An adaptation of the objective structured clinical examination to a final year medical student course in anaesthesia and intensive care.

The Department of Anaesthesia and Intensive Care at the Chinese University of Hong Kong provides a 4 week course in our specialty for final year medical students. Our curriculum covers basic concepts in anaesthesia and intensive care, management of common medical emergencies and the safe performance of basic practical skills. For the last 4 years we have used an adaptation of the Objective Structured Clinical Examination to assess learning. Question stations included the use of manikins to assess practical skills, such as cardiopulmonary resuscitation and airway management, identification and description of the use of equipment and interpretation of clinical scenarios and investigations. We believe that our adaptation of the Objective Structural Clinical Examination is better than traditional methods of examination and it has allowed us to identify deficiencies in our teaching methods. The Objective Structured Clinical Examination has been well received by our students and is perceived by them to be a fair reflection of their level of knowledge and skill attainment during the course.

Recovery after propofol infusion anaesthesia in children: comparison with propofol, thiopentone or halothane induction followed by halothane maintenance.

We have compared the recovery profiles of 163 healthy Chinese children after general anaesthesia for minor surgical procedures. Patients were allocated randomly to receive one of four anaesthetic techniques: propofol infusion for induction and maintenance using a pharmacokinetic model-controlled syringe pump set initially at a target concentration of 8 micrograms ml-1 and then adjusted according to clinical requirements; propofol 2.5-3.5 mg kg-1, thiopentone 4-5 mg kg-1 or 2-3% halothane for induction of anaesthesia followed by 1-2% halothane for maintenance of anaesthesia. All patients breathed a mixture of 70% nitrous oxide in oxygen through a laryngeal mask airway and received an appropriate regional anaesthetic block. Recovery was assessed using the time to achieve full Steward score, open eyes on command, orientation and the time required to complete a simple puzzle. Recovery was slowest with the propofol infusion (mean 39.8 (SD 12.9) min when eyes opened on command). The recovery times were significantly shorter with the three other techniques (propofol bolus 21.9 (9.9) min, thiopentone 23.4 (11.3) min, halothane 20.1 (8.9) min), and the choice among these three methods had no significant influence on the recovery profile.

Comparison of 0.125% bupivacaine with 0.125% bupivacaine and clonidine as extradural analgesia in the first stage of labour.

We have studied 42 healthy parturients with singleton vertex pregnancies, who were in the first stage of labour and requesting extradural analgesia. They were allocated randomly in a double-blind fashion to receive either 0.125% bupivacaine plain or 0.125% bupivacaine with clonidine 120 micrograms. Efficacy of analgesia was evaluated using linear visual analogue scoring (VAS), sensory block was assessed using bilateral pinprick in the mid-clavicular line and sedation scored on a five-point scale. Maternal and fetal cardiovascular variables were measured every 2 min for 20 min, at 30 min and subsequently at 15-min intervals. The reduction in VAS was greater at all times in the bupivacaine-clonidine group (P < 0.01). The median (range) duration of analgesia was greater in the bupivacaine-clonidine group (114.5 (30-243) min) compared with the bupivacaine group (53 (30-100) min) (P < 0.001). Analgesia was associated with a reduction in arterial pressure in both groups, but there were no between-group differences. Maternal heart rate was less than baseline values at 30-90 min in the bupivacaine-clonidine group only. Sedation was greater in the bupivacaine-clonidine group, especially from 15 to 45 min (P < 0.01). There were no differences in fetal heart rate, mode of delivery or Apgar scores between the two groups.

Analgesia after caesarean section with intramuscular ketorolac or pethidine.

We compared, in a double-blind randomised study, intramuscular ketorolac 30 mg (n = 49) and intramuscular pethidine 75 mg (n = 51) for analgesia after elective caesarean section under general anaesthesia. Anaesthesia was induced with thiopentone and suxamethonium and maintained with atracurium, nitrous oxide and isoflurane. Intravenous fentanyl 100 micrograms was given after delivery of the neonate. In the recovery ward, patients who requested analgesia were allocated randomly to receive ketorolac 30 mg or pethidine 75 mg intramuscularly. Analgesia was assessed at intervals up to six hours, using a visual analogue scale and a four-point verbal scale, while duration of analgesia was taken as the time until the patient requested additional analgesia. There was no difference in the duration of analgesia between groups (Mann-Whitney test P = 0.27, Mantel-Haentszel test P = 0.17). Twenty-six patients in the ketorolac group and 17 patients in the pethidine group requested further analgesia by 90 minutes. However, four patients in the ketorolac group and six patients in the pethidine group requested no further analgesia within 24 hours. Pain VAS and overall assessment of analgesia was similar between groups, although more side-effects (nausea, dizziness) were noted in the pethidine group. Ketorolac 30 mg and pethidine 75 mg provided similar but variable quality of analgesia after caesarean section.

