摘要:

Objective:To determine whether three hydrophobic and hygroscopic heat and moisture exchangers (HMEs) retain their heating and humidifying properties (assessed by psychrometric measurements of absolute humidity, relative humidity, and tracheal temperature) for 48 hrs without any drop in their bacteriologic efficiency.Design:Prospective randomized clinical trial.Patients:Sixty-one consecutive unselected mechanically ventilated intensive care unit patients.Interventions:Patients were randomly allocated to one of the three HMEs studied (Hygrobac-Dar from Mallinckrodt, n = 21; Humid-Vent from Gibeck, n = 20; and Clear-Thermal from Intersurgical, n = 20).Measurements and Main Results:Hygrometric parameters were measured by psychrometry after 3, 24, and 48 hrs of use. Peak airway pressure was recorded every 6 hrs and averaged over 24 hrs. Bacterial colonization of both patients and circuits was studied. Patients in all three groups were similar in terms of age, indications for, and overall duration of mechanical ventilation. Tracheal tube occlusion never occurred. Hygrometric data included 371 measurements whereas bacteriologic data included >700 samples and cultures. The Hygrobac-Dar HMEs gave a significantly higher absolute humidity whatever the time of measurement (3, 24, or 48 hrs) than the other two HMEs (p< .001). The Clear-Thermal HMEs gave the poorest hygrometric parameters (p< .01); five of them were replaced prematurely (24 hrs) because the absolute humidity was <25 mg H2O/L. This did not occur for the other HMEs. Mean peak airway pressures were identical in the three groups. The bacterial colonizations of both patient and circuit were similar (and negligible for circuits) for all three groups.Conclusion:Some HMEs may be used safely for 48 hrs without change. However, this does not pertain to every brand of HME. Objectivein vivoevaluation of their humidifying performances is decisive before extending their duration of use.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To evaluate if the preexistant filling state, assessed by right atrial pressure (RAP), pulmonary artery occlusion pressure (PAOP), and right ventricular end-diastolic volume index (EDVI), would define the subsequent hemodynamic effects of increases in airway pressure (Paw).Design:Prospective open clinical study.Setting:Postoperative intensive care unit, university hospital.Patients:Twenty-two consecutive ventilator-dependent patients with mild to severe acute lung injury with Murray scores (scoring infiltrates on chest radiograph, oxygenation index, lung compliance, and the level of positive end-expiratory pressure) ranging from 0.5 to 3.0 without history of preexisting cardiopulmonary disease.Interventions:Paw varied during apnea from 0 to 10, 20, and 30 cm H2O using inspiratory hold maneuvers of 15 secs.Measurements and Main Results:Cardiac index and right ventricular ejection fraction were measured by the thermodilution technique. We made measurements in triplicate using manual injection of iced saline. Right ventricular volumes were calculated.Increasing Paw induced variable changes in cardiac index among subjects (+6% to −43% change from baseline 0 cm H2O Paw values), which correlated with percentage changes in both stroke index (r2= .89) and right ventricular EDVI (r2= .75), whereas heart rate and right ventricular ejection fraction did not change. The change in cardiac index from 0 to 30 cm H2O Paw correlated with baseline values for RAP, PAOP, and right ventricular EDVI (r2= .68, .43, and .34, respectively,p< 0.01). Increases in RAP correlated with lung compliance if baseline RAP was >10 mm Hg but did not if it was ≤10 mm Hg. Similarly, patients with baseline RAP ≤10 mm Hg had a greater decrease in cardiac index than patients with a RAP >10 mm Hg (for 30 cm H2O Paw: −30% ± 9% vs. −8% ± 7%,p< .01).Conclusions:Apneic positive Paw decreased cardiac output mainly by reducing venous return. From the investigated filling variables, RAP was most sensitive in predicting the hemodynamic response, followed by PAOP and right ventricular EDVI. Patients with RAP ≤10 mm Hg, if subjected to aggressive positive pressure ventilation, are at risk of hemodynamic deterioration and organ hypoperfusion.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To investigate the additional effect of incentive spirometry to chest physiotherapy to prevent postoperative pulmonary complications after thoracic surgery for lung and esophageal resections.Design:Randomized controlled trial.Setting:University hospital, intensive care unit, and surgical department.Patients:Sixty-seven patients (age, 59 ± 13 yrs; forced expiratory volume in 1 sec, 93% ± 22% predicted) undergoing elective thoracic surgery for lung (n = 40) or esophagus (n = 27) resection.Interventions:Physiotherapy (breathing exercises, huffing, and coughing) (PT) plus incentive spirometry (IS) was compared with PT alone.Measurements and Main Results:Lung function, body temperature, chest radiograph, white blood cell count, and number of hospital and intensive care unit days were all measured. Pulmonary function was significantly reduced after surgery (55% of the initial value) and improved significantly in