COVID-19 et protoxyde d'azote pendant l'accouchement / COVID-19 and nitrous oxide during childbirth

PRÉSENTATION SOMMAIRE DE LA DEMANDE: Il a été demandé à l'INESSS de rechercher dans la littérature les données relatives à l'utilisation du protoxyde d'azote pendant l'accouchement en contexte de pandémie à la COVID-19 chez les femmes atteintes ou non du coronavirus afin d'en faire une utilisation optimale en contexte de pandémie et de crise. Le protoxyde d'azote (aussi appelé gaz hilarant ou oxyde nitreux) est un gaz incolore qui est utilisé, entre autres, en maintien de l'anesthésie générale ou comme analgésique (à dose subanesthésique) en obstétrique pendant l'accouchement. Lorsqu'il est utilisé comme analgésique, il doit être mélangé à de l'oxygène (50 %-50 %) et administré par inhalation par l'entremise d'un masque muni d'une valve à demande. Puisque ce gaz tend à dilater les cavités de l'organisme renfermant des gaz, le protoxyde d'azote serait contre-indiqué en présence d'air dans la plèvre, le péricarde ou le péritoine, de même que lors d'affection des voies aériennes chronique obstructive ou d'emphysème. MÉTHODOLOGIE: Questions d'évaluation: Quelles sont l'innocuité et les modalités d'utilisation du protoxyde d'azote pendant l'accouchement en contexte de pandémie à COVID-19? Critères de sélection: Population: Femmes atteintes ou non de la COVID-19. Intervention: Utilisation du protoxyde d'azote pendant l'accouchement Comparateur : Placebo ou autre analgésique Résultat d'intérêt : Innocuité, modalités d'utilisation. Types de documents retenus: Tout document contenant des informations pertinentes, que ce soit de la littérature scientifique ou de la littérature grise. Méthodes de recension: Date de recherch : 23 et 27 mars 2020. Une recherche rapide a été effectuée en utilisant les bases de données PubMed, MEDLINE, Embase, EBM Reviews et le moteur de recherche Google avec les mots-clés suivants: Coronavirus, pneumonia virus, 2019 ncov, COVID-19, nitrous Oxide, laughing gas, nitrogen protoxide, delivery, obstetric, childbirth, parturition, sage*-femme*, midwife*, midwives. Une recherche manuelle de la littérature a également été effectuée en consultant les sites Web des agences règlementaires, d'agences d'évaluation des technologies de la santé ainsi que ceux d'organismes gouvernementaux, d'associations ou ordres professionnels en lien avec le thème des travaux. Consultation menée: Aucune consultation d'experts n'a été menée dans le cadre de ces travaux. CONSTATS DE L'INESSS: Basé sur la documentation scientifique disponible au moment de sa rédaction, malgré l'incertitude existante dans cette documentation et dans la démarche utilisée de recension, il ressort que: Les recommandations liées à l'utilisation du protoxyde d'azote pendant l'accouchement chez les femmes confirmées ou suspectées COVID-19 sont divergentes selon les sociétés savantes ou organismes: Certains recommandent d'utiliser le protoxyde d'azote pendant l'accouchement en utilisant un filtre microbiologique pour prévenir la contamination du système d'inhalation du gaz; Certains recommandent d'utiliser le protoxyde d'azote pendant l'accouchement sans précision sur les précautions particulières; Certains recommandent d'évaluer les risques et bénéfices de l'utilisation du protoxyde d'azote pendant l'accouchement avant son utilisation vu les incertitudes entourant le nettoyage, les filtres à utiliser ainsi que le potentiel d'aérosolisation du produit; Certains ne mentionnent aucune opposition sur l'utilisation du protoxyde d'azote pendant l'accouchement puisqu'il n'existe aucune évidence que l'administration de ce médicament est une procédure pouvant générer des aérosols. Les incertitudes soulevées quant à la possibilité pour ce médicament de générer des aérosols rendent potentiellement nécessaire le port d'un équipement de protection approprié pour le personnel médical si utilisé par une personne avec statut COVID-19 positif ou suspecté. Or, ces équipements sont des ressources dont il serait judicieux de réserver l'usage pour des situations de nécessité absolue. De plus, le risque théorique de contamination par le virus du système d'administration du protoxyde d'azote est une considération importante.

