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Print version ISSN 0034-7094
Rev. Bras. Anestesiol. vol.56 no.4 Campinas Set./Aug. 2006
Current attitude of anesthesiologists and anesthesiology residents regarding total intravenous anesthesia*
Actitudes actuales de anestesiólogos y médicos en especialización con relación a la anestesia venosa total
Fernando Squeff Nora, TSAI; Marcos Aguzzoli, TSAII; Getúlio Rodrigues de Oliveira Filho, TSAIII
da Sociedade de Anestesiologia do Rio Grande do Sul
IIVice-Diretor Científico da Sociedade de Anestesiologia do Rio Grande do Sul
IIIResponsável do CET/SBA Integrado de Anestesiologia da SES-SC
OBJECTIVES: In the past, time, cost, information, training, and the evaluation
of the plane of anesthesia limited the acceptance of total intravenous anesthesia
(TIVA). The objective of this study was to determine the attitude of anesthesiologists
and other anesthesiology residents regarding total intravenous anesthesia.
METHODS: A questionnaire was sent to 150 anesthesiologists and 102 residents. The concordance (C) and disaccord (D) of each item were compared by z tests (consensus if p < 0.05).
RESULTS: There were 98 responses. The data represent the number of answers for each category. The majority of the participants agreed that the quality of the awakening stimulates the use of the TIVA (C/D = 86/8; p < 0.05); that the future depends on the development of drugs with a fast onset of action and immediate recovery (C/D = 88/5; p < 0.05); that they would like to use TIVA more often (C/D = 72/21; p < 0.05); and to have more information about TIVA (C/D = 77/14; p < 0.05). There was no agreement about the level of knowledge necessary to administer this technique when compared to inhalational anesthesia (C/D = 48/47); the majority of those who answered the questionnaire did not express any concerns with intra-surgical consciousness (C/D = 20/77; p < 0.05) but agreed that de availability of consciousness monitors would increase the use of TIVA (C/D = 64/25; p < 0.05). There was no consensus whether the need for infusion pumps (C/D = 52/40) and costs (CD = 52/39) limit its use.
CONCLUSIONS: The attitude regarding TIVA was predominantly positive. There was no consensus on the influence of the level of knowledge, of the infusion pumps, and of the costs on the use of TIVA.
Key Words: ANESTHETIC TECHNIQUES, General: intravenous; SCIENTIFIC METHODOLOGY: survey.
Y OBJETIVOS: Antiguamente, tiempo, costes, informaciones, capacitación
y evaluación de la profundidad de la anestesia limitaban la aceptación
de la anestesia venosa total (TIVA). El objetivo de este estudio fue el de determinar
las actitudes de anestesiólogos y médicos en especialización
con relación a la anestesia venosa total.
MÉTODO: Un cuestionario fue enviado a 150 anestesiólogos y 102 residentes. La concordancia (C) y discordancia (D) en cada ítem se compararon por pruebas z (consenso, si p < 0,05).
RESULTADOS: Hubo 98 respuestas. Los datos representaron números de respuestas por categoría. La mayoría de los participantes concordó en que la calidad del despertar estimula el uso de TIVA (C/D = 86/8; p < 0,05); que el futuro reside en el desarrollo de fármacos con un rápido inicio de acción y una rápida recuperación (C/D = 88/5; p < 0,05); que les gustarían utilizar TIVA con más frecuencia (C/D = 72/21; p < 0,05) y saber más sobre TIVA (C/D = 77/14; p < 0,05). No hubo consenso sobre el nivel de conocimiento para realizarla, comparada con la anestesia de inhalación (C/D = 48/47); la mayoría no expresó preocupación con la conciencia intraoperatória (C/D = 20/77; p < 0,05), pero concordó en que la disponibilidad de monitores de conciencia, aumentaría la utilización de TIVA (C/D = 64/25; p < 0,05). No hubo consenso sobre la necesidad de bombas de infusión (C/D = 52/40) y costes (C/D = 52/39) limitan su uso.
CONCLUSIONES: Las actitudes con relación a la TIVA fueron predominantemente positivas. No hubo consenso sobre las contribuciones del nivel de conocimiento, de los dispositivos de infusión y de los costes para el uso de TIVA.
Among the techniques of administering general anesthesia, balanced anesthesia, commonly related to the use of inhalational and intravenous drugs, has dominated the world for several years1. Currently, balanced anesthesia has divided the anesthesiologists' preferences with total intravenous anesthesia (TIVA)2. Although it is still underused, in a few European countries TIVA is already the technique of choice2.