the postoperative period in both groups. However, no differences were observed in the recovery of pulmonary function between the groups. The overall score of the chest radiograph, based on the presence of atelectasis, was similar in both treatment groups. Eight patients (12%) (three patients with lobectomy and five with esophagus resection) developed a pulmonary complication (abnormal chest radiograph, elevated body temperature and white blood cell count), four in each treatment group. Adding IS to regular PT did not reduce hospital or intensive care unit stay.Conclusions:Pulmonary complications after lung and esophagus surgery were relatively low. The addition of IS to PT did not further reduce pulmonary complications or hospital stay. Although we cannot rule out beneficial effects in a subgroup of high-risk patients, routine use of IS after thoracic surgery seems to be ineffective.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:In animal studies, naloxone, an opioid receptor antagonist, improves tolerance to hemorrhagic shock. The purpose of this study was to determine whether naloxone would augment tolerance to hypotensive hypovolemic stress (lower body negative pressure [LBNP]) in healthy human males.Design:This study was a repeated measures design.Setting:The experiments were conducted in a laboratory setting.Subjects:Eight healthy male subjects were tested. The subjects' ages were 30 ± 4.0 yrs, height = 177 ± 7.0 cm, and weight = 75.5 ± 3.5 kg (mean ± SEM).Interventions:Subjects underwent two LBNP exposures terminated by the onset of vasodepression. At each of the exposures, using a double-blind procedure, the subjects received an intravenous injection of either saline placebo or naloxone in a dosage totaling 0.4 mg/kg.Measurements:Tolerance to the hypovolemic stress, heart rate, blood pressures, forearm blood flow, forearm vascular resistance were measured.Main Results:Naloxone reduced the tolerance to LBNP by 17%. Heart rate and blood pressure responses immediately before vasodepression were also attenuated by naloxone as compared with placebo. Forearm blood flow and vascular resistance were not altered by naloxone.Conclusion:Our results indicate that unlike animal models of hemorrhagic shock, blocking the opioid receptors in males reduced tolerance to a hypotensive hypovolemic stress.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To study microbial and susceptibility patterns and antimicrobial treatment responses in patients with severe, acute exacerbations of chronic obstructive pulmonary disease requiring mechanical ventilation.Design:Microbial investigation using tracheobronchial aspirates, bronchoscopy with a protected specimen brush, and bronchoalveolar lavage, as well as paired serologies. Evaluation of antimicrobial treatment by results of the initial investigation, susceptibility testing, and a repeated microbial investigation (tracheobronchial aspirates, bronchoscopy with a protected specimen brush, and bronchoalveolar lavage) after 72 hrs.Setting:A respiratory intensive care unit of a 1,000-bed teaching hospital.Patients:Fifty severely exacerbated and mechanically ventilated patients with chronic obstructive pulmonary disease.Interventions:Initial empirical antimicrobial treatment according to clinical judgment.Measurements and Main Results:Overall, 36 of 50 patients (72%) had evidence of a microbial origin. Community-acquired endogenous pathogens were present in 70% of patients, and Gram-negative enteric bacilli andPseudomonas/Stenotrophomonasspecies were present in 30%. All five isolates ofStreptococcus pneumoniaewere resistant to penicillin (three intermediately and two highly), and three were resistant to multiple antibiotics.Pseudomonasspecies revealed multiresistance in four of nine isolates (44%), andStenotrophomonas maltophiliarevealed multiresistance in one of two isolates. Antimicrobial treatment was modified according to diagnostic results in 11 of 31 patients (36%) with potentially pathogenic microorganisms. In patients who underwent a repeat investigation after 72 hrs, 24% of the initially present and potentially pathogenic microorganisms persisted. Inappropriate initial antimicrobial therapy was associated significantly with bacterial persistence (p< .002).Conclusions:Considering the diversity of microbial pathogens and the resistance rates especially toS. pneumoniaein this patient population, antimicrobial treatment should be based on the constant study of local microbial and susceptibility patterns along with routine microbial investigation of the individual patient.