Emergency triage assessment for hypoxaemia in neonates and young children in a Kenyan hospital: an observational study

263Bull World Health Organ 2009;87:263–270 | doi:10.2471/BLT.07.049148 Emergency triage assessment for hypoxaemia in neonates and young children in a Kenyan hospital: an observational study Michael K Mwaniki,a D James Nokes,a James Ignas,a Patrick Munywoki,a Mwanajuma Ngama,a Charles RJC Newton,a Kathryn Maitland a & James A Berkley a Objective To describe the prevalence of hypoxaemia in children admitted to a hospital in Kenya for the purpose of identifying clinical signs of hypoxaemia for emergency triage assessment, and to test the hypothesis that such signs lead to correct identification of hypoxaemia in children, irrespective of their diagnosis. Methods From 2002 to 2005 we prospectively collected clinical data and pulse oximetry measurements for all paediatric admissions to Kilifi District Hospital, Kenya, irrespective of diagnosis, and assessed the prevalence of hypoxaemia in relation to the WHO clinical syndromes of “pneumonia” on admission and the final diagnoses made at discharge. We used the data collected over the first three years to derive signs predictive of hypoxaemia, and data from the fourth year to validate those signs. Findings Hypoxemia was found in 977 of 15 289 (6.4%) of all admissions (5% to 19% depending on age group) and was strongly associated with inpatient mortality (age-adjusted risk ratio: 4.5; 95% confidence interval, CI: 3.8–5.3). Although most hypoxaemic children aged ³ 60 days met the WHO criteria for a syndrome of “pneumonia” on admission, only 215 of the 693 (31%) such children had a final diagnosis of lower respiratory tract infection (LRTI). The most predictive signs for hypoxaemia included shock, a heart rate < 80 beats per minute, irregular breathing, a respiratory rate > 60 breaths per minute and impaired consciousness. However, 5–15% of the children who had hypoxaemia on admission were missed, and 18% of the children were incorrectly identified as hypoxaemic. Conclusion The syndromes of pneumonia make it possible to identify most hypoxaemic children, including those without LRTI. Shock, bradycardia and irregular breathing are important predictive signs, and severe malaria with respiratory distress is a common cause of hypoxaemia. Overall, however, clinical signs are poor predictors of hypoxaemia, and using pulse oximetry in resource-poor health facilities to target oxygen therapy is likely to save costs. Une traduction en français de ce résumé figure à la fin de l’article. Al final del artículo se facilita una traducción al español. .ةلاقلما هذهل لماكلا صنلا ةياهن في ةصلاخلا هذهل ةيبرعلا ةمجترلا a Centre for Geographic Medicine Research, Kenya Medical Research Institute, PO Box 230, Kilifi, 80108, Kenya. Correspondence to Michael Mwaniki (e-mail: mmwaniki@kilifi.kemri-wellcome.org). (Submitted: 1 November 2007 – Revised version received: 24 June 2008 – Accepted: 4 August 2008 – Published online: 13 February 2009 ) Introduction Recognizing and correcting poor oxygenation early is an es- sential aspect of paediatric emergency care. The management of hypoxaemia includes establishing an open airway and alveolar ventilation, providing supplemental oxygen, restoring circulation and treating the underlying cause. Hypoxaemia correlates with mortality,1 and early assessment and prompt oxygen therapy probably improve survival.2,3 In developing countries, bottled oxygen is expensive and commonly in short supply. However, most hospitals providing secondary care cannot perform pulse oximetry or measure arte- rial oxygen concentration to properly target oxygen delivery. Furthermore, clinical assessment is often carried out by rela- tively inexperienced health workers, as a result of which simple algorithms for identifying hypoxaemia have been developed and studied. However, the studies have been conducted almost entirely among children with lower respiratory tract infection (LRTI),4–9 and little prospective validation has been performed. Certain clinical signs have been identified as predictive of hypoxaemia: a fast respiratory rate for age, lower chest wall indrawing, grunting, head nodding, cyanosis, the absence of crying during the examination, and the inability to breastfeed or drink. No single sign is a reliable predictor, and sensitivity is generally low for any single sign.10 WHO currently recom- mends giving oxygen urgently to children with cyanosis, signs of shock, severe respiratory distress, the syndrome of “very severe pneumonia” or a respiratory rate of 70 breaths per minute (min) or more.11 Given the paucity of data outside the context of LRTI, we first aimed to describe the prevalence of hypoxaemia in relation to the WHO clinical syndromes of “pneumonia” at admission and the final diagnoses made at discharge. We then tested the hypothesis that