Oxygen nitrous oxide and

Midazolam (Versed), a short-acting benzodiazepine CNS depressant, is used as a preanesthetic drug to relieve anxiety for induction of anesthesia for conscious sedation before minor procedures, such as endoscopic procedures and to supplement nitrous oxide and oxygen for short surgical procedures. When the drug is used for induction anesthesia, the patient gradually loses consciousness during a period of 1 to 2 minutes. 

Halothane (Fluothane) is a volatile liquid given by inhalation for induction and maintenance of anesthesia Induction and recovery from anesthesia are rapid, and the depth of anesthesia can be rapidly altered. Halothane does not irritate the respiratory tract, and an increase in tracheobronchial secretions usually does not occur. Halothane produces moderate muscle relaxation, but skeletal muscle relaxants may be used in certain types of surgeries. This anesthetic may be given with a mixture of nitrous oxide and oxygen. 

Splitter block for mixing nitrous oxide and oxygen. 

For inhalational induction of anaesthesia in children, 6% sevoflurane in 50% nitrous oxide and oxygen is probably optimal. However, some anaesthetists consider it to be inferior to halothane for the management of the irritable or constricted airway and for anaesthesia for bronchoscopy. Sevoflurane is preferred for dental procedures as there is a lower risk of cardiac arrhythmias than with halothane, especially in children. In children with congenital heart disease, whereas the cardiac index is reduced by halothane it is preserved with sevoflurane. In adults, 8% sevoflurane is well tolerated and, provides rapid induction of anaesthesia without adversely affecting haemodynamic stability. 

Entonox is a 50% mixture of nitrous oxide and oxygen which remains gaseous under pressure unless the ambient temperature falls below -5.5°C. In these circumstances the contents may separate into liquid nitrous oxide and gaseous oxygen. In such a situation there is a risk that at the start high percentage concentrations of oxygen could be delivered followed by almost pure nitrous oxide. 

Depth of anesthesia is determined by the concentration of anesthetic agent that reaches the brain. Brain concentration, in turn, depends on the solubility and transport of the anesthetic agent in the bloodstream and on its partial pressure in inhaled air. Anesthetic potency is usually expressed as a minimum alveolar concentration (MAC), defined as the percent concentration of anesthetic in inhaled air that results in anesthesia in 50% of patients. As shown in Table 9.6, nitrous oxide, N2O, is the least potent of the common anesthetics. Fewer than 50% of patients are immobilized by breathing an 80 20 mix of nitrous oxide and oxygen. Methoxyflurane is the most potent agent a partial pressure of only 1.2 mm Hg is sufficient to anesthetize 50% of patients, and a partial pressure of 1.4 mm Hg will anesthetize 95%. 

American obstetricians used nitrous oxide as a common pain management tool for women in labor through the early 1970s. Today, the anesthetic has been largely replaced in the United States, but a 50/50 mix of nitrous oxide and oxygen is still the anesthetic of choice for women in labor in the UK—over 60% use the gas for pain relief. 

And somewhat ironically, nitrous oxide appears to have some use as an treatment for withdrawal symptoms. Several South African studies have demonstrated the usefulness of nitrous oxide in treating withdrawal symptoms and reducing cravings during alcohol, marijuana, and nicotine detoxification. And in early 2002, a small study published in Clinical Psychiatry found that the gas may also be helpful in helping smokers kick the habit. Researchers found that 92% of patients who inhaled a 50%/50% mixture of nitrous oxide and oxygen... 

It is important to note that there have been no harmful physiological effects observed in infants bom to mothers who are administered nitrous oxide and oxygen during labor itself, as the gas is quickly metabolized. However, a few long-term studies have shown a possible link between heavy nitrous oxide use during labor and... 

The oxidation of carbon monoxide by nitrous oxide and oxygen over a silver catalyst at 20°C was analysed by both the Hougen -Watson procedure and the transient response method. The rival models derived from both procedures were clearly distinguished by the mode of the transient response curves of C02 or N caused by the concentration jump of CO, 02 or N20. 

H0jberg O., Revsbech N. P., and Tiedje J. M. (1994) Denitrification in soil aggregates analyzed with microsensors for nitrous oxide and oxygen. Soil Sci. Soc. Am. J. 58, 1691-1698. 