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To evaluate the accuracy and precision of an advanced thoracic bioimpedance cardiac output monitor by comparing it with conventional thermodilution.Design:Prospective data collected from 47 patients undergoing routine cardiac catheterization. The new bioimpedance system differs from its predecessors in electrode system configuration, advanced signal processing, use of a modified Kubicek equation, and a reliable estimate of left ventricular ejection time from the time derivative bioimpedance signals.Setting:A cardiac catheterization laboratory in a university affiliated teaching hospital.Patients:A series of 47 relatively homogenous patients undergoing routine cardiac catheterization for suspected cardiac disease.Measurements and Main Results:The data from the first 20 patients was used to determine optimal values for coefficients in the bioimpedance cardiac output equations. The coefficients found were used when the system was tested in the subsequent 27 patients. For the last 27 patients, a total of 80 simultaneous pairs of cardiac output measurements were made by conventional thermodilution and by thoracic bioimpedance. The mean difference between the two methods was −0.31 L/min and the standard deviation of the differences was (0.76 L/min). The correlation coefficient was r2= .72 (p< .001).Conclusions:The correlation between conventional thermodilution and thoracic bioimpedance cardiac output estimates was good and the standard deviation of the differences was lower than that reported for commercially available devices. The system can be used in the cardiac catheterization lab for reliable and continuous noninvasive measurement of cardiac output.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To compare pulse oximetry saturation (SpO2) with arterial blood gas saturation (SaO2) obtained during clinical routine to determine the optimal lowest reliable value of SpO2in ventilator-dependent patients before setting up a nurse-directed protocol of FIO2titration.Design:Prospective clinical study.Setting:Surgical intensive care unit in a university hospital.Patients:Thirty-three patients with a pulse oximeter probe in whom arterial blood gas was measured with a radial artery line.Interventions:SpO2was recorded by the nurses and compared with SaO2obtained by blood gas analysis with a co-oximeter. Two sensors currently used in our surgical intensive care unit and connected to a monitor (HP OmniCare M1165/66A; Hewett Packard, Andover, MA) were tested. In group I, the Durensor DS 100A (Nellcor Puritan Bennett, Pleasanton, CA), a reusable sensor, was used. In group II, the Oxisensor D25L (Nellcor Puritan Bennett), a nonreusable sensor, was used.Measurements and Main Results:In group I, 64 data pairs were obtained. In this group, SaO2ranged from 87 to 98% and SpO2ranged from 92 to 100%. The bias was −1.90% and the limits of agreement ranged from −5.56 to 1.76%. In group II, 47 data pairs were obtained. In this group, SaO2ranged from 87 to 99% and SpO2ranged from 92 to 100%. The bias was −2.49% and the limits of agreement ranged from −6.62 to 1.64%.Conclusions:In the range of SaO2tested, regardless of the sensor used, SpO2overestimated SaO2. Large limits of agreement were found. Based on this result, the authors concluded that before defining a nurse-directed protocol of FIO2titration with SpO2, the material used daily must be evaluated. A minimum threshold SpO2value of 96% in both groups I and II is more reliable to ensure SaO2≥ 90%.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To determine physician and nurse adherence with sedative, analgesic, and neuromuscular blocking agent guidelines in the management of mechanically ventilated patients in a medical intensive care unit.Design:Prospective cohort study.Subjects:One hundred consecutively admitted patients to a medical intensive care unit who required mechanical ventilatory support. A sample of 29 nurses, residents, and attending physicians were interviewed regarding their attitudes and perceptions of the guidelines.Measurement:Data were collected from concurrent medical records and included the following: demographic characteristics; clinical variables; physician prescriptions of sedative, analgesic, and/or neuromuscular blocking agents; nurse administration of these medications; documentation of monitoring; and assessment of patient hemodynamic status and behaviors. A semistructured interview was elicited from both nurses and physicians about their rationale for the use or nonuse of the guidelines.Results:Patients ranged in age from 24 to 87 yrs, mean 60.7 (±15.3) yrs. Admission Acute Physiology and Chronic Health Evaluation III scores ranged from 36 to 192, mean 93.8 (±30.5) and median 88. Length of mechanical ventilatory support ranged from 1 to 112 days, mean 14.8 (±20.0) days, and median 8 days; medical intensive care unit length of stay ranged from 1 to 46 days, with a mean of 9.8 (±8.1) days and a median of 8 days. Of the 100 patients, 47% died, 28% returned home, and 25% were discharged to a nursing facility. Eighty-five patients were administered one or more sedative, analgesic, and/or neuromuscular blocking agent, range 1-9 drugs, mean 2.5 (±1.5) drugs. Physicians prescribed 14 different medications; the most commonly administered drug was lorazepam (n = 71), followed by morphine (n = 39). Physicians and nurses had partial or total adherence to the guidelines in 58% of patients. The initial choice of the drug followed the guidelines in 60% of patients; the overall guideline was followed in 23% of patients. The most common rationales for nonadherence to the guidelines stated by both physicians and nurses were patient-specific factors, resident guideline learning curve, and physician medication preferences.Conclusion:Most patients required treatment for agitated behaviors. The majority of treatment regimens partially or totally adhered to the guidelines. Factors such as patient-specific disease states, resident guideline learning curve, and physician preferences of medications may have decreased adherence. Improving adherence to the guidelines is essential to assess their effectiveness in improving clinical outcomes.