Ain-Shams Journal of Anaesthesiology

: 2017  |  Volume : 10  |  Issue : 1  |  Page : 140--143

Comparative study between sevoflurane and isoflurane on the perioperative and postoperative bleeding of adenotonsillectomy patients

Sanaa el Fawal, Wail Ahmed Abdelaal, Walid Hamed Nofal 
 Department of Anesthesiology, Intensive Care, and Pain Management, Faculty of Medicine, Ain-Shams University, Cairo, Egypt

Correspondence Address:
Wail Ahmed Abdelaal
Assistant Professor of Anesthesia and Intensive Care Ain - Shams University, 10 Bean Elmadares St . El-Khalafawy, Cairo


Objective The aim of this study was to compare the effects of volatile anesthetics isoflurane and sevoflurane on intraoperative and postoperative bleeding in patients who underwent tonsillectomy and adenoidectomy. Patients and methods A total of 64 children classified as American Society of Anesthesiologists class I or II, aged between 2 and 16 years, who were scheduled for tonsillectomy and adenoidectomy were included in this prospective randomized double-blind study. The patients were randomized into two groups, isoflurane group and sevoflurane group, with each including 32 patients. They received balanced general anesthesia with isoflurane concentration 1.2% or sevoflurane concentration 2%. In all patients, the amount of intraoperative blood loss in milliliters was measured by the suction bottle, as well as by weighing the used sponges for each patient. The duration of operation and recovery time were recorded. Results Isoflurane caused significantly lower amount of perioperative bleeding compared with sevoflurane (P=0.03). No significant difference was observed between the two groups in terms of age, BMI, and operation duration, Conclusion Anesthesia with isoflurane can lead to a lower amount of intraoperative bleeding compared with sevoflurane. Therefore, isoflurane may be preferred as an inhalational agent for maintenance of general anesthesia during tonsillectomy and adenoidectomy operations.

How to cite this article:
el Fawal S, Abdelaal WA, Nofal WH. Comparative study between sevoflurane and isoflurane on the perioperative and postoperative bleeding of adenotonsillectomy patients.Ain-Shams J Anaesthesiol 2017;10:140-143

How to cite this URL:
el Fawal S, Abdelaal WA, Nofal WH. Comparative study between sevoflurane and isoflurane on the perioperative and postoperative bleeding of adenotonsillectomy patients. Ain-Shams J Anaesthesiol [serial online] 2017 [cited 2021 Oct 23 ];10:140-143
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Full Text


Tonsillectomy and adenoidectomy are the most frequently performed surgical operations in pediatric patients. Blood loss needs to be controlled during surgery to ensure the operation proceeds smoothly and to reduce postoperative complications [1].

Pediatric tonsillectomy has to be performed under general anesthesia, with the use of volatile anesthetics like isoflurane or sevoflurane.

Tonsillectomy techniques have been blamed for the bleeding after tonsillectomy operations. Comparisons were made between the techniques, and the studies mostly emphasized the identification of the better technique [2].

Skillful surgery combined with careful management of blood coagulation will help in reducing unnecessary blood loss. The role of anesthetists in managing surgical blood loss has grown greatly in the past decade. Intraoperative blood loss varies according to the anesthetic agent used [3].

Platelets play an important role in hemostasis interactions of drugs used in anesthesia, with platelet function being implicated in aggravating the risk of perioperative bleeding [4].

Several studies on the effects of inhalational anesthetic agents on platelet function have been reported, and they state that sevoflurane inhibits human platelet aggregation and thromboxane A2 formation, possibly by suppression of cyclooxygenase activity, whereas isoflurane had no effect in the range of clinical concentrations [5],[6],[7],[8]. Moreover, sevoflurane, but not isoflurane, prolonged bleeding time in the humans [9].

As blood volume in children is low, even a small loss will result in dreaded complications, so blood loss measurement in pediatric surgery is important.

This study aimed to compare the effects of the volatile anesthetics isoflurane and sevoflurane on the amount of intraoperative and postoperative bleeding in patients who underwent tonsillectomy and adenoidectomy.

 Patients and methods

This prospective randomized double-blind study was conducted after approval by the Ain-Shams University Ethics Committee. Informed consents were obtained from all of the patients’ parents before enrollment.

A total of 64 patients between the ages of 2 and 16 years who were classified as American Society of Anesthesiologists physical status I and II and planned for elective tonsillectomy were included in the study. All patients had routine preoperative anesthesia evaluation. Exclusion criteria were any contraindication for general anesthesia, known allergy against sevoflurane or isoflurane, bleeding diathesis, suspicion of malignancy, aspirin or anticoagulant agent usage, and identification of an infection during systemic examinations.

The patients were randomly allocated into the sevoflurane or isoflurane groups (n=32 for each group) before surgery using a computer-generated random sequence of numbers. None of the patients were premedicated. On arrival to the operating room, an intravenous line was introduced under complete aseptic technique. The patients were monitored by ECG, noninvasive blood pressure measurement, peripheral arterial oxygen saturation, and end-tidal carbon dioxide.

After preoxygenation with 100% O2 10 l/min for 2 min, 1 µg/kg fentanyl, 5 mg/kg thiopental sodium (pentothal), and 0.6 mg/kg rocuronium bromide (esmeron) were used for the induction of anesthesia. After 2 min, orotracheal intubation was performed; volume-controlled ventilation with a tidal volume of 7 ml/kg and a respiratory frequency of 14/min was initiated.

