Biomedical subjects

H Sonntag

Publications and source records attributed to H Sonntag.

At least 19 recordsLinked to original sources

PubMed2001

The natural course of cannabis use, abuse and dependence over four years: a longitudinal community study of adolescents and young adults.

OBJECTIVES: To determine incidence and patterns of natural course of cannabis use and disorders as well as cohort effects in a community sample of adolescents and young adults. METHOD: Cumulative incidence and patterns of cannabis use and disorders were examined in a prospective longitudinal design (mean follow-up period=42 months) in a representative sample (N=2446) aged 14-24 years at the outset of the study. Patterns of cannabis use, abuse and dependence (DSM-IV) were assessed with the Composite International Diagnostic Interview (M-CIDI). RESULTS: (1) Cumulative lifetime incidence for cannabis use (at second follow-up): 47%; 5.5% for cannabis abuse, 2.2% for dependence. (2) Men used and abused cannabis more often than women. (3) The majority of the older participants (18-24 years at baseline) had reduced their cannabis use at follow-up, while younger participants (14-17 years at baseline) more often had increased their use and developed abuse or dependence. (4) The younger birth cohort (1977-1981) tended to start earlier with substance (ab)use compared to the older birth cohort (1970-1977). (5) Cannabis use was associated with increasing rates of concomitant use of other licit and illicit drugs. CONCLUSIONS: Cannabis use is widespread in our sample, but the probability of developing cannabis abuse or dependence is relatively low (8%). The natural course of cannabis use is quite variable: about half of all cannabis users stopped their use spontaneously in their twenties, others report occasional or more frequent use of cannabis.

Adolescent↗

PubMed2001

Autovaccination of dairy cows to treat post partum metritis caused by Actinomyces pyogenes.

Autovaccines are therapeutic vaccines manufactured from a disease causing micro-organism for individual treatment of patients, animals, or sometimes herds to treat chronic or recurrent infections. Despite the common use of autovaccines in veterinary medicine, their mechanism of action, i.e. the immunologic effector mechanism activated after administration, has never been investigated. Here we present data concerning the use of autovaccines to treat metritis infection in a group of dairy cows. Following autovaccination we observed a significant decrease in CD4+ cells paralleled by an increase in T-cells expressing the gammadelta-T-cell receptor (gammadelta-TCR) in the peripheral blood of the treated animals. Lymphocyte proliferation assays showed an initial increase in antigen-specific responsiveness followed by a decrease in this responsiveness during autovaccination treatment. We therefore conclude that administration of an autovaccine leads to the activation of immunologic effector mechanisms which contribute to recovery of the diseased animals.

Actinomyces↗

PubMed2001

Changes in cardiac output and intrathoracic blood volume: a mathematical coupling of data?

BACKGROUND: Measurements of intrathoracic blood volume (ITBV) provide volumetric information about cardiac preload and are used to investigate the cause of alterations in cardiac output (CO). On the other hand, CO is required to calculate ITBV. Thus, concerns have been raised with respect to a mathematical coupling of data. The aim of this prospective, clinical study was to investigate whether a variation in CO induced by high-dose beta-blockade influences thermodilution measurements of ITBV in the absence of changes in intravascular volume in patients undergoing minimally invasive coronary artery bypass grafting. METHODS: Sixteen patients undergoing elective minimally invasive direct coronay artery bypass (MIDCAB) surgery were studied. Transpulmonary thermodilution measurements of ITBV and CO were simultaneously performed before bypass grafting, during beta-blockade induced by high-dose esmolol and at the end of surgery. RESULTS: During esmolol administration, CO significantly decreased by 33%, whereas ITBV remained unchanged compared to control values (876+/-46 ml m-2 during control versus 860+/-61 ml m-2 during esmolol administration). After the end of esmolol administration, CO significantly increased by 79%. Again, ITBV remained virtually unchanged (860+/-61 ml m-2 during esmolol administration versus 911+/-38 ml m-2 after esmolol administration). CONCLUSIONS: The results of the present study demonstrate that substantial alterations in CO as a consequence of high-dose esmolol infusion are not associated with changes in ITBV. Because haemodynamic changes were induced by factors other than variation of preload, these findings suggest that changes in cardiac output do not influence thermodilution measurements of ITBV in this setting.

