Comparative study between thoracic epidural block and general anesthesia for oncologic mastectomy

Abstracts

JUSTIFICATIVA E OBJETIVOS: A anestesia peridural torácica é utilizada com freqüência para procedimentos estéticos da mama e há poucos relatos de seu emprego para mastectomias com exploração axilar. O presente estudo comparou a técnica com anestesia geral em operações oncológicas da mama. MÉTODO: Quarenta pacientes foram divididas em dois grupos. No grupo peridural (n = 20) foi realizada peridural torácica com bupivacaína e fentanil associada à sedação com midazolam. O outro grupo (n = 20) recebeu anestesia geral convencional com propofol, atracúrio e fentanil e manutenção com O2 e isoflurano. Registraram-se no intra-operatório duração da operação, necessidade de complementação da anestesia ou da sedação e variáveis hemodinâmicas. No pós-operatório, foram registrados o tempo para alta da sala de recuperação pós-anestésica e hospitalar, a intensidade da dor e o consumo de analgésicos, os efeitos adversos e a satisfação com a técnica anestésica. RESULTADOS: Os grupos foram semelhantes e não houve diferença na duração da operação. Foi necessário complementar a sedação em 100% das pacientes que receberam anestesia peridural e em 15% foi complementada a analgesia com infiltração de anestésico local na axila. Houve maior incidência de hipertensão arterial no grupo da anestesia geral e de hipotensão entre as que receberam peridural. Ocorreu prurido em 55% das pacientes com anestesia peridural. Náusea (30%) e vômito (45%) foram mais freqüentes entre as que receberam anestesia geral. A analgesia pós-operatória teve melhor qualidade e o consumo de analgésicos foi menor no grupo da anestesia peridural. O período de internação também foi menor. CONCLUSÕES: A técnica peridural tem algumas vantagens com relação à anestesia geral e pode ser considerada uma opção para anestesia em mastectomias oncológicas com esvaziamento axilar.

ANESTESIA; ANESTESIA; CIRURGIA; CIRURGIA

SCIENTIFIC ARTICLE

Comparative study between thoracic epidural block and general anesthesia for oncologic mastectomy^*

Estudio comparativo entre la anestesia epidural torácica y la anestesia general en mastectomia oncológica

Sérgio D. Belzarena, TSA, M.D.

Anestesiologista da Santa Casa de Misericórdia de Santana do Livramento

Correspondence to

SUMMARY

BACKGROUND AND OBJECTIVES: Thoracic epidural block is frequently used for esthetic breast surgeries but reports of its use in mastectomies with axillary exploration are very rare. The present study compared this technique with general anesthesia in oncologic surgeries of the breasts.

METHODS: Forty patients were divided in two groups. The epidural group (n = 20) underwent epidural thoracic block with bupivacaine and fentanyl associated with sedation with midazolam. The other group (n = 20) underwent conventional general anesthesia with propofol, atracurium, and fentanyl, and maintenance with O₂ and isoflurane. Duration of the surgery, the need for intraoperative complementation of anesthesia or sedation, and intraoperative hemodynamic parameters were recorded. In the postoperative period, length of time until discharge from the recovery room and from the hospital, severity of pain, analgesic consumption, adverse effects, and satisfaction with the anesthetic techniques were recorded.

RESULTS: Both groups were similar and differences in the duration of the surgery were not observed. Complementary sedation was necessary in 100% of the patients who underwent epidural block and complementary sedation with infiltration of local anesthetic in the axilla in 15% of the patients in this group. The rate of hypertension was more frequent in the group of patients who underwent general anesthesia, while hypotension was more frequent in the epidural group. Pruritus was observed in 55% of the patients in the epidural group. Nausea (30%) and vomiting (45%) were more frequent in the general anesthesia group. The quality of postoperative analgesia was better in the epidural group, which also presented lower consumption of analgesics; the length hospitalization in this group was also lower.

CONCLUSIONS: Epidural block has some advantages when compared with general anesthesia and can be considered an anesthesia option in oncologic mastectomies with axillary lymph node dissection.

