Pulse oximetry and factors associated with hemoglobin oxygen desaturation in children with sickle cell disease

Abstract

The observation of low transcutaneous arterial oxygen saturation (SaO2) in otherwise well sickle cell patients has lead to questions about the interpretation of pulse oximetry values in these patients. We undertook a prospective study of children with sickle cell disease to (1) determine the prevalence of, and factors associated with, low transcutaneous SaO2 in clinically well patients, (2) develop an algorithm for the use of pulse oximetry in acutely ill patients, and (3) assess the accuracy of pulse oximetry in these patients. Eighty-six clinically well children with hemoglobin (Hb) SS had a lower mean transcutaneous SaO2 than 22 Hb SC patients and 10 control subjects (95.6% v 99.1% v 99.0%, respectively; p < .001). In Hb SS patients, a history of acute chest syndrome and age greater than 5 years were associated with lower transcutaneous SaO2 (mean 93.8% for those with a history of acute chest syndrome v 97.8% for those without a history of acute chest syndrome, and 94.0% for patients = 5 years old v 97.2% for those < or = 5 years old; P < .001). These associations were not seen in Hb SC patients. During acute illness, Hb SS patients with acute chest syndrome had transcutaneous SaO2 values that were less than 96% and at least 3 points lower than measurements made when they were well. A nomogram was designed to aid in the interpretation of transcutaneous SaO2 in acutely ill Hb SS patients when a comparison value is not available. The accuracy of pulse oximetry was shown by the correlation between SaO2 measured by pulse oximetry and calculated by using the patient's oxygen dissociation curve and PaO2 (r = .97). This study provides evidence that Hb oxygen desaturation is not a universal finding among children with sickle cell disease and identifies factors associated with Hb oxygen desaturation. We conclude that pulse oximetry may be useful to assess whether progressive pulmonary dysfunction begins at an early age in Hb SS patients, and to assess acutely ill patients for the presence of hypoxemia associated with acute chest syndrome.

Prospective evaluation of haemoglobin oxygen saturation at rest and after exercise in paediatric sickle cell disease patients

“…This study is limited by the fact that arterial blood gases were not performed to confirm pO 2 and oxygen saturation, and some evidence suggests that pulse oximetry is not reliable in sickle cell disease (Blaisdell et al , 2000). However, a number of other studies have indicated that pulse oximetry is reliable for diagnosing hypoxia during steady state conditions and with acute complications in sickle cell disease patients (Rackoff et al , 1993; Kress et al , 1999; Ortiz et al , 1999). Another limitation of our study is that it is cross‐sectional rather than longitudinal.…”

“…Nocturnal oxygen desaturation is also a risk factor for stroke, silent infarct or seizure (Kirkham et al , 2001). On the other hand, reported associations of lower haemoglobin oxygen saturation with increased episodes of pain (Hargrave et al , 2003) and acute chest syndrome (Rackoff et al , 1993), manifestations of the vaso‐occlusive subphenotype, have not been confirmed in other studies (Quinn & Ahmad, 2005; Uong et al , 2006).…”

“…A lowering of the haemoglobin oxygen saturation as determined by pulse oximetry is common in patients with sickle cell disease at steady state despite the lack of overt evidence of pulmonary dysfunction or intrinsic lung disease (Rackoff et al , 1993; Homi et al , 1997; Setty et al , 2003; Quinn & Ahmad, 2005). Decreased affinity of haemoglobin S for oxygen (Seakins et al , 1973; Ueda et al , 1979) and increased erythrocyte 2,3‐bisphosphoglycerate (Milner, 1974) may partially, but probably not fully, explain decreased oxygen saturation in sickle cell disease given the wide range of saturations in patients.…”

“…Decreased affinity of haemoglobin S for oxygen (Seakins et al , 1973; Ueda et al , 1979) and increased erythrocyte 2,3‐bisphosphoglycerate (Milner, 1974) may partially, but probably not fully, explain decreased oxygen saturation in sickle cell disease given the wide range of saturations in patients. Several groups have reported the association of low haemoglobin oxygen saturation in sickle cell disease with elevated serum lactate dehydrogenase, severity of anaemia and/or reticulocytosis, suggesting a possible aetiological relationship of haemolysis with hypoxemia (Rackoff et al , 1993; Homi et al , 1997; Setty et al , 2003; Quinn & Ahmad, 2005; Kato et al , 2006). It has been proposed that this association might involve haemolysis‐associated ventilation‐perfusion mismatch (Kato et al , 2007a).…”

Tricuspid regurgitation velocity and other biomarkers of mortality in children, adolescents and young adults with sickle cell disease in the United States: The PUSH study

“…N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) ≥160 ng/L has been used to define an elevated value in numerous previous studies 18‐21 . Hemoglobin oxygen saturation ≤ 95% has been suggested to identify SCD children at risk for hypoxia 22 . Glomerular filtration rate (GFR) <90 mL/minutes/1.73 m 2 is the cutoff that defines Stage I decline in GFR by Kidney Disease: Improving Global Outcomes (KDIGO) guidelines 23 .…”