Incidence of early diaphragmatic dysfunction after lung transplantation: results of a prospective observational study

BACKGROUND

Diaphragmatic dysfunction is common after cardiothoracic surgery, but few studies report its incidence and consequences after lung transplantation. We aimed to estimate the incidence of diaphragmatic dysfunction using ultrasound in lung transplant patients up to 3 months postoperatively and evaluated the impact on clinical outcomes.

METHODS

This was a single-center prospective observational cohort study of 27 lung transplant recipients using diaphragmatic ultrasound preoperatively, at 1 day, 1 week, 1 month, and 3 months postoperatively. Diaphragmatic dysfunction was defined as excursion < 10 mm in men and < 9 mm in women during quiet breathing. Clinical outcomes measured included duration of mechanical ventilation, length of stay (LOS) in Intensive Care (ICU), and hospital LOS.

RESULTS

Sixty-two percentage of recipients experienced new, postoperative diaphragmatic dysfunction, but the prevalence fell to 22% at 3 months. No differences in clinical outcomes were found between those with diaphragmatic dysfunction compared to those without. Patients who experienced diaphragmatic dysfunction at 1 day postoperatively were younger and had a lower BMI than those who did not.

CONCLUSIONS

Diaphragmatic dysfunction is common after lung transplant, improves significantly within 3 months, and did not impact negatively on duration of mechanical ventilation, LOS in ICU or hospital, or discharge destination.

Commencing Out-of-Bed Rehabilitation in Critical Care-What Influences Clinical Decision-Making?

OBJECTIVES

To develop a decision tree that objectively identifies the most discriminative variables in the decision to provide out-of-bed rehabilitation, measure the effect of this decision and to identify the factors that intensive care unit (ICU) practitioners think most influential in that clinical decision.

DESIGN

A prospective 3-part study: (1) consensus identification of influential factors in mobilization via survey; (2) development of an early rehabilitation decision tree; (3) measurement of practitioner mobilization decision-making. Treating practitioners of patients expected to stay >96 hours were asked if they would provide out-of-bed rehabilitation and rank factors that influenced this decision from an a priori defined list developed from a literature review and expert consultation.

SETTING

Four tertiary metropolitan ICUs.

PARTICIPANTS

Practitioners (ICU medical, nursing, and physiotherapy staff) (N=507).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

A decision tree was constructed using binary recursive partitioning to determine the factor that best classified patients suitable for out-of-bed rehabilitation. Descriptive statistics were used to describe practitioner and patient samples as well as patient adverse events associated with out-of-bed rehabilitation and the factors prioritized by ICU practitioners.

RESULTS

There were 1520 practitioner decisions representing 472 individual patient decisions. Practitioners classified patients suitable for out-of-bed rehabilitation on 149 occasions and not suitable on 323 occasions. Decision tree analysis showed the presence of an endotracheal tube (ETT) and sedation state were the only discriminative variables that predicted patient suitability for rehabilitation. In contrast, medical staff and nurses reported that ventilator status was the most influential factor in their decision not to provide rehabilitation while physiotherapists ranked sedation most highly. The presence of muscle weakness did not inform the decision to provide rehabilitation.

CONCLUSION

These results confirm previous observational reports that the presence of an ETT remains a major obstacle to the provision of rehabilitation for critically ill patients. Despite rehabilitation being effective for improving muscle strength, the presence of muscle weakness did not influence the decision to provide rehabilitation.

Detection and speciation of Cryptosporidium spp. in environmental water samples by immunomagnetic separation, PCR and endonuclease restriction

Current methods for the detection of Cryptosporidium oocysts in water samples are both time-consuming and subject to variation in sensitivity. A genus-specific PCR assay was designed for the specific amplification of a 552-bp region of the 18S rRNA gene. Postamplification endonuclease restriction generated unique digest patterns that enabled differentiation between the three species, C. muris, C. baileyi and C. parvum, the major human pathogen. Theoretical restriction profiles for other Cryptosporidium species were also predicted. The assay routinely detected 10 oocysts in 10-ml purified oocyst preparations, but sensitivity was found to be 10(3)-10(4) -fold lower in environmental water samples. The use of Chelex resin and an immunomagnetic separation procedure overcame this inhibition. This provided detection levels of 10(1)-10(3) oocysts, depending on water turbidity. Rapid and sensitive pathogen detection methods are essential for the water industry. The results of this study demonstrate that PCR has the potential to improve current detection capabilities greatly by differentiating the major human pathogens from non-pathogenic species. This will greatly facilitate a closer examination of the epidemiology of this important pathogen.

