摘要:

An analysis of 23 CT scans performed on 20 patients was carried out in an approximate 2-yr period. In 15 patients, CT scans were judged useful by subsequent clinical course when they indicated maintenance or alteration of existing treatment strategies. CT scans in five patients were not helpful. When judged by eventual outcome, the impact of CT scans remains uncertain. The influence of transportation is difficult to assess; it requires experienced team work and is contraindicated in cases where respiratory or circulatory stability might be seriously impaired.

ISSN:0090-3493    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Little is known about dopamine pharmacokinetics in pediatric patients, especially in critically ill infants and children who often receive treatment with dopamine. Arterial plasma concentrations of dopamine were measured in 27 patients who were hemodynamically stable and received dopamine for at least one hour. The dopamine levels were measured using liquid chromatography with electrochemical detection. Dopamine clearance averaged 96.2 ± 55.4 ml/kg min in 13 patients in the neonatal ICU, and 58.8 ± 51 ml/kg min in 14 patients in the pediatric ICU. Six patients had renal (BUN >25 mg/dl, or creatinine >1.2 mg/dl) or hepatic (liver enzymes >3 times normal) dysfunction. Dopamine clearance in these patients (25.1 ± 17.2 ml/kg min) was substantially lower than in the other patients (p< .01). Neither postnatal nor gestational age correlated with dopamine clearance. Substantial interindividual variation was observed in steady-state dopamine clearance in critically ill infants and children, and plasma dopamine could not be predicted accurately from the dopamine infusion rate. Because of the more than threefold prolongation of dopamine clearances in patients with hepatic or renal dysfunction, these patients may be more likely to suffer toxic effects of dopamine at the usual drug infusion rates.

ISSN:0090-3493    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The incidence and risk factors of positive catheter tip cultures were studied prospectively in 392 consecutive children undergoing cardiac surgery under cover of cephalothin prophylaxis. A total of 1649 catheter tips were cultured and 58 (3.5%) yielded positive cultures. Specifically, the incidence of positive catheter tip cultures for iv, central venous, arterial and pulmonary arterial (PA) catheters was 0.9%, 5.9%, 3.9% and 10.6%, respectively, whereas one of the six surgically placed venous and arterial catheters had a positive tip culture and none of the 279 transthoracic catheters.Staphylococcus epidermidiswas isolated from 79% of the positive tip cultures. Ten percent of the children had one or more positive tip cultures but none developed catheter-related septicemia or endocarditis. Stepwise logistic regression analysis revealed that longer in situ time (p< .001), younger age (p< .001), and inotropic support (p= .003) were significant independent predictors of risk for children developing positive catheter tip cultures. The safe in situ period for arterial, central venous, and PA catheters is 3 days in infants under 1 yr and 4 and 6 days for arterial and central venous catheters, respectively, in older children, if 0.95 cumulative probability of remaining free of a positive tip culture is accepted. The data generally support the bacteriologic safety of invasive hemodynamic monitoring in infants and children undergoing cardiac surgery.

ISSN:0090-3493    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Stress ulcer is a dangerous complication for the critically ill patient. Prophylaxis with antacids can undoubtedly reduce this risk, if gastric pH is maintained above 3.5. Histamine receptor antagonists may achieve this more conveniently. We have studied the effects of ranitidine, given either as 50-mg boluses every 6 h or as one of two infusion regimes (125 or 250 μg/kg- h), in controlling pH in critically ill patients on a ventilator. The percentage of samples with a pH less than 4 fell in all groups during therapy; while there was no significant difference between groups, pH control was achieved more rapidly in the bolus group. Infusion therapy with ranitidine is an attractive concept but a loading dose must be used. The presence of occult blood in the gastric juice did not correlate with pH and was not affected by ranitidine therapy.