Nitrous Oxide versus Medical Air Using in General Anaesthesia During Laparoscopic Cholecystectomy: A Comparative Study.

This study was designed to observe the haemodynamic changes, recovery status and cost effectiveness during anaesthesia in laparoscopic cholecystectomy with medical air in comparison to anaesthesia with nitrous oxide associated with maintain of adequate analgesia and was conducted in the department of Analgesia and Intensive Care Medicine, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from January 2017 to June 2017. Nitrous oxide is popularly using as an analgesic in current balanced general anesthesia in addition carrier agent for anesthetic. Intraoperative pain intensity depends on many variables including, type of surgery, surgical stimulation and surgical incision. It is difficult to measure intraoperative pain properly under general anesthesia therefore anesthetist depends on the surrogate marker of inadequate analgesia like raised heart rate, blood pressure, sweating and lacrimation. However, unfortunately, these parameters may changes in same direction with light plane of anesthesia, hypercarbia and ongoing procedural status of the patient.

Assessment of hypoxia, sedation level, and adverse events occurring during inhalation sedation using preadjusted mix of 30% nitrous oxide + 70%oxygen.

PURPOSE: To assess the efficacy of nitrous oxide (N2O)-oxygen (O2) inhalation sedation by rapid induction technique using preadjusted mix of 30% N2O and 70% O2 in children. MATERIALS AND METHODS: Sixty children with a treatment plan which included pulp therapy were recruited for the study. Children categorized 3 and 4 of Frankl behavior rating scale and American Society of Anesthesiologists health status I and II were included for the study. Children were distributed into study group (Group-I) and control group (Group-II) by fishbowl randomization. Children in Group-I were induced inhalation sedation using a preadjusted mix of 30% N2O and 70% O2 through rapid induction technique, and children in Group-II were exposed to inhalation sedation by conventional slow induction technique. Parameters such as least oxygen saturation, sedation levels by Richmond Agitation-Sedation Scale, time taken to achieve ideal sedation, maximum N2O concentrations used, and adverse events were recorded and evaluated for each procedure. Data were analyzed using independent sample t-test and Chi-square tests. RESULTS: Analysis of data showed statistically significant difference between both groups in time taken to achieve ideal sedation (P < 0.001). No significant difference was seen in incidence of hypoxia (P < 0.512), maximum N2O concentrations used (P < 0.118), and occurrence of any adverse events. CONCLUSION: None of the children from both groups exhibited hypoxia. Sense of detachment was seen in one child each from both groups. Rapid induction by preadjusted mix resulted in ideal sedation in 57% children of the Group-I; rest had achieved these levels at 40% N2O. There was a significant difference in the time taken to achieve ideal sedation by rapid induction which was almost half the time taken with slow induction.

Short Report. Audit of Conscious Sedation Provision in a Salaried Dental Service.

Clinical audit is a tool that may be used to improve the quality of care and outcomes for patients in a health care setting as well as a mechanism for clinicians to reflect on their performance. The audit described in this short report involved the collection and analysis of data related to the administration of 1,756 conscious sedations, categorised as standard techniques, by clinicians employed by an NHS Trust-based dental service during the year 2014. Data collected included gender, age and medical status of subject, the type of care delivered, the dose of drug administered and the quality of the achieved sedation and any sedation-related complications. This was the first time that a service-wide clinical audit had been undertaken with the objective of determining the safety and effectiveness of this aspect of care provision. Evaluation of the analysed data supported the perceived view that such care was being delivered satisfactorily. This on-going audit will collect data during year 2016 on the abandonment of clinical sessions, in which successful sedation had been achieved, due to the failure to obtain adequate local anaesthesia.

