Peri-operative cardiac arrest due to suspected anaphylaxis as reported to the 7th National Audit Project of the Royal College of Anaesthetists

The 7th National Audit Project (NAP7) of the Royal College of Anaesthetists studied peri-operative cardiac arrest. Among 59 cases reported as possible anaphylaxis, 33 (56%) were judged to be so by the review panel with high or moderate confidence. Causes in excluded cases included: isolated severe hypotension; bronchospasm; and oesophageal intubation. Severe bronchospasm leading to cardiac arrest was uncommon, but notably in one case led to a reported flat capnograph. In the baseline survey, anaesthetists estimated anaphylaxis as the cause of 10% of cases of peri-operative cardiac arrests and to be among the four most common causes. In a year-long registry of peri-operative cardiac arrest, suspected anaphylaxis was the seventh most common cause accounting for 4% of reports. Initial management was most often with low-dose intravenous adrenaline, and this was without complications. Both the NAP7 baseline survey and case registry provided evidence of reluctance to starting chest compressions when systolic blood pressure had fallen to below 50 mmHg and occasionally even when it was unrecordable. All 33 patients were resuscitated successfully but one patient later died. The one death occurred in a relatively young patient in whom chest compressions were delayed. Overall, peri-operative anaphylaxis leading to cardiac arrest occurred with a similar frequency and patterns of presentation, location, initial rhythm and suspected triggers in NAP7 as in the 6th National Audit Project (NAP6). Outcomes in NAP7 were generally better than for equivalent cases in NAP6.

Right place, no trace: A case report of postintubation bronchospasm

Evidence suggests obesity correlates with airway hyperreactivity, which can result in severe bronchospasm. This report presents a 31-year-old female with a high body mass index who presented for a laparoscopic hysterectomy and bilateral salpingo-oophorectomy. She had no past medical or atopic history. After induction of anaesthesia and intubation, O2 saturation fell with no CO2 trace, breathing sounds or chest rise. Despite confirming endotracheal tube position by video laryngoscopy, the CO2 trace remained flat and mechanical ventilation was difficult with high airway pressures. Blood pressure was stable with no mucocutaneous signs of anaphylaxis. Administration of 100% O2, bronchodilators and steroids improved ventilation and oxygenation with a return of a CO2 trace. The operation was postponed. Prior to her subsequent surgery, the patient was premedicated with inhaled steroids and long-acting beta agonist with an uneventful induction and intubation. Giving a rising obese population, this case report aims to educate anaesthetists and anaesthetic practitioners as to the presentation, risk factors, mechanisms and management of uncommon, life-threatening postintubation bronchospasm.

Protective effect of Achyranthes aspera against compound 48/80, histamine and ovalbumin-induced allergic disorders in murine model

BACKGROUND

Achyranthes aspera L. (family Amaranthaceae) is a plant species valued in Ayurveda for the treatment of respiratory ailments. Scientific validation of its antiallergic potential was aimed.

METHODS AND RESULTS

Three extracts of A. aspera [aqueous (AaAq), hydroalcoholic (AaHA), ethanolic (AaEt)] were evaluated for their potency against C48/80-induced anaphylaxis in mice at 200 mg/kg BW oral dose. The effective dose of the most potent extract was determined through its effect on C48/80-induced anaphylaxis, and was further analyzed through its effect on mast cell degranulation, histamine-induced bronchospasm and ovalbumin (OVA)-induced asthma in a murine model. Among the three extracts, AaAq was found to be most potent at 200 mg/kg BW. AaAq 400 (400 mg/kg BW) was found to be the most effective dose in terms of inhibition of mortality and histamine level. AaAq 400 prevented the peritoneal and mesenteric mast cells from undergoing morphological changes due to degranulation induced by C48/80. Further, AaAq 400 delayed pre-convulsive time in histamine-induced bronchospasm. In the OVA-induced asthma model, AaAq 400 inhibited the level of inflammatory cell count in blood, bronchoalveolar lavage fluid and peritoneal fluid of mice. The Th2 cytokines (IL-4, IL-5, IL-13), TGF-β and OVA-specific IgE were also reduced as evaluated by ELISA. Also, significant reduction in IL-5 (an eosinophilia indicator) transcript abundance and lung inflammatory score was observed. AaAq was safe up to 4000 mg/kg BW.

CONCLUSIONS

Thus AaAq 400 possesses significant antiallergic potential and acts via attenuation of C48/80-induced anaphylaxis and inhibition of mast cell degranulation. It reduces pre-convulsive dyspnea in histamine-induced bronchospasm and Th2 cytokines in asthmatic mice.

