[The anesthesiologist facing terminality: a survey-based observational study]

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.

The anesthesiologist facing terminality: a survey-based observational study

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 the Brazilian 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.

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.

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.

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.

Clinical and Histological Effects of the Intrathecal Administration of a Single Dose of Dexmedetomidine in Rabbits

Background: There is experimental evidence that dexmedetomidine has neuroprotective effects. So, it could be expected that its intrathecal or epidural administration presents no harm. However, whether dexmedetomidine is neurotoxic to the spinal cord remains to be fully elucidated. Objective: To evaluate the effect of preservative-free dexmedetomidine administered as a subarachnoid single injection on the spinal cord and meninges of rabbits. Study Design: Research article. Setting: Experimental research laboratory. Methods: Twenty young adult female rabbits, each weighing between 3200 and 4900 g, and having a spine length between 36 and 40 cm, were divided by lot into 2 groups (G): 0.9% saline in G1 and preservative-free dexmedetomidine in G2 (dose of 10 μg). After intravenous anesthesia with ketamine and xylazine, the subarachnoid space was punctured at S1-S2 under ultrasound guidance, and a random 5 µl.cm-1 of spinal length (0.2 mL) of solution (saline or dexmedetomidine) was injected. The animals remained in captivity for 21 days under medical observation and were sacrificed by decapitation. The lumbosacral spinal cord portion was removed for immunohistochemistry to assess the glial fibrillary acidic protein (GFAP), and histology was assessed using hematoxylin and eosin (HE) stain. Results: None of the animals had impaired motor function or decreased nociception during the period of clinical observation. None of the animals from the control group showed signs of injuries to meninges. In the dexmedetomidine group, however, 9 animals presented with signs of meningeal injury. The main histological changes observed were areas with meningeal thickening and lymphoplasmocitary infiltration in the pia-mater and arachnoid. Further histological examination also revealed adherence areas among the pia and arachnoid. There was no signal of injury in neural tissue in any animal of both groups. Limitations: Evaluation of the possible analgesic effects of the intrathecal dexmedetomidine was not performed. Conclusion: On the basis of the present results, dexmedetomidine administered in the subarachnoid space in a single dose of 10 µg is capable of producing histological changes over the meninges of rabbits. Key Words: Anesthesia, spinal; dexmedetomine; injections, spinal; spinal cord; rabbits

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.

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 β-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 β- 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.

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 = T2<T3; p<0.05), whereas serum creatinine levels decreased (T1 = T2>T3; 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.

[Hemodynamic changes during pneumoperitoneum in volume and pressure controlled ventilated dogs.]

BACKGROUND AND OBJECTIVES

There are no studies associating ventilation-induced effects and hemodynamic changes during pneumoperitoneum. This study aimed at evaluating hemodynamic changes determined by pneumoperitoneum in dogs under volume and pressure controlled ventilation.

METHODS

The study involved 16 dogs anesthetized with sodium thiopental and fentanyl, divided in group 1: volume controlled; and group 2: pressure controlled; submitted to 10 and 15 mmHg pneumoperitoneum. The following parameters were evaluated: heart rate, mean blood pressure, right atrium pressure, pulmonary capillary wedge pressure, cardiac index, systemic vascular resistance index and plasma vasopressin. Data were collected in four moments: M1 - before pneumoperitoneum, M2 - 30 minutes after 10 mmHg pneumoperitoneum; M3 - 30 minutes after 15 mmHg pneumoperitoneum; M4 - 30 minutes after pneumoperitoneum deflation.

RESULTS

Results have shown increased cardiac index, right atrium pressure and pulmonary capillary wedge pressure in M2 and M3 for all groups. Vasopressin was not changed during procedure and systemic vascular resistance index has not increased, providing mean blood pressure stability for both groups.

CONCLUSIONS

Ventilation modes have not determined hemodynamic differences between studied groups. Anesthetic technique and intra-abdominal pressure have determined mean blood pressure stability, probably due to the absence of systemic vascular resistance index increase.