Adrenergic beta-Antagonists↗

PubMed2001

Assessment of cardiac preload by indicator dilution and transoesophageal echocardiography.

BACKGROUND AND OBJECTIVE: Assessment of cardiac preload is of major importance in the management of critically ill patients. Echocardiographic determined left ventricular end-diastolic area and indicator dilution derived intrathoracic blood volume are used as surrogates for cardiac preload. However, no controlled comparison studies on the relationship between induced changes in end-diastolic area and intrathoracic blood volume and concomitant changes in stroke volume index are available. METHODS: The effects of a change in body position on these variables were investigated in 10 anaesthetized patients. RESULTS: Intrathoracic blood volume and end-diastolic area decreased by 18 +/- 11% and 27 +/- 13% respectively. Stroke volume index concomitantly decreased by 19 +/- 11%. Correlation analysis revealed a close relation between stroke volume index and intrathoracic blood volume (r=0.75) and end-diastolic area (r=0.76). CONCLUSIONS: Within the observed range of data, intrathoracic blood volume and end-diastolic area are equivalent indices of cardiac preload.

Adult↗

PubMed2001

Reliability of cerebral blood flow measurements by transcerebral double-indicator dilution technique.

BACKGROUND AND OBJECTIVE: The recently developed transcerebral double-indicator dilution technique has proven to be a feasible monitoring alternative to measure global cerebral blood flow at the bedside. However, the short-term repeatability of transcerebral double-indicator dilution measurements has not yet been investigated. The present study was designed to investigate the accuracy in terms of reliability for repeated transcerebral double-indicator dilution measurements to assess global cerebral blood flow during a definite carbon dioxide challenge in a clinical trial. METHODS: The investigation was performed in 10 patients scheduled for elective coronary artery bypass grafting. After induction of anaesthesia, repeated cerebral blood flow measurements using transcerebral double-indicator dilution were performed during target normocapnia, hypocapnia and hypercapnia. For transcerebral double-indicator dilution measurements, a bolus injection of ice-cold indocyanine green was administered into a central vein. The resulting thermal dye dilution curves were recorded simultaneously in the aorta and the jugular bulb using combined fibreoptic thermistor catheters. Cerebral blood flow was calculated from the mean transit times of the indicators through the brain. Additionally, transcranial Doppler sonography was simultaneously performed to measure transient changes in the cerebral blood flow velocity. RESULTS: Transcerebral double-indicator dilution measurements revealed a reasonable coefficient of repeatability with 9.1, 9.7 and 20.2 mL min-1 100 g-1 during normo-, hypo- and hypercapnic conditions, respectively. However, a total of 20% of the administered measurements had to be rejected for methodological reasons. CONCLUSIONS: Repeated measurements with the transcerebral double-indicator dilution method show a reasonable repeatability. With consideration to the limitations of the transcerebral double-indicator dilution technique, this new method proves to be a reliable monitoring tool to measure global cerebral blood flow at the bedside.

Aged↗

PubMed2000

Are social fears and DSM-IV social anxiety disorder associated with smoking and nicotine dependence in adolescents and young adults?

