1301
found. The authors continue "During this manic phase he came across a piece of fabric with a picture of Jerusalem on it. He wanted to hide this in a safe place and immediately thought of doing so behind a painting hanging on the wall in the sitting room. When he moved the painting to push the cloth behind it, a large envelope containing the missing L3000 fell to the floor." What is not clear is whether the hiding place was rediscovered because the patient’s mood was the same, or because he found himself again wanting to hide something valuable. If the events are ever repeated, perhaps the doctor should encourage the patient to hide a further c3000 during his normal mood state, in which case the original C3000 might be recovered without waiting for a recurrence of the mania. It is not surprising that recall is best for memories that are relevant to the person’s current circumstances and to whatever he or she is doing and feeling at the time. It would not have been adaptive for our hunter-gatherer ancestors if their minds had been occupied with memories of hunting while they were gathering, or with memories of gathering while they were hunting-unless, of course, the hunting or gathering was going badly. If that was the case they might well have switched from the pursuit of one goal to the pursuit of another, and when motivation changes, memory, along with most other mental functions, is likely to be affected.7,8Thus scuba divers who are frustrated with scuba diving might well have better recall for information about water skiing than about scuba diving, whether the new information is presented under water or in the classroom.
mania, that the as
1. Godden
money
was
follows:
D, Baddely AD. Context-dependent
memory in two natural
environments. Br J Pschol 1975; 71: 99-104 2. Goodwin DW, Powell B, Bremer D. Alcohol and recall: state dependent effects in man. Science 1968; 163: 1358-60. 3. Eich JE. The cue-dependent nature of state-dependent retrieval. Mem
Cogn 1980; 8: 157-73. 4. Raush HL, Barry WA, Hertel RK, Swain MA. Communication, conflict and marriage. San Francisco: Jossey-Bass, 1974. 5. Gray P. Psychology. New York: Worth, 1991. 6. Williams JMG, Markar HR. Money hidden and rediscovered in subsequent manic phases: a case of action dependent mood state? Br J Psychiatry 1991; 159: 579-81. 7. Toates FM. Models of motivation. In: Toates FM, Halliday TR, eds. Animal behaviour. Vol 1, causes and effects. Oxford: Blackwell, 1983. 8. Klinger E. Consequences of commitment to and disengagement from incentives. Psychol Rev 1975; 82: 1-25.
Central
venous access
in children
Central venous catheters have many applications in children. The indications are commonest
chemotherapy
of
disease and total parenteral nutrition; children with other conditions requiring intermittent courses of treatment (eg, cystic fibrosis, haemophilia, and thalassaemia) may likewise benefit from this approach.l The central vein may be entered directly, either surgically or percutaneously, or indirectly via a peripheral vein; the catheter tip
malignant
should lie in the superior vena cavaz or the right atrium.3 In oncology, subcutaneous venous access reservoirs (eg, ’Portacath’, ’Mediport’) or tunnelled lines with a subcutaneous cuff for fixation and an external connection (eg, ’Hickman’, ’Broviac’) are commonly used. A questionnaire study4 of parents’ and patients’ reactions showed that after one year 95% of patients with subcutaneous devices were satisfied, as were 97% with external devices. Only 16% of patients were unhappy that a needle is required to gain access to a subcutaneous device (use of a topical anaesthetic before needle puncture can help in this respects) and only 3% of those with external devices found the need for regular flushing troublesome. Although both types of access are suitable for intermittent use, subcutaneous devices are not so suitable for long-term, continuous intravenous treatment because the skin over the reservoir may ulcerate. Patients can ignore the presence of the subcutaneous device when it is not in use, whereas external catheters require regular dressing and flushing. Nevertheless, the flushing procedure can be simplified, since weekly flushing with saline6 or, preferably, a bacteriostatic solutionis as satisfactory as
daily flushing with an anticoagulant.
Selection of method of access is likewise important in patients requiring long-term intravenous nutrition, especially in newborn babies. Broviac-type catheters are valuable, but they require surgical insertion into a central vein, which may subsequently become occluded. If catheters have to be removed because of infection or mechanical complications, it may become increasing difficult to find veins of adequate calibre. Fine silastic catheters inserted via a peripheral vein8,9 can overcome this difficulty. These catheters are most successful if used exclusively for parenteral nutrition, with the line being breached no more than once daily When peripheral venous access is impossible or the central venous line is required for multiple uses, the wider calibre Broviac-type catheter (or possibly, in larger infants and children, a multilumen catheter) is more
appropriate.