ISSN:0090-3493    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

In a prospective 30-month study of nosocomial infections in a pediatric ICU (PICU), the incidence, sites, and causes of infection were determined. Factors associated with increased risk of infection were investigated. In 1,388 patients who remained in the PICU for a minimum of 72 h, 116 infections occurred (6.1 infections/100 admissions). Primary bacteremias comprised 38% of PICU infections and lower respiratory infections comprised 15%. The remaining infections were divided equally among GI, skin, eye, upper respiratory, postoperative wounds, and other sites. Coagulase-negative staphylococci,Pseudomonas aeruginosa, andStaphylococcus aureuswere the most prevalent pathogens.Surgical patients had similar rates of infection to medical patients. Patients in the first 2 yr of life, particularly those between 7 and 30 days of age, had the highest rate of infection. Onset of infection was more common after the first week in the PICU with 11% of patients staying 14 to 20 days, 27% of patients staying 21 to 27 days, 48% of patients staying 28 to 34 days, and 52% of patients staying more than 35 days before the onset of infection. The risk of nosocomial infection increases with arterial and central line use, prolonged intubation, ventilation, intracranial pressure monitoring, and paralysis.

ISSN:0090-3493    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

High-dose fentanyl anesthesia is widely used in cardiac surgery. Its immediate side-effects are well known. However, its late adverse effect manifested by extreme truncal rigidity, decreased chest wall compliance, hypoventilation, respiratory acidosis and hemodynamic instability is not sufficiently appreciated. Of 380 patients who underwent aortocoronary artery bypass under high-dose (100 μg/kg) fentanyl anesthesia, 29 (7.6%) developed the sudden onset of extreme thoracic and abdominal rigidity, leading to respiratory depression 2 to 6 h postoperative, after an apparently normal recovery from the anesthesia. In 15 patients, a high plasma level of fentanyl (5.2 to 7.8 ng/ml) correlated with the clinical events. Administration of naloxone or a muscle relaxant rapidly reversed this late complication of fentanyl, thought to be due to re-entry of fentanyl into plasma from deposits in adipose tissue, muscle and the GI tract, leading to a secondary peak in plasma fentanyl. It is more likely to be encountered when hypothermia, rewarming, and acidosis occur in the postoperative period. Awareness of this life-threatening complication is critical in patients undergoing surgery with fentanyl anesthesia.

ISSN:0090-3493    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The optimal rate of chest compression during CPR in man has been debated. Recently, the end-tidal carbon dioxide concentration (Petco2) has been shown to correlate with cardiac output during CPR in experimental animals. Eighteen prehospital cardiac arrest patients were studied to determine the effect of external chest compression rate on the Petco2and BP in man when ventilation rate, ventilation inspiration time, applied compression force, and a 50:50 downstroke:upstroke ratio were held constant using a microprocessor-controlled CPR Thumper“. Compression rate was increased from 60 to 140/min in 20 beat/min increments.The Petco2was 1.7 ± 0.2% at a compression rate of 60/min and did not change significantly at increased rates. Systolic BP fell progressively from 59 ± 5 mm Hg at 60/min to 46 ± 4 mm Hg at 140/min. Diastolic BP remained approximately 23 mm Hg at all rates studied.Using a CPR manikin, we found that greater Thumper compression force was necessary to sustain the same sternal displacement and to achieve the same applied sternal pressure when the rate was increased due to a rate-limited fall in the compression duration.

ISSN:0090-3493    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Calcium channel blockers (CCBs) may produce profound myocardial depression. Glucagon antagonized verapamil-induced hypotension and bradycardia in rats; however, glucagon's ability to antagonize other CCBs is unexplored. This study determined: a) if glucagon reverses verapamil-induced depression by a direct cardiac effect, b) if myocardial depression induced by diltiazem and nifedipine (representing different classes of CCBs) is also reversed by glucagon, and c) the glucagon concentration needed to reverse myocardial depression. Isolated rat hearts were perfused at a constant flow rate in a Langendorff preparation. Developed pressure (dP), contractility (+dP/dtmax), relaxation (-dP/dtmax), heart rate, and coronary vascular resistance were recorded. A CCB (n = 6, each blocker) was infused until >50% depression of contractility was achieved. Glucagon was then simultaneously infused (perfusion concentration of 0.6–1.1 × 10−7M), and repeat cardiac variables were recorded. In a separate group of 36 hearts, glucagon dose response was determined. After producing a >50% depression in dP/dtmaxwith 3 μmol of diltiazem, a single concentration of glucagon was infused simultaneously into each heart (perfusion concentrations between 10−6and 10−9M) and percent recovery of baseline function was determined. Glucagon restored baseline contractility and dP with all three CCBs. Complete reversal of diltiazem-induced myocardial depression occurs at glucagon concentrations ≥5 × 10−7M. We conclude that a) glucagon directly reverses myocardial depression from three classes of CCBs at concentrations achieved in vivo, and b) glucagon may be useful in the treatment of CCB-induced myocardial toxicity.

