cent and 81% received less than the recommended amino-acid and glucose, respectively. Fifty-eight per cent received adequate lipids. CONCLUSION: This audit highlights the shortcomings in TPN prescription and characteristics of the attendant complications. Efforts must be directed towards encouraging uniformity and level of practice standards.

Tracheal intubation by novice staff: the direct vision laryngoscope or the lighted stylet (Trachlight)?

OBJECTIVE: To compare the ease of use of the direct vision laryngoscope and the lighted stylet (Trachlight) by novice staff. METHODS: Ten novice medical officers (MOs) performed orotracheal intubations using either the conventional direct vision laryngoscope (DL) or a lighted stylet device (Trachlight). They performed their DL intubations during the first phase of the study, followed by the Trachlight intubations in the subsequent phase. RESULTS: 51 of 54 (94%) of the DL intubation attempts were successful compared with 36 of 54 (67%) of the Trachlight intubations (p<0.001). The mean (SEM) time for intubation was 44 (7) seconds in the DL group and 66 (13) seconds in the Trachlight group (p=0.004). In addition 45 of 54 (83%) of the DL intubations were successful at the first attempt versus 15 of 54 (28%) in the Trachlight group (p<0.001). CONCLUSION: The results show that the use of the conventional direct vision laryngoscope in novices is associated with significantly shorter mean intubation times and higher success rates on the first attempt compared with the Trachlight.

The modified Cormack-Lehane score for the grading of direct laryngoscopy: evaluation in the Asian population.

The use of a modified Cormack-Lehane scoring system (MCLS) of laryngoscopic views, as previously introduced in the Western population, was investigated during direct laryngoscopy in the Asian population. We studied the distribution of the different grades of MCLS, the predictive factors and rate of difficult laryngoscopy, and the association with difficult intubation. Six hundred and five patients requiring tracheal intubation during general anaesthesia were prospectively studied. The optimal views during direct laryngoscopy were scored using the 5-grade MCLS system. The distribution of the laryngoscopy scores was 73.9% Grade 1 (full view of the vocal cords), 21.0% Grade 2A (partial view of the vocal cords), 3.3% Grade 2B (only the arytenoids and epiglottis seen), 1.6% Grade 3 (only epiglottis visible) and 0.2% Grade 4 (neither the epiglottis nor glottis seen). External laryngeal pressure was necessary in 45.3% of cases to optimize laryngoscopic views. Grade 2B was associated with significantly higher incidence of difficult intubation compared with Grade 2A (65% vs 13.4%). The rates of difficult laryngoscopy and intubation were 5.1% and 6.9% respectively. The Mallampati classification and thyromental distance were associated with low predictive value for difficult laryngoscopy. The MCLS better delineates the difficulty experienced during laryngoscopy than the original Cormack-Lehane grading

Vibrio vulnificus septicaemia.

Vibrio vulnificus is an opportunistic pathogen capable of causing a fulminant septicaemia in susceptible patients. Underlying chronic diseases such as liver impairment and immunosuppression are important factors contributing to the severity of the infection and outcome. Early suspicion and diagnosis with appropriate antibiotic therapy is important as delay can adversely affect outcome. For those who develop tissue necrotizing fasciitis, early surgical debridement is recommended to allow better penetration of antibiotics and also to reduce the severity of the septicaemia. Mortality is quoted as between 50% and 90%. Current antibiotic recommendations are intravenous ceftazidime 2 g tds and doxycycline 100 mg od.

Perioperative management of a patient with congenital myasthenia gravis for elective caesarean section.

Congenital disorders of neuromuscular transmission are commonly referred to as congenital myasthenia gravis because of their clinical similarity to the immune-mediated disease. Differentiation between the immune-mediated and congenital forms of the disease is important, because therapy established for the former may not be appropriate for patients with the latter presentation. The course of this rare neuromuscular disorder during pregnancy and its influence on anaesthesia remain largely unknown. We report on the case of a 32-year-old parturient suffering from congenital myasthenia gravis scheduled for elective caesarean section. The perioperative management of this patient who underwent the operation under spinal anaesthesia was reviewed. The effects of anaesthetic agents and techniques on the course of congenital myasthenic patients may need further review in the light of latest findings in the electrophysiology, genetic and therapeutic studies of this syndrome.

Clinical evaluation of the Mapleson theoretical ideal fresh gas flow sequence at the start of low-flow anaesthesia with isoflurane, sevoflurane and desflurane.