[Clinical effect of Shenfu injection combined with glucocorticoid on patients with acute left heart failure complicated with bronchospasm]

OBJECTIVE

To investigate the clinical effect of Shenfu injection combined with glucocorticoid in the treatment of acute left heart failure complicated with bronchospasm.

METHODS

A prospective study was conducted.Ninety patients with acute left heart failure complicated with bronchospasm admitted to Huai'an Second People's Hospital from January 2021 to July 2022 were selected and divided into conventional treatment group, hormone therapy group and combined treatment group according to random number table method, with 30 cases in each group. All patients in the 3 groups received basic Western medicine treatment. On this basis, the conventional treatment group was given 0.25-0.50 g aminophylline injection plus 5% glucose injection or 0.9% sodium chloride injection (diabetes patients) 100 mL slow intravenous infusion, 1-2 times a day. In the hormone treatment group, 1 mg of budesonide suspension for inhalation was diluted to 2 mL by 0.9% sodium chloride injection, twice a day, and applied until 48 hours after the pulmonary wheezing disappeared. The combined treatment group was given glucocorticoid combined with Shenfu injection 80 mL plus 5% glucose injection or 0.9% sodium chloride injection (diabetes patients) 250 mL intravenously, once a day. All treated for 1 week. The general data, traditional Chinese medicine (TCM) syndrome score, TCM syndrone efficacy index, acute left heart failure efficacy, bronchospasm efficacy, systolic blood pressure (SBP), mean arterial pressure (MAP), serum N-terminal pro-brain natriuretic peptide (NT-proBNP) level and safety of the 3 groups were compared. The patients were followed up for 6 months, and the mortality and re-hospitalization rate of the 3 groups were recorded.

RESULTS

Among the 90 patients, a total of 83 patients completed the study, excluding the cases dropped due to death and other reasons. There were 29 cases in the combined treatment group, 25 cases in the hormone therapy group and 29 cases in the conventional treatment group. There were no significant differences in age, gender, course of disease, and previous history (history of diabetes, history of hypertension, history of hyperlipidemia) among the 3 groups. Therefore, they were comparable. The difference of TCM syndrome score before and after treatment, TCM syndrome efficacy index of combined treatment group and hormone therapy group were higher than those of conventional treatment group [difference of TCM syndrome score: 15.14±5.74, 13.24±5.75 vs. 10.62±5.87, TCM syndrome efficacy index: (67.84±14.31)%, (59.94±14.26)% vs. (48.92±16.74)%, all P < 0.05], and the difference of TCM syndrome score and TCM syndrome efficacy index of combined treatment group were higher than those of hormone treatment group (both P < 0.05). The total effective rate of acute left heart failure and bronchospasm in the combined treatment group was significantly higher than that in the conventional treatment group (total effective rate of acute left heart failure: 96.55% vs. 75.86%, total effective rate of bronchospasm: 93.10% vs. 65.52%, both P < 0.05). The difference of serum NT-proBNP before and after treatment in combination therapy group and hormone therapy group was significantly higher than that in conventional treatment group (ng/L: 7 922.86±5 220.31, 7 314.92±4 450.28 vs. 4 644.79±3 388.23, all P < 0.05), and the difference of serum NT-proBNP before and after treatment in the combined treatment group was significantly higher than that in the hormone treatment group (P < 0.05). There were no significant differences in SBP difference, MAP difference, mortality and re-hospitalization rate among the 3 groups. No adverse reactions occurred in the 3 groups during treatment.

CONCLUSIONS

Shenfu injection combined with glucocorticoid is effective in the treatment of patients with acute left heart failure complicated with bronchospasm. It is superior to glucocorticoid and aminophylline in relieving bronchospasm, reducing NT-proBNP level and improving total effective rate, and has good prognosis and safety.

Post-Acute COVID-19 Respiratory Symptoms in Patients With Asthma: An Electronic Health Records-Based Study

BACKGROUND

Post-viral respiratory symptoms are common among patients with asthma. Respiratory symptoms after acute COVID-19 are widely reported in the general population, but large-scale studies identifying symptom risk for patients with asthma are lacking.

OBJECTIVE

To identify and compare risk for post-acute COVID-19 respiratory symptoms in patients with and without asthma.

