The Chilean socio-ethno-genomic cline

Studies of the current Chilean population performed using classical genetic markers have established that the Chilean population originated primarily from the admixture of European people, particularly Spaniards, and Amerindians. A socioeconomic-ethno-genetic cline was established soon after the conquest. Spaniards born in Spain or Chile occupied the highest Socioeconomic Strata, while Amerindians belonged to the lowest. The intermediate strata consisted of people with different degrees of ethnic admixture; the larger the European admixture, the higher the Socioeconomic Level. The present study of molecular genomic markers sought to calculate the percentage of Amerindian admixture and revealed a finer distribution of this cline, as well as differences between two Amerindian groups: Aymara and Mapuche. The use of two socioeconomic classifications - Class and Socioeconomic Level - reveals important differences. Furthermore, Self-reported Ethnicity (self-assignment to an ethnic group) and Self-reported Ancestry (self-recognition of Amerindian ancestors) show variations and differing relationships between socioeconomic classifications and genomic Amerindian Admixture. These data constitute a valuable input for the formulation of public healthcare policy and show that the notions of Ethnicity, Socioeconomic Strata and Class should always be a consideration in policy development.

Management of postoperative pain in Spain: a nationwide survey of practice

BACKGROUND

Although the need for structured assessment and management of acute postoperative pain has been recognized, practices and responsibilities vary between and within hospitals and countries. We sought to determine current pain management practices in Spanish hospitals with and without acute pain services (APSs) or acute pain management programmes (APMPs) and compare them to practices reported for 1997-1998.

METHODS

Members of the Spanish Pain Society and APS/APMP heads were asked to respond to a survey. Responses were stratified by hospital size (< 200 or ≥ 200 beds) and APS/APMP presence or not. Categorical variables were described by percentages and the 95% confidence interval and continuous ones by the median and interquartile range.

RESULTS

Responses were received from 42.4% of hospitals with ≥ 200 beds (vs. 9.6% of the smaller ones). We fully analysed only data for the larger hospitals, 57.7% of which had an APS or APMP. Full-time pain physicians were on staff in 28.6% of large hospitals; 25% had full-time nurses. Patients received written information about postoperative pain in 34.8% of APS/APMP hospitals, and 72% of them recorded pain assessments routinely. Protocols reflected interdepartmental consensus in 80.8%; training in postoperative pain was organised in 54%. Respondents thought pain was well or very well managed in 46.4%. In APS/APMP hospitals the following results had improved: provision of written information for patients (58.5% vs. 0%), the recording of pain assessments (93% vs. 43.8%), consensus on a pain scale (92.5% vs. 41.9%), use of protocols (99.7% vs. 55.2%), analysis of quality indicators (52.8% vs. 15.4%), training (73% vs. 26.9%), and respondents' satisfaction with pain management in their hospital (68.6% vs. 9.5%).

CONCLUSIONS

The presence of an APS or APMP is associated with better results on indicators of quality of acute postoperative pain management.

[Factors determining patient satisfaction with the pre-anaesthesia consultation]

OBJECTIVE

To analyse patient satisfaction with care provided in the pre-anaesthetic consultation and its determining factors.

MATERIAL AND METHOD

An anonymous questionnaire was randomly distributed to patients attending a pre-anaesthesia clinic, which included 4 questions with 5 possible answers on a (very dissatisfied, dissatisfied, fairly satisfied, satisfied and very satisfied) categorical graduated scale related to punctuality, understanding of the information received, respectful treatment, and overall satisfaction. The fifth question was about the knowledge or the name of the anaesthesiologist who attended them. A binary logistic regression model was used, which identified the predictors of satisfaction, calculated the odds ratios, and their respective 95% confidence intervals.

RESULTS

A total of 4006 questionnaires were analysed, in which 99.2% (3966) of users rated as satisfied/very satisfied the question about the respectful treatment, 98.4% (3937) of the information received and understanding, 77.4% (3096) punctuality in attending, and 97, 6% (3909) overall satisfaction. Almost three-quarters (71%, 2844) did not know the name of the anaesthesiologist. Regression analysis associated the more satisfied with their treatment (OR 17.44; P<.0005) and the information received (OR 14.94, P<.0005), while punctuality (OR 5 40; P<.0005) was the factor that contributed less to the result.

