Medical preparedness, incidents, and group dynamics during the analog MARS2013 mission.

Participants on spaceflights and international scientific analog Mars missions can encounter medical incidents (accidents, illnesses) and psychological issues (e.g., stress, group interaction, sleep disturbance, emotions). The aim of this study was to examine these parameters in a field crew living in a desert environment similar to Mars (Group 1) and in Mission Support Center (MSC) personnel on "Earth" (Group 2) during a 4-week mission. Of the 107 medical interventions in the field, 73 mainly minor incidents together with four near accidents and 29 medical checkup interventions were recorded. Of the 32 medical interventions, medical treatments for 23 incidents of minor severity were necessary in Group 2. Injuries (Group 1: 1.4/100 h, Group 2: 0.1/100 h) were significantly increased in the field, and illnesses (Group 1: 0.3/100 h, Group 2: 3.0/100 h) in the MSC personnel. Causes of accidents and illnesses are described. Psychological results show that emotions and stress remained stable in both groups. Sympathy, social competence, teamwork, and leadership showed high scores. These scores were lower on "Earth" but significantly increased in the last weeks. The Sahara's nighttime coldness was reflected in an increased wake-up frequency, and a longer sleeping time peaked in the third week, probably as a result of overfatigue. MARS2013 was a successful mission with highly motivated participants and minor medical incidents. For future analog missions and possibly long-distance open-space missions, some recommendations in terms of medical and psychological preparedness are made to reduce risks for field crew members and MSC personnel.

Mode of anesthesia, mortality and outcome in geriatric patients.

BACKGROUND: In older non-cardiac surgery patients, the influence of the mode of anesthesia on late-term outcome (rehabilitation, mobility, independence) is a controversial issue in the medical literature. In light of an aging society, this review assessed the association between regional (RA), local (LA) and general anesthesia (GA) and mortality and morbidity. METHODS: A literature search within the PubMed and Cochrane databases yielded 47 clinical trials and 35 reviews/meta-analyses published between 1965 and 2013. Potential outcome-influencing factors such as mortality, risk factors, early complications (e.g. postoperative confusion, aspiration, vomiting), adverse events (e.g. deep vein thrombosis, pulmonary embolism), discharge, rehabilitation and mobilization were evaluated in relation to the mode of anesthesia (RA, LA or GA). RESULTS: The current literature contains 82 references covering 74,476 non-cardiac surgery patients. Analysis shows that the particular mode of anesthesia influences mortality and morbidity. RA is associated with reduced early mortality and morbidity, e.g. fewer incidents of deep vein thrombosis and less acute postoperative confusion, as well as a tendency toward fewer myocardial infarctions and fatal pulmonary embolisms. GA has the advantages of a lower incidence of hypotension and reduced surgery time. CONCLUSION: Strictly speaking, true anesthesia-related complications appear to be rare and many adverse outcomes may be multifactorial. Postoperative complications are largely related to the perioperative procedure and not to the anesthesia itself. GA and RA are both useful for older non-cardiac patients, but for some procedures, e.g. hip fracture surgery, RA seems to be the technique of choice. The mode of anesthesia may only play a secondary role in mobility, rehabilitation and discharge destination. In general, due to the many different possible outcomes--which are often very difficult or impossible to compare--no other specific recommendations can be made with regard to the type of anesthesia to be preferred for older non-cardiac patients.

The Tyrolean Geriatric Fracture Center: an orthogeriatric co-management model.

