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Biomedical subjects

S C Marsch

Publications and source records attributed to S C Marsch.

At least 19 recordsLinked to original sources
PubMed1995

The influence of preload on post-systolic shortening in ischaemic myocardium.

Post-systolic shortening is a wall motion abnormality defined as shortening of cardiac muscle after the end of ejection and usually regarded as a manifestation of ischaemia. This study was designed to determine whether changes in preload may alter the magnitude of ischaemia-induced post-systolic shortening. Eleven beagles were anaesthetized (halothane 0.8%) and instrumented for measurement of pressures, flows and dimensions in the apical subendocardium supplied by the left anterior descending coronary artery. Myocardial ischaemia was obtained by tightening a micrometer-controlled snare around the left anterior descending coronary artery. Post-systolic shortening, calculated as end-systolic length minus minimum length divided by end-systolic length, was measured at different levels of preload. Increasing the preload from 4 to 17 mmHg caused a significant reduction in post-systolic shortening (8.9% vs. 12.9%, P < 0.05, Student's paired t-test); post-systolic shortening was negatively correlated with coronary perfusion pressure (r = 0.35, P < 0.01) and positively correlated with systolic bulging. This study demonstrates that the amount of post-systolic shortening depends on the volume status, which therefore has to be taken into account in interpreting regional wall motion abnormalities, such as those detected by echocardiography.

Animals↗
PubMed1994

Post-ischemic diastolic dysfunction.

Though a sustained post-ischemic decrease in contractile function has been clearly established, post-ischemic diastolic function has not been thoroughly investigated. Accordingly, 11 anesthetized (isoflurane 1%) open-chest beagles were instrumented to measure left ventricular pressure and dimensions (circumferential length and wall thickness) in an apicoanterior area supplied by the left anterior descending coronary artery (LAD). Pressure-dimension relations were modified by stepwise infusion and withdrawal of 200 mL of the animals' own blood during baseline, 45 minutes partial occlusion of the LAD (systolic bulging), and 60 minutes after the onset of reperfusion. Stiffness constants were derived from the end-diastolic pressure-length and stress-strain relations, respectively. Myocardial ischemia was associated with significant (P < 0.05) alterations of the following parameters of diastolic function: (1) 47% increase in end-diastolic pressure; (2) 22% decrease in peak negative dP/dt; (3) 9% increase in the time constant of isovolumic relaxation (tau); (4) postcystolic contraction; (5) 6% increase in end-diastolic length and 10% decrease in end-diastolic thickness; (6) 12% increase in unstressed length (creep) and 13% decrease in unstressed thickness; (7) 51% increase in chamber stiffness and a 63% increase in myocardial stiffness; and (8) 40% decrease in the peak lengthening rate. After 60 minutes of reperfusion, only end-diastolic pressure and tau had returned to baseline values whereas systolic shortening fraction, postsystolic contraction, and end-diastolic and unstressed dimensions had only partially recovered. No recovery occurred in peak negative dP/dt, chamber stiffness, myocardial stiffness, and peak lengthening rate. Thus, both myocardial ischemia and reperfusion are associated with complex changes in global and regional left ventricular diastolic function.

Anesthesia, Inhalation↗
PubMed1994

Prolonged decrease in heart rate variability after elective hip arthroplasty.

The pattern of postoperative heart rate variability may provide insight into the response of the autonomic nervous system to anaesthesia and surgery. We have obtained spectral (fast Fourier transform) and non-spectral indices of heart rate variability from electrocardiographic recordings, sampled during continuous perioperative Holter monitoring in 15 otherwise healthy patients with an uncomplicated postoperative course, undergoing elective hip arthroplasty with either spinal or general anaesthesia. In both groups, total spectral energy (0.01-1 Hz), low-frequency spectral energy (0.01-0.15 Hz) and high-frequency spectral energy (0.15-0.40 Hz) decreased after surgery to 32% (95% confidence interval (CI) 10.5; P < 0.01), 29% (95% CI 12.5; P < 0.01) and 33% (95% CI 12.5; P < 0.01) of their preoperative values, respectively, and these indices remained suppressed for up to 5 days. Non-spectral indices decreased to a similar extent. These findings indicate a substantial and prolonged postoperative decrease in both parasympathetic and sympathetic influence on the sinus node.

Aged↗
PubMed1994

External ophthalmoplegia after total intravenous anaesthesia.

Eye-opening and eye movements were assessed in 110 awake and cooperative ASA class 1 and 2 patients after elective ENT surgery with total intravenous anaesthesia using propofol, fentanyl and atracurium. Following tracheal extubation and after regaining consciousness 21 patients showed a complete transient bilateral inability to open their eyes combined with a total gaze paresis, while another 30 patients showed an impairment of eye-opening and/or eye movements to a lesser extent. In all patients affected symmetrical recovery of both impaired eye-opening and eye movements occurred during the following 20 min. The occurrence of ophthalmological symptoms was not related to the duration of anaesthesia or the propofol infusion rate. Thus a complex ophthalmological phenomenon occurred after total intravenous anaesthesia in approximately 50% of awake and cooperative patients. The aetiology of this phenomenon and the implications for the understanding of the mechanisms of general anaesthesia remain to be determined.

Adult↗
PubMed1994

Teaching fibreoptic intubation in anaesthetised patients.

