EVIDENCE OF BRONCHOSPASM IN PATIENTS WITH HYPER-REACTIVE AIRWAY DISEASES ( HRAD ) FOLLOWING THIOPENTAL SODIUM INDUCTION OF ANESTHESIA

The objective of this study is to evaluate the evidence of bronchospasm in patients with hyperreactive airway disease (HRAD) following induction of anesthesia by thiopental sodium. The number of the patients participating in this study was 200. Patient`s physical status was class I and II according to American society of anesthesiologists (ASA). Age range was 17-55 years. Patients were subjected to different types of elective operations. The patients were assigned into two groups: first group was100 patients with normal airway considered as control group (group A) their age range was 17-55 years with a mean ±SD 30.3±9.95. The second group included 100 patients with asymptomatic hyper-reactive airway disease which was the case group (group B) their age range was 17 -50 years with a mean ±SD 30.60 ±8.29. From each patient a full history was taken and auscultation of the chest before induction of anesthesia was done, then oxygenation for 5 minutes with 100% oxygen was achieved without premedication. Anesthesia was induced by sleeping dose of intravenous (IV) thiopental and oxygenation was carried out by face mask, followed by auscultation of the chest immediately. Intubation was achieved with l mg /kg IV of Suxamethonium followed by assisted ventilation of the lung, and then re-auscultation of the chest was performed. The frequency of bronchospasm after thiopental induction in different types of hyper-reactive airway diseases of the case group was: 14 patients (58.3 %) from the total 24 case who they were a known case of bronchial asthma were developed bronchospasm while only 2 patients (2.9%) from the total 41 case who they have allergic bronchitis were developed bronchospasm, but no one with allergic rhinitis patients had bronchospasm. The differences among different types of hyper-reactive airway diseases of the case group (disease group) regarding the evidence of bronchospasm is of statistically significant with P-value less than 0.05.It is concluded from this study that thiopental is not contraindicated in all patients with HRAD especially those with allergic rhinitis & allergic bronchitis who they don`t have brochospasm while its contraindicated in bronchial asthma who they have bronchospasm preoperatively. Introduction ronchoconstriction may occur after tracheal intubation & occasionally may be severe enough to produce lifethreatening decrease in gas flow. Because induction is the period of highest risk for bronchospasm, it is important to select proper induction agents which minimize the bronchoconsrictor response to tracheal intubation & free from triggering chemical agents for bronchospasm . The effects of thiopental sodium on airway resistance remain controversial. Early studies indicated that thiopental release histamine & thus constrict the airways. However, thiopental may also inhibit vagal reflexes . And at higher B Evidence of bronchospasm in patients with hyper-reactive airway diseases following thiopental Nawfal A. Mubark Bas J Surg, March, 19, 2013 57 concentrations produce bronchodilatation. Intravenous (IV) induction agents are used in anesthesia practice to facilitate the patient's smooth transition to unconsciousness and intubation. The desired specific actions are an induction agent as a hypnotic and inhibition of upper airway reflexes. Generally the ideal induction agent should provide these actions without the side effects of respiratory &/or cardiac depression, nausea, vomiting & anaphylaxis. In addition, it should have a short duration of action and inexpensive. Unfortunately there is no individual induction agent has been shown to possess all of these characteristics, but the 2 agents that meet most of these criteria are thiopental and propofol . Thiopental is a primary IV induction agent for more than 50 years and considered is the standard by which newer induction agents are judged . It`s mechanism of action is thought to block the aminobutyric acid receptor on central nervous system (GABAA) & glycine receptors in addition which increased the channel opening time for chloride ion, the cause that increased the inhibitory effects. This results in potentiating of cell membrane chloride ion conductance and neuronal inhibition. Other inhibitory activity can be affect the central sodium & calcium ion. Thiopental is highly lipidsoluble, produce unconsciousness in fewer than 30 seconds, and has a short distribution half-life, with a termination of action within 4 to 15 minutes . Conversely, thiopental has an elimination half-life of 18 hours, and because of this, some practitioners believe it can result in a long-lasting sedative effect and a delay of emergence from anesthesia . Thiopental is also associated with some adverse effects, for example, thiopental can reduce the blood pressure, respiratory rate and cardiac output, with a compensatory increase in heart rate via an uninhibited baroreceptor reflex . Thiopental is