Lowest Arterial Oxygen Saturation Research Articles

Detection of extrinsic bronchial compression during foreign body removal by pulse oximetry

A case of stridor is described which was due to the presence of a foreign body in the larynx of an infant. Following partial removal, compression of the right main bronchus was detected because of continuing low arterial oxygen saturation. The use of pulse oximetry allowed this complication to be identified, and the advantages of this method of monitoring are discussed.

The effect of prolonged intrauterine hyperinsulinemia on iron utilization in fetal sheep.

Newborn infants of poorly controlled insulin-dependent diabetic mothers demonstrate a redistribution of iron from serum and tissue stores into red blood cells. These changes may be due to increases in iron utilization during augmented Hb synthesis, which compensates for chronic intrauterine hypoxemia induced by prolonged fetal hyperinsulinemia. We tested this hypothesis by measuring plasma iron, total iron-binding capacity, percent iron-binding capacity saturation (total iron-binding capacity saturation), Hb concentration, total red cell Hb, and total red cell iron in the arterial blood of 11 chronically instrumented fetal sheep after 7-12 d of infusion with 15 U/day of insulin (n = 5) or placebo (n = 6). The insulin-infused fetal sheep had higher mean +/- SD plasma insulin concentrations (448 +/- 507 versus 11 +/- 8 mU/L; p less than 0.001) and lower arterial oxygen saturations (38 +/- 7 versus 54 +/- 9%; p less than 0.02). The insulin-infused group had a lower mean plasma iron concentration (20.8 +/- 10.9 versus 42.1 +/- 14.7 microM/L; p less than 0.02) and total iron-binding capacity saturation (36 +/- 20 versus 64 +/- 22%; p less than 0.02) and a higher total red cell Hb (45.4 +/- 8.7 versus 32.6 +/- 8.8 g; p less than 0.02) and total red cell iron content (154 +/- 29 versus 111 +/- 29 mg; p less than 0.02) when compared with the placebo group. Seven to 12 d of intrauterine hyperinsulinemia decreases serum iron and increases total red cell iron, most likely by stimulating increased Hb synthesis in response to low arterial oxygen saturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of submental electrical stimulation during sleep on upper airway patency in patients with obstructive sleep apnea.

We examined the effects of percutaneous electrical stimulation of the genioglossus in six patients with obstructive sleep apnea syndrome (OSAS) during sleep and investigated the possible applicability of this procedure as a treatment of OSAS. Six patients with OSAS were polysomnographically studied in the supine position during all-night sessions with and without electrical stimulation of the genioglossus. Using an apnea demand-type stimulator that we developed, electrical pulses of 0.5 ms (repetition rate, 50 Hz) and 15 to 40 V were delivered through bipolar electrodes (10 mm in diameter) attached to the skin of the submental region when apnea lasted more than 5 s, and was stopped immediately after breathing resumed or after 10 s at the longest. With submental stimulation, the apnea index, apnea time/total sleep time, longest apnea duration, and the number of times per hour that oxygen saturation dropped below 85% decreased significantly compared with those on control nights. The lowest arterial oxygen saturation and the duration of sleep stages III and IV increased significantly. The stimulation employed did not cause arousal, and it did not affect blood pressure or heart rate significantly. These findings show that submental stimulation decreases the incidence of apnea episodes and promotes deeper sleep without accompanying serious side effects, suggesting that the apnea demand-type stimulator may be a noninvasive and effective treatment for OSAS.

Breathing, Sleep, and Diabetic Autonomic Neuropathy

Sudden, unexplained deaths are relatively common in diabetic autonomic neuropathy. As disturbed autonomic function has been associated with sleep apnea, and sleep apnea with sudden death, we recorded breathing patterns, arterial oxygen saturation, and EEG during sleep in 8 male diabetic subjects with severe autonomic neuropathy and 8 age-matched, male diabetic subjects without autonomic neuropathy. None of the patients with autonomic neuropathy had more than 11 apneic episodes per night, and there were no significant differences between the two groups in the number of sleep apneas, the duration of individual apneic episodes, the total duration of irregular breathing during sleep, or the duration and quality of sleep. The arterial oxygen saturation when awake and the lowest arterial oxygen saturation during sleep were also similar in both groups. Thus, diabetic patients with severe autonomic neuropathy have normal breathing patterns and oxygenation during sleep, and it is unlikely that sleep apnea causes these unexpected deaths.

Factors influencing survival after balloon atrial septostomy for complete transposition of great arteries.