CONCLUSION

In our population satisfaction in pre-anaesthesia consultation is due mainly to the communication skills of the anaesthesiologist.

[Influence of bispectral index monitoring on fentanyl requirements during total intravenous anesthesia for major gynecological surgery]

OBJECTIVE

To determine the influence that bispectral index (BIS) monitoring of hypnosis might have on need for analgesia during surgery under total intravenous anesthesia provided by bolus administration of fentanyl.

PATIENTS AND METHOD

Prospective, randomized and partially double-blind study of 40 patients undergoing major gynecological surgery under total intravenous anesthesia with propofol and fentanyl. In the BIS group (n = 20) propofol administration was adjusted to maintain BIS between 40 and 60. In the control group (n = 20) standard doses were given: 10 mg/kg-1/h-1 after anesthetic induction and for 5 minutes, 8 mg/kg-1/h-1 over the next 5 minutes and 6 mg/kg-1/h-1 throughout the rest of the operation. All patients received intravenous bolus administration of 150 or 75 microg of fentanyl to maintain analgesia whenever systolic blood pressure and heart rate increased 20% over baseline. We compared propofol and fentanyl requirements, intraoperative changes in BIS, and awakening from anesthesia.

RESULTS

Patient and surgical characteristics were similar in both groups. BIS monitoring allowed propofol administration to be decreased a mean 24% during maintenance of anesthesia, and this in turn was associated with a significant increase in mean dose of fentanyl (415 microg versus 253 microg in the BIS and control groups, respectively; p = 0.01). Mean values of BIS were higher in the BIS group (46.4 versus 42.2; p = 0.04) and patients in the BIS group awoke sooner (in 7.7 min versus 11.1 min; p = 0.01) and tended to report less pain upon arrival at the postanesthetic recovery room, although the difference was not statistically significant.

CONCLUSIONS

BIS monitoring of depth of hypnosis can influence requirements for fentanyl during total intravenous anesthesia by bolus dosing for maintenance of analgesia. This is probably due to changes in the administration of propofol made possible by BIS monitoring.

[The efficacy and safety of continuous epidural analgesia versus intradural-epidural analgesia during labor]

OBJECTIVE

To determine the efficacy and safety of intradural-epidural analgesia in comparison with continuous epidural analgesia during labor and childbirth.

PATIENTS AND METHOD

Forty-two women whose labor began spontaneously were enrolled and distributed randomly in two groups. The intradural-epidural analgesia group (IEA, n = 21) received 25 microgram of intradural fentanyl with 2.5 mg of isobaric bupivacaine with adrenalin, after which analgesia was maintained with epidural administration of one 8 mL bolus of 0.125% bupivacaine, followed by perfusion of a balanced concentration at a rate of 8 ml/h. Patients in the continuous epidural analgesia group (CEA, n = 21) were given 8 ml of 0.25% bupivacaine with adrenalin; the epidural perfusion of 0.125% bupivacaine and 1 microgram/ml of fentanyl was started at the same rate as in the IEA group. We recorded pain as assessed on a visual analog scale, extension of sensory and motor block, maternal hemodynamic constants, number of boluses of bupivacaine used, total doses of bupivacaine and oxytocin, instruments needed for childbirth, and side effects (pruritus, nausea and vomiting).

RESULTS

Analgesic efficacy during the first 30 minutes was greater in the IEA group. The total dose of bupivacaine, required top-up boluses, and the extension of sensory block at 30 minutes, one hour and two hours were also significantly less in the IEA group. The incidence of pruritus was higher in the IEA group. No significant differences were observed for other variables.

CONCLUSIONS

Intradural-epidural analgesia provides effective analgesia for labor, with rapid onset, reduced extension of sensory block, lower total doses of local anesthetics and few side effects.

The influence of the menstrual cycle in postdural puncture headache

BACKGROUND AND OBJECTIVES

We performed a preliminary study to analyze the influence of the menstrual cycle on the incidence of postdural puncture headache (PDPH).

METHODS

One hundred sixty female patients with regular menstrual cycles who received spinal anesthesia were observed. Based on the day within the menstrual cycle that they received the puncture, the patients were classified into period A (perimenstrual) or period B (postmenstrual). The possible relationship among headaches, lifestyle habits, and anesthetic technique, and the presence of PDPH were analyzed, as were the levels of female sex hormones with PDPH in comparison with a control group.

