Comparison of ketamine and S(+)-ketamine, with romifidine and diazepam, for total intravenous anesthesia in horses

Objective To compare the quality of induction and recovery, degree of muscle relaxation, clinically apparent potency and cardiopulmonary effects of racemic ketamine or S(+)-ketamine when used for total intravenous anesthesia in horses. Study design Prospective randomized clinical trial Animals Sixteen healthy stallions (323 +/- 99 kg), with a mean age of 6.2 years, undergoing castration. Methods Horses were pre-medicated with romifidine IV, 15 minutes before induction of anesthesia. Each animal was then randomly allocated to receive either diazepam and ketamine (DK) or diazepam and S(+)-ketamine (DKS) at similar doses to induce anesthesia. For maintenance of anesthesia, 1/4 of the initial bolus of ketamine alone or S(+)-ketamine alone was administered, as required. Heart rate (HR), respiratory rate (RR) and systolic blood pressure were measured before and at 10-minute intervals during recumbency. Time from induction to lateral recumbency, time from induction to first additional dose, time from last additional dose to return to sternal posture and time from last additional dose to standing were recorded, and a subjective evaluation of quality of induction, endotracheal intubation, muscle relaxation and quality of recovery was recorded. Results The quality of the induction and duration of anesthesia were similar in both groups. HR, RR and systolic blood pressure were not significantly different between groups. Although some animals which received DKS showed some minor excitatory effects (25% of them) during the induction of anesthesia, these animals received 32% fewer doses for the maintenance of anesthesia and the recovery scores were better. Conclusions and clinical relevance S(+)-ketamine showed some advantages over racemic ketamine, such as less anesthetic agent being required and better overall recovery from anesthesia. Further studies are needed to obtain the optimum induction dose for the S(+)-ketamine.

A Novel Approach to Intraoral Mandibular Nerve Anesthesia: Changing Reference Planes in the Gow-Gates Block Technique

Purpose: The Gow-Gates technique is said to have several advantages over traditional techniques to achieve mandibular nerve anesthesia; however, its routine use is quite limited, mainly due to complications during visual alignment of reference landmarks. The purpose of this study was to verify the validity and accuracy of a new method to reach the injection site. Material and Methods: Fifteen magnetic resonance images were captured. Distances from the ideal injection point in the condylar neck (puncture ideal) to the injection points located in the a and 0 plane intersection (Puncture Gow-Gates and puncture modified) were measured and compared. Results: Positive and significant (P <= .003) Pearson correlations between landmarks and injection points confirmed the validity of the modified technique. Paired t test showed that the segment line puncture ideal-puncture modified, 5.17 mm, was 3 times shorter (P < .001) than the segment line puncture ideal-puncture Gow-Gates, 17.91 mm. As calculated by linear regression, establishing the injection point of the modified technique depended only on the anteroposterior and lateromedial condyle positions. Conclusions: The modified technique proved to be valid and precise and has a determined and an effective injection site. (C) 2009 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 67:2609-2616, 2009

Nonlinear dynamics of the patient’s response to drug effect during general anesthesia

In today’s healthcare paradigm, optimal sedation during anesthesia plays an important role both in patient welfare and in the socio-economic context. For the closed-loop control of general anesthesia, two drugs have proven to have stable, rapid onset times: propofol and remifentanil. These drugs are related to their effect in the bispectral index, a measure of EEG signal. In this paper wavelet time–frequency analysis is used to extract useful information from the clinical signals, since they are time-varying and mark important changes in patient’s response to drug dose. Model based predictive control algorithms are employed to regulate the depth of sedation by manipulating these two drugs. The results of identification from real data and the simulation of the closed loop control performance suggest that the proposed approach can bring an improvement of 9% in overall robustness and may be suitable for clinical practice.

Nonlinear dynamics of the patient’s response to drug effect during general anesthesia

In today’s healthcare paradigm, optimal sedation during anesthesia plays an important role both in patient welfare and in the socio-economic context. For the closed-loop control of general anesthesia, two drugs have proven to have stable, rapid onset times: propofol and remifentanil. These drugs are related to their effect in the bispectral index, a measure of EEG signal. In this paper wavelet time–frequency analysis is used to extract useful information from the clinical signals, since they are time-varying and mark important changes in patient’s response to drug dose. Model based predictive control algorithms are employed to regulate the depth of sedation by manipulating these two drugs. The results of identification from real data and the simulation of the closed loop control performance suggest that the proposed approach can bring an improvement of 9% in overall robustness and may be suitable for clinical practice.

