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Biomedical subjects

R Ritz

Publications and source records attributed to R Ritz.

At least 19 recordsLinked to original sources
PubMed2001

Intensive care unit admission in patients with haematological disease: incidence, outcome and prognostic factors.

OBJECTIVES: To examine incidence and outcome of intensive care unit (ICU) admission in patients with haematological malignancy and analyse prognostic factors associated with outcome. DESIGN: Retrospective cohort study in an intensive care unit of a tertiary referral center. PATIENTS: 78 patients with severe haematological malignancy were admitted 97 times between 1990-97 to the medical ICU for septic shock (18), respiratory failure (30), postoperative monitoring (19), cardiovascular (10) and central nervous complications (8) or for other reasons (12). Median age was 43 (4-73) years, average duration of ICU stay was 4 (1-43) days. Forty-two patients required mechanical ventilation, 46 vasopressors and 8 haemodialysis. RESULTS: Rates of ICU admission differed by treatment of the underlying disease. There were 18, 10 and 27 ICU admissions per 100 treatments in patients undergoing chemotherapy for acute leukaemia, autologous and allogeneic stem cell transplantation (p <0.005) respectively. Thirty-two of 78 patients died within 60 days of ICU admission. Organ failure, i.e. cardiovascular failure requiring vasopressors, respiratory failure requiring mechanical ventilation and renal failure, requiring haemodialysis, was most significantly associated with outcome. Mortality by day 60 after admission was 16%, 36%, 64%, and 83% (p <0.0002) for patients without organ failure, and for patients with 1, 2 or 3 failing organs. In a multivariate logistical regression model, only the organ failure score (p <0.0005) and evidence of liver damage, defined as ASAT or ALAT >100 IU/ L (p <0.007), but not age, sex, primary disease and treatment of the underlying disease predicted outcome. CONCLUSION: Multi-organ failure and evidence of liver damage but no other patient, disease, or treatment related factor predict outcome in patients with haematological disease admitted to the ICU.

Adult↗
PubMed2001

Chest pain early after percutaneous coronary intervention: incidence and relation to ECG changes, cardiac enzymes and follow-up events.

To investigate the incidence of chest pain early after percutaneous coronary interventions and its correlation with ECG changes, cardiac enzymes, clinical and procedural variables and follow-up events, we prospectively studied 199 patients (84% male; mean age, 60.1 +/- 9.4 years) after primary successful percutaneous coronary interventions (21% PTCA; 79% additional stent implantation). During the first 16 hours following the intervention, the occurrence of chest pain was noted, ECGs were recorded and serial measurements of cardiac enzymes were performed. Seventy-six patients (38%) with elevated enzyme levels at time 0 were excluded. A clinical follow-up was obtained at 6 months. Forty patients (32.5%) experienced chest pain; new ECG changes were detected in 3 (2.5%). The mean levels of all enzymes were significantly higher in patients with chest pain 16 hours after the intervention. In patients with chest pain versus those without, CK-MB mass and troponin I levels higher than twice the upper normal limit were seen in 43.6% versus 11.0% (p < 0.0001) and 45.0% versus 17.3% (p < 0.002), respectively. Elevated troponin I (< 0.004) and CK-MB mass (< 0.04) as well as presumed ischemic chest pain (< 0.03) could be identified as risk factors for recurrent chest pain during follow-up. In conclusion, chest pain was common early after percutaneous coronary interventions and correlated with elevated cardiac enzymes, suggesting peri-interventional myocardial necrosis. Elevated levels of CK-MB mass and troponin I, as well as presumed ischemic chest pain, were associated with recurrent chest pain during follow-up.

Aged↗
PubMed2000

Auditory and electroencephalographic effects of midazolam and alpha-hydroxy-midazolam in healthy subjects.

AIMS: Whereas cortical EEG effects of benzodiazepines are well characterized, information about benzodiazepine effects in other areas of the central nervous system is sparse. This study investigated the action of midazolam and its active metabolite alpha-hydroxy-midazolam on different parts of the auditory pathway in six healthy volunteers in a randomized, double-blind, three-way cross-over study. METHODS: Acoustically evoked short (SLP) and middle (MLP) latency potentials, transitory evoked otoacoustic emissions (TEOAE), and EEG power spectra were analysed after short i. v. injections of placebo, or 0.15 mg kg-1 midazolam, or alpha-hydroxy-midazolam, respectively. RESULTS: All subjects fell asleep during the 4 min infusion of active drug. SLP showed a significant transient increase of Jewett wave V 10 min after injection for midazolam and alpha-hydroxy-midazolam while the latency of wave I was unchanged. Both benzodiazepines induced a marked and long-lasting MLP amplitude decrease for 240 min with slow recovery over the following 360 min. No changes of TEOAE were observed. In agreement with earlier reports, increases in EEG beta activity and decreases in alpha activity were observed after administration of either drug. CONCLUSIONS: Systemically administered benzodiazepines modulate the auditory pathway above the level of the cochlea. While SLP changes were closely associated with sedation and high plasma benzodiazepine concentrations, MLP effects persisted for hours after sedation even at low benzodiazepine plasma levels. Evoked potentials may therefore be more sensitive than EEG as a tool to monitor benzodiazepine effects.

Adult↗
PubMed2000

Mental stress increases right heart afterload in severe pulmonary hypertension.

Little is known about mental stress effects on the pulmonary circulation in health and disease. The current study was conducted to investigate whether pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) would further increase during standardized mental stress testing in patients with severe pulmonary hypertension. The study was a prospective analysis of seven patients (average age: 40 years, range from 21 to 56 years) with severe pulmonary hypertension (primary: n = 4, secondary forms: n = 3; resting mean pulmonary artery pressure ranged between 48 and 65 mmHg). Right heart catheterization for the determination of PAP, pulmonary capillary wedge pressure (PCW) and cardiac output (CO) was clinically indicated (diagnostic workup, acute drug testing). Patients accomplished a standardized 10 min mental stress test (computer based, adaptive complex reaction-time task). Pulmonary haemodynamics during stress were compared to resting baseline. During mental stress mean PAP (+/- SEM) increased by 9.4 +/- 2.1 mmHg (P < 0.005). Pulmonary vascular resistance increased by 149 +/- 25 dyne s cm-5 (P < 0.001). Stroke volume decreased by 6.6 +/- 2.2 ml (P < 0.03). The data show that moderate mental stress increases right heart afterload in patients with severe pulmonary hypertension owing to elevation of PVR.

Adult↗
PubMed2000

Disordered calcium homeostasis of sepsis: association with calcitonin precursors.

BACKGROUND: Hypocalcemia and increased serum levels of calcitonin precursors are common in critically ill patients, especially in those with sepsis. We investigated calcium homeostasis in such patients. PATIENTS AND METHODS: Serum concentrations of total and ionized calcium and known factors influencing or reflecting calcium homeostasis were measured in 101 consecutive patients of a medical intensive care unit. Calcitonin precursor levels were determined using a highly sensitive radioimmunoassay. RESULTS: Critical illness per se was associated with decreased serum total and ionized calcium levels, which correlated with the severity of the underlying disease as measured by the APACHE II score. In addition, total and ionized hypocalcemia was more pronounced with increasing severity of infection (P < 0.02), and occurred in parallel with a marked increase of calcitonin precursors (P < 0.001). Mature calcitonin levels, however, remained normal. Changes of serum ionized calcium concentrations from admission to discharge correlated significantly with changes in the serum calcitonin precursor concentration (r2 = - 0.14, P < 0.001). Circulating vitamin D levels, parathyroid hormone levels and other markers reflecting calcium homeostasis did not correlate with the severity of infection. CONCLUSIONS: In critically ill patients with sepsis, markedly elevated circulating calcitonin precursors might play a role in the development of the pronounced hypocalcemia. The specific calcitonin precursor(s) responsible for this effect and the pathophysiological mechanism remain to be elucidated.

Adult↗
PubMed2000

Effect of midazolam on transfer function between beat-to-beat arterial pressure and inter-beat interval length.

Arterial pressure (AP) and inter-beat interval (IBI) length are under autonomic nervous system control. The control mechanisms can be investigated by transfer function analysis. It is not known if this type of analysis may be helpful in monitoring depth of sedation. In an open-label, uncontrolled investigation, the effect of midazolam on the transfer function between AP and IBI, and on spectral indices of AP and heart rate (HR) variability (APV, HRV) were assessed in the absence and presence of the benzodiazepine antagonist flumazenil. We studied 11 healthy male volunteers. After an initial control period of 60 min, we studied three consecutive periods, each of 60 min duration, with progressively increasing concentrations of midazolam (0.02, 0.06, 0.14 mg kg-1 h-1). A final 60-min period during administration of flumazenil 0.004 mg kg-1 h-1 and while the agonist was still present was also studied. To confirm midazolam-induced central nervous system effects, electroencephalography was performed and Ramsay sedation scores were determined. With increasing dose of midazolam, the high frequency (0.15-0.4 Hz) component of the transfer function between AP and IBI decreased progressively (mean 26.5 (SEM 3.7), 19.2 (2.9), 12.8 (1.7), 8.4 (1.6) ms mm Hg-1). This effect was antagonized by flumazenil (21.5 (3.2) ms mm Hg-1). Other indices (e.g. HRV, APV) did not reveal such a clear response to midazolam dose and flumazenil application. Thus in healthy male volunteers, the transfer function between AP and IBI in the parasympathetically dominated high frequency range varies according to benzodiazepine agonism and antagonism. This finding has potential implications for monitoring the effects of benzodiazepines.

Adult↗
PubMed2000

Calcitonin precursors are reliable markers of sepsis in a medical intensive care unit.

OBJECTIVE: The diagnosis of infection in critically ill patients is challenging because traditional markers of infection are often misleading. For example, serum concentrations of calcitonin precursors are increased in patients with infections. However, their predictive accuracy for the diagnosis of sepsis in unselected patients in a medical intensive care unit (ICU) is unknown. Therefore, we compared the usefulness of serum concentrations of calcitonin precursors, C-reactive protein, interleukin-6, and lactate for the diagnosis of sepsis in consecutive patients suffering from a broad range of diseases with an anticipated stay of > or =24 hrs in a medical ICU. DESIGN: Prospective cohort study. SETTING: Medical intensive care unit in a university medical center. PATIENTS: 101 consecutive critically ill patients. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Blood samples were collected at various time points during the course of the disease. Systemic inflammatory response syndrome, sepsis, severe sepsis, and septic shock were diagnosed according to standardized criteria, and patients were reclassified daily without prior knowledge of the serum concentrations of calcitonin precursors or interleukin-6. At admission, 99% of the patients had systemic inflammatory response syndrome, 53% had sepsis, and 5% developed sepsis during their stay in the ICU. Calcitonin precursors, C-reactive protein, interleukin-6, and lactate levels increased with the severity of infection (p < .01, one-way analysis of variance). In a receiver operating characteristic curve analysis, calcitonin precursors were found to be the most reliable laboratory variable for the diagnosis of sepsis as compared with C-reactive protein, interleukin-6, and lactate (p < .01, for each comparison). Calcitonin precursor concentrations of >1 ng/mL had sensitivity of 89% and specificity of 94% for the diagnosis of sepsis. High serum concentrations of calcitonin precursors were associated with poor prognosis (p = .01). CONCLUSIONS: In a medical ICU, serum calcitonin precursor concentrations are more sensitive and are specific markers of sepsis as compared with serum C-reactive protein, interleukin-6, and lactate levels.

Adult↗
PubMed2000

Pressure support and pressure assist/control: are there differences? An evaluation of the newest intensive care unit ventilators.

BACKGROUND: Pressure support (PS) has been widely studied in both patients and lung models, but there is little data available evaluating pressure assist/control (P A/C, frequently referred to as PCV) and no data comparing the operational capabilities of these two modes on the newest generation of ICU ventilators. We used a spontaneously breathing lung model to evaluate the response of the following new generation ventilators to varying inspiratory demand in both PS and P A/C: Bear 1000, Dräger Evita 4, Hamilton Galileo, Nellcor Puritan-Bennett 840 and 740, Siemens Servo 300A, TBird AVS. METHODS: A bellows-in-a-box lung model was set at a respiratory rate of 12 breaths/min, inspiratory time of 1.0 second, and peak inspiratory flows (modified square wave) of 40, 60, and 80 L/min. Each ventilator was set at three levels of PS and P A/C: 10, 15, and 20 cm H(2)O. On all ventilators, flow-triggering was set as sensitive as possible without causing self-triggering. RESULTS: Trigger pressure, trigger pressure-time product, inspiratory trigger time delay, ventilator-delivered peak flow, inspiratory area as a percent of the ideal inspiratory area, expiratory time delay, supraplateau expiratory pressure change, and expiratory area all varied among ventilators and at different lung model peak flows (p < 0.01 and >/= 10% difference). However, PS and P A/C on a given ventilator only differed with regard to expiratory variables (p < 0. 01 and >/= 10% difference). CONCLUSION: In a given ventilator little difference exists in gas delivery and response variables between PS and P A/C, but performance differences do exist among the ventilators evaluated. Ventilator performance is diminished at high lung model peak flows and low pressure settings. (I)), whereas PS gives control over ending inspiration to the patient. What has not been clearly defined is the gas delivery and ventilator response differences, if any, between these two (PS and P A/C) pressure targeted assist modes. Most new generation intensive care unit (ICU) ventilators provide both pressure support (PS) and pressure assist/control (P A/C) ventilation.19,20 The specific operational difference between these two modes is the mechanism that transitions inspiration to expiration. With pressure support the primary mechanism is a decrease in peak inspiratory flow to a predetermined level, whereas with P A/C mechanical T(I) is preset.19,20 We compared the operation of seven of the newest generation ICU ventilators in a spontaneously breathing lung model in both PS and P A/C. We hypothesized that there would be no difference in variables assessed between PS and P A/C except for the transition to expiration and that there would be no difference in response among ventilators evaluated.

Equipment Safety↗
PubMed1999

Reversible cerebral ischemia in patients with pheochromocytoma.

Cerebral ischemia and symptoms of stroke can occur as a rare manifestation in patients with pheochromocytoma. We describe a 45-year-old woman who was admitted because of a right-sided hemiparesis due to an ischemic lesion in the left hypothalamus. The clinical diagnosis of a pheochromocytoma was proven by highly elevated urinary catecholamines and confirmed histologically after operation. The successful removal of the tumor led to the almost complete recovery of the neurological deficiencies. It is of vital importance to know this atypical presentation of pheochromocytoma. The diagnosis of pheochromocytoma should be suspected in patients with focal cerebral symptoms, particularly in the presence of intermittent hypertension or other paroxysmal symptoms suggestive of pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1999

Additional inspiratory work of breathing imposed by tracheostomy tubes and non-ideal ventilator properties in critically ill patients.

OBJECTIVE: To determine the tracheostomy tube-related additional work of breathing (WOBadd) in critically ill patients and to show its reduction by different ventilatory modes. DESIGN: Prospective, clinical study. SETTING: Medical ICU of a university teaching hospital. INTERVENTION: Standard tracheostomy due to prolonged respiratory failure. MEASUREMENTS AND RESULTS: Ten tracheostomized, spontaneously breathing patients were investigated. As the tube resistance depends on gas flow, patients were subdivided according to minute ventilation into a low ventilation group (= 10 l/min; n = 5) and a high ventilation group (> 10 l/min; n = 5). The WOBadd due to tube resistance and non-ideal ventilator properties was calculated on the basis of the tracheal pressure measured. Ventilatory modes investigated were: continuous positive airway pressure (CPAP), inspiratory pressure support (IPS) of 5, 10, and 15 cm H2O above PEEP, and automatic tube compensation (ATC). In the low ventilation group, WOBadd during CPAP was 0.382+/-0.106 J/l. It was reduced to below 15% of that value by ATC or IPS more than 5 cm H2O. In the high ventilation group WOBadd during CPAP increased to 0.908+/-0.142 J/l. In this group, however, only ATC was able to reduce WOBadd below 15% of the value observed in the CPAP mode. CONCLUSIONS: The results indicate that, depending on respiratory flow rate, (1) tracheostomy tubes can cause a considerable amount of WOBadd, and (2) ATC, in contrast to IPS, is a suitable mode to compensate for WOBadd at any ventilatory effort of the patient.

