Can virtual reality simulation prepare patients for an MRI experience?

INTRODUCTION: A Magnetic Resonance Imaging (MRI) examination is often described by patients as frightening and uncomfortable. To prepare patients for an MRI examination, this study explored the use of virtual reality (VR) simulation compared to a mock MRI scan (full-scale MRI machine replica, without internal magnets). METHODS: Twenty participants underwent a VR and a mock MRI scan. Ratings of anxiety and how comfortable and relaxed the participants felt were recorded at five touchpoints during and after each simulation. Post-simulation questionnaires were used to gather responses on the experience and preferences. RESULTS: No significant differences were found in participants' ratings of how anxious they felt during or between the two simulations (χ2 (9) = 27.269, p = .126), or how relaxed they felt (χ2 (9) = 14.664, p = .101). There were also no significant differences in the reported levels of comfort between the two types of simulation (χ2 (9) = 20.864, p = .013, post hoc tests for all VR versus mock scan rankings p > .05). There were no significant differences in how real the participants thought each simulation felt, or how anxious, relaxed, and comfortable they felt following each type of simulation (p > .05). Although 65% of participants thought the mock simulation felt more real than the VR, 86% found VR simulation to be a helpful way to prepare for a real MRI exam. CONCLUSION: VR could be a feasible and accessible alternative to mock scanning. It has the potential to improve patient experiences of potentially stressful MRI examinations. IMPLICATIONS FOR PRACTICE: VR offers clinicians a new cost-effective tool to prepare patients for an MRI examination. VR technology could be used at home, as a training tool, to familiarise clinicians and clinical trainees with the MRI procedure and better understand patients' experiences.

A comparison of the effects of ranitidine and omeprazole on volume and pH of gastric contents in elective surgical patients.

BACKGROUND AND OBJECTIVE: In cases of aspiration of gastric contents the risk of pneumonitis is dependent on the pH and volume of the gastric contents. Omeprazole and rantidine each decrease gastric volume and increase gastric pH. We evaluated the efficacy of preoperative administration of omeprazole (60 mg) or ranitidine (150 mg) in the prophylaxis of aspiration pneumonitis. METHODS: Data were obtained from 75 elective female surgical patients randomly allocated to one of three groups, who received either omeprazole 60 mg orally, or ranitidine 150 mg orally, or neither, on the evening prior to, and on the morning of, surgery. Gastric volume and pH was measured using blind aspiration. RESULTS: Both pH < 2.5 and volume > 25 mL were present in none of the patients in either the ranitidine or omeprazole groups, compared to 15 of 25 control patients (P < 0.0001). CONCLUSIONS: Preoperative oral administration of omeprazole (60 mg) or ranitidine (150 mg) reduced residual gastric content volume and increased pH > 2.5, possibly reducing the effects of pulmonary aspiration of gastric contents.

Ventilator-patient dyssynchrony induced by change in ventilation mode.

Patient-ventilator interactions may be coordinated (synchronous) or uncoordinated (dyssynchronous). Ventilator-patient dyssynchrony increases the work of breathing by imposing a respiratory muscle workload. Respiratory centre output responds to feedback from respiratory muscle loading. Mismatching of respiratory centre output and mechanical assistance results in dyssynchrony. We describe a case of severe patient-ventilator dyssynchrony and hypothesize that dyssynchrony was induced by a change in mode of ventilation from pressure-cycled to volume-cycled ventilation, due to both ventilator settings and by the patient's own respiratory centre adaptation to mechanical ventilation. The causes, management and clinical implications of dyssynchrony are discussed.

Delayed postoperative gastric emptying following intrathecal morphine and intrathecal bupivacaine.

PURPOSE: A decrease in the rate of gastric emptying can delay resumption of enteral feeding, alter bioavailability of orally administered drugs, and result in larger residual gastric volumes, increasing the risk of nausea and vomiting. We compared the effects of 1) intrathecal bupivacaine (17.5 mg) and 2) the combination of intrathecal morphine (0.6 mg) and intrathecal bupivacaine (17.5 mg) on the rate of gastric emptying in patients undergoing elective hip arthroplasty. METHODS: Twenty four fasting ASA 1-3 patients were randomly assigned, in a double blind manner, to receive intrathecal hyperbaric bupivacaine (17.5 mg), either alone (group 1), or followed by intrathecal morphine (0.6 mg) (group 2). Gastric emptying was measured (using an acetaminophen absorption technique), twice in each patient; preoperatively, and approximately one hour postoperatively. Gastric emptying parameters are: AUC (area under the plasma acetaminophen concentration time curve), maximum plasma acetaminophen concentration (Cmax), and time to Cmax (tCmax), analyzed using paired Student's t tests. RESULTS: Gastric emptying rates were reduced in both group 1 (AUC = 14.98 (3.8) and 11.05 (4.6) pre- and postoperatively, respectively) and group 2 (AUC = 13.93 (3.59) and 6.4 (3.42) pre- and postoperatively, respectively); the magnitude of the reduction was greater in group 2 [AUC (P = 0.04), Cmax (P = 0.05), tCmax (P = 0.13)]. CONCLUSION: The combination of intrathecal morphine (0.6 mg) and intrathecal bupivacaine (17.5 mg) delays gastric emptying postoperatively.