Arterial Blood Gases In Patients Research Articles

Prognostic factors in methanol poisoning

The aim of this study was to assess the clinical and laboratory factors in methanol poisoned patients to determine the prognosis of their toxicity. This survey was done as a prospective cross-sectional study in methanol-poisoned patients in Loghman-Hakim hospital poison center during 9 months from October 1999-June 2000. During this time 25 methanol-poisoned patients were admitted. The mortality rate was 12 (48%). Amongst survivors, three (23%) of the patients developed blindness due to their poisoning and the other 10 (77%) fully recovered without any complication. The mortality rate in comatose patients was nine (90%) while in non-comatose patients it was three (20%) (P<0.001). There was a significant difference in mean pH in the first arterial blood gas of patients who subsequently died (6.82+/-0.03) and survivors (7.15+/-0.06) (P<0.001, M-W). The mean time interval between poisoning and ED presentation in deceased patients were (46+/-15.7) hours, in survived with sequelae were (16.7+/-6.7) and in survived without sequelae were (10.3+/-7.2) hours (P<0.002, K-W). We found no significant difference between the survivors versus the patients who died regarding methanol. Simultaneous presence of ethanol and opium affected the outcome of the treatment for methanol intoxication favourably and unfavourably, respectively. In our study, poor prognosis was associated with pH<7, coma on admission and >24 hours delay from intake to admission.

Effects of rac‐albuterol on arterial blood gases in patients with stable hypercapnic chronic obstructive pulmonary disease

Many patients with chronic obstructive pulmonary disease (COPD) are treated with high dose beta(2)-adrenoceptor agonists, which can increase ventilation/perfusion mismatching, and tremor and cardiac output, thereby increasing oxygen uptake and carbon dioxide output (VCO(2)). Patients with severe COPD and hypercapnia may be unable to increase ventilation in response to increased VCO(2), in which case arterial carbon dioxide tension (P(a)CO(2)) may rise. Our aim was to determine whether high dose nebulized rac-albuterol could increase P(a)CO(2) in patients with COPD, limited bronchodilator reversibilty and hypercapnia. We compared 10 mg and 400 microg rac-albuterol, given in two doses 1 h apart on nonconsecutive days, in a double-blind randomized crossover study in 14 patients with severe COPD. P(a)CO(2), arterial oxygen tension (P(a)O(2)) and heart rate were measured over 120 min and change from baseline was plotted against time to obtain an area under the curve. Mean P(a)CO(2) fell slightly over 120 min, with no difference between treatments (0.03 kPa h(-1) (95% confidence interval 0.02, 0.04)) and only three subjects had an increase in P(a)CO(2) after high dose rac-albuterol. High dose rac-albuterol caused a greater fall in P(a)O(2)[0.1 kPa h(-1) (95% confidence interval 0, 0.2)] and increase in heart rate than the low dose, although the differences were small. Under stable conditions most subjects with severe COPD and hypercapnia will have a fall in P(a)CO(2) and P(a)O(2) following 10 mg rac-albuterol, suggesting that they maintain capacity to respond to any increase in VCO(2) and prevent a rise in P(a)CO(2).

Pulmonary complications in patients with chronic obstructive pulmonary disease following transthoracic esophagectomy

To investigate the incidence of various types of postoperative pulmonary complications (POPCs) and to evaluate the significance of perioperative arterial blood gases in patients with esophageal cancer accompanied with chronic obstructive pulmonary disease (COPD) after esophagectomy. Three hundred and fifty-eight patients were divided into POPC group and COPD group. We performed a retrospective review of the 358 consecutive patients after esophagectomy for esophageal cancer with or without COPD to assess the possible influence of COPD on postoperative pulmonary complications. We classified COPD into four grades according to percent-predicted forced expiratory volume in 1 s (FEV1) and analyzed the incidence rate of complications among the four grades. Perioperative arterial blood gases were tested in patients with or without pulmonary complications in COPD group and compared with POPC group. Patients with COPD (29/86, 33.7%) had more pulmonary complications than those without COPD (36/272, 13.2%) (P < 0.001). Pneumonia (15/29, 51.7%), atelectasis (13/29, 44.8%), prolonged O(2) supplement (10/29, 34.5%), and prolonged mechanical ventilation (8/29, 27.6%) were the major complications in COPD group. Moreover, patients with severe COPD (gradeIIB, FEV1<50% of predicted) had more POPCs than those with moderate(gradeIIA, 50%-80% of predicted) and mild (gradeI> or =80% of predicted) COPD (P < 0.05). PaO(2) was decreased and PaCO(2) was increased in patients with pulmonary complications in COPD group in the first postoperative week. The criteria of COPD are the critical predictor for pulmonary complications in esophageal cancer patients undergoing esophagectomy. Severity of COPD affects the incidence rate of the pulmonary complication, and percent-predicted FEV1 is a good predictive variable for pulmonary complication in patients with COPD. Arterial blood gases are helpful in directing perioperative management.