Anesthesia for Ex Utero Intrapartum Treatment: Renewed Insight on a Rare Procedure

The ex utero intrapartum treatment is a rare surgical procedure performed in cases of expected postpartum fetal airway obstruction. The technique lies on a safe establishment of a patent airway during labor in anticipation of a critical respiratory event, without interrupting maternal-fetal circulation. Anesthetic management is substantially different from that regarding standard cesarean delivery and its main goals include uterine relaxation, fetal anesthesia and preservation of placental blood flow. We present the case of an ex utero intrapartum treatment procedure performed on a fetus with a large cervical lymphangioma and prenatal evidence of airway compromise. Modifications to the classic ex utero intrapartum treatment management strategies were successfully adopted and will be discussed in the following report.

Prostate innervation and local anesthesia in prostate procedures

The nerve supply of the human prostate is very abundant, and knowledge of the anatomy contributes to successful administration of local anesthesia. However, the exact anatomy of extrinsic neuronal cell bodies of the autonomic and sensory innervation of the prostate is not clear, except in other animals. Branches of pelvic ganglia composed of pelvic (parasympathetic) and hypogastric (sympathetic) nerves innervate the prostate. The autonomic nervous system plays an important role in the growth, maturation, and secretory function of this gland. Prostate procedures under local anesthesia, such as transurethral prostatic resections or transrectal ultrasound-guided prostatic biopsy, are safe, simple, and effective. Local anesthesia can be feasible for many special conditions including uncomplicated prostate surgery and may be particularly useful for the high-risk group of patients for whom inhalation or spinal anesthesia is inadvisable.

Safest level of tricaine methanesulfonate (ms-222) to induce anesthesia in juveniles of Matrinxã, Brycon cephalus

The use of MS-222 as an anesthetic for matrinxã juveniles was investigated. At dosage of 100 mg/L or lower fish did not achieve a complete anesthesia state. At 150 mg/L, MS-222 induced anesthesia within 36 seconds and recovered from a 10 minutes period of anesthesia within 5.2 min. Higher concentrations (200, 250 and 300 mg/L) anesthetized fish in lesser times, with the offset of mortality (16.7 and 33.3%) at the 200 and 300 mg/L MS-222 doses, respectively. The only significant differences observed in the hematological parameters, was for the glucose values in fish anesthetized with 250 and 300 mg/L. From the results, the recommended dose of MS-222 for handling matrinxã juveniles is 150 mg/L.

Potential implications of ketamine anesthesia on zebrafish behavior

Dissertação de mestrado integrado em Psicologia

Myocardial Revascularization Surgery with Regional Anesthesia Without an Endotracheal Tube in Conscious Patients

OBJECTIVE: To report initial experience with myocardial revascularization surgery (MRS) performed on patients who were totally awake and without an endotracheal tube.METHODS: Between January 1994 and May 2001, 272 patients underwent MRS without extracorporeal circulation. In 24, the operations were performed without the use of an endotracheal tube and with the patients totally awake and breathing normally. The age ranged from 51-75 years with the predominant male sex. Epidural thoracic administratios of the anesthesia was performed. Surgery was performed through a habitual anterolateral thoracotomy. During the entire procedure, the left lung remained partially collapsed.RESULTS: The 24 patients progressed well through the surgery. Pneumothorax time ranged from 70-190 minutes. No electrocardiographic, echocardiographic, or enzymatic alterations occurred that characterized pre- and postoperative infarcts. Twenty-three patients were stable enough to be released after 24 hours.CONCLUSION: This technique could be performed on an large number of selected patients. However, more experience is necessary.

Anesthésie locale par tumescence [Tumescent local anesthesia].

Tumescent anesthesia is a local anesthesia produced by the infiltration of a large volume of very dilute anesthetic solution into the subcutaneous tissue. Many surgical procedures (liposuction, facelift, varicose vein surgery, etc.), which were previously performed under general or locoregional anesthesia, can now be achieved with local tumescent anesthesia. This type of anesthesia has many advantages: reduction of both anesthetic risks and surgical complications (bleeding, hematoma), prolonged anesthesia reducing the need for postoperative analgesia, and costs reduction because all these surgical procedures can be performed on an outpatient basis.

The effects of sevoflurane and halothane anesthesia on cerebral blood flow velocity in children.

