Introduction[1]

For the first time, Gustave Kilian used rigid bronchoscopy to extract a foreign body from right main bronchus in 19^th century. This was performed on an awaked patient without any anesthesia. Then cocaine was used to facilitate this procedure and now GA is commonly used for rigid bronchoscopy.

Indications of rigid bronchoscopy include extraction of foreign bodies, management of massive hemoptysis, management of external pressure on tracheobronchial tree, and treatment of benign tracheal and bronchial   strictures  by  laser  (e.g.   Post- tracheal stenosis).  But extraction of foreign body is the most common indication for rigid bronchoscopy in children (1).

The main principles for optimal anesthesia for rigid bronchoscopy include: rapid induction, the least homodynamic instability, sufficient ventilation and oxygenation, Suppress of coughing, adequate maxillary and glottis relaxation for rapid placement of rigid bronchoscope and safe reversal with minimal postoperative complications.

Several methods of anesthesia are suggested include 1) IV sedation and use of muscle relaxants and maintenance by inhaling agents (2), induction and maintaining by inhaling agents with preserved spontaneous respirations (3), induction and maintaining by IV drugs with controlled or spontaneous ventilation (2-7) and pure intravenous method with jet ventilation (4).

When complete tracheal obstruction is probable and patient might not tolerate supine position, for example in giant parathyroid or para-tracheal tumors or foreign bodies that causes complete airway obstruction, it is better to use inhalation anesthesia with spontaneous ventilation to perform bronchoscopy (5) but now TIVA (total intravenous anesthesia) is the most common method for rigid bronchoscopy (2,5).

According to serious cardiovascular challenges during rigid bronchoscopy and probability of hyperventilation and hypoxia, light or deep anesthesia with halothane may cause arrhythmia so it’s better not to use halothane (5,7) and because of prolonged apnea periods, it’s better not to use N₂O too. Severe tracheal injury may occur because of bucking in rigid bronchoscopy so we should use muscle relaxants for adequate relaxation and controlled ventilation.

The other major problem is leak of inhaling anesthetic agents through eye piece of bronchoscope during extraction of foreign body .so according to inhibit environmental pollution, anesthetist would prefer total IV anesthesia. Since each of these two methods has advantages and disadvantages, in this paper we compare them for complications, the success and surgeon's satisfaction.

Materials and Methods

After Deputy of Research and Ethical committee approval, thirty patients 2 – 6 years old in ASA class I (American Society of Anesthesiologists) were included in this randomized study. They divided into two groups, inhalation anesthesia conducted on group I (n=15) and total IV method was used in group II (n=15).

Vital signs, indication of bronchoscopy and pulmonary symptoms before intervention were recorded and pulse-oximeter and monitoring was connected. Preoxygenation was done for 3 minutes in all cases. Induction by Fentanyl (2μg/kg) and Thiopental (3-5 mg/kg) and Succinylcholine (1-2 mg/kg) was done in group I. The patients received 1-2% halothane to maintain anesthesia after insertion of bronchoscope by Ear-Nose-Throat specialist. Succinylcholine was repeated if needed.

In group II Remifentanil (1 μg/kg), Propofol (2 mg/kg) and Succinylcholine     (1-2 mg/kg) were used for induction and anesthesia was maintained by Remifentanil (0.2-0.3μg/kg) and propofol (50-100 μg/kg/min). Atracurium was used (0.3 mg/kg bolus) for prolonged operations.

Heart rate, respiratory rate and arterial oxygen saturation were controlled after induction and also 5, 10, 20 ‚30 minutes after start of bronchoscopy and also in recovery room and at the time of entrance to the ward. Spo₂ more than 95%, 85<Spo₂2

Intra and postoperative complications such as coughing, bucking, laryngospasm, bronchospasm, pneumothorax, cyanosis, bradycardia and breath holding were recorded. Bronchoscopy success and surgeon satisfaction that was related to adequate muscular relaxation assessed at the end of the operation. The data was analyzed by chi-square, Fisher exact test and student T-test. P-value less than 0.05 considered significant.

