Ondansetron, metoclopramid, dexamethason, and their combinations compared for the prevention of postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy: a prospective randomized study

BACKGROUND

A prospective randomized study was performed to assess the value of some individual risk factors for postoperative nausea and vomiting (PONV), and to compare the efficacy of ondansetron, metoclopramide, dexamethason, and combinations of these antiemetics in preventing PONV in patients after laparoscopic cholecystectomy.

METHODS

The study enrolled 210 patients (157 women and 53 men) scheduled for laparoscopic cholecystectomy. The patients were randomly divided into seven groups. In groups 1 to 6, antiemetic drugs were administered. Group 7, the control group, received no antiemetic. For all the patients, individual risk factors for the incidence of nausea also were analyzed. Both nausea and vomiting were assessed separately 1, 4, 8, and 12 h after the procedure.

RESULTS

Postoperative nausea and vomiting were significantly less frequent in menopausal women and more frequent in patients with a history of motion sickness. A comparison of mean values for the incidence of nausea and vomiting in groups 1 to 6 with the same values in group 7 showed that the mean PONV incidences were highest in groups 3 and 7, and the difference was significant.

CONCLUSIONS

Administration of antiemetic drugs significantly decreases the incidence of PONV in patients after laparoscopic cholecystectomy. The best decreases were achieved when ondansetron and dexamethason were applied together.

Modeling postural instability with Galvanic vestibular stimulation

In this study the effect of a pseudorandom binaural bipolar Galvanic stimulus generated by a sum of nonharmonically related sine waves on postural control was functionally assessed using computerized dynamic posturography (CDP), and the results compared to vestibulopathic patient populations and astronauts exposed to microgravity. The standardized CDP test battery comprised six sensory organization tests (SOTs) that combined three visual conditions (eyes open, eyes closed, and sway-referenced vision) with two proprioceptive conditions (fixed and sway-referenced support surfaces). Subjects (12) performed 18 randomized trials (three trials of each of the six SOTs) as a baseline, repeated the 18 trials with Galvanic vestibular stimulation (GVS), and then performed a post-GVS baseline. A 10 min rest period was inserted between each test battery. Anterioposterior postural sway increased significantly and was in the abnormal range (fifth percentile) during GVS for SOTs where visual input was compromised (sway-referenced surround) or absent. Postural stability returned to baseline when GVS was removed. An analysis of sensory input scores (somatosensory, visual, and vestibular) demonstrated the specificity of GVS in distorting vestibular input to postural control. The SOT scores observed in astronauts on landing day did not differ significantly to that generated by GVS in our normal subjects. GVS also induced a similar pattern of instability on CDP as profound bilateral vestibular loss, although not as severe. The results suggest that unpredictably varying GVS quantitatively and qualitatively models postural instability of vestibular origin.

Antiemetic activity of FK1052, a 5-HT3- and 5-HT4-receptor antagonist, in Suncus murinus and ferrets

We investigated the effect of FK1052 [(+)-8,9-dihydro-10-methyl-7-[(5-methyl-1H-imidazol-4-yl)methyl]pyrido[1,2-a]indol-6(7H)-one hydrochloride], a 5-HT3- and 5-HT4-receptor antagonist, on the emesis induced by motion stimuli, copper sulfate, or cisplatin in either Suncus murinus or ferrets and also clarified the role of the 5-HT3 and 5-HT4 receptors in these models. In Suncus murinus, oral administration of FK1052 (100 microg/kg) completely prevented emesis induced by cisplatin (18 mg/kg, i.p.). Intraperitoneal injection of scopolamine (10 mg/kg) and promethazine (32 mg/kg), but not FK1052 (1 mg/kg), significantly reduced the emetic responses by motion stimuli. In ferrets, copper sulfate (40 mg/kg, p.o.)-induced emesis was moderately prevented by FK1052 (3.2 mg/kg), but not by granisetron (3.2 mg/kg). Cisplatin-induced acute (10 mg/kg, i.v.) and delayed (5 mg/kg, i.p.) emesis were significantly reduced by single and multiple intravenous injection of both FK1052 (3.2 mg/kg) and granisetron (3.2 mg/kg), respectively. The present study suggests that FK1052 may be useful against both acute and delayed emesis induced by cancer chemotherapy. Moreover, it is suggested that blockades of 5-HT3 and 5-HT4 receptors are not relevant to the control of motion sickness; and furthermore, it suggested that blocking 5-HT4 receptors in addition to 5-HT3 receptors does not have an additional effect on the control of cisplatin-induced emesis, but that 5-HT4 receptors are at least partly involved in the mechanism of emesis induced by copper sulfate.

