Total Spinal Anesthesia Failure: Have You Assessed the Sensory Anesthesia in Sacral Dermatomes?

Intrathecal local anesthetic maldistribution is a well-known cause of spinal anesthesia failure (SAF). This could potentially result in sensory blockade restricted to the sacral dermatomes. We sought to determine the overall incidence of SAF and the role of sacral dermatomes in differentiating between total and partial failures. Of the 3111 spinals prospectively examined, 194 (6.2%) were classified as failures. Of the 72 presumed total failures based on the initial assessment, evaluation of the sacral dermatomes revealed sensory blockade in 32 (44%; 95% confidence interval, 32.7%-56.6%). Sacral dermatome assessment after SAF may be important in safely guiding subsequent anesthetic management.

The effects of subarachnoid administration of preservative-free S(+)-ketamine on spinal cord and meninges in dogs.

BACKGROUND: The N-methyl-d-aspartate receptor antagonist ketamine and its active enantiomer, S(+)-ketamine, have been injected in the epidural and subarachnoid spaces to treat acute postoperative pain and relieve neuropathic pain syndrome. In this study we evaluated the effects of a single dose of preservative-free S(+)-ketamine, in doses usually used in clinical practice, in the spinal cord and meninges of dogs. METHODS: Under anesthesia (IV etomidate (2 mg/kg) and fentanyl (0.005 mg/kg), 16 dogs (6 to 15 kg) were randomized to receive a lumbar intrathecal injection (L5/6) of saline solution of 0.9% (control group) or S(+)-ketamine 1 mg/kg(-1) (ketamine group). All doses were administered in a volume of 1 mL over a 10-second interval. Accordingly, injection solution ranged from 0.6% to 1.5%. After 21 days of clinical observation, the animals were killed; spinal cord, cauda equina root, and meninges were removed for histological examination with light microscopy. Tissues were examined for demyelination (Masson trichrome), neuronal death (hematoxylin and eosin) and astrocyte activation (glial fibrillary acidic protein). RESULTS: No clinical or histological alterations of spinal tissue or meninges were found in animals from either control or ketamine groups. CONCLUSION: A single intrathecal injection of preservative-free S(+)-ketamine, at 1 mg/kg(-1) dosage, over a concentration range of 6 to 15 mg/mL injected in the subarachnoid space in a single puncture, did not produce histological alterations in this experimental model.

The anatomy of the thoracic spinal canal investigated with magnetic resonance imaging.

BACKGROUND: We investigated, with magnetic resonance imaging, the distance of the dura mater to the spinal cord in patients without spinal or medullar disease at the 2nd, 5th, and 10th thoracic segments. METHODS: Fifty patients in the supine position underwent magnetic resonance imaging. Medial sagittal slices of the 2nd, 5th, and 10th thoracic segments were measured for the relative distances using the 1.5-T superconducting system (Gyroscan Intera, Philips Medical Systems, Best, the Netherlands). In 10 patients, the angles relative to the tangent at the insertion point on the skin were measured. RESULTS: The posterior dural-spinal cord distance is significantly greater at the midthoracic region (5th thoracic = 5.8 +/- 0.8 mm) than at the upper (2nd thoracic = 3.9 +/- 0.8 mm) and lower thoracic levels (10th thoracic = 4.1 +/- 1.0 mm) (P < 0.015). There were no differences between interspaces T2 and T10. There was no correlation between age and the measured distance between the dura mater and the spinal cord. The entry angle of the needle at T2 was 9.0 degrees +/- 2.5 degrees ; at T5, 45.0 degrees +/- 7.4 degrees ; and at T10, 9.5 degrees +/- 4.2 degrees . CONCLUSIONS: This study demonstrated that there is greater depth of the posterior subarachnoid space at the T2, T5, and T10 levels. The greater distance was found at T5.

[The anesthesiologist facing terminality: a survey-based observational study]. / O anestesiologista frente à terminalidade.

