We obtained hourly measurements of Ptco2 from two gastric tonometers inserted orally in 19 healthy volunteers. One tonometer measured Ptco2 by the intermittent saline method, whereas the other measured Ptco2 using a newer continuous air method. Subjects received intravenous 5% dextrose during the first 6 hours of the experiment followed by a continuous infusion of a solution of ranitidine in 5% dextrose for another 6 hours. The ranitidine infusion was titrated to maintain gastric fluid pH ≥ 4.
Comparison of air to saline tonometry yielded a bias of −1.3 mm Hg with a limit of agreement of 6.6 mm Hg under optimal conditions of optimal gastric fluid pH (gastric fluid pH ≥ 5.0). Measures of Ptco2 were lower with ranitidine for either group, 45.3 ± 1.3 mm Hg versus 39.7 ± 0.5 mm Hg for saline (P < .01) and 45.9 ± 1.0 versus 41.3 ± 0.5 for air (P < .01). The mean Pco2 gap (Ptco2 - Parterialco2) at gastric fluid pH ≥ 5.0 was 1.4 mm Hg, with a standard deviation of 2.7 mm Hg. A span of three standard deviations yields a normal limit for Pco2 gap of 9.5 mm Hg.
Measures of Ptco2 with the air tonometer method are similar to those obtained with saline tonometry. The reliability of Ptco2 measurements with either method improved with the use of ranitidine to maintain gastric fluid pH ≥5. 相似文献
: Dogs were randomized to receive either 10 mg/kg U-74389G (n = 10), or a saline control (n = 11). After baseline measurements of hemodynamics and gas exchange, they were then randomized to receive either 0.2 mg/kg endotoxin or a saline infusion. Measurements of hemodynamics and gas exchange were repeated. The study was concluded 70 minutes after endotoxin infusion and the lungs were then removed for histologic evaluation.
: In endotoxin-treated control animals, P02 decreased (278 ± 123 mm Hg to 67 ± 13 mm Hg, P < .05) and intrapulmonary shunt increased (12.9% ± 1.1% to 28.2% ± 11.4%, P < .05) after endotoxin. Pretreatment with U-74389G attenuated the decrease in PO2 (476 ± 61 mm Hg to 226 ± 143) and the increase in intrapulmonary shunt (12.6% ± 6.1% to 14.3% ± 6.8%) observed after endotoxin. The extent of lung injury and systemic hemodynamics were similar between control or U-74389G-treated dogs.
: A free-radical-scavenger can attenuate the gas exchange defect commonly associated with endotoxin but it does not improve the derangement of systemic hemodynamics. 相似文献
In 11 patients with septic shock of recent onset, blood was sampled for determinations of TNF, IL-1, IL-6, and IL-10. The degree of organ failure was scored for four organ systems (respiratory, hepatic, renal, hematologic) in the first 48 hours of the study.
The APACHE II score was 21 ± 4. Three patients died. IL-10 levels were directly correlated with TNF levels (r = 0.73, P < .05) and IL-6 levels (r = 0.67, P < .05); and inversely correlated with total C3 (r = −0.73, P < .05) and CH50 (r = −0.68, P < .05). Both IL-10 and TNF levels were correlated to the organ failure score (r = 0.75 and r = 0.68, both P < .01). Six patients with high IL-10 levels (>60 pg/mL) had lower C3 (37 ± 11 v 62 ± 10 mg/dL) and CH50 (32 ± 7 v 68 ± 19%), and higher organ failure scores (5.7 ± 0.8 v 3.8 ± 1.3) than those with low IL-10 levels (all P < .05).
Although IL-10 has an inhibitory effect on the production of cytokines, it is released together with TNF and IL-6 in patients with septic shock. IL-10 blood levels are directly related to the severity of inflammation and the development of organ failure in septic shock. 相似文献
A prospective observational study was conducted at a Comprehensive Cancer Center, University Hospital. Fourteen consecutive critically ill, mechanically ventilated patients on PSV with positive end-expiratory pressure were studied. Flow triggering was added to PSV in spontaneously breathing ventilated patients.
Respiratory rate (f), minute ventilation (V), patient work of breathing (WOBp), respiratory drive (P0.1), rapid shallow breathing index (f/Vt), tidal volume (Vt) and a visual analog scale of breathing effort and comfort all improved. There was a large decrease in WOBp, and P0.1, when flow triggering was added to PSV (P < .001). There was a moderate decrease in f/Vt during the same procedure (P < .01). Twelve patients felt subjectively better with the intervention.