Mapleson used a computer spreadsheet model to predict the theoretical ideal fresh gas flow sequence at the start of low-flow anaesthesia. The aim was to increase the end-expired partial pressure of inhalational agent (PE'an) to one minimum alveolar concentration (MAC) as quickly as practicable and then to keep it constant. Ninety adult patients undergoing elective tonsillectomy under general anaesthesia were randomly allocated to one of three groups (n = 30) to receive isoflurane, sevoflurane or desflurane in oxygen. Fresh gas flow and vaporiser settings as specified by Mapleson were followed in all cases except that the maximum setting for desflurane was 18% (2.7 MAC instead of 3 MAC). Recordings of PE'an were made at 1, 2, 3, 4, 5, 7, 10, 15 and 20 min. Mean values of PE'an exceeded 1 MAC by 2 min in all three groups and remained above this value throughout. Each group's PE'an measurements were divided by their respective 1-MAC value. A simple two-level model (with patients at level 2 and time at level 1), with measurements at 1 min excluded, showed that the fitted value at 2 min and the time-weighted mean for 2-20 min for PE'iso (1.042 [95% CI 0.980-1.104] and 1.044 [0.984-1.104], respectively) were not significantly different from its 1-MAC value, whereas those of the PE'sevo (1.169 [1.119-1.219] and 1.143 [1.119-1.219]) and PE'des (1.305 [1.261-1.349] and 1.140 [1.098-1.182]) were significantly higher than their respective 1-MAC values. The Mapleson concept of an initial high fresh gas flow and high vaporiser settings, followed first by reduced high fresh gas flow, as followed in this clinical study, results in PE'an values close to or slightly higher than predicted in the spreadsheet model.

Intravenous opioids reduce airway irritation during induction of anaesthesia with desflurane in adults.

Desflurane is not used for the induction of anaesthesia despite its favourable pharmacokinetic characteristics because it causes airway irritation. We investigated whether pretreatment with i.v. narcotics reduced unwanted effects. One hundred and eighty adults were randomized to three groups (60 per group) to receive i.v. saline, fentanyl 1 microgram kg-1 and morphine 0.1 mg kg-1, respectively, before inhalational induction with desflurane in nitrous oxide and oxygen. Mean time to loss of response to commands was 4.0 min, without significant differences between groups. The incidence of coughing was greater (25%) in the control group than in the fentanyl (5.0%) and morphine groups (8.3%). The incidence of apnoea was 20.0% in the control group versus 13.3 and 5.0% in the fentanyl and morphine groups, respectively. Laryngospasm developed in 11.7% of controls compared with 3.3 and 1.7% in the fentanyl and morphine groups, respectively. More patients in the control group had excitatory movements (46.7%) than in the fentanyl (16.7%) and morphine (8.3%) groups. These results demonstrate that i.v. opioids reduce airway irritability significantly during inhalational induction with desflurane in adults.

The predictive value of intraoperative ST-segment monitoring as a marker of myocardial injury.

AIM: To evaluate the usefulness of dynamic intraoperative ST-monitoring in high-risk patients comparing it to preoperative clinical assessment and concurrent biochemical markers of cardiac injury. MATERIALS AND METHODS: Twenty-three patients clinically assessed as being at high risk for perioperative cardiac complications were recruited into this prospective, observational study in a public hospital. All had serial ECGs, cardiac enzymes and troponin-T measurements. The sensitivity, specificity, positive and negative predictive value of ST-segment changes in terms of predicting cardiac complications were calculated. We investigated the relationship between ST changes and biochemical markers of ischaemia and the predictive value of nonspecific (ASA) and specific (Goldman) clinical scores for cardiac complications. RESULTS: When correlated with cardiac complications, ST-segment monitoring had sensitivity 45.4%, specificity 100%, positive predictive value 100% and negative predictive value 66.7%. The correlation with CK-MB and troponin T was sensitivity 16.7% and 25%, specificity 73.3% and 75%, positive predictive value 20% and 20%, and negative predictive value 68.8% and 80%, respectively. The percentage of patients with cardiac complications increased with poor Goldman and ASA clinical scores; 25%, 40%, 62.5% and 100% in Goldman risk index groups of 0-5, 6-12, 13-25 and > 25, respectively; and 33.3% and 52.6% in ASA II and ASA III, respectively. CONCLUSIONS: This study demonstrates the importance of the anaesthesiologist preoperative assessment of cardiac risk. The probability that a patient with significant ST-depression will develop subsequent cardiac complications is 100%, which reflects its usefulness in this high-risk pre-selected sample. However, the test has a low sensitivity (45.4%).

Effects of temperature strategy during cardiopulmonary bypass on cerebral oxygen balance.

