Increased success of blind nasotracheal intubation through the use of nasogastric tubes as a guide.
We were able to improve the success rate of blind nasotracheal intubation by using nasogastric tubes as a guide during intubation, first, for passing the endotracheal tube through the nasal cavity, and second, passing it from the pharynx to the larynx. By adding both sedation by modified neuroleptanalgesia (NLA) and topical and transtracheal administration of lidocaine, our technique became safer and smoother. We have completed 36 cases without accident, with an average time for intubation of 8.25 min. The Rush spiral tube was thought to be the most suited to this form of intubation because of the 90 degrees cut of its tip, its high-volume cuff, and its flexibility in all directions. These features are useful for hearing breath sounds, raising the tip of the tube by inflation of the cuff, and advancing the tube in a turning motion. (+info)
Relationship between EEG potentials and intracellular activity of striatal and cortico-striatal neurons: an in vivo study under different anesthetics.
The functions of the basal ganglia are achieved through excitation of striatal output neurons (SONs) by converging cortical glutamergic afferents. We assessed the relationship between different patterns of activity in cortico-striatal (C-S) cells and the electrical behavior of SONs in vivo. Intracellular activities of rat C-S neurons in the orofacial motor cortex and of SONs, located in the projection field of this cortical region, were recorded under different anesthetics, which generate various temporal patterns of cortical activity. A surface electroencephalogram (EEG) of the orofacial motor cortex was simultaneously performed with intracellular recordings and EEG waves were used as correlates of a coherent synaptic activity in cortical neurons. Under barbiturate anesthesia C-S neurons showed rhythmic (5--7 Hz) supra-threshold depolarizations in phase with large amplitude EEG waves. The correlative activity of SONs was characterized by large amplitude oscillation-like synaptic depolarizations that could trigger action potentials. Under ketamine-xylazine anesthesia C-S neurons exhibited a step-like behavior consisting of depolarizing plateaus (up states), leading to multiple spike discharges, interrupted by hyperpolarizing periods (down states). The related activity of SONs was step-like membrane potential fluctuations with firing confined to the early part of the striatal up state. In C-S neurons and SONs up states coincided with slow recurrent EEG waves (approximately 1 Hz). Finally, under neurolept-analgesia an apparently disorganized EEG activity was associated with a lack of rhythmic discharge in C-S neurons. This uncorrelated activity in C-S neurons resulted in an absence of spontaneous firing as well as of large amplitude synaptic depolarizations in SONs. In the present study we demonstrate that SONs shape their input-output relationship by filtering out uncorrelated synaptic activity and that a minimal synchronization in the cortico-striatal afferents is required to produce significant synaptic depolarization in SONs. (+info)
Neuroleptanalgesia and extracapsular cataract extraction.
Peribulbar and retrobulbar anaesthesia are commonly used techniques in cataract extraction. They offer satisfactory analgesia and akinesia but serious complications although uncommon are consistently reported. Intravenous sedation combined with a facial nerve block offers an alternative method of anaesthesia. This is a retrospective study of patients who underwent extracapsular cataract extraction using this technique between 1 January 1986 and 1 September 1990. The operating conditions were judged to be very suitable with minimal peroperative complications. The postoperative ocular complication rate was low (minimum follow-up 3 months) and no serious medical complications were noted: 93.8% of patients achieved 6/12 vision or better. This study demonstrates that it is possible to achieve satisfactory ocular analgesia and akinesia during cataract extraction under local anaesthesia without the use of a periocular injection. (+info)
Postoperative impairment of cognitive function in rats: a possible role for cytokine-mediated inflammation in the hippocampus.
BACKGROUND: Postoperative cognitive dysfunction is being increasingly reported as a complication. The authors investigated the role of cytokine-mediated inflammation within the central nervous system in the development of cognitive dysfunction in a rat model. METHODS: Adult rats were subjected to neuroleptic anesthesia (20 microg/kg fentanyl plus 500 microg/kg droperidol, intraperitoneal) for splenectomy or no surgery. On postanesthetic days 1, 3, and 7, cognitive function was assessed in a Y maze. To evaluate the immune response in the hippocampus, the authors measured glial activation, as well as transcription and expression of key proinflammatory cytokines interleukin 1beta and tumor necrosis factor alpha. To determine propensity for apoptosis, they measured expression of Bax and Bcl-2. RESULTS: Cognitive function in splenectomized animals was impaired at days 1 and 3 after surgery compared with cognitive function in nonanesthetized rats. At all times, anesthetized rats that were not subjected to surgery were no different from control rats. Glial activation was observed in the hippocampus only in splenectomized rats at postsurgery days 1 and 3. Interleukin-1beta messenger RNA (mRNA) was significantly increased at postsurgery days 1 and 3, with an increase in protein expression detected on day 1. There was a significant increase in tumor necrosis factor-alpha mRNA on day 1 after surgery, although this was not associated with an increase in protein expression. The ratio of Bcl-2:Bax was significantly decreased in the splenectomized animals. CONCLUSION: These results suggest that splenectomy performed during neuroleptic anesthesia triggers a cognitive decline that is associated with a hippocampal inflammatory response that seems to be due to proinflammatory cytokine-dependent activation of glial cells. (+info)
Measurement of cerebral blood flow and volume with positron emission tomography during isoflurane administration in the hypocapnic baboon.