To investigate associations between social anxiety and smoking behaviour in order to explore whether social anxiety predicts the first onset of cigarette smoking, regular smoking and the development of nicotine dependence. Baseline and four-year follow-up data from the Early Developmental Stages of Psychopathology Study (EDSP), a prospective-longitudinal community study of 3,021 adolescents and young adults, are used. Smoking behaviour and psychopathology were assessed with the M-CIDI and its DSM-IV algorithms. At baseline, 35.7% of the sample were regular smokers, and 18.7% fulfilled criteria for DSM-IV nicotine dependence. Twenty-seven point two percent reported at least one social fear, and 7.2% met criteria for DSM-IV social phobia, most of whom reported first onset of social fear problems clearly prior to smoking initiation. Cross-sectional retrospective baseline analyses based on retrospective reports revealed that social fears and DSM-IV social phobia were both significantly associated with higher rates of nicotine dependence. Prospective-longitudinal analyses that were conducted in an attempt to confirm cross-sectional retrospective results showed that baseline non-users with social fears (OR = 3.85) and baseline non-dependent users with social fears (OR = 1.5) had an increased risk of onset of nicotine dependence during the follow-up period of four years. These findings remained significant even when controlling for co-morbid depressive disorders. Social anxiety was found to be significantly associated with nicotine dependence in both cross-sectional retrospective and prospective-longitudinal analyses. It is suggested that social fears could lead to heavy tobacco use as smoking is a socially acceptable behaviour that relieves anxiety in social situations. Possible differential effects of social anxiety on the early stages of smoking behaviour compared to effects on nicotine dependence are discussed. These findings should stimulate a continued search into potentially causal links between social fear symptoms and the development of tobacco consumption and nicotine dependence in adolescence.

Adolescent↗

PubMed2000

Disability and quality of life in pure and comorbid social phobia. Findings from a controlled study.

Social phobia is increasingly recognized as a prevalent and socially impairing mental disorder. However, little data is available regarding the general and disease-specific impairments and disabilities associated with social phobia. Furthermore, most studies have not controlled for the confounding effects of comorbid conditions. This study investigates: (a) the generic quality of life; (b) work productivity; and, (c) various other disorder-specific social impairments in current cases with pure (n = 65), comorbid (n = 51) and subthreshold (n = 34) DSM-IV social phobia as compared to controls with no social phobia (subjects with a history of herpes infections). Social phobia cases reported a mean illness duration of 22.9 years with onset in childhood or adolescence. Current quality of life, as assessed by the SF-36, was significantly reduced in all social phobia groups, particularly in the scales measuring vitality, general health, mental health, role limitations due to emotional health, and social functioning. Comorbid cases revealed more severe reductions than pure and subthreshold social phobics. Findings from the Liebowitz self-rated disability scale indicated that: (a) social phobia affects most areas of life, but in particular education, career, and romantic relationship; (b) the presence of past and current comorbid conditions increases the frequency and severity of disease-specific impairments; and, (c) subthreshold social phobia revealed slightly lower overall impairments than comorbid social phobics. Past-week work productivity of social phobics was significantly diminished as indicated by: (a) a three-fold higher rate of unemployed cases; (b) elevated rates of work hours missed due to social phobia problems; and (c) a reduced work performance. Overall, these findings underline that social phobia in our sample of adults, whether comorbid, subthreshold, or pure was a persisting and impairing condition, resulting in considerable subjective suffering and negative impact on work performance and social relationships. The current disabilities and impairments were usually less pronounced than in the past, presumably due to adaptive behaviors in life style of the respondents. Data also confirmed that social phobia is poorly recognized and rarely treated by the mental health system.

Adult↗

PubMed2000

The endogenous pathway is a major route for deep sternal wound infection.

