Epidural analgesia for pain relief in thoracic surgery.

The effectiveness and adverse effects of continuous epidural analgesia was studied in 104 patients undergoing thoracic operations at Siriraj Hospital. Patients were divided into 3 groups according to the type of surgical approach and the technique of epidural analgesia. Group 1 patients (n = 72) received thoracic epidural block using bupivacaine and morphine combined with light general anesthesia for exploratory thoracotomy; group 2 patients (n = 21) received the identical anesthetic technique, the operation was achieved through median sternotomy; group 3 patients (n = 11) had a similar type of operation to group 1, the anesthetic technique was lumbar epidural block using morphine and combined with light general anesthesia. Continuous epidural morphine infusion was given 0.1-0.4 mg/h during postoperation in all patients for providing adequate pain relief. The results revealed that a 10 cm visual analogue scale (VAS) pain scores were satisfactory and comparable in all groups. Lumbar epidural patients consumed a significantly larger dose of morphine than thoracic epidural groups (P < 0.01). Intraoperative hypotension occurred 43.05 per cent and 19.05 per cent in group 1 and 2, but none was found in group 3 (P < 0.05). Postoperative respiratory depression was found 54.16 per cent in group 1, 33.33 per cent in group 2 and 9.09 per cent in group 3 (P < 0.05), and was mostly mild to moderate, except three patients in group 1 and one in group 2 who needed mechanical ventilatory support. There were no differences among the groups in the incidence of nausea/vomiting and pruritus. It is concluded that both thoracic and lumbar epidural morphine provide excellent postthoracotomy pain relief, whereas, respiratory depression is more common with thoracic than lumbar epidural morphine.

Hemodynamic responses to captopril during splenectomy in thalassemic children.

Splenectomy in beta-thalassemic children is frequently accompanied by perioperative hypertension which occasionally is followed by convulsion. The efficacy of captopril in attenuating the hypertensive response to splenectomy was investigated in 82 thalassemic children. The control group, consisting of 40 patients, received intravenous furosemide (1 mg/kg) preoperatively; whereas, 42 children were randomly allocated into 2 groups to receive oral captopril (0.7 mg/kg) or a combination of captopril (0.7 mg/kg) and furosemide (1 mg/kg) before the operation. Before anesthetic induction, both systolic and diastolic arterial pressures in the captopril and the combined groups were significantly lower than the furosemide group (P < 0.001), whereas, the heart rates in all groups were comparable. Changes in arterial pressure in response to the operation were significantly smaller in the combined group when compared with the other two groups (P < 0.001). Immediate postoperative hypertension requiring additional management occurred in 20 per cent of the furosemide group, and 14.3 per cent in the other two groups. One patient in the combined group had a convulsion in association with hypertension. The authors conclude that captopril combined with furosemide effectively controls intraoperative hypertension in thalassemic children undergoing splenectomy; however, postoperative hypertension remains common, and needs appropriate treatment immediately.

Combined thoracic epidural with light general anesthesia for thymectomy in myasthenia gravis.

Forty-seven myasthenia gravis patients undergoing transsternal thymectomy were allocated into 2 groups. Group 1 which consisted of 27 patients was anesthetized using the balanced technique, while 20 patients in group 2 received the combination of thoracic and balanced anethesia. The ventilation was controlled through the endotracheal tube in both groups. The extubation criteria after performing the surgery were good consciousness, adequate muscle strength and adequate respiration. There were 29.2 per cent in group 1 but 77.8 per cent in group 2 (P = 0.002) with successful extubation immediately postoperation. Morphine 15.4 +/- 5.3 mg intramuscularly in group 1, and 6.5 +/- 1.2 mg epidurally in group 2 (P < 0.001) was given for postoperative analgesia. Adequacy of respiration was observed postoperatively in the intensive care unit (ICU). Group 1 patients required 76.9 per cent of further ventilatory support for the period of 37.11 +/- 39.54 hours and duration of the ICU stay was 65.52 +/- 85.84 hours, whereas, the patients in group 2 showed significantly different results, which were 15.8 per cent of ventilatory support (P = 0.002) for 10.33 +/- 6.03 hours (P = 0.014) and 22.8 +/- 8.06 hours for staying in ICU (P = 0.021). This study demonstrated that the combined thoracic epidural with light general anesthesia provides excellent intraoperative anesthesia together with postoperative analgesia, which reduces the need for postoperative respiratory support, as well as decreases the hospital cost.