Health risks to air travelers

With focused pretravel counseling and intervention, travelers can be prepared to avoid many risks of in-flight problems. Travel medicine practitioners can include appropriate guidance for in-flight health and safety in discussions during pretravel visits.

A Comparison of Patients??? and Health Care Professionals??? Preferences for Symptoms During Immediate Postoperative Recovery and the Management of Postoperative Nausea and Vomiting

In this study we sought to examine the differences in patients' and health care professionals' preferences for symptoms during immediate postoperative recovery and the management of postoperative nausea and vomiting (PONV). The key differences between symptoms during immediate postoperative recovery (PONV, sedation, and pain) and management of PONV (prophylaxis, efficacy of antiemetic, and extra cost) were used to develop 14 scenarios in a questionnaire. Fifty-two health care professionals (anesthesiologists and recovery room nurses) and 200 women undergoing elective gynecological surgery were recruited (overall response rate, 97%). From patients' and health care professionals' perspectives, conjoint analysis showed that the most important attribute for immediate postoperative recovery was a reduction in the risk of PONV. Health care professionals placed more importance on postoperative sedation than patients did. They were more concerned about the cost of the antiemetic to the patient than the patients were themselves. There was no preference for a policy of effective treatment versus routine prophylaxis. This study shows that there were small differences in the importance of pain, sedation, efficacy of the antiemetic, and extra cost of treatment between patients and health care professionals.

Patient expectation is a strong predictor of severe nausea after chemotherapy

BACKGROUND

Patients may use their past experiences with nausea, as well as information about the incidence of nausea from chemotherapy that other patients have experienced, to form a prediction, or response expectancy, of nausea from their own upcoming chemotherapy. Mounting evidence suggests that these expectancies relating to nausea are significant predictors, and, likely, contributing factors to the development of treatment-related nausea.

METHODS

The patients in the current study were participants in the control arm of a multicenter clinical trial conducted between November 1999 and July 2001 by the University of Rochester Community Clinical Oncology Program. All patients in the current report were age >/= 18 years and were about to begin a first cancer treatment regimen containing doxorubicin.

RESULTS

Expectancy of nausea assessed before patients received their first doxorubicin-based chemotherapy treatment was found to be a strong predictor of subsequent nausea and in fact was stronger than previously reported predictive factors, including age, nausea during pregnancy, and susceptibility to motion sickness. Women who believed it was "very likely" that they would have severe nausea from chemotherapy were five times more likely to experience severe nausea than fellow patients who thought its occurrence would be "very unlikely."

CONCLUSIONS

Further studies confirming an expectancy of nausea as a risk factor are warranted as are studies examining the benefit to a patient's quality of life from modifying antiemetic treatment guidelines to take into account symptom expectancies. Finally, ethically acceptable interventions that are designed to reduce patients' nausea expectancies or increase their expectancies of nausea control should be developed and studied.

Eye movement, vection, and motion sickness with foveal and peripheral vision

BACKGROUND

Both motion sickness and the illusion of self-motion (i.e., vection) can be induced by moving visual scenes. The results of a previous study imply that motion sickness is primarily dependent on visual motion in foveal vision while vection is primarily dependent on motion in peripheral vision.