hypoxaemia could be identified on the basis of clinical signs by studying a large population of children consecutively admitted to a rural, Kenyan district hospital, irrespective of their diagnosis. We report findings from 15 289 children and neonates admitted during a 3-year period and validate our findings using data from 4695 admissions over a fourth year. Methods Study setting Since 1998 we have conducted continuous inpatient surveil- lance to describe the causes and clinical features of common illnesses among children admitted to Kilifi District Hospital in Kenya.12,13 The hospital is located at sea level in an area with endemic malaria. Government-employed clinical officers not involved in research refer children to the paediatric ward 264 Bull World Health Organ 2009;87:263–270 | doi:10.2471/BLT.07.049148 Research Emergency triage for hypoxaemia in Kenyan children Michael K Mwaniki et al. (40 beds) or the high-dependency unit (6 beds). On admission, discharge or death, standardized clinical and labora- tory data are collected by clinical officers, who in Kenya receive 3 years of basic medical training, or by fully trained medical officers with less than 5 years of paediatric experience.12,13 For this analy- sis, we used data collected at admission from January 2002 to December 2005 and final discharge diagnosis for each consecutive admission over the same period of time. The Kenyan National Scientific and Ethical Review Boards and the Coventry Research Ethics Commit- tee approved the study. Clinical definitions WHO defines a set of clinical syn- dromes of “pneumonia” on the basis of clinical history and clinical signs at presentation for the purpose of deter- mining the need for admission and the type of antibiotic treatment required.11,14 The definitions have high sensitivity with respect to LRTI, but they lack specificity. The “syndrome of pneu- monia” is defined as a history of cough or difficulty breathing plus an elevated respiratory rate for age (if < 2 months, ³ 60 breaths per min; if 2–11 months, ³ 50 breaths per min; and if 1–5 years, ³ 40 breaths per min), and no signs of severe pneumonia syndrome. “Severe pneumonia syndrome” is defined as a history of cough or difficulty breath- ing plus lower chest wall indrawing or nasal flaring and no signs of very severe pneumonia syndrome. “Very severe pneumonia syndrome” is defined as cough or difficulty breathing plus any of the following signs: cyanosis, inabil- ity to drink or breastfeed, convulsions, lethargy or unconsciousness. Regarding signs not included in the above definitions, prostration was defined as the inability to sit unsup- ported for a child ³ 9 months of age, or the inability to breastfeed or drink for a child < 9 months of age. Level of consciousness was assessed using the Blantyre coma scale.15 Shock was defined as the presence of any one of the following signs: capillary refill de- layed for > 3 seconds (s), a noticeable temperature gradient or a weak pulse volume. For this analysis, we defined severe anaemia as a haemoglobin con- centration £ 4 g/dl. Malaria screening was performed on every admission with thick and thin blood films stained and examined by standard techniques. Oxygen saturation (SaO2) was mea- sured at admission by trained clinical assistants using fingertip pulse oximetry (Nellcor Puritan Bennett NPB-40, United States of America). We de- fined hypoxaemia as an SaO2 < 90%. Bottled oxygen was always available for hypoxaemic children. LRTI and other conditions were managed according to current WHO guidelines.11 All final diagnoses, including LRTI, were made prospectively by the discharging clini- cian after a review of admission history, inpatient management notes and all available laboratory and radiologic tests. For this analysis, we first used the WHO pneumonia syndromes to clas- sify children according to the clinical findings observed at admission. We then examined up to two final diagnoses recorded at discharge or death using all available clinical, laboratory and radio- logical information. Thus, the sum of all final diagnoses may exceed 100%. Statistical methods At the point of contact, clinical data were entered into a FileMaker Pro database 5.5v1 (FileMaker Inc., USA). Laboratory data were double entered and verified using FoxPro 2.5b for Win- dows (Microsoft Corporation, Seattle, WA, USA). Stata version 9.2 (Stata Corp, College Station, TX, USA) was used for the final analysis. We split the data into a 3-year derivation set and a 1-year validation set. We divided admissions into three age groups because we hypothesized that the prevalence, causes and predic- tors of hypoxaemia could differ among neonates, young infants and older children. We first determined the preva- lence of hypoxaemia in all age groups. We then examined hypoxaemia in rela- tion to the WHO clinical syndromes of pneumonia at admission