Karl Young

Comparison of the USCOM ultrasound cardiac output monitor with pulmonary artery catheter thermodilution in patients undergoing liver transplantation.

The aim of the study was to compare the standard technique of cardiac output determination by pulmonary artery catheter thermodilution (PAC‐TD) with a noninvasive ultrasound Doppler monitor (USCOM Pty., Ltd., Coffs Harbour, Australia) in surgery for liver transplantation. We wished to determine if the degree of accuracy would allow the ultrasound cardiac output monitor (USCOM) to be used as an alternative monitor in a clinical setting in which wide fluctuations in cardiac output could be expected. This was a prospective method comparison study, with 71 paired measurements obtained in 12 patients undergoing liver transplantation in a university teaching hospital. Bland‐Altman analysis of the 2 techniques showed a bias of 0.39 L/minute, with the USCOM cardiac output lower compared with that of PAC‐TD. The bias was small and did not vary with the magnitude of the cardiac output. The 95% limits of agreement were −1.47 and 2.25 L/minute. There was good repeatability for USCOM measurements, with a repeatability coefficient of 0.43 for USCOM versus 0.77 for PAC‐TD. We conclude that USCOM is acceptable for the clinical determination of noninvasive cardiac output, particularly in situations in which tracking changes over time is more important than knowing the precise value. However, the utility of USCOM is limited by its inability to measure pulmonary artery pressure. Liver Transpl 14:1038–1043, 2008.

Adult Croup: A Rare but More Severe Condition

We report the first adult patient with virologically confirmed croup caused by parainfluenza virus type 3 and review 10 cases of adult croup described in the English-language literature. Circumstantial evidence of viral infection was present in only 1 other case, in which there was a rise in antibody titer against influenza B virus. Ten patients (91%) required intensive care support. None of the 11 patients died. A comparison was also made between the 11 adults with croup and 43 children hospitalized with severe croup described in a representative paper published in 1984. Adult croup represents an apparently more severe disease entity than pediatric croup.

Unexpected glucose‐6‐phosphate dehydrogenase deficiency

A 50-year-old man with refractory intestinal T-cell lymphoma was started on combination chemotherapy (ifosfamide, methotrexate, l-asparaginase, etoposide, dexamethasone). Cotrimoxazole was commenced for pneumocystis prophylaxis after a normal glucose-6-phosphate dehydrogenase (G6PD) spot fluorescence screen [>4Æ5 iu/g haemoglobin (Hb)]. Initial tumour shrinkage was accompanied by renal impairment (creatinine 393 lmol/l, normal 67–109) and hyperuricaemia (1259 lmol/l, normal 260–530), and rasburicase (4Æ5 mg · 1 dose) was given for tumour lysis. Despite a dramatic fall in uric acid level (55 lmol/l), anaemia suddenly occurred (Hb fell from 113 g/l to 59 g/l), followed by hypotension and oliguria. Biochemical screening showed raised unconjugated bilirubin (41 lmol/l, normal <6) and lactate dehydrogenase (798 iu/l, normal 118–211). Intravascular haemolysis was confirmed by raised methaemalbumin (14Æ3 mg/l, normal <01Æ0) levels and haemoglobinuria. A peripheral blood film showed bite cells and abundant hemighost cells (left), classical for oxidative haemolysis. The patient survived with transfusion, haemodialysis and supportive treatment, with complete renal recovery. A repeat G6PD enzyme assay on his stored blood sample showed a marginal G6PD level of 5Æ5 iu/g Hb, which lies within the range expected for female heterozygotes. His four brothers were all G6PD deficient (0Æ21–1Æ24 iu/g Hb). Using allelespecific polymerase chain reaction, a G6PD Kaiping allele (nt 1388 G fi A) was detected in the patient and all siblings. Surprisingly the patient also carried a second normal G6PD allele, suggesting extra X chromosome material. On further questioning, the patient volunteered a history of azoospermia and bilateral absent vas deferens. There were no other abnormal features suggestive of Klinefelter syndrome. Karyotype analysis on stimulated peripheral blood lymphocytes and fluorescence in situ hybridization with an X whole chromosome painting probe (Oncor Inc., Gaithersburg, MD, USA) confirmed the presence of extra X chromosome material on the Y-chromosome (right, red arrow) in all 20 metaphases analysed: 46, XY.ish add(Y)(p11)(wcpX+). Hence the patient was an occult carrier of extra X chromosome material and a heterozygous carrier of G6PD deficiency. Deficiency of G6PD is the commonest red cell enzymopathy world-wide. It affects 4Æ8% of all Southern Chinese males, and is screened for at birth and before the commencement of oxidative medications. In female heterozygotes, random lyonization of the X chromosomes results in a mixture of normal and G6PD deficient red cells. The resultant average enzyme levels usually lie within the normal range. However female heterozygotes for G6PD deficiency can still suffer haemolysis as a result of skewed lyonization because of age, haemopoietic transplantation or clonal haemopoiesis. Without mandatory screening, this can cause unexpected severe haemolysis. Our case showed that a simple fluorescent screen might still be insufficient. Severe oxidative stresses because of a combination of drugs (cotrimoxazole and rasburicase) could still cause en masse destruction of the G6PD deficient subpopulation, resulting in life-threatening intravascular haemolysis. Hence, a quantitative enzyme level assay is a better option in areas endemic for G6PD deficiency.

Developments in trauma management: From the field to the intensive care unit

There have not been dramatic changes in trauma management in recent years. Nevertheless, there are noteworthy developments that might eventually change both paradigms of trauma systems and clinical management. In the present study, organizational aspects of mass casualty scenarios and what we have learned from the experiences of military doctors are examined. Then, the perennial theme of fluid resuscitation; when, what and how much to give, is examined. The management of bleeding and minimization of allogeneic blood transfusions raise the topics of recombinant factor VIIa and oxygen carrying blood substitutes. Finally, an aspect of intensive care management that is very topical, that of immunonutrition and the modulation of sepsis in intensive care, is examined.

Complication of venovenous extracorporeal membrane oxygenation cannulation – the significance of an inferior vena cava anomaly

Physicians should be aware of possible anatomical variants during cannulation for extracorporeal membrane oxygenation (ECMO). Particular attention to ensure continual visualization of the guidewire before proceeding to final positioning of the ECMO cannulae should be paid. Alternative imaging modalities should be contemplated when uncertainties arise to minimize the risk of inadvertent vascular injuries.