BACKGROUND AND OBJECTIVES: Advances in medicine, including anesthesiology and resuscitation, have made natural death increasingly rare. As a consequence, dysthanasia has become usual in a scenario for which there is not rationale. The present study aimed to assess the level of knowledge of Brazilian anesthesiologists on the principles of dysthanasia and orthothanasia. Thence, we studied the management preferences of these professionals, vis-à-vis those practices, as well as how medical school contributed to addressing death-related issues. METHOD: Quantitative approach, prospective and descriptive cohort that included 150 anesthesiologists, members of the Brazilian Society of Anesthesiology, and who were invited to participate by email. An online questionnaire containing 38 questions was prepared by the authors. The study was approved by the Instructional Research Ethics Committee. RESULTS: Anesthesiologists, although claiming to know dysthanasia and orthothanasia, mostly acquired knowledge outside medical school. If faced with their own end of care, or of a patient or a loved one, they prefer orthothanasia, to die at home, prioritizing dignity. However, the specialists claimed to have already practiced dysthanasia, even when orthothanasia was the choice management, which caused them negative feelings. Almost all respondents stated that they did not have practical training in undergraduate school on how to face end-of-life issues, although they felt capable of identifying it. Most were not aware of Federal Council of Medicine Resolution 1.805/06 that makes practicing orthothanasia feasible. Anesthesiologists' religion or the political-administrative region of residence had no effect on their preferences. CONCLUSIONS: Anesthesiologists claim to have knowledge on dysthanasia and orthothanasia, but prefer, in the face of a terminally ill patient, to practice orthothanasia, although dysthanasia is usual, and results in frustration and indignation. The medical school curriculum is unsatisfactory in addressing death-related issues.

Effects on mother and fetus of epidural and combined spinal-epidural techniques for labor analgesia.

OBJECTIVE: Epidural (EA) and combined spinal-epidural (CSE) techniques have both been utilized for labor analgesia. This study compared the effects on the mother and newborn of these techniques in labor analgesia and anesthesia. METHODS: Forty pregnant women received epidural analgesia with 15 mL of 0.125% ropivacaine (EA group) and 5 microg of sufentanil plus 2.5mg bupivacaine in the subarachnoid space (CSE group). Pain intensity, sensory blockade level, latency time, motor block intensity, labor analgesia duration, epidural analgesia duration, maternal hypotension, and pruritus were evaluated. The newborns were evaluated by Apgar and the neurological and adaptive capacity score (NACS) developed by Amiel-Tison. RESULTS: There were no significant statistical differences between groups for pain scores, latency time, sensory blockade level, and Apgar score. Motor block, labor analgesia duration, and epidural analgesia duration were greater in the CSE group, whose seven mothers had mild pruritus. The NACS were greater in the EA group after half, two, and 24 hours. Ninety five percent of EA group newborns and 60% of CSE group newborns were found to be neurologically healthy at the 24 hour examination. CONCLUSION: EA and CSE analgesia relieved maternal pain during obstetric analgesia, but CSE mothers had pruritus and a longer labor. Newborns of mothers who received epidural analgesia showed the best NACS.

Can an inflammatory reaction in the meninges, caused by spinal puncture through tattooed skin, evolve into adhesive arachnoiditis? An experimental model in rabbits.

BACKGROUND AND OBJECTIVES: As the number of people with tattoos has been increasing, anesthesiologists are more and more faced with the decision to perform a neuraxial blockage through tattooed skin. In this study, we evaluated the possibility of puncture through tattooed skin determines acute inflammatory changes in the meninges and spinal cord and later evolve into adhesive arachnoiditis. METHOD: Forty-two male rabbits were randomized into 3 groups of 14: G1, spinal puncture through non-tattooed skin and saline solution injection; G2, spinal puncture through tattooed skin and saline solution injection, captive for 30 days; G3, spinal puncture through tattooed skin and saline solution injection, captive for 360 days. The animals were anesthetized and ultrasound-guided spinal puncture was performed in the intervertebral spaces between S1 - S2. During the period of captivity, the animals were clinically assessed for sensitivity and motor function. After that, they were sacrificed and the lumbosacral portion of the spinal cord was excised for histological analysis. RESULTS: No histological changes were found on group 1. Eleven animals from group two presented with foci of perivascular lymphocytic inflammatory infiltrate in the pia mater and/or arachnoid. In Group 3, eight rabbits presented with inflammatory changes in the meninges, which were associated with thickening and/or adhesion of the pia mater and arachnoid in some cases and five rabbits presented only thickening of pia-mater. CONCLUSIONS: Spinal puncture through tattooed skin of rabbits can trigger acute inflammatory changes in the meninges and after a prolonged period of observation evolve into adhesive arachnoiditis.