RESULTS

Seven cases of PDPH (4.3%) were observed--one within the perimenstrual group and six in the postmenstrual group. No significant differences were observed between the two periods or were there any differences in relating PDPH to the other variables analyzed.

CONCLUSIONS

According to our results, the menstrual cycle and hormonal levels may not have any influence on the appearance of PDPH in female patients, although a larger series is required to validate these results.

[Explicit and implicit memory during inhalation and intravenous anesthesia]

OBJECTIVE

Patients rarely report memory or knowledge of surgery after general anesthesia. During apparently adequate surgical anesthesia, however, information processing of high level functions, such as language comprehension and learning, can continue unconsciously. Our objective is to assess whether different anesthetic techniques (two inhalational and two intravenous) guarantee the absence of both types of memory.

PATIENTS AND METHOD

One hundred patients were randomly assigned to receive the following anesthetic procedures: desflurane/N2O (group 1), isoflurane/N2O (group 2), fentanyl/N2O (group 3) and total intravenous anesthesia (group 4). A cassette with the same music was played in all cases, and an order requiring a nonverbal response was given to 15 randomly chosen patients in each group. Response was evaluated at a visit 24 to 48 hours after surgery. Fifteen patients, therefore, constituted the study group for each anesthetic procedure, and 10 patients formed the control group. We assessed the presence of explicit memory in a structured interview, and implicit memory by way of the relation between the number of times the nonverbal order was obeyed and the time of the interview.

RESULTS

Explicit memory was absent in all patients. The presence of implicit memory was confirmed, however, in the isoflurane (p = 0.02) group. Significant differences between the isoflurane group and both the desflurane and total intravenous anesthesia groups (p = 0.03) were found.

CONCLUSION

Explicit memory was absent with all four anesthetic techniques used in our study. Implicit memory was more difficult to inhibit, however, with isoflurane/N2O.

[Satisfaction with locoregional anesthesia in women who had undergone cesarean section]

OBJECTIVES

To compare satisfaction with local-regional and general anesthesia in women undergoing cesarean, the possible influence of time of evaluation and recall of the anesthesiologist.

PATIENTS AND METHODS

Retrospective study performed in all women who delivered by cesarean in the 6 first months of 1997. The women were assigned to two groups according to type of anesthesia, local-regional or general. Their satisfaction with anesthesia was evaluated by questionnaire 48 to 72 hours after surgery and two weeks after release. Most items required discrete-point answers, including a satisfaction of a scale of 0 to 10. During the second interview we also evaluated satisfaction with the procedure and hospital in general, as well as recall of the anesthesiologist. Group homogeneity was based on demographic, sociocultural, obstetric and surgical variables.

RESULTS

In a context of high satisfaction with anesthesia, 189 (76%) of the 247 women receiving local-regional anesthesia gave high evaluations to the anesthesia (8.90 +/- 1.5; mean: 10), compared with 58 (24%) of those receiving general anesthesia (8 +/- 2; mean 8.5) (p = 0.001). Both groups were homogeneous except for the distribution of emergencies, which occurred more often in those receiving general anesthesia (p < 0.001). Women who had received local-regional anesthesia expressed greater willingness to repeat or recommend the technique (p < 0.001). The highest score in this group was from women receiving intradural anesthesia along with fentanyl for local anesthesia, with significant differences only in comparison to epidural anesthesia. The differences in responses between the first and second interview were scarce. The hospital received a lower evaluation than did either anesthesia or surgery (p < 0.001). The anesthesiologist, who was less well recognized than the obstetrician was remembered better among women receiving local-regional anesthesia (p = 0.008).

CONCLUSIONS

Local-regional anesthesia can improve levels of satisfaction over that of general anesthesia among women undergoing cesarean surgery, and contributes to maintaining recall of the anesthesiologist. These results may be related to the fact of being conscious during the birth of a child.

[Prophylaxis of intraoperative nausea and vomiting with sub-hypnotic dose of propofol during intradural anesthesia in cesarean section]

OBJECTIVES

To determine the preventive and therapeutic effect of 10 mg of propofol administered after delivery on the incidence of intraoperative nausea and vomiting (IONV) during intradural anesthesia for cesarean delivery.