Wright and Dundee3 published a study done in the United Kingdom evaluating the attitude regarding the use of TIVA, more specifically regarding the acceptance of the technique. The main causes of dissatisfaction were the infusion pumps available, costs, the absence of adequate and safe intravenous drugs, the difficulty to determine the anesthetic plane, and the lack of information and training.
Currently one can mention, among others, two changes that were responsible for the increase in the use of TIVA, namely the understanding and the development of pharmacokinetics models for new intravenous drugs, which made it possible the continual infusion of these drugs4 and the availability of consciousness monitors for peri-operatory use2,5,6.
Nora et al.7, using pre and post-tests applied in TIVA courses, identified some factors responsible for the difficulty to teach intravenous anesthesia. The lack of theoretical knowledge on the pharmacology of the drugs used and the difficulty to control the adequate anesthetic plane were indicated as limiting personal factors, while infusion pumps and its costs are mentioned in several events as limiting environmental or structural factors to the use of TIVA.
The changes in the attitude regarding learning new tasks can be influenced by the learning method and by the characteristics of the place or environment where the technique is practiced8.
The objective of this study was to determine the attitude of anesthesiologists and anesthesiology residents residents regarding total intravenous anesthesia.
The study was approved by the Institutional Ethics Committee. To select the population, we made a list of electronic addresses of anesthesiologists with the Título Superior de Anestesiologia (TSA Certificate of Anesthesiology) (n = 760) and of anesthesiology residents (AR) (n = 500) belonging to the roster of the Brazilian Society of Anesthesiology (www.sba.com.br). They were assigned numbers randomly generated electronically (MS Excell, Microsoft Corp., Bellvue, WA). Considering that the minimum acceptable concordance and disagreement to define consensus in each item of the questionnaire (P) is 70% of those who answered it, and assuming an error (e) of 5%, the number of answers to the questionnaires (n) was estimated in 84 (n = PQ/e2), where Q = 1 P9. Assuming that, in the worst-case scenario, only 20% of the total potential of 1,260 participants would answer the questionnaire8, we decided to invite the first 252 members of the list of randomly assigned numbers organized in crescent order. The invitation to participate in the study was made by an e-mail containing the link for the electronic questionnaire. The messages from the initial invitation that were returned were substituted successively by other members of the list until we reached the pre-established number of participants, resulting in the participation of 150 anesthesiologists and 102 AR. The electronic version of the questionnaire was created using the MS FrontPage 2000 (Microsoft, Bellvue, WA) and placed it in a website. The electronic version contained the study protocol and the consent form. The questionnaire contained 10 items (Chart I) measured in a 5-point Likert scale (5 = strongly agree; 1 = strongly disagree). It also contained places for the following demographic data: age, gender, length of time practicing anesthesiology, category (anesthesiologist or AR), and how often TIVA is used (always/frequently or rarely/never). Two reminder messages were sent to the participants at a 2-week interval. Data collection was interrupted two weeks after the last message.
The answers to the questionnaire were submitted to a psychometric assessment by reliability analysis, by the calculus of the Cronbach alpha coefficient, and factorial analysis by the principal components method. Answers on Likert levels 1 and 2 were grouped as disagreement and answers on Likert levels 4 and 5 were grouped as agreement and the respective percentiles were compared by z test for proportions. The consensus of the participants on each item was defined when p < 5%.
We obtained 98 answers (39%) to the questionnaire. Table I shows the demographics data of the sample.
The alpha Cronbach coefficient was 0.72. The adjusted mean correlation coefficient among the items in the questionnaire was 0.23. Item 8 (it is easy to learn TIVA) showed a low correlation with the other items (r = 0.09) and was taken out of the questionnaire. A structure of three factors explained the 58% variance in the answers to the items. Factor 1 (positive attitudes) had an eigenvalue of 2.86, being responsible for 32% of the variance and involved items 5, 7, 10, and 11. Factor 2 (worries) had an eigenvalue of 1.18, being responsible for 13% of the variance and involved items 1, 4, and 6. Factor 3 (limitations) had an eigenvalue of 1.15, being responsible for 13% of the variance and involved items 2 and 3. Table II shows the questionnaire formed according to the factorial structure described above, with the percentage of participants that agree and disagree with each item. There was no consensus among the participants regarding items 1 (to perform TIVA it is necessary to have more theoretical knowledge than for inhalation anesthesia; p = 0.88), 2 (I would probably use TIVA more often if it did not require the use of infusion pumps; p = 0.09), and 3 (I would use TIVA more often if the costs were not so high; p = 0.06).