During this long evacuation the boy was in considerable distress and we administered Entonox (a mixture of nitrous oxide and oxygen, 50% each) sparingly as we only had one small cylinder. He repeatedly remarked how much better he felt after each intake of Entonox (approximately every 20 minutes) and after 7 hours or so we eventually got him safely into the ambulance and on his way to hospital. 

Inhalation via a demand valve of nitrous oxide and oxygen, as in obstetrics, may be used temporarily in other situations e.g. urinary lithiasis, trigeminal neuralgia, during postoperative chest physiotherapy, for changing painful dressings and in emergency ambulances. 

Most commonly with nitrous oxide and oxygen, or oxygen and air, plus a volatile agent, e.g., isoflurane or sevoflurane. Additional doses of a neuromuscular blocker or opioid are given as required. 

Entonox, a 50 50 mixture of nitrous oxide and oxygen, is breathed by the patient using a demand valve. It is particularly useful in the prehospital environment and for brief procedures, such as splinting limbs. 

Nitrous oxide and oxygen (50% of each Entonox) may be administered for each contraction from a machine the patient works herself or supervised by a midwife (about 10 good breaths are needed for maximal analgesia). 

The results of the study of the decomposition of nitrous oxide at 250° on a divided nickel oxide confirm therefore that the surface structure of a catalyst may be modihed in the course of the catalytic reaction at a moderate temperature. They have shown, moreover, that different gases (nitrous oxide and oxygen) which are both oxidizing agents, may induce, at the same temperature, different modifications of the surface defect structure of the solid and therefore, change its catalytic activity in different ways. 

Inhalation of high 1,1,1-trichloroethane concentrations can produce anesthesia in humans (Dornette and Jones 1960). Dornette and Jones (1960) tested the use of 1,1,1-trichloroethane as a general anesthetic in 50 hospital patients. The effective concentration for induction of anesthesia varied from 10,000 to 26,000 ppm. Onset of anesthesia was extremely rapid, taking place within 2 minutes of the start of exposure. Maintenance of light anesthesia for <2 hours required 6,000-22,500 ppm. Recovery from anesthesia occurred within 5 minutes of the end of exposure. In this study, 1,1,1-trichloroethane was co-administered with nitrous oxide and oxygen, and the effect of... 

Finally, nitrous oxide is not used in the United States but is a common analgesic in many developed countries. A 50-50 blend of nitrous oxide and oxygen is the most commonly used mixture. Women can self-administer the medication or receive it continuously under medical supervision. Women report significant pain relief. The side effects include nausea, vomiting, and poor recall of labor. ... 

Alfentanil, an opiate analgesic (8 to 50 mcg/kg IV), is indicated as an adjunct to general anesthetic in the maintenance of general anesthesia with barbiturate, nitrous oxide, and oxygen. In addition, it is used as a primary anesthetic for induction of anesthesia when endotracheal intubation and mechanical ventilation are required. 

Sufentanil, an opioid analgesic (8 mcg/kg IV administered with nitrous oxide and oxygen), is indicated in patients undergoing major surgical procedures, such as cardiovascular surgery or neurosurgical procedures in the sitting position, in order to provide favorable myocardial and... 

Eight out of 17 digitalised patients (anaesthetised with thiamylal and then maintained with nitrous oxide and oxygen) developed serious ventricular arrhythmias following the intravenous injection of suxamethonium (suc-cinylcholine)40 to 100 mg. Four out of the 8 patients reverted to their previous rhythm when they were given tubocurarine 15 to 30 mg, with one patient returning to a regular nodal rhythm from ventricular tachycardia. ... 

P-15 Filling of Industrial and Medical Nonflammable Compressed Gas Cylinders. Covers prefill inspection procedures and describes the steps necessary to ensure cylinders of air, argon, carbon dioxide, helium, nitrogen, nitrous oxide, and oxygen are filled in a manner that is safe (19 pages). 

Medical Gases—gases or mixtures of gases used in medical applications. Examples are air, carbon dioxide, helium, nitrogen, nitrous oxide, and oxygen. 

The United States Pharmacopeia/National Formulary contains a section or monograph on each of the following gases air, carbon dioxide, cyclopropane, helium, nitrogen, nitrous oxide, and oxygen. Definite standards and methods of testing are prescribed in each USP/NF monograph to assure a product of appropriate quality and purity. 

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