- Email: [email protected]
POTENTIAL HAZARDS OF VIGGO INTRAVENOUS CANNULÆ
1239 fluid meniscus cannot be removed so a small residum of fluid is injected into the patient with the next intravenous medication. The principle of having a membrane through which intermittent therapy can be given into intravenous cannulae was introduced by T. G. Olovson in 1948; the membrane was flush with the catheter hub, and Olovson recommended cleaning the membrane with alcohol or ether after each injection. However, the inaccessibility of the diaphragm of the venflon side port makes this effective precaution
proliferate. The
impracticable. (2) The base of the side port contains a non-return valve and if this should fail, the defect would be almost impossible to detect: the major hazards would then be air in the circulation or the introduction of infection. (3) The design of the central venous catheters includes a stopcock tap as an integral part of the hub. Stopcocks accumulate fluid in their interstices and have a high incidence of bacterial contamination.2 The presence of the tap could overstress the hub and cause fracturing, with resultant air embolism.3 This complication is ttnown to the D.H.S.S. Three-way taps linked to central catheters can fracture with daily use.
population (see U.I.C.C.
publication Cancer in
University College Hospital,
J. L. PETERS
London WC1E 6AU
University College Hospital Medical School, London WC1
limited to persons over the age of 60, and was therefore ascribed to improvements in diagnosis in the elderly. This seems to be confirmed by the fact that the rise ceased first in Copenhagen and last in the rural areas when rates had reached almost the same level as that in the capital. A general view of the data from the Danish Cancer Registry since 1943 (see table) suggests slightly more constant rates for females than for males. A detailed analysis has shown that, in about 1969, improvement in differential diagnosis transferred some cases from unspecified acute cases to acute lymphoid and myeloid leukaemias, but, as the rates show, this has not sufficed to avert a slight apparent downward trend for the last four years on record. Absolute numbers are constant for myeloid cases, acute and chronic. For acute lymphatic leukaemia there may be a slight upward trend in both sexes, while the trend for chronic lymphatic leukaemia in males is uncertain, females showing more constant figures. The two diseases show different age distribution, and age-adjustment may influence their rates differently. Either way we can be sure that the latest years have not seen a continuation of the rise mentioned by Geary et al. The figures from Denmark thus contrast with the rising incidence for acute and chronic myeloid leukaemia reported for Lancashire, and could be interpreted as supporting the hypothesis that environmental leukaemogens are present in Lancashire. rates
North Middlesex London N18
C. FISHER
Hospital,
S. MEHTAR
Bf IN EARLY-ONSET INSULIN-DEPENDENT DIABETES
SIR,-Dr Kirk and colleagues (Sept. 8, p. 537) have reported that the association between the rare Bf allele Fl and insulin-dependent diabetes (IDDM or type I) is strongest for patients below age 10 at the time of study. 19% were positive below age ten in contrast to less than 2% after age twenty. Dr Bernal and colleagues (Nov. 3, p. 961) found that 4 out of 5 Fl positive patients had onset of disease below age seventeen. We have found only 6 diabetics with Fl in 124 patients (4-8%), 100 of whom were reported on in your issue of Aug. 18 (p. 369). The table shows the distribution of Flpositive diabetics as a function of age at study and at diagnosis. Age at diagnosis is the more meaningful indicator. AGE AT STUDY AND AT DIAGNOSIS AND
FREQUENCY OF Bf ALLELE
Fl
Cancer Registry, Finsen Institute,
JOHANNES CLEMMESEN
Copenhagen 2100, Denmark
POTENTIAL HAZARDS OF VIGGO INTRAVENOUS CANNULÆ
SIR,-In June, 1979, the Department of Health and Social
Security issued a hazard warning notice about Viggo ’Venflon’ intravenous cannulae, drawing attention to the risk of the attached administration sets becoming disconnected from the luer hub of the cannula. The notice was subsequently withdrawn without any apparent changes in the product. There are several potential dangers in the Viggo cannulae (marketed in the U.K. by British Viggo [British Oxygen Corporation]). (1) The injection port acts as a sump in which bacteria may
If we pool our patients with onset below age seventeen with those of Bernal et al., there are 104 IDDM patients with diagnosis of disease below age seventeen, and 9 (8.7%) of these are positive for Fl. Only 2 out of 84 patients with onset at age seventeen or over are positive (2%). Our data suggest that a 1. Pilsworth RC. Intravenous catheiers. Lancet 1978; ii: 1386. 2. Dryden GE, Brickler J. Anæsth Analg 1979; 58: 141. 3. Armstrong R, Peters JL, Cohen SL. Air embolism caused by fractured tral-venous catheter. Lancet 1977; i: 954. 4. DHSS. Health notice HN (hazard) (77) 21.