Gastric mucosal perfusion in dogs: effects of halogenated anesthetics and of hemorrhage.

The gastrointestinal tract is one of the first organs affected by hypoperfusion during hemorrhagic shock. The hemodynamics and oxygen transport variables during hemorrhagic shock and resuscitation can be affected by the anesthetics used. In a model of pressure-guided hemorrhagic shock in dogs, we studied the effects of three halogenated anesthetics--halothane, sevoflurane, and isoflurane--at equipotent concentrations on gastric oxygenation. Thirty dogs were anesthetized with 1.0 minimum alveolar anesthetic concentration (MAC) of either halothane, sevoflurane, or isoflurane. A gastric tonometer was placed in the stomach to determine mucosal gastric CO(2) (PgCO(2)) and for the calculation of gastric-arterial PCO(2) gradient (PCO(2) gap). The dogs were splenectomized and hemorrhaged to hold mean arterial pressure at 40-50 mm Hg over 45 min and then resuscitated with the shed blood volume. Hemodynamics, systemic oxygenation, and PCO(2) gap were measured at baseline, after 45 min of hemorrhage, and at 15 and 60 min after blood resuscitation. Hemorrhage induced reductions of mean arterial pressure and cardiac index, while systemic oxygen extraction increased (p < .05), without significant differences among groups (p > .05). Halothane group showed significant lower PCO(2) gap values than the other groups (p < .05). After 60 min of shed blood replacement, all groups restored hemodynamics, systemic oxygenation, and PCO(2) gap to the prehemorrhage levels (p > .05), without significant differences among groups (p > .05). We conclude that halothane is superior to preserve the gastric mucosal perfusion in comparison to isoflurane and sevoflurane, in dogs submitted to pressure-guided hemorrhagic shock at equipotent doses of halogenated anesthetics.

Labor analgesia with ropivacaine added to clonidine: a randomized clinical trial.

CONTEXT AND OBJECTIVE: Previous studies have led to speculation that the association between ropivacaine and clonidine might be more effective than ropivacaine alone. We examined the maternal-fetal effects of two pharmacological approaches: a low dose of ropivacaine or a lower dose of ropivacaine plus clonidine for epidural analgesia during labor. DESIGN AND SETTING: Prospective study at Department of Anesthesiology, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista. METHODS: Thirty-two pregnant women in American Society of Anesthesiologists physical status I and II randomly underwent epidural analgesia using 15 ml of ropivacaine 0.125% (R group) or 15 ml of ropivacaine 0.0625% plus 75 microg clonidine (RC group). Pain intensity, sensory block level, latency time, motor block intensity, duration of labor analgesia and duration of epidural analgesia were evaluated. The newborns were evaluated using Apgar scores and the Amiel-Tison method (neurological and adaptive capacity score). RESULTS: There were no statistically significant differences between the groups regarding pain score, sensory block level, duration of epidural analgesia or Apgar score. The latency time, duration of labor analgesia and motor block were R group < RC group. The half-hour and two-hour neurological and adaptive capacity scores were higher in the R group. All of the R group newborns and 75% of the RC group newborns were found to be neurologically healthy at the 24-hour examination. RESULTS: There were no statistically significant differences between the groups regarding pain score, sensory block level, duration of epidural analgesia or Apgar score. The latency time, duration of labor analgesia and motor block were R group < RC group. The half-hour and two-hour neurological and adaptive capacity scores were higher in the R group. All of the R group newborns and 75% of the RC group newborns were found to be neurologically healthy at the 24-hour examination. CONCLUSION: Both low-dose ropivacaine and a lower dose plus clonidine relieved maternal pain during obstetric labor. Newborns of mothers who received only ropivacaine showed better neurological and adaptive capacity scores.

Preoperative warming combined with intraoperative skin-surface warming does not avoid hypothermia caused by spinal anesthesia in patients with midazolam premedication.