and final diagnosis at discharge. After excluding children in whom oximetry was not performed or with a failed oximeter reading or who had known cardiac dis- ease or asthma, we developed predictive models of hypoxaemia in three stages by means of likelihood ratios (LRs). The LR indicates the degree to which a positive or negative result increases or lowers, respectively, the odds of having the disease in question (hypoxaemia in this case). LRs change less under the influence of disease prevalence than sensitivity and specificity, and they may be calculated for multiple test results.16 For each putative clinical sign used to predict hypoxaemia, we first calculated the crude LR for a positive result and for a negative result. Signs with crude LR ³ 2.0 or £ 0.5 were considered clini- cally useful. We then used the method of Speigelhalter and Knill-Jones to adjust for the confounding effects of related variables, as determined by multivariate analyses, in four separate groups: respi- ratory, cardiovascular, neurological and general signs.13,17,18 In the third step, we constructed practical prediction rules for hypoxaemia using signs with adjusted likelihood ratios of ³ 2.0 or £ 0.5, pri- oritized by strength of prediction and clinical practicability. We finally evalu- ated the final rules using the area under the receiver operating characteristic (ROC) curves using the validation data set. Distributions of age were compared by means of the Wilcoxon rank sum test. Results Between 2002 and 2004, 15 401 chil- dren were admitted (derivation set) to the hospital. Of these children, 13 183 were aged ³ 60 days; 991 were aged 7–59 days, and 1115 were aged < 7 days. Excluded from the study were 112 children: 35 without pulse oximetry results; 59 with known cardiac disease and 18 with known asthma. Characteristics Admissions aged ³ 60 days Among the 13 183 children admit- ted, the proportion of males was 56% and the median age was 32 months (interquartile range: 11–42). The most common final diagnoses were malaria (4982, or 38%), LRTI (2869, or 22%), gastroenteritis (2026, or 15%), mal- nutrition (1261, or 10%) and severe anaemia (717, or 5%). Hypoxaemia was found in 693 (5.3%) of the children admitted. The median age of the children with and without hypoxaemia was 18.9 and 22.9 months, respectively (P = 0.036). The most frequent final diagnoses among hypoxaemic children were malaria (244, or 35%), LRTI (221, or 32%), malnu- trition (68, or 10%) and gastroenteritis (49, or 7%). Severe anaemia was found in 30 children (< 1%). Overall, 753 (6%) children died, including 150 of the 693 (22%) with hypoxaemia. Irrespective of the final clinical diagnosis, hypoxaemia was strongly associated with inpatient 265Bull World Health Organ 2009;87:263–270 | doi:10.2471/BLT.07.049148 Research Emergency triage for hypoxaemia in Kenyan childrenMichael K Mwaniki et al. death (age-adjusted risk ratio, RR: 4.5; 95% confidence interval, CI: 3.8–5.3). Very severe pneumonia syndrome Of the children admitted, 2525 (19%) satisfied the WHO criteria for very severe pneumonia: 291 (12%) of these children were hypoxaemic and 287 (11%) died. The final diagnoses in- cluded severe malaria (1268, or 50%), LRTI (514, or 20%), gastroenteritis (185, 7%), acute febrile convulsion of unknown cause (without malaria, meningitis or epilepsy) (181, or 7%), malnutrition (173, or 7%), meningitis (75, or 3%) and severe anaemia (56, or 2%). In 86 (3%) children, both malaria and LRTI were present. Of the 291 hypoxaemic children, 119 (41%) had a final diagnosis of malaria and 82 (28%), of LRTI. The case fatality rate among hypoxaemic children was 30% (89/291). Severe pneumonia syndrome Of the children admitted, 2267 (17%) satisfied the WHO criteria for severe pneumonia, 156 (7%) were hypoxaemic and 107 (5%) died. The final diagnoses included LRTI (1654, or 73%), malaria (349, or 15%), malnutrition (180, or 8%), gastroenteritis (49, or 2%) and severe anaemia (43, or 2%). A further 155 (7%) children had both malaria and LRTI. Of the 156 hypoxaemic children, 113 (72%) had a final diagno- sis of LRTI and 18 (12%), of malaria. The case fatality rate was 16% (25/156) among children who were hypoxaemic. Pneumonia syndrome Of the children admitted, 697 (5%) satisfied the WHO criteria for pneu- monia, and of this group, 14 (2%) were hypoxaemic and 33 (5%) died. Frequent final diagnoses among these children were malaria (245, or 35%), LRTI (197, or 28%), malnutrition (93, or 13%), gastroenteritis (76, or 11%) and severe anaemia (26, or 4%). Of the 14 hypoxaemic children, 8 (57%) had a final diagnosis of malaria and 4 (29%), of LRTI. The case fatality rate was 21% (3/14) among children who were hypoxaemic. Overall, 461 of 693 (67%) hypox- aemic children who were admitted met the clinical criteria for one of the WHO pneumonia syndromes, and 215 of 693 (31%) of the hypoxaemic children