The outlook of physician histories: J. Marion Sims and 'The Discovery of Anaesthesia'.

The fact that doctors have a long tradition of writing medical history to interpret and direct their profession is well established. But readers (particularly modern physician readers) can also understand physician-authored histories as offering commentary and analysis of the world beyond medicine. In this essay, we offer a reading (perhaps a modern one) of J. Marion Sims's 1877 article, 'The Discovery of Anaesthesia' which exemplifies the stance of looking both inward and outward from the medical field. We begin by discussing Sims, including the complicated legacy he left as a physician. Next, we review late 19th-century history with a focus on Reconstruction. Finally, we show how the modern reader can use Sims's article both to trace the first use of ether and nitrous oxide for surgical anaesthesia and to provide a window into the 19th-century medical profession and the post-Civil War period. Through this study, we hope to show how to read both medicine and the world around it in physician histories.

Surgical and anesthetic considerations in histrelin capsule implantation for the treatment of precocious puberty.

BACKGROUND: Precocious puberty treatment traditionally meant anxiety-provoking monthly depot injections until the advent of the annually implanted histrelin capsule. This study is the first to evaluate the surgical and anesthetic aspects of histrelin implantation for precocious puberty. METHODS: All cases from one surgeon at a tertiary pediatric hospital were reviewed for patient age, anesthetic type, technical difficulties, and complications. RESULTS: From 12/2007 to 3/2013, 114 cases (49% implantations, 25% removals/re-implantations, 25% removals) were performed. Local anesthesia was employed in 100% of non-general anesthesia cases (n=109, 96%), augmented by inhaled N2O in 49%. Five patients (4%) underwent general anesthesia: three neurologically-impaired and two coordinated with scheduled MRIs. Procedural difficulties (n=18, 16%) included implant fracture during removal (n=16/58 removals, 28%). Fracture never occurred during implantation. Three children (3%) suffered complications. One infection was treated with antibiotics, and two implants were removed for systemic allergic reaction. Six children (5%) had unscheduled post-operative checks for pain (n=3, 3%), allergy to elastic dressing (n=2, 2%), or rash (n=1, 1%). Mean charges for general anesthesia were $10,188±1292 versus $528±147 for N2O or local alone (p<0.0001). CONCLUSION: While histrelin implantation is straightforward, removal presents technical challenges. Local anesthesia, with possible N2O supplementation, is well-tolerated and introduces substantial resource and cost savings.

Assessment of reinforcement enhancing effects of toluene vapor and nitrous oxide in intracranial self-stimulation.

RATIONALE: Despite widespread abuse, there are few validated methods to study the rewarding effects of inhalants. One model that may have utility for this purpose is intracranial self-stimulation (ICSS). OBJECTIVES: This study aims to compare and contrast the ICSS reward-facilitating effects of abused inhalants to other classes of abused drugs. Compounds were examined using two different ICSS procedures in mice to determine the generality of each drug's effects on ICSS and the sensitivity of the procedures. METHODS: Male C57BL/6J mice with electrodes implanted in the medial forebrain bundle were trained under a three-component rate-frequency as well as a progressive ratio (PR) ICSS procedure. The effects of nitrous oxide, toluene vapor, cocaine, and diazepam on ICSS were then examined. RESULTS: Concentrations of 1,360-2,900 parts per million (ppm) inhaled toluene vapor significantly facilitated ICSS in the rate-frequency procedure and 1,360 ppm increased PR breakpoint. A concentration of 40 % nitrous oxide facilitated ICSS in the rate-frequency procedure but reduced PR breakpoint. Doses of 3-18 mg/kg cocaine facilitated ICSS in the rate-frequency procedure, and 10 and 18 mg/kg increased PR breakpoint. Doses of 1 and 3 mg/kg diazepam facilitated ICSS in the rate-frequency procedure, and 3 mg/kg increased PR breakpoint. CONCLUSIONS: The reinforcement-facilitating effect of toluene in ICSS is at least as great as diazepam. By contrast, nitrous oxide weakly enhances ICSS in only the rate-frequency procedure. The data suggest that the rate-frequency procedure may be more sensitive than the PR schedule to the reward-facilitating effects of abused inhalants.

