Hypoxaemia and supplemental oxygen therapy in the first 24 hours after myocardial infarction: the role of pulse oximetry. Comparison of nasal prongs and nasopharyngeal catheter for the delivery of oxygen in children with hypoxemia because of a lower respiratory tract infection. Oxygen administration to hypoxic children in Ethiopia: a randomized controlled study comparing complications in the use of nasal prongs with nasopharyngeal catheters. Postoperative respiratory care: a controlled trial of early and late extubation following coronary-artery bypass grafting. Training with supplemental oxygen in patients with COPD and hypoxaemia at peak exercise. Comparison of the hemodynamic and oxygen transport responses to modified fluid gelatin and hetastarch in critically ill patients: a prospective, randomized trial. Short-term effectiveness of different volume replacement therapies in postoperative hypovolaemic patients. Comparison of nasal prongs with nasal catheters in the delivery of oxygen to children with hypoxia. Physical training with and without oxygen in patients with chronic obstructive pulmonary disease and exercise-induced hypoxaemia.
To assess the incidence and degree of hypoxaemia in patients with acute myocardial infarction and evaluate the nation-wide perception and usage of oxygen therapy.
                Postal survey of all coronary care units (CCU) in England of their use of prescribed oxygen and pulse oximetry. Prospective randomised study of 50 patients presenting within 24 hours of onset of myocardial infarction, half of whom received oxygen therapy. Oxygen saturation (SpO2) as continuously measured by pulse oximetry, and arrhythmias and ST segment changes were recorded on simultaneous 24-hour ambulatory Holter monitors.
                In 53% of UK coronary care units oxygen is not routinely prescribed but in only 3% is a pulse oximeter used to aid management. In patients presenting with acute myocardial infarction the incidence of hypoxaemia (SpO2 < 90%) was 70% and severe hypoxaemia 35% in those not given oxygen, compared with only 27% and 4% in patients given oxygen therapy. The only patient to receive oxygen on clinical grounds had an oxygen saturation of 71%. Severe hypoxaemia (SpO2 < 80%) occurred significantly less often (1 and 7 patients, p < 0.05) in patients given oxygen. There were no differences in arrhythmias or ST segment changes between groups.
                Hypoxaemia occurs frequently in patients in the first 24 hours after acute myocardial infarction. It is effectively and easily treated with supplemental oxygen which can be guided by pulse oximetry. This is rarely done. Measurements of oxygen saturation are therefore justified in all patients to guide oxygen therapy unless there is a decision to give all patients supplemental oxygen: this we believe to be unnecessary. To determine the best method of oxygen delivery for children in developing countries who have hypoxemia caused by acute lower respiratory tract infection.
                One hundred eighteen children between 7 days and 5 years of age with a lower respiratory tract infection and arterial hemoglobin oxygen saturation (Sao2) less than 90% were randomly selected to receive oxygen by nasopharyngeal (NP) catheter (n = 56) or nasal prongs (n = 62). A crossover study to determine the flow rate necessary to achieve an Sao2 of 95% was performed in 60 children.
                One hundred twelve children could be oxygenated by the allocated method; in six oxygenation was poor with either method. The mean duration of therapy was 87.5 hours for the prongs and 94.9 hours for the NP catheter (not significant). The median oxygen consumption was 2142 L for prongs and 1692 L for the NP catheter (not significant). In the crossover study the prongs needed, on average, 26% higher oxygen flow rates than the NP catheter to obtain an Sao2 of 95% (p = 0.003). Complete nasal obstruction was observed in 24 of the children (44%) in the NP catheter group and in 8 (13%) in the prongs group (p < 0.001). Eighteen children died, 11 with NP catheter and 7 with prongs (not significant).
