330 Archives ofDisease in Childhood 1990; 65: 330-332
Peak expiratory flow rate and the acute chest Arch Dis Child: first published as 10.1136/adc.66.3.330 on 1 March 1991. Downloaded from syndrome in homozygous sickle cell disease
E Frances Bowen, Jonathan G Crowston, Karel De Ceulaer, Graham R Serjeant
Abstract aged from 8-16 years. The diagnosis of SS dis- The peak expiratory flow rate (PEFR) was ease was based on standard critiera. studied in 20 matched pairs of children with The acute chest syndrome was defined as homozygous sickle cell disease with either no acute pulmonary symptoms associated with episodes or six or more episodes of acute either clinical signs of parenchymal involvement chest syndrome. The pairs were carefully or pulmonary infiltrates on radiography. The matched for height and a highly significant frequency of these events was derived by review reduction in PEFR was observed in children of the computerised clinical codings and con- with multiple episodes of acute chest syn- firmed by examination of patient records. Chil- drome. Lateral and anteroposterior chest dia- dren with asthma, bronchitis, and who had suf- meters and chest circumference correlated fered a stroke were excluded. If two events were with PEFR but did not differ between index separated by less than four weeks the records and control cases. The most likely cause of were reviewed to distinguish a prolonged single the reduced PEFR in children with multiple event from two separate events. The number of episodes of acute chest syndrome is an accu- episodes of acute chest syndrome varied from mulating pulmonary fibrosis that decreases nil to 16 and 31 subjects had had six episodes or lung compliance. more (fig 1). Of these 31 subjects, three had chronic disease possibly influencing lung func- tion (systemic lupus erythematosus, nephrotic Children with homozygous sickle cell (SS) dis- syndrome, and recurrent sepsis) and were ease are prone to the acute chest syndrome, the excluded and three had defaulted leaving 25 relative risk being four times that in normal cases. It was possible to match 20 of these index controls by the age of 4 years.1 The term acute cases with 20 children who had never had acute chest syndrome covers a range of acute pulmon- chest syndrome (control group). Each pair was ary episodes including infection, infarction, and matched for sex, height, and age (in order of sequestration within the pulmonary capillaries. priority). Adults with SS disease have significant reduc- Height was measured, without shoes, with a http://adc.bmj.com/ tions in total lung capacity, vital capacity, Harpenden wall mounted stadiometer or a por- forced vital capacity, and ratio of residual table stadiometer (checked against the fixed volume to total lung capacity.2 3 Furthermore model) for home visits. Anteroposterior and the diffusing capacity of the alveolar membrane lateral chest diameters were measured with Har- is reduced,2 4 the greatest reductions occurring penden chest calipers in the horizontal plane in those with a history of pulmonary through the fourth sternocostal junction at the complications.2 Peak expiratory flow rate end of normal expiration. Chest circumference on September 24, 2021 by guest. Protected copyright. (PEFR), which might be expected to fall with was measured at the same level and stage of decreased lung compliance after pulmonary expiration with a standard tape measure. PEFR complications, was normal in a small study of 12 was measured with a portable peak flow meter SS children and 12 controls aged 7-19 years.5 To determine whether peak expiratory flow rate is affected by a history of pulmonary complica- 50 tions, the PEFR has been studied in 20 matched pairs with SS disease, with and without histories of pulmonary complications. 40-
Patients and methods 30o Medical Research The patients attended the sickle cell clinic of the 0 Council Laboratories 0 University Hospital of the West Indies, Kings- 7 (Jamaica), 20- University of the ton, Jamaica, and were participating in a cohort West Indies, study of sickle cell disease from birth. Between Kingston 7, June 1973 and December 1981, 100 000 con- Jamaica 10 E Frances Bowen secutive normal deliveries at the main govern- Jonathan G Crowston ment maternity hospital (Victoria Jubilee Hos- Karel De Ceulaer pital) were screened. A total of 314 babies with Graham R Serjeant 0 SS disease were detected and they have been fol- 0 1 2 3 4 5 6 7 8 9 10\11'12'131415 16 Correspondence and requests No of episodes of acute chest syndrome for reprints to: lowed up prospectively. Of these 55 have died Professor Serjeant. and 31 have emigrated, leaving 228 children at Figure I Frequency distribution ofepisodes ofacute chest Accepted 6 September 1990 the study date (December 1989/January 1990) syndrome in children with SS disease. Peak expiratoryflow rate and the acute chest syndrome in homozygous sickle cell disease 331
(Mini-Wright, Airmed, Clement-Clarke Inter- cases (mean (SD) 14-7 (1-5) cm) and controls national) in the standing position and taking the (14-6 (1-3) cm). Lateral chest diameters varied
maximum offive successive measurements. The from 16-6-24-6 cm and also did not vary Arch Dis Child: first published as 10.1136/adc.66.3.330 on 1 March 1991. Downloaded from instrument was not independently calibrated between index cases (20-2 (1-8)) and controls but the same instrument was used for the com- (20-6 (1-9)). Both measurements correlated with plete study. No other aspect of pulmonary func- PEFR (figs 3 and 4), although the correlation tion was measured. was closer with lateral diameter (r=0-69, The paired Student's t test was used to com- p
600. 600
500- 0
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LU X. 300- 0c _ % * r=0-66 r = 0-69 X~~~~ * p IinnWu .1 50 go 70 80 16 18 20 22 24 Chest circumference (cm) Lateral chest diameter (cm) Figure 2 Association between PEFR and chest Figure 4 Association between PEFR and lateral chest circumference. diameter. 600- 600- 0 Index 500' a r= 0-43 0 Contr p E 400' 0 L 400' 0 0 80 w c3 0a S 300' 00 o J* S 0 CL300- 0@ a I. .10 0 . 0 .3 * S 0 200 200' 0 1W0 I LI , . .. 12 14 16 18 20 110 120 130 140 150 160 170 Anteroposterior chest diameter (cm) Height (cm) Figure 3 Association between PEFR and anteroposterior Figure S Association betveen PEFR and height in index chest diameter. and control children. 332 Bowen, Crowston, De Ceulaer, Serjeant range 200-400 1/min) was significantly less than diameters of the chest, chest circumference, in controls (mean 355 (57), 230-500 1/min). or anteroposterior/lateral chest diameter ratio. To ascertain whether PEFR showed progres- All dimensions correlated significantly with Arch Dis Child: first published as 10.1136/adc.66.3.330 on 1 March 1991. Downloaded from sive deterioration with the number or severity of PEFR, the closest correlation occurring with episodes of acute chest syndrome, an analysis of lateral chest diameter and circumference. There covariance was conducted between PEFR, was no correlation between PEFR and height, number of episodes of acute chest syn- anteroposterior/lateral chest diameter ratio. droe or severity of such episodes depicted as the Furthermore as the ratio did not differ between number requiring hospital admission or transfu- index and control cases, this suggests that the sion treatment. The analysis showed no signifi- abnormal chest shape in SS disease does not cant effect on PEFR of either the number or result from, or predispose to, multiple episodes severity of episodes of acute chest syndrome. of acute chest syndrome. As these physical indices of chest shape or size did not differ between the study groups, Discussion one must conclude that chronic pulmonary Recurrent respiratory infections were noted in changes consequent on the acute chest syn- the first case report of sickle cell disease7 and drome contribute to the observed differences in the susceptibility of children with SS disease to PEFR. The pathological mechanism of this serious pulmonary disease has since been well reduced PEFR is conjectural but parenchymal documented.' 8 Abnormalities of lung volume scarring presumed to result from local infarc- and function have been reported in SS disease, tion and alveolar necrosis has been observed at although it is unclear the extent to which these necropsy. 