[Renal denervation for resistant hypertension without general anesthesia: advantage of a MEOPA morphine protocol. Preliminary experience]. / Dénervation rénale pour HTA réfractaire sans anesthésie générale : intérêt d'un protocole MEOPA Morphine. Expérience préliminaire.

UNLABELLED: Renal denervation using the technique of radiofrequency is used only recently for the treatment of resistant hypertension. Normally, it is done under general anesthesia because the ablation point technique is painful. We suggest an alternative to general anesthesia comprising an association of morphin 0.1mg/kg IV to MEOPA (gas combining oxygen and azot protoxyd) delivered through an oxygen mask. Our series includes 12 consecutive patients treated between October 2011 and June 2013, the first five patients (group 1) have received only an hydroxizin and morphin sedation. Every five have felt the ablation painful, in two cases bearable pain (EVA<5), in three cases intense (EVA>5) pain leading to increasing doses of morphin, (total dose of 0.25mg/kg in two cases, 0.17mg in one case). For the seven following patients, a protocol including hydroxyzin, morphin and MEOPA given through a mask has been set up. Only one patient has felt a mild pain (EVA 5) leading to an increasing dose of morphin (total dose 0.17mg/kg). None of the six other patients has felt any pain during the procedure. The average dose of morphin is 0.17mg/kg in group 1, 0.11mg/kg in group 2. This is a preliminary study; if confirmed, it will allow a lot of hospitals without on-site possibilities of general anesthesia, to realize such procedures. CONCLUSION: regarding pain, the procedure of renal ablation was well tolerated for six among seven patients receiving the association MEOPA and IV morphin. In contrast, in the five patients treated only with IV morphin, we observed a less good tolerance to pain and the need to increase the doses of IV morphin.

Must we press on until a young mother dies? Remifentanil patient controlled analgesia in labour may not be suited as a "poor man's epidural".

BACKGROUND: The epidural route is still considered the gold standard for labour analgesia, although it is not without serious consequences when incorrect placement goes unrecognized, e.g. in case of intravascular, intrathecal and subdural placements. Until now there has not been a viable alternative to epidural analgesia especially in view of the neonatal outcome and the need for respiratory support when long-acting opioids are used via the parenteral route. Pethidine and meptazinol are far from ideal having been described as providing rather sedation than analgesia, affecting the cardiotocograph (CTG), causing fetal acidosis and having active metabolites with prolonged half-lives especially in the neonate. Despite these obvious shortcomings, intramuscular and intravenously administered pethidine and comparable substances are still frequently used in delivery units. Since the end of the 90 ths remifentanil administered in a patient-controlled mode (PCA) had been reported as a useful alternative for labour analgesia in those women who either don't want, can't have or don't need epidural analgesia. DISCUSSION: In view of the need for conversion to central neuraxial blocks and the analgesic effect remifentanil has been demonstrated to be superior to pethidine. Despite being less effective in terms of the resulting pain scores, clinical studies suggest that the satisfaction with analgesia may be comparable to that obtained with epidural analgesia. Owing to this fact, remifentanil has gained a place in modern labour analgesia in many institutions. However, the fact that remifentanil may cause harm should not be forgotten when the use of this potent mu-agonist is considered for the use in labouring women. In the setting of one-to-one midwifery care, appropriate monitoring and providing that enough experience exists with this potent opioid and the treatment of potential complications, remifentanil PCA is a useful option in addition to epidural analgesia and other central neuraxial blocks. Already described serious consequences should remind us not refer to remifentanil PCA as a "poor man's epidural" and to safely administer remifentanil with an appropriate indication. SUMMARY: Therefore, the authors conclude that economic considerations and potential cost-savings in conjunction with remifentanil PCA may not be appropriate main endpoints when studying this valuable method for labour analgesia.

