- Email: [email protected]
AT HOME WITH THE CARDIAC DEFIBRILLATOR
51 Consciousness began to return after 30-35 s. No saralainfused. sin Case 3.-A 24-year-old normotensive patient (blood-pressure 139/78 mm Hg) with renal scarring underwent frusemideinduced diuresis overnight, and became restless, sweaty, and pale as soon as the venous cannula was inserted the following morning. There was transient loss of consciousness with severe bradycardia and an unrecordable blood-pressure. Her clinical shock responded to saline. All three women had a severe hypotensive episode occurring after frusemide-induced diuresis, overnight fast, and insertion of an intravenous cannula. We believe that the clinical events were the result of significant extracellular fluid depletion caused by frusemide, potentiated by an overnight fast, and precipitated by a vasovagal attack associated with venous cannulation. A pilot study of the effects of 80 mg frusemide on seventeen normal subjects undergoing overnight fast showed a range of urine volume from 0.9 to 3-5litres. We now no longer administer frusemide on the evening before a saralasin study.
sure.
was
Department of Renal Medicine, University of Southampton, St Mary’s Hospital,
R. B. NAIK C. A. WILSON D. J. WARREN
Portsmouth PO3 6AD
SEX RATIO IN GLOMERULONEPHRITIS
SIR,-Dr Finn and Dr Harmer’s letter (June 2, p. 1194) showing that two-thirds of their patients with nephrotic symptoms are male may be important, but their data could be suspect because dialysis patients are even more highly selected than people attending a renal clinic. Only 16 people per million of the British population per annum receive dialysis,’1 while epidemiological studies have suggested that 40 per million per annum should receive this treatment.2 Finn and Harmer’s observation that two-thirds of their dialysis patients are male and that 84% of these men had nephritis reflects perhaps the pattern of referral and selection for dialysis and not the prevalence of nephritis. I fear that too many doctors in Britain have been bamboozled by the media into believing that dialysis facilities are insufficient; in many units the insufficiency is in the numbers of patients and nurses. Department of Renal Medicine, St. Mary’s Hospital,
ROGER GABRIEL
London W2
RADIOIMMUNOASSAY FOR FREE THYROXINE
SIR,-Debate
on
the accuracy and relevance of serum-free-
thyroxine (FT4) determinations has culminated in the correspondence between Professor Ekins and Professor Hennemann in your issue of June 2. The FT4 values under discussion were obtained with the Corning ’Immophase’ FT4 kit and were calculated from a knowledge of the respective count-rates of the two tubes of the assay expressed in the form A/B. We confirm that, as Professor Ekins pointed out, this method of calculation does underestimate FT4 in the presence of high thyroxine-binding globulin (TBG) concentrations and overestimates FT4 in the presence of low or undetectable concentrations of TBG. Our own laboratory evaluations confirm that this error is substantially overcome by using the modified rate calculation: which is equivalent
to
A/TxtT4 equation (iii) in Professor Ekins’ letter.
Equations (i) and (ii) are mathematical approximations of this equation. In samples containing normal concentrations of TBG this modified calculation made no significant difference to the values of FT4 obtained or to the clinical interpretation. In patients whose sera contained abnormal concentrations of TBG, but whose clinical status was euthyroid, the modified calculation gave values of FT4 which fell within the normal range. Accordingly, all users of Corning FT4 kits have been advised to use this modified calculation. Corning Medical, Corning Ltd,
dialysis
and
transplantation.
Brit Med
J 1978; ii: 1449-1450. 2 Office of Health Economics. Renal failure: Office of Health Economics, 1978.
a
priority
in health? London:
G. P. LIDGARD
AT HOME WITH THE CARDIAC DEFIBRILLATOR Dr Dellipiani’s first lament (May 19, the defibrillator into home care, I have p. 1089) bringing the inexpensive, lightweight British device suggested using (Pantridge 280, Cardiac Recorders, London).1 In Virginia, this miniature defibrillator has saved lives in home, office, street, and hospital. After correction of acute dysautonomia, relief of ischaemic chest pain and stabilisation of rhythm by drugs,3 the period "under the umbrella" of the defibrillator may safely be shortened in carefully selected patients.4 I sympathise with Dellipiani’s second, more serious complaint about the "overorganised, heavily pressured" N.H.S. If the N.H.S. inhibits the practitioner, alone or in groups, from caring efficiently for the coronary patient, British doctors must rise and assert themselves with tools and techniques at hand for some time.’
