Anesthesia and surgery in very precarious conditions. Clinical cases

We performed herniorrhaphy on 21 children (4 of them infants) and 3 adults, in very precarious conditions, in a hospital in a economically depressed area of the Democratic Republic of Congo. Anesthesia technique used in adults was subarachnoid and intravenous and intramuscular ketamine in children. Ketamine is an irreplaceable anesthetic in many parts of the world without resources, where the minimum safety means are not available. Knowing the simple anesthetic techniques, but with less risk, can also be useful in resourceful places, in unexpected situations. Greater solidarity is needed, both from anesthesia societies and from anesthesiologists, to alleviate the great deficiencies in well-trained professionals and means in places without resources.

Review of difficult airway management in thoracic surgery

The management of difficult airway (DA) in thoracic surgery is more difficult due to the need for lung separation or isolation and frequent presence of associated upper and lower airway problems. We performed an article review analysing 818 papers published with clinical evidence indexed in Pubmed that allowed us to develop an algorithm. The best airway management in predicted DA is tracheal intubation and independent bronchial blockers guided by fibroscopy maintaining spontaneous ventilation. For unpredicted DA, the use of videolaryngoscopes is recommended initially, and adequate neuromuscular relaxation (rocuronium/sugammadex), among other maneuvers. In both cases, double lumen tubes should be reserved for when lung separation is absolutely indicated. Finally, extubation should be a time of maximum care and be performed according to the safety measures of the Difficult Arway Society.

[Problem/case-based learning compared to lectures for acquiring knowledge of air embolism in continuing medical education]

OBJECTIVE

The efficacy of continuing medical education in anesthesiology has been examined very little. This study compared the efficacy of a lecture on air embolism to that of a class that used a problem/case-based learning approach.

MATERIAL AND METHODS

Prospective, randomized study enrolling 52 experienced anesthesiologists participating in a professional development course. Twenty-six anesthesiologists attended a lecture on air embolism in anesthesia and 25 attended a problem-based class. The objectives were the same for both groups and had been defined previously. The participants' knowledge was evaluated before and after the instruction with tests based on 2 cases dealing with the same knowledge areas: risk factors and symptoms, diagnosis, monitoring, and treatment.

RESULTS

No significant between-group differences were found for any of the knowledge areas before or after the classes. After instruction, participants who listened to the lecture improved their scores for knowledge of monitoring (P = .03) and treatment (P = .001). Participants in the problem-based learning group also improved their scores for knowledge of treatment (P = .003).

CONCLUSIONS

No between-group differences in participants' knowledge outcomes were detected; improvements were minimal. The study design allowed the knowledge acquired to be evaluated objectively.

[Survey of anesthetic techniques used in Catalonia: results of the analysis of 23,136 anesthesias (2003 ANESCAT study)]

OBJECTIVE

To examine anesthesia practice in Catalonia in 2003 and to describe the specific characteristics and distribution of the anesthesia techniques used and the patient profiles.

PATIENTS AND METHODS

We used the data from the ANESCAT epidemiological study that gathered information in questionnaire form on all anesthesias performed in Catalonia on 14 randomly selected days representative of practice in 2003.

RESULTS

All 131 hospitals authorized to perform anesthesia participated in the study. We collected 23136 questionnaires, from which we extrapolated to estimate 603189 anesthesias for the year and a rate of 9.0 anesthesias per 100 inhabitants per year. Fifty-eight percent of the patients were women and the mean age was 52 years. The physical status of the patients was as follows: ASA 1 or 2, 73.3%; ASA 3, 213%; ASA 4 or 5, 5.4%. The mean duration of anesthesia was 60 minutes. The most common form of anesthesia was a regional block (41.4%) and spinal block was the one performed most often. General anesthesia was used in 33.5% of the cases, combined anesthesia in 3.5%, and sedation in 21.6%. In descending order, orthopedics/trauma, ophthalmology, general surgery, obstetrics, cataract surgery, vaginal delivery, inguinal hernia repair, and colonoscopy were the procedures for which anesthesia was most commonly administered.

CONCLUSIONS

Almost 1 in 10 persons in Catalonia are given anesthesia each year and most of the procedures involve locoregional anesthesia or sedation. These data provide a picture of the current situation of anesthesiology and make it possible to forecast future anesthesia requirements.

[Two cases of early postoperative massive pulmonary thromboembolism after gastric bypass surgery]

Pulmonary thromboembolism in the early postoperative period is rare. We present 2 cases of massive embolism that occurred soon after gastric bypass surgery. The first patient was a 32-year-old man, a smoker with a body mass index (BMI) of 52 kg/m2, obstructive sleep apnea-hypopnea syndrome and venous insufficiency in the lower extremities. Fatal cardiorespiratory arrest occurred 22 hours after surgery. Autopsy confirmed massive pulmonary thromboembolism. The second patient was a 48-year-old woman with a BMI of 40 kg/m2 who had undergone abdominal hysterectomy 2 months earlier. She survived cardiorespiratory arrest occurring 11 hours after surgery. There were no sequelae. The diagnosis of pulmonary thromboembolism was confirmed by transesophageal echocardiography. These patients undoubtedly had asymptomatic deep vein thrombosis before the operations. Prevention of pulmonary embolism is essential in high risk patients. The prophylactic measures usually applied are administration of low molecular weight heparin to prevent thrombosis, early ambulation, and the use of elastic compression stockings or intermittent pneumatic compression.