PATIENTS AND METHOD

Controlled, randomized double blind study of 60 women (ASA I-II) receiving intradural anesthesia for elective or deferred emergency cesarean delivery. The propofol group received 10 mg i.v. immediately after fetal extraction. The control group received an equal volume of Intralipid. The presence of IONV after administration of the prophylactic bolus was treated with a second bolus, and if nausea had not subsided completely after two minutes, treatment was topped up with dehydro-benzoperidol.

RESULTS

The control group included 31 women and the propofol group 29, of whom 3 were excluded. Control variables were similar in the two groups. There were no significant differences in the incidence and severity of IONV between the two groups (22.5 versus 23%). The top-up antiemetic drug was used in the same number of patients in each group.

CONCLUSIONS

Although 10 mg propofol has been described as an effective direct antiemetic, episodes of IONV were neither prevented nor reversed by its use during intradural anesthesia for cesarean delivery.

[Effect of the local anesthetic on visceral pain in cesarean sections done under intradural anesthesia]

OBJECTIVES

To evaluate the influence of local anesthetic on the incidence and severity of visceral pain during cesarean section performed under subarachnoid anesthesia.

PATIENTS AND METHOD

This was a randomized double blind study of 90 parturients undergoing scheduled or emergency cesareans. The women were distributed among three groups according to local anesthetic used: 2% isobaric mepivacaine in group 1, 0.5% hyperbaric bupivacaine in group 2, and 0.5% isobaric bupivacaine with adrenalin in group 3. The total anesthetic dose was selected based on height, and pain was defined as silent and dull, or a sensation of pressure that was poorly defined, diffuse or referred to another area and accompanied or not by nausea and/or vomiting. Pain was assessed on a visual analog scale at various moments during surgery. Other variables recorded were metameric level of blockade, hemodynamic function and presence of nausea and/or vomiting.

RESULTS

One patient in each group was excluded. The incidences of visceral pain and 95% confidence intervals were as follows: 38% (23-56%) in group 1 and 10% (3.5-25%) in groups 2 and 3 (p = 0.002). The metameric level of blockade differed significantly among the groups. The highest level (T1-5) was reached in group 1 but level was the most consistent (T3-5) in group 2. Systolic arterial pressures in all groups were significantly lower than baseline levels 5 min after puncture and the decrease was greatest in group 3. The highest incidence (p = 0.01) of nausea and/or vomiting occurred in the isobaric bupivacaine group.

CONCLUSION

Use of hyperbaric bupivacaine offers advantages over the other techniques, as it assures more consistent attainment of metameric level, an incidence of visceral pain that is lower than that of isobaric mepivacaine, and fewer hemodynamic repercussions than isobaric bupivacaine with vasoconstrictor.

[Current situation of anesthesiology research in Andalucia and Extremadura. Comparative study with the rest of Spain]

OBJECTIVES

To examine the quality and quantity of scientific research in anesthesiology in Andalucia and Extremadura, comparing them with the rest of Spain.

MATERIAL AND METHODS

We conducted a retrospective study of publications (original research articles and clinical notes) by spanish authors whose abstracts appeared in the MEDLINE data base from 1990 to 1994. Quality of research design was assessed with the classification system of Fletcher and Fletcher, who categorize works and being either descriptive or analytical. Comparative analysis was in reference to the total number of anesthesiologists.

RESULTS

Anesthesiologists working in Andalucía and Extremadura make up 21.7% of the total number in Spain, yet fewer publications came from these regions (17%). The proportion of analytical designs, however, was significantly higher (60% versus 44%; p = 0.05). Publications were similar in other ways, though there was a higher proportion of articles from non-anesthesiologists in Andalucía and Extremadura (p = 0.02). Most publications adressed clinical questions.

CONCLUSIONS

Although there is less scientific publication coming from Andalucía and Extremadura in the field of anesthesiology, its quality is acceptable and seems to be improving.

[Comparison of changes in plasma concentrations of ACTH and beta-endorphin in cholecystectomy under general anesthesia and general plus epidural anesthesia]

OBJECTIVE

To study neuroendocrine response during cholecystectomy under general anesthesia with fentanyl and under general anesthesia with nitrous oxide plus thoracic epidural block, by determining plasma levels of ACTH and beta-endorphin.