[Effects of pneumoperitoneum on renal hemodynamics and function of dogs under volume and pressure-controlled ventilation.]

BACKGROUND AND OBJECTIVES

There are no studies associating ventilatory mode effects on renal repercussions during pneumoperitoneum. This study aimed at evaluating pneumoperitoneum-induced renal hemodynamics and function changes in dogs under volume and pressure controlled ventilation.

METHODS

This study involved 16 dogs anesthetized with sodium thiopental and fentanyl, which were divided in two groups: Group 1: volume controlled; and Group 2: pressure controlled, both submitted to 10 and 15 mmHg pneumoperitoneum. The following parameters were evaluated: renal blood flow, renal vascular resistance, sodium para-aminohippurate clearance, plasma sodium, plasma potassium, plasma osmolality, creatinine clearance, filtration fraction, urinary volume, urinary clearance, osmolar clearance, free water clearance, sodium clearance, sodium urinary excretion, sodium fractional excretion, potassium clearance, potassium urinary excretion and potassium fractional excretion. Data were collected in 4 moments: M1 before pneumoperitoneum, M2, 30 minutes after 10 mmHg pneumoperitoneum, M3, 30 minutes after 15 mmHg pneumoperitoneum, M4, 30 minutes after pneumoperitoneum deflation.

RESULTS

Sodium para-aminohippurate and creatinine clearance remained constant for both groups throughout the experiment. Plasma sodium and potassium were not changed. There has been potassium clearance and fractional excretion decrease as from M2 in both groups.

CONCLUSIONS

Ventilatory modes have not promoted renal hemodynamic differences between groups. Pneumoperitoneum, by compressing renal parenchyma, may have determined changes in potassium reabsorption and/or secretion.

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.

Continuous spinal anesthesia with high dose of local anesthetics

BACKGROUND AND OBJECTIVES

Better control of the level, intensity, and duration of spinal analgesia represents the greatest advantages of continuous spinal anesthesia. With the advent of intermediate catheters (over-the-needle catheter) and its low incidence of headaches and neurological symptoms, the technique has been gaining credibility. The objective of this paper is to report the possible safety of the new catheter with a large dose of hyperbaric 0.5% bupivacaine with 1.6% glucose associated with hyperbaric 2% lidocaine with 1.6% glucose.

CASE REPORT

Male patient, 78 years old, 85 kg, 168 cm, physical status ASA III, with hypertension, coronary artery disease, and chronic renal failure. The patient was candidate for surgery for huge bilateral inguinal and umbilical hernias, being submitted to preoperative pneumoperitoneum for one week to stretch abdominal cavity. After venoclysis with an 18G catheter, he was monitored with cardioscope, non-invasive blood pressure, and pulse oximetry; he was sedated with 1 mg of midazolam and 100 μg of fentanyl intravenously, and placed in left lateral decubitus. He underwent continuous spinal anesthesia by a median puncture in L₃-L₄ with a set with a 27G cut-bevel needle and 22G catheter. The total dose of anesthetic used was 25mg of 0.5% bupivacaine (hyperbaric, with 1.6% glucose), 160 mg of 2% lidocaine (hyperbaric, with 1.6% glucose), and morphine (100 μg). The patient was followed-up until the 30th postoperative day without neurological complaints.

CONCLUSIONS

Recently, the poor distribution of the local anesthetic through the microcatheter was attributed as the cause of cauda equina syndrome. This case report showed that, with the administration of high doses of hyperbaric anesthetics through the new catheter, poor distribution or risk of cauda equina syndrome were not observed.

Onset time and duration of rocuronium, atracurium and mivacurium in pediatric patients

BACKGROUND AND OBJECTIVES

Neuromuscular blockers (NMB) are widely used in pediatric anesthesia, but there is no ideal NMB. This study aimed at evaluating onset and recovery time, hemodynamic changes and tracheal intubation conditions of rocuronium, atracurium and mivacurium in pediatric patients.

METHODS

Participated in this study 67 children aged 30 months to 12 years, physical status ASA I and II, who were allocated into three groups: G1 = 0.9 mg kg(-1) rocuronium (n = 22); G2 = 0.5 mg kg(-1) atracurium (n = 22); G3 = 0.15 mg kg(-1) mivacurium (n = 23). Anesthesia was induced with 50 microg kg(-1) alfentanil, 3 mg kg(-1) propofol, sevoflurane and N2O/O2. Neuromuscular block was monitored by acceleromyography on the ulnar nerve pathway. The following parameters were evaluated: onset time (OT), clinical duration (T25) relaxation time (T75) and recovery time (T(25-75)). Heart rate (HR) and mean blood pressure (MBP) were recorded in 6 moments, as well as tracheal intubation conditions.

RESULTS

Median OT was: G1 = 0.6 min, G2 = 1.3 min, G3 = 1.9 min. Median T25 was: G1 = 38 min, G2 = 41.5, G3 = 8.8 min. Median T75 was: G1 = 57.7 min; G2 = 54.6 min, G3 = 13.6 min. Median T(25-75) was: G1 = 19.7 min, G2 = 13.1 min and G3 = 4.8 min. Tracheal intubation conditions were excellent for most children in all groups. There were no significant MBP and HR clinical changes.

CONCLUSIONS

Rocuronium (0.9 mg kg(-1)) had the fastest onset time and mivacurium (0.15 mg kg(-1)) the shortest recovery time in pediatric patients anesthetized with sevoflurane. Rocuronium, mivacurium and atracurium had also not determined significant hemodynamic changes and allowed for excellent tracheal intubation conditions.

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.

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.

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.

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.

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 significant1y 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.

[Effects of increasing spinal hyperbaric lidocaine concentrations on spinal cord and meninges: experimental study in dogs]

BACKGROUND AND OBJECTIVES

Lidocaine concentration potentially able to determine nervous tissue injury is still not well established. This study aimed at investigating the effect of increasing spinal lidocaine concentrations in single injection through Quincke needle.

METHODS

After the Animal Experiment Ethical Committee approval, 40 adult animals were anesthetized with fentanyl and etomidate and submitted to spinal puncture with 22G 21/2 Quincke needle for the introduction of 1 mL of 7.5% glucose solution in 10 seconds - Group 1; 5% lidocaine in 7.5% glucose solution - Group 2; 7.5% lidocaine in 7.5% glucose solution - Group 3; 10% lidocaine in 7.5% glucose solution - Group 4. After intravenous anesthesia recovery and in the presence of spinal block, the following parameters were observed: presence of motor block, anal sphincter tone (normal or relaxed) and sensory block level in different cervical, thoracic, lumbar and sacral dermatomes. Animals remained in captivity for 72 hours. Anal sphincter tone, hind paws mobility, painful fore and hind paws and sacral, lumbar and thoracic dermatomes sensitivity were evaluated. Were euthanized by electrocution under anesthesia and spinal cord and meningeal lumbar and sacral portions were removed for histological exam under optic microscopy.

RESULTS

No Group 1 and 2 animal presented clinical or histological injuries. Three Group 3 animals presented hind paws motor changes and anal sphincter relaxation with foci of posterior necrosis (two dogs) and fascial necrosis in all spinal cord surface (one dog). In a different animal of this group in which foci of necrosis were observed in less than 5% histological field, no clinical changes were found. Seven Group 4 animals presented clinical changes (paralysis or decreased muscle strength in hind paws, anal sphincter relaxation) or histological changes (spinal cord surface band necrosis or nervous tissue necrosis foci).

CONCLUSIONS

In this study, spinal lidocaine in concentrations above 7.5% in single injection through Quincke needle has determined histological changes on spinal cord, but not on meninges.

Perioperative cardiac arrest: a study of 53 718 anaesthetics over 9 yr from a Brazilian teaching hospital

BACKGROUND

Little information exists regarding factors influencing perioperative cardiac arrests and their outcome. This survey evaluated the incidence, causes and outcome of perioperative cardiac arrests in a Brazilian tertiary general teaching hospital between April 1996 and March 2005.