[Anesthesia with sevoflurane for tonsillectomy in a boy with Duchenne muscular dystrophy]

A 6-year-old boy with Duchenne muscular dystrophy (DMD) and foreseen difficult tracheal intubation underwent tonsillectomy under general inhaled anesthesia with sevoflurane. No neuromuscular blockers were administered and no perioperative complications emerged. In spite of advances in genetic diagnosis there continue to be patients with DMD because of spontaneous mutation of the dystrophin gene. Late detection leaves them vulnerable to administration of drugs like succinylcholine that can trigger fatal reactions involving hyperpotassemia, rhabdomyolysis, and malignant hyperthermia. Total intravenous anesthesia seems the best way to provide general anesthesia for a patient with DMD. Inhaled anesthesia is an alternative. Although halogenated agents can lead to rhabdomyolysis and malignant hyperthermia, the frequency seems low if we bear in mind that the use of sevoflurane is widespread in pediatrics. In this case sevoflurane induction facilitated safe tracheal intubation.

[Bradycardia-tachycardia syndrome during spinal anesthesia]

A 78-year-old man developed bradycardia with decreased level of consciousness followed by sinus arrest during femoropopliteal bypass surgery under subarachnoid anesthesia. Early in the recovery period, a similar clinical picture developed, with bradycardia but no change in level of consciousness. Sinus node automaticity or sinoatrial conduction abnormalities were suspected, and a 24-hour Holter electrocardiogram revealed bradycardia-tachycardia syndrome. The patient was prescribed amiodarone and anticoagulant therapy with acenocoumarol; no further episodes occurred during hospitalization. Bradycardia-tachycardia syndrome is a sinus node disorder that manifests intermittently. It can become apparent during or shortly after surgery, leading to problems of differential diagnosis.

[Postoperative patient-controlled analgesia is more effective with epidural methadone than with intravenous methadone in thoracic surgery]

OBJECTIVE

To compare the efficacy and side effects of epidural and intravenous methadone for postoperative patient-controlled analgesia (PCA) after thoracic surgery.

PATIENTS AND METHODS

A randomized, single-blind trial enrolling 30 patients distributed in 2 groups to receive intravenous methadone (ivPCA group) or epidural methadone (epPCA group). Patients in both groups were administered a loading dose of 0.05 mg.kg-1 followed by infusion of 0.5 mg.h-1. The patients could self-dose 0.5 mg with a lock-out interval of 10 minutes and a maximum of 4 doses per hour. Patient characteristics, type and duration of surgery and fentanyl dose were recorded. Pain was assessed on a visual analog scale (VAS). Level of sedation, respiratory rate and occurrence of nausea, vomiting and pruritus were also recorded over the first 24 hours.

RESULTS

The 2 groups were comparable. Pain was greater in the ivPCA group than in the epPCA group in the second hour (VAS 3.93 +/- 1.9 and 2.4 +/- 1.65, respectively; P < .05) and the third hour (VAS 3.57 +/- 1.65 and 1.5 +/- 1.16, respectively; P < .05). The total dose of methadone administered was 25.34 +/- 5.65 mg in the ivPCA group and 18.82 +/- 3.52 mg in the epPCA group (P < .002). There were no significant differences in side effects.

CONCLUSIONS

The results suggest that epidural methadone has an intrinsic spinal effect regardless of whether or not there is extra-spinal action arising from syste mic absorption. Epidural methadone provides a more adequate analgesic effect in less time and at a lower dose. Both approaches provide good postoperative analgesia with few side effects.

[Obstetric analgesia and anesthesia with remifentanyl in a patient with von Willebrand disease]

A 30-year-old woman with von Willebrand's disease was admitted in labor. As epidural analgesia was ruled out due to risk of spinal hematoma, a pump for patient-controlled analgesia (PCA) was provided with boluses of remifentanil and set for intravenous infusion of 24 micrograms with a lockout time of 5 minutes. The patient reported analgesia to be satisfactory. Later, because of abnormal fetal positioning, an emergency cesarean was performed with the patient under general anesthesia with remifentanil, with propofol and succinylcholine for induction. A healthy girl was born free of respiratory depression. Von Willebrand's disease is a hemorrhagic disorder of autosomal dominant inheritance due to a quantitative or functional factor VIII deficit. Various subtypes and degrees of severity of abnormal bleeding have been described. It is the most common genetic hemostatic disorder affecting obstetric procedures, and although epidural analgesia has been used with strict hematologic monitoring, that technique carries a risk of hematoma. PCA is useful in patients for whom regional techniques are contraindicated. With adequate fetal and maternal monitoring, remifentanil in PCA is safe and more effective than other opiates for labor pain.

Anaesthetic and postoperative analgesic effects of spinal clonidine as an additive to prilocaine in the transurethral resection of urinary bladder tumours

BACKGROUND AND OBJECTIVE

The alpha 2-adrenoceptor agonist clonidine has potent central antinociceptive properties. The study was designed to investigate the effects of the combined subarachnoid administration of clonidine and prilocaine on spinal block and postoperative analgesia for the transurethral resection of tumours in the urinary bladder.

