Impact of preoperative outpatient evaluation clinic on performance indicators

Abstracts

JUSTIFICATIVA E OBJETIVOS: O objetivo deste estudo foi avaliar os efeitos da implantação de Clínica de Avaliação Pré-Operatória Ambulatorial (APOA) em indicadores de desempenho do centro cirúrgico. MÉTODO: Durante cinco anos acompanhou-se, prospectivamente, o total de consultas APOA; o total de cirurgias realizadas; o total e os motivos de suspensão das cirurgias; as cirurgias realizadas em regime ambulatorial ou com o paciente internado; a taxa de suspensão das cirurgias e a média de permanência dos pacientes internados. Os motivos de suspensão das cirurgias foram divididos em causas médicas e administrativas. A taxa de suspensão foi apresentada em percentual, a média de permanência, em dias de permanência. Os demais indicadores foram apresentados como total. O estudo foi dividido em cinco períodos - Pré-APOA, APOA 1, 2, 3 e 4 - correspondendo, respectivamente, aos anos de 1998, 1999, 2000, 2001 e 2002. Em cada ano, a variação percentual dos indicadores foi comparada com o ano anterior e com o Ano Pré-APOA. Para verificar as interações entre os indicadores, foram estabelecidas razões. RESULTADOS: A Clínica de APOA, exceto para o total de cirurgias realizadas, apresentou melhora de todos os indicadores acompanhados. Essa melhora foi menor no início, crescente e mais significativa no ano APOA4. Houve diminuição do número total de cirurgias suspensas, principalmente por causas administrativas, diminuição da taxa de suspensão de cirurgias e da média de permanência, sendo essa diminuição crescente e mais acentuada no ano APOA4. Existe correlação (r = 0,977) entre a taxa de suspensão de cirurgias e a média de permanência dos pacientes internados. CONCLUSÕES: Existem alterações significativas nos indicadores. A melhora é gradual e progressiva, à medida que se avança em anos em relação ao desenvolvimento da Clínica de APOA, e repercute na melhoria dos indicadores.

ANESTESIA; CIRURGIA; INDICADORES

Impact of preoperative outpatient evaluation clinic...

SCIENTIFIC ARTICLE

Impact of preoperative outpatient evaluation clinic on performance indicators^*

Impacto de la implantación de clínica de evaluación pre-operatoria en indicadores de desempeño

Florentino Fernandes Mendes, TSA, M.D.^I; Ligia Andrade da Silva Telles Mathias, TSA, M.D.^II; Gastão Fernandes Duval Neto, TSA, M.D.^III; Alan Rodrigues Birck, M.D.^IV

^IMestre em Farmacologia pela FFFCMPA; Doutor em Medicina pela FMSCSP; Chefe do Serviço de Anestesiologia da Santa Casa de Porto Alegre

^IIMestre em Farmacologia pelo ICB-USP; Doutora em Medicina pela FMUSP. Chefe do Serviço e Disciplina de Anestesiologia da Santa Casa de São Paulo

^IIIDoutor em Medicina pela UNIFESP; Prof. Adjunto da Disciplina de Anestesiologia da UFPEL

^IVBioestatístico do Serviço de Anestesiologia da Santa Casa de Porto Alegre

^{Correspondence}

SUMMARY

BACKGROUND AND OBJECTIVES: This study aimed at evaluating the effects of implementing a Preoperative Outpatient Evaluation Clinic (POEC) based on operating center performance indicators.

METHODS: The following data were prospectively followed for five years: total POEC evaluations and surgeries performed; total and reasons for surgeries cancellation; inpatient or outpatient surgeries performed; procedures cancellation rate and mean hospital stay of admitted patients. Reasons for procedure cancellations were divided in medical and administrative reasons. Cancellation rate is presented in percentage. Mean hospital stay is presented in days. Other indicators are presented in total figures. The study was divided in five periods: Pre-POEC, POEC 1, 2, 3 and 4, corresponding, respectively, to the years of 1998, 1999, 2000, 2001 and 2002. For each year, indicators percentage was compared to previous year and to the year Pre-POEC. Reasons were defined to check interactions among indicators.

RESULTS: Except for total performed procedures, POEC has improved all tracked indicators. This improvement was low at the beginning and more significant in the year POEC 4. There has been decrease in the total number of cancelled procedures due to administrative reasons. There was also a decrease in procedures cancellation rate and mean hospital stay. These decreases were progressive and more marked in POEC 4. There is correlation (r = 0.977) between procedures cancellation rate and mean stay of admitted patients.