also has been linked to causing an exacerbation of porphyria, bronchospasm, myoclonus, hiccup, and laryngospasm in people with asthma, and it can cause significant venous irritation when injected. In addition, thiopental has been shown to produce a hyperalgesia when given in subhypnotic doses, which can result in a decrease in analgesic efficacy for most opioids and analgesics . Despite these problems, thiopental remains the "gold standard" for induction agents because it is reliable and inexpensive. Aim of the study Hyper-reactive airway diseases are very common respiratory diseases in Basra, which contributes at high percent of population. The aim of this study is to identify the evidence & frequency of bronchospasm between HRAD patients after thiopental induction. Patients & Methods This is a case-control study included 200 patients undergoing different elective operations all patients were ASA physical status class I and II. The data have been collected from ALTaleeme Teaching Hospital, AL-Basrah General Hospital & AL-Fayha`a General Hospital during the period between April 2008-April 2010 .The patients were divided in to two groups: First group was 100 patients with normal airway as control group (group A). Their age range was 17-55 years with a mean ±SD 30.3±9.95.The second group was 100 patients they have had different types of asymptomatic HRAD (group B), their age range was 17 -50 years with a mean ±SD 30.60 ±8.29. For the determination of statistical significance among different variables, a descriptive statistics like mean and standard deviation together with analytic statistics like chi squared test, ANOVA test, T-test or Fischer exact test have been done when appropriate. P-value less than 0.05 was considered as significant. Evidence of bronchospasm in patients with hyper-reactive airway diseases following thiopental Nawfal A. Mubark Bas J Surg, March, 19, 2013 58 Results The total number of patients including in this study were 200 patients As shown in table I, 98 (49%) of them were females and 102 (51%) of them were males, 100 patients assigned as a case group which consist of 51 females and 49 males, while the other 100 patients who are the control group consist of 47 females and 53 males and reveals there were no significant difference between these two groups statistically. P value>0.05 is of no significance. Table II shows the mean age of all patients is 30.4 with ± SD of 9.14. For the case group the mean of age is 30.6 with ± SD of 8.29 and for the control group is 30.3 with ± SD of 9.95, this is also reveal no significant difference regarding the age difference among both groups (P value >0.05). Table III shows the different types of hyper-reactive airway diseases among the case group which reveals 24(6%) patients have bronchial asthma, 41(10.25%) have allergic bronchitis and 35(8.75%) have allergic rhinitis out of total 100 patients. Table IV shows the most important result which revealed the frequency distribution of bronchospasm among both groups; 16(18%) of case group had bronchospasm (positive) while 84(84%) of case group had normal vesicular breathing after thiopental induction (negative), while in the control group no one develop bronchospasm. The total data, about 18% have had bronchospasm, this percentage is of statistically significance between both groups and the P value less than O.05. In table V, the frequency distribution of bronchospasm among different sex for the case group, reveals 10 (24.4%) of males had bronchospasm while 6(11.8%) of females were suffered bronchospasm, this result has no statistical significance among both genders (P value >0.05). In table VI, the frequency of bronchospasm among different types of hyper-reactive airway diseases of the case group was 14(58.3%) of patients having a history of bronchial asthma had developed bronchospasm, 2 (2.9%) of patients with allergic bronchitis had bronchospasm while no one from those with allergic r initis has had a bronchospasm. This differences among different types of hyper-reactive airway diseases of the case group (disease group) is of statistically significant and the P-value is less than 0.05, specially highly significant for asthmatic patient in comparison with the other types of hyper-reactive airway diseases. Discussion This study is concerned with the evidence of bronchospasm in patients with hyperreactive airway disease after induction of anesthesia by thiopental sodium. It revealed that thiopental precipitated bronchospasm in 16 patients (18%) of case group that included 100 patients with hyper-reactive airway diseases while 84 patients (82%) of case group did not developed bronchospasm. In control group, no one developed bronchospasm. This study showed as well, that bronchospasm among different types of HRAD of the case group is about 14(58.3%) of patients with bronchial asthma. Two (2.9%) patients with allergic bronchitis developed bronchospasm while those patients with allergic rhinitis no one presented as bronchospasm and this differences among different types of 