METHODS

The incidence of cardiac arrest during anaesthesia was prospectively identified from an anaesthesia database. There were 53,718 anaesthetics during the study period. Data collected included patient characteristics, surgical procedures (elective, urgent or emergency), ASA physical status classification, anaesthesia provider information, type of surgery, surgical areas and outcome. All cardiac arrests were retrospectively reviewed and grouped by cause of arrest and death into one of four groups: totally anaesthesia related, partially anaesthesia related, totally surgery related or totally patient disease or condition related.

RESULTS

One hundred and eighty-six cardiac arrests (34.6:10,000) and 118 deaths (21.97:10,000) were found. Major risk factors for cardiac arrest were neonates, children under 1 yr and the elderly (P<0.05), male patients with ASA III or poorer physical status (P<0.05), in emergency surgery (P<0.05) and under general anaesthesia (P<0.05). Patient disease/condition was the major cause of cardiac arrest or death (P<0.05). There were 18 anaesthesia-related cardiac arrests (3.35:10,000) -- 10 totally attributed (1.86:10,000) and 8 partially related to anaesthesia (1.49:10,000). There were 6 anaesthesia-related deaths (1.12:10,000) -- 3 totally attributable and 3 partially related to anaesthesia (0.56:10,000 in both cases). The main causes of anaesthesia-related cardiac arrest were respiratory events (55.5%) and medication-related events (44.5%).

CONCLUSIONS

Perioperative cardiac arrests were relatively higher in neonates, infants, the elderly and in males with severe underlying disease and under emergency surgery. All anaesthesia-related cardiac arrests were related to airway management and medication administration which is important for prevention strategies.

Hemodynamic and ventilatory effects of volume or pressure controlled ventilation in dogs submitted to pneumoperitoneum. Comparative study

BACKGROUND AND OBJECTIVES

Pressure controlled ventilation (PCV) is available in anesthesia machines, but there are no studies on its use during CO2 pneumoperitoneum (CPP). This study aimed at evaluating pressure-controlled ventilation and hemodynamic and ventilatory changes during CPP, as compared to conventional volume controlled ventilation (VCV).

METHODS

This study involved 16 dogs anesthetized with thiopental, fentanyl and pancuronium, which were randomly assigned to two groups: VC - volume controlled ventilation (n=8) and PC - pressure controlled ventilation (n=8). Hemodynamic and ventilatory parameters were monitored and recorded in 4 moments: M1 (before CPP), M2 (30 minutes after CPP = 10 mmHg), M3 (30 minutes after CPP=15 mmHg) and M4 (30 minutes after deflation).

RESULTS

With CPP, there has been significant increase in tidal volume in PC group; there has been increase in airway pressures (peak and plateau), decrease in compliance with increase in CPP pressure, increase in heart rate, maintenance of mean blood pressure with higher values in the VC group in all stages; there was also increase in right atrium pressure with significant decrease after deflation, decrease in arterial pH with minor variations in PC group, greater arterial pCO2 stability in PC group, and no significant changes in arterial pO2.

CONCLUSIONS

There were some differences in hemodynamic and ventilatory data between both ventilation control modes (VC and PC). It is possible to use pressure controlled ventilation during CPP, but the anesthesiologist must monitor and take a close look at alveolar ventilation, adjusting inspiratory pressure to ensure proper CO2 elimination and oxygenation.

Efficacy of N-butylscopolamine and sodium dipirone associated to ketoprofen for postoperative pain relief of patients submitted to two different laparoscopic sterilization techniques

BACKGROUND AND OBJECTIVES

Laparoscopic sterilization (LS) is one of the most painful procedures and pain severity varies with the selected technique, being more severe when tubes are occluded with rings. Patients submitted to LS refer PO colic pain and N-butylscopolamine and sodium dipirone, for their anti-spasmodic and analgesic properties, associated to ketoprofen with anti-inflammatory properties, may be the option for pain prevention and relief. This study aimed at evaluating the efficacy of N-butylscopolamine and sodium dipirone associated to ketoprofen to prevent PO pain in patients submitted to LS by two different techniques - diathermy and tubal ring.