CONTEXT AND OBJECTIVE: Inadvertent perioperative hypothermia is common during spinal anesthesia and after midazolam administration. The aim of this study was to evaluate the effects of intraoperative skin-surface warming with and without 45 minutes of preoperative warming in preventing intraoperative and postoperative hypothermia caused by spinal anesthesia in patients with midazolam premedication. DESIGN AND SETTING: Prospective and randomized study at Hospital das Clínicas, Universidade Estadual Paulista, Botucatu. METHODS: Thirty patients presenting American Society of Anesthesiologists (ASA) physical status I and II who were scheduled for elective lower abdominal surgery were utilized. The patients received midazolam premedication (7.5 mg by intramuscular injection) and standard spinal anesthesia. Ten patients (Gcontrol) received preoperative and intraoperative passive thermal insulation. Ten patients (Gpre+intra) underwent preoperative and intraoperative active warming. Ten patients (Gintra) were only warmed intraoperatively. RESULTS: After 45 min of preoperative warming, the patients in Gpre+intra had significantly higher core temperatures than did the patients in the unwarmed groups (Gcontrol and Gintra) before the anesthesia (p < 0.05) but not at the beginning of surgery (p > 0.05). The patients who were warmed intraoperatively had significantly higher core temperatures than did the patients in Gcontrol at the end of surgery (p < 0.05). All the patients were hypothermic at admission to the recovery room (T CORE < 36 degrees C). CONCLUSIONS: Forty-five minutes of preoperative warming combined with intraoperative skin-surface warming does not avoid but minimizes hypothermia caused by spinal anesthesia in patients with midazolam premedication.

[Effect of propofol in combination with ephedrine upon the onset time of cisatracurium]. / Efeito do propofol associado à efedrina no tempo de latência do cisatracúrio.

OBJECTIVE: The onset time of neuromuscular blocking drugs is partially determined by circulatory factors, including muscle blood flow and cardiac output. The aim of the present paper was to: 1) compare the haemodynamic effects of adding different doses of ephedrine to an induction dose of propofol and remifentanil. 2) onset time of cisatracurium. METHODS: Sixty patients were randomly allocated into three groups: G1 - 1% propofol; G2 - 1% propofol + 0.5 mg.ml-1 ephedrine and G3 - 1% propofol + 1.0 mg.ml-1 ephedrine. All patients received continuous infusion of remifentanil (0.5 mg.kg-1.min-1). The rate of propofol infusion was 180 ml.h-1 until loss of consciousness and a loading dose of cisatracurium (0.15 mg.kg-1) was then given. After induction of anesthesia, the ulnar nerve was stimulated supramaximally every 10s, and the evoked twitch response of the adductor pollicis was recorded by accelerometry. RESULTS: There was no statistical difference between groups with respect to age, weight, dose of propofol administered and onset time of cisatracurium. Heart rate, SpO2, systolic, diastolic and mean blood pressures were compared at 1 and 3 min post-induction. There were statistical differences in HR, SAP, DAP and MAP, without significant adverse clinical effects. CONCLUSIONS: There were no clinically important decreases in the hemodynamic parameters evaluated in the groups receiving ephedrine or not, and the onset time of cisatracurium was the same for all groups.

The effects of intrathecal administration of betamethasone over the dogs' spinal cord and meninges.

PURPOSE: To determinate the potential clinical and histological changes due the injection of betamethasone, when administered into the canine intrathecal space. METHODS: Twenty one animals were included in a random and blind manner in the study. After general anesthesia, intrathecal puncture was performed and 1 ml of the random solution was injected. The G1 dogs received 0.9% saline solution, the G2 dogs received 1.75 mg betamethasone and the G3 dogs received 3.5 mg of betamethasone. The animals were clinically evaluated for 21 days and then sacrificed. The lumbar and sacral portions of the spinal cord were removed for light microscopy histological analyses. RESULTS: No clinical changes were observed in any of the animals included in this study. No histological changes were observed in G1 animals. Inflammatory infiltration was observed in two dogs, one in G2, another in G3. Hemorrhage and necrosis were also seen in the G2 dog which inflammatory infiltration was detected. In other two dogs, one from G2 and another from G3, there was discreet fibrosis and thickness of the arachnoid layer which was focal in one and diffuse in the other. CONCLUSION: Intrathecal administration of betamethasone caused histological changes in the spinal cord and meninges in some of the dogs involved in this study.

Ultrasound as a safe and reliable guidance for subarachnoid puncture in rabbits.