HYPOTHESIS

It was hypothesized that similar motion sickness would be produced when tracking a single moving dot and a full screen of moving dots, but that vection would be greater when tracking multiple moving dots.

METHOD

Sixteen subjects viewed moving images presented on a virtual reality head-mounted display. In one condition a single dot moved from left to right at 27 degrees x s(-1) over a distance of 18 degrees before returning instantly to its starting point. This motion was repeated continuously. In a second condition, five horizontal rows of dots, each 18 degrees apart, moved continuously across the screen at 27 degrees x s(-1); subjects were instructed to track each dot in the central row as it passed.

RESULTS

In both conditions, there were nystagmic eye movements with an approximate amplitude of 18 degrees at 27 degrees x s(-1). Vection differed significantly between the two conditions, with more vection in the condition with five rows of dots. Subjects experienced motion sickness symptoms with both the single moving dot and the five rows of dots, with no significant difference in sickness between the two conditions. Subject ratings of motion sickness and vection were not correlated with each other in either of the two conditions.

CONCLUSIONS

Motion sickness and vection can vary independently. Vection appears to be influenced by peripheral vision, as there was an increase in vection with full-field stimulation. Motion sickness induced by moving visual scenes may be influenced by foveal visual stimulation or by eye movements, as these were the same in both conditions.

Behavioral contagion in an experimental motion environment

BACKGROUND

It is generally understood that whole-body movement up and down can produce motion sickness. A standard reference, published in this journal in 1974, found that a frequency of 6 cycles per minute was most productive of motion sickness. The 1974 study used a vertical oscillator carrying two subjects at a time. The investigators were, of course, aware that the sight, sound, or smell of another person being ill might itself contribute to sickness. Accordingly, the two subjects were located in completely separate compartments, each soundproofed and with its own independent air-conditioning system. The sessions were scheduled to last 2 h. However, if a subject "pre-terminated" (became ill or requested removal), the oscillator was stopped while the subject debarked.

METHODS

The present study is a secondary analysis of data elements not reported in the original study, namely, the frequency of pairs in which 0, 1, or 2 subjects pre-terminated. If knowing that the other subject had pre-terminated had no effect on whether the remaining subject pre-terminated, then the pairs in which 0, 1, or 2 subjects pre-terminated should be distributed binomially.

RESULTS

Independent pre-termination of the two subjects in a pair was rejected (p < 0.001). The likelihood that a subject would pre-terminate increased strongly when the subject's partner pre-terminated. This effect was twice as large when the motions of the oscillator were severe as when they were less severe.

CONCLUSIONS

Pre-termination by one subject legitimized pre-termination by example, and thereby increased the risk that the remaining subject would also pre-terminate (behavioral contagion).

What to expect from immersive virtual environment exposure: influences of gender, body mass index, and past experience

For those interested in using head-coupled PC-based immersive virtual environment (VE) technology to train, entertain, or inform, it is essential to understand the effects this technology has on its users. This study investigated potential adverse effects, including the sickness associated with exposure and extreme responses (emesis, flashbacks). Participants were exposed to a VE for 15 to 60 min, with either complete or streamlined navigational control and simple or complex scenes, after which time measures of sickness were obtained. More than 80% of participants experienced nausea, oculomotor disturbances, and/or disorientation, with disorientation potentially lasting > 24 hr. Of the participants, 12.9% prematurely ended their exposure because of adverse effects; of these, 9.2% experienced an emetic response, whereas only 1.2% of all participants experienced emesis. The results indicate that designers may be able to reduce these rates by limiting exposure duration and reducing the degrees of freedom of the user's navigational control. Results from gender, body mass, and past experience comparisons indicated it may be possible to identify those who will experience adverse effects attributable to exposure and warn such individuals. Applications for this research include military, entertainment, and any other interactive systems for which designers seek to avoid adverse effects associated with exposure.

