Nitrous oxide for chronic pain

BACKGROUND: Chronic pain can often occur after surgery, substantially impairing patients' health and quality of life. It is caused by complex mechanisms that are not yet well understood. The predictable nature of most surgical procedures has allowed for the conduct of randomized controlled trials of pharmacological interventions aimed at preventing chronic postsurgical pain. OBJECTIVES: The primary objective was to evaluate the efficacy of systemic drugs for the prevention of chronic pain after surgery by examining the proportion of patients reporting pain three months or more after surgery...

OBJECTIVE: The objective of this review was to provide a general descriptive account of the physical properties, end-organ effects, therapeutic applications, and delivery techniques of nitrous oxide (N2O) as used in the arena of procedural sedation. DATA SOURCE: A computerized bibliographic search regarding the applications of nitrous for provision of sedation and analgesia during procedures with an emphasis on the pediatric population was performed. RESULTS: The end-organ effects of N2O have been well described in the operating room setting...

Nitrous oxide is an antagonist at the N-methyl-D-aspartate receptor and may prevent the development of chronic postsurgical pain. We conducted a follow-up study in the Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA) trial patients to evaluate the preventive analgesic efficacy of nitrous oxide after major surgery. The ENIGMA trial was a randomized controlled trial of nitrous oxide-based or nitrous oxide-free general anesthesia in patients presenting for noncardiac surgery lasting more than 2 hours...

UNLABELLED: Laparoscopy is an effective method of implantation for peritoneal dialysis (PD) catheters. Use of the laparoscopic technique is increasing because of its potential advantages over other techniques. In most patients, selection for PD is based on negative criteria, and because of the need for general anesthesia, the laparoscopic technique can be life-threatening in these patients. On the other hand, local anesthesia is insufficient for laparoscopic catheter implantation. To avoid the need for general anesthesia and to achieve patient safety and satisfaction, we designed a type of conscious sedation (dissociative conscious sedation) and compared the efficacy of subcutaneous (SC) and intravenous (IV) ketamine added to narcotics in patients scheduled for laparoscopic implantation of a PD catheter...

BACKGROUND: Mechanical debridement of fibrin and/or necrosis promotes healing of arterial and venous leg ulcers but is limited by pain associated with the procedure. OBJECTIVE: The main objective of this study was to compare the respective analgesic effect of nitrous oxide oxygen mixture (NOOM) inhalation and lidocaïne-prilocaïne cream (LPC) application during the mechanical repeated debridement of chronic arterial and venous leg ulcers. METHODS: In this randomized, multicentre, open-label study, pain was evaluated before and after each care and debridement session using a Visual Analog Scale (VAS) and a Verbal Rating Scale (VRS), in the context of usual debridement and wound care process...

UNLABELLED: Using the rat chronic constriction injury (CCI) pain model, we evaluated whether nitrous oxide (N2O), a gas shown to have potent anti-hyperalgesic properties, may alleviate neuropathic pain. Mechanical nociceptive threshold was estimated using the paw pressure vocalization test. Thermal allodynia was challenged by measuring the struggle latency by immersion of the hind paw in a 10 degrees C water bath. A single 50% N2O exposure for 1 hour, 15 minutes not only induced potent anti-nociception during N2O exposure but also provoked a delayed and sustained reduction (37% to 46%) of pain hypersensitivity of the injured hind paw and abolished pain hypersensitivity of the contralateral uninjured hind paw for at least 1 month...

Prolonged exposure to nitrous oxide (N2O) results in development of acute tolerance to its antinociceptive effect. Cross-tolerance to N2O-induced antinociception is also observed in morphine-tolerant animals. Despite increasing evidence of tolerance development to N2O-induced antinociception, the details of the mechanisms that underlie this tolerance remain unknown. The present study was conducted to investigate the involvement of brain protein kinase C (PKC) isoform in these two types of tolerance to N2O-induced antinociception in mice...

Electrical tooth stimulation was used to investigate whether humans develop tolerance to nitrous oxide (N(2)O) analgesia within a single administration as well as over repeated administrations. In a double-blind cross-over experiment, 77 subjects received a 40-min administration of 38% N(2)O at one session and placebo gas at the other. The sessions were separated by 1 week and the order of gas administration was counterbalanced. Acute analgesic tolerance developed for pain threshold but not for detection threshold...

The aim of this study was to evaluate whether distraction induced by video glasses had an effect on the perceived intensity of pain and unpleasantness during dental scaling compared with the effect of nitrous oxide (N(2)O) analgesia. The pain stimulus was dental scaling (removal of dental calculus) with an ultrasonic scaler. As a standardised, non-dental painful stimulus, Von Frey filaments were used. A total of 26 patients with superficial chronic periodontitis were enrolled in this randomised, controlled clinical study...

BACKGROUND: Nausea, vomiting and pain are common complications after strabismus surgery in children. Diclofenac, a non-steroid anti-inflammatory drug, is widely used to treat acute and chronic pain but there are few reports of its use given rectally in children undergoing strabismus surgery. This open randomised study was designed to investigate the analgesic and anti-emetic properties of rectally administered diclofenac compared with opioid (morphine) given i.v. in connection with strabismus surgery in children...