Impact of remifentanil introduction on practice patterns in general anesthesia.

PURPOSE: The introduction of new medicine can change clinical practice patterns and may affect patient outcomes. In the present study, we investigated whether introduction of remifentanil in Japan affected the practice patterns of anesthesia. METHODS: Using the Japanese Diagnosis Procedure Combination database, we extracted records of 423,491 patients who underwent surgery with general anesthesia in 243 hospitals before (2006) and after (2007) the introduction of remifentanil, and identified anesthetic agents used for each patient. A hierarchical mixed-effects logistic regression analysis was performed to analyze the factors that affected selection of remifentanil. Further, we compared postoperative length of stay (LOS), in-hospital mortality, and total costs between 2006 and 2007. RESULTS: In 2007, remifentanil was used for up to 41.4% of all general anesthesia, accompanied by a reduction in nitrous oxide use and an increase in total intravenous anesthesia. Female gender, increasing age, and preoperative comorbidities including diabetes mellitus, hypertension, liver cirrhosis, and chronic renal failure were positively associated with the use of remifentanil, whereas accompanying cardiac disease and co-application of epidural anesthesia were negatively associated. In 2007, a similar in-hospital death rate, similar or decreased total costs, slightly reduced duration of anesthesia, and substantially reduced postoperative LOS were seen compared to those in 2006. CONCLUSIONS: Our data revealed rapid changes in practice patterns in anesthesia after the introduction of remifentanil in Japan. Remifentanil was used more often in patients with comorbidities and without epidural anesthesia, and its introduction did not affect increase in total medical costs.

[Fatalities due to nitrous oxide. Complications from mistakes in nitrous oxide supply]. / Lachgasbedingte Todesfälle. Komplikationen durch Verwechslungen in der Lachgaszufuhr.

Despite inspiratory oxygen fraction measurement being regulated by law in the European norm EN 740, fatal errors in nitrous oxide delivery still occur more frequently than expected, especially after construction or repair of gas connection tubes. Therefore, if nitrous oxide is to be used further in a hospital, all technical measures and system procedures should be employed to avoid future catastrophes. Among these are measurement of the inspiratory oxygen fraction (F(I)O(2)) and an automatic limitation of nitrous oxide. Also all anaesthetists involved should be informed about repair or construction of central gas supply tubes. Additionally, more awareness of this problem in daily routine is necessary. Furthermore, a system of detecting and analysing errors in anaesthesia has to be improved in each hospital as well as in the anaesthesia community as a whole. Measures for a better "error culture" could include data exchange between different critical incident reporting systems, analysis of closed claims, and integration of medical experts in examination of recent catastrophes.

The effects of fresh gas flow on the amount of sevoflurane vaporized during 1 minimum alveolar concentration anaesthesia for day surgery: a clinical study.