METHODS

The controlled, prospective, double-blind study enrolled 40 patients scheduled for elective transurethral resection of bladder tumours under spinal anaesthesia with prilocaine. Patients were randomly assigned to receive an intrathecal injection of prilocaine 75 mg alone (control group) or in combination with clonidine 75 micrograms. We assessed haemodynamic changes (non-invasive arterial pressure, heart rate), pulse oximetry, the upper level of block, the onset and duration of sensory and motor block, postoperative analgesia and any adverse effects.

RESULTS

There were no statistically significant differences in demographic data, heart rate, onset time or the levels of sensory or motor block. Analgesia lasted significantly longer in the clonidine group (498.4 +/- 226.9 versus 187.2 +/- 103.1 min; P < 0.05). The duration of motor block was longer in the clonidine group (165.5 +/- 30.6 min) than in the control group (139.7 +/- 40.4 min; P < 0.05) and the duration of sensory block was also longer in the clonidine group (157.3 +/- 24.5 min) than in the control group (137.2 +/- 31.2 min; P < 0.05). Fewer patients in the recovery room needed metamizol (dipyrone) in the clonidine group (5%) than in the control group (50%). Arterial pressure decreased significantly in the clonidine group 75-135 min after the block.

CONCLUSIONS

The addition of clonidine 75 micrograms to prilocaine 75 mg for subarachnoid anaesthesia increased the duration of sensory and motor block and reduced the need for additional postoperative analgesics by providing excellent analgesia for about 8 h during recovery from transurethral resection of bladder tumours.

[Morbidity and mortality related to anesthesia and surgery in 60 patients treated with bariatric surgery]

OBJECTIVE

To identify the factors predicting morbidity and mortality in patients undergoing bariatric surgery for morbid obesity in our hospital.

METHOD

Sixty bariatric surgery patients whose body mass indexes (BMI) exceeded 35 kg.m-2 were studied retrospectively. We examined the incidence of associated disease, the perioperative period, type of surgery, anesthetic technique, postoperative analgesia and the incidence of major complications.

RESULTS

Fifty-one women and 9 men (mean age 43.33 +/- 10.25 years, mean BMI 46.41 +/- 6.04 kg/m-2) were studied. The incidences of high blood pressure (55%) and obstructive sleep apnea syndrome (40%) were high. Nine patients (15%) were physical status (ASA) I, 18 (30%) were ASA II, 27 (45%) were ASA III and 6 (10%) were ASA IV. Major complications developed in 3 cases (5%) in the first 24 h and in 8 (13.33%) in the first 7 days. The mortality rate was 0% among ASA I and II patients, 3.7% (1 death) among ASA III patients, and 33.33% (2 deaths) among ASA IV patients. All who died were men. The only factor that predicted morbidity in the first week after surgery was BMI. Both morbidity in the first 24 h and mortality were associated with greater underlying disease in our patients undergoing bariatric surgery.

CONCLUSION

Major complications of bariatric surgery occurred in 18.3% of our patients and mortality was 5%. Physical status was a prognostic factor for both early (24 h) postoperative morbidity and mortality in our morbidly obese patients, whereas BMI was related to morbidity during the first week after surgery.

Cardiovascular Response and Anesthetic Recovery in Electroconvulsive Therapy with Propofol or Thiopental

Propofol provokes a slight hypotensive effect that could mitigate the cardiovascular response to electroconvulsive therapy (ECT). In this study we compared the effects of propofol and thiopental for ECT anesthesia in seven women (22-67 years of age). Anesthesia was induced with either thiopental or propofol, and with atropine and suxamethonium for each treatment. The first anesthesia was assigned to thiopental or propofol at random; the next anesthesia was induced with the other drug, and alternated thereafter. Systolic blood pressure, diastolic blood pressure (DBP), and heart rate (HR) were recorded before anesthesia, after anesthetic induction, and 1 and 5 min after ECT. ECT-induced increases in DBP and HR were less marked with propofol than with thiopental. Seizure durations were decreased with propofol compared with thiopental.

[Placement of a double-lumen tube using a 6 mm diameter fibro-bronchoscope and a Cook exchange catheter in a patient with unforeseen tracheal intubation difficulty]

The trachea of a 74-year-old man undergoing left pneumonectomy could not be intubated in two attempts after induction of anesthesia with midazolam, fentanyl, propofol and rocuronium. Difficult intubation had not been foreseen, but inspection through the laryngoscope revealed Cormack and Lehane grade IV conditions. Because a small-caliber fiberoptic bronchoscope was unavailable for intubation with a double-lumen endobronchial tube, we inserted a No. 9 orotracheal tube with a 6 mm bronchoscope as far as the left main bronchus. Intubation was aided by a universal adaptor for fiberoptics with a face mask and a Williams cannula. We were then able to ventilate the patient manually with 100% oxygen during bronchoscopy. As selective ventilation was required during surgery, a No. 11 Cook-type airway exchange catheter was inserted into the left main bronchus, the tracheal tube was removed, and was used to guide a No. 39F left double-lumen endobronchial tube through the bronchus. Insertion was uncomplicated and selective ventilation was satisfactory. The technique described is a new application for the Cook exchange catheter that allows selective bronchial in difficult cases when a small-caliber fiberoptic bronchoscope is unavailable.

[Spanish doctoral dissertations on anesthesiology and the scientific publications of their authors]

OBJECTIVES

To determine whether obtaining a doctorate is a factor that promotes the research careers of the authors. To analyze the dissemination of Spanish doctoral theses in anesthesiology by looking at the publications they generate.