Flow triggering offers an excellent complement to PSV because it improves patient comfort and reduces the magnitude of the inspiratory effort as well as the delay time between inspiratory muscle contraction and gas flow. It augments gas exchange at no metabolic cost to the patient while reducing the work of breathing. 相似文献
: Blood samples of 29 patients were taken 24 hours after the diagnosis of sepsis. HSP70 expression and TNF- level were measured using indirect immunofluorescent analysis and a commercially available enzyme-linked immunosorbent assay method, respectively.
: PBMCs expressed significantly high levels of HSP70 (11.9 ± 5.6 [sd]) compared with those of the healthy control group (3.2 ± 2.1 % positive cells). Such enhanced levels were correlated to plasma TNF- concentrations (r = .99, P < .01). This study failed to demonstrate a relationship between HSP70 production and clinical outcome.
: These findings give further evidence that also in humans, heat shock response is activated during sepsis. The correlation observed between HSP70 overproduction and TNF- plasma concentrations suggests that HSP70 exerts a possible protective effect against TNF- cytotoxicity. Such hypothesis has not been confirmed by our clinical data. 相似文献
This was a prospective, controlled, experimental study conducted in an animal research laboratory on 15 male mongrel dogs. Escherichia coli endotoxin (1 mg/kg) was injected intravenously.
Hepatic, renal, and iliac blood flow and cardiac output (CO) were measured before and 15, 30, 45, 90 and 180 minutes after injection of Escherichia coli endotoxin (1 mg/kg) (n = 6). NOx efflux from the organs was calculated by measuring plasma NOx levels. The arterial blood levels of NO-Hb were also measured (n = 4). As control studies, blood samples from dogs (n = 5) without exposure to endotoxin were assayed at 180 minutes for NOx and NO-Hb. Following endotoxin injection, mean arterial pressure decreased and reached its lowest value at 90 minutes (baseline vs. 90 minutes: 119.1 ± 5.8 vs. 82.5 ± 16.7 mm Hg, P < .0001). Hepatic artery bloodflow increased significantly (baseline vs. 180 minutes: 23.6 ± 12.0 vs. 170.0 ± 68.4 mL/min, P < .0001). There were no significant changes in plasma levels of NOx, uptake or release of NOx across the measured vascular beds, NO-Hb levels at anytime point. In the portal system, the portal vein flow correlated with NOx release (R = 0.69, P < .0001).
In the early phase of endotoxemia in the dog, the significant reduction in systemic vascular resistance and hepatic arterial resistance are not associated with any measurable NOx release in the systemic circulation or the liver. 相似文献
We compared the response to exogenous increases in blood [K+] in rabbits given an infusion of potassium chloride (KCl) intravenously (IV) (0.2 mol/L; KCl group; N = 7) to a group given 0.9% sodium chloride (NaCl) (control; N = 7). The rabbits underwent low-frequency, isometric twitch stimulation of the left hindlimb (square wave pulses 100 microseconds, 40V, 0.25 Hz) throughout the experiment. Both groups received 0.9% NaCl (25 mL/h) during the first hour of twitch stimulation and experienced similar decreases in hindlimb forces to 70% of initial force. A continuous infusion of KCl or of saline (60 mL/h) was started, and hindlimb stimulation continued for 2 hours.
There were no changes in [K+] in the control group, and twitch forces progressively declined during the next 2 hours (369 ± 47 g to 279 ± 34 g, P < .01). Arterial [K+] increased in the KCI group from 2.6 ± 0.1 to 10.1 ± 0.5 mmol/L (P <.01), and hindlimb twitch forces almost doubled (418 ± 49 g to 756 ± 55 g, P < .01). Force frequency curves showed improved contractility in the KCI group at stimulation frequencies below 30 Hz.
Exogenous increases in blood [K+] potentiate skeletal muscle contraction in intact animals and reverse low-frequency twitch fatigue. A possible mechanism may be the maintenance of intracellular [K+] by hindering K+ efflux from skeletal muscle cells. 相似文献
Ten anesthetized piglets were studied during conditions of normovolemia, hypovolemia, and hypervolemia. The effects of an infusion of dobutamine were examined under normovolemia and hypovolemia. Cardiac output was measured by thermodilution, and ITBV was measured by double-indicator dilution.
CI was correlated to CVP with r2 = .42 (P ≤ .01), to PAOP with r2 = .43 (P ≤ 5.01), to RVEDV index with r2 = .21 (P ≤ .01), and to ITBV with r2 = .78 (P ≤ .01) (pooled absolute values). Bias (mean difference of the percent changes with NORMOVOLEMIA = 100%) ± 1 SD; for SVI - ITBV index was 1 ± 22%, for SVI — CVP it was −128 ± 214%; for SVI — PAOP it was −36 ± 46%; and for SVI -RVEDV index it was 1 ± 29%. Dobutamine infusion increased heart rate (to about 190 × min−1) and CI by 30% in normovolemia and hypovolemia, while ITBV remained basically unchanged.