OBJECTIVE: Deep wound infections pose an increasing problem in cardiac surgery patients. Prospective infection monitoring is thus a means of identifying possible risk factors. METHODS: Within a period of 5 months, a total of 376 adult patients, 260 men and 116 women, with a mean age of 62.6 years (range 18-88), underwent coronary bypass grafting (n=281) or other cardiac surgery procedures (n=95). Nasal cultures were taken preoperatively from every patient, as well as cultures of the wound during surgery and when dressings were changed thereafter. In addition, nasal cultures were taken from all the medical and nursing staff. To differentiate endogenous and exogenous infection pathways, DNA fingerprint analysis was performed. RESULTS: A total of 38 patients (10.1%) developed a wound infection, in 14 patients this happened to be a deep wound infection, in 24 patients a superficial one. Five sternal wound infections were associated with mediastinitis (1.3%). The occurrence of a wound infection overall resulted in prolonged hospitalization (29.4+/-24 vs. 11.9+/-6.9 days, P=0.001), but not in increased hospital mortality (4.4% vs. 3.9%). Obesity, diabetes mellitus and nasal carriage of Staphylococcus aureus proved to be independent risk factors with an odds ratio of 2.07, 2.26 and 2.28, respectively. In all but one of the sternal colonizations with S. aureus, DNA fingerprint analysis demonstrated an identical pattern of S. aureus from the patient's nose and sternum, indicating an endogenous infection pathway. CONCLUSIONS: The determination of the endogenous pathway for severe wound infection makes prevention possible by means of preoperative local S. aureus eradication.

Adult↗

PubMed2000

Comparison of ventilatory and haemodynamic effects of BIPAP and S-IMV/PSV for postoperative short-term ventilation in patients after coronary artery bypass grafting.

The aim of the present multiple cross-over study was to compare the effects of biphasic positive airway pressure (BIPAP) ventilation with synchronized intermittent mandatory ventilation combined with pressure support ventilation (S-IMV/PSV) in sedated and awake patients after coronary artery bypass grafting (CABG) surgery. Twenty-four patients with no evidence of preoperative respiratory dysfunction and an uncomplicated intraoperative course were investigated. The patients were randomly assigned to one of two groups starting with either BIPAP or S-IMV/PSV mode. Haemodynamic measurements and blood gas analyses were performed during sedation with 2.0 mg kg(-1) h(-1) propofol in the primary mode, after switching to the alternative ventilatory mode, and in the primary mode again. The same sequence of measurements was repeated in awake patients who had reached extubation criteria. In awake patients, PSV was performed instead of S-IMV. Statistical analysis of data was performed using non-parametric tests. Inspiratory peak pressure increased significantly during S-IMV/PSV in sedated patients in both groups. Other ventilatory parameters did not differ significantly between BIPAP and S-IMV/PSV in both groups. Similarly, haemodynamic parameters and blood-gas analyses did not vary with the ventilatory mode. Our results demonstrate that BIPAP ventilation has comparable effects on haemodynamics and pulmonary gas exchange compared with S-IMV/PSV and PSV when used for short-term ventilatory support in patients after cardiac surgery.

Aged↗

PubMed2000

Doppler-sonographic evidence of cerebral microembolism originating from a biventricular assist device.

The use of extracorporeal assist devices in heart failure is associated with the risk of thromboembolic complications [1]. Prove of thromboembolic material in the ventricles and tubes of the assist devices is difficult, and the clinical relevance of thrombotic material in the tubes is not clear. Here, we report on a patient with severe heart failure caused by endstage dilated cardiomyopathy who was bridged to transplantation using a biventricular assist device (BVAD). Five weeks after implantation, transcranial Doppler sonography (TCD) revealed high intensity transient signals (HITS) in basal cerebral arteries, suggesting continued cerebral microembolism. Apart from a correlation of these Doppler sonographic findings with neurological symptoms, macroscopic evidence of fibrin thrombi in the artificial ventricle, and post mortem confirmation of cerebral infarction could be proved.

Adult↗

PubMed2000

Myocardial consequences of remifentanil in patients with coronary artery disease.