MATERIAL AND METHODS

The TESEO data base was searched for theses on anesthesiology written between 1976 and June 2001. The Medline database was then searched for publications related to each author's thesis. The search identified papers related to each thesis as well as those in which the thesis director was a coauthor.

RESULTS

Two hundred twenty-eight theses (9.12 theses/year) were found. Twenty-four authors were not anesthesiologists. The universities of Barcelona (28), Valencia (24), Navarra (23), Autónoma de Barcelona (21), Complutense de Madrid (18) and Cádiz (18) accounted for most of the theses read. The doctoral degree recipients also co-authored 1,833 publications, as the first authors of 649 articles, of which 216 (33.3%) were published before the corresponding thesis was read. Only 127 articles were related to theses. Ninety-seven authors (42.5%) published no article as first author and 22 (9.6%) accomplished no publication as co-author. The thesis director was listed in 154 of the 228 theses in the TESEO database. In this subgroup, 39 doctoral thesis authors published 58 related articles, with the director included among the co-authors in 41 of them.

CONCLUSION

Spain produces few doctoral theses on anesthesiology. Most writers of doctoral theses do not publish the results in journals with international readerships. These findings call into question the efficacy of the doctoral thesis as a factor that promotes research.

[Remifentanil or propofol for sedation in subarachnoid anesthesia. Effects on ventilation, hemodynamic stability and bispectral index]

OBJECTIVES

To compare depth of sedation, hemodynamic and respiratory effects, and bispectral index (BIS) in surgical patients under subarachnoid anesthesia with intravenous perfusion of 1 mg/kg/h of propofol or 3 microgram/kg/h of remifentanil or placebo.

PATIENTS AND METHOD

Fifty-one elective surgery patients were randomly assigned to one of 3 groups: propofol (n = 17), remifentanil (n = 17) or placebo (n = 17). We monitored ECG, blood pressure (BP), respiratory frequency (RF), oxygen saturation by pulse oximetry (SpO2), nasal end tidal carbon dioxide pressure (PETCO2), BIS and sedation on the Observer's Assessment of Alertness/Sedation scale (OAA/S). Five minutes after starting subarachnoid anesthesia, we initiated the assigned intravenous perfusion. Measurement of hemodynamic variables, BIS, PETCO2, RF and OAA/S score occurred at baseline, every 5 minutes during surgery and after withdrawal of sedation at intervals until recovery of baseline values.

RESULTS

Patient data and SpO2 were similar in the 3 groups. PETCO2, FR and OAA/S did not change significantly from baseline in the placebo group but were significantly different in the other groups. BIS was significantly lower in the propofol group than in either the remifentanil or the control group. Times to recovery were similar in the two sedation groups. Slight complications were observed in 35.3% patients in the propofol group, 53.3% in the remifentanil group and 7.7% in the placebo group; complications were mainly nausea, pruritus and hypoventilation in the remifentanil group and venous pain in the propofol group.

CONCLUSIONS

The sedation regimens used were safe and adequate. Propofol is associated with fewer complications than remifentanil.

[Model to predict staffing for anesthesiology and post-anesthesia intensive care units and pain clinics]

Human resources account for a large part of the budgets of anesthesia and post-anesthesia intensive care units and pain clinics (A-PICU-PC). Adequate staffing is a key factor in providing for both effective care and professional staff development. Changes in professional responsibilities have rendered obsolete the concept of one anesthesiologist per operating room. Duties must be analyzed objectively to facilitate understanding between hospital administrators and A-PICU-PC chiefs of service when assigning human resources. The Catalan Society of Anesthesiology, Post-anesthesia Intensive Care and Pain Therapy has developed a model for estimating requirements for A-PICU-PC staffing based on three factors: 1) Definition of staff positions that must be filled and criteria for assigning human resources; 2) Estimation of non-care-related time required by the department for training, teaching, research and internal management, and 3) Estimation of staff required to cover absences from work for vacations, personal leave or illness. The model revealed that the ratio of number of staff positions to number of persons employed by an A-PICU-PC is approximately 1.3. Differences in the nature of services managed by an A-PICU-PC or the type of hospital might change the ratio slightly. The model can be applied universally, independently of differences that might exist among departments. Widespread application would allow adoption of a common language to be used by health care managers and A-PICU-PC departments when discussing a basis for consensus about our specialty.

[Expected versus real impact factors of publications from Spanish departments of anesthesiology (1991-1996)]

OBJECTIVE

To identify publications by Spanish anesthesiologists in journals indexed by Journal Citation Report from 1991 through 1996; to count the number of citations received and compare the results with the impact factor (IF) of the journals in which they were published.

MATERIAL AND METHODS

Articles for which the first author was a member of a Spanish anesthesiology department were searched for in MEDLINE, Science Citation Index and EMBASE. Only publications for which the IF was known were included for analysis. We then counted the number of citations each article received over the two years following publication, recording the source journal in which the citation appeared and country of origin of each citing author. We then calculated the real IF (RIF) of each article, the RIF of all the Spanish articles, and the mean RIF. Also calculated for each article was the expected IF (EIF), based on the IF of the source journal, the overall EIF and the mean EIF.