METHODS

This retrospective, observational cohort study included COVID-19-positive patients between March 4, 2020, and January 20, 2021, with up to 180 days of health care follow-up in a health care system in the Northeastern United States. Respiratory symptoms recorded in clinical notes from days 28 to 180 after COVID-19 diagnosis were extracted using natural language processing. Cohorts were stratified by hospitalization status during the acute COVID-19 period. Univariable and multivariable analyses were used to compare symptoms among patients with and without asthma adjusting for demographic and clinical confounders.

RESULTS

Among 31,084 eligible patients with COVID-19, 2863 (9.2%) had hospitalization during the acute COVID-19 period; 4049 (13.0%) had a history of asthma, accounting for 13.8% of hospitalized and 12.9% of nonhospitalized patients. In the post-acute COVID-19 period, patients with asthma had significantly higher risk of shortness of breath, cough, bronchospasm, and wheezing than patients without an asthma history. Incident respiratory symptoms of bronchospasm and wheezing were also higher in patients with asthma. Patients with asthma who had not been hospitalized during acute COVID-19 had additionally higher risk of cough, abnormal breathing, sputum changes, and a wider range of incident respiratory symptoms.

CONCLUSION

Patients with asthma may have an under-recognized burden of respiratory symptoms after COVID-19 warranting increased awareness and monitoring in this population.

Addition of nebulised lidocaine to prevent refractory bronchospasms in a patient receiving serial bronchoscopies

A patient in his 20s with a history of granulomatosis with polyangiitis required 15 bronchoscopies with dilations in 1 year due to bronchial fibrosis and secretions leading to worsening shortness of breath. During these bronchoscopies, the patient experienced increasingly severe bronchospasms refractory to conventional preventative and treatment methodologies leading to prolonged hypoxia, reintubations and ICU admissions. During his 8th to 15th bronchoscopies, nebulised lidocaine was added to the pretreatment regimen, which eliminated perioperative bronchospasms and allowed for the elimination of all other adjunctive preventative treatments. This case highlights the novel perioperative use of nebulised lidocaine, in combination with nebulised albuterol and intravenous hydrocortisone, to successfully prevent previously refractory bronchospasms in a patient undergoing a general anaesthetic.

RGS4 promotes allergen- and aspirin-associated airway hyperresponsiveness by inhibiting PGE2 biosynthesis

BACKGROUND

Allergens elicit host production of mediators acting on G-protein-coupled receptors to regulate airway tone. Among these is prostaglandin E2 (PGE2), which, in addition to its role as a bronchodilator, has anti-inflammatory actions. Some patients with asthma develop bronchospasm after the ingestion of aspirin and other nonsteroidal anti-inflammatory drugs, a disorder termed aspirin-exacerbated respiratory disease. This condition may result in part from abnormal dependence on the bronchoprotective actions of PGE2.

OBJECTIVE

We sought to understand the functions of regulator of G protein signaling 4 (RGS4), a cytoplasmic protein expressed in airway smooth muscle and bronchial epithelium that regulates the activity of G-protein-coupled receptors, in asthma.

METHODS

We examined RGS4 expression in human lung biopsies by immunohistochemistry. We assessed airways hyperresponsiveness (AHR) and lung inflammation in germline and airway smooth muscle-specific Rgs4^-/- mice and in mice treated with an RGS4 antagonist after challenge with Aspergillus fumigatus. We examined the role of RGS4 in nonsteroidal anti-inflammatory drug-associated bronchoconstriction by challenging aspirin-exacerbated respiratory disease-like (ptges1^-/-) mice with aspirin.

RESULTS

RGS4 expression in respiratory epithelium is increased in subjects with severe asthma. Allergen-induced AHR was unexpectedly diminished in Rgs4^-/- mice, a finding associated with increased airway PGE2 levels. RGS4 modulated allergen-induced PGE2 secretion in human bronchial epithelial cells and prostanoid-dependent bronchodilation. The RGS4 antagonist CCG203769 attenuated AHR induced by allergen or aspirin challenge of wild-type or ptges1^-/- mice, respectively, in association with increased airway PGE2 levels.

CONCLUSIONS

RGS4 may contribute to the development of AHR by reducing airway PGE2 biosynthesis in allergen- and aspirin-induced asthma.

Anaphylaxis to general anesthetics

The incidence of hypersensitivity reactions to anesthetics is estimated 1 in 13,000 anesthetics up to 1 in 3,180. The rate of mortality ranges between 3 and 9%. 90% of reactions appear at anesthesia induction. Cardiovascular collapse and bronchospasm are more frequent in IgE-dependent reactions. The leading causes are neuromuscular blocking agents (50-70% of cases). IgE-dependent reactions are predominant. Previous sensitization by other compounds containing quaternary ions is suspected. Cross-reactions are frequent. Latex allergy is the second cause, followed by antibiotics and beta-lactams in general. The incidence of anaphylaxis to vital dyes and chlorhexidine increases. Anaphylaxis to intravenous hypnotics, plasma substitutes, aprotinin, protamine and other drugs can occur. Any suspected hypersensitivity reaction during anesthesia must be extensively investigated to confirm the nature of the reaction, to identify the responsible drug, to study cross-reactivity in cases of anaphylaxis to a neuromuscular blocking agent and to provide recommendations for future anesthetic procedures. Tryptase assay at the time of the reaction has to be implemented by thorough investigations carried out weeks later: prick tests and intradermal tests, quantification of specific IgE to compounds containing quaternary ammonium ions, histamine release test or cytometric analysis of basophile activation.

Uterine contractions: an unusual side effect of venom immunotherapy

Venom immunotherapy (VIT) is an efficient treatment modality for preventing further sting-induced anaphylactic reactions in patients with Hymenoptera venom allergy. The main side effects of VIT include local and systemic allergic reactions with a variable risk of up to 46%. We report the case of a woman who experienced rapid-onset hypocalcemia and regular uterine contractions on 3 occasions within 30 minutes of receiving Apis mellifera VIT. To the best of our knowledge, this is the first report of uterine contractions as a side effect of VIT. The importance of this event is clear, as VIT has now been approved for pregnant women. We provide recommendations to physicians using this modality.

Lettuce-induced anaphylaxis. Identification of the allergen involved

BACKGROUND

Only 2 allergenic proteins have been described in lettuce allergy: a 16-kDa protein (putative profilin) and a lipid transfer protein (LTP) named Lac s 1.

OBJECTIVE

Our aim was to identify the allergens involved in the anaphylactic reactions of 2 patients who had eaten lettuce.

METHODS

The study was performed by Ig (immunoglobulin)-E immunodetection and immunodetection-inhibition assays.

RESULTS

Both patients' sera showed specific IgE binding to a single protein from the crude lettuce extract (apparent molecular weight of 14 kDa). To characterize the allergen detected, the lettuce extract underwent proteolytic digestion and heat treatment and was highly resistant to both. The patients' sera also recognized the major peach allergen Pru p 3 by immunodetection. When the lettuce allergen was incubated with both Pru p 3 from peach peel and recombinant Pru p 3, the immunodetection-inhibition assay indicated that patients were sensitized to the lettuce LTP Lac s 1.

CONCLUSIONS

The allergen involved in the lettuce-induced anaphylaxis of our patients was the LTP Lac s 1.

The value of care algorithms

The use of protocols or care algorithms in medical facilities has increased in the managed care environment. The definition and application of care algorithms, with a particular focus on the treatment of acute bronchospasm, are explored in this review. The benefits and goals of using protocols, especially in the treatment of asthma, to standardize patient care based on clinical guidelines and evidence-based medicine are explained. Ideally, evidence-based protocols should translate research findings into best medical practices that would serve to better educate patients and their medical providers who are administering these protocols. Protocols should include evaluation components that can monitor, through some mechanism of quality assurance, the success and failure of the instrument so that modifications can be made as necessary. The development and design of an asthma care algorithm can be accomplished by using a four-phase approach: phase 1, identifying demographics, outcomes, and measurement tools; phase 2, reviewing, negotiating, and standardizing best practice; phase 3, testing and implementing the instrument and collecting data; and phase 4, analyzing the data and identifying areas of improvement and future research. The experiences of one medical institution that implemented an asthma care algorithm in the treatment of pediatric asthma are described. Their care algorithms served as tools for decision makers to provide optimal asthma treatment in children. In addition, the studies that used the asthma care algorithm to determine the efficacy and safety of ipratropium bromide and levalbuterol in children with asthma are described.

[The consequence of epinephrine (adrenaline) overdose]

Epinephrine is an adrenergic agonist used to treat bronchospasm, anaphylactic reactions, bradycardia, cardiac arrest, and hypotension. Its toxicity is usually caused by iatrogenic errors. In overdose there is a typical rapid onset of agitation, hypertension, tachycardia, and dysrhythmias. This review article focuses on the causes of overdose, signs and symptoms, treatment and expected course, and prognosis of this iatrogenic pathology.