Aged↗
PubMed1999

Midazolam effects on prepulse inhibition of the acoustic blink reflex.

AIMS: The eye-blink response following sudden acoustic noise bursts is part of the startle reflex. The magnitude of the startle response can be attenuated by presentation of a weak stimulus before the 'startle-eliciting' stimulus (prepulse inhibition, PPI). PPI is a stable finding in awake humans but may be altered by anaesthetic drugs. We investigated whether the application of benzodiazepines altered the magnitude of PPI in healthy male volunteers. METHODS: In an open-label noncontrolled investigation, the effect of the benzodiazepine agonist midazolam on PPI was assessed in the absence and presence of the antagonist flumazenil. After an initial control period of 60 min three consecutive periods, each of 60 min, with progressively increasing concentrations of midazolam were studied (0. 02, 0.06, 0.14 mg kg-1 h-1 ). A final 60 min period during the administration of flumazenil (0.004 mg kg-1 h-1 ) and while the agonist was still present was also studied. Drug was administered intravenuously as a combination of bolus, 50% of total dose and continuous infusion over the 60 min period. Electromyographic (EMG) response of the right orbicularis oculi muscle was used to assess the startle response to noise bursts of 50 ms duration (95 dB(A)). Noise bursts were randomly preceded by nonstartling prepulses (800 Hz sinus, 50 ms duration, 65 dB(A), prepulse to noise interval 120 ms). The magnitude of PPI was calculated by dividing the EMG response to nonprepulsed stimuli by the response to prepulsed stimuli for each individual and period. Eleven subjects participated in the study, two of them were excluded from the statistical analysis because startle responses could not be reliably elicited (final sample size n=9). RESULTS: The magnitude of PPI was inversely related to the concentration of midazolam. This relationship was described by a sigmoidal Emax model, giving an Emax of 0.65+/-0.13, an ED50 of 33.9+/-10.9 ng ml-1 and gamma of 3.5+/-1.0. During infusion of flumazenil and in the presence of midazolam, the magnitude of PPI increased by 0.11 (95% CI, 0-0.22, P</=0.04), which is consistent with its mode of action as a benzodiazepine antagonist. CONCLUSIONS: In healthy male volunteers the magnitude of PPI varies according to agonism and antagonism of benzodiazepine receptors, suggesting that the assessment of PPI may be potentially useful to monitor the sedative effect of benzodiazepines in the clinical setting.

Acoustic Stimulation↗
PubMed1999

Effect of beta blockade with and without sympathomimetic activity (ISA) on sympathovagal balance and baroreflex sensitivity.

Beta blockers increase heart rate variability (HRV) and improve survival in coronary artery disease (CAD). The benefit of beta blockers with intrinsic sympathomimetic activity (ISA) in CAD still remains a matter of debate, and their effect on HRV has not yet been investigated. Therefore, we measured HRV, systolic blood pressure variability (BPV) and baroreflex sensitivity (BRS) under propranolol (PROP, without ISA, 160 mg q.d.), pindolol (PIN, with potent ISA, 15 mg q.d.) and placebo (PLA, q.d.) in 30 healthy subjects, aged 21-39 years, during controlled frequency breathing (0.30 Hz) in supine and tilt positions. PROP increased HRV in the high-frequency (0.15-0.40 Hz) band (PROP 7.4 +/- 1.0; PLA 6.9 +/- 1.4; PIN 6.8 +/- 1.0 ln MI2; P = 0.003), decreased BPV in the low-frequency band (at 0.1 Hz, Mayer waves) (PROP 0.6 +/- 0.7; PLA 1.3 +/- 1.1; PIN 1.2 +/- 1.2 ln mmHg2; P = 0.001) and enhanced BRS (PROP 14.6 +/- 9.5; PLA 8.0 +/- 6.8; PIN 8.7 +/- 6.8 ms mmHg-1; P = 0.001) in the supine position. After passive tilt, PROP decreased HRV in the low-frequency band (PROP 6.1 +/- 0.9; PLA 6.5 +/- 1.1; PIN 6.9 +/- 0.7 ln MI2; P < 0.001) and decreased Mayer waves (PROP 1.8 +/- 0.8; PLA 2.4 +/- 1.0; PIN 2.7 +/- 0.8 ln mm Hg2; P < 0.001). PIN increased the low-frequency HRV response, which is induced by passive tilt (PIN + 0.9 +/- 1.0; PLA + 0.3 +/- 1.3, PROP + 0.3 +/- 1.0 ln MI2; P = 0.026). Our results prove that beta-adrenergic blockade with potent ISA does not increase HRV, has no beneficial effect on autonomic balance and even exaggerates sympathetic responses to passive tilt.