Using positron emission tomography, cerebral blood flow (CBF) and cerebral blood volume (CBV) were measured after the addition of isoflurane (1.3 vols %, end-tidal concentration) to neuroleptanesthesia (fentanyl/droperidol) in hypocapnic baboons. The study was designed to determine whether isoflurane, when administered during hypocapnia, acted as a cerebral vasodilator to increase either CBF or CBV. Mean arterial pressure was maintained within 10% of preisoflurane levels with an angiotensin infusion. In the first protocol (A), CBF and CBV were measured as close together in time as possible in order to detect divergent effects of isoflurane on these variables. When PaCO2 was reduced from 40 mmHg to 25 mmHg, CBF decreased from 44 +/- 4 to 31 +/- 4 ml.100 g-1.min-1 (P less than 0.05) and CBV decreased from 3.1 +/- 0.3 to 2.6 +/- 0.3 ml/100 g (P less than .05). Neither CBF nor CBV was significantly changed by the addition of isoflurane. In the second protocol (B), serial CBV scans were performed frequently during the addition of isoflurane in a fashion designed to detect transient changes in CBV at the time isoflurane was first added to the breathing circuit. Induction of hypocapnia again reduced CBV from 3.1 +/- .3 to 2.7 +/- .2 ml/100 g, (P less than .05) and addition of isoflurane did not change CBV. From these results the authors conclude that in the normal hypocapnic baboon the addition of 1.3% isoflurane does not significantly change cerebral blood flow or volume. (+info)
The effect of ozone on reactivity of upper and lower airways in guinea-pigs.
1. The effect of ozone inhalation on the responsiveness of upper and lower airways to histamine was examined in guinea-pigs. 2. The exposure of conscious guinea-pigs to 3.5 p.p.m. ozone for 30 min rendered their lower airways 2-3 fold more sensitive to the bronchoconstrictor action of i.v. histamine, as assessed subsequently under anaesthesia. 3. The development of lower airway hyperreactivity was not modified by bilateral cervical vagotomy or pretreatment with BW 755C, FPL 55712 or SC-39070. 4. Under the conditions used, ozone exposure produced a mild inflammatory response as monitored by bronchoalveolar lavage, characterized by epithelial damage and prostaglandin E2 generation, but no cellular infiltration or oedema. 5. In contrast to the lower airways, upper airway resistance was reduced by i.v. histamine. This response was not affected by ozone exposure. 6. Isolated tracheal preparations taken from ozone-exposed guinea-pigs were not significantly more sensitive to histamine than control tissues. 7. The mechanism of hyperreactivity in this model is unknown but does not depend on leukotriene generation or a vagal reflex. (+info)
Comparison of two intravenous sedation techniques for percutaneous radio frequency trigeminal rhizotomy. A pilot study.
Conscious sedation, as used in dentistry and oral surgery, has been used satisfactorily to manage patients undergoing the intense pain encountered in radio frequency trigeminal rhizotomy for tic douloureux. The pain produced by this procedure cannot be blocked by local anesthesia. General anesthesia cannot be used because of the need for sensory testing in an awake, cooperative patient. Conscious sedation using alphaprodine, hydroxyzine, methohexital, and intensive behavioral modification was compared with a neuroleptic intravenous sedation technique using droperidol, fentanyl, and thiopental. Patients managed with conscious sedation were found to be more amnestic for the pain of surgery, a difference that persisted six months later. (+info)
A comparative study of conventional premedication (pethidine, promethazine, and atropine) and neuroleptanalgesia (droperidol and phenoperidine) for peroral endoscopy.
A double blind comparison of conventional premedication (pethidine, promethazine, and atropine) and neuroleptanalgesia (droperidol and phenoperidine) failed to demonstrate any difference in either the comfort of the patient or ease of instrumentation in 70 upper gastrointestinal tract endoscopies. Further trials are needed before conventional premedication is abandoned. (+info)