CONCLUSIONS: There are significant changes in indicators. Improvement is gradual and progressive as years go by with regard to POEC development, and positively affects indicators improvement.

Key words: ANESTHESIA, Evaluation; INDICATORS: performance evaluation; SURGERY: preoperative evaluation

RESUMEN

JUSTIFICATIVA Y OBJETIVOS: El objetivo de este estudio fue evaluar los efectos de la implantación de Clínica de Evaluación Pre-Operatoria Ambulatorial (EPOA) en indicadores de desempeño del centro quirúrgico.

MÉTODO: Durante cinco años se acompañó, prospectivamente, el total de consultas EPOA; el total de cirugías realizadas; el total y los motivos de suspensión de las cirugías; las cirugías realizadas en régimen ambulatorial o con el paciente internado; la tasa de suspensión de las cirugías y la media de permanencia de los pacientes internados. Los motivos de suspensión de las cirugías fueron divididos en causas médicas y administrativas. La tasa de suspensión fue presentada en porcentual, la media de permanencia en días de permanencia. Los demás indicadores fueron presentados como total. El estudio fue dividido en cinco períodos - Pre-EPOA, EPOA 1, 2, 3 4 correspondiendo, respectivamente, a los años de 1998, 1999, 2000, 2001 y 2002. En cada año, la variación porcentual de los indicadores fue comparada con el año anterior y con el Año Pre-EPOA. Para verificar las interacciones entre los indicadores, fueron establecidas razones.

RESULTADOS: La Clínica de EPOA, excepto para el total de cirugías realizadas, presentó mejora de todos los indicadores acompañados. Esa mejora fue menor en el inicio, creciente y más significativa en el año EPOA4. Hubo disminución del número total de cirugías suspensas, principalmente por causas administrativas, disminución de la tasa de suspensión de cirugías y de la media de permanencia, siendo esa disminución creciente y más acentuada en el año EPOA4. Existe correlación (r = 0,977) entre la tasa de suspensión de cirugías y la media de permanencia de los pacientes internados.

CONCLUSIONES: Existen alteraciones significativas en los indicadores. La mejora es gradual y progresiva, a medida que se avanza en años con relación al desarrollo de la Clínica de EPOA, y repercute en la mejoría de los indicadores.

INTRODUCTION

Economic pressures are forcing hospitals to decrease costs and invest in quality ¹. This has led to increased numbers of outpatient procedures or with admission in the day of the procedure ². So, it is not surprising that many medical centers are willing to develop preoperative evaluation programs aiming at improving quality of services and operating center deployment ³.

These programs have motivated several studies which are showing that the implementation of Preoperative Outpatient Evaluation Clinic (POEC) decreases costs ^3,4, procedures cancellations ^5-7 and mean hospital stay ^5,8,9. Every patient to be admitted is candidate to admission the day of the surgery and should be evaluated by POEC days or weeks before the procedure. POEC evaluations have decreased mean hospital stay and preoperative admission timing ^8,9. This has resulted in more admissions the day of the surgery and more patients submitted to outpatient surgeries ⁹.

POEC - Santa Casa

POEC - Santa Casa was created in September 1999 aiming at evaluating in outpatient regimen all surgical patients under the Public Health System (SUS) coverage, at decreasing the number of procedure cancellations and hospital stay length, at computerizing preanesthetic evaluation and at saving costs.

After surgery indication, all SUS patients are referred to POEC - Santa Casa where patients' history and physical evaluation, medical records and supplemental exams are reviewed by an anesthesiologist. Then, patients are approved for the proposed procedure or referred to additional clinical evaluation and, in this case, they should return to POEC - Santa Casa after the evaluation, to obtain approval.

This study aimed at evaluating the impact of a Preoperative Outpatient Evaluation Clinic (POEC - Santa Casa) on the behavior of surgical center performance indicators.

METHODS

After the Medical Ethics Research Committee, da Irmandade Santa Casa de Misericórdia de Porto Alegre approval the study began.

From January 1, 1998 to December 31, 2002, data to track operating center-related performance indicators were collected by the Controller's department. Tracked indicators were: 1) number of POEC evaluations/year; 2) number of procedures performed/year; 3) number of procedure cancellations/year; 4) reasons for procedure cancellations (medical and administrative reasons)/year; 5) number of outpatient and inpatient procedures/year; 6) rate of procedure cancellations/year; 7) mean hospital stay/year.