RESULTS

One hundred seventy-two articles were published; 49 of them were letters to the editors. Specialist anesthesiology journals published 72.7%. A total of 186 citations were received. American authors cited the articles more often than did other Spanish authors. Thirty-seven citations (19.9%) were self-citations. Ninety-two articles (53.5%) were never cited. With letters to the editor excluded, the RIF was 85.48 and the global EIF was 213.28; the mean EIF was 1.734 and the RIF was 0.695. Therefore, the rate of citation of the Spanish authors in the period studied was only 40% of the citation rate of the entire population of authors from all countries. The authors of the published articles worked mainly in hospitals in Barcelona, Madrid, La Coruña, Valencia, Cantabria and Murcia. Hospital Germans Trias i Pujol (Badalona, Barcelona) had the largest number of publications and the highest EIF (39.41). Hospital del Mar (Barcelona) had the highest mean RIF and the highest global RIF.A gradual increase in the annual productivity of Spanish scientists can be discerned in a progressive increase in the number of publications as well as their EIF and RIF.

CONCLUSIONS

Research by Spanish anesthesiologists is concentrated in only a few hospitals. Although the number of publications is increasing, their international repercussion has still not reached the desired level.

[Pregnancy and partum in the woman with a spinal cord lesion in chronic phase]

A 34-year-old pregnant paraplegic woman with a T12 medullary lesion in chronic phase underwent cesarean delivery in the thirty-seventh week due to pelvic-cephalic disproportion. After failure of epidural anesthesia related to technical difficulties, general anesthesia was provided. A hypertensive crisis developed during surgery but was resolved within minutes after administration of hydralazine. No further complications arose. Pregnancy in a patient with medullary lesion in chronic phase is considered high risk, requiring special care due to extraordinary changes in pathophysiology caused by the lesion in addition to changes directly related to gestation. The main complications that arise are decreased respiratory volume and arterial pressure, increased incidence of thromboembolic events, anemia, urinary tract infections, premature birth, unusual progression of delivery and autonomic hyperreflexia, which is the most serious. When a hypertensive peak develops in such patients, the anesthesiologist must first rule out autonomic hyperreflexia, which has an incidence of 85% in lesions over T7 and has also been described in patients with lower lesions.

[Impact factor of the Revista Española de Anestesiología y Reanimación for 1997 and 1998]

OBJECTIVES

Revista Española de Anestesiología y Reanimación (REDAR) is not listed in the Journal Citation Reports (JCR) of the Institute for Scientific Information (ISI) and therefore REDAR's impact factor (IF) is unknown. This study aimed to calculate REDAR's IF and immediacy index for the years 1997 and 1998 as well as the IF that the journal would have had if it were considered an ISI source journal. The study also aimed to analyze self-citations and how they would affect the IF if REDAR were considered a source journal.

MATERIAL AND METHODS

We calculated the IF and immediacy indexes using ISI methodology, by manually counting the references to REDAR articles published in 1997 and 1998 and singling out self-citations.

RESULTS

The IF was 0.014 for 1997 and 0.054 for 1998. If REDAR had been considered a source journal in 1997 the IFs would have been 0.437 for 1997 and 0.419 for 1998. The immediacy indexes were 0.37 for 1997 and 0.30 for 1998. The mean number of references per article for the two-year period under study was 19.04 with differences depending mainly on type of article. The highest numbers of self-citations and the highest proportions of the same were found in letters to the editor and authors' replies. The 30 author-plus-journal self citations accounted for 9.3% of all self-citations (n = 322).

CONCLUSION

The IF of REDAR is far lower than those of other European journals. If REDAR were accepted as a source journal, it would benefit from its self-citations. Improving REDAR's if would result in greater international recognition of our scientific level.

[Isobaric 2% lidocaine in continuous subarachnoid anesthesia using microcatheters]

The objective in the study of the clinical effect of isobaric 2% lidocaine for continuous spinal anesthesia with a microcatheter technique. Nine consecutive patients undergoing lower abdominal surgery under spinal anesthesia were enrolled. We inserted 27 G catheters through 22 G Sprotte (Intralong) needles to administer 20 mg of isobaric 2% lidocaine followed by successive doses of 10 mg until the required level of anesthesia was reached. Repeated injections of 10 mg were given during surgery whenever the level of anesthesia fell as much as one metamere, possibly permitting pain to appear. We recorded hemodynamic variables, level of anesthesia and motor block, as well as complications during and after surgery. The technique was used with nine patients, for whom the mean presurgical dose was 32.3 +/- 9.2 mg and the mean total dose was 51.3 +/- 25.3 mg. However, the protocol for administering the local anesthetic was suspended in three patients due to difficulty in maintaining the achieved level of anesthesia, as repeated injections were required, with consequent patient discomfort. In these patients relatively high levels of blockade were required and surgery lasted longer than one hour. The protocol followed with isobaric 2% lidocaine was not effective for continuous spinal anesthesia with microcatheters because of difficulty of maintaining level of anesthesia.

[Comparative study between 5% prilocaine and 2% mepivacaine by the subarachnoid route in transurethral resections]

OBJECTIVE

To compare the duration of spinal block with 5% prilocaine and 2% mepivacaine in short procedures for transurethral resection and to assess possible complications in the immediate postoperative period.

MATERIAL AND METHODS

Fifty-seven patients scheduled for transurethral resection of the prostate or a vesical tumor. Patients were ASA I-III, over 55 years of age and randomly assigned to two groups to receive 5% prilocaine (1 mg/kg, n = 27) or 2% mepivacaine (0.8 mg/kg, n = 30). We collected data on anesthetic technique, levels of extension of motor and sensory blockades, duration of blockades and complications within the first 24 hours after surgery.