PURPOSE:: To evaluate a model for studying the toxicity in nervous tissue and meninges using ultrasound to guide needle insertion into the subarachnoid space of rabbits, with the objective of avoiding injuries triggered by the puncture and by intraneural injection of solutions. METHODS:: Forty-five adult female rabbits were divided into 3 groups (G): G1 underwent subarachnoid puncture, G2 underwent subarachnoid injection of saline solution and G3 underwent subarachnoid injection of 0.5% hyperbaric bupivacaine. A needle was inserted into the S1-S2 subarachnoid space guided by ultrasound. The sensitivity and motility of the animals were evaluated for 3 days, after which the animals were sacrificed for removal of lumbar and sacral portions of the spinal cord for histological examination by light microscopy and immunohistochemistry. RESULTS:: All animals had motor function and pain sensitivity on the evaluation period. No animal had complication during or after the procedures. CONCLUSION:: Ultrasound is a useful and safe method for the correct identification of the subarachnoid space of rabbits.

Influence of S(+)-ketamine analgesia in renal intraoperative ischemia: histological study in rats.

PURPOSE: To study in rats the effect of S(+) ketamine on the renal histology after intraoperative hemorrhage. METHODS: Twenty male Wistar rats, anesthetized with sodium pentobarbital, were randomly divided in 2 groups: G1 - control (n=l0) and G2 - S(+)-ketamine (n=10), both submitted to arterial hemorrhage of 30% of volemia in 3 moments (10% each 10 min) 60 min after anesthesia. G2 received S(+)-ketamine, 15 mg. kg-1, i.m., 5 min after anesthesia and 55 min before the 1st hemorrhage moment (Ml). Medium arterial pressure (MAP), rectal temperature (T) and heart rate were monitored. The animals were sacrificed in M4, 30 min after the 3rd hemorrhage moment (M3) and the kidneys and blood collected from hemorrhage were utilized for histological study and hematocrit (Ht) determination. RESULTS: There were significant reduction of MAP, T, and Ht. The histological study verified G1 = G2 for tubular dilation, congestion, and necrosis. The total score addition were significantly different and G2 > G 1. CONCLUSION: Hemorrhage and hypotension determined changes in kidney histology. The rise in catecholamine blood concentration probably was the cause of S(+)-ketamine-induced higher score of histological changes.

Decompressive Hemicraniectomy in a South American Population--Morbidity and Outcomes Analysis.

BACKGROUND: Malignant cerebral artery strokes have a poor prognosis, with nearly 80% of mortality in some series despite intensive care. After a large randomized trial, decompressive hemicraniectomy has been performed more often in stroke patients. Here, we describe patients in a tertiary teaching hospital in Brazil, emphasizing the impact of age on outcomes. METHODS: A retrospective cohort of patients, with malignant strokes which received a decompressive hemicraniectomy, from paper and electronic medical records, from January 2010 to December 2013 was divided into two groups according to age. RESULTS: The final analysis included 60 patients. The overall mortality was higher among patients older than 60 yrs (67% vs. 41%; p = 0.039), whose group also had a worse outcome (76% with mRS 5 or 6) at 90 days (OR 3.91 CI95% 1.30-11.74), whereas only 24% had mRS of 0-4 (p = 0.015). All patients who presented with sepsis died (p = 0.003). The incidence of pulmonary infection was very high in the elderly group (76%) with significant intergroup differences (p = 0.027, OR 8.32 CI95% 0.70-98.48). CONCLUSIONS: Older patients present more commonly with infections, more disabilities and a higher mortality, highlighting very poor results in elderly population. These results should be proved with a South American trial, and if confirmed, it can impact on future decisions regarding decompressive craniectomy for acute ischemic stroke in our region.

Myocardial contractility impairment with racemic bupivacaine, non-racemic bupivacaine and ropivacaine. A comparative study.