Key Words: ANESTHESIA: Regional, epidural; SURGERY: Oncologic, mastectomy

RESUMEN

JUSTIFICATIVA Y OBJETIVOS: La anestesia epidural torácica se utiliza a menudo para procedimientos estéticos de la mama y existen pocos relatos de su uso en mastectomías con exploración axilar. El presente estudio comparó la técnica con anestesia general en operaciones oncológicas de la mama.

MÉTODO: Cuarenta pacientes que se dividieron en dos grupos. En el grupo epidural (n = 20) se hizo una epidural torácica con bupivacaína y fentanil asociados a la sedación con midazolam. El otro grupo (n = 20), recibió anestesia general convencional con propofol, atracurio y fentanil y mantenimiento con O₂ e isoflurano. En el intraoperatorio y durante la operación, se verificó la necesidad de complementación de la anestesia o de la sedación y variables hemodinámicas. En el postoperatorio fue registrado el tiempo para el alta de la sala de recuperación postanestésica y hospitalaria, la intensidad del dolor y el consumo de analgésicos, efectos adversos y la satisfacción con la técnica anestésica.

RESULTADOS: Los grupos fueron similares y no hubo diferencia en la duración de la operación. Se hizo necesario complementar la sedación en un 100% de las pacientes que recibieron anestesia epidural y en un 15% fue complementada la analgesia con infiltración de anestésico local en la axila. Hubo una mayor incidencia de hipertensión arterial en el grupo de la anestesia general y de hipotensión entre las que recibieron epidural. Ocurrió prurito en un 55% de las pacientes con anestesia epidural. Náusea (30%) y vómito (45%), fueron más frecuentes entre las que recibieron anestesia general. La analgesia postoperatoria tuvo una mejor calidad y el consumo de analgésicos fue menor en el grupo de la anestesia epidural. El período de internación también fue menor.

CONCLUSIONES: La técnica epidural tiene algunas ventajas con relación a la anestesia general y puede ser considerada una opción para la anestesia en mastectomías oncológicas con vaciado axilar.

INTRODUCTION

The incidence of breast malignant neoplasia, as well as the need of surgical treatment, has increased probably due to prevention campaigns and modern diagnostic tools.

Nowadays, surgical intervention is more conservative but in most cases partial or total mastectomy associated with axillary exploration to remove lymph nodes for staging or immune-chemical testing is still necessary.

General anesthesia, almost always combining intravenous and inhalational agents, is the technique normally used for this procedure. The downside of general anesthesia includes inadequate pain control due to a lack of residual analgesia, and a high incidence of nausea and vomiting, increasing the length of hospitalization ¹. Other controversial effects of general anesthesia in oncologic patients are related with depression of the immune system ².

Thoracic epidural block is frequently used in plastic surgeries of the breasts ^3-6 and postoperative analgesia of thoracotomies, and there are also a few reports on its use in oncologic surgeries of the breasts ^9,10.

The present study compared general anesthesia and thoracic epidural block in female patients undergoing oncologic surgeries of the breast with axillary exploration, evaluating intraoperative hemodynamic parameters, postoperative analgesia, and side effects, such as nausea and vomiting.

METHODS

This study was approved by the Ethics Commission of the hospital and patients were enrolled after signing an informed consent. An open study with patient distribution in each group according to a computer-generated chart was chosen due to the characteristics of the evaluation. Forty patients, divided in two groups, participated in the study. Infection of the puncture area was considered an exclusion criterion for thoracic epidural block and, if present, the patient was excluded from the study.

Venipuncture with a Teflon catheter, and monitoring with ECG, hemoglobin saturation (SpO₂), and non-invasive blood pressure were standard for every patient. Oxygen, 5 L.min^-1, was administered via a face mask. In the operating room, patients were sedated with intravenous midazolam 2 mg, and fentanyl 25 µg; 1 g of cephalothin, 20 mg of tenoxicam, and 10 mg of dexamethasone were also administered intravenously. Afterwards, patients underwent general anesthesia or epidural block, according to the group they were assigned to.

