摘要:

This study compared radiographic measurements of regional lung volume with corresponding physiologic measurements. The database included 48 normal, supine adults who had previously undergone spirometry and helium-dilution lung volume measurements to determine physiologic functional residual capacity (G-FRC) and total lung capacity (G-TLC). Chest x-rays had also been obtained for these subjects at functional residual capacity and total lung capacity.To calculate radiographic lung volumes at functional residual capacity and total lung capacity (R-FRC and R-TLC, respectively), we traced the lung outline from the chest x-ray, and digitized each outline. We then calculated total and regional lung volumes, using equations previously derived from computed tomographic scans. R-FRC and R-TLC were closely correlated (r = 0.973, maximum SEE 6.8%) with G-FRC and G-TLC, whether or not separate equations were used for regions below the diaphragm. Using only maximum anteroposterior diameter reduced the r-value to 0.957 (SEE 9.6%). The accuracy of our method of radiographic measurement of regional lung volume was validated by the concurrence between the physiologic and radiographic measurements.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Gravity has significant effects on the microvascular pressure in the lungs and thus on regional fluid filtration in the lungs. Below the level of the heart, gravity increases the microvascular pressure with respect to the left atrial pressure; above the level of the heart, microvascular pressure is less than atrial pressure. To assess the contribution of gravity to fluid filtration in the lungs independent of left-heart filling pressure, the distribution of lung volume above and below the left atrium must first be determined.To permit calculation of the contribution of hydrostatic pressure per unit of lung volume, 26 computed tomographic scans of the entire chest were traced and measured, marking the level of the center of the left atrium (LAL) on each slice. The intrathoracic volume above and below the left atrium was measured by multiplying scan slice thickness by the area of the lung above or below the LAL measured on each scan slice. On 16 scans, intrathoracic volumes of 1-cm horizontal layers of lung above and below the LAL were also calculated by measuring corresponding segments of the transverse scan slices. The calculations indicate that in the supine posture more lung is dependent than when upright, and that elevation of a patient to 30° reduces the volume of lung below the LAL nearly as much as does the upright posture.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

A prospective microbiologic evaluation of the urine was conducted on 100 catheterized ICU patients. Eight subjects had positive initial bladder urine cultures and were eliminated from further study. The remaining 92 patients were catheterized for up to 22 days, mean 4.8 ± 4.3 (SD). During the first 5 days, 57 (62%) patients completed the surveillance protocol; seven (12.3%) of these had bladder bacteriuria. Of 20 patients with positive urine cultures, six had microorganisms in the collection bag urine alone. The remaining 14 had organisms both in the bladder and in the bag urine. The urine collection bag was the apparent source of microorganisms in the bladder urine in only three cases. The daily incidence of new cases and the cumulative rate of bladder bacteriuria remained below 7% and 22%, respectively, during the first week of catheterization. These rates are similar to those previously reported for various other patient groups outside the ICU setting. Frequent microbiologic monitoring of the urine seems to be unnecessary for most ICU patients because of the short duration of catheterization.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The hemodynamic effects of octopamine (OCT) were studied before and during dopamine (DA) infusion in six normal dogs. Before OCT infusion, DA significantly increased cardiac index (CI) from 3.24 ± 0.20 to 4.90 ± 0.30 L/min - m2 and significantly decreased systemic vascular resistance index (SVRI) from 3700.2 ± 212.5 to 2618.3 ± 156.6 dyne · sec/cm5 · m2, without changing heart rate. During OCT infusion, DA failed to increase CI or decrease SVRI; however, it significantly increased heart rate from 153.3 ± 12.9 to 183.0 ± 17.0 beat/min. This suppression of a DA-related increase in cardiac output may explain why DA is ineffective in those septic patients with elevated plasma OCT levels.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Of 142 critically ill patients undergoing pulmonary artery catheter (PAC) insertion, 1.4% suffered pneumothorax and 7.7% experienced arterial puncture during central venous access. Catheterization was successful in all cases; however, 8.4% of patients required special maneuvers for pulmonary artery cannulation. The 52.3% incidence of cardiac arrhythmias during PAC insertion was primarily due to ventricular arrhythmia (VA), which was more common among patients with complicated myocardial infarction (p<.01) and less common in patients with sepsis (p< .05). The development of VA was significantly related to the duration of PAC insertion. Our study suggests that PAC placement carries certain risks and complications which should be weighed against the advantages of a PAC in each patient.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The development of pneumonia was monitored in head-trauma patients requiring mechanical ventilation. Of the 66 patients studied, 15 (23%) developed pneumonia within 14 days after ICU admission. In each case the diagnosis was based on x-ray evidence and at least two of the following: increased white blood cell count, increased fever, and/or increased sputum production with a predominant organism on the sputum stain. Coagulase-positive Staphylococcus aureus was the most common etiologic agent. There was no difference in the occurrence of pneumonia between patients treated with no steroids or with low, moderate, or high steroid doses. Although there was an association between thiopental use and the development of pneumonia, dexamethasone treatment was not a significant risk factor in the development of pneumonia in this patient population.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Ten anesthetized, paralyzed dogs were ventilated at 10 breath/min and 100 cycle/min with a valveless ventilator. When fresh respiratory gas was supplied at the carina or insufflated into the bronchi, there was a significant (p < .05) reduction in Paco2, which was maximal during high-frequency ventilation (HFV) with twice normal minute volume. There was no statistically significant advantage in using a more complicated system for bronchial insufflation compared with supplying the fresh gas through a single tube near the carina. The improvement in ventilation and oxygenation during HFV with gas at the carina was reduced markedly when normal lungs were injured by oleic acid.Thus, when peak airway pressure was minimized during HFV, there was a further improvement in gas exchange without an appreciable increase in airway pressure when the gas was supplied at the carina.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