Remifentanil may be an alternative to conventional opioids for minimally invasive direct coronary artery bypass surgery because of its extremely short duration of action. The aim of this study was to investigate the effects of remifentanil on myocardial blood flow, metabolism and systemic haemodynamic variables in patients with coronary artery disease. After approval by the local ethics committee, 12 male patients were investigated before elective coronary artery bypass grafting. Systemic haemodynamic variables, myocardial blood flow and metabolism were measured when patients were awake and when they were anaesthetized with high-dose remifentanil (2.0 micrograms kg-1 min-1), or with remifentanil 0.5 microgram kg-1 min-1 combined with propofol (target-controlled infusion aiming at a plasma concentration of 2.0 micrograms ml-1). Myocardial blood flow was measured using a modified Kety-Schmidt technique. High-dose remifentanil anaesthesia significantly reduced cardiac index (CI) (-25%) as a consequence of a decrease in stroke volume index (SVI) (-14%) and heart rate (-13%). Mean arterial pressure (MAP) was 30% lower than that in the awake patient. Myocardial blood flow and myocardial oxygen uptake (MVO2) decreased by 30% and 42%, respectively. In contrast to high-dose remifentanil anaesthesia, systemic vascular resistance index (-14%) during remifentanil/propofol anaesthesia was significantly lower than that in the awake patient. Other haemodynamic variables, and myocardial blood flow and MVO2, did not significantly differ from the high-dose remifentanil period. In conclusion, high-dose remifentanil reduces SVI, heart rate, MAP, myocardial blood flow and MVO2 and its effects do not differ from those of remifentanil/propofol anaesthesia.

Aged↗

PubMed2000

Effects of the sitting position on the distribution of blood volume in patients undergoing neurosurgical procedures.

The use of the sitting position in neurosurgery is often associated with decreased arterial pressure (MAP) and stroke volume index (SVI). A shift in blood from the intra- to the extrathoracic compartment may be responsible for this cardiovascular response. However, little is known of the amount of shift in blood volume after transfer from the supine to the sitting position. Therefore, we measured simultaneously changes in intrathoracic blood volume (ITBV) caused by a change in body position in anaesthetized patients. Measurements of cardiac index (CI), ITBV, pulmonary (PBV) and total circulating (TBVcirc) blood volumes were performed in the supine and sitting position. CI, ITBV, PBV and TBVcirc were measured using a thermodye dilution technique. Fluid input was restricted to 14 ml kg-1 before induction of anaesthesia. Change in body position caused a significant decrease in ITBV and was accompanied by a significant decrease in CI, SVI and MAP. Changes in ITBV correlated (r = 0.78) with changes in SVI. Thus a change in blood volume distribution between the intra- and extrathoracic compartment occurred after a change from the supine to the sitting position. Indicator dilution enables quantification of this shift and may be helpful in guiding fluid therapy in selected patients.

Adult↗

PubMed2000

Cerebrovascular tone rather than intracranial pressure determines the effective downstream pressure of the cerebral circulation in the absence of intracranial hypertension.

Cerebral perfusion pressure is commonly calculated from the difference between mean arterial pressure and intracranial pressure because intracranial pressure is known to represent the effective downstream pressure of the cerebral circulation. Studies of other organs, however, have shown that effective downstream pressure is determined by a critical closing pressure located at the arteriolar level. This study was designed to investigate the effects of PCO2-induced variations in cerebrovascular tone on the effective downstream pressure of the cerebral circulation. Sixteen patients recovering from head injury were studied. Intracranial pressure was assessed by epidural pressure transducers. Blood flow velocity in the middle cerebral artery was monitored by transcranial Doppler sonography. Effective downstream pressure was derived from the zero flow pressure as extrapolated by regression analysis of instantaneous arterial pressure/middle cerebral artery flow velocity relationships. PaCO2 was varied between 30 and 47 mm Hg in randomized sequence. Intracranial pressure decreased from 18.5+/-5.2 mm Hg during hypercapnia to 9.9+/-3.1 mm Hg during hypocapnia. In contrast, effective downstream pressure increased from 13.7+/-9.6 mm Hg to 23.4+/-8.6 mm Hg and exceeded intracranial pressure at hypocapnic PaCO2 levels. Our results demonstrate that, in the absence of intracranial hypertension, intracranial pressure does not necessarily represent the effective downstream pressure of the cerebral circulation. Instead, the tone of cerebral resistance vessels seems to determine effective downstream pressure. This suggests a modified model of the cerebral circulation based on the existence of two Starling resistors in a series connection.

