Physiological perspectives of therapy in bronchial hyperreactivity

Purpose

This paper reviews the literature on the aetiology and therapy of bronchial hyperreactivity to describe the underlying pathophysiology, identify patients at risk and update knowledge on new and existing therapies.

Source

Information was obtained from monograms on New Drugs for Asthma, Respiratory Medicine: recent advances, Agents and Actions Supplements, Pulmonary Pharmacology, Anesth Analg, the European Journal of Respiration and a Medline literature search.

Principal findings

Reduced airway calibre, increased bronchial contractility, altered permeability of the bronchial mucosa, humoral and cellular mediators, and dysfunctional neural regulation are critical factors for bronchial hyperreactivity, a characteristic feature of hyperreactive airways which results in bronchoconstriction after exposure to varied stimuli. Preoperative anaesthetic considerations in these patients include FEV₁ and PEFR testing to assess the severity and for optimal control of the condition. Bronchospasm causing hypoxaemia is the major intraoperative problem anticipated in these patients. Current therapeutic management of bronchoconstriction focusses on the β₂ agonists, theophylline and steroids. Besides relaxing the airway smooth muscle these agents are all capable of altering bronchial inflammatory responses. Future developments of therapy are directed towards the inflammatory components of the disease.

Conclusion

This review has presented background information on physiological mechanisms of smooth muscle contractility, pathophysiological alterations of bronchial contractility and the pharmacological basis of therapy in bronchoconstrictive disease. Information is presented to enable the prompt arrest and reversal of airway constriction, and to maintain prophylactic treatment during the perioperative period. Intraopera’tive bronchospasm is managed by adequate oxygenation and reversal of bronchoconstriction     

Understanding and use of inhaler medication by asthmatics in specialty care in Trinidad: a study following development of Caribbean guidelines for asthma management and prevention

STUDY OBJECTIVES: Following the development of the Caribbean Guidelines for Asthma Care, we examined the utilization of inhaled medications in asthmatic patients in Trinidad, West Indies. SETTING: Chest Clinic, Ministry of Health, Trinidad. PARTICIPANTS: Physician-diagnosed asthmatic patients who attended the Chest Clinic between July 1998 and August 2000. MEASUREMENTS AND RESULTS: A consecutive sample of patients who were > 7 years of age (n = 402) was interviewed about compliance with, understanding of, and use of inhaler medication. The inhaler technique of these patients was directly observed. Inhaled steroid therapy was prescribed in 83% of patients but were prescribed the least in elderly patients (63%) and children (62%). Salbutamol was prescribed in 98% of patients, and ipratropium and sodium cromoglycate were selectively prescribed in elderly men and children, respectively. Only 33% of patients used the inhaler correctly, and children and the elderly were the least efficient in its use. The use of a spacer device was advised in 19% of patients, including only 6% of the elderly patients. Explanations for different inhaler therapies were given to 62% of patients, and 53% of patients could describe these reasons. The reported 40% noncompliance rate among patients in the sample was primarily a result of long waiting periods at the pharmacy (58%) and the personal cost incurred on purchasing the medication (52%). CONCLUSIONS: Educating patients, with a focus on children and the elderly, in inhaler techniques and reinforcing understanding of asthma medications can improve asthma management in Trinidad. Asthma caregivers in the Caribbean should ensure the appropriate dissemination of the guidelines and should outline strategies for their implementation.     

Pesticide regulation, utilization, and retailers' selling practices in Trinidad and Tobago, West Indies: current situation and needed changes.

OBJECTIVE: To explore pesticide regulation in Trinidad and Tobago, and to ascertain pesticide utilization and retailers' selling practices on Trinidad, which is the larger of twin islands that constitute the republic of Trinidad and Tobago. METHODS: Between February and June 2005, agrochemical retailers in Trinidad were surveyed about the most frequently sold pesticides and their knowledge and practices of pesticide sale. The Poisons and Toxic Chemicals Control Board of the Ministry of Health informed on legislature. RESULTS: Of 107 actively trading licensed pesticide outlets, 97 participated (91% response rate) in the survey. Currently only 2.9% (21) of 720 registered products from four chemical classes are frequently utilized. Paraquat, methomyl, and alpha-cypermethrin (respective trade names are Gramoxone, Lannate, and Fastac) from World Health Organization (WHO) Hazard Classes I and II, and glyphosate isopropylamine (Swiper, Class U) are the most frequently purchased pesticides. Pet shops constitute 39.2% (38) of retail shops selling pesticides. No regulations guide pesticide sale to agriculturists, and children may purchase them. Inadequate human and technical resources render legislative controls ineffective and disciplinary action against offenders is weak. Extensive governmental resources are employed in legislative procedures and product approval for the very low, 2.9% utilization rate, negatively impacting on monitoring pesticide sales. The Poisons Information Centre (PIC) does not liaise with the Poisons and Toxic Chemicals Control Board or provide educational interventions for the community. As a result of this survey, it was possible to develop the first database to include the chemical, brand, and colloquial names of pesticides used in Trinidad and Tobago; WHO classification of approved pesticides; manufacturers; packaging; and antidotes and their availability for use by the Board and health professionals in Trinidad. CONCLUSIONS: Urgent critical evaluation of legislation regarding pesticide imports and use, and partnership with the Rotterdam Convention are recommended for Trinidad and Tobago. A strengthened Poisons Information Centre can provide educational initiatives and information on early management of pesticide exposure.     