Under the experimental conditions choosen neither CVP, PAOP, nor RVEDV reliably indicated changes in circulating blood volume, nor were they linearly and tightly correlated to the resulting changes in SVI. ITBV reflected both changes in volume status and the resulting alteration in cardiac output. The possibility that ITBV might be cardiac output-dependent was not supported. ITBV, therefore, shows potential as a clinically useful indicator of overall cardiac preload. 相似文献
Methods. Mechanical bone quality of a femoral head slice was assessed by destructive compression testing combined with bone mineral density measurements using peripheral quantitative computed tomography. Fourteen patients with walking pains were attainable for a radiographical follow-up mean 7.1 years after implantation.
Results. Radiolucent lines along the stem were evident in 11 of 14 femurs, most of them seen in Gruen zones 7, 6, 1, 3, 14, and showed strong correlations to preoperative bone strength (r=−0.80; P<0.001) and axial stiffness (r=−0.75; P=0.002), yet not to bone mineral density (r=−0.67; P=0.009). Slight varus deviations <3° were noted in six femurs. Preoperative strength was reduced in this femurs to 54% (P=0.006), and stiffness to 61% (P=0.038), while bone mineral density did not differ significantly.
Conclusions. Femoral prosthesis loosening after seven years can be predicted by mechanical bone quality of the femoral head at the time of implantation. Bone mineral density measurements may also indicate future stem loosening but have to interpreted carefully, keeping in mind a poorer predictive value.
Relevance Indications and choice of type of hip arthroplasty should be balanced in osteoporotic bones in particular. While preoperative bone mineral density measurement allows the prediction of mechanical bone quality, its relevance in predicting failure in arthroplasty treatment remains unclear. 相似文献
We used the in situ autoperfused feline ileal preparation to simultaneously examine microvascular permeability, reflected as the ileal lymph to plasma protein concentration ratio (CL/C P), and ileal Vo2-Do2 relationships after either intravenous LPS (2.0 mg/kg; N = 5) or I/R injury (n = 5), and in matching controls (n = 5).
As expected, all LPS-treated and I/R-injured animals were found to have extensive ileal histological damage and marked increases in the CL/CP compared with controls (0.315 ± 0.009 and 0.329 ± 0.034, respectively, v 0.097 ± 0.009; P < .001, both comparisons). In addition, the critical Do2 (Do2c) was elevated, and the critical oxygen extraction was decreased in both the I/R and LPS groups relative to controls. However, as initially hypothesized, the Vo2 at the critical Do2 was markedly decreased in the I/R group compared with that of the LPS group.
These data indicate that I/R injury is insufficient to account for the systemic organ Vo2-Do2 alterations that occur with LPS injury. 相似文献
Ulbar|Materials and Methods: All dogs received a standard anesthetic, and then one group (n = 6) received 2 hours of cardiopulmonary bypass followed by 4 hours of observation. A second group (n = 6) received a monoclonal antibody (6 mg/kg) to CD18, a neutrophil adherence factor, immediately before cardiopulmonary bypass. A third group (n = 6) did not receive cardiopulmonary bypass or antibody.
Using flow cytometry we found that the antibody bound essentially all neutrophil CD18 sites. All three groups had similar gas exchange and hemodynamics. Lung and heart histology results were similar between groups. By echocardiography, five animals receiving cardiopulmonary bypass alone showed regional wall abnormalities, whereas only one receiving antibody showed wall motion abnormality (P < .05). Following cardiopulmonary bypass, intracellular myocardial pH was higher (P < .05) in the antibody-treated group compared with the group that had cardiopulmonary bypass alone (7.23 ± 0.05 v 7.07 ± 0.07 respectively).
Monoclonal antibodies to CD18 can prevent the deterioration in cardiac function routinely observed following cardiopulmonary bypass. 相似文献
: Ten pentobarbital-anesthetized, mechanically ventilated dogs were randomly assigned to receive either N-AC (150 mg/ kg loading dose in 1 hour, followed by 20 mg/kg · h maintenance dose) or D5W. After the loading dose, each dog received 3 mg/kg Escherichia coli endotoxin intravenously. After 30 minutes, saline infusion was started to restore and maintain baseline filling pressures.
