Educational psychology in medical learning: a randomised controlled trial of two aide memoires for the recall of causes of electromechanical dissociation.

OBJECTIVES: Although mnemonics are commonly used in medical education there are few data on their effectiveness. A RCT was undertaken to test the hypothesis that a new aide memoire, "EMD-aide", would be superior to the conventional "4Hs+4Ts" mnemonic in facilitating recall of causes of electromechanical dissociation (EMD) among house officers. METHOD: "EMD-aide", organises causes of EMD by frequency of occurrence and ease of reversibility: four groups organised by shape, colour, position, numbering, clockwise sequence, and use of arrows. Eight hospitals were randomised in a controlled trial and 149 house officers were then recruited by telephone. Baseline ability to recall causes of EMD was recorded at one minute and overall. House officers were then sent a copy of either "4Hs+4Ts" or "EMD-aide" according to randomisation group. Recall ability was retested at one month. RESULTS: 68 of 80 and 51 of 69 house officers completed the study in the "4Hs+4Ts" and "EMD-aide" groups respectively (NS) with similar baseline recall. After intervention median number of recalled causes was greater in the "EMD-aide" group, eight compared with seven at one minute (p = 0.034) and eight compared with seven overall, p = 0.067. Recall of all eight causes was more common in "EMD-aide" group, 54% compared with 35%, p = 0.054, and these house officers spent longer examining their aide memoire, p<0.001. CONCLUSIONS: "EMD-aide" may be superior to "4Hs+4Ts" in facilitating the recall of the causes of electromechanical dissociation. Educational psychology of medical learning and the use of aide memoires in general are worthy of further study.

Survey of abuse and violence by patients and relatives towards intensive care staff.

A postal survey of senior nurses in intensive care units in England and Wales was conducted. The aim was to ascertain the frequency of abusive and violent behaviour by patients and relatives towards intensive care staff, discover the perceived causes, effects and documentation of such behaviour and define the current and proposed security arrangements for intensive care units. Response rate was 94%. During the study period, verbal abuse of nurses by patients and by relatives occurred in 87% and 74% of intensive care units, respectively. The relevant figures for doctors were 65% and 59%, respectively. Nurses experienced physical abuse by patients and by relatives in at least 77% and 17% of intensive care units, respectively (doctors 38% and 8%). Illness was the main perceived cause of offences by patients whereas 'distress' (45%), alcohol (24%), sociopathic behaviour (27%) were the main putative causes amongst relatives. Whilst 43% of intensive care units have no security system at the door, staff awareness, training and communication skills may be the principle tools in reducing the frequency and consequences of violent and abusive behaviour. This survey probably underestimates the problem.

Nasopharyngeal oxygen therapy produces positive end-expiratory pressure in infants.

UNLABELLED: The World Health Organisation recommends nasopharyngeal catheters as a safe and efficient method of oxygen administration in infants. However, little is known about the mechanisms of the improvement in oxygenation. The aim of the present study was to determine whether nasopharyngeal oxygen therapy produces positive end-expiratory pressure (PEEP). Nine spontaneously breathing infants (median age 13 months, range 10 days to 20 months) after heart surgery were investigated. All patients had normal pulmonary blood flow at the time of the study (Qp:Qs=1:1). Oxygen (oxygen fraction 1.0) was delivered by an 8 F catheter inserted into the nasopharynx (tip just visible below the soft palate). The pulmonary mechanics were analysed using a single compartment model of the respiratory system. Oesophageal pressure (Pes) at end-expiration, dynamic lung compliance (C(L)) and resistance (R(L)), minute ventilation, PaCO2 and PaO2 were measured at baseline without a nasopharyngeal catheter or oxygen, and at oxygen flows of 0.5 l/min, 1.0 l/min and 2.0 l/min. All the flows generated significant increases in PEEP. Mean difference in PEEP (SD, paired t-test versus baseline): 1.6 cm H2O (1.4, P=0.008) with 0.5 l/min of oxygen; 2.8 cm H2O (2.7, P=0.014) with 1.0 l/min of oxygen; and 4.0 cm H2O (2.9, P = 0.004) with 2.0 l/min of oxygen. There was a significant correlation between all the nasopharyngeal flows (in ml/kg per min) and the generated PEEP (P<0.001) and between the C(L) values and the generated PEEP (P < 0.05). There was no significant difference in PaCO2 and R(L). Minute ventilation was significantly less with nasopharyngeal oxygen than at baseline. As expected, PaO2 increased significantly with increasing oxygen flows. CONCLUSION: Administration of oxygen through an 8 F nasopharyngeal catheter at flow rates recommended by the World Health Organisation (0.5 l/min in newborns, 1.0 l/min in infants) produces moderate amounts of positive end-expiratory pressure. The levels achieved may contribute to an improvement in oxygenation by altering the visco-elastic properties of the lung.

Psychological adjunct to perioperative antiemesis.

In a prospective, randomized study, we have examined the effects of preoperative and preinduction positive suggestion on postoperative emetic sequelae. A total of 226 patients were allocated randomly to receive either positive suggestions or no suggestions. Those patients in the positive suggestion group were told before operation and on induction of anaesthesia that postoperative emetic sequelae would be greatly reduced by the use of two antiemetic drugs. Control patients were simply asked to participate in a study of postoperative well being with no mention of nausea or vomiting. Nausea, vomiting or retching, and antiemetic administration were measured in the first 24 h after operation. Antiemetic administration in the positive suggestion group was 16.5% less than in the control group (P = 0.03) but there was no significant difference between the groups in nausea or vomiting-retching.

Fatal carbon dioxide embolism and severe haemorrhage during laparoscopic salpingectomy.

We report a case of fatal carbon dioxide embolism and severe haemorrhage during laparoscopic salpingectomy. A sudden decrease in end-tidal carbon dioxide concentration occurred after 1 h of operating time which, together with the clinical signs, suggested carbon dioxide embolism. Haemorrhage after pelvic venous injury was first noted after deflation of the pneumoperitoneum and resulted in potentiation of the adverse haemodynamic effects of massive gas embolism. Minimally invasive surgery involves more extensive tissue trauma and an increased duration of pneumoperitoneum compared with diagnostic laparoscopy and may increase the risk of serious complications.