admitted had a final discharge diagnosis of LRTI (Fig. 1). Fig. 1. Distribution of LRTI and hypoxaemic cases across the WHO “pneumonia” syndromes “very severe” 2525 WHO “pneumonia syndromes” Final discharge diagnosis LRTI 514 Admissions 13 183 Others 2011 Hypoxaemic 82 (16%) Hypoxaemic 209 (10%) “severe” 2267 LRTI 1654 Others 613 Hypoxaemic 113 (7%) Hypoxaemic 43 (7%) “pneumonia” 697 LRTI 197 Others 500 Hypoxaemic 4 (2%) Hypoxaemic 10 (2%) “no pneumonia” 7694 LRTI 480 Others 7214 Hypoxaemic 16 (3%) Hypoxaemic 216 (3%) LRTI, lower respiratory tract infection. Admissions aged 7–59 days Of the 991 children aged 7–59 days who were admitted (57% males) 78 (8%) were hypoxaemic and 82 (8%) died. The main final diagnoses were neo- natal sepsis (497, or 50%); LRTI (301, or 30%) and neonatal jaundice (37, or 4%). Of the hypoxaemic children, 37 (47%) had a final diagnosis of LRTI and 25 (32%), of neonatal sepsis. Among 78 hypoxaemic children, 22 (28%) died. Hypoxaemic children had higher mortality (age-adjusted RR: 4.3; 95% CI: 2.8–6.6). Admissions in the first week of life Of 1105 children (58% males) admit- ted during the first week of life, 206 (19%) were hypoxaemic on admission, and 336 (30%) died. Common final diagnoses were neonatal sepsis (600, or 54%); prematurity (216, or 20%); birth asphyxia (153, or 14%) and uncomplicated neonatal jaundice 98 (9%). Among those with hypoxaemia, neonatal sepsis (80, or 39%), birth asphyxia (62, or 30%), prematurity (49, or 24%) and neonatal jaundice (7, or 3%) were common. Among 206 children admitted with hypoxaemia, 118 (57%) died. This represented 35% of all deaths. Hypoxaemia was associated with inpatient death (age-adjusted RR: 2.4; 95% CI: 2.0–2.8). Clinical indicators of hypoxaemia Admissions aged ³ 60 days Clinical signs that appeared predictive on univariate analysis (LR ³ 2.0 or £ 0.5) were lower chest wall indrawing, nasal flaring, central cyanosis, irregular breathing, deep breathing, stridor, auscultatory crackles, dullness on per- cussion, respiratory rate ³ 60 breaths per min, weak pulse volume, delayed capillary refill (³ 3 s), heart rate < 80 beats per min, impaired conscious- ness with a Blantyre coma scale < 3, prostration, convulsion on admission, restlessness and hypothermia (Table A1 in Appendix A, available at: http://www. kemri-wellcome.org/images/appendixa. pdf ). On multivariate analysis within each group, central cyanosis, heart rate < 80 beats per min, irregular breathing, impaired consciousness with a Blantyre coma scale < 3, respiratory rate ³ 60 breaths per min, delayed capillary refill 266 Bull World Health Organ 2009;87:263–270 | doi:10.2471/BLT.07.049148 Research Emergency triage for hypoxaemia in Kenyan children Michael K Mwaniki et al. (³ 3 s) and weak pulse volume remained predictive of hypoxaemia (Table A2 in Appendix A). The overall sensitivity and specific- ity of these signs in the validation data set are shown in (Table 1). Although lower chest wall indrawing did not meet our criteria as a useful predictor when included with other signs in the respira- tory group, we re-tested it with the final list of predictive signs because it is easy to recognize clinically and WHO rec- ommends it as an indication for oxygen therapy when severe. Although includ- ing lower chest wall indrawing improved sensitivity, significant specificity was lost (Table 1). The area under the ROC curve of these signs in the validation set was 0.80 (95% CI: 0.77–0.84) overall, 0.77 (95% CI: 0.73–0.82) among chil- dren who fulfilled the clinical criteria for a pneumonia syndrome, and 0.81 (95% CI: 0.75–0.89) among children who did not fulfil them. Admissions aged 7–59 days The clinical signs that appeared predic- tive on univariate analysis were cya- nosis, irregular breathing, nasal flaring, crackles on auscultation, respiratory rate > 80 per min, weak pulse, delayed capillary refill (³ 3 s), heart rate < 100 beats per min, absent cry, unrespon- siveness to painful stimuli, convulsions Table 1. Performance of clinical predictors of hypoxaemia in children ³ 60 days of agea admitted to Kilifi District Hospital, Kenya Clinical signs No. with sign No. without sign True positives False positives True negatives False negatives Sensitiv- ity, % Specific- ity, % PPV, % NPV, % Cyanosis, heart rate < 80 beats/min or irregular breathing 110 3733 30 80 3583 148 17 98 27 96 Capillary refill ³ 3 seconds, weak pulse, or any of the signs listed above in this column 413 3430 62 351 3314 116 35 90 15 97 Respiratory rate > 60 breaths/min or any of the signs listed above in this column 643 3200 89 554 3111 89 50 85 14 97 Impaired consciousness (BCS < 3), or any of the signs listed above in this column 772 3071 113 659 3006 65 64 82 15 98 Lower chest wall indrawing, or any of the signs listed above in this column 1410 2433 151 1259 2406 27 89 67 11 99 BCS, Blantyre coma scale; NPV, negative