High-frequency ventilation (HFV) has been suggested as an alternative to standard positive-pressure ventilation with positive end-expiratory pressure (PPV/ PEEP) in the treatment of infants with hyaline membrane disease. To assess the relative safety and efficacy of HFV, we compared standard PPV to HFV delivered by oscillation (HFO) and HFV delivered by a flow interrupter (HFFI) in a previously validated preterm baboon model of hyaline membrane disease. At necropsy, the livers of several animals were unexpectedly found to have severe fatty change and/or cytoplasmic vacuolization and edema. There was a strong correlation between use of HFO and the development of liver lesions. The hepatic lesion may reflect decreased cardiac output with a concomitant fall in splenic perfusion and/or alterations in normal intrathoracic pressure that increase resistance in the hepatic vasculature. Although the etiology cannot be determined precisely, these data suggest the potential for nonpulmonary complications of HFV in the immature newborn and mandate further investigation before its widespread clinical application.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Records of 140 infants younger than 2 yr of age who had undergone open heart surgery were studied to evaluate the duration of postoperative mechanical ventilation (MV), to determine the relationship between prolonged MV and mortality, and to identify variables predisposing the patient to prolonged MV. MV was required beyond the first postoperative day in 56 infants, and was prolonged for at least 7 days in 19 infants. Mortality was approximately the same (16% to 17%) whether or not MV was required for more than 7 days. Preoperative and intraoperative variables associated with longer MV included younger age, longer cardiopulmonary bypass time, longer aortic cross-clamp time, and preoperative MV. Multiple predisposing factors increased the probability of prolonged MV. Postoperative variables including premature extubation and a second surgical procedure also were associated with prolonged MV. The consequences of prolonged MV may be minimized by early nutritional support, aggressive surveillance for treatable complications, and avoidance of premature extubation.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Severity of illness in 293 pediatric ICU patients was assessed by a daily estimate of ICU survival. The probability of nonsurvival was obtained by logistic regression analysis, using physiologic stability index (PSI) values from previous days as time-dependent covariates. Only PSI values from the previous 2 days gave statistically significant predictions of short-term (less than 24 h) outcome. When the prediction model derived from these data was tested prospectively on a separate set of 345 pediatric patients, there was excellent agreement between observed and predicted short-term mortality. Receiver operating characteristic curves for the 345 patients were statistically equivalent to those originally derived for the 293 patients, and this prediction model had significantly (p< .025) more accuracy than prediction based on admission PSI. These results indicate that this model for daily risk assessment is statistically reliable and objective, as verified against eventual outcome. In the 345 patients, ICU mortality ! was predicted with 89% sensitivity and 91 % specificity. This prediction model may be used to stratify patient groups for clinical studies, or identify very low-risk patients for potential early ICU discharge.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID