Background: In some patients chronic asthma results in irreversible airflow obstruction. High resolution computed tomography (HRCT) has been advocated for assessing the structural changes in the asthmatic lung and permits investigation of the relationships between airway wall thickening and clinical parameters in this condition. Methods: High resolution CT scanning was performed in 49 optimally controlled asthmatic patients and measurements of total airway and lumen diameter were made by two independent radiologists using electronic callipers. Wall area as % total airway cross sectional area (WA%) and wall thickness to airway diameter ratio (T/D) were calculated for all airways clearly visualised with a transverse diameter of more than 1.5 mm, with a mean value derived for each patient. Intra-and inter-observer variability was assessed for scope of agreement in a subgroup of patients. Measurements were related to optimum forced expiratory volume in 1 second (FEV 1 ), forced mid expiratory flow, carbon monoxide gas transfer, two scores of asthma severity, airway inflammation as assessed with induced sputum, and exhaled nitric oxide. Results: Neither observer produced a statistically significant difference between measurements performed on two occasions but there was a significant difference between observers (limits of agreement -2.6 to 6.8 for WA%, p<0.0001). However, mean WA% measured on two occasions differed by no more than 5.4% (limits of agreement -4.0 to 5.4; mean (SD) 0.7 (2.4)). Statistically significant positive associations were observed between both WA% and T/D ratio and asthma severity (r S =0.29 and 0.30, respectively, for ATS score), and an inverse association with gas transfer coefficient was observed (r S =-0.43 for WA% and r S =-0.41 for T/D). No association was identified with FEV 1 or airway inflammation. Conclusions: The airway wall is thickened in more severe asthma and is associated with gas transfer coefficient. This thickening does not relate directly to irreversible airflow obstruction as measured with FEV 1 .

Objective: This study aimed to determine the extent of agreement between central venous and arterial values for pH, bicarbonate, base excess, and lactate in a group of intensive care unit (ICU) patients. Methods: A prospective study of a convenience sample of patients deemed by their treating doctor to require blood gas analysis as part of their clinical care in ICU. It compared pH, bicarbonate, base excess and lactate on arterial and central venous samples taken within five minutes of each other. Data were analysed using bias (Bland-Altman) methods. Results: A total of 168 matched sample pairs from 110 patients were entered into the study. All variables showed close agreement. The mean difference between arterial and venous values of pH was 0.03 pH units, for bicarbonate 0.52 mmol/l, for lactate 0.08 mmol/l, and for base excess 0.19 mmol/l. All showed acceptably narrow 95% limits of agreement. Conclusion: Central venous pH, bicarbonate, base excess, and lactate values showed a high level of agreement with the respective arterial values, with narrow 95% limits of agreement. These results suggest that venous values may be an acceptable substitute for arterial measurement in this clinical setting.

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Objective: To describe the quality of postoperative documentation of vital signs and of medical and nursing review and to identify the patient and hospital factors associated with incomplete documentation. Design, setting and participants: Retrospective audit of medical records of 211 adult patients following major surgery in five Australian hospitals, August 2003 – July 2005. Main outcome measures: Proportion of patients with complete documentation of medical review (each day) and nursing review and vital signs (heart rate, blood pressure, respiratory rate, temperature and oxygen saturation) (each nursing shift), and the proportion of available opportunities for medical and nursing review where documentation was incomplete. Univariate and multivariate odds ratios for the association between incomplete documentation and hospital and patient factors. Results: During the first 3 postoperative ward days, 17% of medical records had complete documentation of vital signs and medical and nursing review. During the first 7 postoperative ward days, nursing review was undocumented for 5.6% of available shifts and medical review for 14.9% of available days. Respiratory rate was the most commonly undocumented observation (15.4% undocumented). Certain hospitals were significantly associated with incomplete documentation. Vital signs were more commonly undocumented in patients without epidural or patient‐controlled (PC) analgesia, during evening nursing shifts, and during successive postoperative ward days. Nursing review was more commonly undocumented in the evening and for patients without epidural or PC analgesia. Medical review was more commonly undocumented on weekends. Conclusion: Hospital and patient factors are associated with incomplete documentation of clinical review and vital signs after major surgery.