Silastic
is
the
most popular material but less prone to thrombus be polyurethane may formation and sepsis.11 One report9 suggested that the tip of polyurethane catheters is harder than silastic and therefore such catheters would not be appropriate for newborn babies. Catheters can become dislodged despite the subcutaneous cuff ;2 a new design of polyurethane device may help in this respect." Higher rates of catheter infection have been recorded in newborn babies than in older children. 12,13 Because of difficulties with peripheral, and even repeated central, venous access in this age group, the possibility of treating infections with antibiotics is important. Successful treatment of catheter infections has been reported in several groups of patients with malignant disease,14 even with home antibiotic therapy.15 In newborn babies the more usual practice
1302
is to remove the catheter.10 We need to know more about the treatment of catheter colonisation with antibiotics or antiseptics, and about changing (eg, over a guide wire) infected catheters, before these methods can be generally recommended. Removal is almost invariably required for tunnel infections,2 but local care can be effective for exit-site sepsis.16 Discussions about catheter sepsis are often hampered by problems of defining the condition. The most rigorous approach is to take blood simultaneously for quantitative culture from both the central venous catheter and a peripheral vein-higher colony counts’in the catheter sample would confirm the diagnosis of catheter sepsis.17 Since difficulties in obtaining a sample from either a peripheral vein or the catheter often hinder this approach, many researchers apply the principle that any unexplained signs of infection are catheter related. Such definitions encourage over-reporting of infections and can hinder comparisons. Tunnel and exit-site infections should be considered separately, because they are probably complications of insertion and fixation, respectively. For example2 -transparent plastic dressings are associated with higher rates of exit-site infection than are dry gauze dressings.18 Colonisation of the lumen probably results from lapses in techniques of catheter care and use: Puntis et apo showed that staff training, audit, and a strict protocol for catheter care can reduce
infection rates. Thrombosis may lead to occlusion of the catheter or to serious vascular complications.19 Routine screening of symptom-free patients is not rewarding,’9 but echocardiography can be helpful in patients with catheter malfunction, cardiopulmonary dysfunction, or sepsis.2° Catheter occlusion can be managed in most patients with thrombolytic agents,16,19 small volumes of dilute hydrochloric acid,21 or clearing with a guide wire;16 removal of the catheter may be necessary. Thrombi seldom require surgical remova119 although they seem to be especially troublesome in newborn babies.22 1. Essex-Cater A, Gilbert J, Robinson T, Littlewood JM. Totally implantable venous access systems in paediatric practice. Arch Dis Child 1989; 64: 119-23. 2. Ingram J, Weitzman S, Greenberg ML, Parkin P, Filler R. Complications of indwelling venous access lines in the pediatric hematology patient: a prospective comparison of external venous catheters and subcutaneous ports. Am J Pediatr Hematol Oncol 1991; 13: 130-36. 3. Ogata ES, Schulman S, Raffensberger J, Luck S, Rusnak M. Caval catheterisation in the intensive care nursery: a useful means for providing parenteral nutrition to the extremely low birth weight infant. J Pediatr Surg 1984; 19: 258-64. 4. Poole MA, Ross MN, Haase GM, Odom LF. Right atrial catheters in pediatric oncology: a patient/parent questionnaire study. Am J Pediatr Hematol Oncol 1991; 13: 152-55. 5. Halperin DL, Koren G, Attias D, Pellegrini E, Greenberg ML, Wyss M. Topical anesthesia for venous, subcutaneous drug reservoir and lumbar punctures in children. Pediatrics 1989; 84: 281-84. 6. Smith S, Dawson S, Hennessy R, Andrew M. Maintenance of the patency of indwelling central venous catheters: is heparin necessary? Am J Pediatr Hematol Oncol 1991; 13: 141-43. 7. Wiernowski JT, Elder-Thomley D, Dawson S, Rothney M, Smith S. Bacterial colonization of right atrial catheters in pediatric oncology: a
8.
