EFFECT OF HIGH THORACIC EXTRADURAL ANAESTHESIA ON VENTILATORY RESPONSE TO HYPERCAPNIA IN NORMAL VOLUNTEERS

We have investigated, in six healthy male volunteers, the effectof high thoracic extradural anaesthesia on the ventilatory patternand hypercapnic ventilatory response. Ventilatory variableswere determined using a respiratory inductive plethysmograph.Duration of inspiration, rib cage excursion and its contributionto tidal volume decreased significantly following extraduralanaesthesia, while mean inspiratory flow rate and minute ventilationincreased. End-tidal PCO₂ and the tidal excursion of the abdomenwere unchanged. Hypercapnic ventilatory response decreased significantlyfollowing extradural anaesthesia, principally because of therib cage component. The slope of the abdominal component didnot change significantly. The results indicate that mechanicalimpairment of rib cage movement can produce decreased ventilatoryresponse to carbon dioxide. The ventilatory impairment and thechanges in breathing pattern induced by the high thoracic extraduralanaesthesia probably reflect blockade of the efferent or afferentpathway (or both) of the intercostal nerve roots.     

Haemophagocytic lymphohistiocytosis in association with granular lymphocyte proliferative disorders in early childhood: characteristic bone marrow morphology

Five paediatric cases of haemophagocytic lymphohistiocytosis (HLH) which showed proliferation of granular atypical lymphocytoid cells in bone marrow are reported. All cases were girls aged 8 months to 4 years who had marked hepatosplenomegaly. Marker analysis on peripheral blood mononuclear cells revealed an increase in the CD3⁺HLADR⁺ subset in three cases and the CD³⁻CD56⁺ subset in one case. An Epstein-Barr virus genome was detected in three cases, and monoclonality was confirmed in two cases. A characteristic morphology of large granular lymphocytes (LGL) was identified, with elongated bizarre features that resembled horsetail-, tadpole-, cucumber- or shooting star-type configurations on the bone marrow smear. Serum concentrations of soluble interleukin-2 receptor and interferon-gamma were elevated in all cases. All five cases required multi-agent chemotherapy which resulted in two complete remissions, two partial remissions and one no response. Refinement of treatment is required for these paediatric GLPD cases which probably comprise a specific high-risk subgroup among secondary HLH patients which had previously escaped notice.