The number of POEC evaluations was collected by the Evaluations Management System. Number of surgeries, total and reasons for procedures cancellations were obtained from the Operating Center Management System. Cancelled surgeries were divided in medical reasons (lack of physical conditions or lab tests) and administrative reasons (patient not showing up, delays, insufficient beds, lack of material, absence of surgeon, absence of anesthesiologist, refusal and others).

Total number of surgeries was collected by the Administrative and Financial System. Criteria to define outpatient procedures were hospital stay below 24 hours and billing by the Billing Sector as outpatient procedure. All other surgeries, including those started as outpatient procedures but whose patients had to be admitted, were considered inpatient procedures. These data were daily collected and fed into the Administrative and Financial System.

All patients scheduled for procedures in the operating center were included to calculate procedures cancellation rate. Procedures cancellation rate was represented by the ratio between the number of cancelled surgeries for medical and non-medical reasons, and total scheduled procedures for each month, being the result multiplied by 100 and expressed in percentage.

Mean hospital stay was calculated as from Admitted Patients Record System information and represents the ratio between total number of patients admitted at the end of each day, for each month, and total number of patients discharged during the same period, including deaths. Result was expressed in days.

Procedures cancellation rate was presented in percentage/year, and mean hospital stay in days/year; for such, arithmetic mean of means obtained in each month was calculated. Other indicators are presented as total/year after adding daily values for each year.

Ratio between POEC evaluations/number of surgeries per year was obtained. The same formula with changes in the numerator was used to obtain the ratio between total cancellations and total surgeries. Ratio between number of outpatient surgeries and total number of surgeries was obtained for each year. Results were multiplied by 100 and expressed in percentage.

To present and compare indicators' performance, this study was divided in five periods, as shown in chart I.

Brazilian Journal of Anesthesiology, 2005; 55: 2: 175-187

Impact of preoperative outpatient evaluation clinic on performance indicators

Florentino Fernandes Mendes; Ligia Andrade da Silva Telles Mathias; Gastão Fernandes Duval Neto; Alan Rodrigues Birck

So, pre-POEC was the year before POEC - Santa Casa implementation, POEC 1, was the first year of implementation (encompassing project design, logistics definition, training and start up) and POEC 2, 3 and 4 were following years of operation.

The impact of POEC - Santa Casa implementation was evaluated by percentage indicators variation in different years, which was presented with up to one decimal fraction. Expected result was percentage increase in total surgeries and outpatient procedures, with decrease in remaining indicators.

Statistical Analysis

Database was developed in MS Excel 2000. To prevent errors, data were typed by two independent operators and checked for consistency. The set of statistical programs SPSS 10.0 (Statistical Package for Social Science) was used for statistical analysis.

Adjustment test based on Chi-square distribution (c²) was used to check changes in indicators' behavior.

To check whether cancellations rate would differ during POEC years as compared to pre-POEC year we have consider it as a percentage of cancelled surgeries, we have assumed that variable distribution was binomial and Z test was used to compare percentages. POEC 1, 2, 3 and 4 percentages were compared to pre-POEC percentage. The same analysis was used for outpatient procedures percentage.

Mean hospital stay was tested as from Z distribution. In this case, once population's standard deviation was known, a hypothetical sample was tested with the same stay of pre-POEC year to check whether the sample would be significantly different from POEC 1, 2, 3 and 4.

P values refer to the probability of a hypothetical sample, with no difference in indicators along the years, be part of the population of studied data.

Percentage variation of parameters for each year was compared to pre-POEC year and to subsequent POEC year.

Ratio between procedures cancellation rate and mean hospital stay was evaluated by Pearson's correlation coefficient.

RESULTS

Operating center performance indicators results are shown in table I.

Brazilian Journal of Anesthesiology, 2005; 55: 2: 175-187

Impact of preoperative outpatient evaluation clinic on performance indicators

Florentino Fernandes Mendes; Ligia Andrade da Silva Telles Mathias; Gastão Fernandes Duval Neto; Alan Rodrigues Birck

There were 52,254 evaluations throughout the study in the POEC - Santa Casa (4,704, 16,757, 16,813 and 13,980 in POEC years 1, 2, 3 and 4, respectively). As compared to initial pre-POEC year, there has been decreased number of surgeries, increasing only in the last year, however remaining below baseline levels.

There has been progressive decrease in the number of procedures cancellation. There has been decrease in cancellations due to medical reasons already in the POEC - Santa Casa implementation year (POEC 1), but in the next year there has been considerable increase above baseline values, followed by progressive decrease until the last year. Cancellations due to medical reasons have decreased below pre-POEC values only during POEC 4 year. Cancellations due to administrative reasons have increased in POEC implementation year (POEC 1) as compared to pre-POEC year. There has been progressive decrease in subsequent years reaching values below baseline already in POEC 2 year.

The number of outpatient procedures has increased in POEC implementation year (POEC 1) as compared to pre-POEC year, but then it has oscillated for more or less without reaching POEC 1 year values. As to inpatient procedures, there has also been no pattern, with decrease during POEC 1 followed by increase, then decrease and increase in following years.

As compared to pre-POEC year, procedures cancellation rate has slightly increased in POEC 1, followed by gradual decrease in subsequent POEC years. Decrease from POEC 3 to POEC 4 was the most expressive.

There has been gradual decrease in mean hospital stay during the five years of study (6.2; 6.2; 5.9; 5.6 and 5 days of stay), with most significant decrease in POEC 4.

Parameters Behavior in Percentage Variation

Table II shows, for each parameter, percentage variation, for more (+) or less (-), of each year values as compared to pre-POEC year. It could be observed that, as compared to initial pre-POEC year, there has been decrease in procedure cancellations, especially due to administrative reasons, in the number of inpatient procedures, in procedures cancellation rate, and in mean hospital stay; there has been increase in number of outpatient procedures. Most expressive improvement was seen in POEC 4 year. Only the number of performed procedures has behaved differently from expected.

Brazilian Journal of Anesthesiology, 2005; 55: 2: 175-187

Impact of preoperative outpatient evaluation clinic on performance indicators

Florentino Fernandes Mendes; Ligia Andrade da Silva Telles Mathias; Gastão Fernandes Duval Neto; Alan Rodrigues Birck

Table III shows percentage variation, for more (+) or less (-), of performance indicators for each POEC year as compared to previous POEC year. There has been progressive improvement in the number of procedure cancellations, in the reasons for cancellation, in cancellation rate and in mean hospital stay. The same behavior was not observed with the number of procedures performed and the number of outpatient and inpatient procedures.

Brazilian Journal of Anesthesiology, 2005; 55: 2: 175-187

Impact of preoperative outpatient evaluation clinic on performance indicators

Florentino Fernandes Mendes; Ligia Andrade da Silva Telles Mathias; Gastão Fernandes Duval Neto; Alan Rodrigues Birck

Figure 1 shows percentage ratio between POEC evaluations and surgeries performed. There is correlation between procedures cancellation rate and mean stay of admitted patients (Figure 2).

Brazilian Journal of Anesthesiology, 2005; 55: 2: 175-187

Impact of preoperative outpatient evaluation clinic on performance indicators

Florentino Fernandes Mendes; Ligia Andrade da Silva Telles Mathias; Gastão Fernandes Duval Neto; Alan Rodrigues Birck

Brazilian Journal of Anesthesiology, 2005; 55: 2: 175-187

Impact of preoperative outpatient evaluation clinic on performance indicators

Florentino Fernandes Mendes; Ligia Andrade da Silva Telles Mathias; Gastão Fernandes Duval Neto; Alan Rodrigues Birck

When the number of cancelled procedures during different study years is related to the number of procedures performed (Figure 3) there is increase from pre-POEC to POEC 1 year and then percentage decrease during subsequent years. Most significant decrease was seen in POEC 4 year.

Brazilian Journal of Anesthesiology, 2005; 55: 2: 175-187

Impact of preoperative outpatient evaluation clinic on performance indicators

Florentino Fernandes Mendes; Ligia Andrade da Silva Telles Mathias; Gastão Fernandes Duval Neto; Alan Rodrigues Birck

DISCUSSION

The development of Preoperative Evaluation Clinics by anesthesiologists is a relatively new phenomenon and has been worldwide spread ⁸. Decreasing unnecessary exams ^1,3,8, increasing outpatient procedures or with admission the day of the surgery ^1,8,10, decreasing costs ^3,4,10-12, decreasing hospital stay ^3,9, improving quality of services ^3,4,9, improving patients' satisfaction ^3,13, preventing procedures cancellation ^6,10,11,14 and improving routines ¹⁵ are isolated or associated justifications for the implementation of such services.