Epidural block: the patient was placed on lateral decubitus, the area was cleaned, and the T_4-5 intervertebral space, or the one closer to this space considered to be an easier access, was anesthetized. A Tuohy 18G needle was introduced and the epidural space was identified by the loss of resistance technique. Twenty mL of 50% enantiomeric excess bupivacaine (S75-R25) at a concentration of 0.375%, associated with 100 µg of fentanyl were administered in 5-mL fractions. The patient was then placed in dorsal decubitus and, after testing the quality of anesthesia (adequate analgesia from the lower border of the clavicle to the inferior costal margin), the surgery was initiated. Whenever necessary, supplementary doses of midazolam 1 mg were administered for sedation. If anesthesia was inadequate after 10 minutes, the patient underwent general anesthesia. If the patient experienced pain or discomfort during axillary exploration, the surgeon infiltrated the area with 3 to 5 mL of the same local anesthetic.

General anesthesia: with the patient breathing O₂ via a face mask, propofol (100 to 140 mg), fentanyl (100 to 150 µg), and atracurium (30 to 35 mg) were administered and the patient was then intubated. Anesthesia was maintained with isoflurane in 100% O₂ and additional doses of atracurium (10 mg) whenever necessary. At the end of the surgery, the neuromuscular blockade was reversed with atropine and neostigmine.

During the surgery, the surgion evaluation of the quality of anesthesia, the need of supplementary sedation, hemodynamic changes (tachycardia, represented by a heart rate greater than 100 bpm; bradycardia, heart rate below 60 bpm; hypotension, defined as a 20% drop in baseline blood pressure; and hypertension, a 20% increase in baseline blood pressure), and other intercurrences, such as pruritus, nausea, and vomiting were recorded as well as the length of the surgery.

Postoperatively, the length of stay in the recovery room and the length of hospitalization were recorded. Quality of analgesia was evaluated using a verbal scale that included very strong pain, strong pain, mild pain, absence of pain, and the consumption of other analgesics were recorded. The incidence of nausea and vomiting was also recorded and at the time of discharge patients were questioned about their degree of satisfaction with the anesthetic technique. Analgesia consisted of 20 mg of intravenous tenoxicam every 12 hours, and 1 g of dypirone and 50 mg of tramadol were administered intravenously whenever tenoxicam was not enough.

For the statistical analysis, the Kruskall-Wallis test was used for interval measurements, the Chi-square test was used for categorical parameters, and paired Student t test for continuous measurements, using a p < 0.05 as significant. Data are shown as mean ± standard deviation in absolute numbers or proportions.

RESULTS

The demographic data showed no differences between both groups (Table I).

The length of surgery was similar in both groups, as well as the incidence of tachycardia or bradycardia. Hypotension was more frequent in patients who underwent epidural block, while hypertension was more frequent among those who underwent general anesthesia. All patients needed supplementary sedation, most of them before the beginning of the surgery and without concomitant complains of pain. Most of them received up to 2 mg and four patients received three doses of 1 mg of midazolam.

During the surgery, nausea and vomiting were not observed and three patients needed supplementary axillary anesthesia (Table II).

Postoperatively, the incidence of pruritus was greater in the epidural block group and that of nausea and vomiting was lower. The intensity of pain and consumption of supplementary analgesics were lower in patients in the regional block group. Supplementation with tramadol was used only in patients in the general anesthesia group, while pain was easily controlled with anti-inflammatories in the other group. The length of stay in the recovery room and hospitalization were lower in the epidural group; 12 patients in this group were discharged from the hospital in 24 hours or less, while only 2 patients who underwent general anesthesia were discharged in the same period. Thus, 36 hours after the surgery, eight and 18 patients respectively were still in the hospital. Satisfaction with the anesthesia was similar in both groups (Table III and ^IV).

DISCUSSION

This study demonstrated that it is possible to use single dose thoracic epidural block for oncologic mastectomies with axillary emptying, and that this technique has some advantages when compared with general anesthesia.

The incidence of breast cancer has been increasing and, currently, it is the most common cancer in females. Surgery is the main treatment and the current tendency is towards less extensive procedure (sectorectomies, localized resections, etc) with axillary dissection for removal of lymph nodes to guide further treatment. In this situation, the anesthetic technique should provide adequate intraoperative anesthesia and good postoperative analgesia without collateral effects and with the minimum hospitalization time.