Adult↗

PubMed1999

Disability and quality of life in pure and comorbid social phobia--findings from a controlled study.

Social phobia is increasingly recognized as a prevalent and socially impairing mental disorder. However, little data is available regarding the general and disease-specific impairments and disabilities associated with social phobia. Furthermore, most studies have not controlled for the confounding effects of comorbid conditions. This study investigates: (a) the generic quality of life; (b) work productivity; and, (c) various other disorder-specific social impairments in current cases with pure (n = 65), comorbid (n = 51) and subthreshold (n = 34) DSM-IV social phobia as compared to controls with no social phobia (subjects with a history of herpes infections). Social phobia cases reported a mean illness duration of 22.9 years with onset in childhood or adolescence. Current quality of life, as assessed by the SF-36, was significantly reduced in all social phobia groups, particularly in the scales measuring vitality, general health, mental health, role limitations due to emotional health, and social functioning. Comorbid cases revealed more severe reductions than pure and subthreshold social phobics. Findings from the Liebowitz self-rated disability scale indicated that: (a) social phobia affects most areas of life, but in particular education, career, and romantic relationship; (b) the presence of past and current comorbid conditions increases the frequency of disease-specific impairments; and, (c) subthreshold social phobia revealed slightly lower overall impairments than comorbid social phobics. Past week work productivity of social phobics was significantly diminished as indicated by: (a) a three-fold higher rate of unemployed cases; (b) elevated rates of work hours missed due to social phobia problems; and, (c) a reduced work performance. Overall, these findings underline that social phobia in our sample of adults, whether comorbid, subthreshold, or pure was a persisting and impairing condition, resulting in considerable subjective suffering and negative impact on work performance and social relationships. The current disabilities and impairments were usually less pronounced than in the past, presumably due to adaptive behaviors in life style of the respondents. Data also confirmed that social phobia is poorly recognized and rarely treated by the mental health system.

Adult↗

PubMed1999

Comparison of cardiac output assessed by pulse-contour analysis and thermodilution in patients undergoing minimally invasive direct coronary artery bypass grafting.

OBJECTIVE: To investigate the precision and accuracy of continuous pulse contour cardiac output (PCCO) compared with intermittent transcardiopulmonary (TCPCO) and pulmonary artery thermodilution (TDCO) measurements in patients undergoing minimally invasive coronary bypass surgery (MIDCAB). DESIGN: Prospective, controlled, clinical study. SETTING: University hospital. PARTICIPANTS: Twelve patients undergoing MIDCAB. INTERVENTIONS: Thirty-six measurements of PCCO and thermodilution cardiac output (CO) were simultaneously performed after the start of surgery, during bypass grafting, and at the end of surgery. TCPCO and TDCO were simultaneously assessed by three injections of ice-cold saline randomly spread over the respiratory cycle. The pulse contour device was initially calibrated with an additional set of aortic thermodilution measurements. MEASUREMENTS AND MAIN RESULTS: Absolute values of CO ranged between 1.6 and 9.2 L/min. A close agreement among the three techniques was observed at all measurements. Mean bias between PCCO and TDCO and TCPCO was 0.003 L/min (2 SD of differences between methods = 1.26 L/min) and 0.27 L/min (2 SD of differences between methods = 1.16 L/min), respectively. The correlation coefficients were r2 = 0.90 for TCPCO versus PCCO and r2 = 0.88 for TDCO versus PCCO. CONCLUSION: The results of the present study show that compared with thermodilution CO, pulse contour analysis enables accurate measurement of continuous CO in patients undergoing MIDCAB.

Cardiac Output↗

PubMed1999

Patterns of cannabis use, abuse and dependence over time: incidence, progression and stability in a sample of 1228 adolescents.