12 Such damage would be expected to changes reflect the abnormal chest shape of SS be cumulative and to increase with each episode disease or histories of pulmonary complications. of acute chest syndrome, but there was no evi- An earlier Jamaican study had shown that the dence of deteriorating PEFR with increasing diffusing capacity of the alveolar membrane was episodes of six and above. It is still possible that reduced in SS disease and was decreased further cumulative damage would be demonstrable in in patients with a history of pulmonary patients with fewer episodes (one to five) or that complications.2 the severity of the attack rather than the overall The PEFR is a simple test of lung function number of episodes is the major determinant of amenable to population studies and domiciliary a reduced PEFR in these children. use. The Mini-Wright peak flow meter is cheap and provides a single reproducible measure- EF Bowen was supported by grants from the Medical Research Council Rogers Award, the Royal College of Pathologists, and ment.9 The major determinants of PEFR are the British Medical and Dental Students' Trust. JG Crowston the static recoil pressure of the lungs and air- was supported by grants from the Medical Research Council Rogers Award, and the British Medical and Dental Students' ways resistance.10 As the airways resistance in Trust. We thank Miss Joanne Morris for assistance with the sta- SS disease has been shown to be normal,4 11 tistical tests. abnormal values for PEFR are likely to result from changes in lung compliance. http://adc.bmj.com/ 1 De Ceulaer K, McMullen KW, Maude GH, Keatinge R, The only previous published study on PEFR Serjeant GR. Pneumonia in young children with homo- in SS disease failed to show a difference between zygous sickle cell disease: risk and clinical features. Eur J7 Pediatr 1985;144:255-8. SS patients and normal controls,5 but the study 2 Miller GJ, Serjeant GR. An assessment of lung volumes and was small and only four out of 12 SS patients gas transfer in sickle cell anaemia. Thorax 1971;26:309-15. 3 Miller GJ, Serjeant GR, Saunders MJ, Richardson C, Gilson had had previous pulmonary complications RJC. Interpretation of lung function tests in the sickle-cell (three with one episode and one with three epi- haemoglobinopathies. Thorax 1978;33:85-8. 4 Femi-Pearse D, Gazioglu KM, Yu PN. Pulmonary function on September 24, 2021 by guest. Protected copyright. sodes). studies in sickle cell disease. J Appl Physiol 1970;28:574-7. The present study has shown that when 5 Wall MA, Platt OS, Strieder DJ. Lung function in children with sickle cell anemia. Am Rev RespirDis 1979;120:210-4. populations are selected according to an absence 6 Godfrey S, Kamburoff PL, Nairn JR. Spirometry, lung of acute pulmonary episodes or six or more epi- volumes and airway resistance in normal children aged 5 to 18 years. Br J7 Dis Chest 1970;64:15-24. sodes, highly significant differences in PEFR 7 Herrick J. Peculiar elongation and sickle shaped red blood between the groups emerge. In children height corpuscles in a case of severe anemia. Arch Intern Med 1910; 6:517-21. appears to be a major determinant of PEFR,6 8 Barrett-Connor E. Acute pulmonary disease and sickle cell but pairs were matched so that the mean differ- anemia. Am Rev Respir Dis 1971;104:159-65. 9 Wright BM, McKerrow CB. Maximum forced expiratory ence between index cases and controls was only flow rate as a measure of ventilatory capacity. With a 0 9 cm. It was also possible that differences in description of a new portable instrument for measuring it. BMJ 1959;ii:1041. chest dimensions or shape were associated with 10 Mead J, Turner J, Machler R, Little J. Significance of the a proneness to acute pulmonary episodes and relationship between lung recoil and maximum expiratory flow. J Appl Physiol 1967;22:95-108. could have contributed to the difference in 11 Young RC, Rachal RE, Reindorf CA, et al. Lung function in PEFR. However, analysis showed that there sickle cell hemoglobinopathy patients compared with healthy subjects. J Nadl Med Assoc 1989;80:509-14. were no significant differences between index 12 Haupt HM, Moore GW, Bauer TW, Hutchins GM. The lung and control cases in anteroposterior or lateral in sickle cell disease. Chest 1982;81:332-7.