Results

There wasn’t any significant difference in age, weight and gender distribution between two groups (Table 1). The most common indication for bronchoscopy was foreign body (70%) (Table 2) and the most common pulmonary sign before operation was expiratory wheezing (21%) (Table 3).

Table1: Demographic data of the patients in both groups.

Table2: The causes of the bronchoscopy in both groups N (%).

Table3: The symptoms of the patients prior to the operation N (%).

Mean arterial O₂ saturations (SpO₂) in both groups are shown in figure 1. Variation of SpO₂ from normal base was more significant in group I. This difference was especially more significant in 5, 10 and 30 minutes after induction and mild to moderate hypoxia was reported. Spo₂ changes in group II was in normal range. Mean Spo­₂ differences in 5, 10 and 30 minutes after induction were statistically different in two groups (P=0.005, P=0.033 and P=0.047, respectively).

Fig 1: Peripheral O2 saturation changes during bronchoscopy   (Mean)

Fig2: Respiratory rate changes during bron- choscopy (Mean).

Among 15 cases in group I, hypoxia wasn’t seen in 6 cases (40 %), 5 cases had mild hypoxia (33.3%) and 4 cases had severe hypoxia (26.6%) and among 15 cases in group II, hypoxia wasn’t seen in 13 cases (86.6%) and only two patient had mild hypoxia (13.3%). There was not any statistically significant difference in Spo₂ between two groups after bronchoscopy and in recovery and the time of entrance   to ward.

Respiratory rate was almost the same in both groups before and after bronchoscopy (P=1) and in recovery also there wasn’t any significant difference (P=0.064).

Heart ratewas increased after induction in group I and it reached to maximum after 20 minutes. HR was decreased after induction and in recovery in group II     (fig. 3) that it was significantly different between two groups (P-value was 0.027, 0.045 and 0.026 in 5, 10 and 20 minutes after induction, respectively).

Fig 3: Heart rate changes during broncho- scopy (Mean)

The complications were compared on table 4 and there are no significant differences. Outcome of the bronchoscopies were good in 10 cases (66.6%) of group I and in 8 cases (53.3%) of group II and totally, there wasn’t significant difference between success rate in two groups (P=0.637).

Surgeon satisfaction was significantly higher in the group II and poor satisfaction wasn’t reported in this group (Table 5).

Table4: The frequencies of the post-intubation complications. N (%).

Table 5: The rates of success of the operation and surgeons’ satisfaction rate. N (%)

Discussion

During rigid bronchoscopy the field of operation is out of reach of anesthetist while airway is manipulating during these operations, so a safe anesthesia method to maintain good oxygenation and stable homodynamic, with the least complications, is challenging for anesthetists.

Perrin et al (5) suggested IV anesthesia with propofol and Spontaneous assisted ventilation. They recommended muscular relaxation may be dangerous because of near complete tracheal stenosis and lack of tolerance supine position in giant paratracheal or mediastinal tumors in these patients.

Natalini et al (4) compared the effectiveness of two modalities of external ventilation during rigid bronchoscopy: intermittent negative pressure ventilation (INPV) and external high-frequency oscillation (EHFO). As compared to SAV, INPV in patients during rigid bronchoscopy reduces need to administration of opioids, shortens recovery time, prevents respiratory acidosis, excludes the need for manually assisted ventilation and affords optimal surgical conditions.

Hanowell et al (8) used controlled ventilation and muscle relaxants. Hypoxia was seen in 20%, re-intubation in 21%, need for extubation in recovery or ICU because of prolonged relaxation was reported in 47% of these patients.

Taha et al. conducted a study in 2005 to compare intubating conditions and cardiovascular changes following induction of anesthesia and tracheal intubation in patients receiving either lidocaine-remifentanil-propofol (group P) or lidocaine-remifentanil-thiopental (group T) prior to induction.  They concluded that Lidocaine-remifentanil-propofol is superior to lidocaine-remifentanil-thiopental for tracheal