Catharanthus roseus flower extract has wound-healing activity in Sprague Dawley rats

Background  

Catharanthus roseus L (C. roseus) has been used to treat a wide assortment of diseases including diabetes. The objective of our study was to evaluate the antimicrobial and wound healing activity of the flower extract of Catharanthus in rats.     

Prevalence of chronic obstructive pulmonary disease among stable chronic disease subjects in primary care in Trinidad, West Indies

The prevalence of COPD in the Caribbean is uncertain. Spirometric indices were assessed at chronic disease clinics in 353 subjects (African, 66; East Indian, 198; 109 male), mean age 56.51 years (non-COPD) vs 59.30 years (COPD). 77 (21.8%) patients had COPD. 33.3% of COPD subjects had chronic cough vs 19.7% of subjects without COPD. A history of at least one chest infection was related to low FEV1 (P=0.005). In subjects presenting with vascular disease the FVC was reduced when compared to other subjects. Prevalence of COPD is 21.8%. A history of chest infections is related to decreased FEV1%.     

Caregivers' practices,knowledge and beliefs of antibiotics in paediatric upper respiratorytract infections in Trinidad and Tobago: a cross-sectional study

Background  

Antibiotic overuse and misuse for upper respiratory tract infections in children is widespread and fuelled by public attitudes and expectations. This study assessed knowledge, beliefs, and practices regarding antibiotic use for these paediatric infections among children's caregivers' in Trinidad and Tobago in the English speaking Caribbean.     

Risk factors for urinary tract calculi in Trinidad

OBJECTIVE: To identify risk factors for urinary tract stones in Trinidad and Tobago. METHODS: A consecutive series of patients presenting to institutions in Trinidad for the management of proven urinary tract calculi was interviewed by questionnaires designed to obtain data on age, gender, ethnicity, occupation, stone location, a family history of stone disease, a past history of certain medical diseases and a semiquantitative estimate of the magnesium intake in food, 'over the counter' drugs and drinking water. An equivalent number of patients attending the same institutions for follow-up and verified from hospital records as having a previous radiological diagnosis of urinary tract stones, as well as a group of asymptomatic members of the community working in the same area, underwent the same interview. Chi-square, anova and Kruskal-Wallis tests were used to examine differences between the groups. Multiple logistic regression analysis was used to determine persistence of the significance of these differences after controlling for confounding variables. RESULTS: Data sufficient for analysis were obtained for 122 previous and 102 prospective patients and 102 controls. The mean age of the patients was 32 years. The ratio of males to females was 0.9-1.8:1 for the affected groups, but significantly more males than females had calculi in the lower urinary tract (19%vs. 6%; P = 0.004). More patients (30%) than controls (7%) gave a positive family history of urinary tract stone disease (P < 0.001). Affected persons had a lower dietary magnesium intake (P = 0.003), which accounted for a significantly lower total magnesium intake (P = 0.02). Logistic regression analysis of the variables studied indicated that independent predictors of the disease were a positive family history (P = 0.001), total magnesium intake (P = 0.001) and age (P < 0.001). CONCLUSION: A low magnesium intake and a positive family history are highly predictive of urinary tract calculi in this population.     

Third generation cephalosporin use in a tertiary hospital in Port of Spain,Trinidad: need for an antibiotic policy

Background  

Tertiary care hospitals are a potential source for development and spread of bacterial resistance being in the loop to receive outpatients and referrals from community nursing homes and hospitals. The liberal use of third-generation cephalosporins (3GCs) in these hospitals has been associated with the emergence of extended-spectrum beta- lactamases (ESBLs) presenting concerns for bacterial resistance in therapeutics. We studied the 3GC utilization in a tertiary care teaching hospital, in warded patients (medical, surgical, gynaecology, orthopedic) prescribed these drugs.