Effects of combination therapy with an angiotensin converting enzyme inhibitor and thiazide diuretic on insulin action in essential hypertension

OBJECTIVE

To determine whether combination of an angiotensin converting enzyme inhibitor with a high dose of thiazide diuretic avoids adverse metabolic consequences of thiazide diuretics.

DESIGN

Double-blind randomized crossover study of two 12-week treatment periods with captopril (up to 100 mg/day) either alone or in combination with 5 mg bendrofluazide given after a 6-week placebo run-in period. Treatment periods were separated by a 6-week placebo washout period.

SETTING

Outpatient clinics in greater Belfast.

PATIENTS

Fifteen white non-diabetic essential hypertensives (seven male) aged < 65 years recruited from general practices in greater Belfast.

MAIN OUTCOME MEASURES

Systolic and diastolic blood pressures and peripheral and hepatic insulin action.

RESULTS

Two patients failed to complete the study. Blood pressure was lowered (139/89+/-18/7 mmHg combination versus 160/97+/-21/7 mmHg captopril; P < 0.001). Fasting insulin level was raised (7.9+/-3.6 mU/l combination versus 6.2+/-3.2 mU/l baseline; P < 0.001). There were no differences between treatments for glucose, urate, cholesterol and triglyceride levels. Serum potassium level was lowered (3.8+/-0.4 mmol/l combination versus 4.2+/-0.4 mmol/l captopril, P < 0.05). Postabsorptive endogenous glucose production was raised (10.8+/-1.7 micromol/kg per min combination versus 10.0+/-1.5 micromol/kg per min captopril; P < 0.01) and was greater than baseline (9.7+/-2.1 micromol/kg per min, P < 0.05). Suppression of glucose production by insulin was similar with both treatments. Exogenous glucose infusion rates required to maintain euglycaemia did not differ (32.4+/-7.6 micromol/kg per min captopril, 32.7+/-6.2 micromol/kg per min combination, 31.5+/-7.2 micromol/kg per min baseline).

CONCLUSIONS

Combination therapy increased glucose production (compared with captopril alone), indicating hepatic insulin resistance. It cannot be assumed that combined preparations with angiotensin converting enzyme inhibitors will ameliorate adverse effects of high doses of thiazide diuretics on insulin action.

A simple and direct method of turnround time audit in a microbiology laboratory

A method of specimen turnround time audit, directly controlled by laboratory staff, was applied to a bacteriology service to assess service efficiency and identify delays and other deficiencies, so that resources could be optimised. The method provided a complete collection of turnround time data and was easy to use. Delays of both administrative and technical natures were identified, and with minimal reorganisation the mean turnround time was improved.

Distribution of serotypes and antibiotic resistance among pneumococci in Northern Ireland

Altogether, 488 consecutive strains of Streptococcus pneumoniae isolated from clinical specimens were serotyped and their antibiotic susceptibility determined. Of all strains isolated, 89.7% (90.6% for strains isolated from patients with serious infection) were of types present in the new polyvalent (23-valent) pneumococcal vaccine. Four strains showed reduced susceptibility to penicillin (minimum inhibitory concentration 0.1-1.0 mg/l). Two of those strains (both serotype 23) were also of intermediate susceptibility to other antibiotics (ampicillin, cephradine, chloramphenicol and tetracycline) but were sensitive to erythromycin. A significant proportion (12%) was resistant to tetracycline.

Cyclical Cushing's disease: two distinct rhythms in a patient with a basophil adenoma

A 71-yr-old woman with clinical signs of Cushing's syndrome was studied continuously for an extended period after demonstration of a paradoxical response to dexamethasone. She proved to have a corticotroph cell adenoma of the pituitary which caused secretion of ACTH and cortisol in two distinct rhythms. One rhythm consisted of a period of 40 days of excess cortisol production, followed by a period of 60-70 days of normal production. During the period of excess cortisol production there was a second rhythm, consisting of peaks of cortisol production every 3-6 days with intervening troughs of normal cortisol production. Prolonged clinical remission followed transphenoidal surgery, but the pituitary still has the ability to provoke abnormal amounts of cortisol secretion, as occurred during a postoperative dexamethasone suppression test. The long duration of normal cortisol production phases in this patient demonstrates the difficulty in excluding Cushing's syndrome in patients with suggestive clinical symptoms but normal serum and urinary cortisol levels if these tests are measured for a single short phase of several days.