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Results for “Balanced Anesthesia”

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At least 577 records · Page 32Linked to original sources

PubMedDate not supplied

Diluting lidocaine and mepivacaine in balanced salt solution reduces the pain of intradermal injection.

BACKGROUND AND OBJECTIVES: Intradermal injection of local anesthetics prior to percutaneous needle insertion is often painful. This study evaluated the effect of diluting lidocaine and mepivacaine with balanced salt solution on perception of pain on intradermal injection. METHODS: Twenty healthy volunteers were each intradermally injected with six solutions in random order. These solutions were: normal saline (NS), 0.9% benzyl alcohol in NS, 0.2% lidocaine in NS, 0.2% lidocaine in balanced salt solution, 0.2% mepivacaine in NS, and 0.2% mepivacaine in balanced salt solution. Discomfort of each injection was reported on a 0-2 pain scale. The degree of anesthesia at each site was evaluated by pinprick every minute for 20 minutes. RESULTS: Benzyl alcohol and lidocaine and mepivacaine in balanced salt solution caused the least injection pain. However, mepivacaine in NS and NS alone caused the most pain. The anesthetic effect of benzyl alcohol was judged adequate for only 4 minutes whereas both lidocaine and mepivacaine in either NS or balanced salt solution gave adequate anesthesia for at least 15 minutes. CONCLUSIONS: The dilution of lidocaine and mepivacaine with balanced salt solution produces a solution that is both painless on injection and of moderate duration.

Adult↗

PubMed1975

[Hypothermia during general anesthesia and methods of its prevention].

In the article great attention is paid to prophylaxis of hypothermal disturbances in heat exchange during the process of general anesthesia, it comprises the use of complex methods of protection against hypothermia. It is the authors' opinion that the state of thermal balance should be followed as carefully during general anesthesia as hemostatic indices, since normothermia improved considerably the clinical course of narcosis and postoperative period, as well.

Adolescent↗

PubMed2006

Postoperative infusion of amino acids induces a positive protein balance independently of the type of analgesia used.

BACKGROUND: Net loss of body protein is a prominent feature of the catabolic response to surgical tissue trauma. Epidural analgesia with hypocaloric dextrose has been demonstrated to attenuate leucine oxidation but was unable to make protein balance positive. The current study was set to determine whether an infusion of amino acids on the second day after colon surgery would revert the catabolic state and promote protein synthesis while maintaining glucose homeostasis in patients receiving epidural analgesia as compared with patient-controlled analgesia with morphine (PCA). METHODS: Sixteen patients undergoing colorectal surgery were randomly assigned to receive epidural blockade or PCA as analgesic techniques and underwent a 6-h stable isotope infusion study (3 h fasted, 3 h fed) on the second postoperative day. Whole body glucose kinetics and protein turnover were measured using [6,6-2H2]glucose and l-[1-13C]leucine as tracer. RESULTS: The infusion of amino acids caused a decrease in endogenous glucose rate of appearance in both groups (P < 0.05), with greater changes in the PCA group (P < 0.05). Administration of amino acids suppressed the appearance of leucine from protein breakdown in both groups (P < 0.05), although the decrease was greater in the PCA group (P < 0.05). Leucine oxidation increased in both groups (P < 0.05), with greater change in the epidural group (P < 0.05). Protein synthesis increased to the same extent in both groups (P < 0.05). Protein balance became positive after the infusion of amino acids, and the effect was greater in the PCA group (P < 0.05). CONCLUSIONS: Infusion of amino acids decreased the endogenous glucose production and induced a positive protein balance independent of the type of anesthesia provided, although such effects were greater in the PCA group.

Adult↗

PubMed1982

Respirators and respiratory care.

The intellectual and technological roots of respirators and respiratory care may be traced back hundreds of years. The clinical evolution has taken the better part of a century, and it has been most closely linked to the development of open-chest surgery. Resuscitation and the treatment of poliomyelitis also have contributed ideas and technology to this evolution. If its successful performance had depended only on respirators, open-chest surgery would have become clinical routine 50-80 years ago. In fact, many factors had to be under control, many modes of treatment had to be available, before the breakthrough in open-chest surgery could occur. The most important factor may have been the effective control of sepsis and hemorrhage. Open-chest surgery forced the change from single-agent deep anesthesia with spontaneous ventilation to a balanced technique, using multiple drugs or agents, with controlled ventilation. Open-chest surgery also necessitated that physicians specialize in anesthesiology. Scandinavian scientists and physicians have contributed greatly to the field of respirators and respiratory care, as has the specialty of anesthesiology.

Anesthesiology↗

PubMed1989

Is midazolam a dangerous drug?

Midazolam can be used to achieve anxiolysis, to provide conscious sedation with anterograde amnesia during operations performed under local or regional anesthesia, to induce general anesthesia, and as part of a balanced anesthetic. Understanding the pharmacologic properties and potential adverse side effects of any drug is necessary in order to dose and monitor patients effectively. When used with vigilance, appropriate patient monitoring, and slow, careful titration to desired effect, midazolam is an extremely useful and safe medication for both inpatients and outpatients.

Anxiety↗

PubMed2006

Blood gas changes in patients undergoing laryngeal microsurgery.

BACKGROUND: The aim of this prospective, single-blind study was to assess the variations in the blood levels of PaO(2), PaO(2)/FiO(2), PaCO(2), and acid-base balance of patients undergoing laryngeal microsurgery under general anesthesia using small-bore endotracheal tubes. METHODS: 25 male patients were intubated with endotracheal tubes of 5.5-mm-inner diameter and fifteen female patients were intubated with endotracheal tubes of 5-mm-inner diameter during surgery. PaO(2)/FiO(2), PaO(2), PaCO(2), percentage saturation of O(2) and HCO(3), and pH levels were monitored before surgery and at 15-min intervals during laryngeal microsurgery. Respiratory function's values (dead space, peak inspiratory pressure (PIP) and dynamic compliance) were recorded every 15 min throughout laryngeal microsurgery. RESULTS: No significant differences were observed between the pre- and intra-operative values of percentage saturation of O(2), PaO(2)/FiO(2) and HCO(3) until 120th min. There was no significant difference in respiratory function's values intraoperatively. Under anesthesia, PaO(2) levels significantly increased when compared with preoperative values. Another significant increase was observed in PaCO(2) levels after the 60th min. However, compared with preoperative values, pH levels significantly decreased under anesthesia at the 105th and 120th min. CONCLUSION: Laryngeal microsurgery under general anesthesia can be performed using small-bore endotracheal tubes. This is not likely to have any adverse effects on a patient's blood gases and acid-base balance unless the operation lasts longer than 105 min.

Acid-Base Equilibrium↗

PubMed1992

[Neuropsychologic effects of anesthesia in the elderly].

Two anaesthetic techniques, the general balanced anaesthesia and the spinal one, have been compared in relation to their effects on neuropsychological functions as assessed by a neuropsychological test battery. Seventeen patients, who underwent different kinds of operations, have been kept under observation and checked up from a neuropsychological point of view 3 days before (time A) and 7 and 30 days after the operation (respectively time B and time C). No statistical significant differences in relation to the two anaesthetic techniques were found when comparing A, B and C assessment times. A decrease in cognitive performance at time B and a gradual return to basal condition were observed in patients who underwent general anaesthesia. Nevertheless the lack of statistical significance of the observed data leads to the need for further investigation.

Age Factors↗

PubMed2007

Etomidate reduces initiation of backpropagating dendritic action potentials: implications for sensory processing and synaptic plasticity during anesthesia.

Anesthetics may induce specific changes that alter the balance of activity within neural networks. Here we describe the effects of the GABA(A) receptor potentiating anesthetic etomidate on sensory processing, studied in a cerebellum-like structure, the electrosensory lateral line lobe (ELL) of mormyrid fish, in vitro. Previous studies have shown that the ELL integrates sensory input and removes predictable features by comparing reafferent sensory signals with a descending electromotor command-driven corollary signal that arrives in part through parallel fiber synapses with the apical dendrites of GABAergic interneurons. These synapses show spike timing-dependent depression when presynaptic activation is associated with postsynaptic backpropagating dendritic action potentials. Under etomidate, almost all neurons become tonically hyperpolarized. The threshold for action potential initiation increased for both synaptic activation and direct intracellular depolarization. Synaptically evoked inhibitory postsynaptic potentials (IPSPs) were also strongly potentiated and prolonged. Current source density analysis showed that backpropagation of action potentials through the apical dendritic arborization in the molecular layer was reduced but could be restored by increasing stimulus strength. These effects of etomidate were blocked by bicuculline or picrotoxin. It is concluded that etomidate affects both tonic and phasic inhibitory conductances at GABA(A) receptors and that increased shunting inhibition at the level of the proximal dendrites also contributes to increasing the threshold for action potential backpropagation. When stimulus strength is sufficient to evoke backpropagation, repetitive association of synaptic excitation with postsynaptic action potential initiation still results in synaptic depression, showing that etomidate does not interfere with the molecular mechanism underlying plastic modulation.

Action Potentials↗

PubMedDate not supplied

[Materno-fetal acid-base equilibrium evaluation in parturients submitted to ketamine anesthesia (author's transl)].

In the present work ketamine was used as anesthetic during the labor in order to evaluate the effect of this anesthetic on the binominal fetus-mother. Two groups of parturients and their fetuses, were studied: 1) The experimental group, with 22 parturients and their fetuses submitted to ketamine anesthesia during the labord, and 2) The control group, with 20 parturients and their fetuses without any analgesic treatment during the labor. In 20 cases of the experimental group the anesthetic was injected during the delivery labor and the other two just before it. It were evaluated in the mother's blood the biochemical parameters of the acid-base balance and others collateral effects of the anesthesia; on the fetus's side the same parameters also and the cardiac frequency. The newborn were evaluated by Apgar Score during the first and fifth minutes of life. The incidence of the spontaneous delivery in the experimental group, was 78%; in 22% of these patients the forceps of relief was used. In 22 cases in which Ketamine was applied it were observed, the following events: elevation of the blood pressure (50%), perineum rigidness (18%), dreams and or hallucinations (18%), increase of the cardiac frequency (9%), apneia (4%) and nausea (4%). It was also observed an increase of uterine tonus an abolishment of abdominal press during the delivery labor, studied through the uterine electromyography register. It was noted after the Ketamine application a fall in the pH of the maternal peripherical venous blood, fetal skull blood and the pH of the blood of the umbilical vein. 22% of the newborns, from the experimental group, presented a depression in the first minute of life (Apgar less than or equals to 6). The pCO2 values in the blood of the umbilical artery were higher in the experimental group than in the control one.

Acid-Base Equilibrium↗

PubMed1996

Anesthetic management of arteriovenous malformation: a case report.

This case illustrates the anesthetic management of radiographically assisted embolization and surgical excision of a large arteriovenous malformation (AVM). Excision resulted in significant blood loss and cerebral edema. This prompted the use of cerebral protection and induced hypotension. The patient was kept in a barbiturate coma postoperatively. On emergence from the barbiturates, the patient demonstrated elevated intracranial pressure and resolving deficits. She was discharged 3 weeks after surgery for rehabilitation. Arteriovenous malformations can compromise the cerebral parenchyma by mass effect, by hemorrhage, and by "stealing" blood from adjacent tissue. Subarachnoid hemorrhage (SAH) can result in sympathetic stimulation, hydrocephalus, meningeal irritation, fluid and electrolyte disturbances, and cerebral vasospasm. Excision may result in massive cerebral hemorrhage and edema as arterial pressures are abruptly normalized. Anesthetic management is guided by a full evaluation of the patient's pathophysiology and medical management. The anesthetist must understand the total impact of the AVM, compensatory responses, and the hazard of surgery and anesthesia. The goal is to achieve a balance in oxygen supply and demand at a pressure sufficient to perfuse the brain tissue without exceeding the pressure limits of compromised vasculature. This must be done while providing optimal brain relaxation for excision with minimal bleeding.

Adult↗

PubMed1989

Prediction and early diagnosis of acute myocardial ischemia during anesthesia: a critical review.