cen-
proliferate. The
impracticable. (2) The base of the side port contains a non-return valve and if this should fail, the defect would be almost impossible to detect: the major hazards would then be air in the circulation or the introduction of infection. (3) The design of the central venous catheters includes a stopcock tap as an integral part of the hub. Stopcocks accumulate fluid in their interstices and have a high incidence of bacterial contamination.2 The presence of the tap could overstress the hub and cause fracturing, with resultant air embolism.3 This complication is ttnown to the D.H.S.S. Three-way taps linked to central catheters can fracture with daily use.
population (see U.I.C.C.
publication Cancer in
University College Hospital,
J. L. PETERS
London WC1E 6AU
University College Hospital Medical School, London WC1
limited to persons over the age of 60, and was therefore ascribed to improvements in diagnosis in the elderly. This seems to be confirmed by the fact that the rise ceased first in Copenhagen and last in the rural areas when rates had reached almost the same level as that in the capital. A general view of the data from the Danish Cancer Registry since 1943 (see table) suggests slightly more constant rates for females than for males. A detailed analysis has shown that, in about 1969, improvement in differential diagnosis transferred some cases from unspecified acute cases to acute lymphoid and myeloid leukaemias, but, as the rates show, this has not sufficed to avert a slight apparent downward trend for the last four years on record. Absolute numbers are constant for myeloid cases, acute and chronic. For acute lymphatic leukaemia there may be a slight upward trend in both sexes, while the trend for chronic lymphatic leukaemia in males is uncertain, females showing more constant figures. The two diseases show different age distribution, and age-adjustment may influence their rates differently. Either way we can be sure that the latest years have not seen a continuation of the rise mentioned by Geary et al. The figures from Denmark thus contrast with the rising incidence for acute and chronic myeloid leukaemia reported for Lancashire, and could be interpreted as supporting the hypothesis that environmental leukaemogens are present in Lancashire. rates
North Middlesex London N18
C. FISHER
Hospital,
S. MEHTAR
Bf IN EARLY-ONSET INSULIN-DEPENDENT DIABETES
SIR,-Dr Kirk and colleagues (Sept. 8, p. 537) have reported that the association between the rare Bf allele Fl and insulin-dependent diabetes (IDDM or type I) is strongest for patients below age 10 at the time of study. 19% were positive below age ten in contrast to less than 2% after age twenty. Dr Bernal and colleagues (Nov. 3, p. 961) found that 4 out of 5 Fl positive patients had onset of disease below age seventeen. We have found only 6 diabetics with Fl in 124 patients (4-8%), 100 of whom were reported on in your issue of Aug. 18 (p. 369). The table shows the distribution of Flpositive diabetics as a function of age at study and at diagnosis. Age at diagnosis is the more meaningful indicator. AGE AT STUDY AND AT DIAGNOSIS AND
FREQUENCY OF Bf ALLELE
Fl
Cancer Registry, Finsen Institute,
JOHANNES CLEMMESEN
Copenhagen 2100, Denmark
POTENTIAL HAZARDS OF VIGGO INTRAVENOUS CANNULÆ
SIR,-In June, 1979, the Department of Health and Social
Security issued a hazard warning notice about Viggo ’Venflon’ intravenous cannulae, drawing attention to the risk of the attached administration sets becoming disconnected from the luer hub of the cannula. The notice was subsequently withdrawn without any apparent changes in the product. There are several potential dangers in the Viggo cannulae (marketed in the U.K. by British Viggo [British Oxygen Corporation]). (1) The injection port acts as a sump in which bacteria may
If we pool our patients with onset below age seventeen with those of Bernal et al., there are 104 IDDM patients with diagnosis of disease below age seventeen, and 9 (8.7%) of these are positive for Fl. Only 2 out of 84 patients with onset at age seventeen or over are positive (2%). Our data suggest that a 1. Pilsworth RC. Intravenous catheiers. Lancet 1978; ii: 1386. 2. Dryden GE, Brickler J. Anæsth Analg 1979; 58: 141. 3. Armstrong R, Peters JL, Cohen SL. Air embolism caused by fractured tral-venous catheter. Lancet 1977; i: 954. 4. DHSS. Health notice HN (hazard) (77) 21.
cen-