For the maintenance of anesthesia, the patients were randomized into two groups, isoflurane group and sevoflurane group, each including 32 patients. The concentration of isoflurane was set at 1.2%, whereas the concentration of sevoflurane was set at 2%. Gas flow was continued until the end of the operation. At the end of the surgery, the neuromuscular blockade was antagonized with atropine (0.02 mg/kg) and neostigmine (0.04 mg/kg), and extubation was performed.

In all patients, the amount of intraoperative blood loss (estimated and recorded for each patient from the suction bottle, as well as by weighing the used sponges), the duration of operation, and recovery time were recorded. Recovery times were determined at 1-min intervals from discontinuation of the maintenance anesthetics to awakening (such as opening eyes on verbal command), extubation, and orientation to person and place. After anesthetic emergence and removal of the tracheal tube, the patients were transported to the postanesthesia care unit where they were clinically monitored for secretion, spasm, cough, agitation, and any bleeding.

Statistical analysis

Data were analyzed using statistical package for social science, version 21.0 (SPSS Inc., Chicago, Illinois, USA). Quantitative data were expressed as mean±SD. The power analysis of the study was performed on the basis of the amount of surgical bleeding (in ml).

Data were tested for normality using Shapiro–Wilk’s test. Independent samples t-test was used for normally distributed variables. Nonparametric tests such as Mann–Whitney U-test were used for the non-normally distributed variables. A P value less than 0.05 was considered statistically significant. Sample size was calculated as 32 patients in each group to achieve a power of 80% and an α error of 0.05.


None of the patients had any postoperative complications. Data were normally distributed for both groups as assessed by Shapiro–Wilk’s test (P>0.05) except the blood loss amount (P<0.05). Descriptive analysis revealed no significant differences between the two groups in terms of age, sex, duration of surgery, time to extubation, and time to discharge, as shown in [Table 1].{Table 1}

A Mann–Whitney U-test was run to determine if there were differences in blood loss in both groups. Distributions of the blood loss for both groups were similar, as assessed by visual inspection. Median blood loss for the isoflurane group was 75 ml, which was significantly less than the sevoflurane group (100 ml) (U=779 and P<0.001).

[Figure 1] showed the value of the median, outliers, and extreme values. Values 170 and 33 were called outliers, and 250 was called an extreme value. The minimum of isoflurane was not an outlier, so it was represented by the lower limb of the isoflurane figure.{Figure 1}

Data regarding the amount of bleeding in each group are showed in [Table 2].{Table 2}


The effects of isoflurane and sevoflurane, commonly used inhalation anesthetics for the maintenance of general anesthesia, on perioperative and postoperative bleeding are a focus of interest. The present study was conducted to test the difference in the amount of bleeding by the use of these two different inhalation anesthetics, and we found that isoflurane provides a better surgical view, by causing a lower amount of bleeding.

In children, physiological mechanisms are less adaptable. So, even a moderate blood loss will lead to hemodynamic instability and complications [10]. Thus, the estimation of blood loss for nearly all pediatric surgeries and a more widespread appreciation of the equivalent quantities for adults and children would do much to reduce dangerous imbalance of blood volume [11].

The role of anesthetists in managing surgical blood loss has grown greatly in the past decade. Intraoperative blood loss varies according to the anesthetic agent used [9]. Less bleeding from surgical site makes work easier for the surgeon. This causes the shortening of the duration of operation.

Measuring operative blood loss accurately and continuously is difficult especially in adenotonsillectomy. Several methods of estimation, such as calorimetric method of estimation (swab weighing technique) and repeated volume determination in the suction bottle or cotton and gauze, have been used. Measurement by swab weighing technique bears a fairly constant relation to estimations by blood volume and is the simplest and relatively the most accurate method [10].

The dissection skills of the operating surgeon also play a role in operative blood loss, and all patients were operated by the same surgeon and according to standard procedure.

The pharmacokinetic properties and recovery characteristics of sevoflurane have encouraged its use for maintenance of anesthesia. There are, however, a number of studies showing that sevoflurane has an inhibitory effect on coagulation and platelet aggregation [12].

Moreover, in previous in-vitro studies, platelet aggregation induced by ADP, epinephrine, arachidonic acid, prostaglandin G2, and thromboxane A2 receptor agonists was shown to be suppressed by sevoflurane [13]. The antiaggregate effects of sevoflurane are reversible [5]. However, isoflurane does not have an effect on the platelet response induced by ADP activation [14].

Studies that compared the intravenous propofol anesthesia with the inhalation anesthetics (isoflurane 0.4–1.0 vol%) showed that propofol did not provide a significant reduction in the amount of bleeding [15],[16],[17].

Nathan et al. [18] and Nakamura et al. [6] noticed a higher blood loss in patients undergoing ambulatory anesthesia with sevoflurane. They concluded that this increased blood loss is owing to the effect of sevoflurane on platelet function.


Maintenance of anesthesia with isoflurane can reduce blood loss and could give an acceptable surgical field compared with maintenance with inhaled sevoflurane in patients who underwent tonsillectomy and adenoidectomy.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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