BACKGROUND: Cerebral injury is the most serious complication of cardiopulmonary perfusion (CPB). With the advent of warm heart surgery, the effect of temperature strategy during perfusion and its effect on cerebral oxygen balance needs further study. METHODS: Three groups of patients (n=8, each) undergoing coronary artery bypass graft (CABG) surgery were studied. Group H, M and N underwent CPB at 28 degrees C, 32 degrees C and normothermia (>36 degrees C), respectively. The extracorporeal circuit was primed with Hartmann's solution 2.5 l and flow of 1.8 l min(-1) m(-2) at 28 degrees C, and 2.4 1 min-1 m(-2) at 32 degrees C and normothermia. All patients had a 4F oximetry catheter (Opticath, Oximetrix, Abbott Laboratories) inserted in the right jugular bulb for continuous measurement of jugular venous oxygen saturation (sjvO2). Data was collected at six specific times: T1- within 5 min before initiation of CPB, T2 - within the first minute after CPB, T3 - during stable temperature on CPB (28 degrees C, 32 degrees C, >36 degrees C), T4 - during rewarming at 34 degrees C in groups H and M, 15 min before coming off CPB in group N, T5 - 15 min after CPB, T6 - skin closure. At each time mean arterial pressure (MAP) and sjvO2 were recorded. Arterial blood and jugular venous blood were sampled for measurement of arterial oxygen saturation (saO2) and jugular venous lactate (sjv(lactate)), respectively. RESULTS: SjvO2 values decreased at times T2, T3 and T4 when compared to baseline (p<0.05) but there were no significant group differences at any time. Cerebral arteriovenous oxygen saturation (a-jvO2) differences mirrored sjvO2 changes. Sjv(lactate) values increased from baseline following CPB but fell consistently with time - there were no significant group differences at each time point. SjvO2 and a-jvO2 values were not significantly correlated with sjv(lactate). CONCLUSION: During pump flows employed in this study, cerebral oxygen balance and perfusion appear unaffected by temperature.

Fibre-optic aided bougie (FAB) for simulated difficult tracheal intubation.

INTRODUCTION: Difficult intubation remains a key problem and the value of the gum elastic bougie as a first approach is well recognised. MATERIALS AND METHODS: A fine fibre-optic endoscope (Rapiscope, Cook Critical Care) was used in 50 patients to verify placement of a custom-designed hollow plastic bougie prior to "rail-roading" a tracheal tube. Following induction and muscle relaxation, direct laryngoscopy was performed after two-minutes of assisted ventilation. The laryngoscope blade was lowered to simulate difficult intubation and the bougie passed behind the epiglottis. The position of the introducer bougie was then checked using the Rapiscope. Following correct bronchoscopic identification of the tracheobronchial anatomy, a tracheal tube was then "rail-roaded" following withdrawal of the scope. RESULTS: All patients were successfully intubated following identification of the bronchial tree by the Rapiscope: three on the second attempt and the rest on the first. Mean (SD, range) time to successful bronchoscopic confirmation of correct placement of the bougie was 38 s (9.1 s, 19 to 60 s). All bronchoscopic assisted intubation were subsequently confirmed by capnography after tracheal tube insertion. Mean (SD, range) time to successful intubation was 106 s (14 s, 52 to 132 s). CONCLUSION: The fibre-optic assisted bougie (FAB) offers a promising technique in patients who may be difficult to intubate but who can be ventilated. Further developments are required to achieve a faster intubation time but oxygenation may be achieved by jetting down the hollow bougie.

Combined high-frequency ventilation (CHFV) in the treatment of acute lung injury--a case report.

A 22-year-old man was admitted to a district general hospital with chest injuries, a ruptured spleen and limb fractures, sustained in a road traffic accident. After an emergency splenectomy, the patient developed unilateral pulmonary oedema with hypoxaemia which was resistant to both conventional controlled mechanical ventilation (CMV) and independent lung ventilation (ILV). He was transferred to a specialist cardiothoracic unit where high frequency jet ventilation (HFJV) also failed to achieve adequate oxygenation. Combined high frequency ventilation (CHFV), using high frequency pulses from a Bromsgrove Penlon Jet ventilator superimposed onto small tidal volumes from an Engstrom Erica improved oxygenation rapidly to allow decreases in inspired oxygen fraction (FiO2), peak airway pressure (PAWP) and positive end expiratory pressure (PEEP). Progressive weaning from ventilatory support was then possible over five days. CHFV is a valuable technique in the treatment of acute catastrophic lung injury and needs wider recognition.