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M A Mohammed

Publications and source records attributed to M A Mohammed.

8 recordsLinked to original sources

Bristol, Shipman, and clinical governance: Shewhart's forgotten lessons.

During the past century, manufacturing industry has achieved great success in improving the quality of its products. An essential factor in this success has been the use of Walter A Shewhart's pioneering work in the economic control of variation, which culminated in the development of a simple yet powerful graphical method known as the control chart. This chart classifies variation as having a common cause or special cause and thus guides the user to the most appropriate action to effect improvement. Using six case studies, including the excess deaths after paediatric cardiac surgery seen in Bristol, UK, and the activities of general practitioner turned murderer Harold Shipman, we show a central role for Shewhart's approach in turning the rhetoric of clinical governance into a reality.

Adult↗

Oxygen and 99mTc-MAA shunt estimations in patients with pulmonary arteriovenous malformations: effects of changes in posture and lung volume.

BACKGROUND: Patients with arteriovenous malformations are routinely monitored with arterial oxygen saturation (SaO2) estimations (breathing air) from which an oxygen shunt fraction can be calculated. This simple estimation has been compared with an anatomically defined estimate of the right to left shunt using a radioisotopic method. The fall in SaO2 which occurs in patients with pulmonary arteriovenous malformations in the erect posture and at high lung volumes was used to test the ability of SaO2 alone to follow changes in right to left shunt. METHODS: Radiolabelled albumin macroaggregates (99mTc-MAA) or microspheres (MS) were injected intravenously and kidneys and lungs were imaged. The shunt fraction (QS/QTTc) in the supine position at functional residual capacity (baseline) was obtained by quantifying right kidney radioactivity. On standing or while breath holding at total lung capacity, shunt fraction was calculated from baseline QS/QTTc and from lung counts and the injected dose. Arterial oxygen saturation (SaO2) was recorded by a pulse oximeter for calculation of the oxygen shunt (QS/QTO2) (breathing air). RESULTS: In the postural study (n = 8) SaO2 decreased from a mean (SD) value of 89 (5)% supine to 80 (6)% erect, corresponding to QS/QTO2 28 (8)% and 44 (8)% respectively. QS/QTTc increased from 28.7 (10.3)% to 39 (14.3)%. In the lung volume study (n = 8) QS/QTTc increased from 16.6 (11.5)% at functional residual capacity to 23.3 (11.9)% at total lung capacity while QS/QTO2 increased from 19.5 (7.5)% to 25.9 (10.6)% respectively. When all measurements were compared for QS/QTTc% and QS/QTO2% (n = 32) the difference in the mean values was 2.5% (absolute) and the limits of agreement between the two methods were +38% to -18% (relative). In neither the postural nor the volume study did delta (QS/QTO2) reliably predict delta (QS/QTTc)%. CONCLUSIONS: In pulmonary arteriovenous malformations the simple physiological shunt calculated from SaO2 breathing air agreed well with the anatomical right to left shunt measured with 99mTc-MAA, but predicted poorly the changes in anatomical shunt induced by postural or lung volume changes.

Adult↗

Rotational frequencies of methyl group tunneling.

Methyl tunnel frequencies, measured at 4 K, are found to be 455 +/- 8 kHz in methyl malonamide and 496 +/- 8 kHz in methyl ethyl ketone. The first is unaffected by deuteration of the amide groups. Measurements of the temperature dependence of the spin lattice relaxation time are also reported for methyl malonamide and a further test is made of a previously reported correlation between tunnel frequency and the temperature of the T1 minimum. The measurements are in good agreement with the universal correlation curve.

Butanones↗

Experimental study of contagious paralysis of pigeons.

A study of the clinical and pathological changes in pigeons experimentally inoculated with a herpesvirus isolated recently from natural cases of a condition termed contagious paralysis was carried out. Signs and pathological findings similar to those recorded in natural cases were produced after inoculation of the isolate via different routes. The incubation period differed according to the route of inoculation from 2 to 10 days and the course of the disease from 5 to 21 days. The mortality ranged from 100% in the intracerebrally inoculated pigeons to 61% in the orally infected ones. The clinical signs and the gross and histopathological changes included mainly progressive paralysis, meningo-encephalomyelitis, pancreatitis and sometimes enteritis.

Animals↗

Job satisfaction.

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Job Satisfaction↗