We compared cerebral blood flow velocity during anesthesia with sevoflurane and halothane in 23 children admitted for elective surgery (age, 0.4-9.7 yr; median age, 1.9 yr; ASA physical status I-II). Inhaled induction was performed in a randomized sequence with sevoflurane or halothane. Under steady-state conditions, cerebral blood flow velocity (systolic [V(s)], mean [V(mn)], and diastolic [VD]) were measured by a blinded investigator using transcranial pulsed Doppler ultrasonography. The anesthetic was then changed. CBFV measurements were repeated after washout of the first anesthetic and after steady-state of the second (equivalent minimal alveolar concentration to first anesthetic). The resistance index was calculated. VD and V(mn) were significantly lower during sevoflurane (V(mn) 1.35 m/s) than during halothane (V(mn) 1.50 m/s; P = 0.001), whereas V(s) was unchanged. The resistance index was lower during halothane (P < 0.001). Our results indicate lower vessel resistance and higher mean velocity during halothane than during sevoflurane. IMPLICATIONS: The mean cerebral blood flow velocity is significantly decreased in children during inhaled anesthesia with sevoflurane than during halothane. This might be relevant for the choice of anesthetic in children with risk of increased intracranial pressure, neurosurgery, or craniofacial osteotomies.

Anesthesia of Biomphalaria spp. (Mollusca, Gastropoda): sodium pentobarbital is the drug of choice

The anesthetic effect of some water-soluble anesthesic or narcotic drugs currently used in mice was tested in molluscs of the Biomphalaria genus. Sodium thiopental was very toxic to the snails resulting in high rates of mortality in all the treatment schedules tested. Cetamine base, at concentration of 0.25 mg/ml of water, resulted in partial snail anesthesia (40% of snails were anesthetized) only after 20 h of exposition. The association of Cetamine base with Tiazine chloridrate did not improve the anesthesic effect, and higher concentrations of these drugs were toxic to the snails. Sodium pentobarbital at 0.4 mg/ml in water for 8 h was the best treatment schedule to anesthetize Biomphalaria snails. In this schedule, the snails were anesthetized without any toxic effect. The procedure provides a powerful tool for in vivo studies that demande a complete state of snail anesthesia.

Obstetric analgesia and anesthesia in Switzerland in 2007

Introduction: The last twenty years has witnessed important changes in the field of obstetric analgesia and anesthesia. In 2007, we conducted a survey to obtain information regarding the clinical practice of obstetric anesthesia in our country. The main objective was to ascertain whether recent developments in obstetric anesthesia had been adequately implemented into current clinical practice. Methodology: A confidential questionnaire was sent to 391 identified wiss obstetric anesthetists. The questionnaire included 58 questions on 5 main topics: activity and organization of the obstetric unit, practice of labor analgesia, practice of anesthesia for caesarean section, prevention of aspiration syndrome, and pain treatment after cesarean section. Results: The response rate was 80% (311/391). 66% of the surveyed anesthetists worked in intermediate size obstetric units (500-1500 deliveries per year). An anesthetist was on site 24/24 hours in only 53% of the obstetric units. Epidural labor analgesia with low dose local anesthetics combined with opioids was used by 87% but only 30% used patient controlled epidural analgesia (PCEA). Spinal anesthesia was the first choice for elective and urgent cesarean section for 95% of the responders. Adequate prevention of aspiration syndrome was prescribed by 78%. After cesarean section, a multimodal analgesic regimen was prescribed by 74%. Conclusion: When comparing these results with those of the two previous Swiss surveys [1, 2], it clearly appears that Swiss obstetric anesthetists have progressively adapted their practice to current clinical recommendations. But this survey also revealed some insufficiencies: 1. Of the public health system: a. Insufficient number of obstetric anesthetists on site 24 hours/24. b. Lack of budget in some hospitals to purchase PCEA pumps. 2. Of individual medical practice: a. Frequent excessive dosage of hyperbaric bupivacaine during spinal anesthesia for cesarean section. b. Frequent use of cristalloid preload before spinal anesthesia for cesarean section. c. Frequent systematic use of opioids when inducing general anesthesia for cesarean section. d. Fentanyl as the first choice opioid during induction of general anesthesia for severe preeclampsia. In the future, wider and more systematic information campaigns by the mean of the Swiss Association of Obstetric Anesthesia (SAOA) should be able to correct these points.