Adequate myocardial oxygenation is the result of a good balance between the myocardial oxygen supply and the oxygen demand. Recognition of an insufficient myocardial oxygenation is particularly difficult during general anesthesia because angina pectoris, one of the most reliable indicators of ischemia cannot be expressed. Therefore other indices must be used. Considerable interest but also controversy surrounds the question which routinely monitored determinant of myocardial oxygen supply and demand best predicts and diagnoses beginning myocardial ischemia. A thorough understanding of the sensitivity and the limitations of the different monitoring techniques is a must for every anesthetist dealing with patients with coronary artery disease. The present state of knowledge and the new trends appearing on this subject are reviewed.

Anesthesia, General↗

PubMedDate not supplied

Central vagal control of fentanyl-induced bradycardia during halothane anesthesia.

Six mongrel dogs were used to investigate the mechanism of action of fentanyl-induced bradycardia. With controlled acid-base balance and temperature, and under 1.0 to 1.2 percent endtidal halothane anesthesia, 5 and microgram/kg of IV fentanyl citrate were given sequentially 1 hour apart and heart rate (HR) followed for 60 minutes. A dose-related depression of HR followed both injections. One week later the same dogs were studied similarly, except that bilateral cervical vagotomies were performed before fentanyl was given. The decrease in HR was at most 10 percent of the decrease in HR observed in the innervated dogs. Serum fentanyl levels were comparable. The data indicate the majority of the chronotropic action of fentanyl involves vagal efferent impulses from the central nervous system.

Anesthesia, Inhalation↗

PubMed1976

[Changes of certain indicators of gas exchange and hemodynamics under conditions of long-term peridural anesthesia after lung resection].

A continuous peridural anesthesia after pulmonary resection was conducted in 200 patients aged from 3 to 72 years. The anesthesia would contribute to a prompt normalization of ventilatory indices and acid-base balance in early terms, it also improves hemodynamics. This method of postoperative anesthesia enabled the authors to reduce the number of tracheobronchial obturations in the surgical department from 8.4% to 5.1%.

Acid-Base Equilibrium↗

PubMed1997

Anesthetics alter relative contributions of NO and EDHF in rat cremaster muscle microcirculation.

The contributions of the vasodilators nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) were investigated in the rat cremaster muscle microcirculation during halothane, isoflurane, or ketamine anesthesia. After inhibition of prostaglandin synthesis with indomethacin, changes in diameter of fourth-order arterioles to acetylcholine (ACh) or bradykinin (BK) were studied in the presence or absence of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of NO synthase, and/or 20 mM K+, an inhibitor of EDHF action. L-NMMA inhibited ACh- and BK-induced vasodilation during isoflurane but not halothane or ketamine anesthesia. Superfusion of the muscle with buffer containing 20 mM K+ dilated arterioles. EDHF was responsible for most of the NO-independent response to ACh, because 20 mM K+ unmasked ACh-stimulated, NO-dependent relaxation during halothane or ketamine anesthesia. However, 20 mM K+ did not inhibit BK-induced vasodilation during halothane or ketamine anesthesia. Our data suggest that anesthetics can alter the balance between NO and EDHF vasodilation in the microcirculation and that NO-dependent mechanisms are enhanced and EDHF action inhibited during isoflurane anesthesia.

Abdominal Muscles↗

PubMed2004

Fifty years of general anesthesia in California oral and maxillofacial surgery.