[Two tracheal tubes inserted for endotracheal tube replacement in a patient with severe obstructive sleep apnea: a case report]

A 34-year-old obese, small-jawed and short-necked woman, had severe obstructive sleep apnea syndrome (OSAS) with bronchial asthma. A surgical removal of a lingual tumor using a laser knife was scheduled under general anesthesia with sevoflurane. A small diameter tracheal tube for laser surgery (internal diameter (ID) of 5.5 mm) was used. The tube was inserted using bronchofiberscopy under spontaneous respiration. Extubation was designed to be performed when the patient resumed adequate spontaneous respiration and was awake. However, her ventilation deteriorated postoperatively as spontaneous breathing continued (PaO2 98 mmHg, PaCO2 88 mmHg at FIO2 1.0). This seemed to have been induced by worsened patient-ventilator synchrony and increased airway resistance due to the use of a small diameter tube. We decided to replace the tube with the one with larger diameter. An ID 7.5 mm tube was inserted with the use of fiberscope through the opening of the vocal cord while the tube for laser surgery was left in space. After confirming that the two tubes were inserted securely, the tube for laser surgery was withdrawn. The patient's ventilation improved significantly afterwards and the extubation was performed successfully. Our method for replacing a tracheal tube seemed to be effective and safe.

Urinary trypsin inhibitor improves peripheral microcirculation and bronchospasm associated with systemic anaphylaxis in rabbits in vivo

Using intravital microscopy of the rabbit ear for quantitative studies of microvascular dynamics, we examined the impact of urinary trypsin inhibitor (UTI), a proteolytic enzyme inhibitor, on microvascular changes during immune complex-mediated anaphylaxis. A total of 50 rabbits, previously sensitized with horse serum, were anesthetized and mechanically ventilated with pentobarbital and isoflurane for the intravital microscopy. Rabbits were then challenged with intravenous injection of horse serum to induce systemic anaphylaxis. One minute after the challenge, each rabbit was randomly assigned to receive saline (group C), 50,000 units x kg(-1) of UTI (group U1), or 150,000 units x kg(-1) (group U2). There were no statistical differences between hemodynamic variables, including heart rate (HR), mean arterial pressure (MAP), and central venous pressure (CVP), among the survivors in each treatment group. Peak inspiratory pressure rose in all three groups but at a much higher rate in group C (P < 0.05). In contrast with the moderate effects of UTI on the above parameters, microscopic evaluation revealed a substantial difference among treatment groups: upon the initiation of anaphylaxis, the arteriole started to reduce in diameter, but UTI prevented vasoconstriction in the arteriole in a dose-dependent manner. Similar results were observed with blood flow velocity. Because flow rate was calculated as the product of blood flow velocity and vascular cross-sectional area proportional to the square of the vessel diameter, these results indicate that UTI preserves microvascular flow rate during anaphylaxis. Rabbit ear microcirculation is highly preserved in the UTI-treated groups during systemic anaphylactic shock.

Significant improvement in symptoms, skin test, and specific bronchial reactivity after 6 months of treatment with a depigmented, polymerized extract of Dermatophagoides pteronyssinus and D. farinae

BACKGROUND

The efficacy of allergen immunotherapy using depigmented and polymerized extracts has been previously shown for Olea europaea, Phleum pratense, and Parietaria judaica. The objective of this study was to evaluate the efficacy after 3 and 6 months of treatment of a depigmented, polymerized extract of a mixture of Dermatophagoides pteronyssinus and D. farinae.

METHODS

A group of 22 patients suffering from asthma and monosensitized to mites was treated with the mixture of modified allergen extract. A group of 11 mite-sensitive, asthmatic patients receiving only pharmacological treatment was used as control. The study was open, parallel, controlled, and random-allocated. Objective and subjective criteria, such as changes in D. pteronyssinus-specific bronchial hyperreactivity, visual scale, and medication/symptom scores were used to evaluate efficacy. Each patient received a built-up phase of 6 injections in 5 weeks, followed by 5 injections of the maintenance dose, which consisted of 42.5 micrograms of depigmented, polymerized extract of D. pteronyssinus and 32.5 of D. farinae. The Friedman test was used to compare the results of the specific bronchial challenges at baseline and after 3 and 6 months of treatment.