RESULTS

Demographic data, ASA classification and duration of surgery were similar in both groups. We found statistically significant differences (p < 0.05) in duration of sensory blockade (120.92 +/- 36.21 min with prilocaine and 145.83 +/- 35.81 min with mepivacaine) and in motor blockade (106.29 +/- 38.16 min with prilocaine and 133.16 +/- 42.21 min with mepivacaine). Five cases of hypotension and 4 of bradycardia occurred in each group and one patient in the mepivacaine group suffered slight postoperative cephalea.

CONCLUSIONS

Both local anesthetics offer good surgical conditions with hemodynamic stability and few complications. The duration of sensory and motor blockade is shorter with prilocaine than with mepivacaine, making prilocaine more appropriate for short interventions.

[Study of presurgical anxiety in urologic, gynecologic, and ophthalmologic surgery as a function of the administration or non-administration of anxiolytic premedication]

OBJECTIVE

Anxiety commonly appears before surgery, triggering a set of events that can be described as a general stress response. We measured changes in preoperative stress in relation to premedication or not with diazepam in patients undergoing urologic, gynecologic and ophthalmologic surgery.

PATIENTS AND METHOD

We enrolled 87 patients undergoing elective surgery in urology (n = 30), gynecology (n = 30) and ophthalmology (n = 27). Randomly, the patients were premedicated with diazepam, placebo or nothing. During the preoperative visit the patient was administered a test to determine the level of anxiety and blood pressure, heart rate and potassium plasma concentration (K+) the night before surgery and moments before entering the operating theater.

RESULTS

No significant differences in anxiety between patients undergoing different types of surgery were detected in the operating theater; however, at that time, anxiety was found to be significantly less among patients premedicated with diazepam than among those given placebo. Preoperative anxiety was significantly less in ophthalmology patients and in those premedicated with diazepam. Both systolic and diastolic blood pressure increased significantly among urologic and ophthalmologic surgery patients and in those who were not premedicated with diazepam regardless of type of surgery. Heart rate did not change significantly. Potassemia decreased significantly in all patients.

CONCLUSION

The discrepancy between the psychological and somatic response to the stress conditions studied may be the result of the calming effect of the preoperative visit by the anesthesiologist and to premedication with a tranquilizer. However, neither the preoperative visit nor premedication seem to completely block the stress response.

[Abdominal compartmental syndrome in non-injured patients]

Abdominal compartment syndrome (ACS) is characterized by increased intraabdominal pressure and a set of secondary pathophysiological changes in the abdominal. ACS has reappeared in the literature recently in relation to the surgical concept to damage control, applied particularity in contexts of severe abdominal injury polytraumatized patients. We report two cases of ACS that appeared after scheduled abdominal surgery: one after repair of a large eventration and the other in the context of septic shock due to fecaloid peritonitis. Both patients died of multisystem organ failure in spite of surgical decompression. We wish to emphasize that ACS can appear in contexts other than surgery for damage control, and we stress the need to measure intravesical pressure as a reflection of intraabdominal pressure, particularly in certain high risk patients in the postoperative recovery ward. Finally, we review the pathophysiology of ACS and its management, which is based on early treatment to prevent multisystem organ failure with an associated high risk of death.

[Effectiveness of isobaric 0.5% bupivacaine and 5% lidocaine in continuous subarachnoid anesthesia with microcatheters]

OBJECTIVES

To study the clinical effect of two isobaric local anesthetics infused through microcatheters for continuous subarachnoid anesthesia.

MATERIAL AND METHODS

Patients undergoing surgery under continuous subarachnoid anesthesia were enrolled prospectively over 12 months. Twenty-seven-gage catheters were inserted through 22 G Sprotte (Intralong) needles. The two isobaric anesthetics (0.5% bupivacaine and 5% lidocaine) were studied in two successive six-month periods. One milliliter of local anesthetic was administered, followed by incremental doses of 0.5 ml until the required anesthetic level was reached. Hemodynamic variables were recorded, as were levels of anesthetic and motor blockade and complications developing during the surgical and postoperative periods.

RESULTS

Thirty-one patients were anesthetized with isobaric 0.5% bupivacaine and 40 with isobaric 5% lidocaine. A high blockade was observed in three patients in the bupivacaine group and in 15 in the bupivacaine group (p < 0.05). The highest anesthetic level reached was T4. Hypotension occurred in one patient in the bupivacaine group and in 10 in the lidocaine group (p < 0.05). Blockade was difficult to increase to the appropriate level in 11 lidocaine patients and in one bupivacaine patient, whereas blockade of distal roots was difficult in 13 bupivacaine patients and in 7 lidocaine patients (p < 0.005). The total doses infused were 11.0 +/- 3.0 mg of 0.5% bupivacaine and 95.6 +/- 24.6 mg of 5% lidocaine.

CONCLUSIONS

Isobaric 0.5% bupivacaine provides a more predictable anesthetic blockade with greater hemodynamic stability and a lower rate of difficulty in raising the level of blockade than does 5% lidocaine when administered through microcatheters for continuous subarachnoid anesthesia.