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:The aim of this study was to determine whether changing heat and moisture exchangers (HMEs) every 96 hrs rather than 24 hrs would affect their efficacy to preserve the heat and moisture of inspiratory gases. The impact of a prolonged use of the HME on its microbial colonization was also assessed.Design:Prospective cohort observational study.Setting:Intensive care unit of a university hospital.Patients:Thirteen consecutive patients with no previous history of respiratory disease requiring controlled mechanical ventilation with an HME for >4 days were evaluated.Interventions:The same HME was used for 96 hrs in each patient.Measurements and Main Results:In each patient, during the inspiration phase, the following measurements were performed: peak and mean airway pressures, mean values of temperature, and relative and absolute humidity of inspired gases. In each patient, measurements were performed after 1 hr of HME use and then daily up to the fourth day. On days 1 and 4, microbiological samples were obtained from the patients' bronchial secretions and the ventilator side of the HME. After 96 hrs of ventilation with the same HME, tracheal tube occlusion was never observed. Using the same HME for 96 hrs rather than 24 hrs did not affect its technical performances: temperature at 24 hrs: 32.2 ± 1.5°C (90.0 ± 34.7°F), at 96 hrs: 32.1 ± 1.6°C (89.8 ± 34.9°F); relative humidity at 24 hrs: 97.9 ± 2%, at 96 hrs: 98.1 ± 1.7%; absolute humidity at 24 hrs: 33.1 ± 2.4 mg H2O/L, at 96 hrs: 33.0 ± 2.5 mg H2O/L. This analysis was based on a total of 312 measurements performed on the 13 patients. Peak and mean airway pressures did not change during the 96-hr study period, with identical tidal and minute volumes in the study patients. On day 1, ten patients had a positive culture of their tracheal secretions at a colony count of ≥103colony forming units/mL. After 96 hrs of use with the same HME, only seven patients had a positive culture of their tracheal secretions. Cultures from the ventilator sides of the HMEs were all sterile (13/13) after 96 hrs of use.Conclusions:In patients free from previous chronic respiratory disorder and ventilated for neurologic reasons, changing the HME after 96 hrs rather than 24 hrs did not affect its technical performance in terms of heat and water preservation of ventilatory gases. There is also some indirect evidence of very little, if any, changes in the HME resistance. No bacterial colonization of the ventilator sides of the HMEs was observed after 96 hrs of use. However, other large clinical trials should be undertaken to confirm the safety of extending the time between HME changes.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Objective:To compare the prognostic ability of sensory evoked potentials in cardiac arrest survivors with the outcome predicted by a panel of experienced emergency physicians based on detailed prehospital, clinical, and laboratory data.Design:Inception cohort study.Setting:Medical intensive care unit and department of emergency medicine at a university hospital.Patients:A total of 162 unconscious, mechanically ventilated patients who survived ≥24 hrs after resuscitation from cardiac arrest.Interventions:Recording of sensory evoked potentials and outcome prediction after review of detailed clinical and laboratory data by emergency physicians within 24 hrs after cardiac arrest.Measurements and Main Results:At 6 months, the outcome of 36 patients was classified as favorable and 126 patients were rated as poor. After review of prehospital data, emergency physicians predicted favorable vs. poor outcome with a sensitivity of 70% and a specificity of 65%. After additional assessment of data 1 hr after cardiac arrest, the sensitivity of emergency physician predictions increased to 80%, whereas the specificity decreased to 48%. Outcome prediction by emergency physicians was most accurate after obtaining detailed patient data 24 hrs after cardiac arrest (sensitivity, 81%; specificity, 58%). In 35 of 36 patients with favorable outcomes, the cortical evoked potential N70 peak was detected between 72 and 128 msec. Of 113 patients with an N70 peak latency > 130 msec or an absent N70 peak, all except one had a poor outcome. By using a cutoff of 130 msec, the N70 peak latency alone had a sensitivity of 94% and a specificity of 97%. The predictive accuracy of the N70 peak latency was significantly higher than the clinical assessment 24 hrs after cardiac arrest (91% vs. 76%,p= .0003).Conclusion:In unconscious cardiac arrest survivors, a recording of long-latency sensory evoked potentials is more accurate in predicting individual outcome than an emergency physician review of clinical data.

ISSN:0090-3493    

出版商:OVID    

年代:2000

数据来源: OVID