[Selection of vestibular system function in Chinese astronauts]

OBJECTIVE

To examine and evaluate the vestibular function of Chinese astronaut candidates in order to select the astronauts with good vestibular function.

METHOD

Fifty-nine male candidates, the fighter plane pilots, participated in the Caloric tests, and 38 pilots among all the candidates experienced the parallel swing and Coriolis acceleration stimuli in tests. The parameters, such as vestibule-autonomic nervous reflex symptoms, electrogastrography (EGG), electronystagmography (ENG), ECG, blood pressure, postural equilibrium ability were employed to evaluate the vestibular function.

RESULT

Caloric tests indicated that there were function symmetry on both sides of semicircular canals, as well as normality of visual-vestibular and vestibulo-ocular reflexes in all the candidates. The parallel swing and Coriolis acceleration stimulus demonstrated that there were differences of vestibular functions in 38 pilots. Incidence of I category (stability type) of vestibular function exceeded 52.6%, and II category (relatively stable type) approached 42.1% as well III category (relatively susceptible type) was reported to be 5.3%.

CONCLUSION

Vestibular function of astronaut candidates could be evaluated comprehensively and objectively in the present tests. The Chinese astronauts can be chosen from the candidates with stable type or relatively stable type up to standard vestibular function.

Motion sickness and postoperative vomiting in children

BACKGROUND

Motion sickness is considered an important risk factor for postoperative nausea and vomiting in children. The aim of this study was to verify the impact of motion sickness on the incidence of vomiting after routine surgery in children, and to compare the incidence of vomiting, after combined regional/general anaesthesia, using either halothane or sevoflurane.

METHODS

We prospectively studied 420 children (369 males and 51 females) who received general anaesthesia and inguinal field block for common paediatric surgery. The children were randomly allocated into one of two groups (halothane or sevoflurane). In the 200 children in the first group (H), general anaesthesia was induced and maintained with halothane, whereas in the 220 children in the second group (S), anaesthesia was induced and maintained with sevoflurane.

RESULTS

There were 79 children with a prior history of motion sickness (MS+) and 341 without such a history (MS-). In the MS+ population, the incidence of vomiting was similar in both H and S groups, being around 33%. However, repeated episodes of vomiting in MS+ children were more frequent when halothane was used. In the MS- group, the incidence of vomiting was significantly greater in the H group (19%) than in the S group (8%).

CONCLUSIONS

In the postoperative period, we found that MS+ children vomit more than MS- children, regardless of the inhalation anaesthetic used. However, MS- children displayed a higher incidence of vomiting when halothane was used rather than sevoflurane.

Performance Evaluation Tests for Environmental Research (PETER): critical tracking test

A critical tracking test was considered for inclusion in the Performance Evaluation Tests for Environmental Research (PETER) Battery which was designed for use in unusual environments. Baseline measures were obtained by testing 18 subjects for 14 consecutive days. Mean performances increased but standard deviations were constant over the 14 days. Test-retest reliabilities improved over the first 8 days after which differential stability was seen. The implications for the use of this test in exotic environments are discussed. The critical tracking test is recommended as a good candidate for environmental research when practiced to total stability.

Effects of retention intervals on the magnitude of optokinetic rotation-induced taste aversions

This study investigated the effects of different retention intervals on the magnitude of optokinetic rotation-induced conditioned taste aversions in humans. Two experiments were conducted. In Exp. 1, 20 subjects were divided into two groups, a CS-UCS group in which drinking soybean milk was paired with optokinetic rotation-induced gastric illness and a CS-Only group in which drinking soybean milk was not paired with optokinetic rotation. Analysis indicated that two days after pairing soybean milk drinking with optokinetic rotation, the subjects in the CS-UCS group had significantly reduced palatability ratings of soybean milk and lower consumption of soybean milk than those in the CS-Only group. In Exp. 2, 40 subjects were divided into four CS-UCS groups with 1-day, 3-day, 5 day, and 10-day retention intervals between the session of pairing soybean milk with optokinetic rotation and the session of retasting soybean milk. Analysis yielded no significant differences among four groups on palatability of soybean milk and consumption of soybean milk in the retasting session. It is concluded that optokinetic rotation is an effective unconditioned stimulus for conditioned taste aversions formation and that the aversion has a retention period of at least 10 days.