RESULTS

A significant difference in the amount of native extract of D. pteronyssinus needed to produce a drop of 20% in the FEV1 (p = 0.0029) in the immunotherapy-treated group was found. In this group, the median allergen potency needed at baseline was 0.6 HEP (35 micrograms) vs. 3.96 HEP (232 micrograms) at the end of the study, whereas no difference (median 0.6 vs. 0.57 HEP) was found in the control group. At the end of the study, 10 patients in the immunotherapy treated group vs. 1 in the control group needed more than twice the amount of allergen than at baseline to experience a 20% drop in FEV1 (p = 0.03). Symptom and medication scores and visual scale evaluation did also show a significant improvement after 3 and 6 months of treatment only in active group. A significant decrease in skin test reactivity was also detected in the active group after 6 months, which needed a median of 3 times more allergen to elicit the same reaction as histamine (10 HEP) (p = 0.028), whereas no changes were found in control group. No serious side effects were registered.

CONCLUSIONS

Depigmented polymerized extracts of D. pteronyssinus and D. farinae are safe and effective in the treatment of mite allergic asthmatic patients, and provide clinical benefit in the shock organ after 6 months of treatment. Skin test reactivity, symptom and medication scores were also improved. Depigmented polymerized extracts of D. pteronyssinus and D. farinae induce clinical protection against a native extract as verified by specific bronchial challenges.

Self-reported symptoms and exercise-induced asthma in the elite athlete

PURPOSE

The purpose of this study was to compare self-reported symptoms for exercise-induced asthma (EIA) to postexercise challenge pulmonary function test results in elite athletes.

METHODS

Elite athletes (N = 158; 83 men and 75 women; age: 22 +/- 4.4 yr) performed pre- and post-exercise spirometry and were grouped according to postexercise pulmonary function decrements (PFT-positive, PFT-borderline, and PFT-normal for EIA). Before the sport/environment specific exercise challenge, subjects completed an EIA symptoms-specific questionnaire.

RESULTS

Resting FEV1 values were above predicted values (114--121%) and not different between groups. Twenty-six percent of the study population demonstrated >10% postexercise drop in FEV1 and 29% reported two or more symptoms. However, the proportion of PFT-positive and PFT-normal athletes reporting two or more symptoms was not different (39% vs. 41%). Postrace cough was the most reported symptom, reported significantly more frequently for PFT-positive athletes (P < 0.05). Sensitivity/specificity analysis demonstrated a lack of effectiveness of self-reported symptoms to identify PFT-positive or exclude PFT-normal athletes. Postexercise lower limit reference ranges (MN-2SDs) were determined from normal athletes for FEV1, FEF25--75% and PEF to be -7%, -12.5%, and -18%, respectively.

CONCLUSION

Although questionnaires provide reasonable estimates of EIA prevalence among elite cold-weather athletes, the use of self-reported symptoms for EIA diagnosis in this population will likely yield high frequencies of both false positive and false negative results. Diagnosis should include spirometry using an exercise/environment specific challenge in combination with the athlete's history of asthma symptoms.

Effect of nebulized albuterol on circulating leukocyte counts in normal subjects

Nebulized beta 2-receptor agonists may cause neutrophil demargination and result in misleading total circulating leukocyte counts (WBCs) in patients with acute bronchospasm. Varying underlying adrenergic stimulation in these patients also makes interpretation of these data difficult. This study examined the direct effect of these agents on the measured WBCs of healthy adults without evidence of bronchospasm or illness. A prospective, blinded, randomized study of 30 healthy volunteers (aged 18-50 years) was performed in a controlled environment. Subjects were excluded if they were pregnant, had a known underlying medical disorder or have had a prior reaction to albuterol or similar medications. Participants in the study were given either a nebulized albuterol treatment or nebulized normal saline (control group). Leukocyte counts were then obtained before and after treatments. Paired data were analysed using a one-tailed t-test while considering an increase of 40% in WBCs to be significant, P = 0.05, and beta = 0.10. Mean leukocyte counts were 5.9 (+/- 1.2) before treatment as compared to 6.0 (+/- 1.3) after albuterol nebulization. Using the coefficient of variance of WBCs in normal humans as c. 50% (6000 +/- 3000 cells mm-1) we were unable to demonstrate a significant difference in variation in post-nebulized leukocyte counts between the control group and the nebulized albuterol group. While there is concern that the treatment of patients experiencing acute bronchospasm with beta 2 agonists may result in factitious elevations in peripheral leukocyte counts, were found no direct effect of these agents on measured counts in normal subjects.

Influence of nasal fontanel receptors on the regulation of tracheobronchal vagal tone

AIM

To test the hypothesis according that the receptors located in the nasal fontanels influence the regulation of the tracheobronchial tree vagus tone.