In summary, the advances of the last half of the 20th century in general anesthesia delivery by oral and maxillofacial surgeons are the following: 1. Oral and maxillofacial surgeons in training are exposed to significantly more hospital general anesthesia training and in addition spent much of their residency training performing general anesthesia on outpatient dental patients undergoing dentoalveolar surgery. Training programs increased from one year to three years, then to four years and finally, many six-year programs were developed that award the MD degree during or following completion of the residency program. 2. Self-evaluation programs were initiated in the late 1960s and evolved into mandatory in-office evaluation by peer practitioners and later into state-regulated evaluation. These programs began in Southern California and spread to encompass the entire United States. 3. Intravenous ultra-fast acting barbiturate office anesthesia became very refined and several combination drug "balanced" techniques developed. 4. Benzodiazepines, first diazepam then midazolam were introduced and gained wide acceptance by the dental profession. 5. New synthetic narcotic agents were introduced, which give the oral surgeon another pain control and anesthesia supplement. The new agents were short acting but very effective for the period necessary to complete most office surgical procedures. Fentanyl is the prototype for these agents. 6. Monitoring devices were incorporated into practice, and currently all oral surgeons use the pulse oximeter, the electrocardiograph, and blood pressure monitoring devices. All of these monitors are required by the California general anesthesia regulations. 7. Propofol, an entirely new type of intravenous agent, was introduced and is used by more than half of oral surgeons reporting in a survey of drugs used in 2003. Propofol may be used by incremental injection or by continuous infusion incorporating an automatic infusion pump. 8. Sevoflurane, a potent inhalation anesthetic that has many properties of an ideal agent - rapid onset, potent, easily delivered by calibrated vaporizers, rapid emergence, infrequent postoperative nausea, and favorable acceptance by almost all patients about to undergo general anesthesia - is gaining acceptance and use by oral and maxillofacial surgeons.

Anesthesia, General↗

PubMed1993

[Oxidative stress in patients undergoing general anesthesia].

The alterations in the normal biological oxide-reductive balance can be due both to an increase of the plasmatic concentration of the free radicals and to the less of the protective mechanism. These conditions lead to damage to cellular structure by the mechanism of lipoperoxidation, particularly in the liver, in the kidney and in the central nervous system. In this study we have studied the lipoperoxidative effects of the use of anesthetic drugs.

Anesthesia, General↗

PubMed2002

Volume kinetic analysis of the distribution of 0.9% saline in conscious versus isoflurane-anesthetized sheep.

BACKGROUND: The distribution and elimination of 0.9% saline given by intravenous infusion has not been compared between the conscious state and during inhalational anesthesia. METHODS: Six adult sheep received an intravenous infusion of 25 ml/kg of 0.9% saline over 20 min in the conscious state and also during isoflurane anesthesia and mechanical ventilation. The distribution and elimination of infused fluid were studied by volume kinetics based on serial analysis of hemoglobin dilution in arterial blood and by mass balance that incorporated volume calculations derived from volume kinetic analysis and measurements of urinary volumes. RESULTS: The mass balance calculations indicated only minor differences in the time course of plasma volume expansion between the conscious and anesthetized states. However, isoflurane anesthesia markedly reduced urinary volume (median, 9 vs. 863 ml; P < 0.03). In conscious sheep, the central and peripheral volume expansion predicted by volume kinetics agreed well with the calculations based on mass balance. However, during isoflurane anesthesia and mechanical ventilation, calculation using volume kinetic analysis of the variable kr, an elimination factor that, in conscious humans and sheep, is closely related to urinary excretion, represented both urinary excretion and peripheral accumulation of fluid. This suggests that the previous assumption that kr approximates urinary excretion of infused fluid requires modification, i.e., kr simply reflects net fluid movement out of plasma. CONCLUSIONS: In both conscious and anesthetized, mechanically ventilated sheep, infusion of 0.9% saline resulted in minimal expansion of plasma volume over a 3-h interval. In conscious sheep, infused 0.9% saline was rapidly eliminated from the plasma volume by urinary excretion; in contrast, the combination of isoflurane anesthesia and mechanical ventilation reduced urinary excretion and promoted peripheral accumulation of fluid.

Algorithms↗

PubMed1994

Total intravenous anesthesia is best for neurological surgery.

We believe that today balanced TIVA represents the best anesthetic technique for neurological surgery. Freely acknowledging that this point of view is unproven (36) with regard to the hard criterion of patient outcome on leaving the hospital, we submit that the intermediate or surrogate criteria discussed make a convincing case for preferring TIVA to volatile-based anesthetic techniques. Until a study demonstrating hard outcome differences between the two techniques is achieved, we will continue to encourage the use of TIVA in neuroanesthesia, based on its practical (anesthetic depth, neuromonitoring, surgical field) and theoretical (homeostasis, metabolism, antinociception, neuroprotection) advantages.

Analgesics↗