The effect of betahistine on vestibular habituation: comparison of rotatory and sway habituation training

This study was designed to investigate the effect of histaminergic agonists and antagonists on the acquisition of vestibular habituation. The experimental animals, pigeons, were subjected to unilateral rotatory and sway habituation training sessions. The habituation of postural reflexes and post-rotatory head nystagmus was assessed. Vestibular habituation in the control group was achieved by adopting the kinetic reflex posture after approximately 9 training sessions, and after 10 and 14 training sessions, respectively for 50% reduction of the total number of beats (TNB) and the duration of post-rotatory head nystagmus. In the sway adaptation test control pigeons needed nearly 15 training sessions while pigeons receiving betahistine adapted after approximately 8 sessions. Administration of histamine and, most notably, betahistine accelerated the process, while both H1 and H2 antagonists (clemastine, cimetidine) tended to retard it, indicating a less significant contribution of H2 receptors. The cholinergic agent physostigmine strongly retarded habituation while the anticholinergic agent scopolamine markedly accelerated it. In addition the adrenomimetic agent ephedrine also accelerated habituation while the adrenolytic agent droperidol retarded reduction of nystagmus beats. The results indicate that histaminergic receptors play a significant role in the vestibular habituation mechanism but are intricately involved with other types of receptors. Betahistine is clearly the agent of choice for attenuating vestibular effects.

Comparison of granisetron, droperidol, and metoclopramide for prevention of postoperative vomiting in children with a history of motion sickness undergoing tonsillectomy

BACKGROUND/PURPOSE

A history of motion sickness is one of the patient-related factors associated with postoperative vomiting (POV). This study was undertaken to compare the efficacy of granisetron, droperidol, and metoclopramide for the prevention of POV after tonsillectomy in children with a history of motion sickness.

METHODS

In a prospective, randomized, double-blinded trial, 90 pediatric patients, aged 4 to 10 years, received granisetron, 40 microg/kg; droperidol, 50 microg/kg; or metoclopramide, 0.25 mg/kg (n = 30 of each) intravenously after an inhalation induction of anesthesia. Emetic episodes and safety assessments were performed during the first 24 hours after anesthesia.

RESULTS

Twenty-two of 30 patients (73%) who had received granisetron were emesis free during the first 24 hours after surgery as compared with 7 of 30 (23%) who had received droperidol (P <.05) or 6 of 30 (20%) who had received metoclopramide (P <.05). No clinically serious adverse events were observed in any of the groups.

CONCLUSION

Prophylactic therapy with granisetron is superior to droperidol or metoclopramide for the prevention of POV after tonsillectomy in children with a history of motion sickness.

Panic disorder among Vietnamese refugees attending a psychiatric clinic: prevalence and subtypes

This study surveys Vietnamese refugees attending two psychiatric clinics to determine both the prevalence of panic disorder (PD) as well as panic attack subtypes in those suffering PD. A culturally valid adaptation of the SCID-panic module (the Vietnamese Panic Disorder Survey or VPDS) was administered to 100 Vietnamese refugees attending two psychiatric clinics. Utilizing culturally sensitive panic probes, the VPDS provides information regarding both the presence of PD and panic attack subtypes during the month prior to interview. Of 100 patients surveyed, 50 (50%) currently suffered PD. Among the 50 patients suffering PD, the most common panic attack subtypes during the previous month were the following: "orthostatic dizziness" (74% of the 50 panic disorder patients [PDPs]), headache (50% of PDPs), wind-induced/temperature-shift-induced (24% of PDPs), effort-induced (18% of PDPs), gastro-intestinal (16% of PDPs), micturition-induced (8% of PDPs), out-of-the-blue palpitations (24% of PDPs), and out-of-the-blue shortness of breath (16% of PDPs). Five mechanisms are adduced to account for this high PD prevalence as well as the specific profile of subtypes: 1) a trauma-caused panic attack diathesis; 2) trauma-event cues; 3) ethnic differences in physiology; 4) catastrophic cognitions generated by cultural syndromes; and 5) a modification of Clark's spiral of panic.