Correlation of simultaneously obtained capillary, venous, and arterial blood gases of patients in a paediatric intensive care unit

Aims: To investigate the correlation of pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), base excess (BE), and bicarbonate (HCO3) between arterial (ABG), venous (VBG), and...

Effects of breath training pattern “end-lnspiratory pause” on respiratory mechanics and arterial blood gas of patients with COPD

Objective In order to explore the mechanism of Chinese traditional breath training, the effects of end-inspiratory pause breathing (EIPB) on the respiratory mechanics and arterial blood gas were studied in patients with chronic obstructive pulmonary disease (COPD).

Association of oral almitrine and medroxyprogesterone acetate: effect on arterial blood gases in chronic obstructive pulmonary disease

Almitrine (A) and medroxyprogesterone acetate (MA) given separately improve arterial blood gases in some patients with chronic obstructive pulmonary disease (COPD); the aim of this study was to assess the effect of the two drugs given together. Forty-eight patients with irreversible COPD and hypoxaemia were prospectively enrolled into a 14-day run-in period and received single-blind oral treatment with double placebo. Patients whose P aO 2remained stable (less than 10% change; n=29, 25 males, mean age 65·6 years) were included in a 14-day active treatment period and randomly assigned to three groups. They received double-blind oral treatment with: A (50 mg bid, group A, n=10); MA (20 mg tid, group MA, n=9); A (50 mg bid) and MA (20 mg tid, group A+MA, n =10). Anthropometric and spirometric measurements were similar in the three groups and so were the arterial blood gas values at the beginning and the end of the run-in period. At the end of the active treatment period, blood gas changes (mean± SE) were significantly different between groups ( P<0·05, Kruskal–Wallis test), with improvement in both hypoxaemia and hypercapnia in group A+MA only: Δ P aO 2=7·4±1·9 mmHg, Δ P aCO 2= −5·1±1·7 mmHg ( P<0·05, Wilcoxon test). In short-term treatment, the association of A and MA is more efficient than either drug alone at improving arterial blood gases in COPD patients.

Neural Network in the Clinical Diagnosis of Acute Pulmonary Embolism

The purpose of this investigation was to test the hypothesis that computer-based pattern recognition can accurately assess the likelihood of acute pulmonary embolism (PE) based on readily obtainable clinical characteristics. Data were obtained from 1,213 patients who participated in the collaborative study of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED). Characteristics of the history, physical examination, electrocardiograph, chest radiograph, and arterial blood gases of patients with suspected acute PE were presented to a back propagation neural network. The 1,213 patients were divided into training set A (n = 606) and test set B (n = 607). These groups were then reversed into training set B (n = 607) and test set A (n = 606). A receiver operating characteristic (ROC) curve was constructed from PIOPED clinical assessment, and from neural network clinical assessment in groups A and B. Areas under the respective ROC curves were 0.7450, 0.7477, and 0.7324. All differences were not significant. Areas under ROC curves for PIOPED clinical assessment combined with ventilation/perfusion (V/Q) scan results were compared with neural network clinical assessment combined with V/Q scan results in groups A and B. The respective ROC areas were 0.8324, 0.8203, 0.8496 (all differences not significant). These data show that neural networks were able to predict the clinical likelihood of PE with an accuracy comparable to experienced clinicians.