ISSN:0090-3493    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

We have previously designed a computerized system to automatically deliver PEEP to maintain functional residual capacity (FRC) at a desired value. The purpose of this study was to compare the computerized PEEP titration system with a standard clinical PEEP titration algorithm in the animal adult respiratory distress syndrome (ARDS) model.Thirty mongrel dogs were anesthetized, paralyzed, intubated, and ventilated. An acute pulmonary injury was produced using 0.09 ml/kg of oleic acid. The animals were then given PEEP for 5 h. Arterial and venous blood gases, BP, thermodilution cardiac output, heart rate, body temperature, total respiratory system compliance (Cir), and end-tidal CO2were measured every 30 min. FRC was measured using an automated sulfur hexafluoride washout system every 15 min. The animals were allocated randomly to three ten-animal groups. The first group had PEEP titrated using a standard clinical protocol; the remaining two groups had PEEP updated at 15-min intervals under computer control to maintain FRC at 1.4 times the postanesthetized, post-paralyzed, preinjury value. The second group received fixed 3-cm H2O PEEP steps. The third group had variable size PEEP steps depending on the output of a proportional, integral, and derivative (pID) controller. Paco2 was maintained at 35.8 ± 3.4 (sd) torr. There was a significant difference in PEEP delivered between the three groups (p= .0006) and in FRC (p= .005). There was no significant difference in PaO2(p= .80) or venous admixture (&OV0422;va/&OV0422;t) (p= .84) between the three groups. There was also no significant difference in hemodynamics, alveolar-arterial Po2difference, oxygen delivery, arterial or mixed venous oxygen saturation, Ctr, or the end-tidal minus Paco2difference. There was a significant difference in how fast the groups reached their desired goal (p= .0001). The manual PEEP titration groups took 90 ± 20 min (sem) to reach a &OV0422;va/&OV0422;t of 18% or less compared with 50 ± 5 and 23 ± 2 min for the fixed step and PID control, respectively, to reach 90% of the desired FRC. The manual control group required 8 ± 5 (SD) more blood gases to reach optimal PEEP levels than the computer-control group.This study demonstrates in an animal model of ARDS that computer control of PEEP titration based on FRC was not significantly different from a standard clinical PEEP titration algorithm. PEEP titration based on FRC measurements can reach optimal levels sooner and continue to adapt more quickly to the patient's changing pathology.

ISSN:0090-3493    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

A model of closed head injury in rats was developed using a calibrated weight-drop device. The development of edema was studied in various brain regions (cerebral hemispheres, brain stem, cerebellum) using a linear specific gravity gradient column. Regional brain tissue density was measured within 1 min, at 15 and 60 min, 18 h, 4 and 10 days after injury to the left cerebral hemisphere, and was compared with values in sham-operated and control rats. Significant edema (i.e., reduced specific gravity) occurred only in the traumatized hemisphere and was maximal at 18 h. A neurologic severity score (NSS) was developed to evaluate the status of the rat after injury. Specific gravity was significantly correlated with NSS at 18 h after injury.The affected hemisphere displayed hemorrhagic lesions as early as one hour post head trauma (HT), which evolved into hemorrhagic necrosis at 18 h. A pathologic score, evaluated 18 h post HT based on size and severity of the lesion, was correlated with the NSS and evaluated for each rat at one hour and 18 h postimpact. This correlation was found to be highly significant. This model of brain injury may be useful in future studies on the effects of therapeutic agents.

ISSN:0090-3493    

出版商:OVID    

年代:1988

数据来源: OVID