AIMS: To present data on the incidence of cannabis use at follow-up, and its progression, stability, abuse and dependence in a representative sample of adolescents (N = 1228), aged 14-17 years at "baseline"--the outset of the study--in Munich, Germany. DESIGN: The study employed a prospective longitudinal design using a representative population sample. The mean follow-up time was 19.7 months. The Composite International Diagnostic Interview (M-CIDI) was used to assess patterns of use, abuse and dependence according to DSM-IV criteria. FINDINGS: (1) In our sample, 34.8% of males and 30.2% of females had tried cannabinoids at least once. (2) Of those who used cannabis repeatedly (two or four times) at baseline, 26.1% stopped using by follow-up; the majority went on to regular use in the follow-up period. Similarly, only 17.7% of the regular users at the outset stopped using cannabis completely; 74.2% continued their pattern of regular use. Thus, the higher the baseline use pattern, the higher was the probability of continued or heavier use during follow-up. (3) Although the cumulative life-time incidence for DSM-IV cannabis abuse (3.5%) in this age group was low, it is noteworthy that complete diagnostic remissions were relatively rare (31.7% for dependence, 41.1% for abuse). (4) There was considerable concurrent use of other drugs. CONCLUSIONS: Cannabis use was almost as widespread in this sample of adolescents in Germany as in similar age groups in metropolitan areas of North America. There was a relatively low spontaneous remission rate among regular and repeated users. Cannabis use in adolescence appears to be less transient than many people would believe.

Adolescent↗

PubMed1999

Covariates of cannabis use progression in a representative population sample of adolescents: a prospective examination of vulnerability and risk factors.

UNLABELLED: AIMS/DESIGN: This study reports findings concerning risk factors for first, "repeated" and "regular" use of cannabis in respondents (N = 1228) who were aged 14-17 years at the outset (i.e. at "baseline") as part of a longitudinal prospective community study (EDSP). Risk factors were assessed at baseline or by separate interviews with the respondents' parents. Cumulative life-time cannabis use was the main outcome measure in this study--assessed by information from both the baseline and the follow-up investigation at an average of 19.7 months later. A cumulative logistic regression model was used to estimate associations. FINDINGS: Using seven of a total of 25 variables examined, the final model classified 72.1% of respondents correctly. Family history of substance use disorders, self-esteem and competence, unconditional commitment to not using drugs, immediate availability of drugs, peer group drug use and previous history of nicotine dependence and alcohol use disorders all contributed significantly to the final model, predicting the progression to cannabis use from "no use", to "one time only", "repeated use", and "regular use". CONCLUSION: In addition to well-documented risk factors such as peer group pressure, availability, low self-esteem and competence, findings suggest that family history and prior experiences with legal drugs play a significant role in the early development of cannabis consumption in teenagers.

Adolescent↗

PubMed1999

Changes in central venous pressure and pulmonary capillary wedge pressure do not indicate changes in right and left heart volume in patients undergoing coronary artery bypass surgery.

The value of pulmonary artery catheterization is a matter for discussion. Previous studies suggest that direct measurements of intravascular volume distribution and cardiac volume indices may be of greater relevance than central venous and pulmonary capillary wedge pressure. We therefore used a thermo-dye dilution technique for the quantification of central blood volume, right ventricular end-diastolic volume and left heart volume in patients undergoing coronary artery bypass surgery. Measurements were performed after the induction of anaesthesia as well as 1, 6 and 24 h after surgery. Central venous pressure was significantly increased at 1 and 6 h, whereas right ventricular end-diastolic volume was increased only at 6 h post-operatively. Pulmonary capillary wedge pressure showed a tendency to increase whereas left heart and central blood volume decreased significantly after surgery. The results of the present study suggest that changes in cardiac filling pressure do not indicate changes in indices of cardiac volume in patients after coronary bypass surgery.

Blood Volume↗