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At least 199 records · Page 11Linked to original sources
PubMed2004

Endotracheal tubes versus laryngeal mask airways in rabbit inhalation anesthesia: ease of use and waste gas emissions.

In this study, we compared two endotracheal tubes (cuffed [Murphy Eye type] and uncuffed [Cole type]) and a pediatric laryngeal mask airway (LMA) with respect to their ease of use in rabbits and their capacities to limit waste isoflurane emissions. Animals (New Zealand White, 3.3 to 5.0 kg, n = 8) were sedated with intramuscular ketamine (50 mg/kg) and xylazine (10 mg/kg). After 5 min, the larynx was numbed with cetocaine, an intubation device was positioned, and anesthesia was maintained with isoflurane (2%) in oxygen (1 liter/min). Real-time atmospheric isoflurane emissions were assessed at the rabbit's oral commissure and in the operator's breathing zone (45 cm from the rabbit's nose) by using a portable infrared spectrophotometer. The LMA was placed more easily than was either endotracheal tube, especially by novices. The cuffed tube was positioned more readily than was the uncuffed variant. All three devices emitted isoflurane. The concentrations measured at the oral commissure for the LMA (mean +/- standard error, 8.4 +/- 0.6 ppm) were modestly higher than those acquired for the cuffed (6.7 +/- 0.5 ppm) and uncuffed (6.3 +/- 0.4 ppm) endotracheal tubes; the difference between the LMA and uncuffed tube was significant (P = 0.012). Isoflurane was not detected in the operator's breathing zone. These data show that the uncuffed endotracheal tube (usually used to anesthetize birds and reptiles) and the pediatric LMA can be used in rabbits as readily as a cuffed tube. In addition, our findings indicate that tradeoffs will be required in selecting a delivery system for this species, as the easiest apparatus (the LMA) also emits the most isoflurane waste.

Anesthesia, Inhalation↗
PubMedDate not supplied

Simultaneous precise chemoradiation under inhalation anesthesia in an experimental mouse tumor model.

BACKGROUND: Performing radiobiological experiments under general anesthesia is, in many cases, superior to treatment in unanesthetized animals or with intraperitoneal (i.p.) anesthesia. This is especially true for experiments where highly fractionated treatment schedules are used. MATERIALS AND METHODS: An anesthesia system was employed to overcome several of the limitations associated with the use of pentobarbital and other i.p.-administered anesthetics in experimental radiotherapy. RESULTS: Several different experiments with a total of 152 mice were performed. The total of all anesthesia exposures amounted to approximately 1,520. The duration of anesthesia ranged from 3 to 5 min per session. No complications related to the anesthetic procedure were observed. CONCLUSION: The present anesthesia/irradiation setup is a simple, safe and perfectly reproducible system where even multiple fractionated treatments can be performed under anesthesia with excellent tolerance. Our system allows easy and fast handling and immobilization and thus reduces experimental times.

Anesthesia, Inhalation↗
PubMed1991

[Value of in vivo NMR spectroscopy in the study of cerebral metabolism under inhalation anesthesia].

NMR in vivo spectroscopy is one of the few methods available for non-invasive investigations of cerebral metabolism in animals and humans. 31P and 1H spectroscopy are particularly suitable for monitoring the cerebral energy metabolism by determining the cerebral levels of ATP, ADP, phosphocreatine (PCr), inorganic phosphate (Pi), lactate and intracellular pH (pHi). These techniques also seem to be suitable for studying the effects of anesthetics by directly comparing the anesthetized and unanesthetized states in the same subject. The effects of halothane and isoflurane on the changes elicited in the cerebral energy metabolism by experimental hypercapnia were investigated by in vivo NMR spectroscopy. Halothane was found to aggravate the decrease in PCr attributed to the shift in creatine kinase equilibrium induced by the cerebral acidosis associated to hypercapnia, while the level of cerebral ADP was decreased to a lesser extent than in unanesthetized animals. In contrast isoflurane did not modify the changes in cerebral energy metabolism elicited by hypercapnia except that the decrease in PCr was significantly slowed, suggesting a lower creatine kinase activity. These data indicate that isoflurane and halothane act by two different mechanisms to produce a decrease in oxygen consumption. Halothane could interfere with oxidative metabolism by disturbing ATP metabolism, while isoflurane could decrease oxygen consumption by a general sedative action, slowing both cerebral functional activity and cerebral energy homeostasis.