comparison of sterile saline and bacteriostatic saline flush solutions. Am J Pediatr Hematol Oncol 1991; 13: 137-40. Puntis JWL. Percutaneous insertion of silastic central venous feeding
catheters. Intensive Ther Clin Monit 1987; 1: 7-10. 9. Goutail-Flaud MF, Sfez M, Berg A, Laguenie G, Couturier C, Barbotin-Larrieu F, Saint-Maurice C. Central venous catheter-related complications in newborns and infants: a 587 case survey. J Pediatr
Surg 1991; 26: 645-50. 10. Puntis JWL, Holden CE, Smallman S, Finkel Y, George RH, Booth IW. Staff training: a key factor in reducing intravascular catheter sepsis. Arch Dis Child 1991; 65: 335-37. 11. Wheeler RA, Griffiths DM, Burge DM. Retrograde tunnel: a method for the fixation of long-term paediatric central venous catheters. J Parent Enter Nutr 1991; 15: 114-15. 12. Grisoni ER, Mehta SK, Connors AF. Thrombosis and infection complicating central venous catheterization in neonates. J Pediatr Surg 1986; 21: 772-76. 13. King DR, Komer M, Hoffman J, Ginn-Pease ME, Stanley ME, Powell D, Harmel RP. Broviac catheter sepsis: the natural history of an iatrogenic infection. J Pediatr Surg 1985; 20: 728-33. 14. Olson
TA, Fischer GW, Lupo MC, Garcia VF, Maybee DA, Keiser J, Hartman KR. Antimicrobial therapy of Broviac catheter infections in pediatnc hematology oncology patients. J Pediatr Surg 1987; 22: 839-42. 15. Wiernowski JT, Rothney M, Dawson S, Andrew M. Evaluation of a home intravenous antibiotic program in pediatric oncology. Am J Pediatr Hematol Oncol 1991; 13: 144-47. 16. Dawson S, Pai MKR, Smith S, Rothney M, Ahmed K, Barr RD. Right atrial catheters in children with cancer: a decade of experience in the use of tunnelled, exteriorized devices at a single institution. Am J Pediatr Hematol Oncol 1991; 13: 126-29. 17. Balakrishnan G, Simpkins C, Greig M, Hallworth D. Catheter related sepsis. Prospective evaluation of catheter infection and catheter related sepsis in a paediatric intensive care unit. Br J Int Care 1991; 2: 17-23. 18. Conly JL, Grieves K, Peters B. A prospective randomised study comparing transparent and dry gauze dressings for central venous catheters. J Infect Dis 1989; 159: 310-19. 19. Ross P, Ehrenkrantz R, Kleinman CS, Seashore JH. Thrombus associated with central venous catheters in infants and children. J Pediatr Surg 1989; 24: 253-56. 20. O’Brodovich H, Adams M, Coates G, Way RC, Andrew M. Cardiopulmonary function during longterm central venous catheterization. Am J Pediatr Hematol Oncol 1991; 13: 148-51. 21. Duffy LF, Kerzner B, Gebus V, Dice J. Treatment of central venous catheter occlusion with hydrochloric acid. J Pediatr 1989; 114: 1002-04. 22. Berman W, Fripp RR, Yabek SM, Wernly J, Corlew S. Great vein and right atrial thrombus in critically ill patients and children with central venous lines. Chest 1991; 99: 963-67.