BACKGROUND: The aging population is growing rapidly and this change results in an increase in the number of fragility fracture patients. Several reports describe their poor outcome. Integrated models of care have been published in order to improve quality of patient care. We established an orthogeriatric model of care at the Department of Trauma Surgery in Innsbruck in cooperation with the Department of Geriatric Medicine (Hochzirl) and the Department for Anesthesiology. This report describes our concept as well as initial experience. PATIENTS AND METHODS: We included all geriatric patients according to the definition of the German Geriatric Society. In all patients, basic demographic data, Charlson Comorbidity Index, and type of fracture were recorded. Main principles of the newly implemented system are the integration of a geriatrician in our team of trauma surgeons and anesthesiologists, prioritization of patients, development of our own clinical treatment guidelines, regular interdisciplinary and interprofessional meetings, a special outpatient clinic for these patients, and the better cooperation with the nearby Department of Geriatric Medicine. RESULTS: A total of 529 patients met our inclusion criteria during 2010; 77.4% were female and the mean age was 84.1 years. The overall medical complication rate was 20.4%. Of the patients, 36.1% had hip fractures and 70.5% could be operated mainly using spinal anesthesia within 24 h and their mean length of stay was significantly shorter than operations performed 5 years previously. At 3 months, 86.7% of the patients had returned home and, thus, had reached their prefracture residency. CONCLUSION: A coordinated, multidisciplinary model for the treatment of fragility fractures has the potential to improve the quality of patient care. Several international studies report superior outcome and our own findings are promising as well. We could show that our major goals, e.g., reduction of complications, shortening the length of stay, and restoration of the prefracture residency, can be improved by implementing such a model.

Neuroaxial versus general anaesthesia in geriatric patients for hip fracture surgery: does it matter?

The influence of the mode of anaesthesia on outcome of geriatric patients with hip fractures is a controversial issue in the medical literature. In the light of an ageing society, a conclusive answer to this question is of growing importance. The purpose of this review was to assess the effect of neuroaxial and general anaesthesia on mortality and morbidity in geriatric patients sustaining a hip fracture. Following a current literature search within the Pubmed and Cochrane database (1967-2010), 34 randomised controlled trials, 14 observational studies and eight reviews/meta-analysis publications were included. Potentially outcome-influencing factors such as mortality, deep vein thrombosis, pulmonary embolism, postoperative confusion and other anaesthesia-related outcomes were evaluated. After analysing the current literature with 56 references, covering 18,715 patients with hip fracture, it can be concluded that spinal anaesthesia is associated with significantly reduced early mortality, fewer incidents of deep vein thrombosis, less acute postoperative confusion, a tendency to fewer myocardial infarctions, fewer cases of pneumonia, fatal pulmonary embolism and postoperative hypoxia. General anaesthesia has the advantages of having a lower incidence of hypotension and a tendency towards fewer cerebrovascular accidents compared to neuroaxial anaesthesia. Otherwise, general anaesthesia and respiratory diseases were significant predictors of morbidity in hip fracture patients. These data suggest that regional anaesthesia is the preferred technique, but the limited evidence available does not permit a definitive conclusion to be drawn for mortality or other outcomes. For hip fracture surgery, the choice of anaesthesia (general or neuroaxial) is made by the anaesthesiologist and is based on the patient's preference, comorbidities, potential general postoperative complications and the clinical experience of the anaesthesiologist. The overall therapeutic approach in hip fracture care should be determined jointly by the orthopaedic surgeon, the geriatrician and the anaesthesiologist (multidisciplinary approach).

Outcome in geriatric fracture patients and how it can be improved.

Geriatric fractures are an increasing medical problem worldwide. This article wants to give an overview on the literature concerning the outcome to be expected in geriatric fracture patients and what can be done to improve it. In literature, excess mortality rates vary from 12% to 35% in the first year after a hip fracture, and also, other geriatric fractures seem to reduce the patient's remaining lifetime. Geriatric fractures and, in particular, hip fractures constitute a major source of disability and diminished quality of life in the elderly. Age, gender, comorbid conditions, prefracture functional abilities, and fracture type have an impact on the outcome regarding ambulation, activities of daily living, and quality of life. Comprehensive orthogeriatric comanagement might improve the outcome of geriatric fracture patients. For the future, well designed, large prospective randomized controlled trials with clear outcome variables are needed to finally prove the effectiveness of existing concepts.