Our results have shown that during POEC years 2, 3 and 4, the number of evaluations was higher than the number of surgeries (Table I and Figure 1). This is probably related to the number of patients with no clinical conditions or with no history and minimum lab tests when referred to POEC and who needed more than one evaluation to be ready for the procedure, or patients who, for any reason, were not submitted to the proposed procedure. Lack of surgical history ¹⁴, of minimum tests and patients' giving up the procedure ¹⁶ are evidenced in the literature. The adoption by POEC - Santa Casa of a routine to collect and perform lab tests, ECG and chest X-rays, in 2001, has probably contributed to the expressive decrease in evaluations observed in 2002, since this measure has improved the evaluation process, has added resolution to the service and has increased the percentage of patients approved for surgery with no need for a second evaluation due to lack of exams.

Fischer (1996) has reported that almost 90% of cancelled surgeries are decided in the day of the surgery and this cause a 97-minute delay between the end of one surgery and beginning of the other ¹¹. Cancellation rates vary among hospitals, depending on criteria to define cancellations and the method to collect data. There might also be major differences between retrospective and prospective studies, varying in the same institution from 6.6% when retrospective ¹⁷ to 13% when prospective ⁷.

In our study, there has been gradual and increasing reduction in surgeries cancellation during POEC years with more marked reduction in POEC 4 year. This has probably shown that POEC implementation and results, considering that paradigms are shifted and culture is changed, have gradual, continuous and increasing effects along time and that process improvements added to POEC - Santa Casa reflect on results since POEC 4 year presented the highest decrease in surgery cancellations.

In spite of POEC's major focus on medical evaluation and, when necessary, on clinical preparation of patients, the number of surgery cancellations for medical reasons has increased during the first years of POEC - Santa Casa, as compared to pre-POEC year. Although decreasing, cancellations for medical reasons have only reached a significant lower level in POEC 4 year as compared to pre-POEC year. This finding could be related to higher motivation, development of stricter criteria for clinical conditions, development of guidelines ², training, awareness that inadequate perioperative evaluation and preparation influence clinical outcomes ¹⁸, and better management standardization determined by POEC implementation to other anesthesiologists of the institution.

When the anesthesiologist is the POEC leader, there is higher commitment of the Anesthesiology department in doing the job and maintaining consistency ³. Decreased number of cancellations for medical reasons had already been shown since the beginning of POEC implementation ^6,11,19; this was the expected result, only observed in POEC 4 year.

On the other hand, cancellations for administrative reasons have progressively decreased since the beginning of POEC - Santa Casa, and have reached its peak in POEC 4 year, being one of the most significant results of this study. Similarly to what was shown in our study, the importance of decreasing cancellations for administrative reasons had already been shown by other hospitals ^7,20,21.

When a large number of observations is used, normal distribution is accepted as approximation of binomial ²⁷, thus justifying the use of Z test to compare percentages (percentage of outpatient procedures and surgery cancellations rate). Once standard deviation of mean hospital stay is known, and due to the large number of studied observations, the same was tested as from Z distribution. Results show that mean hospital stay during POEC years is significantly different as compared to pre-POEC year.

Ratio between outpatient and inpatient surgeries during the five studied years was maintained close to or below 20%. The encouragement toward outpatient procedures as from 2002 has not yet shown the desired effects. Data in the literature show that in the USA approximately 65% of surgeries are outpatient procedures ²². When there is increased outpatient procedures, costs are lower ^1,17,22, mean hospital stay is shorter ¹⁷, economic results are higher and there is less procedure cancellations ¹². In our study, decreased cancellation rates and mean hospital stay are not related to increased outpatient procedures, probably because these procedures are not so common in our hospital.

High cancellation rates are related to the method to define criteria to consider that surgery has been cancelled. Hospitals with more restricted cancellation lists report rates below 10% ^5,11 in contrast with hospitals, such as ours, including cancellations for all causes, including patients not showing up and cancellations due to administrative causes, with reported rates of 13% to 20% ⁷. Percentage decreases of 88% ¹¹, 64% ⁶, 60% ²³, 50% ²⁰ and 20% ¹⁷ in cancellation rates have been reported. In our study and considering just the last year, cancellation rate decrease was approximately 55.9%. These differences are probably related to criteria to define cancellations and to the level of organization and evolution of services when data were collected.