Anesthesia, Inhalation↗
PubMed1990

[Potentiation of nondepolarizing muscle relaxants by nifedipine iv in inhalation anesthesia].

Calcium entry blockers are now widely used in the treatment of cardiovascular diseases. Nifedipine is established for the treatment of perioperative hypertension during anesthesia. Previous animal experiments have demonstrated that calcium entry blockers potentiate the neuromuscular response induced by nondepolarizing blocking drugs. Occasional observations in patients have led to the suggestion that this phenomenon may be of clinical significance. The interaction of nifedipine with nondepolarizing muscle relaxants in patients was assessed in a prospective clinical study. PATIENTS AND METHODS. Atracurium or vecuronium was administered for muscular relaxation in 44 patients anesthesized with isoflurane in nitrous oxide/oxygen. Monitoring included checks on noninvasive blood pressure, heart rate, pharyngeal temperature, tidal volume, end-tidal CO2 and neuromuscular transmission with a Datex ABM 100 Relaxograph ("train of four"). In the first study protocol atracurium was given to the patients after the intubation dose of 0.5 mg/kg in equal repetition doses of 0.2 mg/kg whenever T1 reached 25%. In 12 patients with the second repetition dose 1 mg nifedipine was injected i.v. The duration of neuromuscular depression with nifedipine until T1 reached 25% again was compared with the duration without nifedipine in the same patient. In the second protocol, constant neuromuscular blockade was accomplished in 11 patients by administration of atracurium or vecuronium at a constant perfusion rate at a level of 75% twitch depression. After 15 min of stable neuromuscular blockade 1 mg nifedipine was injected. In the third study protocol, 1 mg nifedipine i.v. was given at the end of anesthesia when the patients began to breathe spontaneously (T1 was at least 25%). RESULTS. In each patient there was a significant prolongation of neuromuscular blockade from 29 min +/- 6 min up to 40 min +/- 8 min when nifedipdine was given with the second repetition dose (P less than 0.001). During continuous relaxation with constant neuromuscular depression nifedipine increased the neuromuscular blockade from 75% up to 90% +/- 4% (P less than 0.05). In patients with spontaneous breathing and fading but still existing neuromuscular blockade nifedipine injection resulted in hypoventilation. The cardiovascular effects of 1 mg nifedipine, although significant, attained no clinically relevant values. CONCLUSIONS. Our results confirm previous assumptions of synergistic effects of neuromuscular blocking drugs and nifedipine in patients. This synergistic effect includes both duration and intensity of neuromuscular blockade. In the postoperative period patients may be endangered by nifedipine therapy if recovery from the neuromuscular depression is not complete.

Adult↗
PubMed1990

Bilateral arytenoid cartilage paralysis after inhalation anesthesia in a horse.

An 8-year-old Quarter Horse gelding was anesthetized for surgical exploration and debridement of a chronic draining wound in the intermandibular space. Anesthesia was without complication other than persistently low PaO2. Severe airway obstruction was evident immediately after extubation, requiring tracheostomy. Endoscopic diagnosis was bilateral arytenoid paralysis, which gradually resolved over the next 7 days. Compression, trauma, or tension of the recurrent laryngeal nerves are the postulated causes of idiopathic laryngeal hemiplegia in horses. The extremely extended position of the head and neck during anesthesia, perhaps compounded by low arterial oxygen content, may have resulted in a hypoxemic insult to the recurrent laryngeal nerves and caused bilateral arytenoid paralysis in this horse.

Anesthesia, Inhalation↗
PubMed1989

Alterations in host defense associated with inhalation anesthesia and blood transfusion.

Anesthesia and blood transfusions have been demonstrated to impair immune function. The present study evaluated whether these impairments led to increased susceptibility to infectious complications in two animal models. Both transfusions and anesthesia (methoxyflurane) were found to increase susceptibility to peritoneal Escherichia coli infections. This susceptibility increased with time after the transfusions but decreased with time after anesthesia. Neither transfusions nor anesthesia altered susceptibility to an intravenous Escherichia coli challenge in rats.

Anesthesia, Inhalation↗
PubMed1989

[Application of the shuttle system in inhalation anesthesia in horses and ponies].

Using the semi-closed to-and-fro system, oxygen-halothane anaesthesia was produced in horses and ponies. It is concluded that the system described enables the equine veterinary practitioner to carry out moderately prolonged surgery (up to approximately 120 minutes) by a justifiable and relatively safe method.

Anesthesia, Inhalation↗