predictive value; PPV, positive predictive value. a n = 3843; 178 (4.6%) of the children admitted were hypoxaemic. present on admission, restlessness, a bulging fontanelle and axillary tempera- ture < 36°C (Table A3 in Appendix A). Cyanosis, heart rate < 100 beats per min, respiratory rate > 80 breaths per min, irregular breathing, unresponsive- ness to painful stimuli, restlessness, in- ability to breastfeed and delayed capillary refill (³ 3 s) remained predictive after controlling for other signs (Table A4 in Appendix A). For the reasons given above, we also re-tested lower chest wall indrawing in the final list of signs. The sensitivity and specificity of the signs are shown in Table 2. The area under the ROC curve for the prospective validation data set was 0.77 (95% CI: 0.71–0.84). Admissions the first week of life In this group of children, predictive signs on univariate analysis were cyano- sis, irregular breathing, deep breathing, respiratory rate > 80 breaths per min, auscultatory crackles, indrawing, nasal flaring, heart rate < 100 beats per min, weak pulse, delayed capillary refill (³ 3 s), absent cry, unresponsiveness to painful stimuli, history of birth asphyxia and birth trauma (Table A5 in Appendix A). Signs that remained significantly associated on multivariate analysis were cyanosis, heart rate < 100 beats per min, irregular breathing, absent cry, unresponsiveness to painful stimuli, respiratory rate > 80 breaths per min, history of birth asphyxia, de- layed capillary refill (³ 3 s) and inability to breastfeed (Table A6 in Appendix A). The sensitivity and specificity of the signs are shown in (Table 3). For these signs, the area under the ROC in the validation set was 0.76 (95% CI: 0.72–0.81). Discussion Most studies of the prevalence and clini- cal signs of hypoxaemia have focused on children with LRTI. We therefore chose to examine unselected paediatric admissions. Hypoxaemia was present in 5%–19% of all children admitted to a Kenyan district hospital, depending on age, and this concurs with recent data from the Gambia.19 Although two-thirds of hypoxaemic children aged ³ 60 days presented with one of the clinical syndromes of pneumonia, only one-third had a final diagnosis of LRTI. Most children meeting the WHO criteria for very severe pneumonia were finally diagnosed with severe illnesses other than LRTI, most commonly severe malaria or shock. Children who have metabolic acidosis in severe ma- laria may present with respiratory dis- tress (Kussmaul’s respiration) and could thus overlap with the syndrome of very 267Bull World Health Organ 2009;87:263–270 | doi:10.2471/BLT.07.049148 Research Emergency triage for hypoxaemia in Kenyan childrenMichael K Mwaniki et al. Table 2. Performance of clinical predictors of hypoxaemia in children 7-59 days of agea admitted to the Kilifi District Hospital, Kenya Clinical signs No. with sign No. with- out sign True positives False positives True negatives False negatives Sensitiv- ity, % Specific- ity, % PPV, % NPV, % Cyanosis, heart rate < 100 beats/min, irregular breathing 27 362 6 21 331 31 16 94 22 91 Respiratory rate > 80 breaths/min, or any of the signs listed above in this column 39 350 8 31 321 29 22 92 21 92 Capillary refill ³ 3 seconds, or any of the signs listed above in this column 48 341 10 38 314 27 27 90 21 92 Inability to breastfeed, or any of the signs listed above in this column 94 295 22 72 280 15 60 80 26 95 Unresponsiveness to painful stimuli, restlessness, or any of the signs listed above in this column 104 285 23 81 271 14 62 77 10 95 Lower chest wall indrawing, or any of the signs listed above in this column 212 177 35 177 175 2 95 50 10 98 NPV, negative predictive value; PPV, positive predictive value. a n = 389; 37 (10%) of the children admitted were hypoxaemic. severe pneumonia.11,20,21 The situation may differ in geographical regions where malaria is not endemic. Clinical signs were relatively poor predictors of hypoxaemia. The most sensitive rules we developed still missed 5–15% of hypoxaemic children, de- pending on age. As in other studies, specificity posed a significant problem, as it was markedly reduced when we included lower chest wall indrawing (82–67% among children ³ 60 days of age and 77−50% among infants aged 1 week to 59 days) and the inability to breastfeed among infants in the first week of life (66−45%). Had we fol- lowed these rules, even after excluding lower chest wall indrawing at all ages and an inability to breastfeed in the first week of life, we would have given bottled oxygen to a total of 862 of 4695 (18%) children in the validation set who were not hypoxaemic by pulse oximetry. Although the false positive and false negative assessment results were fewer than reported recently from Papua New Guinea, they still represent a significant financial burden.22 At an estimated daily cost of US$ 6−14 per child on oxygen at 1 litre per min (depending on the size of cylinder available), in our setting this would have translated into US$ 5172 to US$ 12 068 in 1 year had each child not requiring oxygen (862) received it for 1 day.2 A hand-held pulse oxymeter costs less than US$ 1000. Where supplies of oxygen are lim- ited and pulse oximetry is unavailable, as in most health facilities that treat severely ill children in resource-limited settings, prioritization depends on clinical signs. The signs we found to be most strongly predictive of hypoxaemia among admissions aged ³ 60 days cor- respond with those given in the com- bined chapters of “triage and emergency conditions” and the “cough and difficult breathing” in the current WHO guide- lines.11 The signs of shock (delayed capillary refill and a weak pulse volume) included in the triage guidelines have not been evaluated in previous studies of hypoxaemia in this setting, and in- cluding them in the WHO emergency care guidelines appears to be justified as part of the assessment of the airway, breathing and circulation. Importantly, hypoxaemia detected by transcutane- ous measurement may be due in part to poor tissue perfusion (hence poor peripheral oxygenation), and oxygen may therefore be needed only in the initial stabilization phase. Although a slow heart rate and irregular breath- ing are not included in the currently recommended triage assessment, they were among the strongest predictors of hypoxaemia in our study. These signs, together with the signs of shock, led to identification of 50% of the cases of hypoxaemia and had reasonable speci- ficity (85%). Importantly, although cyanosis alone was a very strong positive predictor (LR: 24), few of the children admitted had this sign, and the absence of cyanosis was not predictive of nor- mal oxygenation (LR: 0.94). Lower chest wall indrawing by itself was a weak predictor of hypoxaemia, and signs such as pallor, dullness on chest percussion, wheeze or crackles were not predictive. We did not include labora- tory results in the final models because they are seldom available when an initial decision regarding oxygen therapy has to be made. We performed separate analyses for different age groups on the hypothesis that predictive signs may differ in each. However, we found the signs to be 268 Bull World Health Organ 2009;87:263–270 | doi:10.2471/BLT.07.049148 Research Emergency triage for hypoxaemia in Kenyan children Michael K Mwaniki et al. Table 3. Performance of clinical predictors of hypoxaemia in children less than 1 week of agea admitted to Kilifi District Hospital, Kenya Clinical signs No. with sign No. with- out sign True positives False positives True negatives False negatives Sensitiv- ity, % Specific- ity, % PPV, % NPV, % Cyanosis, heart rate < 100 beats/min, irregular breathing 107 356 47 60 298 58 45 83 44 84 Respiratory rate > 80 breaths/min, or any of the signs listed above in this column 122 341 49 73 285 56 47 80 40 84 Unresponsiveness to painful stimuli, absent cry, or any of the signs listed above in this column 143 320 58 85 273 47 55 76 41 88 Capillary refill ³ 3 seconds, or any of the signs listed above in this column 159 304 64 95 263 41 63 74 40 90 History of birth asphyxia, or any of the signs listed above in this column 194 269 81 113 245 24 79 66 42 91 Inability to breastfeed, or any of the signs listed above in this column 286 177 97 189 169 8 94 45 34 96 NPV, negative predictive value; PPV, positive predictive value. a n = 463; 105 (23%) of the children admitted were hypoxaemic. remarkably similar. Few studies have looked at hypoxaemia in neonates and young infants in this setting. One study of 132 neonates in Papua New Guinea showed that a model of cyanosis, re- spiratory rate > 70 breaths per min, or respiratory rate < 30 breaths per min and reduced activity could predict hypoxaemia with a sensitivity of 84% and a specificity of 55%.23 A recent study from the Gambia showed that the prevalence of hypoxaemia in neonates was about 16.5%.19 However, in that study 40% of all neonatal admissions were missed. Importantly, no neonates were recruited in the first week of life. Our study has several weaknesses. We did not collect data on head nod- ding and grunting, which have yielded variable findings in previous studies.4,9 Pulse oximetry was performed routinely during admission, and the admitting clinicians were not blinded to the SaO2 results during their initial clinical as- sessment. However, the low sensitivity of signs such as cyanosis, commonly re- garded as a cardinal sign of hypoxaemia, and the fact that the predictive value of the clinical signs was similar to that reported in other studies, suggest that clinicians were not unduly influenced when recording their findings.1,8 A gen- eralized problem is that among children admitted with overt shock and signs of poor circulation, peripheral