Despite balloon atrial septostomy within the first days of life, some patients with complete transposition of the great arteries die before reaching elective definitive surgery in the second six months of life. To discover why, we analysed the fate of 144 patients who had balloon atrial septostomy after 1966, using a modified logrank survival test with multivariate capability. Patients were withdrawn "alive" on reaching definitive surgery. The following largely independent factors were associated with a statistically significant excess mortality: pulmonary hypertension, the presence and size of a ventricular septal defect of persistent ductus arteriosus, relative anaemia, absence of left ventricular outflow tract obstruction, low arterial oxygen saturation, aortic stenosis and coarctation, and balloon atrial septostomy between 1 week and 1 month of life. Those of the above factors which can be determined at balloon atrial septostomy or at routine cardiac catheterisation at 3 months of age were then introduced into discriminant function analysis on survival to 6 months. Hence the probability of any individual patient dying in the first six months was calculated, allowing for these factors. This prediction was correct in 76 per cent of the patients studied. By offering earlier definitive correction to patients thus identified as being at high risk of premature death, it should prove possible to reduce overall mortality in transposition of the great arteries.

Clinical manifestations of dynamic left ventricular outflow tract stenosis in infants with d-transposition of the great arteries with intact ventricular septum

Four infants with d-transposition of the great arteries and intact ventricular septum who manifested early clinical symptoms and deterioration due to dynamic left ventricular outflow stenosis are presented. All four had an anatomically adequate atrial septal defect, made at the initial balloon atrial septostomy, that was later confirmed intraoperatively. Two infants continued to have a low arterial oxygen saturation level because of inadequate interatrial mixing, and one of these had severe persistent cyanosis and was treated with the Mustard operation at age 4 days. The other two infants subsequently presented with hypercyanotic spells at age 3 months. All four infants had features of dynamic left ventricular outflow stenosis on hemodynamic, angiocardiographic and echocardlographic studies. The left ventricular outflow pressure gradient was shown to increase after administration of isoproterenol in one infant, and relief of a cyanotic spell with reduction of left ventricular systolic pressure was achieved in another after intravenous administration of propranolol. The Mustard operation relieved symptoms in all infants. The effect of left ventricular outflow tract stenosis on the mechanisms responsible for interatrial mixing in d-transposition of the great arteries with intact ventricular septum is discussed.

Hypoxemia and critical flicker frequency in congenital heart disease.

The relationship between the arterial oxygen saturation level and performance on a centrally mediated task was determined in patients with congenital heart disease. The critical flicker frequency (CFF) of 212 acyanotic and 66 cyanotic patients with congenital heart disease, with arterial oxygen saturation levels below 90%, was determined by a standardized technique. The CFFs of the cyanotic patients as a group were significantly lower than those of the acyanotic patients. Within the cyanotic group, the patients with the lower arterial oxygen saturation level had the lower CFFs. These data support the hypothesis that the hypoxemia associated with cyanotic congenital heart disease does impair central nervous system functioning.

Postoperative assessment of patients with ventricular septal defect and pulmonary hypertension. Response to intense upright exercise.

Circulatory function of patients with operatively closed ventricular septal defect and preoperative pulmonary arterial hypertension was evaluated in 11 asymptomatic subjects at rest and during intense treadmill exercise three to 15 years after operation. The pulmonary-to-systemic resistance ratio was normal or mildly to moderately elevated preoperatively. Postoperative mean pulmonary arterial pressure at the time of study was normal or mildly elevated at rest in 10 patients and moderately elevated in one (40 mm Hg). During intense upright exercise sufficient to lower pulmonary arterial oxygen saturation to 30%, cardiac output was below the normal range in five patients. Each of these patients had been operated upon after 10 years of age. The magnitude of the postoperative abnormality in cardiac output response to exercise was directly related to age at operation. Two of the five patients with impaired cardiac output response and two other patients manifested an abnormally elevated mean pulmonary arterial pressure during intense exercise. There was a positive correlation between pulmonary arterial pressure during intense exercise and age at operation. These results indicate that late postoperative cardiovascular function may be abnormal in patients with ventricular septal defect and preoperative pulmonary arterial hypertension, and that these abnormalities appear to be related to age at operation. Since all patients were asymptomatic, the long-term clinical significance of these hemodynamic abnormalities remains to be determined.

The ventilatory response to hypoxia during exercise in cyanotic congenital heart disease.

1. In contrast to the diminished ventilatory response to hypoxia which has been found at rest in cyanotic congenital heart disease, hyperventilation was noted on exercise in children who were cyanosed. 2. Sixteen children had low arterial oxygen saturations on exercise and thirteen of these hyperventilated by an amount similar to that reported in normal adults breathing hypoxic gas mixtures. 3. The three children who had little ventilatory response in relation to the increase of hypoxia during exercise all had a triad of long-standing cyanosis starting early in life, high haemoglobin concentration and low arterial oxygen saturation at rest in air.

Hemodynamic abnormalities in response to mild and intense upright exercise following operative correction of an atrial septal defect or tetralogy of Fallot.