METHODS

Participated in this study 50 patients, physical status ASA I and II, aged 23 to 47 years. Patients were randomly distributed in two groups: G1 - tubal ring; G2 - diathermy. All patients received intravenous N-butylscopolamine (20 mg) and sodium dipirone (2500 mg) and ketoprofen (100 mg) immediately before anesthetic induction. Pain was evaluated by verbal numeric scale varying from 0 to 10, being 0 no pain and 10 the worst possible pain, every 10 minutes in the first PACU hour and 1, 2, 3 and 4 hours after PACU discharge. Pain above 3 was treated with intravenous tramadol (100 mg). Pain was evaluated without knowing the group to which the patient belonged. Student's t, Mann-Whitney and Friedman tests were used for statistical analysis.

RESULTS

Both groups were similar in age, weight, height and length of surgery and anesthesia. G1 patients had higher pain scores as compared to G2, in all studied moments. Statistically significant values were: 80% of G1 and 16% of G2 patients needed tramadol at some point of the study.

CONCLUSIONS

N-butylscopolamine and sodium dipirone associated to ketoprofen are a postoperative analgesic alternative when sterilization is performed through diathermy technique.

Renal and cardiovascular effects of dopamine and 7.5% sodium chloride infusion: experimental study in dogs with water restriction

BACKGROUND AND OBJECTIVES

Dopamine infusion for renal protection is controversial. This study aimed at observing the effects of dopamine, hypertonic solution and the association of both in dogs with water restriction, emulating preoperative fast.

METHODS

The following renal function parameters were studied in 32 dogs anesthetized with sodium pentobarbital and fentanyl: effective renal plasma flow (sodium para-aminohippurate clearance), glomerular filtration rate (creatinine clearance), sodium, potassium and osmolar clearance, sodium and potassium fractional excretion and renal vascular resistance. Cardiovascular parameters were: mean blood pressure, heart rate, inferior vena cava pressure, cardiac index, hematocrit and peripheral vascular resistance index. Animals were randomly distributed in four experimental groups: Group 1 - G1 (n = 8) - control group; Group 2 - G2 (n = 8) - dopamine infusion (2 microg kg(-1) min(-1)); Group 3 - G3 (n = 8) - 7.5% sodium chloride (2 ml kg(-1)) and Group 4 - G4 (n = 8) - association of dopamine (2 microg kg(-1) min(-1)) and 7.5% sodium chloride (2 ml kg(-1)). Groups underwent four experimental stages lasting 30 minutes each, and involving moments M1, M2, M3 and M4.

RESULTS

Dopamine group (G2) had mean blood pressure, renal vascular resistance and potassium excretion decrease. Hypertonic sodium chloride group (G3) had cardiac index, urinary volume, sodium and potassium clearance, sodium and potassium urinary excretion and sodium fractional excretion increase. Group receiving the association of hypertonic solution and dopamine (G4) had heart rate, cardiac index, effective renal plasma flow and sodium urinary excretion increase; there has also been systemic vascular resistance and plasma potassium index decrease.

CONCLUSIONS

Our conclusion was that hypertonic sodium chloride solution was able to improve hemodynamic conditions and, as a consequence, renal function of dogs under 12-hour water restriction. The same was not true for 2 microg kg(-1) min(-1) dopamine which, in a similar situation, has not increased diuresis and sodium excretion.

[Patient with upper airway infectious disease. When to induce anesthesia?]

BACKGROUND AND OBJECTIVES

Anesthesia in children with upper airway infection (UAI) is a major challenge for Anesthesiologists. This paper aimed at discussing why and when to induce anesthesia in UAI children.

CONTENTS

Preoperative clinical history, factors contributing to peri and postoperative complications and the type of surgery and anesthetic technique favoring such complications are highlighted.