Cardiovascular effects of i.v. induction in children: comparison between propofol and thiopentone.

We have compared the haemodynamic responses to i.v. propofol 2.5 mg kg-1 with those to thiopentone 5.0 mg kg-1 in 41 healthy Chinese children at induction of anaesthesia. They were allocated to four groups according to their age and induction agent received: group 1 < 2 yr, propofol, n = 9; group II < 2 yr, thiopentone, n = 9; group III 2-12 yr, propofol, n = 12; group IV 2-12 yr, thiopentone, n = 11. Anaesthesia was maintained by spontaneous ventilation with 70% nitrous oxide and 0.5% halothane in oxygen. Arterial pressure and heart rate were monitored by automatic oscillotonometer. Stroke volume was measured by two-dimensional echocardiography and pulse Doppler. Measurements were made before induction and at 1-min intervals for 5 min after induction. The reduction in mean arterial pressure was significantly greater after propofol (28-31%) than after thiopentone (14-21%) (P = 0.001). The reduction in cardiac index (10-15%) after induction was not significantly different between the two agents (P = 0.122). Baroreflex mediated increases in heart rate and systemic vascular resistance were less after propofol than after thiopentone. The baroreceptor reflex was more attenuated in children aged less than 2 yr than in older children.

The minilink breathing system: resistance and suitability for spontaneous ventilation.

The Portex infant breathing/ventilation systems with 8.5 mm and 15 mm internal diameter connectors were compared with a standard T-piece which had a 15 mm connector and 22 mm internal diameter tubing. The differential pressures across each system were measured at constant fresh gas flows up to 30 l.min-1 dry air. Resistance was calculated at flows compatible with quiet respiration and peak inspiratory flow. Flow resistance of the 3.0 mm internal diameter tracheal tube in conjunction with the minilink breathing systems were similar to those previously reported for tracheal tubes alone. However, the minilink breathing system assumed a greater influence on resistance when tracheal tubes of larger internal diameter were used. It added considerably more resistance than the standard tubing. This may have a deleterious effect during spontaneous ventilation in older children.

Plasma catecholamines and neonatal condition after induction of anaesthesia with propofol or thiopentone at caesarean section.

Increased maternal sympathetic nervous system activity may decrease placental perfusion and cause adverse neonatal effects. We have studied the catecholamine response and neonatal outcome in Chinese patients with uncomplicated, singleton pregnancies undergoing Caesarean section. Anaesthesia was induced with thiopentone 4 mg kg-1 (n = 32) or propofol 2 mg kg-1 (n = 30) followed by suxamethonium. Laryngoscopy was performed after 1 min and tracheal intubation completed by 2 min. Anaesthesia was continued with atracurium, nitrous oxide and isoflurane. Maternal venous blood samples were taken at 0, 1, 2, 3, 4 min and at delivery for assay of catecholamines. The increase from baseline values in mean arterial pressure after tracheal intubation was greater in the thiopentone group (29 (SD 15) mm Hg) compared with the propofol group (18 (14) mm Hg) (P < 0.01). The concentrations of noradrenaline and adrenaline increased in both groups after tracheal intubation. Maximum noradrenaline concentrations were greater in the thiopentone group (413 (177) pg ml-1) compared with the propofol group (333 (108) pg ml-1) (P < 0.05), but there were no differences between groups in adrenaline concentrations. Neonatal Apgar scores, neurobehavioural testing and umbilical catecholamine, blood-gas tension and oxygen content analysis were similar between groups. Propofol attenuated the hypertensive and catecholamine response associated with laryngoscopy and tracheal intubation but there was no improvement in neonatal outcome.