BACKGROUND: Even small costs per case can become economically significant in high volume day surgical units. While general anaesthesia with higher fresh gas flow rates has technical advantages, they result in higher costs. The aim of the present study was to evaluate drug consumption and direct costs related to variations in the fresh gas flow and use of nitrous oxide at a 1 minimum alveolar concentration (MAC) sevoflurane end-tidal anaesthesia for day surgery. METHODS: Thirty-two ASA I-II patients undergoing elective day surgery under general anaesthesia [14 (10-21) min] were studied. Induction was with propofol and fentanyl 100 microg. After laryngeal mask airway placement, patients were randomized to one of four different fresh gas flows: 1 or 2 l/min oxygen in air (50% oxygen), 3 l/min (33% oxygen), or 3 l/min oxygen in nitrous oxide (33% oxygen). Anaesthesia was maintained at 1 MAC. The vaporizer was weighed before and after each procedure. The primary study variable was the sevoflurane utilization per minute. RESULTS: Sevoflurane utilization increased with increasing fresh gas flow for oxygen in air (r2 = 0.89). The nitrous oxide in oxygen group had the lowest sevoflurane utilization, even compared with the lowest oxygen in air group (0.36 vs. 0.48 g/min). CONCLUSION: Sevoflurane utilization during 1 MAC anaesthesia increases linearly with fresh gas flow and is still higher than when nitrous oxide is used even with very low fresh gas flow rates. Direct inhaled anaesthesia-related costs are consequently 20% higher than when nitrous oxide is used, even for the lowest oxygen in air fresh gas flows.

Pharmaceutical prescribing for children. Part 5. Conscious sedation for dentistry in children.

This is the fifth paper in a series on the prescribing of medicines for children by dentists working in primary dental care. It deals with conscious sedation for children.

Assessment of heat production, heat loss, and core temperature during nitrous oxide exposure: a new paradigm for studying drug effects and opponent responses.

Studies using core temperature (T(c)) have contributed greatly to theoretical explanations of drug tolerance and its relationship to key features of addiction, including dependence, withdrawal, and relapse. Many theoretical accounts of tolerance propose that a given drug-induced psychobiological disturbance elicits opponent responses that contribute to tolerance development. This proposal and its theoretical extensions (e.g., conditioning as a mechanism of chronic tolerance) have been inferred from dependent variables, such as T(c), which represent the summation of multiple underlying determinants. Direct measurements of determinants could increase the understanding of opponent processes in tolerance, dependence, and withdrawal. The proximal determinants of T(c) are metabolic heat production (HP) and heat loss (HL). We developed a novel system for simultaneously quantifying HP (indirect calorimetry), HL (direct gradient layer calorimetry), and T(c) (telemetry) during steady-state administrations of nitrous oxide (N(2)O), an inhalant with abuse potential that has been previously used to study acute and chronic tolerance development to its hypothermia-inducing property. Rats were administered 60% N(2)O (n = 18) or placebo gas (n = 16) for 5 h after a 2-h placebo baseline exposure. On average, N(2)O rapidly but transiently lowered HP and increased HL, each by approximately 16% (P < 0.001). On average, rats reestablished and maintained thermal equilibrium (HP = HL) at a hypothermic T(c) (-1.6 degrees C). However, some rats entered positive heat balance (HP > HL) after becoming hypothermic such that acute tolerance developed, i.e., T(c) rose despite continued drug administration. This work is the first to directly quantify the thermal determinants of T(c) during administration of a drug of abuse and establishes a new paradigm for studying opponent processes involved in acute and chronic hypothermic tolerance development.

Nitrous oxide analgesia for minor pediatric surgical procedures: an effective alternative to conscious sedation?