Patients are often asymptomatic after operative correction of an atrial septal defect (ASD) or tetralogy of Fallot (TF). However, the maximal functional capacity of their hearts relative to that of normal subjects has not been defined. Twelve asymptomatic patients who had ASDs closed and 10 asymptomatic patients who had total correction of tetralogy of Fallot were evaluated by catheterization studies at rest and during mild and intense treadmill exercise. Except for small right ventricular outflow gradients in the tetralogy of Fallot group (2-21 mm Hg), data recorded at rest were normal or nearly so in each subject. However, at a level of upright exercise sufficiently intense to lower pulmonary arterial oxygen saturation to 30%, cardiac output was below that attained by normal subjects (mean, 8.9 ± 0.3 liters/min/m 2 ) in seven of 12 ASD patients (mean, 6.6 ± 0.6 liters/min/m 2 ) and in eight of 10 tetralogy of Fallot patients (mean, 6.1 ± 0.3 liters/min/m 2 ). Right ventricular (RV) outflow gradients, measured during upright exercise in six TF patients, increased in each; RV systolic pressures reached levels of 75-106 mm Hg in four of the six patients studied. No outflow gradients were observed in the ASD group. Thus, patients with operative closure of an ASD and normal hemodynamic findings at rest may have impairment of their cardiac output response to intense upright exercise in the absence of residual shunts, arrhythmias, or pulmonary arterial hypertension. Although the cardiac output response in patients with corrected tetralogy of Fallot is consistently reduced, it is remarkably good considering the complicated nature of their defect and operative repair; however, the RV outflow gradient and RV systolic pressure may increase markedly with exercise. The longterm significance of these findings remains to be determined.

Chronic obstructive bronchopulmonary disease: II. Oxygen transport in two clinical types

Two contrasting types of patients with chronic airway obstruction were distinguished by purely clinical criteria: the emphysematous type (herein referred to as PP patients) and the bronchial type (BB patients). In the autopsy cases there was somewhat more extensive emphysematous destruction of the lungs and much less evidence of active bronchial mucous gland hyperplasia in the former type than in the latter. These two types of patients were studied physiologically and were found to have equivalent degrees of ventilatory impairment. However, PP patients had larger lungs, more uniform distribution of inert gas (helium) and hyperventilated both at rest and during exercise. BB patients had higher carbon dioxide tensions and much lower arterial oxygen saturations than did PP patients. The severe hypoxemia in BB patients was not caused by alveolar hypoventilation per se nor could it be satisfactorily explained by calculations of gas and blood flow distribution in the lungs. The most consistent measured difference relevant to pulmonary oxygen transport in the two types was in pulmonary blood flow: PP patients had subnormal and BB patients normal cardiac outputs both at rest and during exercise. The higher ratio of total ventilation to total blood flow in PP patients probably accounted for the nearly normal arterial oxygenation. The hypoxemia in BB patients is considered to be a form of diffusion impairment resulting from too rapid flow of red blood cells through hypoventilated alveoli. The most consistent measured difference relevant to tissue oxygenation in the two types was in the systemic oxygen transport (product of total blood flow and arterial blood oxygen content). Because of their low cardiac outputs, PP patients, although their arterial blood had a higher oxygen pressure, delivered less oxygen to their tissues than BB patients, who maintained a normal cardiac output despite a greater degree of pulmonary hypertension. These findings may account for the cachexia of the former and the cor pulmonale of the latter patients.

Cyanosis with hepatic cirrhosis. A case with pulmonary arteriovenous shunting.

A case is reported of cirrhosis of the liver associated with cyanosis and finger clubbing in a man of 31 years. The chest radiograph showed diffuse nodular shadows in both lower zones. Pulmonary function tests gave an arterial oxygen saturation of 91% at rest, falling to 68% on exercise; the single breath diffusing capacity for carbon monoxide was reduced to 55% of the predicted value and there was an estimated right-to-left shunt of 23%. Post-mortem injection of the lungs with Micropaque-gelatin suspension showed numerous pleural spider naevi, denser over the lower lobes, arteriovenous communications in the infrahilar regions, including leashes of dilated vessels in pleural adhesions on the diaphragm and diffuse arterial vasodilatation in the lungs; although the injection mass could be traced into the pulmonary veins in only a few regions of the lung, the dilated arterioles and spiders were possible additional channels through which blood might be shunted from the alveolar surfaces. The very low arterial oxygen saturation on exercise was probably caused by a shunt greater than the 23% estimated at rest, but the low diffusing capacity may have been partly responsible. The cause of the low diffusing capacity remains uncertain.