SiR,-With respect
to
about
Coronary
Care
System,
Cardiology Division, Department of Internal Medicine, University of Virginia School of Medicine, Charlottesville, Virginia 22908, U.S.A.
RICHARD CRAMPTON
ANTIBIOTIC PROPHYLAXIS FOR PATIENTS IN PROTECTIVE ISOLATION SIR,-Dr Watson and Dr Jameson (June 2, p. 1183) report that their NEOCON (neomycin, colistin, nystatin) regimen was as successful as FRACON, which had framycetin 500 mgx4, replaced by neomycin 500 mgx2 in the new regimen. This success might equally have been achieved with reduced oral framycetin. Framycetin is a more costly antibiotic, but it is also more effective.5Neomycin is a complex of neomycins A, B, and C. A is inactive as an antimicrobial, C has poor activity, and B is the fraction one depends on for any antimicrobial effect. Although it took the makers some time to admit to it, framycetin is identical with neomycin B. It would seem both reasonable treatment and economically wise to continue to use framycetin but in reduced dosage, perhaps 250 mg twice daily. Until such a trial is done the data recorded by Watson and Jameson can be interpreted in more than one way. Department of Microbiology, St James’ Hospital, London, SW12 8HW
BRYAN C. STRATFORD
Gascho J, Martin E. Taking coronary care to the patient. Lan1145-1146. 2. Gascho JA, Crampton RS, Cherwek ML, Sipes JN, Hunter FP, O’Brien WM. Determinants of ventricular defibrillation in adults. Circulation (in 1.
Crampton R,
cet 1978; i:
press). Pantridge JF, Adgey AAJ, Geddes JS, Webb SW. The acute coronary attack. Tunbndge Wells: Pitman Medical, 1975: 1-141. 4. Wilson C, Pantrdige JF: S-T segment displacement and early hospital discharge in acute myocardial infarction. Lancet 1973; ii: 1284-1288. 5. Stratford BC, Dixson S. Intestinal asepsis with neomycin and framycetin: a comparative study. Med J Aust 1964; i: 74. 3.
1. Anonymous. Selection of patients for
J. FULLARTON
Halstead, Essex C09 2DX
sure.
was
Department of Renal Medicine, University of Southampton, St Mary’s Hospital,
R. B. NAIK C. A. WILSON D. J. WARREN
Portsmouth PO3 6AD
SEX RATIO IN GLOMERULONEPHRITIS
SIR,-Dr Finn and Dr Harmer’s letter (June 2, p. 1194) showing that two-thirds of their patients with nephrotic symptoms are male may be important, but their data could be suspect because dialysis patients are even more highly selected than people attending a renal clinic. Only 16 people per million of the British population per annum receive dialysis,’1 while epidemiological studies have suggested that 40 per million per annum should receive this treatment.2 Finn and Harmer’s observation that two-thirds of their dialysis patients are male and that 84% of these men had nephritis reflects perhaps the pattern of referral and selection for dialysis and not the prevalence of nephritis. I fear that too many doctors in Britain have been bamboozled by the media into believing that dialysis facilities are insufficient; in many units the insufficiency is in the numbers of patients and nurses. Department of Renal Medicine, St. Mary’s Hospital,
ROGER GABRIEL
London W2
RADIOIMMUNOASSAY FOR FREE THYROXINE
SIR,-Debate
on
the accuracy and relevance of serum-free-
thyroxine (FT4) determinations has culminated in the correspondence between Professor Ekins and Professor Hennemann in your issue of June 2. The FT4 values under discussion were obtained with the Corning ’Immophase’ FT4 kit and were calculated from a knowledge of the respective count-rates of the two tubes of the assay expressed in the form A/B. We confirm that, as Professor Ekins pointed out, this method of calculation does underestimate FT4 in the presence of high thyroxine-binding globulin (TBG) concentrations and overestimates FT4 in the presence of low or undetectable concentrations of TBG. Our own laboratory evaluations confirm that this error is substantially overcome by using the modified rate calculation: which is equivalent
to
A/TxtT4 equation (iii) in Professor Ekins’ letter.