Introduction
ronchoconstriction may occur after tracheal intubation & occasionally may be severe enough to produce lifethreatening decrease in gas flow.Because induction is the period of highest risk for bronchospasm, it is important to select proper induction agents which minimize the bronchoconsrictor response to tracheal intubation & free from triggering chemical agents for bronchospasm [1][2] .The effects of thiopental sodium on airway resistance remain controversial.Early studies indicated that thiopental release histamine & thus constrict the airways [3][4] .However, thiopental may also inhibit vagal reflexes 5 .And at higher B concentrations produce bronchodilatation 6 .Intravenous (IV) induction agents are used in anesthesia practice to facilitate the patient's smooth transition to unconsciousness and intubation.The desired specific actions are an induction agent as a hypnotic and inhibition of upper airway reflexes.Generally the ideal induction agent should provide these actions without the side effects of respiratory &/or cardiac depression, nausea, vomiting & anaphylaxis.In addition, it should have a short duration of action and inexpensive.Unfortunately there is no individual induction agent has been shown to possess all of these characteristics, but the 2 agents that meet most of these criteria are thiopental and propofol 7 .Thiopental is a primary IV induction agent for more than 50 years and considered is the standard by which newer induction agents are judged 8 .It`s mechanism of action is thought to block the aminobutyric acid receptor on central nervous system (GABAA) & glycine receptors in addition which increased the channel opening time for chloride ion, the cause that increased the inhibitory effects.This results in potentiating of cell membrane chloride ion conductance and neuronal inhibition.Other inhibitory activity can be affect the central sodium & calcium ion 9 .Thiopental is highly lipidsoluble, produce unconsciousness in fewer than 30 seconds, and has a short distribution half-life, with a termination of action within 4 to 15 minutes 10,11 .Conversely, thiopental has an elimination half-life of 18 hours, and because of this, some practitioners believe it can result in a long-lasting sedative effect and a delay of emergence from anesthesia 7 .Thiopental is also associated with some adverse effects, for example, thiopental can reduce the blood pressure, respiratory rate and cardiac output, with a compensatory increase in heart rate via an uninhibited baroreceptor reflex 10 .Thiopental is also has been linked to causing an exacerbation of porphyria, bronchospasm, myoclonus, hiccup, and laryngospasm in people with asthma, and it can cause significant venous irritation when injected 10,11 .In addition, thiopental has been shown to produce a hyperalgesia when given in subhypnotic doses, which can result in a decrease in analgesic efficacy for most opioids and analgesics 10 .Despite these problems, thiopental remains the "gold standard" for induction agents because it is reliable and inexpensive 12 .

Aim of the study
Hyper-reactive airway diseases are very common respiratory diseases in Basra, which contributes at high percent of population.The aim of this study is to identify the evidence & frequency of bronchospasm between HRAD patients after thiopental induction.

Patients & Methods
This is a case-control study included 200 patients undergoing different elective operations all patients were ASA physical status class I and II.The data have been collected from AL-Taleeme Teaching Hospital, AL-Basrah General Hospital & AL-Fayha`a General Hospital during the period between April 2008-April 2010 .The patients were divided in to two groups: First group was 100 patients with normal airway as control group (group A).Their age range was 17-55 years with a mean ±SD 30.3±9.95.The second group was 100 patients they have had different types of asymptomatic HRAD (group B), their age range was 17 -50 years with a mean ±SD 30.60 ±8.29.For the determination of statistical significance among different variables, a descriptive statistics like mean and standard deviation together with analytic statistics like chi squared test, ANOVA test, T-test or Fischer exact test have been done when appropriate.P-value less than 0.05 was considered as significant.