METHODS

Changes in respiratory parameters (forced expiratory volume in the first second- FEV1 and total resistance- Rt) occurring consequentially to light mechanical nasal stimulation were determined in healthy volunteer, non-smokers using spirometric and body plethysmographic measurements. The parameters were measured before and at 15 and 60 min after mechanical stimulation with cotton pledge.

RESULTS

In subjects in whom the middle nasal meatus was stimulated by a cotton pledge soaked in saline, FEV1 decreased (p=0.01) and Rt increased (p=0.03). In subjects in whom the middle nasal meatus was stimulated by a cotton pledge soaked in 5% cocaine solution, no change was observed. In the control group of subjects, in whom the inferior nasal concha was stimulated by a cotton pledge soaked in saline, only a statistically significant decrease for FEV1 (p=0.04) was found.

CONCLUSION

There is a reflex communication between the nasal fontanel receptors and lungs, which is regulating the tracheobronchial vagal tone and resistance in lung airways. Further studies of this important physiologic relation are needed.

Diagnosis of Pfiesteria-human illness syndrome

The first case reports of human illness caused by exposure to Pfiesteria piscicida toxin(s) acquired outside of a laboratory are reported. Though Pfiesteria, a toxin-forming dinoflagellate, is responsible for killing billions of fish in estuaries in North Carolina, its role in human illness has remained controversial, in part due to lack of identification of the toxin. A recent fish kill in the rivers of the lower Eastern Shore has permitted careful investigation and identification of a distinct clinical syndrome resulting from exposure to the Pfiesteria toxin--Pfiesteria human illness syndrome (PHIS). Patients have memory losses, cognitive impairments, headaches, skin rashes, abdominal pain, secretory diarrhea, conjunctival irritation, and bronchospasm. Not all patients have all elements of the syndrome.

[The clinical scoring system for predicting the risk of intraoperative and postoperative bronchospasm]

Patients with bronchial asthma (BA) are usually considered to have a high risk of developing bronchospasm (BS) during anesthesia. Our clinical scoring system for preoperative assessment in BA patients was used to predict the risk of intraoperative and postoperative BS. Thirty two patients with a history of BA were studied retrospectively, assessing preoperatively with our clinical scoring system; Bronchial Asthma Risk Index Score (BARIS). BARIS was composed of a total of ten items. Five of them were scored before inhalation of bronchodilators and remaining five items were scored after the inhalation. Each item was scored by 0, 1, or 2. Four of 32 patients developed BS peroperatively (BS group). Twenty eight patients developed no BS peroperatively (control group). The total scores of pre-inhalation five items were 4.8 +/- 1.9 in BS group and 2.0 +/- 1.3 in control group, and the total scores of post-inhalation five items were 4.0 +/- 1.4 in BS group and 1.3 +/- 1.0 in control group. There were significant differences between the two groups (P < 0.05, Mann-Whitney U-test). We conclude that BARIS is useful in evaluating the risk of peroperative bronchospasm in patients with a history of bronchial asthma.

Hypoxaemia and hypotension after intravenous codeine phosphate

This report describes a case of accidental intravenous administration of codeine phosphate (1 mg.kg-1) to a previously healthy five-year-old boy, who was undergoing strabismus surgery. Hypoxaemia (SpO2 85% with FIO2 of 1) and hypotension (systolic BP 65 mmHg) resulted, which responded to resuscitation with lactated Ringers' (20 ml.kg-1) and phenylephrine (2 micrograms.kg-1). The degree of hypoxaemia observed in this case was severe, but was not associated with clinical evidence of bronchospasm. Possible mechanisms for this reaction might have included direct myocardial depression and histamine release. This case adds further support to the recommendation that codeine phosphate should never be administered intravenously.