Cardiac evaluation following heart injury.

Both penetrating and blunt cardiac injuries require urgent management. Delayed sequelae and complications have been reported to occur in 4 to 56% of survivors and frequently required secondary surgical corrections. Between January 1980 and June 1984, 204 patients presented with heart injuries. One hundred twenty-eight of these patients survived. Of the 90 undergoing cardiorrhaphy in the operating room, 78 survived. Two-dimensional (2-D) and pulsed-Doppler echocardiography (echo) and/or cardiac catheterization were performed in 40 patients for suspected significant residual injury. Eight of the 40 required secondary cardiac operations. Two-dimensional echo demonstrated pericardial effusion, abnormal chamber enlargement, abnormal cardiac wall motion, intracardiac missile, and intracardiac and pleural thrombus. Pulsed-Doppler findings included ventricular septal defect, tricuspid insufficiency and right ventricular turbulence secondary to arteriovenous fistulae. Cardiac catheterization detected lesions undetected by 2-D echo in one patient with a gunshot wound. It is concluded that in the absence of cardiac bullets seen on routine chest X-ray, 2-D with pulsed-Doppler echo is an excellent screening technique. With a positive echo study or a residual bullet overlying the cardiac silhouette, cardiac catheterization is indicated in selected patients.

Tricuspid regurgitation during pregnancy: two-dimensional and pulsed Doppler echocardiographic observations.

Although precordial murmurs occur frequently during pregnancy, their origin is rarely known. To investigate the nature of these murmurs, 2-dimensional (2-D) and pulsed Doppler echocardiography was performed in 81 asymptomatic pregnant women who had new systolic precordial murmurs. End-systolic right atrial dimensions, early diastolic tricuspid anular diameters, and end-diastolic right ventricular diameters were measured from the apical 4-chamber view and compared with measurements from 26 young nonpregnant women without known heart disease. Tricuspid regurgitation (TR) was detected by pulsed Doppler echocardiography in 35 of 81 pregnant women. Thirty-two pregnant women had normal 2-dimensional and pulsed Doppler echocardiographic findings. Other valvular or congenital lesions were detected in 14 pregnant women. The right-sided intracardiac diameters were larger in all groups of pregnant women than in non-pregnant control subjects (p less than 0.001). The tricuspid anular diameter was larger in the pregnant women with TR than in pregnant women with normal pulsed Doppler echocardiographic findings (24 +/- 2 vs 22 +/- 3 mm, p less than 0.015). No patient had clinical difficulty associated with a murmur. Functional TR, therefore, often occurs in pregnancy and appears to be a result of dilation of the tricuspid anulus. TR may contribute to the development of murmurs in pregnant women.

Gonococcal endocarditis: a case series demonstrating modern presentation of an old disease.

Gonococcal endocarditis appeared with striking frequency in the preantibiotic era compared with its surprising rarity today. We present a series of four episodes of gonococcal endocarditis, which presented to our institution in the last 2 years, after no cases in the previous decade. Three episodes involved the aortic valve and required emergency aortic valve replacement. One episode involved the tricuspid valve and was successfully cured with antibiotic infusion alone. Combining our four patients with the available 25 well-documented gonococcal endocarditis cases reported in the English medical literature during the antibiotic era, we demonstrated that the disease incidence may be increasing, that infections more often involve left-sided cardiac structures (particularly the aortic valve), and that the association with a quotidian fever curve, rash and arthritis, and overt gonococcal infection is less common than previously reported. These patients frequently present with fulminant and dramatic valvular insufficiency without immediately positive blood cultures and complete echocardiographic evaluation seems to provide a valuable aid in making a presumptive diagnosis of endocarditis and directing appropriate clinical management.

Acute renal failure associated with indomethacin administration.

Two patients had transient deterioration of renal function during acute infectious states while receiving indomethacin. Neither patient was in septic shock; renal function deteriorated at a time when clinically the infection was improving and both patients improved when indomethacin was discontinued, with return of renal function to baseline. Indomethacin inhibits prostaglandin synthesis and has been shown to reduce glomerular filtration and alter renal hemodynamic autoregulation. In susceptible patients these effects may be clinically significant. Careful monitoring of renal function in such patients requiring indomethacin therapy is warranted.