                Because nasal prongs are less prone to complications, and oxygenation in children is equally effective, they are a more appropriate method than the NP catheter for oxygen delivery to children in developing countries with acute lower respiratory tract infections. Oxygen administration is one of the most important therapeutic interventions for a child with severe acute lower respiratory tract infection (ALRI). Inexpensive and efficient methods of oxygen administration are highly desirable in hospitals in developing countries. The objectives of this study were to compare the frequency and nature of complications when nasopharyngeal catheters or nasal prongs are used to deliver oxygen. One hundred and twenty-one children between the ages of 2 weeks and 5 years with hypoxia due to ALRI were randomized to receive oxygen via a catheter (61 children) or via nasal prongs (60 children). The two groups were similar in terms of diagnoses, clinical severity, oxygen saturation on admission and case fatality rates. There was no difference in the incidence of hypoxaemic episodes between the two groups. The oxygen flow rates required on the day of admission for adequate oxygenation (SaO2 > 90%) ranged from 0.8 litres per minute to 1.2 litres per minute. The required oxygen flow rate decreased during the course of treatment. Mucus production was more of a problem in the catheter group, and nasal blockage, intolerance of the method of oxygen administration and nursing effort were generally higher amongst the catheter group, but none of these differences was significant. Ulceration or bleeding of the nose was significantly more common in the catheter group (19.7% vs 6.7%, p < 0.05). Abdominal distension and nasal perforation were not seen in either group. This study suggests that nasal prongs are safer, more comfortable and require less nursing expertise than nasopharyngeal catheters for administration of oxygen to children. Sequelae of early versus late extubation of the trachea in patients following coronary-artery bypass grafting were compared prospectively in 38 patients randomly assigned to one of the two groups. The times to extubation were 2 +/- 2 and 18 +/- 3 hours after operation for the two groups. Comparisons were made between groups for the following five variables: time spent in the intensive care unit; drug utilization in the intensive care unit; cardiopulmonary morbidity; hemodynamic performance; patient stress (plasma norepinephrine levels). The anesthetic technique consisted of induction with thiopental, nitrous oxide, and halothane, followed by maintenance with nitrous oxide and halothane. Pancuronium was the only muscle relaxant administered. Patients whose tracheas were extubated early had muscle relaxants reversed prior to the application of extubation criteria. There was no significant difference between the groups in times spent in the intensive care unit, hemodynamic performances, or plasma norepinephrine levels; however, the patients whose tracheas were extubated early received less morphine and diazepam and suffered significantly less cardiopulmonary morbidity. Supplemental oxygen has acute beneficial effects on exercise performance in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to investigate whether oxygen-supplemented training enhances the effects of training while breathing room air in patients with severe COPD. A randomized controlled trial was performed in 24 patients with severe COPD who developed hypoxaemia during incremental cycle exercise (arterial oxygen saturation (Sa,O2) <90% at peak exercise). All patients participated in an in-patient pulmonary rehabilitation programme of 10 weeks duration. They were assigned either to general exercise training while breathing room air (GET/RA group: forced expiratory volume in one second (FEV1) 38% of predicted; arterial oxygen tension (Pa,O2) 10.5 kPa at rest; Pa,O2 7.3 kPa at peak exercise), or to GET while breathing supplemental oxygen (GET/O2 group: FEV1 29% pred; Pa,O2 10.2 kPa at rest; Pa,O2 7.2 kPa at peak exercise). Sa,O2 was not allowed to fall below 90% during the training. The effects on exercise performance while breathing air and oxygen, and on quality of life were compared. Maximum workload (Wmax) significantly increased in the GET/RA group (mean (SD) 17 (15) W, p<0.01), but not in the GET/O2 group (7 (25) W). Six minute walking distance (6MWD), stair-climbing, weight-lifting exercise (all while breathing room air) and quality of life significantly increased in both groups. Acute administration of oxygen improved exercise performance before and after training. Training significantly increased Wmax, peak carbon dioxide production (V'CO2) and 6MWD while breathing oxygen in both groups. Differences between groups were not significant. Pulmonary rehabilitation improved exercise performance and quality of life in both groups. Supplementation of oxygen during the training did not add to the effects of training on room air. To compare the hemodynamic and oxygen transport responses to a rapid (< 10-min) infusion of 500 mL of modified fluid gelatin (group A) or hydroxyethyl starch (group B) in patients suffering from acute hypovolemia.
                Prospective, randomized, noncrossover study.
                University hospital, general intensive care unit.
                Twenty-eight patients with hypovolemia mechanically ventilated for concurrent acute respiratory failure.
                Patients were mechanically ventilated. Pulmonary and femoral artery catheters were used for hemodynamic monitoring.