Does furosemide prevent hypertension during perioperative splenectomy in thalassemic children?

Hemodynamic changes of 50 thalassemic children who had splenectomy under general anesthesia were compared to 40 identical patients who, in addition, received intravenous furosemide 1 mg/kg immediate preoperation. During the anesthetic process, both groups showed a significant increase of heart rate, systolic and diastolic blood pressure more than the preanesthetic values. Hemodynamic variables in the furosemide group declined toward normal range on termination of anesthesia, whereas, the other group's variables were still significantly higher than their control. During the first 24 hours postoperatively, 20 per cent of the furosemide group had blood pressure rising higher than 130/90 mmHg, while 18 per cent was observed in the other group. Antihypertensive drugs were given to reduce the blood pressure in both groups. None of the patients in the furosemide group demonstrated any abnormal neurological symptoms, but 3 out of 50 patients in the other group developed convulsion. We, therefore, conclude that circulatory volume reduction with furosemide does not prevent hypertension during perioperative splenectomy in thalassemic children. However, it's role in prevention of neurological abnormalities needs to be further investigated.

Intraoperative transesophageal echocardiography: preliminary experience at Siriraj hospital.

In order to evaluate the result of intraoperative TEE monitoring for cardiothoracic surgery, 113 patients were involved in this study. They included 65 males and 48 females, with an average age of 48.8 +/- 16.6 years, ranging from 10 to 74 years. The pre-operative diagnoses consisted of 41.6 per cent coronary artery disease, 34.5 per cent valvular disease, 12.4 per cent congenital heart disease, 8 per cent aortic aneurysm or aortic dissection, and 3.5 per cent of miscellaneous. The TEE appeared to provide accurate information by beating to changes in the left ventricular preload and contractility in all patients. The severity of valvular dysfunction, intracardiac air/mass, Swan Ganz catheter position, sites of congenital heart defect and aortic dissection were either assessed or reconfirmed during the operation. The ease of TEE technique was satisfactory, since unsuccessful attempt was observed in only 1.8 per cent. One patient died from rupture of thoracic aortic dissection which was related to TEE probe insertion. These data suggest the favorable result of intraoperative TEE as a valuable tool for monitoring in cardiothoracic surgery. Although the technique is simple, special precaution must be observed for patients suffering from acute aortic dissection.

Hypertension perioperative splenectomy in thalassemic children.

We retrospectively studied the intraoperative hemodynamic changes in 100 thalassemic children undergoing general anesthesia for elective splenectomy. They were divided into 2 groups owing to the postoperative hemodynamic response. Eighty-four patients who had an unremarkable postoperative course were group 1, while 16 patients who developed immediate postoperative hypertension were group 2. There were no differences between the groups regarding age, body weight, sex, anesthetic time and operation time, except for the preoperative hematocrits of group 1 patients were slightly but significantly higher. Both groups similarly showed significant increase of the systolic as well as diastolic blood pressure throughout the anesthetic course. The heart rate was significantly increased at the beginning but declined to normal toward the end of the operation. Although none of the patients died postoperatively, all of group 2 patients needed aggressive treatment with diuretic and antihypertensive drugs. Despite the proper management, 3 of 16 patients developed convulsion and one of them had persistent neurological deficit. Since intraoperative and postoperative hypertension which commonly occur in these patients may lead to more serious neurological complications, the authors suggest that careful hemodynamic monitoring must be considered for all thalassemic children undergoing general anesthesia for splenectomy.

Acute hemodilution and autotransfusion in cardiac surgery: a comparison between rather healthy and high risk patients.