Intraoperatively, the quality of anesthesia was adequate in most patients, despite the need for complementation with the administration of local anesthetic in the axilla in three patients. In those patients, dissection went as far as the second level and the surgery was not compromised. A problem of thoracic epidural block is related with thoracic and axillary innervation. On the surface, the territory of the fourth cervical root is above the second thoracic dermatome, and the lower cervical roots give rise to the innervation of the axilla along with the second thoracic root. Thus, adequate blockade for the surface should include the fourth cervical root.

In the axilla, the blockade should include the cervical and the second thoracic roots; however, when dissection evolves for the second or third level (behind and medially to the pectoralis minor muscle), other cervical roots, up to above the fourth cervical root, are involved in the innervation. Thus, when it is tested, as in the present study, and the blockade is well established below the clavicle, the only certainty is that the level of anesthesia includes the fourth cervical root. The data of the present study shows that this level of blockade, on the fourth cervical root, can be consistently achieved after the administration of a single dose of local anesthetic with an opioid. Despite the large volume of the solution used, 20 mL, 75 mg of anesthetic is not considered a high dose, and this dilution was used because this procedure does not require intense muscle relaxation. A recent study ¹¹ demonstrated that the median thoracic approach, such as the one used in the present study, tends to present greater caudal dispersion of the local anesthetic, justifying the use of larger volumes.

A high blockade can affect hemodynamic and respiratory parameters, which was not detected in our patients. The incidence of hypotension was high (60%); however, the reduction in blood pressure was not clinically important and it was easily controlled with low doses of vasopressor. Medium thoracic block is considered to cause hypotension by inhibiting sympathetic cardiac fibers. This did not occur and, since other studies have similar results ^4,6,9, the data suggest that the problem should be studied further. According to the monitoring used, respiration was not affected and there are studies demonstrating that the thoracic epidural block can be safely used in this type of surgery, even in patients with asthma or obstructive pulmonary disease ¹². The cervical approach that blocks up to the second cervical root causes respiratory changes, decreasing diaphragmatic function ¹³, which is related with the concentration of the local anesthetic used.

All patients requested more sedation and, since most made this request before the beginning of the surgery, one can assume that the initial sedation planned was not enough and that several factors were responsible for this result. Higher doses divided in several administrations are probably more adequate, considering that, according to the weight of the patients, the amount of midazolam and fentanyl administered before the blockade was low.

The multimodal technique of postoperative analgesia using local anesthetic and spinal opioid and intravenous anti-inflammatory had better results; patients did not complain of very strong or strong pain and the request for supplementary analgesic was lower. Tramadol was not used in patients in the epidural block group. Adequate control of pain in this situation is important since it makes for a better postoperative period and early hospital discharge, and can have a long-term effect, decreasing complications such as chronic pain ^14,15. Prior administration of tenoxicam can be advantageous, as suggested by another study¹⁶.

Regional block has a lower incidence of nausea and vomiting, when compared with general anesthesia, which has been demonstrated in several procedures and studies ¹⁷. In the present study, the incidence of this complication in the general anesthesia group is comparable to that reported in other studies that used only general anesthesia and in those comparing general anesthesia and regional block. The only study ⁹ that made a comparable evaluation showed an incidence of 10% of nausea and vomiting among patients undergoing epidural block, which is considerably lower than the incidence seen in general anesthesia, but it still suggests that there are other factors involved in the development of this problem. It is speculated that it could be due to the spinal administration of opioid (fentanyl) for sedation. It would be interesting to study whether the association with anti-emetics can reduce the incidence even further.

Pruritus, most likely due to the spinal administration of fentanyl, was the most frequent adverse effect. Since pruritus was not severe, specific treatment of this occurrence was not necessary.

The length of stay in the recovery room and in the hospital was smaller in the epidural block group. This is important since the patient can readily return to her family and social environment and can decrease the cost of the procedure, although this was not specifically assessed in this study.

To conclude, single-dose thoracic epidural block associated with local anesthetic and opioid was an adequate option for mastectomy. Among its advantages, the quality of postoperative analgesia, lower incidence of nausea and vomiting, and shorter recovery time, with the consequent early hospital discharge, can be mentioned.

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*

Recebido do Serviço de Anestesiologia da Santa Casa de Misericórdia de Santana do Livramento, RS

Publication Dates

• Publication in this collection
  14 Nov 2008
• Date of issue
  Dec 2008

History

• Accepted
  18 July 2008
• Received
  05 Aug 2007