Results
The total number of patients including in this study were 200 patients As shown in table I, 98 (49%) of them were females and 102 (51%) of them were males, 100 patients assigned as a case group which consist of 51 females and 49 males, while the other 100 patients who are the control group consist of 47 females and 53 males and reveals there were no significant difference between these two groups statistically.P value>0.05 is of no significance.
Table II shows the mean age of all patients is 30.4 with ± SD of 9.14.For the case group the mean of age is 30.6 with ± SD of 8.29 and for the control group is 30.3 with ± SD of 9.95, this is also reveal no significant difference regarding the age difference among both groups (P value >0.05).Table III shows the different types of hyper-reactive airway diseases among the case group which reveals 24(6%) patients have bronchial asthma, 41(10.25%)have allergic bronchitis and 35(8.75%)have allergic rhinitis out of total 100 patients.Table IV shows the most important result which revealed the frequency distribution of bronchospasm among both groups; 16(18%) of case group had bronchospasm (positive) while 84(84%) of case group had normal vesicular breathing after thiopental induction (negative), while in the control group no one develop bronchospasm.The total data, about 18% have had bronchospasm, this percentage is of statistically significance between both groups and the P value less than O.05.In table V, the frequency distribution of bronchospasm among different sex for the case group, reveals 10 (24.4%) of males had bronchospasm while 6(11.8%) of females were suffered bronchospasm, this result has no statistical significance among both genders (P value >0.05).In table VI, the frequency of bronchospasm among different types of hyper-reactive airway diseases of the case group was 14(58.3%) of patients having a history of bronchial asthma had developed bronchospasm, 2 (2.9%) of patients with allergic bronchitis had bronchospasm while no one from those with allergic rhinitis has had a bronchospasm.This differences among different types of hyper-reactive airway diseases of the case group (disease group) is of statistically significant and the P-value is less than 0.05, specially highly significant for asthmatic patient in comparison with the other types of hyper-reactive airway diseases.

Discussion
This study is concerned with the evidence of bronchospasm in patients with hyperreactive airway disease after induction of anesthesia by thiopental sodium.It revealed that thiopental precipitated bronchospasm in 16 patients (18%) of case group that included 100 patients with hyper-reactive airway diseases while 84 patients (82%) of case group did not developed bronchospasm.In control group, no one developed bronchospasm.This study showed as well, that bronchospasm among different types of HRAD of the case group is about 14(58.3%) of patients with bronchial asthma.Two (2.9%) patients with allergic bronchitis developed bronchospasm while those patients with allergic rhinitis no one presented as bronchospasm and this differences among different types of hyper-reactive airway diseases of the case group is statistically significant specially among asthmatic patients in comparison with the other types of hyper-reactive airway diseases.These results are comparable with many articles and matching with many other studies in other locations as mentioned by Wylie, WD. and Churchill-Davidson who mentioned that the thiopental Sodium produced transient apnea and may require supportive manual ventilation, laryngeal reflexes remain intact, coughing, laryngeal spasm and mild bronchoconstriction can occur particularly in asthmatics patients 13 .This results are also comparable with other studies as mentioned by Clarke, R. S. J., Dundee, J. W. and Daw , who said that induction of anesthesia with thiopental, sometimes causes bronchospasm, although the mechanism by which thiopental induces bronchospasm may involve cholinergic stimulation, direct spastic effect and histamine release, the spastic effects of thiopental have not been comprehensively defined [14][15][16] .This work also revealed that the development of bronchospasm after thiopental induction is unrelated to sex and age between different groups and between the same group, which is statistically of no significant difference and this is comparable with that mentioned by Stephen Raftery.Bristol Royal Infirmary 17,18 .

Conclusion
There is a general Idea between anesthesiologist that thiopental sodium generally is contraindicated in all patients with HRAD while this study showed that HRAD its not only bronchial asthma but also include allergic rhinitis & allergic bronchitis, so thiopental is relatively contraindicated in patients with bronchial asthma &absolutely contraindicated in patient with brochospasm but neither in allergic bronchitis who do not have bronchospasm, nor in allergic rhinitis patients.

Recommendation
The anesthesiologist should distinguish & knows what is the meaning of HRAD in full details to enable him to choose the safe anesthetic induction agent for each disease belong to HRAD.