Outpatient tympanomastoidectomy: factors affecting hospital admission

BACKGROUND

Outpatient tympanomastoidectomy is common in many medical centers. However, failure of same-day discharge is often the result of postoperative nausea and vomiting (PONV). Many times this leads to hospital admission after tympanomastoidectomy, and it is often difficult to predict before surgery whether PONV will be an issue that impedes same-day discharge.

OBJECTIVE

To determine the clinical factors correlated with the incidence of PONV requiring hospital admission after chronic ear surgery by hypothesizing that the complexity of a particular case, as measured using a 10-point scale, is predictive of surgical time or failure of same-day hospital discharge.

STUDY DESIGN

Retrospective medical chart review of 103 patients having mastoidectomy with tympanoplasty for chronic otitis media over a 2-year period.

METHODS

We recorded patient age, clinical data, surgical times, types of agents used for induction and maintenance of anesthesia, use of prophylactic antiemetic drugs, types and doses of analgesic agents, and PONV. Univariate and multivariate logistic regression analyses were performed to determine which variables were associated with PONV that required hospital admission.

RESULTS

One third of patients studied were safely discharged from the hospital the day of surgery, and 92% were discharged within 23 hours. The most common cause for observation admission to the hospital was PONV. The only variable in multivariate analysis that significantly correlated with PONV mandating hospital admission after tympanomastoid surgery was a history of motion sickness or PONV (odds ratio, 5.21; P =.02). Although severity of disease did not correlate with length of hospital stay, it directly correlated with length of surgery.

CONCLUSIONS

A history of PONV or motion sickness is predictive of PONV and length of hospital stay. Routine planning for a 23-hour overnight observation stay seems warranted for all patients undergoing tympanomastoidectomy, despite severity of disease.

Vestibular reactions to spaceflight: human factors issues

Vestibular function, along with other sensory systems influencing spatial orientation, can have a profound influence on the ability of astronauts to function effectively. Beyond the well-known problems of space motion sickness, vestibular effects can influence astronaut well-being and performance during all phases of a space mission. This paper discusses some of the major vestibular reactions affecting human factors encountered in all space missions, and covers them chronologically in the following sequence: launch, early on-orbit, late on-orbit, EVA, artificial gravity, re-entry, and post-landing.

Head roll compensation in a visually coupled HMD: considerations for helicopter operations

BACKGROUND

The helmet-mounted display (HMD) research program at the Flight Research Laboratory of the National Research Council of Canada examined the effects of HMD camera platform dynamics on pilot workload. Many currently fielded visually coupled HMD systems do not reproduce head movements in the roll axis which can lead to the presentation of visual information that is not consistent with vestibular and proprioceptive information.

HYPOTHESIS

Our hypothesis was that this sensory conflict can induce motion sickness and increase pilot workload.

METHODS

To examine this premise, three pilots flew a series of standardized maneuvers with or without roll compensation in the camera platform of a visually coupled HMD system.

RESULTS

Increases in motion sickness symptoms and pilot workload were noted during complex, high-workload maneuvers when no roll compensation was present in the camera platform. During the most demanding maneuvers, the lack of roll compensation in the camera platform made it difficult for the evaluation pilot to control the helicopter.

CONCLUSIONS

Roll compensation in visually coupled HMD systems reduces pilot workload and' motion sickness during critical flight periods where pilot workload may already be considerable.