pulse oxim- etry results may not always accurately reflect core hypoxaemia.24 We defined hypoxaemia as an SaO2 < 90% by pulse oximetry.11 However, children aged ³ 60 days whose SaO2 was 90−94% had a higher case fatal- ity proportion (102/1339, or 7.6%) than those whose SaO2 was ³ 95% (503/11 203, or 4.5%) (P < 0.001). Some children with an SaO2 of 90−95% may benefit from oxygen supplemen- tation; further studies are needed to elucidate if oxygen affects the outcome at this level. Our findings strongly support current WHO recommendations sur- rounding triage for the detection of hypoxaemia. This is important because almost all prior studies have only included children thought to have pneumonia, and none has evaluated the triage signs of shock. Based on our findings, we advise against excessive emphasis on LRTI, which may poten- tially result in the underdiagnosis of other conditions associated with respi- ratory distress and hypoxaemia. Rather, we recommend a structured approach to assessment and triage that will target children likely to have hypoxaemia ir- respective of the working diagnosis. Finally, pulse oximetry is essential for detecting hypoxaemia and is likely to save costs. ■ Acknowledgements We thank the Kenya Medical Research institute (KEMRI) and The Wellcome Trust (Grants codes 061584, 076278, 081186) for their support. We also thank the Medical Officer of Health, the Medical Superintendent and the paediatric staff of Kilifi District Hospi- tal. This article is submitted for publica- tion with the permission of the Director of the KEMRI. Competing interests: None declared. 269Bull World Health Organ 2009;87:263–270 | doi:10.2471/BLT.07.049148 Research Emergency triage for hypoxaemia in Kenyan childrenMichael K Mwaniki et al. Résumé Evaluation dans le cadre du triage d’urgence des cas d’hypoxémie parmi les nouveau-nés et les jeunes enfants dans un hôpital kenyan : étude d’observation Objectif Décrire la prévalence de l’hypoxémie chez les enfants admis dans un hôpital kenyan en vue d’identifier les signes cliniques de l’hypoxémie utilisables pour l’évaluation dans le cadre du triage d’urgence et tester l’hypothèse selon laquelle ces signes permettraient une identification correcte des enfants atteints d’hypoxémie, indépendamment du diagnostic qui doit leur être affecté. Méthodes De 2002 à 2005, nous avons recueilli prospectivement des données cliniques et des mesures par oxymétrie pulsée pour l’ensemble des admissions pédiatriques à l’hôpital de district de Kilifi au Kenya, indépendamment du diagnostic concernant ces enfants, et évalué la prévalence de l’hypoxémie en relation avec la présence d’un syndrome clinique de type pneumonie selon l’OMS lors de l’admission et du diagnostic final de sortie. Nous avons utilisé les données collectées sur les trois premières années pour déterminer les signes prédictifs de l’hypoxémie et les données de la quatrième année pour valider ces signes. Résultats Nous avons relevé une hypoxémie chez 977 des 15289 enfants hospitalisés (soit 6,4 %, chiffre variant entre 5 à 19 % selon la tranche d’âge) et une association forte entre hypoxémie et mortalité des patients hospitalisés (rapport de risques ajusté selon l’âge : 4,5 ; intervalle de confiance à 95 %, IC : 3,8-5,3). Si la plupart des enfants hypoxémiques de 60 jours et plus remplissaient, lors de leur admission, les critères OMS de définition du syndrome de type pneumonie, seuls 215 des 693 enfants hypoxémiques de 60 jours et plus (31 %) ont finalement été diagnostiqués comme atteints d’une infection des voies respiratoires inférieures (IVRI). Parmi les signes les plus prédictifs de l’hypoxémie figuraient l’état de choc, une fréquence cardiaque inférieure à 80 battements par minute, une respiration irrégulière, une fréquence respiratoire supérieure à 60 respirations par minute et un état de conscience altérée. Néanmoins, 5 à 15 % des enfants hypoxémiques lors de leur admission n’ont pas été repérés et 18 % des enfants ont été identifiés à tort comme hypoxémiques. Conclusion Le recours au syndrome de type pneumonie permet d’identifier la plupart des enfants hypoxémiques, y compris ceux atteints d’une IVRI. L’état de choc, la bradycardie et l’irrégularité respiratoire sont des signes prédictifs importants et le paludisme grave, avec détresse respiratoire, est une cause courante d’hypoxémie. Globalement néanmoins, les signes cliniques n’ont pas une grande valeur prédictive pour l’hypoxémie et il est probable que l’utilisation de l’oxymétrie pulsée par les établissements de soins qui manquent de moyens pour identifier les patients devant bénéficier d’un traitement par l’oxygène permettra de réaliser des économies. Resumen Triaje de emergencia de la hipoxemia en neonatos y niños de corta edad en un hospital de Kenya: estudio observacional Objetivo Describir la prevalencia de hipoxemia en niños ingresados en