Atrioventricular block as a complication of cardiac catheterization in infants and children

Atrioventricular block was accidentally produced in 51 patients during the courseof 1,556 consecutive cardiac catheterizations over a ten-year period in a children's hospital. A majority of these incidents occurred in infants under 1 year of age. Although the duration of heart block was usually short and not attended by serious consequences, in 6 patients heart block persisted for periods up to 6 days, and 2 small infants died with the arrhythmia unrelieved. Factors important in the production of heart block during cardiac catheterization include the presence of a low arterial oxygen saturation, and a cardiac malformation which for diagnosis requires increased manipulation of the catheter.

Effects of arterial carbon dioxide tension and oxygen saturation on cerebral blood flow autoregulation in dogs.

ABSTRACTEffects of arterial carbon dioxide tension and oxygen saturation on cerebral blood flow autoregulation in dogs. Acta physiol. scand. 1965. 66. Suppl. 258. 27–53. ‐ Pressure‐flow relation‐ ships of the cerebral circulation under influence of variations in arterial carbon dioxide tension and oxygen saturation were studied in pentobarbital anaesthetized dogs. Cerebral blood flow was measured by recording of the γ‐ emission of radioactive krypton (Kr85), which was injected into the vertebral artery. The recorded desaturation curve was resolved into two exponential phases and the fast phase was considered as representative of blood flow in the grey matter of the brain. It was demonstrated that autoregulation of flow occurred within wide pressure limits under normo‐ and hypocapnia. Auto‐regulation was less pronounced under hypercapnia and was abolished at low arterial oxygen saturation. Possible mechanisms of autoregulation of cerebral blood flow are discussed. Evidences are presented which speak against the theory that changes in the carbon dioxide tension are the main cause of this autoregulation. The results from previous studies concerning the principal effects of arterial carbon dioxide tension and oxygen saturation on cerebral blood flow were confirmed.

CAUSE OF LOW ARTERIAL OXYGEN SATURATION IN PULMONARY FIBROSIS.

CAUSE OF LOW ARTERIAL OXYGEN SATURATION IN PULMONARY FIBROSIS.

DIGITAL CLUBBING IN CHRONIC OBSTRUCTIVE LUNG DISEASE.

SummaryFinger clubbing was detected in 24% of 50 patients with chronic obstructive lung disease. The patients with clubbing had a lower mean arterial oxygen saturation than those without clubbing, and no patient with clubbing had a normal arterial oxygen saturation. All patients with clubbing had abnormally large veno‐arterial shunts, and this may be of some ætiological significance.

Circulatory changes in chronic liver disease

The circulatory findings in twenty-four patients with portal cirrhosis were compared with results in six patients with biliary cirrhosis, six patients with extrahepatic portal vein obstruction and fourteen normal subjects. Half the patients with portal cirrhosis had a cardiac index above the upper limit of normal. Clinically, these patients had evidence of increased peripheral blood flow and ejection systolic murmurs. Roentgenographic or electrocardiographic changes were uncommon. Patients with biliary cirrhosis and portal vein obstruction had normal cardiac indices. An increased total blood volume, mainly plasma volume, was found in patients with portal cirrhosis who had an increased cardiac index, a large portal-systemic collateral circulation, arterial oxygen desaturation and low serum albumin levels. The increased portal venous network did not account for the increased blood volume in portal cirrhosis as patients with extrahepatic portal vein obstruction had virtually normal blood volumes. The low serum albumin levels may in part represent the dilution of a normal amount of circulating albumin by an increased plasma volume. Four patients had low arterial oxygen saturation. Cardiac catheterization data in one patient and studies in two others suggest that the arterial desaturation may be due to the shunting of blood through pulmonary arteriovenous anastomoses. One of these cases is presented in detail. In most patients with portal cirrhosis the increased cardiac output was tolerated without evidence of decomposition. Congestive heart failure was present in one patient reported in detail. As liver function and the clinical status of patients with portal cirrhosis improved, the cardiac output returned toward normal. The mechanism of production of the hyperdynamic circulatory state in portal cirrhosis is unknown. There is profound vasodilatation and the mechanism of this is discussed.

A PORTABLE OXYGEN TENT

recent years the therapeutic use of oxygen has undergone a new trial. Effective methods of administration have been introduced, and a study of the changes in the oxygen content of the arterial blood during treatment has been made. The results indicate that the adequate employment of oxygen in conditions of acute anoxemia is generally followed by clinical improvement, and that an abnormally low arterial oxygen saturation is usually restored to, or near to, the normal value. no report in which oxygen has been effectively administered is a contrary view upheld. Opinions based on experiences with ineffective methods are no longer germane to effective oxygen treatment. Haldane 1 says: In the light of present knowledge it is childish to suppose that as soon as anoxemia is relieved a patient will recover, or that anoxemia is itself a trifling matter if life is not immediately imperiled. If there were only