The effects of acute normovolemic hemodilution and autologous blood transfusion were studied in open heart patients, compared with rather healthy patients, NYHA class 1-2 and the high risk patients, NYHA class >2. Thirty-nine patients were involved in this study, 15 of them were identified as the rather healthy group while 24 patients belonged to the high risk group. Acute hemodilution was performed after anesthetic induction and before heparinization. Using an equal volume of polygeline 3.5 per cent (Haemaccel) to replace autologous blood removal, the number of patients who needed inotropic support to achieve normal arterial blood pressure was not significantly different between the groups. Following retransfusion of pump perfusate and autologous blood after the termination cardiopulmonary bypass, the number of patients who received additional homologous blood as well as the amount used percase were significantly less in the rather healthy patients. There was none in this group, but half of the high risk patients suffered from serious perioperative complications and one died. We conclude that this technique is safe and benefits blood conservation in rather healthy cardiac patients undergoing open heart surgery, but special precautions against risk should be considered in high risk patients.

Autologous blood and platelet-rich plasma reinfusion reduce post-operative blood and blood component therapy after cardiopulmonary bypass.

To study blood and blood component transfusion following reinfusion of platelet-rich plasma (PRP)/and autologous blood, 33 patients undergoing open-heart surgery were randomly divided into three groups. Group I comprised 13 patients as controls; group II, eight patients from whom were collected PRP 15-20 percent of plasma volume with Haemonetics; and group III, 12 patients from whom were collected PRP and whole blood (400-800 ml) before initiating standardized cardiopulmonary bypass. All of them had balanced anesthesia with thiopental, fentanyl, midazolam, atracurium and nitrous oxide in oxygen. After heparin reversal, PRP/PRP and autologous blood were reinfused in groups II and III, respectively. Recording of hematocrit, blood loss as well as the total number of transfusion was performed. In three groups, significant low levels of hematocrit were seen after cardiopulmonary bypass. Groups II and III has less blood loss after the operation as well as less banked blood and blood products transfusion (p<0.05). In conclusion, the reinfusion of PRP/PRP and autologous blood may serve as an effective method for reducing the amount of banked blood and blood products given in transfusion following cardiac operation.

Comparison of the hemodynamic changes following left atrial and peripheral venous administration of protamine during cardiac surgery.

The hemodynamic effects of left atrial administration of protamine for heparin reversal were compared with the peripheral venous route. One hundred patients, undergoing cardiac surgery, using cardiopulmonary bypass (CPB) at Siriraj hospital were randomly allocated into two equal groups of fifty. The preoperative and operative characteristics of the two groups were comparable. After the termination of CPB, protamine sulfate was administered over 3 minutes via the left atrium in group I, and via the peripheral vein in group II. The hemodynamics were measured before and 5, 15 and 30 minutes after protamine administration. There were no statistically significant differences in heart rate (HR), arterial blood pressure (BP), and central venous pressure (CVP) between the groups. After administrating protamine and adequate maintaining the preload in both groups of patients within the normal range, the HR did not change from immediate post CBP control values. The arterial BP was not changed for 5 minutes, thereafter, significantly elevated toward the preoperative baseline values. This data indicates that the left atrial injection of protamine does not provide any hemodynamic advantages over the peripheral venous administration.

The effects of protamine on hemodynamics and oxygenation during cardiac surgery.

The cardiopulmonary effect of protamine for heparin reversal was investigated in 100 patients, undergoing cardiac surgery, using cardiopulmonary bypass (CPB) at Siriraj hospital. Protamine sulfate at approximately equal to the amount of heparin was intravenously administered over 3 minutes after termination of CPB, together with rapid blood transfusion to establish the optimal level of central venous pressure. Following protamine administration, the heart rate was measured at 5, 15 and 30 minutes, and was not significantly different from the preoperative and post CPB values. The blood pressure was significantly decreased in the initial post CPB (P less than 0.05) and remained unchanged 5 minutes following intravenous protamine, thereafter, significantly rose to preoperative values. The arterial oxygen tension post CPB revealed shunting effect, but showed no significant change following protamine administration. The occurrence of cardiopulmonary adverse effect was not demonstrated in this study.