Evaluation of three risk scores to predict postoperative nausea and vomiting

BACKGROUND

So far there are three different scores to predict postoperative vomiting (PV: Apfel et al., 1998) or postoperative nausea and vomiting (PONV: Koivuranta et al., 1997; Palazzo and Evans, 1993). All three scores used logistic regression analysis to identify and create weights for the risk factors for PV or PONV. In short, these were sex, age, history of previous PONV, motion sickness, duration of anaesthesia, and use of postoperative opioids. However, an external evaluation and a comparison of these scores has not been performed so far.

METHODS

Patients undergoing a variety of surgical procedures under general anaesthesia were studied prospectively. Preoperatively, they completed a questionnaire concerning potential risk factors for the occurrence of PV or PONV implemented in the three risk scores. Balanced anaesthesia (induction agent, nondepolarising neuromuscular blocker, opioid, and inhalation agent in nitrous oxide/oxygen) was performed. No intravenous anaesthesia or any antiemetic prophylaxis was applied. Postoperatively, the patients were observed in the recovery room for the occurrence of PV and PONV and were visited twice on the ward within the 24-h observation period. Both the patients and the nursing staff were asked whether PV or PONV was present. The severity of PONV was categorised using a standardised scoring algorithm. A total of 1,444 patients was finally included into the analysis. Using information of the predicted risk for the individual patients and the actual occurrence of PV or PONV, Receiver Operator Characteristics (ROC-curves) were drawn. The area under each ROC-curve was calculated as a means of the predictive properties of each score and was compared for statistical differences.

RESULTS

For prediction of PONV (any severity) the AUC-values (AUC=area under the curve) and the corresponding 95%-confidence intervals were: Apfel: 0.70 (0.67-0.72); Koivuranta: 0.71 (0.69-0.73); Palazzo: 0.68 (0.65-0.70). For prediction of PV: Apfel: 0.73 (0.71-0.75); Koivuranta: 0.73 (0.70-0.75); Palazzo: 0.68 (0.65-0.70). Thus, all three scores appeared to have a moderate accuracy as measured by the AUC. The score of Koivuranta predicts PONV (P=0.007) and also PV (P=0.002) significantly better than Palazzo's score. Furthermore, for predicting of PV the score of Apfel was also superior to Palazzo's score (P=0.005). All three scores predict PV with the same accuracy as PONV.

CONCLUSION

The occurrence of PV and PONV in patients undergoing surgery under balanced anaesthesia can be predicted with moderate but acceptable accuracy using one of the available risk scores, regardless of local surgical or anaesthesiological circumstances. For clinical practice, we recommend the score published by Koivuranta, since its calculation is very simple.

Motion sickness

The number of recently published papers on motion sickness may convey the impression that motion sickness is far from being understood. The current review focusses on a concept which tends to unify the different manifestations and theories of motion sickness. The paper highlights the relations between ergonomic principles to minimise motion sickness and the concept predictions. The clinical management of sufferers from motion sickness in terms of selection, pharmacological measures and desensitisation courses is treated as well.

Postural instability and motion sickness in a fixed-based flight simulator

We evaluated the prediction that postural instability would precede the subjective symptoms of motion sickness in a fixed-base flight simulator. Participants sat in a cockpit in a video projection dome and were exposed to optical flow that oscillated in the roll axis with exposure durations typical of flight simulation. The frequencies of oscillation were those that characterize spontaneous postural sway during stance. Head motion was measured prior to and during exposure to imposed optical flow. Of 14 participants, 6 were classified as motion sick, either during or after exposure to the optical oscillation. Prior to the onset of subjective symptoms, head motion among participants who later became sick was significantly greater than among participants who did not become motion sick. We argue that the results support the postural instability theory of motion sickness. Actual or potential applications include the prevention or mitigation of motion sickness in virtual environments.