PURPOSE: To study racemic bupivacaine, non-racemic bupivacaine and ropivacaine on myocardial contractility. METHODS: Isolated Wistar papillary muscles were submitted to 50 and 100 mM racemic bupivacaine (B50 and B100), non-racemic bupivacaine (NR50 and NR100) and ropivacaine (R50 and R100) intoxication. Isometric contraction data were obtained in basal condition (0.2 Hz), after increasing the frequency of stimulation to 1.0 Hz and after 5, 10 and 15 min of local anesthetic intoxication. Data were analyzed as relative changes of variation. RESULTS: Developed tension was higher with R100 than B100 at D1 (4.3 ± 41.1 vs -57.9 ± 48.1). Resting tension was altered with B50 (-10.6 ± 23.8 vs -4.7 ± 5.0) and R50 (-14.0 ± 20.5 vs -0.5 ± 7.1) between D1 and D3. Maximum rate of tension development was lower with B100 (-56.6 ± 38.0) than R50 (-6.3 ± 37.9) and R100 (-1.9 ± 37.2) in D1. B50, B100 and NR100 modified the maximum rate of tension decline from D1 through D2. Time to peak tension was changed with NR50 between D1 and D2. CONCLUSIONS: Racemic bupivacaine depressed myocardial contractile force more than non-racemic bupivacaine and ropivacaine. Non-racemic and racemic bupivacaine caused myocardial relaxation impairment more than ropivacaine.

Serum cystatin C is a sensitive early marker for changes in the glomerular filtration rate in patients undergoing laparoscopic surgery.

OBJECTIVE: Pneumoperitoneum during laparoscopy results in transient oliguria and decreased glomerular filtration and renal blood flow. The presence of oliguria and elevated serum creatinine is suggestive of acute renal injury. Serum cystatin C has been described as a new marker for the detection of this type of injury. In this study, our aim was to compare the glomerular filtration rate estimated using cystatin C levels with the rate estimated using serum creatinine in patients with normal renal function who were undergoing laparoscopic surgery. METHODS: In total, 41 patients undergoing laparoscopic cholecystectomy or hiatoplasty were recruited for the study. Blood samples were collected at three time intervals: first, before intubation (T1); second, 30 minutes after the establishment of pneumoperitoneum (T2); and third, 30 minutes after deflation of the pneumoperitoneum (T3). These blood samples were then analyzed for serum cystatin C, creatinine, and vasopressin. The Larsson formula was used to calculate the glomerular filtration rate based on the serum cystatin C levels, and the Cockcroft-Gault formula was used to calculate the glomerular filtration rate according to the serum creatinine levels. RESULTS: Serum cystatin C levels increased during the study (T1 = T2T3; p<0.05). The calculated eGlomerular filtration rate-Larsson decreased, whereas the eGlomerular filtration rate-Cockcroft-Gault increased. There was no correlation between cystatin C and serum creatinine. Additionally, Pearson's analysis showed a better correlation between serum cystatin C and the eGlomerular filtration rate than between serum creatinine and the eGlomerular filtration rate. CONCLUSION: This study demonstrates that serum cystatin C is a more sensitive indicator of changes in the glomerular filtration rate than serum creatinine is in patients with normal renal function who are undergoing laparoscopic procedures.

Effects of catecholamines on volemic replacement with saline solution and the impact on heart rate variability in rabbits subjected to hemorrhage. A study by spectral analysis.

PURPOSE: To verify the effects of different catecholamines on volemic expansion and on the autonomic nervous system in rabbits that were subjected to hemorrhage. METHODS: Twenty four rabbits subjected to hemorrhage (with a 25% loss of blood volume) and were randomly divided into four experimental groups: 1) HEMO Group underwent replacement with their own blood in an equal volume; 2) SS Group underwent replacement with saline solution (SS) in a volume that corresponded to three times the removed blood volume; 3) ISP Group underwent replacement with SS and isoprenaline; 4) FNL Group underwent replacement with SS and phenylephrine. Spectral Analysis of the heart rate and heart rate variability were performed from the recorded data. Hematocrit was measured throughout the experiment. RESULTS: Replacement with SS and an α- or ß-agonist did not produce differences in the intravascular retention compared to replacement with SS alone. An analysis of HRV showed that the FNL group maintained the LF/HF ratio better than ISP and SS. CONCLUSIONS: No difference in vascular retention when α- or ß- agonists were added to SS during post-hemorrhagic recovery. The animals in the FNL group maintained the integrity of the autonomic response within normal physiological standards during hemorrhagic stress.