Equations (i) and (ii) are mathematical approximations of this equation. In samples containing normal concentrations of TBG this modified calculation made no significant difference to the values of FT4 obtained or to the clinical interpretation. In patients whose sera contained abnormal concentrations of TBG, but whose clinical status was euthyroid, the modified calculation gave values of FT4 which fell within the normal range. Accordingly, all users of Corning FT4 kits have been advised to use this modified calculation. Corning Medical, Corning Ltd,
dialysis
and
transplantation.
Brit Med
J 1978; ii: 1449-1450. 2 Office of Health Economics. Renal failure: Office of Health Economics, 1978.
a
priority
in health? London:
G. P. LIDGARD
AT HOME WITH THE CARDIAC DEFIBRILLATOR Dr Dellipiani’s first lament (May 19, the defibrillator into home care, I have p. 1089) bringing the inexpensive, lightweight British device suggested using (Pantridge 280, Cardiac Recorders, London).1 In Virginia, this miniature defibrillator has saved lives in home, office, street, and hospital. After correction of acute dysautonomia, relief of ischaemic chest pain and stabilisation of rhythm by drugs,3 the period "under the umbrella" of the defibrillator may safely be shortened in carefully selected patients.4 I sympathise with Dellipiani’s second, more serious complaint about the "overorganised, heavily pressured" N.H.S. If the N.H.S. inhibits the practitioner, alone or in groups, from caring efficiently for the coronary patient, British doctors must rise and assert themselves with tools and techniques at hand for some time.’
SiR,-With respect
to
about
Coronary
Care
System,
Cardiology Division, Department of Internal Medicine, University of Virginia School of Medicine, Charlottesville, Virginia 22908, U.S.A.
RICHARD CRAMPTON
ANTIBIOTIC PROPHYLAXIS FOR PATIENTS IN PROTECTIVE ISOLATION SIR,-Dr Watson and Dr Jameson (June 2, p. 1183) report that their NEOCON (neomycin, colistin, nystatin) regimen was as successful as FRACON, which had framycetin 500 mgx4, replaced by neomycin 500 mgx2 in the new regimen. This success might equally have been achieved with reduced oral framycetin. Framycetin is a more costly antibiotic, but it is also more effective.5Neomycin is a complex of neomycins A, B, and C. A is inactive as an antimicrobial, C has poor activity, and B is the fraction one depends on for any antimicrobial effect. Although it took the makers some time to admit to it, framycetin is identical with neomycin B. It would seem both reasonable treatment and economically wise to continue to use framycetin but in reduced dosage, perhaps 250 mg twice daily. Until such a trial is done the data recorded by Watson and Jameson can be interpreted in more than one way. Department of Microbiology, St James’ Hospital, London, SW12 8HW
BRYAN C. STRATFORD
Gascho J, Martin E. Taking coronary care to the patient. Lan1145-1146. 2. Gascho JA, Crampton RS, Cherwek ML, Sipes JN, Hunter FP, O’Brien WM. Determinants of ventricular defibrillation in adults. Circulation (in 1.
Crampton R,
cet 1978; i:
press). Pantridge JF, Adgey AAJ, Geddes JS, Webb SW. The acute coronary attack. Tunbndge Wells: Pitman Medical, 1975: 1-141. 4. Wilson C, Pantrdige JF: S-T segment displacement and early hospital discharge in acute myocardial infarction. Lancet 1973; ii: 1284-1288. 5. Stratford BC, Dixson S. Intestinal asepsis with neomycin and framycetin: a comparative study. Med J Aust 1964; i: 74. 3.
1. Anonymous. Selection of patients for
J. FULLARTON
Halstead, Essex C09 2DX