The role of calcium antagonists in bronchial reactivity

Calcium (Ca) ions play an important pathophysiologic role in allergic reactions. Thus, mediator release from mast cells, synthesis of some newly formed chemical mediators, airway smooth muscle contraction, and nerve-impulse conduction are all dependent on the availability and flux of Ca ions. It is likely, therefore, that Ca antagonists would modify allergic bronchoconstriction. In vitro, Ca antagonists have been demonstrated to inhibit mediator release (histamine, slow-reacting substance of anaphylaxis, and platelet-activating factor) from mast cells, passively sensitized human lung fragments, and leukocytes. Ca antagonists have also been found to inhibit synthesis of leukotrienes in rat lungs and cyclooxygenase products in sheep, possibly by inactivating phospholipase A2 and/or 5-lipoxygenase. In addition, nifedipine, verapamil, and gallopamil have demonstrated inhibition of airway smooth muscle contractions to histamine, carbachol, and antigen in various species. In vivo effects of Ca antagonists are variable, depending on the species, experimental design, the stimulus or the agonist, and the Ca antagonist used. Animal studies have demonstrated the inhibition of histamine, methacholine, citric acid, and prostaglandin F2 alpha-induced bronchoconstriction in guinea pigs and dogs by intravenous nifedipine. In contrast, verapamil inhibited antigen-induced bronchoconstriction in allergic sheep without any effect on histamine- and carbachol-induced responses. Ca antagonists (nifedipine and verapamil) have been of limited value in human subjects and generally have no significant bronchodilating activity. Both nifedipine and verapamil prevent the exercise-induced asthma and partly attenuate the histamine and methacholine-induced bronchoconstriction. Oral nifedipine is generally more effective than oral verapamil against acute antigen-induced bronchoconstriction; however, this efficacy may be limited by systemic side effects. Inhaled Ca antagonists may be more effective and free of systemic side effects, as demonstrated by greater efficacy of inhaled verapamil. A new Ca antagonist, gallopamil (a methoxy derivative of verapamil), is being investigated as an aerosol, and preliminary studies in animals and humans have found it fourfold to seventeenfold more potent than verapamil. In sheep, gallopamil has been found to attenuate histamine, carbachol, and platelet-activating factor-induced bronchoconstriction, as well as to inhibit early and late-phase allergic airway responses. Studies in human subjects have also demonstrated the inhibition of antigen-induced bronchoconstriction by inhaled gallopamil, with efficacy comparable or better than cromolyn sodium.(ABSTRACT TRUNCATED AT 400 WORDS)

Regional deposition in human lung of 2.5 microM particles

Regional deposition in the lung of 111In-labelled Teflon particles with an aerodynamic diameter of 2.5 micron was studied in eight healthy nonsmokers. The particles were inhaled at 0.5 l/sec with maximally deep breaths. Bronchoconstriction was induced by inhalation of a methacholine bromide aerosol, for one exposure series before (provocation experiment) and for one exposure series after (control experiment) inhalation of the Teflon particles. Airway resistance (Raw) was measured with a whole-body plethysmograph before and after the induction of bronchoconstriction and increased on an average by a factor of 3-4. The total lung deposition, in percent of the inhaled radioactivity, was 83 +/- 6% (mean +/- SD) for the control experiment and 84 +/- 5% for the provocation experiment. Alveolar deposition, estimated as the percentage retention of lung deposition after 24 hrs (Ret24), was significantly lower in the provocation experiment than in the control experiment, 42 +/- 10% and 77 +/- 12%, respectively. Ret24 varied greatly among the subjects in the control experiment; for example, individual tracheobronchial deposition varied by a factor of 5. Ret24 was not related to FEV1, FVC or Raw. The Ret24 values in the two exposure series correlated significantly indicating an individual factor. Retention at 3 and 24 hrs correlated strongly, r = 0.94. This implies that radionuclides with half-lives of a few hours, e.g., 99mTc, can be used in studies of regional lung deposition when mucociliary transport system has been stimulated.

Allergen challenge of lung tissue from asthmatics elicits bronchial contraction that correlates with the release of leukotrienes C4, D4, and E4

The leukotrienes C4, D4, and E4, previously referred to as slow reacting substance of anaphylaxis, elicited long-lasting contractions of bronchi isolated from two birch pollen-sensitive asthmatics. The leukotrienes were 1,000 times more potent on a molar basis than was histamine or prostaglandin F2 alpha. Moreover, allergen released leukotrienes C4, D4, and E4 from the lung tissue of the asthmatics in amounts that appeared to correlate well to the anaphylactic bronchial contraction. Irrespectively of whether the lung was stimulated with specific allergen, the ionophore A23187 or 14C-labeled arachidonic acid, 15-hydroxyicosatetraenoic acid, and other lipoxygenase-derived monohydroxy acids were the major metabolites of arachidonic acid in the lung, and thromboxane A2 and prostaglandin I2 were the predominant cyclooxygenase products identified. However, cyclooxygenase inhibition with indomethacin had no effect on the contraction response to antigen in the bronchi, whereas, in the presence of U-60257, an inhibitor of leukotriene biosynthesis, the allergen neither released leukotrienes from the lung nor caused bronchial contraction. These findings indicate that leukotrienes C4, D4, and E4 are major mediators of allergic bronchoconstriction in man.