                Hemodynamic and oxygen transport variables were determined at baseline, 15 mins, and 30 mins after the infusion of each fluid. In both groups pulmonary artery occlusion pressure, stroke volume, and cardiac index significantly increased. In neither group did heart rate decrease. Oxygen delivery increased significantly in group A patients but not in group B patients. This result was due to greater hemodilution in group B patients.
                There are no significant differences in the hemodynamic responses to hydroxyethyl starch or modified fluid gelatin. The hemodynamic and oxygen transport effects of artificial colloid solutions may not be entirely predictable and should be monitored in critically ill patients. To examine the kinetics of volume loading with crystalloid and colloid infusions in critically ill patients after major surgery, using the pulse contour cardiac output (PiCCO) monitoring technique.
                This prospective, randomized, multicentre study of 11 ICUs involved 200 mixed postoperative hypovolaemic patients (50 patients per group) in Hungary. Patients received 10 ml kg of lactated Ringer's solution, succinylated gelatin 4% w/v, 130/0.4 hydroxyethyl starch 6% w/v (HES) or human albumin 5% w/v over 30 min. A complete haemodynamic profile was obtained at 30, 45, 60, 90 and 120 min after baseline. The peak haemodynamic effects, the 120 min changes compared with baseline, the area under the curve (AUC) for the haemodynamic parameters over 120 min and the haemodilution effect of the solutions were analysed. The primary outcome was to compare the AUCs and the secondary outcome was to evaluate the haemodynamic changes at 120 min.
                There were significant differences in the AUCs of the haemodynamic parameters between colloids and lactated Ringer's solution in the cardiac index and global end-diastolic volume index (GEDVI); human albumin vs. lactated Ringer's solution in stroke volume variation (SVV); and succinylated gelatin, HES vs. lactated Ringer's solution in the oxygen delivery index (DO2I). Colloid infusions (mainly HES and human albumin) at 120 min caused significant changes in central venous pressure, cardiac index, GEDVI, SVV, DO2I and central venous oxygen saturation compared with baseline. The haemodilution effect was significantly greater in colloids vs. lactated Ringer's solution.
                In postoperative hypovolaemic patients, lactated Ringer's solution can significantly improve haemodynamics at the end of volume loading, but this effect completely disappears at 120 min. Ten millilitres per kilogram of colloid bolus (especially HES) improved the haemodynamics at 120 min; however, this was by only 5-25% compared with baseline. The colloids caused significantly larger AUCs than lactated Ringer's solution, but only in the cardiac index, GEDVI and DO2I, plus human albumin in the SVV. Efficient, inexpensive, and safe methods of oxygen delivery are needed for children with severe pneumonia in developing countries. The objective of this study was to estimate the frequency of complications when nasal catheters or nasal prongs are used to delivery oxygen. Ninety-nine children between 2 weeks and 5 years of age with hypoxia were randomized to receive oxygen via nasal catheter (49 children) or nasal prongs (50 children). There was no difference in the incidence of hypoxaemic episodes or in the oxygen flow rates between the two groups. Mucus production was more of a problem in the catheter group. Nasal blockage, intolerance to the method of administration, and nursing effort were generally higher amongst the catheter group, but these differences were not significant, except for nursing effort, when all age groups were analysed together. A randomized, controlled, single-blind study was performed on 20 patients with chronic obstructive pulmonary disease and exercise-induced hypoxaemia. Ten patients each were randomly assigned to one of two groups, one training with air and the other training with oxygen. There were no significant differences between the groups regarding values measured prior to the study. The patients trained 3 times per week for 30 minutes each time for a duration of 8 weeks. The training consisted of interval walking on a treadmill (intensity set according to Borg ratings) with either air or oxygen administered through a nasal cannula at a rate of 5 l/min. Training significantly improved the 6-minute walking distance by 20% and 14% in the air and oxygen group, respectively, when the patients were tested on air. In the same test the air group significantly decreased Borg ratings for perceived exertion. Borg ratings for dyspnoea and perceived exertion significantly decreased in the oxygen group when they were tested on oxygen. It was concluded that oxygen supplementation did not further improve the training effect, compared with training with air, in patients with chronic obstructive pulmonary disease and exercise-induced hypoxaemia.
NP and NPC seem to be similar in effectiveness and safety when used in patients with LRTI. There is no single clinical sign or symptom that accurately identifies hypoxaemia. Studies identifying the most effective and safe oxygen delivery method are needed.