The aim of this study was to measure the attitude of Brazilian anesthesiologists and anesthesiology residents regarding total intravenous anesthesia using a specially designed tool with reliable psychometric characteristics. The Cronbach alpha coefficient found (0.72) showed that the questionnaire had adequate reliability, therefore being useful to measure the attitude regarding intravenous anesthesia10. The questionnaire also showed a clear factorial structure that reflected the objectives of the items analyzed (enthusiasm with the technique, fears and concerns regarding its administration, and the limitations to its use due the characteristics of the working environment).
The data was collected through the Internet. Polls applied to health sciences allowed quick access to a large number of individuals, fast data gathering, and a remarkable economy of resources. However, both the external validity of the results and the answer rate could be hindered by several sources of error. Sampling errors might occur when just part of the target population is included; there might be enclosure errors when some units of the target population are excluded or disproportionably included; measurement errors may occur as a consequence of the structure of the research, characteristics of the Internet access program, situational variables, and characteristics of those who answered the questionnaire. The factors that influenced the response rates include the sensitive nature of the questions, lack of disposition to participate; lack of interest on the subject of the study; and lack of trust in the guarantee of confidentiality. The widespread use of anti-pop up programs by users and access providers can also block the access to invitation messages sent by e-mail. For those reasons, one must expect a low rate of answers11-13. To try to decrease those problems, the target population was limited to a group of individuals with common interests (in this case, the members of the Brazilian Society of Anesthesiology who made their e-mail available spontaneously), the questionnaire was tested previously to confirm the clarity of the items, the anonymity of the participants was guaranteed, reminder messages were sent, and we calculated previously the size of the sample necessary9,13. Among the positive factors regarding TIVA was the quality of the awakening, the trust in the future development of increasingly more adequate drugs, and the willingness to learn and perform the techniques of total intravenous anesthesia. In fact, the line of research of most companies indicates two aspects: the development of fast acting drugs and drugs that interfere as little as possible in the human body14.
Contrary to Wright and Dundee's research3, those who participated in our study demonstrated little concern with the possibility of intra-surgical awakening, but they agreed that the availability of consciousness monitors could contribute to the widespread use of total intravenous anesthesia. In fact, it has been shown that, after the institution of this equipment, the incidence of intraoperative awakening has had a reduction of approximately 77%5.
When Wright and Dundee's3 study was published, intravenous anesthetics had very different pharmacokinetics than the ones available nowadays, with long elimination half-lives, therefore, they were not suitable for continuous infusion. The half-life of the drugs used currently is much shorter and can be used in target-controlled infusions, allowing for fast induction and awakening from the anesthesia. The pharmacokinetics profile of the drugs used for continuous intravenous infusion has contributed for the diffusion of the technique, as well as for higher safety scores. These developments can explain the positive attitude of those participating in this study regarding the quality of the awakening of the current techniques of total intravenous anesthesia. The number of participants that mentioned the need for infusion pumps and the high cost of TIVA as limiting factors for its use is similar to those who disagree, showing a lack of consensus about the pharmacologic-economic aspects of total intravenous anesthesia. The costs of any anesthetic technique used nowadays, whether it is balanced or total intravenous anesthesia, do not exceed 6% of the total cost of a surgical procedure, being between 1% and 4% in the majority of the procedures15,16. The use of a questionnaire through the Internet showed to be a tool that facilitated the acquisition of answers, a useful and reliable tool to assess the attitude regarding intravenous anesthesia. The questionnaire identified specific areas in which there was no consensus among the anesthesiologists, which can be the objective of teaching and training.
We concluded that the attitude of anesthesiologists and residents regarding TIVA are predominantly positive; that the quality of the awakening was identified as a factor that stimulates the choice of the technique; that there is no consensus regarding concerns about the costs or about the availability of special equipment for its administration, suggesting that its pharmacologic-economic aspects have to be more disseminated; that, even though there are no concerns about the intraoperative awakening, the majority of anesthesiologists agree that, if consciousness monitors were easier to obtain, TIVA would be used more often; that there is interest in learning the technique as well as using the technique more often, suggesting that there is a place for courses, workshops, and other institutional tools in the field of intravenous anesthesia.
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Dr. Getúlio Rodrigues de Oliveira Filho
Rua Luiz Delfino, 111/902
88015-360 Florianópolis, SC
Submitted for publication
26 de julho de 2005
Accepted for publication 25 de abril de 2006
* Received from Hospitais Moinhos de Vento, Mãe de Deus de Porto Alegre e do CET/SBA Integrado de Anestesiologia da Secretaria de Estado da Saúde de Santa Catarina, Florianópolis, SC.