Ortho-geriatric service--a literature review comparing different models.

In the fast-growing geriatric population, we are confronted with both osteoporosis, which makes fixation of fractures more and more challenging, and several comorbidities, which are most likely to cause postoperative complications. Several models of shared care for these patients are described, and the goal of our systematic literature research was to point out the differences of the individual models. A systematic electronic database search was performed, identifying articles that evaluate in a multidisciplinary approach the elderly hip fracture patients, including at least a geriatrician and an orthopedic surgeon focused on in-hospital treatment. The different investigations were categorized into four groups defined by the type of intervention. The main outcome parameters were pooled across the studies and weighted by sample size. Out of 656 potentially relevant citations, 21 could be extracted and categorized into four groups. Regarding the main outcome parameters, the group with integrated care could show the lowest in-hospital mortality rate (1.14%), the lowest length of stay (7.39 days), and the lowest mean time to surgery (1.43 days). No clear statement could be found for the medical complication rates and the activities of daily living due to their inhomogeneity when comparing the models. The review of these investigations cannot tell us the best model, but there is a trend toward more recent models using an integrated approach. Integrated care summarizes all the positive features reported in the various investigations like integration of a Geriatrician in the trauma unit, having a multidisciplinary team, prioritizing the geriatric fracture patients, and developing guidelines for the patients' treatment. Each hospital implementing a special model for geriatric hip fracture patients should collect detailed data about the patients, process of care, and outcomes to be able to participate in audit processes and avoid peerlessness.

Urinary retention after spinal anaesthesia with hyperbaric prilocaine 2% in an ambulatory setting.

BACKGROUND: Hyperbaric prilocaine 2% is a medium long-acting spinal anaesthetic. There are few data on time to recovery and rate of urinary retention after spinal administration of hyperbaric prilocaine 2%. This prospective study was carried out to evaluate the time to spontaneous micturition, quantify the rate of necessary bladder catheterizations, and identify the risk factors for urinary retention after intrathecal prilocaine administration. METHODS: ASA I/II patients (16-80 yr) undergoing ambulatory lower limb surgery were enrolled and received spinal anaesthesia using hyperbaric prilocaine 2% (60 mg). Ringer's lactate was administered for peroperative volume replacement. Bladder ultrasound was performed hourly until spontaneous micturition or catheterization, when bladder filling reached 600 ml, and they were unable to urinate spontaneously. RESULTS: Eighty-six patients completed the study (49 males and 37 females). Mean (sd) fluid administration was 1200 (499) ml until either micturition or catheterization; 37.8% of the women and 12.2% of the men required catheterization (P=0.009). Mean (sd) time between spinal anaesthesia and catheterization was 190 (88) min, and 260 (61) min to micturition (P<0.0001). Age <40 or >60 yr and female gender were predisposing factors for urinary retention. CONCLUSIONS: After spinal anaesthesia with hyperbaric prilocaine 2% (60 mg) for ambulatory lower limb surgery, 23% of patients required postoperative urinary catheterization. Postoperative bladder ultrasound and early catheterization are essential to avoid bladder distension and facilitate discharge in patients after intrathecal prilocaine 2% administration in ambulatory surgery.

Remifentanil and nitrous oxide reduce changes in cerebral blood flow velocity in the middle cerebral artery caused by pain.

BACKGROUND: Cerebral blood flow is affected by painful stimuli, and analgesic agents may alter the response of cerebral blood flow to pain. We set out to quantify the effects of remifentanil and nitrous oxide on blood flow changes caused by experimental pain. METHODS: We simulated surgical pain in 10 conscious volunteers using increasing mechanical pressure to the tibia. We measured changes in cerebral blood flow velocity in the middle cerebral artery (CBFV(MCA)) caused by the pain, using transcranial Doppler sonography. We gave increasing doses of remifentanil (0.025, 0.05 and 0.1 micro g kg(-1) min(-1)) or nitrous oxide [20%, 35% and 50% end-tidal concentration (FE'(N(2)O))] and compared these effects on blood flow changes. RESULTS: Nitrous oxide increased CBFV(MCA) only when given at 50% FE'(N(2)O). Remifentanil did not affect CBFV(MCA). Pain increased CBFV(MCA). Both agents attenuated this pain-induced change in CBFV(MCA) with the exception of nitrous oxide at 20% FE'(N(2)O). CONCLUSIONS: Inhalation of nitrous oxide or adminstration of remifentanil attenuated pain-induced changes in CBFV(MCA).

