AMNIOPLASTIN: NEW REAGENT FOR COAGULATION TESTS

251 CARDIAC MASSAGE: HOW VIGOROUS?

I suggest that this human tissue

massage and mouth-to-mouth breathing can as broken ribs, often result from overvigorous cardiac massage. Survivors may think this is a small price to pay, but such injuries are avoidable. We set up a simple experiment to see what pressures would be exerted by trained operators. The patient was simulated by placing spring scales on a block raised to approximately the level of the chest of a supine male patient. Men and boys from the 100/3 Bricklayers Arms Division of the St John Ambulance volunteered to take part. They were asked to assess the pressure which they were applying and to demonstrate the maximum pressure they could exert. Of the forty-four praticipants twenty-two were aged 11-17, twelve were between 18 and 29, and ten were aged 30-65. They weighed 36-119 kg (mean 67 kg). The members were divided by age into 11-17 years and 18 years and upwards. The maximum pressures exerted were 39 kg for the younger group and 50 kg for the older group. These represented 72% and 62%, respectively, of personal weights. The maximum pressure exerted wasremarkably constant at about two-thirds

SIR,-Cardiac

save

lives, but complications, such

of body-weight. The ambulancemen had no idea how hard they were pressing--estimates varied from 7% to 300% of actual pressures. The mean was about 60%-i.e., a 70 kg man would think he was exerting 28 kg when he was really giving 47 kg. There was no relationship between the inability to guess and the degree of training, age, body-weight, or any other factor. Very few patients would have survived massage from this trained group without multiple injuries. National Heart Hospital, London W1M 8BA National Heart and Chest London W1

D. B. LONGMORE Hospitals,

M. REHAHN

John Ambulance Brigade, 100/3 Bricklayers Arms Division, London NW3 St.

C. R. DIPPLE

AMNIOPLASTIN: NEW REAGENT FOR COAGULATION TESTS

SIR,-The coagulation properties of the amniotic

mem-

well known.’-3 We have investigated the amniotic membrane, obtaining an extract with a known concentration which was used in a coagulation trial. By this experiment we have demonstrated that the use of the amniotic membrane transplant was justified.4 The results are summarised in the table. brane

are

1. Rendelstein, F. D., Frischauf, H., Deutsch, E. Acta hœmat. 1951, 6, 18. 2. Weiner, A. E., Reid, D. E., Roby, C. C. Science, 1949, 110, 190. 3. Courtney, L. D., Allington, M. Br. J. Hœmat. 1972, 33, 353. 4. Creter, D., Rubinstein, J., Laurian, N. Israel J. med. Sci. 1977, 13, 448.

thromboplastin be tried for instead of rabbit-brain thromboplastin. The material is simply obtained and in large amounts, and this work could result in a cheaper reagent. If the W.H.O. and the National (U.K.) Reference Laboratory for Anticoagulant Control Reagents agree, an international standardisation with the aid of the British comparative thromboplastin will be of help.

laboratory

use

Department of Hæmostasis, Clinical Laboratories, Hasharon Hospital, Petah-Tiqva, Israel

LITHIUM-INDUCED GRANULOCYTOSIS

SIR,-Dr Charron and his colleagues describe how they shortened the period of drug-induced granulopenia by the administration of lithium in patients with acute myelogenous leukxmia. We have seen a similar effect of lithium carbonate in

intensive combination chemotherapy lymphosarcoma.2 Greco et awl. have demonstrated a marrow-protective effect of lithium in patients receiving chemotherapy for advanced malignancy. Furthermore, granulocytosis occurs in patients without malignancy who are taking lithium carbonate for psychological disorders.4.5 Further work by Bille et al. has shown that lithium administration is associated with an increase in the platelet-count. Shenkman et at.7 demonstrated significant immunostimulatory activity of lithium in both mouse and man: lithium enhanced phytohmmagglutinin-induced stimulation of human lymphocytes and also enhanced phagocytosis of latex particles by human mononuclear cells. A possible explanation for lithium-induced granulocytosis has been offered by Harker and Rothstein8 who showed that lithium chloride can trigger colony-stimulating-factor production by human mononuclear cells. Morley and Galbraith9 suggest that lithium may potentiate the action of colony-stimulating factor. Besides its immunological and haematological effects, lithium is therapeutic in cases of inappropriate secretion of antidiuretic hormone (A.D.H.) and has been used to decrease anxiety in patients with acute granulocytic leukaemia.1 Patients whom we have treated for malignancy with lithium carbonate have not had problems with lithium toxicity pro-

patients undergoing

for

vided the serum-lithium is in the range O-S-1-5mmol/l. However, if the serum-sodium drops below normal, even so-called safe therapeutic concentrations of lithium have proved to be toxic. Frequent monitoring of serum lithium and sodium concentrations can prevent most toxic episodes. Lithium carbonate seems to have the potential of being a 1. Charron, D., and others Lancet, 1977, i, 1307. 2. Tisman, G., I.R.C.S. 1974, 2, 1509. 3. Greco, F. A. and others Proc. A. Meet. Am. Soc. clin. Oncol. 1976, 4. Shopsin, B., Friedman, R., Gershon, S. Clin. Pharmac. Ther. 1971, 5. Tisman, G., Herbert, V., Rosenblatt, S. Br. J. Hœmat. 1972, 24, 767. 6. Bille, P. E., and others Acta med. scand. 1975, 198, 281. 7. Shenkman, L., and others Clin. Res. 1976, 27, 634. 8. Harker, G. W., Rothstein, G. ibid. 1975, 23, 103A. 9. Morley, D. C., Galbraith, P. R. ibid. 1976, 24, 671.

(A) NORMAL PLASMA, (B) NORMAL PLASMA WITH (C) NORMAL PLASMA WITH AMNIOTIC MEMBRANE EXTRACT 1/1

COMPARATIVE TRIAL OF SOME COAGULATION TESTS USING:

T.E.G.=thromboelastogram; for platelet-poor plasma.

DRAGA CRETER

SALINE MIXED

1/1,

17, 250. 12, 923.

AND