un hospital de Kenya a fin de identificar los signos clínicos de la misma para un triaje de emergencia, y contrastar la hipótesis de que esos signos permiten detectar correctamente la hipoxemia en los niños, independientemente del diagnóstico. Métodos Entre 2002 y 2005 se reunieron prospectivamente datos clínicos y de oximetría de pulso para todos los ingresos pediátricos en el Hospital de Distrito de Kilifi, Kenya, con independencia del diagnóstico, determinándose la prevalencia de hipoxemia en relación con el síndrome clínico de «neumonía» definido por la OMS en el momento del ingreso y con el diagnóstico final en el momento del alta. Los datos recogidos durante los tres primeros años se usaron para determinar los signos predictivos de hipoxemia, y los datos reunidos a partir del cuarto año fueron utilizados para validar esos signos. Resultados Se detectó hipoxemia en 977 de 15 289 (6,4%) niños ingresados (5%-19% según el grupo de edad), muy estrechamente asociada a mortalidad hospitalaria (razón de riesgos ajustada por edad: 4,5; intervalo de confianza [IC] del 95%: 3,8 - 5,3). Aunque la mayoría de los niños hipoxémicos con ³ 60 días de edad cumplían los criterios de la OMS para que pudiera diagnosticarse un síndrome de «neumonía» en el momento del ingreso, sólo 215 de los 693 (31%) niños hipoxémicos de esa edad recibieron un diagnóstico final de infección de las vías respiratorias inferiores (IVRI). Los signos más predictivos de hipoxemia fueron el choque, una frecuencia cardiaca < 80 latidos por minuto, una respiración irregular, una frecuencia respiratoria > 60 respiraciones por minuto y un deterioro de la conciencia. Sin embargo, no se detectó la hipoxemia en un 5%-15% de los niños que la sufrían en el momento del ingreso, y un 18% de los niños fueron considerados hipoxémicos incorrectamente. Conclusión Los síndromes de neumonía permiten identificar a la mayoría de los niños hipoxémicos, incluidos los que no presentan IVRI. Un cuadro de choque, la bradicardia y una respiración irregular son signos predictivos importantes, y la malaria grave con distrés respiratorio es una causa común de hipoxemia. Sin embargo, en general los signos clínicos son poco fiables como factores predictivos de la hipoxemia, y es probable que, en los servicios de salud con recursos escasos, el uso de la oximetría de pulso como criterio para aplicar oxigenoterapia permita ahorrar costos. صخلم ةبقارم ةسارد :ةينيكلا فياشلما دحأ في مدلا جسكأت صقنب ينباصلما لافطلأا راغصو ةدلاولا يثيدح نم ئراوطلا تلااح زرف ميـيقت دحأ في نولبقي نيذلا لافطلأا ىدل مدلا جسكأت صقن فصو :فدهلا ميـيقتل ةجسكلأا صقنل ةيريسرلا تاملاعلا لىع فرعتلل ةينيكلا تايفشتسلما تاملاعلا هذه لثم نأ لوقت يتلا ةيضرفلا رابتخلاو ئراوطلا تلااح زرف رظنلا ضغب ،لافطلأا ىدل مدلا جسكأت صقن لىع حيحصلا فرعتلا لىإ دوقت .صيخشتلا نع ةيلابقتسا ةقيرطب 2005 ماع لىإ 2002 ماع نم ةترفلا في انعمج :ةقيرطلا اولبق نيذلا لافطلأا عيمجل تاعفد لىع جسكأتلا سايقو ةيريسرلا تايطعلما انمَّيقو ،صيخشتلا نع رظنلا ضغب ،اينيك في لييفيك ةعطاقم ىفشتسم في 270 Bull World Health Organ 2009;87:263–270 | doi:10.2471/BLT.07.049148 Research Emergency triage for hypoxaemia in Kenyan children Michael K Mwaniki et al. 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PMID:3808804 ةحصلا ةمظنلم ةيريسرلا تامزلاتلماب قّلعتي مايف جسكأتلا صقن راشتنا لدعم صيخشتلابو ىفشتسلما في لوبقلا تقو ”يوئرلا باهتللاا“ لوح ةيلماعلا هانعمج ام انمدختساو .ىفشتسلما نم جيرختلا دنع عضو يذلا ئياهنلا صقنب ةئبنلما تاملاعلا ديدحتل لىولأا ثلاثلا تاونسلا للاخ تايطعم نم هذه ةيقودصم قيثوتل ةعبارلا ةنسلا نم ةدمتسلما تايطعلماو ،ةجسكلأا .تاملاعلا ةلاح 15 289 لصأ نم ةلاح 977 ىدل جسكأتلا صقن اندجو :تادوجولما تطبترا دقو ،)ةيرمعلا ةعومجملل ًاقفو %19-5( ينلوبقلما عيمجل )%6.4( غلب( ىفشتسلما لخاد ةلوبقلما تلااحلا ينب تايفولا لدعبم ًاقيثو ًاطابترا لدعم حوارت ذإ %95 ةقث لصافب ،4.5 رمعلا قفو ححصلما راطتخلاا بسنم جسكأتلا صقنب ينباصلما لافطلأا مظعم نأ مغرو .)5.3و 3.8 ينب ةيحجرلأا ةيلماعلا ةحصلا ةمظنم يرـياعم اوقّقح دق ًاموي 60 نع مهرماعأ ديزت نيذلا 693 ينب نم طقف 215 نإف ،ىفشتسلما في مهلوبق دنع ”يوئرلا باهتللال“ ًاموي 60 نع مهرماعأ ديزت نيذلاو جسكأتلا صقنب ينباصلما لافطلأا نم مهأ امأ .ةيلفسلا ةيسفنتلا لبسلا باهتلا ئياهنلا مهصيخشت ناك )%31( 80 نم لقلأ بلقلا ءطبو ،ةمدصلا يهف جسكأتلا صقنل ةتبثلما تاملاعلا ًاسفن 60 نم ثركلأ سفنتلا ةعسرو ،سفنتلا مُظُن بارطضاو ،ةقيقدلاب ةبضر لافطلأا نم %15-5 صيخشت اندقف اننإف كلذ مغرو .يعولا رثأتو ،ةقيقدلاب وفصو دق لافطلأا نم %18 نأ ماك ،مهلوبق دنع جسكأتلا صقنب ينباصلما .جسكأتلا صقنب نوباصم مهنأ لىع أطخ ينباصلما لافطلأا مظعم ّينبت نأ يوئرلا باهتللاا ضارعلأ نكيم :جاتنتسلاا امأ .ةيلفسلا ةيسفنتلا لبسلا باهتلاب نوباصلما مهنمو ،جسكأتلا صقنب ،ةماه ةئبنم تاملاع يهف سفنتلا مظن بارطضاو بلقلا ءطبو ةمدصلا .جسكأتلا صقنل عئاش ببس ةيسفنت ةسرعب ةقفاترلما ةميخولا ايرلالما نأ ماك ،جسكأتلا صقن لىع ةئيس تائبنم ةيريسرلا تاملاعلا نأ ماع لكشب ةجيتنلاو دراولماب ةيرقفلا ةيحصلا قفارلما في تاعفد لىع جسكأتلا سايق مادختسا نأو .فيلاكتلا رفوي دق ينجسكلأاب ةجلاعلما هيجوتل