Sequential treatment with low dose almitrine bismesylate in hypoxaemic chronic obstructive airways disease

Daily dose schedules of 100-200 mg of almitrine bismesylate improve arterial blood gases in patients with hypoxaemic chronic obstructive airways disease (COPD) but dose related side effects are evident. In the present study, daily doses approximately half of those previously used were employed in a randomised double blind manner in 85 patients (age 35-79 years) with hypoxaemic COPD. After a one month period to check stability of arterial blood gases, patients were allocated to almitrine (A) or placebo (P) using an unequal code (60% A, 40% P). Tablets, 50-100 mg daily were stopped for one month after 3, 6 and 9 months to counteract drug accumulation. 50 patients in group A and 35 in group P were comparable on entry; mean age 65 (SD = 8) yrs., Pao2 7.8 (0.7) kPa (58.3 (5.0) mmHg), PaCO2 5.8 (0.8) kPa (43.2 (6.0) mmHg), forced expiratory volume in one second--FEV1 0.89 (0.25) l and 6 minute walking distance 296 (97) metres. The improvement in baseline PaO2 values was the same 0.8-1.3 kPa (6-9.8 mmHg) as with previous higher dose therapy. Approximately one third of patients did not respond, defined as PaO2 elevation > 0.67 kPa (5 mmHg). The sequential dosing scheme stabilised blood levels of almitrine within the therapeutic range of 280-300 ng.ml-1. After withdrawal of therapy arterial blood gases and spirometry reverted to pre-treatment levels, suggesting no permanent reversal of pathophysiology. Dose related side effects of breathlessness, indigestion and peripheral neuropathy were not observed. Nerve conduction studies revealed no difference in peripheral nerve dysfunction in hypoxaemic COPD between active and placebo therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial blood gases in patients with acute head injury at the accident site and upon hospital admission

Prior to the start of supportive therapy at the site of the accident, arterial blood samples from 47 patients with acute head injury were taken for blood gas analysis. At the same time, the degree of unconsciousness was assessed using the Glasgow-Coma-Scale. After transport to the hospital, arterial blood gases and the level of unconsciousness were again determined. A very close correlation was found between the initial depth of unconsciousness and the degree of hypercapnia (R = -0.90). Patients with head injury and other multiple injuries did not differ in this report (R = -0.95) from those with isolated head injury. The correlation between PaO2 and the degree of unconsciousness was less well defined, and the results showed a greater degree of scatter (R = 0.54). The acidosis observed resulted mainly from the rise in PaCO2. The absence of any correlation between the base excess and the Glasgow-Coma-Scale levels (R = -0.27) makes a common metabolic derangement unlikely. As a result of intubation and controlled ventilation, the hypercapnia of the comatose patients had been corrected, and a correlation could no longer be found between the Glasgow-Coma-Scale level and the PaCO2. In order to avoid hypoventilation, which carries with it the danger of a rise in intracranial pressure, all patients with severe head injury should be intubated and ventilated as soon as possible after the accident.

Effects of Oral Morphine on Breathlessness and Exercise Tolerance in Patients with Chronic Obstructive Pulmonary Disease

Previous studies have shown that opiates increase the maximal external work performed at exhaustion in patients with chronic obstructive pulmonary disease (COPD). The mechanism responsible for this improvement in exercise tolerance is unknown. The purpose of this study was to determine the effects of an oral morphine solution (0.8 mg/kg) on the exercise tolerance, perception of dyspnea, and arterial blood gases of patients with COPD. Thirteen eucapnic patients with stable COPD (FEV1 = 0.99 +/- 0.48) underwent duplicate incremental cycle ergometer tests to exhaustion (Emax) after the ingestion of placebo and after the ingestion of morphine. After the ingestion of morphine, the maximal workload increased by 18% (p less than 0.001) and the VO2 increased by 19.3% (p less than 0.001). Ten of the 13 patients had a higher ventilation at Emax after morphine ingestion. Despite the higher ventilation at Emax after morphine, the mean Borg score was not significantly higher. At Emax after morphine ingestion, the PaO2 (65.8 +/- 11.6 mm Hg) was significantly lower and the PaCO2 (43.5 +/- 8.3 mm Hg) was significantly higher than at Emax after placebo (71.9 +/- 15.5 and 38.3 +/- 8.5, respectively). When data at the highest equivalent workload were analyzed, the ventilation and the Borg scores were significantly lower, whereas the VO2 and VCO2 were comparable. From this study, we conclude that the administration of opiates can substantially increase the exercise capacity of patients with COPD. The improved exercise tolerance appears to be related to both a higher PaCO2 resulting in lowered ventilation requirements for a given workload and also to a reduced perception of breathlessness for a given level of ventilation.