Adrenergic beta-Antagonists↗
PubMed1999

[Value of German Hospital Diagnosis Statistics in epidemiology-- an analysis with subarachnoid hemorrhage as an example].

Due to the Hospital Statistics Regulations of the 10th April 1990, the German Hospital Diagnosis Statistics were introduced in 1993 with the intention to serve as a database of health care decisions. This purpose requires a high-quality collection of epidemiologically relevant data. From 1993 to 1996 we analysed the datasets obtainable for subarachnoid haemorrhage which is coded with ICD 430. A subset concerning the data of 1996 and the Saarland region was compared to the data of the Saarland medical school at Homburg/Saar. Cases treated in the neurosurgical department were critically reviewed. About 20% of the cases coded with ICD 430 showed no subarachnoid haemorrhage. On the other hand, again about 20% of subarachnoid haemorrhage cases were not coded with ICD 430. The statistics comprise duplicates due to transfers between hospitals. The calculation of incidence is not possible because new bleeding cases cannot be outlined. In the present form the German Hospital Diagnosis Statistics are not suitable as a reliable base of health care decisions. This is partly caused by the inadequacy of the ICD-classification but, also, by the criteria for collecting data. We propose several modifications which can improve data quality in order to meet the intended requirements.

Databases, Factual↗
PubMed1998

[Intensive monitoring of patients with acute cerebral ischemia within the scope of a coordinated stroke treatment concept: initial experiences].

QUESTIONS UNDER STUDY: It has been shown that the prognosis of patients with stroke can be improved by specialized stroke units. Whether any additional benefit can be achieved by use of intensive care resources is unknown. Therefore, it was the purpose of this study to analyze our first experience of management of patients with acute ischaemic stroke in an intensive care unit, as part of a newly implemented coordinated stroke concept. METHODS: A consecutive series of 88 patients with acute ischemic stroke (age 64.4 +/- 14.2 years, 28% females) hospitalized in a medical intensive care unit according to predefined criteria formed the study population. The goals were to monitor vital functions, to complete diagnostic studies in timely fashion and to prevent and treat complications. RESULTS: The patients were hospitalized in the intensive care unit for a mean period of 34.4 +/- 19.5 hours. Relevant pathologic findings included systolic hypertension > 220 mm Hg in 5% and permanent or intermittent relative systolic hypotension < 150 mm Hg in 25% and 98% of patients respectively. One patient (1%) died during the stay. Additional diagnostic studies were performed more often in patients with progressive or fluctuating symptoms (100% of patients in each group) than in those with improving or stable symptoms (50% of patients in each group). Fourteen percent of patients were treated for hypertension and 30% for hypotension. Antithrombotic therapy with aspirin was started in 34%, prophylaxis for venous thrombosis with low dose heparin in 39% and systemic anticoagulation in 40% of patients respectively. No cardiac or pulmonary complications requiring treatment were observed and no specific therapies for neurologic complications were utilized. At the time of discharge from the intensive care unit, 88% of patients showed improved or stable neurologic findings. CONCLUSIONS: In the present analysis, an unexpectedly high incidence of relative arterial hypotension was observed in patients hospitalized in an intensive care unit for acute ischaemic stroke. Therapeutic measures were restricted mainly to blood pressure control and anticoagulation/antithrombotic treatment. Specific therapies for neurologic complications or interventions requiring the resources of an intensive care unit were not used. Whether defined patient groups with ischaemic stroke will benefit from specific treatment in an intensive care unit needs to be tested by controlled, randomized studies.