[Comparative study of 3 techniques for total intravenous anesthesia: midazolam-ketamine, propofol-ketamine, and propofol-fentanyl]

OBJECTIVE

To compare the characteristics of induction, maintenance and awakening for three techniques of combined total intravenous anesthesia (TIVA): propofol-ketamine, midazolam-ketamine and propofol-fentanyl.

PATIENTS AND METHODS

Sixty patients were randomly assigned to three TIVA groups. Group 1 (n = 20) received midazolam, ketamine and vecuronium. Group 2 (n = 20) received propofol, ketamine and vecuronium. Group 3 (n = 20) received propofol, fentanyl and vecuronium. The variables compared were hemodynamic changes during induction and maintenance and upon awakening; time until awakening; and the incidence of postanesthetic complications. We also assessed whether propofol was better than midazolam at preventing the psychomimetic effects of ketamine.

RESULTS

The demographic characteristics of the three groups were similar. Hemodynamic variables were most stable in group 2. Perfusion of midazolam-ketamine was accompanied by a significantly higher number of hypertensive peaks. Time to awakening was significantly shorter in Group I (11.8 +/- 5 min) than in group 2 (20.2 +/- 12.5 min); in group 2 time to awakening was 16.6 +/- 5.6 min. Eight patients in group 1, 5 in group 2 and 1 in group 3 reported having bad dreams, the difference between groups 1 and 3 reaching statistical significance. No patient experienced hallucinations and all reported satisfaction with the anesthetic technique used.

CONCLUSIONS

TIVA with ketamine and propofol is comparable to the most commonly used combination of propofol and fentanyl and may be an appropriate choice when hemodynamic stability is of great importance; withdrawal 15 min before ending surgery prevents prolonged awakening. Perfusion of midazolam-ketamine is not recommendable for scheduled surgery because it induces too many hypertensive peaks. Although neither midazolam nor propofol completely prevents the psychomimetic effects of ketamine, such effects are not so severe that patients reject the anesthetic technique used.

[Nasal ketamine compared with nasal midazolam in premedication in pediatrics]

OBJECTIVE

To compare the efficacy and side effects of midazolam and ketamine administered nasally for pediatric premedication.

PATIENTS AND METHODS

In this double blind trial 60 children scheduled for elective surgery were randomly assigned to two groups to receive 0.25 mg.kg or 5 mg.kg nasal ketamine. We measured level of acceptance of medication, sedation, hemodynamic variables, reaction to separation from parents, side effects and time until recovery from anesthesia.

RESULTS

The two groups were homogeneous. Acceptance of medication was good or adequate in all patients. The level of sedation was significant in both groups 10 min after premedication. Systolic arterial pressure was higher in the ketamine group 20 min after administration of the drug and upon arrival in the operating theater. Reaction to separation from parents was good in all groups. Secretions were higher in the ketamine group and hallucinations were experienced by three patients in the ketamine group and by two in the midazolam group. We found no difference in time until spontaneous eye opening after surgery. No complications were observed.

CONCLUSIONS

The nasal route is adequately accepted by children. Both drugs are effective by this route and sedation is rapid. Time until postanesthetic recovery is similar with both drugs. The doses used have wide safety margins.

Postoperative respiratory function in children after abdominal surgery. A comparison of epidural and intramuscular morphine analgesia

Thirty children undergoing urological and abdominal surgery were entered into a randomised trial comparing the effects of epidural and intramuscular morphine on postoperative respiratory function. The forced vital capacity and the forced expired volume in 1 s were measured before and 6 h after surgery and on each of the following seven days. Significant decreases (p < 0.01) in forced vital capacity and forced expired volume in 1 s were seen after surgery. After the first postoperative day, a gradual recovery in pulmonary function was observed but the measured parameters had not returned to their pre-operative control values by the end of the study. There were no statistically significant differences between the two groups during the study with respect to forced vital capacity and forced expired volume in 1 s. The quality of analgesia was better in the epidural morphine group than in the intramuscular morphine group. The incomplete recovery of pulmonary function suggests that pain is not the only cause of postoperative respiratory changes in these patients.

[Comparison of lidocaine and urapidil for prevention of hemodynamic response to tracheal intubation in patients in general good health]

OBJECTIVE

To compare the efficacy of endovenous administration of 0.5 mg/kg-1 of urapidil to 1 mg/kg-1 of lidocaine for attenuating hemodynamic response to laryngoscopy and tracheal intubation.

PATIENTS AND METHODS

Study of 40 ASA I and II patients with normal blood pressure undergoing elective surgery under general anesthesia with orotracheal intubation. The patients were randomly assigned to two groups to receive either 0.5 mg/kg-1 of urapidil or 1 mg/kg-1 five minutes before anesthetic induction. Anesthesia was provided with 0.04 mg/kg-1 of midazolam, 2 micrograms/kg-1 of fentanyl, 2 mg/kg-1 of propofol, 0.1 mg/kg-1 of vecuronium before proceeding to orotracheal intubation, after electromyographic determination of neuromuscular response with T1 less than 5%, and laryngoscopy. Heart rate, systolic, diastolic and mean pressures, and the product of heart rate and mean arterial pressure (HR x MAP) were recorded at the following times: baseline (before administering either lidocaine or urapidil), after induction, after laryngoscopy and intubation, and 3 minutes and 5 minutes after intubation.