PATIENTS AND METHODS

This was a prospective study of 2 randomly chosen groups of 7 patients each who were undergoing cholecystectomy. One group received general anesthesia with fentanyl at initial doses of 10 micrograms/kg-1 followed by perfusion of 5 micrograms.kg-1.h-1. The other group received general anesthesia with 60% nitrous oxide in oxygen combined with bupivacaine 0.5% for thoracic epidural blockade. Plasma levels of ACTH and beta-endorphin were determined at the following moments: A, upon arrival in the operating theater; B, after anesthetic induction and intubation; C, after incision; D, 30 minutes after start of surgery; E, after surgery but before extubation, and F, after arrival in the recovery room. Also recorded were mean arterial pressure and heart rate.

RESULTS

In both groups we found significantly higher levels of beta-endorphin throughout surgery. The increase was greater, however, in the group receiving combined anesthesia at moments D (p = 0.008) and E (p = 0.008). ACTH levels rose significantly during surgery (p = 0.004) in the combined anesthesia group, whereas there was only a slight increase in the group receiving only general anesthesia (p = NS). beta-endorphin levels increased proportionally more than ACTH levels during combined anesthesia. Hemodynamic stability was acceptable in both groups.

CONCLUSION

General anesthesia with fentanyl at the dose used in this study was more effective that combined anesthesia in mitigating the release of ACTH and beta-endorphin during cholecystectomy.

[Anesthetic implications in antiphospholipid syndrome. 2 clinical cases]

Anti-phospholipid syndrome, originally called anticardiolipin syndrome, is characterized by the presence of anti-phospholipid antibodies and a marked tendency to both arterial and venous thrombosis. The little information available on the implications of this syndrome for anesthesia derive from the recent description of the disease. We describe 2 patients, each with 1 of the 2 forms of antiphospholipid syndrome that have been described to date, and each needing surgery for a different reason. The first was a 24-year-old woman who was admitted to the hospital with diarrhea, fever and metrorrhagia in her fifth month of pregnancy. Blood tests revealed a weakly positive title of anti-cardiolipin antibodies. Steroid and antiplatelet therapy was begun. Delivery was at 35 weeks by elective cesarean with epidural anesthesia due to oligoamnios. The second patient was 52-year-old woman with a history of 13 miscarriages, cerebrovascular accident and deep venous thrombosis. She had been diagnosed as having systemic lupus erythematosus with anti-phospholipid syndrome and was receiving corticoid and antiplatelet therapy. She had been admitted on 2 occasions for epistaxis, purpura in the lower extremities and severe thrombocytopenia. The last condition did not respond well to immunosuppressant therapy and a splenectomy was therefore performed with the patient under general anesthesia. In both cases recovery was good in spite of the serious complications of anesthetic management.

[Comparative study of single-dose intradural anesthesia and continuous intradural anesthesia with or without fentanyl]

OBJECTIVE

To compare the hemodynamic effects, level of anesthetic blockade and advantages of single-dose versus continuous intrathecal anesthesia with hyperbaric bupivacaine with and without fentanyl.

PATIENTS AND METHOD

Prospective study in 45 patients under 65 who were scheduled for elective surgery of the lower abdomen, randomly divided into 3 groups. Group 1 and 2 received continuous intrathecal anesthesia with 10 mg hyperbaric bupivacaine; group 2 also received 25 mcg fentanyl. Patients in group 3 were given a single intrathecal dose of 15 mg hyperbaric bupivacaine. Mean arterial pressure and heart rate were recorded at baseline and 10, 20 and 30 minutes after the start of anesthesia. The level of block achieved was recorded after 10, 30 and 60 minutes. Hemodynamic changes, differences in blockade and side effects were analyzed.

RESULTS

Hemodynamic changes were greater in group 2 (fentanyl) than in groups 1 and 3 (p < 0.05), with group 3 showing the greatest degree of hemodynamic stability. Level of blockade was always higher in group 2, with significant differences at 30 min (p < 0.05). Seven and 5 reinjections by catheter were necessary in groups 1 and 2, respectively. Two patients in group 3 required general anesthesia when blockade was inadequate. Apart from pruritus in group 2 (40%), no side effects due to anesthesia were observed.

CONCLUSIONS

A single dose intrathecal anesthesia, produces less hemodynamic changes than a continuous intrathecal block. Nevertheless, continuous intrathecal block, allows the maintenance of the block as long as required. The association of fentanyl enhances the hemodynamic changes with no other beneficial effects.