Acute Disease↗
PubMed1998

Expiratory phase and volume-adjusted tracheal gas insufflation: a lung model study.

OBJECTIVE: To evaluate in a lung model the effects of expiratory-phase tracheal gas insufflation (expiratory-phase TGI) with both volume and pressure control ventilation, and tidal volume-adjusted continuous flow TGI (volume-adjusted TGI) on system pressures and volumes. DESIGN: Single-compartment lung model. SETTING: Research laboratory in a university medical center. INTERVENTIONS: Expiratory-phase TGI was established, using a solenoid valve activated by the ventilator. Volume-adjusted TGI was applied by reducing tidal volume (VT) by the product of TGI flow and inspiratory time. Ventilation was provided with pressure control of 20 cm H2O or volume control ventilation with VT similar to that with pressure control ventilation. A rate of 15 breaths/min and positive end-expiratory pressure (PEEP) of 10 cm H2O were used throughout. Inspiratory time periods of 1.0, 1.5, 2.0, and 2.5 secs were used with TGI flows of 0, 4, 8, and 12 L/min. Lung model compliance (mL/cm H2O) and resistance (cm H2O/L/sec) combinations of 20/20, 20/5, and 50/20 were used. MEASUREMENTS AND MAIN RESULTS: In expiratory-phase TGI with pressure control ventilation, peak alveolar pressure remained constant, PEEP increased (p < .01) and VT decreased (p < .01). In expiratory-phase TGI with volume control ventilation and volume-adjusted TGI, there were significant increases in peak alveolar pressure and PEEP (p < .01). Readjustment of VT in volume-adjusted TGI was impossible with longer inspiratory time (> or = 2 secs) and higher TGI flows (> or = 8 L/min). CONCLUSIONS: The marked increases in system pressures and volumes observed with continuous-flow TGI can be avoided with expiratory-phase TGI and volume-adjusted TGI.

Insufflation↗
PubMed1997

Long-term prognosis of young patients after myocardial infarction in the thrombolytic era.

BACKGROUND: Myocardial infarction (MI) in young adults is a rare event. In the Framingham study, the 10-year incidence rate of MI per 1,000 was 12.9 in men 30-34 years old. Overall, 4-8% of patients with acute MI are < or = 40 years old. HYPOTHESIS: It was the purpose of this study to assess the in-hospital and long-term morbidity and mortality in patients < or = 40 years old with acute myocardial infarction compared with older patients in the thrombolytic era. METHODS: A consecutive series of 75 patients aged < or = 40 years (mean 35.0 +/- 4.8) with acute myocardial infarction was compared with an equally sized group of patients aged > 40 years (mean 65.1 +/- 9.8). RESULTS: Thrombolysis or direct percutaneous transluminal coronary angioplasty was performed in 52 versus 24% (p = 0.0004) and 5.3 versus 2.7% (p = NS) in younger and older patients, respectively. Significantly fewer young patients had multivessel disease (28 vs. 64%, p < 0.004). No in-hospital mortality was observed in patients with reperfusion therapy irrespective of age. After a mean followup time of 47 +/- 35 months, cardiac mortality was 0 and 11% (p < 0.03), respectively, in young and older patients with, and 3 versus 24% (p < 0.02) without reperfusion therapy, respectively. In addition, significantly fewer patients in the younger age group developed recurrent angina pectoris (12 vs. 39%, p = 0.0004) or congestive heart failure (9 vs. 34%, p = 0.0005) irrespective of reperfusion therapy. CONCLUSION: Our observations demonstrate that long-term prognosis after myocardial infarction in young patients is excellent in the thrombolytic era.

Adult↗