Colour
prejudice among pathologists
Important decisions based on colour perception are part of everyday life. Traffic signals outside the car and warning lights within have to be observed and interpreted correctly. It is not surprising that the transport industry in the UK has had legislation concerning the colour vision of its employees since the 1870s and that there is a legitimate community expectation that the highest standards of personal fitness and ability will be maintained in public transport or wherever an accident may have serious environmental consequences.1 By contrast, the colour perception of histopathologists, whose diagnostic decisions might have grave consequences, has received little or no scrutiny. Should the public be safeguarded from the colour-blind pathologist? Rigby and colleaguesz lately examined the colour perception of 30 histopathologists or cytopathologists by use of the Famsworth-Munsell 100-hue test. The basic ingredients of this test are 85 colour samples
found. The authors continue "During this manic phase he came across a piece of fabric with a picture of Jerusalem on it. He wanted to hide this in a safe place and immediately thought of doing so behind a painting hanging on the wall in the sitting room. When he moved the painting to push the cloth behind it, a large envelope containing the missing L3000 fell to the floor." What is not clear is whether the hiding place was rediscovered because the patient’s mood was the same, or because he found himself again wanting to hide something valuable. If the events are ever repeated, perhaps the doctor should encourage the patient to hide a further c3000 during his normal mood state, in which case the original C3000 might be recovered without waiting for a recurrence of the mania. It is not surprising that recall is best for memories that are relevant to the person’s current circumstances and to whatever he or she is doing and feeling at the time. It would not have been adaptive for our hunter-gatherer ancestors if their minds had been occupied with memories of hunting while they were gathering, or with memories of gathering while they were hunting-unless, of course, the hunting or gathering was going badly. If that was the case they might well have switched from the pursuit of one goal to the pursuit of another, and when motivation changes, memory, along with most other mental functions, is likely to be affected.7,8Thus scuba divers who are frustrated with scuba diving might well have better recall for information about water skiing than about scuba diving, whether the new information is presented under water or in the classroom.
mania, that the as
1. Godden
money
was
follows:
D, Baddely AD. Context-dependent
memory in two natural
environments. Br J Pschol 1975; 71: 99-104 2. Goodwin DW, Powell B, Bremer D. Alcohol and recall: state dependent effects in man. Science 1968; 163: 1358-60. 3. Eich JE. The cue-dependent nature of state-dependent retrieval. Mem
Cogn 1980; 8: 157-73. 4. Raush HL, Barry WA, Hertel RK, Swain MA. Communication, conflict and marriage. San Francisco: Jossey-Bass, 1974. 5. Gray P. Psychology. New York: Worth, 1991. 6. Williams JMG, Markar HR. Money hidden and rediscovered in subsequent manic phases: a case of action dependent mood state? Br J Psychiatry 1991; 159: 579-81. 7. Toates FM. Models of motivation. In: Toates FM, Halliday TR, eds. Animal behaviour. Vol 1, causes and effects. Oxford: Blackwell, 1983. 8. Klinger E. Consequences of commitment to and disengagement from incentives. Psychol Rev 1975; 82: 1-25.
Central
venous access
in children
Central venous catheters have many applications in children. The indications are commonest
chemotherapy
of
disease and total parenteral nutrition; children with other conditions requiring intermittent courses of treatment (eg, cystic fibrosis, haemophilia, and thalassaemia) may likewise benefit from this approach.l The central vein may be entered directly, either surgically or percutaneously, or indirectly via a peripheral vein; the catheter tip
malignant
should lie in the superior vena cavaz or the right atrium.3 In oncology, subcutaneous venous access reservoirs (eg, ’Portacath’, ’Mediport’) or tunnelled lines with a subcutaneous cuff for fixation and an external connection (eg, ’Hickman’, ’Broviac’) are commonly used. A questionnaire study4 of parents’ and patients’ reactions showed that after one year 95% of patients with subcutaneous devices were satisfied, as were 97% with external devices. Only 16% of patients were unhappy that a needle is required to gain access to a subcutaneous device (use of a topical anaesthetic before needle puncture can help in this respects) and only 3% of those with external devices found the need for regular flushing troublesome. Although both types of access are suitable for intermittent use, subcutaneous devices are not so suitable for long-term, continuous intravenous treatment because the skin over the reservoir may ulcerate. Patients can ignore the presence of the subcutaneous device when it is not in use, whereas external catheters require regular dressing and flushing. Nevertheless, the flushing procedure can be simplified, since weekly flushing with saline6 or, preferably, a bacteriostatic solutionis as satisfactory as
daily flushing with an anticoagulant.
Selection of method of access is likewise important in patients requiring long-term intravenous nutrition, especially in newborn babies. Broviac-type catheters are valuable, but they require surgical insertion into a central vein, which may subsequently become occluded. If catheters have to be removed because of infection or mechanical complications, it may become increasing difficult to find veins of adequate calibre. Fine silastic catheters inserted via a peripheral vein8,9 can overcome this difficulty. These catheters are most successful if used exclusively for parenteral nutrition, with the line being breached no more than once daily When peripheral venous access is impossible or the central venous line is required for multiple uses, the wider calibre Broviac-type catheter (or possibly, in larger infants and children, a multilumen catheter) is more
appropriate.