[Postoperative mental confusion in the elderly with hip fracture. Perioperative risk factors]

OBJECTIVE

To determine the incidence of postoperative mental confusion and perioperative risk factors in elderly patients with femoral neck fractures.

PATIENTS AND METHODS

A prospective study of patients 65 years of age or older undergoing surgery for hip fracture with intradural anesthesia between March 1992 and August 1993. Although the total number of cases came to 162, only 50 patients were enrolled in the study: the rest were excluded mainly because of mental deficits presenting before surgery. Folstein's Mini-Mental State test was used to assess mental function. Risk factors analyzed were classified as preoperative, intraoperative (in the operating room and the recovery room) or postoperative (hospital ward).

RESULTS

Eleven (22%) patients showed signs of postoperative mental confusion. Simple analysis revealed a correlation between mental confusion and ASA (p = 0.01), neuropsychiatric history (p = 0.03) and preoperative hemoglobulin, red blood cell and urea nitrogen levels (p = 0.02). Multifactorial discriminant analysis indicated that patients with low red cell counts before surgery, high urea nitrogen and neuropsychiatric histories were more predisposed (p = 0.004) to mental confusion.

CONCLUSIONS

A high incidence of postoperative mental confusion is associated to pre-surgical factors. We therefore suggest that greater preventive and therapeutic efforts be directed preferably to preparation before surgery, especially in patients at high risk.

[Headache following dural puncture in pregnant patients at term. Comparative study with non-obstetric patients]

OBJECTIVES

To compare the incidence of postdural puncture headache after subarachnoid anesthesia with a 24G Sprotte needle among full-term obstetric patients as compared to non-obstetric patients.

PATIENTS AND METHODS

A total of 200 patients were studied prospectively, divided into 2 groups. Group 1 (n = 100) patients were delivered by cesarean section and group 2 (n = 100) patients underwent infraumbilical or traumatological surgery. All were ASA I-II and under 40 years of age. Hydration was accomplished with lactated Ringer's solution 400-1,000 ml before mid-line puncture. The anesthetic used in both groups was isobaric bupivacaine 0.5% with a vasoconstrictor. The incidence of arterial hypotension and accompanying symptoms was recorded; perioperative administration of vasoactive amines and anticholinergics and liquids administered was measured. Twenty-four to 48 hours later the patients were asked when they started walking and if postdural puncture headache was experienced.

RESULTS

Group 1 received smaller doses of bupivacaine (p < 0.05) and the incidence of arterial hypotension was greater (p < 0.01) and required increased administration of amines (p < 0.01) and perioperative fluid therapy (p < 0.001). No difference was found between the two groups either for time of start of ambulation or for incidence of headache, which was 1% in both groups.

CONCLUSIONS

The incidence of postdural puncture headache in obstetric patients is low and similar to that of non-obstetric patients when the 24G Sprotte needle is used.

[Synergism of midazolam and propofol in the induction of anesthesia]

INTRODUCTION

The purpose of this study was to determine the possible interaction of midazolam and propofol in the induction of anesthesia.

METHODS

A double-blind study of 90 ASA I-II women undergoing elective general surgery and gynecology was performed. The patients were divided into three groups of 30 patients receiving midazolam, propofol and a combination of both as the anesthesia induction agent. As a test of anesthetic induction the response to the verbal order of opening their eyes was evaluated. The dose-response curves for each group were determined by a logistic regression procedure while isobolographic analysis compared the actions of both agents separately and together.

RESULTS

The ED50 in the propofol group was 1.56 mg.kg-1 and that of the midazolam group was 0.24 mg.kg-1. In the midazolam-propofol group the ED50 of midazolam was reduced approximately a quarter (0.068 mg.kg-1) when associated to the half of the ED50 of propofol anteriorly obtained. Isobolographic analysis revealed that the conjunctive action of both drugs was synergic (p = 0.04).

CONCLUSIONS

Propofol potentiates the action of midazolam in anesthetic induction. Although this synergism also reduces with the association of thiopental-midazolam, the mechanism of action is not demonstrated as the same. Thiopental increases the affinity of the benzodiazepines for the GABA complex receptors which has not been described for propofol.