BACKGROUND: The authors recently established that the analgesic actions of the inhalation anesthetic nitrous oxide were mediated by noradrenergic bulbospinal neurons and spinal alpha2B adrenoceptors. They now determined whether noradrenergic brainstem nuclei and descending spinal pathways are responsible for the antinociceptive actions of the inhalation anesthetic isoflurane, and which alpha adrenoceptors mediate this effect. METHODS: After selective lesioning of noradrenergic nuclei by intracerebroventricular application of the mitochondrial toxin saporin coupled to the antibody directed against dopamine beta hydroxylase (DbetaH-saporin), the antinociceptive action of isoflurane was determined...

Nitrous oxide may be used to alleviate dental anxiety and to diminish or eliminate dental pain. The benefit of nitrous oxide sedation is a cooperative and satisfied patient. By reducing the patient's perception of pain it allows them to relax and cooperate during dental procedures. However, the dental surgery personnel, chronically exposed to N2O, are at serious risk. The chronic effects of occupational exposure to nitrous oxide have long been the subject of debate. Safety standards have been established in the United States and Europe since many years...

Burn pain can cause psychologic and functional difficulties, and is difficult to predict from wound depth. The initial painful stimulation of nerve endings by the burn with continued painful stimuli result in peripheral and central mechanisms causing amplification of painful stimuli, and the development of chronic pain syndromes that can be difficult to treat. In order to assess the effect of analgesic interventions it is essential to measure the patient's pain in a simple and reproducible manner. A number of tools exist for this measurement, ranging from longer and more detailed techniques such as the McGill pain questionnaire most suited to relatively stable pain, to visual analogue scores and picture-based scores for children...

OBJECTIVE: Although percutaneous liver biopsy (PLB) can be a painful procedure, common practice has not included intravenous sedation or analgesia. Patient-administered nitrous oxide/oxygen (N2O/O2) inhalation has demonstrated analgesic efficacy in various procedures associated with mild to moderate pain. The aim of this study was to investigate the safety and efficacy of analgesia with N2O/O2 inhalation for PLB. METHODS: One hundred consecutive patients undergoing a first PLB (for chronic hepatitis C: 56, for alcoholic liver disease: 23, for miscellaneous reasons: 21)...

The effect of L-arginine in long-term parenteral administration was studied on a model of neuropathic pain syndrome and adjuvant arthritis. L-arginine produced a preventive and therapeutic effect in the neuropathic pain syndrome. It weakened the development of adjuvant arthritis for the period of its administration. The factor underlying the effect of L-arginine is its double action as a precursor of nitrous oxide and kiotorphin, an endogenous antinociceptive dipeptide.

The history of office-based anesthesia dates back to the discovery of nitrous oxide and ether in the 1840s. In recent years, advances in intravenous anesthetic techniques and the rising costs of hospital-based services have combined to promote the practice of ambulatory anesthesia. Dental patients who may benefit from office-based anesthesia include patients undergoing stressful procedures, fearful patients, medically or behaviorally challenged patients, young children, and patients with a history of gagging or local anesthesia problems...

To evaluate the efficacy of continuous administration of 50% nitrous oxide in oxygen for reducing pain during flexible fiberoptic bronchoscopy 32 children aged 3-60 months were randomly assigned to an experimental or a control group. Indications for endoscopy included persistent atelectasis (6), wheezing (10) cystic fibrosis (2) pneumonia (11) persistent cough (3). All patients received Midazolam (0.3 mg/kg) atropine (20 mcg/kg) intra rectaly 20 minutes before the procedure. The flexible fiberoptic bronchoscope (Olympus BF3C4) was inserted transnasally through a face mask...

The pulmonary complications remain the prime cause of morbidity and mortality in sickle cell disease. The pathogenetic mechanisms consists both of an alteration of the rheological properties of the blood, the existence of a hypercoagulability state and above all specific interactions between the abnormal sickle cells and the vascular endothelium and a dysregulation of the vascular reactivity in which nitrous oxide intervenes. The acute chest syndrome (ACS) is characterised by chest pain with dyspnoea and recent radiological abnormalities and it is an acute lung complication whose problem is one of aetiology...

To study the possible benefits of N2O pneumoperitoneum, 40 patients scheduled for laparoscopic cholecystectomy for symptomatic cholelithiasis were randomized into either CO2-induced (n = 20) or N2O-induced (n = 20) pneumoperitoneum groups. The intensity of postoperative pain was assessed by the patients themselves using an visual analogue pain score scale. CO2 insufflation caused respiratory acidosis. The total amount of anesthetic enflurane needed was lower in the N2O than in the CO2 group (p < 0.041). The N2O group experienced less pain 1 hour (p < 0...

Nitrous oxide continues to be a valuable agent for the control of pain and anxiety. However, chronic occupational exposure in dental offices not using scavenging systems may be associated with possible deleterious neurological and reproductive effects. This report outlines recommendations for controlling nitrous oxide exposure that were made by an expert panel convened by the ADA.