Silastic
is
the
most popular material but less prone to thrombus be polyurethane may formation and sepsis.11 One report9 suggested that the tip of polyurethane catheters is harder than silastic and therefore such catheters would not be appropriate for newborn babies. Catheters can become dislodged despite the subcutaneous cuff ;2 a new design of polyurethane device may help in this respect." Higher rates of catheter infection have been recorded in newborn babies than in older children. 12,13 Because of difficulties with peripheral, and even repeated central, venous access in this age group, the possibility of treating infections with antibiotics is important. Successful treatment of catheter infections has been reported in several groups of patients with malignant disease,14 even with home antibiotic therapy.15 In newborn babies the more usual practice
1302
is to remove the catheter.10 We need to know more about the treatment of catheter colonisation with antibiotics or antiseptics, and about changing (eg, over a guide wire) infected catheters, before these methods can be generally recommended. Removal is almost invariably required for tunnel infections,2 but local care can be effective for exit-site sepsis.16 Discussions about catheter sepsis are often hampered by problems of defining the condition. The most rigorous approach is to take blood simultaneously for quantitative culture from both the central venous catheter and a peripheral vein-higher colony counts’in the catheter sample would confirm the diagnosis of catheter sepsis.17 Since difficulties in obtaining a sample from either a peripheral vein or the catheter often hinder this approach, many researchers apply the principle that any unexplained signs of infection are catheter related. Such definitions encourage over-reporting of infections and can hinder comparisons. Tunnel and exit-site infections should be considered separately, because they are probably complications of insertion and fixation, respectively. For example2 -transparent plastic dressings are associated with higher rates of exit-site infection than are dry gauze dressings.18 Colonisation of the lumen probably results from lapses in techniques of catheter care and use: Puntis et apo showed that staff training, audit, and a strict protocol for catheter care can reduce
infection rates. Thrombosis may lead to occlusion of the catheter or to serious vascular complications.19 Routine screening of symptom-free patients is not rewarding,’9 but echocardiography can be helpful in patients with catheter malfunction, cardiopulmonary dysfunction, or sepsis.2° Catheter occlusion can be managed in most patients with thrombolytic agents,16,19 small volumes of dilute hydrochloric acid,21 or clearing with a guide wire;16 removal of the catheter may be necessary. Thrombi seldom require surgical remova119 although they seem to be especially troublesome in newborn babies.22 1. Essex-Cater A, Gilbert J, Robinson T, Littlewood JM. Totally implantable venous access systems in paediatric practice. Arch Dis Child 1989; 64: 119-23. 2. Ingram J, Weitzman S, Greenberg ML, Parkin P, Filler R. Complications of indwelling venous access lines in the pediatric hematology patient: a prospective comparison of external venous catheters and subcutaneous ports. Am J Pediatr Hematol Oncol 1991; 13: 130-36. 3. Ogata ES, Schulman S, Raffensberger J, Luck S, Rusnak M. Caval catheterisation in the intensive care nursery: a useful means for providing parenteral nutrition to the extremely low birth weight infant. J Pediatr Surg 1984; 19: 258-64. 4. Poole MA, Ross MN, Haase GM, Odom LF. Right atrial catheters in pediatric oncology: a patient/parent questionnaire study. Am J Pediatr Hematol Oncol 1991; 13: 152-55. 5. Halperin DL, Koren G, Attias D, Pellegrini E, Greenberg ML, Wyss M. Topical anesthesia for venous, subcutaneous drug reservoir and lumbar punctures in children. Pediatrics 1989; 84: 281-84. 6. Smith S, Dawson S, Hennessy R, Andrew M. Maintenance of the patency of indwelling central venous catheters: is heparin necessary? Am J Pediatr Hematol Oncol 1991; 13: 141-43. 7. Wiernowski JT, Elder-Thomley D, Dawson S, Rothney M, Smith S. Bacterial colonization of right atrial catheters in pediatric oncology: a
8.