RESULTS

ASA classification, age, sex and weight were similar in the two groups. Heart rate immediately after intubation, and after 3 and 5 minutes was significantly lower in the lidocaine group. Likewise HR x MAP immediately after intubation and 3 minutes later was significantly lower in the patients who received lidocaine.

CONCLUSIONS

In healthy ASA I and II patients with normal blood pressure, a dose of 1 mg/kg-1 of lidocaine provided better protection against the hemodynamic response to laryngoscopy and tracheal intubation than does 0.5 mg/kg-1 of urapidil.

[Compromized postadenoidectomy respiration in a child with obstructive sleep apnea syndrome]

A two-year-old boy with a history of slow growth, snoring during sleep and adenoid hypertrophy underwent adenoidectomy and transtympanic drainage under general anesthesia. Immediately after extubation, severe inspiratory stridor and shallow labored breathing began and persisted over a period of two hours, in spite of corticoid administration and oxygen therapy. The signs receded partially when the patient was seated and with a mandibular traction maneuver. As symptoms persisted, foreign body obstruction was ruled out by examination of the cavum and upper airway under general anesthesia and with orotracheal intubation. The patient was transferred to the pediatric intensive care unit, where he remained intubated for 18 hours. After extubation, stridor and shallow labored breathing reappeared but gradually receded as the residual effects of sedation disappeared. The parents mentioned symptoms suggestive of obstructive sleep apnea syndrome (OSAS) occurring since the boy was 6 months old and that had worsened in recent months. OSAS in children is characterized by intermittent obstruction of the upper airway during sleep, causing snoring and periods of apnea/hypopnea that lead to hypoxemia and hypercapnia. The most frequent cause is hypertrophy of the adenoid and tonsils, and the treatment of choice is adenotonsillectomy, although the risk of postoperative respiratory distress in such children is high. It is important to rule out OSAS in children who are candidates for adenotonsillectomy so that such patients are not scheduled for ambulatory surgery, but rather given adequate postoperative monitoring and treatment.

[Gas embolism secondary to intraoperative use of hydrogen peroxide]

Hydrogen peroxide solution (H2O2) is used to irrigate and clean wounds. When applied to tissue hydrogen peroxide decomposes rapidly as a result of the action of catalases, releasing oxygen in the process. High pressure irrigation of the washing of closed cavities can cause serious complications. We report a case of gas embolism arising from the use of hydrogen peroxide during surgery for hydatidosis of the liver. A 64-year-old woman underwent surgery for removal of a hydatid cyst of the liver. When pressurized injection of 10 ml of 3% hydrogen peroxide was applied to the cystic cavity, cardiac arrhythmias were observed, a long with decreased PetCO2, hypotension and a "water mill" heart murmur. Gas embolism was suspected and treatment was instated immediately. Clinical course was good and without complications. We wish to warn against the potential dangers of using peroxide during surgery and of the importance of capnography for early diagnosis of gas embolism.

[Severe airway obstruction in 4 cases of postoperative obstructive hematoma]

Obstructive hematoma is a rare postoperative complication of surgery on the floor of the mouth or the anterior region of the neck and throat. The insidious development of symptoms, including agitation, which may be attributed to other causes, or their late appearance in hospital wards staffed by personnel unaccustomed to treating airway complications, means that the risk of hypoxia or respiratory failure is high. We describe four patients in whom the clinical picture began with agitation and dyspnea. Once the diagnosis was established, and after decompression of the surgical wound, tracheal intubation proved impossible in two patients, who required emergency tracheostomy. Two patients died from lack oxygen. Our review of the literature and experience have led to the following recommendations that may prevent avoidable deaths: a) the caregivers directly responsible for these patients should receive specific training; b) long-term monitoring and observation should take place in recovery units where early signs and symptoms can be detected and treated immediately; c) tracheostomy or 24-hour intubation should be considered when surgery in this anatomic region is highly invasive; d) consider that postoperative agitation in these patients is a symptom of hypoxia unless another cause is demonstrated; and e) the zone must be decompressed rapidly by opening the surgical wound and safeguarding the airway whenever obstructive hematomas present.

[Hemodynamic response to intubation with Macintosh and McCoy blades]

INTRODUCTION

The McCoy laryngoscope incorporates a modification of the Macintosh blade designed to facilitate laryngoscopy and difficult intubation. One end is articulated to allow better viewing of the larynx. Use of this blade reduces pressure placed on tissues in the supraglottic area during laryngoscopy.

OBJECTIVE

We designed this study to compare the hemodynamic repercussions of laryngoscopy and tracheal intubation (LTI) performed with either a Macintosh or the McCoy blade.

PATIENTS AND METHOD

Sixty ASA I-II patients scheduled for elective surgery requiring LTI were randomly assigned to 2 groups of 30 patients each. In both groups anesthetic induction was achieved with 0.04 mg.kg-1 midazolam, 0.002 mg.kg-1 fentanyl, 2 mg.kg-1 propofol and 0.1 mg.kg-1 vecuronium. In group 1 LTI laryngoscopy and intubation were performed using the Macintosh size 3 blade and in group 2 the McCoy size 3 blade was used. Systolic and diastolic arterial pressures and heart rate were recorded in each patient before anesthetic induction (baseline), 1 minute after induction and 5 minutes after start of LTI.

RESULTS

We found no significant differences between the 2 groups at any of the recording times.

CONCLUSION

The data obtained do not allow us to assert that there is any difference in hemodynamic response to LTI associated to type of blade used.