A potential risk of outpatient evaluation or admission the day of the surgery is longer hospital stay due to inadequate preoperative preparation ¹³. In a retrospective study with historical control, in patients submitted to major vascular surgeries, there has been 62.2% increase in admission in the same day for the carotid endarterectomy group, and of 50% for the peripheral revascularization group, with mean hospital stay decrease of 5.1 and 6.2 days, respectively. Postoperative stay has decreased 1.1 day for carotid surgery and was not changed for peripheral revascularization. There has been no change in cancellation rate and savings were of US$ 900 per patient ⁹. Surgical cancellation and delays in the day of the surgery are significant sources of frustration for patients and physicians ³, and decreased cancellation and hospital stay rates are major benefits associated to POEC ¹².

Savings associated to decreased lab tests, decreased specialized medical visits and decreased cancellation rates are significant however low, as compared to costs decrease associated to shorter hospital stay ¹³. So, interventions decreasing hospital stay may result in considerable savings ^9,12. There has been hospital stay length decrease throughout the five years of study however more marked in POEC 4 year. In correlating cancellation rates and mean hospital stay, it is observed that decreased cancellation rate decreases mean hospital stay, with no risk of increasing but rather being a major factor for its decrease (Figure 2). These are relevant results because in addition to improving processes they may determine increased productivity and considerable cost decrease, being this a major contribution of this study.

Another aspect with economic and service quality repercussion was the rate of cancelled surgeries as compared to performed surgeries. There has been expressive decrease in cancellations during POEC years and this decrease was more significant in POEC 4 year (Figure 3). This has contributed to improve processes and increase patients' satisfaction. A previous study has found 99%, 97% and 76% satisfaction rates of patients, anesthesiologists and surgeons, respectively, with POEC - Santa Casa ²⁴.

Our results have shown that all indicators were changed along POEC years as compared to pre-POEC year (Table I). Table II shows in percentages how these changes took place. Joint reading of these data allows us to state that POEC - Santa Casa, except for total performed procedures, has shown continuous improvement of all studied indicators. This improvement was lower in the beginning and more significant in POEC 4 year. These data are important for every hospital intending to implement POEC since preliminary although few results are already there, and indicators improve along the years.

In our institution, POEC has shifted paradigms, interfering with secular surgical culture, changing competencies to request clinical evaluation and preoperative tests, removing anesthesiologists from the operating room and increasing their participation and involvement in patients' preoperative care. According to Fischer (1999) this should increase productivity and efficiency, improve patients, surgeons and anesthesiologists satisfaction and give a view of future surgical clinic growth ³.

For some authors, every patient is candidate to admission the day of the surgery ²⁵. Data in the literature show that the implementation, through POEC, of programs for admission the day of the surgery or for encouraging outpatient procedures, contributes to decrease mean hospital stay ^9,17. Considering that 31% of hospital costs come from admitted patients ²⁶, the encouragement of outpatient procedures has yielded 20% to 50% cost reductions ^1,22.

Preoperative evaluation clinic is, in general, the first contact of the patient with the anesthesiology service and the hospital. During evaluation, smooth operations and organizational efficiency influence patients' perception of the quality of the service provided by the institution. A centralized evaluation clinic is a positive investment for the Anesthesiology Department because it has been recognized as a center to decrease perioperative costs, improve quality of service, implement guidelines and educational programs ². Any financial support provided by the hospital should be based on price, quality and value. Services centralization provides significant convenience for patients who do not need to visit several hospital sites to complete their evaluations, and represented significant improvements in studied indicators.

Parameters evaluated along the last five years allow concluding that there are significant changes in indicators. Improvement is gradual and progressive as years go by and reflects on indicators improvement. There is strong correlation between procedures cancellations rate and mean hospital stay of admitted patients.

REFERENCES

Submitted for punlication July 7, 2004

Accepted for punlication November 18, 2004

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^*

Received from Clínica de Avaliação Pré-Operatória Ambulatorial, Santa Casa Porto Alegre, RS

Publication Dates

• Publication in this collection
  01 June 2005
• Date of issue
  Apr 2005

History

• Accepted
  18 Nov 2004
• Received
  07 July 2004