BACKGROUND/PURPOSE: Minor surgical procedures in children, while usually not requiring general anesthesia, need effective control of pain, anxiety, and motion. Certain techniques of conscious sedation may result in loss of protective airway reflexes. Nitrous oxide, however, when inhaled at levels below 50% maintains protective reflexes and does not require fasting or postprocedure monitoring. This study prospectively examines the efficacy of nitrous oxide analgesia in children undergoing outpatient surgical procedures. METHODS: Over a 2-year period (2000 to 2002), 150 consecutive children were given nitrous oxide analgesia as an alternative to a general anesthetic, sedation, or local anesthetic alone. Nitrous oxide (<50%) was administered by our practice's sedation-certified nurse practitioner without an anesthesiologist present. The children used the Wong-Baker Faces Scale (0-5) to score pain at different intervals (preprocedure, at injection, during procedure, and postprocedure) and event memories were tabulated. RESULTS: Of 150 children, 5 were uncooperative and could not participate. One hundred forty-five children, ages 1 to 20 years (Mean, 9.83 +/- 4.92 years) successfully underwent procedures (58 cyst/nevus excisions, 49 abscess drainages, 38 other) using nitrous. Two patients were too young to score pain. Pre- and postprocedure pain scores were significantly higher in the abscess group (P <.0001); during the procedures, however, all groups reported pain scores less than 1, with parents citing 100% satisfaction with the technique. Of 128 children receiving local anesthesia, 107 (84%) had no recall of the injection. Complications were limited to 4 patients; 2 experienced nausea, and 2 vomited. All resolved without interrupting the procedure. CONCLUSIONS: Nitrous oxide analgesia is a cost-effective and efficacious alternative to conscious sedation or general anesthesia for minor pediatric surgical procedures. In the office or outpatient setting, the technique provides for almost pain/anxiety-free surgery, no postoperative monitoring, and a high degree of satisfaction for patients, parents, and staff.

[Do short-term duration drugs for anaesthesia give postoperative advantages compared to traditional drugs?]. / Har totalintravenøs anestesi fordeler i den postoperative fase fremfor blandingsanestesi?

BACKGROUND: We wanted to compare totally intravenous anaesthesia with propofol and remifentanil to mixed anaesthesia with isoflurane and fentanyl in terms of postoperative pain, nausea, length of stay and costs. MATERIAL AND METHODS: We present a prospective, non-randomised, anaesthetist-based double-blind study with a cost-utility analysis on consecutive patients undergoing laparoscopic gynaecologic day-care surgery. Premedication consisted of paracetamol and diclofenac. The mixed anaesthesia group received propofol, isoflurane, fentanyl, vecuronium, N2O and O2,the total intravenous group propofol, remifentanil, vecuronium, N2O and O2. Paracetamol and ketobemidon, metoklopramid and ondansetron were given to relieve pain and nausea, respectively. Patients were asked to report pain and nausea on a visual analogue scale after 4 and 24 hours. RESULTS: 26 mixed and 27 totally intravenous patients were comparable by age, body mass index and ASA (American Society of Anesthesiologists) scores. There was a protocol violation, as fewer totally intravenous patients received pre-medication (16/26 vs. 8/27 p < 0.001). Totally intravenous patients had significantly higher consumption of ketobemidon (mean 2.35 vs. 5.43 mg/24 h p < 0.004). Within the totally intravenous group, scores for pain at 24 hours were significantly higher as compared with 4-hour scores (p = 0.012). At 24 hours, scores for nausea were significantly higher for the totally intravenous group (1.87 vs. 3.21 p = 0.014). Length of stay did not differ significantly (mean 649 vs. 729 min p > 0.2). Costs of medication were significantly higher for the totally intravenous group (mean 211 vs 285 NOK p <0.001). INTERPRETATION: The use of totally intravenous anaesthesia led to more nausea and more expenses than mixed anaesthesia in laparoscopic gynaecologic day-care surgery. No recommendations for either method can be made because of the non-randomized design.

Ceasing routine use of nitrous oxide-a follow up.

BACKGROUND: The role of nitrous oxide in modern anaesthesia is questioned. The routine use of nitrous oxide was almost completely stopped in our department after November 1, 2000, and we now report some consequences. METHODS: Staff completed a questionnaire after 6 months, and we analysed the use of hypnotics and opioids after 12 months. The cost of drugs for the year after stopping nitrous oxide was compared with the cost 2 yr before. RESULTS: Less than half of the 55 staff members who answered the questionnaire used nitrous oxide in the 6 months after the stop, and they did so on only a few occasions. Half of the staff members thought the benefit of nitrous oxide was small. Most supported the change. The use of opioids was stable during the study period, and there was an annual increase of 12-14% in the use of hypnotics during the 3 yr. CONCLUSIONS: The staff questionnaire showed a strong acceptance of the new policy, and the use of other anaesthetic agents did not increase as expected. Has the value of nitrous oxide been overestimated?