Sedation and cerebral angiography. The effects of pentazocine and midazolam on arterial carbon dioxide tension.

A study of the effects of sedation on arterial blood gases in patients undergoing cerebral angiography was performed. Twenty-one patients received pentazocine (30 mg) and midazolam (5-22.5 mg) and arterial carbon dioxide and oxygen tensions were measured from radial artery samples before and during the procedure. A statistically significant rise in arterial carbon dioxide tension was demonstrated. It is suggested that this may cause a rise in intracranial pressure by increasing cerebral blood flow in a group of patients in whom there is a high incidence of raised intracranial pressure. The clinical significance of this increase in arterial carbon dioxide tension is discussed.

Effect of desipramine on control of ventilation and depression scores in patients with severe chronic obstructive pulmonary disease

Decreased ventilatory responses to carbon dioxide (CO 2) correlate with elevated scores on tests for depression in normal subjects and with episodes of endogenous depression in psychiatric patients. Patients with severe chronic obstructive pulmonary disease (COPD) frequently develop resting hypercapnia due to impaired ventilatory mechanics or drive, and may also have elevated scores on tests for depression. Tricyclic antidepressant drugs can improve ventilatory mechanics and possibly drive. We hypothesized that antidepressant drugs might enhance ventilatory drive and improve arterial blood gases in patients with severe COPD and that these improvements might correlate with improvement in depression scores. Therefore, we studied the effects of desipramine versus placebo on spirometry, resting arterial blood gases, hypercapnic ventilatory and mouth occlusion pressure responses, and scores on the Beck and Zung self-rated depression scales. In our patients the resting arterial CO 2 (P aCO 2) was found to depend almost equally on ventilatory mechanics and drive. In addition, patients with higher depression scores tended to have a lower P aCO 2 when the severity of airways obstruction was taken into consideration. In a 16-week, double-blind, crossover comparison of desipramine with placebo, both treatments led to significant improvement in depression scores. Desipramine had no effects on resting P aCO 2, spirometry, or ventilatory control.

The Influence of Cardiovascular Function on Gas Exchange

Alterations in cardiovascular function may play a major role in determining pulmonary gas exchange and thus significantly influence the gas composition of the arterial blood. The influence of the cardiovascular system may be exerted through changes in the PvO2 or by directly altering the distribution of ventilation and blood flow in the lung. Although this relationship is difficult to clinically assess, it must always be considered when interpreting changes in the arterial blood gases of patients with cardiopulmonary dysfunction.

Diazepam and Meperidine on Arterial Blood Gases in Patients with Chronic Obstructive Pulmonary Disease

Arterial blood gases were not significantly altered by 0.15 mg/kg intravenous dose of diazepam in patients with chronic obstructive lung disease. The PalphaO-2 was significantly reduced and the P-alphaCO-2 increased after administration of 1.5 mg/kg meperidine intravenously and the combination of 1.5 mg/kg meperidine with 0.15 mg/kg diazepam. Diazepam did not, however, significantly increase the ventilatory depression induced by meperidine. Therefore, 0.15 mg/kg diazepam intravenously causes no ventilatory depression by meperidine in patients with chronic obstructive lung diseases.

The effects of an ultrasonic aerosol on pulmonary mechanics and arterial blood gases in patients with chronic bronchitis.

Spirometric and arterial blood gas measurements were made in 26 patients with chronic bronchitis before and after inhaling an ultrasonic mist of 0.45 per cent sodium chloride solution. A significant decrease in one-second forced expiratory volume (FEV1) and vital capacity (VC) was noted after inhalation of ultrasonic mist for 15 minutes. Thirty per cent of these patients also had a decrease in arterial oxygen tension (PaO2) of 8 mm Hg or more. When a bronchodilator aerosol was inhaled before the ultrasonic mist, decrease in FEV1 and VC was not seen, but a significant decrease in PaO2 was noted. The decrease in PaO2 suggested that an undesirable change occurred in the ventilation-perfusion relationships of the lungs after bronchodilator therapy.

The effect of oxygen breathing on arterial blood gases in patients with chronic airway obstruction living at 5,200 feet.

The effect of oxygen breathing on arterial blood gases in patients with chronic airway obstruction living at 5,200 feet.