comparison of sterile saline and bacteriostatic saline flush solutions. Am J Pediatr Hematol Oncol 1991; 13: 137-40. Puntis JWL. Percutaneous insertion of silastic central venous feeding
catheters. Intensive Ther Clin Monit 1987; 1: 7-10. 9. Goutail-Flaud MF, Sfez M, Berg A, Laguenie G, Couturier C, Barbotin-Larrieu F, Saint-Maurice C. Central venous catheter-related complications in newborns and infants: a 587 case survey. J Pediatr
Surg 1991; 26: 645-50. 10. Puntis JWL, Holden CE, Smallman S, Finkel Y, George RH, Booth IW. Staff training: a key factor in reducing intravascular catheter sepsis. Arch Dis Child 1991; 65: 335-37. 11. Wheeler RA, Griffiths DM, Burge DM. Retrograde tunnel: a method for the fixation of long-term paediatric central venous catheters. J Parent Enter Nutr 1991; 15: 114-15. 12. Grisoni ER, Mehta SK, Connors AF. Thrombosis and infection complicating central venous catheterization in neonates. J Pediatr Surg 1986; 21: 772-76. 13. King DR, Komer M, Hoffman J, Ginn-Pease ME, Stanley ME, Powell D, Harmel RP. Broviac catheter sepsis: the natural history of an iatrogenic infection. J Pediatr Surg 1985; 20: 728-33. 14. Olson
TA, Fischer GW, Lupo MC, Garcia VF, Maybee DA, Keiser J, Hartman KR. Antimicrobial therapy of Broviac catheter infections in pediatnc hematology oncology patients. J Pediatr Surg 1987; 22: 839-42. 15. Wiernowski JT, Rothney M, Dawson S, Andrew M. Evaluation of a home intravenous antibiotic program in pediatric oncology. Am J Pediatr Hematol Oncol 1991; 13: 144-47. 16. Dawson S, Pai MKR, Smith S, Rothney M, Ahmed K, Barr RD. Right atrial catheters in children with cancer: a decade of experience in the use of tunnelled, exteriorized devices at a single institution. Am J Pediatr Hematol Oncol 1991; 13: 126-29. 17. Balakrishnan G, Simpkins C, Greig M, Hallworth D. Catheter related sepsis. Prospective evaluation of catheter infection and catheter related sepsis in a paediatric intensive care unit. Br J Int Care 1991; 2: 17-23. 18. Conly JL, Grieves K, Peters B. A prospective randomised study comparing transparent and dry gauze dressings for central venous catheters. J Infect Dis 1989; 159: 310-19. 19. Ross P, Ehrenkrantz R, Kleinman CS, Seashore JH. Thrombus associated with central venous catheters in infants and children. J Pediatr Surg 1989; 24: 253-56. 20. O’Brodovich H, Adams M, Coates G, Way RC, Andrew M. Cardiopulmonary function during longterm central venous catheterization. Am J Pediatr Hematol Oncol 1991; 13: 148-51. 21. Duffy LF, Kerzner B, Gebus V, Dice J. Treatment of central venous catheter occlusion with hydrochloric acid. J Pediatr 1989; 114: 1002-04. 22. Berman W, Fripp RR, Yabek SM, Wernly J, Corlew S. Great vein and right atrial thrombus in critically ill patients and children with central venous lines. Chest 1991; 99: 963-67.
Colour
prejudice among pathologists
Important decisions based on colour perception are part of everyday life. Traffic signals outside the car and warning lights within have to be observed and interpreted correctly. It is not surprising that the transport industry in the UK has had legislation concerning the colour vision of its employees since the 1870s and that there is a legitimate community expectation that the highest standards of personal fitness and ability will be maintained in public transport or wherever an accident may have serious environmental consequences.1 By contrast, the colour perception of histopathologists, whose diagnostic decisions might have grave consequences, has received little or no scrutiny. Should the public be safeguarded from the colour-blind pathologist? Rigby and colleaguesz lately examined the colour perception of 30 histopathologists or cytopathologists by use of the Famsworth-Munsell 100-hue test. The basic ingredients of this test are 85 colour samples