Are general dentists' practice patterns and attitudes about treating Medicaid-enrolled preschool age children related to dental school training?

PURPOSE: The purpose of this study were to investigate the willingness of general practitioners to provide dental care for preschool-aged children, and to explore the relationship between dental school experiences and practitioners' attitudes about treating Medicaid-enrolled children 3 years of age and younger. METHODS: A survey was mailed to 3,559 randomly selected general dentists in Texas. Respondents were asked to answer questions about their willingness to provide specified dental procedures for children of different ages, their dental school experiences with pediatric dentistry and whether these experiences were hands-on, lecture or no training, and their attitudes concerning treating Medicaid-enrolled children 3 years of age or younger. Associations between attitudes about treating Medicaid-enrolled children and dental school experiences were determined. RESULTS: The response rate was 26%. Almost all respondents were willing to provide routine procedures such as an examination (95%) and prophylaxis (94%) for children 5 years or younger. However, as children became younger and procedures more difficult, the number of general dentists willing to provide treatment decreased. The level of dental school training was significantly associated with the attitudes of general dentists about providing dental care for Medicaid-enrolled preschool-aged children (P < or = 0.05). CONCLUSION: Identification of factors associated with general dentists' willingness to see young children may improve access by increasing the number who will provide care for preschool-aged children.

An assessment of a method of inflating cuffs with a nitrous oxide gas mixture to prevent an increase in intracuff pressure in five different tracheal tube designs apparatus.

We assessed the efficacy of inflating cuffs with a nitrous oxide gas mixture to minimise changes in intracuff pressure during anaesthesia. Patients were randomly assigned to one of five groups of 15 subjects each, and the trachea was intubated with the Profile Soft-Seal Cuff, Hi-Contour, Reinforced, Sheridan or Trachelon tracheal tubes. Cuffs were inflated with 40% nitrous oxide and cuff pressure was measured during anaesthesia with 67% nitrous oxide. Concentration of nitrous oxide in the cuff was measured at the end of anaesthesia. Cuff pressure increased slightly but significantly in the Reinforced and Trachelon groups. Nitrous oxide concentration in the Reinforced, Sheridan, or Trachelon groups was slightly but significantly higher than that in the Profile or Hi-Contour groups. Cuff pressure never exceeded 22 mmHg and there were no air leaks. Therefore, inflating cuffs with 40% N2O preserves stable cuff pressure in all five tracheal tubes, despite differences in cuff and pilot balloon design.

Closed loop control of anaesthesia: an assessment of the bispectral index as the target of control.

We investigated the performance of a closed-loop system for administration of general anaesthesia, using the bispectral index as a target for control. One hundred patients undergoing gynaecological or general surgery were studied. In 60 patients, anaesthesia was maintained by intravenous infusion of a propofol/alfentanil mixture. In 40, an isoflurane/nitrous oxide based technique was used. For each technique, patients were randomly allocated to receive either closed-loop or manually controlled administration of the relevant agents (propofol/alfentanil or isoflurane), with an intra-operative target bispectral index of 50 in all cases. Closed-loop and manually controlled administration of anaesthesia resulted in similar intra-operative conditions and initial recovery characteristics. During maintenance of anaesthesia, cardiovascular and electro-encephalographic variables did not differ between closed-loop and manual control groups and deviation of bispectral index from the target value was similar. Intra-operative concentrations of propofol, alfentanil and isoflurane were within normal clinical ranges. Episodes of light anaesthesia were more common in the closed-loop group for patients receiving propofol/alfentanil anaesthesia and in the manual group for patients receiving isoflurane/nitrous oxide anaesthesia. Convenience aside, the closed-loop system showed no clinical advantage over conventional, manually adjusted techniques of anaesthetic administration.