: The loading dose of N-AC increased Do2 significantly (from 661 ± 54 to 914 ± 190 mL/min, P < .05), but Vo2 remained stable. After the administration of endotoxin, fluid challenge restored cardiac output to baseline, in both groups. Hemoglobin and, thus, Do2 were slightly lower in the N-AC-treated dogs, but Vo2 was similar in both groups. At the end of the study, O2ER was significantly higher in the N-AC-treated dogs than in the control dogs. Blood lactate levels fell more rapidly in the N-AC dogs than in the control dogs. Blood lactate levels returned to normal in the N-AC dogs but not in the control dogs. Tumor necrosis factor (TNF) also decreased significantly in the N-AC dogs but remained elevated in the control dogs.
: These data indicate that N-AC administration in endotoxic shock is well tolerated, may increase oxygen availability to the tissues, and is associated with an attenuation of TNF release. 相似文献
Pigs were anesthetized and mechanically ventilated. We measured CO by thermodilution, mean circulatory filling pressure (MCFP) by inflating a balloon in the right atrium, blood volume by dye dilution, and Cv by rapid blood infusions. RVR was calculated from MCFP - Pra/CO). After baseline measurements, we infused 10 μg/(kg x h−1) of Escherichia coli endotoxin. Eight animals also received 30 mL × kg−1 of dextran over the 2 hours (volume treated), and seven did not (no volume). After 2 hours we injected 25 mg × kg−1 of the NO synthase inhibitor, L-NAME, and repeated the measurements.
In volume-treated animals, CO increased from 3.9 ± 0.7 to 5.4 ± 0.8 L x min−1 (P < .05), and blood pressure (BP) fell from 118 ± 9 to 76 ± 12 mmHg. MCFP rose, and there was no change in RVR or Cv, whereas capacitance increased (ie, right shift of pressure-volume curve). Cardiac function (ie, Starling curve) did not change. In no-volume animals, CO fell from 4.47 ± 0.64 to 2.50 ± 0.86 L × min−1, BP from 114 ± 10 to 9 13 mmHg and MCFP fell. Systemic vascular resistance did not change. Cardiac function was markedly depressed, and the heart rate increased from 143 ± 13 to 203 ± 30 beats x min−1. L-NAME restored BP in both groups but also increased RVR and depressed cardiac function.
Changes in vascular tone during endotoxemia are dependent on volume status. The increased cardiac output in volume-treated septic animals occurred because of an increase in stressed volume due to the volume given in combination with a dilated vasculature. L-NAME restored arterial tone but decreased CO because of a rise in RVR and decrease in cardiac function. 相似文献
It was confirmed that the severity of atherosclerosis increases significantly with age (P < 0.001) and elastin content decreases with atherosclerosis (P < 0.001). The hydrolysis of the aortic elastins using pancreatic porcine elastase (PPE) was studied. It was observed that increased elastolytic activities are connected with severity of atherosclerosis (P < 0.001) and both Vm and Km apparent kinetic parameters are affected (P < 0.001). Correlation tests have shown that enzymatic hydrolysis is significantly modified by cholesterol (P < 0.05), calcium (P < 0.001) and magnesium concentrations (P < 0.01) but only cholesterol changes significantly Vm and Km parameters. 相似文献
The frequency of adult respiratory distress syndrome (ARDS) was significantly lower (P < 0.05) in the dextran group (0 of 12) than in the Ringer group (4 of 11). Thus, in the initial treatment of traumatic-haemorrhagic shock and in the post-resuscitative period dextran 70 would seem of advantage over Ringer's acetate both in shortening the shock period and in reducing the frequency of adult respiratory distress syndrome. 相似文献
: We tested all available variables using survival as the end point. A population of 223 patients (652 measurements) with compromised circulatory status was studied. We evaluated traditional variables: (1) morphological and physical data, (2) elementary right heart catheterization data, and (3) usually calculated variables, versus (4) new modeled variables. These new modeled variables were derived from a previously validated computer program for hemodynamic evaluation. They expressed differences between observed hemodynamic performance and estimated needs.
: Among traditional variables, major prognostic factors were: (1) in all patients, lactate level elevation, physical signs of hypoperfusion, and a decreased systemic arterial pressure; (2) in septic patients, a high Pao2/Sao2 ratio; (3) in nonseptic patients, low left ventricle work indices. In all cases, modeled hemodynamic variables assessing performance-needs adequacy enhanced the prognostic value of hemodynamic monitoring.
: Compared with traditional variables, modeled variables were found of greater interest to quantify pathophysiology of shock. These results enabled us to validate the initial step of the hemodynamic reasoning formalization and to develop “new” diagnostic criteria that more closely fit the interrelationship between pathophysiology, diagnosis, and prognosis. 相似文献