The influence of nitrous oxide and remifentanil on cerebral hemodynamics in conscious human volunteers.

Remifentanil is increasingly used in the context of anesthesia, e.g., in patients presenting for MRI examinations, not only as an analgesic but also to replace nitrous oxide. Therefore, a comparative analysis of the effects of commonly used doses of remifentanil and of nitrous oxide on cerebral hemodynamics is warranted. The present study used contrast-enhanced magnetic resonance (MR) perfusion measurement to compare the effects of nitrous oxide (N(2)O/O(2) = 50%; n = 9) and remifentanil (0.1 microg/kg/min; n = 10) on regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), and regional mean transit time (rMTT) in spontaneously breathing human volunteers. Remifentanil increased rCBF above all in basal ganglia, whereas in supratentorial gray matter the increase in rCBF was equal or even more pronounced when using nitrous oxide. In contrast, nitrous oxide produced a greater increase in rCBV in gray-matter regions than did remifentanil. In summary, nitrous oxide increased rCBV in all gray-matter regions more than did remifentanil. However, the increase in rCBF, especially in basal ganglia, was typically less pronounced than during infusion of remifentanil.

Cardiological monitoring of sailors via offshore Internet connection.

BACKGROUND: Sailing is becoming increasingly popular as a form of holiday recreation. The purpose of the present study was to profile the heart rate characteristics of non-professional crew members on a Mediterranean sailboat trip. Additionally, the practicability of transferring electronic data via the Internet while sailing offshore was also studied. METHODS: Seven healthy male non-professional crew members responsible for steering and navigating the boat during the observation period were studied using continuous electrocardiographic recording (Holter). Manually measured blood pressure, side effects and sailing data were taped half-hourly. RESULTS: While sailing we observed that the heart rate increased typically into the 120-170 beats/min range, mean arterial pressure remained stable between 80-90 mmHg. Heart rate changes and the incidence of supraventricular arrhythmias correlated with activity on board, boat speed and wind velocity. No subject showed ventricular arrhythmias during sailing. The minimal blood pressure changes correlated only with activity on board. CONCLUSIONS: All these results indicate that sailboating on vacation, even in a non-professional status, does not promote disease-relevant changes in heart rhythm on trips in mild to moderate seas. Additionally, we were able to demonstrate that the online transfer of electronic data via the Internet from a sailboat offshore is possible, easy and inexpensive.

Influence of equianaesthetic concentrations of nitrous oxide and isoflurane on regional cerebral blood flow, regional cerebral blood volume, and regional mean transit time in human volunteers.

Nitrous oxide and isoflurane have cerebral vasodilatory effects. The use of isoflurane in neuroanaesthesia is widely accepted, whereas the use of nitrous oxide in neuroanaesthesia is still the subject of debate. In the present study, contrast-enhanced magnetic resonance (MR) perfusion measurement was used to compare the effects of 0.4 MAC nitrous oxide (n=9) and 0.4 MAC isoflurane (n=9) on regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and regional mean transit time (rMTT) in spontaneously breathing human volunteers. Nitrous oxide increased rCBF and rCBV in supratentorial regions more than did isoflurane. Isoflurane, by contrast, increased rCBF and rCBV in basal ganglia more than did nitrous oxide. An increased rMTT was caused by a relatively greater increase in rCBV than in rCBF supratentorially by isoflurane and infratentorially by nitrous oxide. In conclusion, nitrous oxide increases rCBF and rCBV predominantly in supratentorial grey matter, whereas isoflurane increases rCBF and rCBV predominantly in infratentorial grey matter.

Oxygen application by a nasal probe prevents hypoxia but not rebreathing of carbon dioxide in patients undergoing eye surgery under local anaesthesia.

BACKGROUND/AIM: Hypoxia and carbon dioxide rebreathing are potential problems during eye surgery in spontaneously breathing patients. The aim of the present study was to determine effectiveness of nasal application of oxygen to prevent hypoxia and carbon dioxide accumulation in spontaneously breathing patients undergoing cataract surgery. METHODS: Oxygenation and carbon dioxide rebreathing were examined in 40 elderly patients using two different methods of oxygen supply-nasal v ambient air-with a constant flow of 2 l/min. Partial pressure of carbon dioxide under ophthalmic drapes, transcutaneous pressure of carbon dioxide, and the respiratory rate were measured during 25 minutes while oxygen was supplied via a nasal cannula or into the ambient air under the drapes. RESULTS: In both groups carbon dioxide accumulation under the drapes, carbon dioxide rebreathing, tachypnoea, and an increase in peripheral oxygen saturation occurred. No significant differences were found between the two methods. CONCLUSION: Nasal application of oxygen prevented hypoxia but did not prevent carbon dioxide accumulation in patients undergoing eye surgery under retrobulbar anaesthesia. Additionally, as a side effect when using nasal probes, irritation of the nose was described in half of the patients investigated.

Effect of fluvoxamine on sufentanil antinociception and tolerance under chronic intravenous infusion in rats.

Fluvoxamine, a selective serotonin reuptake inhibitor (SSRI), significantly potentiates analgesia when administered in animals together with opioids. The aim of the present study was to investigate the effects of fluvoxamine on sufentanil antinociception and tolerance. Following animal care committee approval, the effects of continuous infusions of fluvoxamine and sufentanil were studied in behavioural tests (hot-plate test, tail-flick test, catalepsy test) in Sprague-Dawley rats with a jugular vein catheter. Saline was administered as a control. The time-effect curves for continuous intravenous sufentanil indicate dose-related antinociception and rapid development of tolerance in the hot-plate and tail-flick tests. Co-administration of fluvoxamine with continuous sufentanil enhances antinociception and attenuates development of tolerance, most clearly seen in the tail-flick test. Fluvoxamine alone and saline were not effective. No animal showed catalepsy. As a side effect we observed a marked loss of body weight. The IC50 values of sufentanil binding with and without fluvoxamine addition are 0.56+/-0.17 nM and 0.3+/-0.15 nM, respectively, indicating no direct effect on the occupancy of sufentanil on the mu-receptor by this serotonin reuptake inhibitor. In conclusion, we were able to show that the combination of an opioid with an SSRI at low doses improves analgesia and decreases development of tolerance in nociceptive tests in rats. The clinical implications of these promising results in an animal model, however, await further investigation.

Cotreatment with racemic fenfluramine inhibits the development of tolerance to morphine analgesia in rats.

As a follow-up study to an earlier report that racemic fenfluramine can acutely potentiate the analgesic effects of morphine in humans, we investigated the effects of fenfluramine on the development of tolerance to morphine analgesia in rats. Antinociceptive effect, as measured by the tail-flick latency, was studied over 8 days in rats that received continuous i.v. infusion of 1) 22 mg/kg/day of morphine, 2) 20 mg/kg/day of fenfluramine, 3) both drugs concomitantly or 4) saline. Infusion with morphine alone resulted in a peak analgesia of 100% maximal possible effect, which declined with time; full tolerance was reached by day 4. Fenfluramine treatment alone had no effect. Fenfluramine coinfusion attenuated the development of tolerance to morphine; >70% maximal possible effect was still present on day 4. The effect of fenfluramine coinfusion occurred in the absence of a significant increase in plasma or brain morphine concentration, or a decrease in the accumulation of morphine's putative antagonistic metabolite, morphine-3-glucuronide. In another set of infusion experiments, rats were challenged with a single i.p. dose of morphine to characterize the morphine dose-response curves at 10 hr following 4-day i.v. infusion of 1) 22 mg/kg/day of morphine, 2) 20 mg/kg/day fenfluramine, 3) morphine plus fenfluramine or 4) saline. An acute i. p. morphine challenge dose response experiment was also conducted in naïve control rats and in rats receiving a concomitant i.p. injection of fenfluramine (2.4 mg/kg). Coinjection of fenfluramine acutely potentiated the antinociceptive potency of morphine. However, potentiation alone does not fully account for the apparent attenuation of tolerance during morphine i.v. infusion. ED50 of morphine was elevated to 7.0 mg/kg in the morphine-infused rats compared to 2.4 mg/kg in saline-infused rats. Coinfusion of fenfluramine increased ED50 to only 3.7 mg/kg. These results demonstrate that fenfluramine significantly attenuates tolerance development to morphine by modulating the pharmacological process responsible for tolerance development to morphine.

Patient outcomes with positive pressure versus spontaneous ventilation in non-paralysed adults with the laryngeal mask.

PURPOSE: To compare patient outcomes for positive pressure ventilation (PPV) and spontaneous ventilation (SV) in non-paralysed patients with the LMA using either isoflurane or sevoflurane anaesthesia. METHODS: One hundred and sixty four adult patients were studied. Anaesthesia was with fentanyl/propofol and N2O 66% in O2 with 0.75 MAC isoflurane or sevoflurane and either PPV or SV. Positive pressure ventilation was with tidal volumes of 6-8 ml.kg-1. Peak airway pressures were < 15 cm H2O. Patients were evaluated for airway problems, cardiorespiratory effects, and anaesthesia emergence times. RESULTS: There were no failed episodes of PPV or SV. Gastric insufflation was not detected by epigastric auscultation. Airway problems and cardiovascular effects were similar among groups. During maintenance: SpO2 was greater in the PPV group than in the SV group (98.4 vs 97%, P < 0.001); also, (PETCO2) (34 vs 43 mmHg) and the respiratory rate (RR) (15 vs 19 min-1) were higher and the minute ventilation (MV) (5.7 vs 7.2 L) were lower in the SV groups (P < 0.0001). Shorter times to LMA removal and orientation were observed in the sevoflurane groups (P < 0.0001). CONCLUSIONS: Patient outcome is similar for SV and PPV in non-paralysed adult patients with the LMA. Isoflurane and sevoflurane at 0.75 MAC provide suitable conditions for maintenance and emergence, but emergence is more rapid with sevoflurane.

Transcutaneous CO2/O2 and CO2/air suction in patients undergoing cataract surgery with retrobulbar anaesthesia.

We investigated transcutaneous partial CO2 and O2 pressures and respiratory rate in unpremedicated elderly patients of ASA physical status 1 to 3 who underwent cataract surgery under retrobulbar anaesthesia. In group A no air suction was used. In group B suction was applied under the sterile drapes to avoid rebreathing of CO2. In group A transcutaneous partial CO2 pressure and respiratory rate significantly increased compared with baseline, whereas in group B they remained constant. In both groups transcutaneous partial O2 pressure and oxygen saturation as measured by pulse oximetry significantly rose after insufflating oxygen 31.min-1. Heart rate and mean arterial blood pressure remained constant. Our results demonstrate that the application of suction near the patient's head prevents CO2 rebreathing and subsequent hypercapnia associated with an elevated respiratory rate. The use of suction makes it unnecessary to raise oxygen administration. Suction combined with monitoring of partial CO2 pressure using transcutaneous sensors should be used in all ophthalmological operations under retrobulbar anaesthesia.