Ultrasound as a safe and reliable guidance for subarachnoid puncture in rabbits

Abstract Purpose: To evaluate a model for studying the toxicity in nervous tissue and meninges using ultrasound to guide needle insertion into the subarachnoid space of rabbits, with the objective of avoiding injuries triggered by the puncture and by intraneural injection of solutions. Methods: Forty-five adult female rabbits were divided into 3 groups (G): G1 underwent subarachnoid puncture, G2 underwent subarachnoid injection of saline solution and G3 underwent subarachnoid injection of 0.5% hyperbaric bupivacaine. A needle was inserted into the S1-S2 subarachnoid space guided by ultrasound. The sensitivity and motility of the animals were evaluated for 3 days, after which the animals were sacrificed for removal of lumbar and sacral portions of the spinal cord for histological examination by light microscopy and immunohistochemistry. Results: All animals had motor function and pain sensitivity on the evaluation period. No animal had complication during or after the procedures. Conclusion: Ultrasound is a useful and safe method for the correct identification of the subarachnoid space of rabbits.

Reevaluation of the airways of obese patients undergone bariatric surgery after reduction in body mass index.

BACKGROUND AND OBJECTIVES: Difficulty intubating is a cause of mortality in anesthesiology and it can be related to obesity. The diagnosis of difficult intubation contributes for successful airways management. However, parameters that predict difficult airways are not well established. Mallampati classification, the interincisor gap, neck circumference, thyromental distance, and the presence of obstructive sleep apnea, are parameters that can indicate difficult intubation. Surgical treatment of obesity provides reduction in body mass index (BMI) with stabilization after about 2 years. The objective of the present study was to reevaluate the parameters described above and compare them with pre-surgical values. METHODS: The BMI, Mallampati classification, neck circumference, interincisor gap, thyromental distance, and the degree of obstructive sleep apnea in polysomnography were evaluated in 51 patients of both genders in the preoperative period. Two years after the surgery and reduction of the BMI to < 35 kg.m(-2), predictor factors of difficult airways were reevaluated by another anesthesiologist who knew the patients' BMI before surgery. Nine patients were excluded. The new reevaluation was performed, and for those who did not have another polysomnography the somnolence scale of Epiworth was applied. RESULTS: Forty-two patients were reevaluated. They showed a reduction in BMI and neck circumference, and an increase in both interincisor gap and thyromental distance. Only one patient showed a reduction in Mallampati scale, and only 4 patients performed polysomnography. CONCLUSIONS: Reduction of the BMI allows for an increased interincisor gap, thyromental distance, and reduction in neck circumference. Mallampati classification remains the same.

Continuous bilateral posterior lumbar plexus block with a disposable infusion pump: case report.

BACKGROUND AND OBJECTIVES: The number of bilateral total hip arthroplasties (THA) has been increasing every year. Postoperative analgesia by continuous perineural infusion of local anesthetic has been shown favorable results when compared to systemic analgesia. The use of elastomeric pumps has increased patient satisfaction when compared to electronic models. The objective of this report was to describe a case of continuous bilateral posterior lumbar plexus block with an elastomeric infusion pump in a patient submitted to bilateral hip arthroplasty. CASE REPORT: This is a 46 year-old female patient weighing 65 kg, 162 cm, with rheumatoid arthritis and hypertension, physical status ASA II, scheduled for bilateral THA in a single stage. She had been on corticosteroids for 13 years. Hemoglobin=10.1 g.dL⁻¹, hematocrit=32.7%. Routine monitoring. Spinal anesthesia with 15 mg of 0.5% isobaric bupivacaine. General anesthesia with propofol (PFS) and remifentanil, and intubation without neuromuscular blockers. Right THA and, at the end, lumbar plexus block with a stimulator and a set of 150 mm needle and injection of 20 mL of 0.2% bupivacaine and introduction of a catheter. Left THA and, at the end, the same procedure. Anesthetic dispersion and contrast were investigated. Elastomeric pump was installed with 0.1% bupivacaine (400 mL) at a rate of 14 mL.h⁻¹. The patient was transferred to the Intensive Care Unit (ICU). After 24 hour, a new pump was installed with the same solution. She did not receive any boluses for 50 hours. After removal of the catheter, pain was controlled with oral ketoprofen and dypirone. CONCLUSIONS: Continuous peripheral blockade with infusion of 0.1% bupivacaine with elastomeric pumps is a safe and effective procedure in adults.