CONCLUSIONS

The understanding of post-UAI respiratory tract changes, of the importance of accurately evaluating the severity of symptoms, of factors contributing to complications and of the best anesthetic technique will allow for the choice of patients at the lowest risk to develop perioperative complications.

[Effects of spinal administration of large volumes of 2% lidocaine and 1% ropivacaine on spinal cord and meninges: experimental study in dogs]

BACKGROUND AND OBJECTIVES

Spinal injection of large local anesthetic volumes after accidental dural puncture is an epidural anesthesia complication. This study aimed at investigating potential clinical and histological changes triggered by large volumes of 2% lidocaine or 1% ropivacaine in a simulated accidental spinal injection in dogs.

METHODS

Twenty one dogs were randomly allocated into three experimental groups, which received spinal injections of: G1 - 0.9% sodium chloride, G2 - 2% lidocaine, G3 - 1% ropivacaine. Spinal puncture was performed in L6-L7 interspace. Anesthetic volume was 1 ml per 10 cm-distance between the occipital protuberance and the lumbosacral space (5 - 6.6 ml). After 72 hours of clinical observation animals were sacrificed and their spinal cords were removed for histological examination under light microscopy.

RESULTS

No G1 animal presented clinical or histological changes in the spinal cord. There were two cases of nervous tissue necrosis in G2, however clinical changes were only observed in one of these dogs and in two other dogs which had no histological changes. There has been focal necrosis in the spinal cord nervous tissue of one G3 animal. All G3 animals remained clinically normal.

CONCLUSIONS

Large volumes of 2% lidocaine have determined more intensive clinical and histological changes as compared to 1% ropivacaine.

[Efficacy of propofol and propofol plus dexamethasone in controlling postoperative nausea and vomiting of gynecologic laparoscopy.]

BACKGROUND AND OBJECTIVES

Gynecological laparoscopy is a procedure associated to a high incidence of postoperative nausea and vomiting (PONV). This study aimed at comparing the efficacy of propofol or propofol plus dexamethasone in preventing PONV in patients submitted to gynecological laparoscopy.

METHODS

Forty female patients, physical status ASA I and II, aged 18 to 46 years, with no previous gastric complaint, undergoing diagnostic or surgical laparoscopy were randomly distri- buted in 2 groups: Group 1 - patients were given 2 ml IV saline solution, while Group 2 was given intravenous dexamethasone (8 mg), before anesthetic induction. All patients were premedicated with oral midazolam (7.5 mg) and induced with sufentanil (0.5 microg.kg-1) and propofol targed controlled infusion (BIS 60), with N2O/O2 (F I O2=0.4) for maintenance. Neuromuscular block was obtained with atracurium (0.5 mg.kg-1). Postoperative analgesia consisted of ketoprofen (100 mg) and butyl-eschopolamine plus dipirone. Patients were evaluated in the PACU and in the ward after 1, 2, 3 and 12 hours after PACU discharge.

RESULTS

Both groups were identical regarding demographics data as well as surgery and anesthesia duration. One Group 1 patient referred nausea in postanesthetic care unit and in the ward, and 3 patients referred vomiting in the ward. In Group 2, no patient referred nausea and vomiting, but the difference was not statistically significant.

CONCLUSIONS

Propofol or propofol plus dexamethasone were efficient in preventing PONV in patients submitted to gynecological laparoscopy.

[Spinal anesthesia-induced neurological complications.]

BACKGROUND AND OBJECTIVES

Although rare, spinal anesthesia-induced neurological complications may determine serious sequelae. This study aimed at presenting these complications in order to elucidate triggering factors and help in the diagnosis of such injuries.

CONTENTS

The following complications are presented: needle and catheter-induced nerve injury, post dural puncture headache, anterior spinal artery syndrome, spinal hematoma, septic meningitis, aseptic meningitis, adhesive arachnoiditis, cauda equina syndrome, and transient neurological symptoms.

CONCLUSIONS

The understanding of triggering factors of spinal anesthesia-induced neurological complications may prevent injuries and help early diagnosis and treatment, therefore changing patients prognosis.