One hundred ASA grade 1 and 2 patients requiring orotracheal intubation for various general surgical procedures were randomly assigned to receive either expert rigid laryngoscopic or novice fibreoptic orotracheal intubation under total intravenous anaesthesia. Five anaesthesia residents in the 4th year, with no prior experience in fibreoptic laryngoscopy, participated in a fibreoptic training course, viewing two instructional videos and practising on the intubation manikin. Each resident intubated 20 patients in a randomised fashion either as an expert laryngoscopist or as a fibreoptic novice. The time (SEM) to achieve successful intubation was statistically different for fibreoptic and rigid intubation (77.2 (5.1) s vs 17.7 (1.6) s, p < 0.01). The time to achieve successful rigid laryngoscopic intubation remained constant over the ten intubations, whereas time required for fibreoptic intubation decreases significantly (p < 0.01). The learning objectives (fibreoptic intubation times in 60 s or less and with 90% or greater success rate on the first intubation attempt) were met by all residents. The haemodynamic profile was similar for fibreoptically intubated and conventionally intubated patients and there was no difference between the first two or the last two fibreoptic or rigid intubations. The study was designed to detect a difference of 10% in means (assuming alpha = 0.05 and beta < or = 0.2). The incidence of postoperative sore throat, dysphagia or hoarseness was similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Haemodynamic response to fibreoptic versus laryngoscopic nasotracheal intubation under total intravenous anaesthesia.

Thirty ASA physical status I and II patients scheduled for elective maxillofacial surgery received total intravenous anaesthesia with propofol, fentanyl and atracurium and were randomly allocated to undergo either fibreoptic or orthodox nasotracheal intubation. Haemodynamic responses to intubation were similar for both techniques. The peak values for heart rate and blood pressure after induction were not significantly different from the baseline values for each group. There was no significant difference in the time required to complete intubation. SpO2 and end-tidal CO2 were similar for both techniques.

Adult↗
PubMed1993

Graded myocardial ischemia is associated with a decrease in diastolic distensibility of the remote nonischemic myocardium in the anesthetized dog.

OBJECTIVES: This study was designed to investigate the changes in regional distensibility of the ischemic segment and of a remote nonischemic segment brought about by graded myocardial ischemia. BACKGROUND: Ventricular distensibility is a major determinant of left ventricular end-diastolic pressure. The effects of graded myocardial ischemia on the regional distensibility of the ischemic area have not been studied. Moreover, there are few data on the effects of myocardial ischemia on the regional distensibility of the nonischemic myocardium. METHODS: Nine anesthetized open chest mongrel dogs were fitted with instruments to measure left ventricular pressure and circumferential length (sonomicrometry) in the ischemic segment and in a nonischemic segment. The pressure-length relation was modified by stepwise infusion and withdrawal of 200 ml of each dog's own blood over 30 min in five consecutive stages of regional ischemia. Unstressed dimensions were obtained by repeated inferior vena cava occlusions. In both segments, regional distensibility was assessed at end-diastole by means of the constants of the pressure-length (chamber stiffness), the pressure-strain and the force-strain (myocardial stiffness) relations. RESULTS: In the ischemic segment, partial and complete coronary occlusions were associated with a twofold increase in the chamber stiffness constant, the pressure-strain constant and the myocardial stiffness constant, whereas in the nonischemic segment the chamber stiffness constant, the pressure-strain constant and the myocardial stiffness constant increased by 50%. CONCLUSIONS: Regional myocardial ischemia is associated with a decrease in distensibility of both the ischemic and the remote nonischemic myocardium.

Analysis of Variance↗
PubMed1993

Vasovagal heart block following cataract surgery under local anesthesia.

Hemodynamic alterations during eye surgery usually consist of sinus bradycardia and hypotension provoked by the oculocardiac reflex. We report a case in which severe sinus bradycardia occurring immediately after the end of surgery was complicated by second-degree atrioventricular block, hypotension, and symptomatic myocardial ischemia.

Aged↗
PubMed1993

Is normal saline an acceptable alternative to silicone for lubricating fibrescopes?

This article describes a model designed to measure the forces acting on a fibrescope when it is pushed through an endotracheal tube. Lubrication with either silicone or normal saline leads to a reduction in friction forces. Fibrescopes lubricated with normal saline require a larger force to be advanced through endotracheal tubes when compared to silicone; however, the difference is clinically unimportant and is outweighed by the advantageous properties of normal saline. A theoretical model is presented which is in close agreement with experimentally derived data.

Butanes↗
PubMed1992

Perioperative myocardial ischemia in patients undergoing elective hip arthroplasty during lumbar regional anesthesia.

Perioperative myocardial ischemia predicts unfavorable outcomes and occurs in as many as 41% of patients with coronary artery disease or cardiac risk factors undergoing noncardiac surgery. To determine the prevalence of myocardial ischemia, we studied 52 consecutive unselected patients undergoing elective hip arthroplasty during lumbar regional anesthesia. Patients were continuously monitored for 6 days using a three-channel Holter monitor. Ninety-nine episodes of myocardial ischemia occurred in 16 patients (31%), six of whom were considered preoperatively to be at low risk for coronary artery disease. Forty-four percent of the ischemic episodes were preceded or accompanied by a heart rate greater than or equal to 100/min and 56% by a heart rate greater than or equal to 90 beats/min. Ninety-six percent of the ischemic episodes were clinically silent, and 82% were not related to patient care events. Thirteen episodes of myocardial ischemia occurred preoperatively, 1 intraoperatively, and 85 postoperatively. The incidence of postoperative ischemic episodes showed a circadian variation: 44% occurred between 6 AM and noon, 33% between noon and 6 PM, 17% between 6 PM and midnight, and 6% between midnight and 6 AM. Six adverse cardiac events occurred during hospitalization (three of the six among patients with perioperative ischemia) and an additional four events during a follow-up period of 12 months (all four events occurred among patients with perioperative ischemia). Patients with perioperative myocardial ischemia had a relative risk of 2.6 (95% confidence interval 1.3-5.2) to develop an adverse cardiac event postoperatively.

Aged↗
PubMed1992

Failure of continuous three-channel Holter monitoring to detect acute peri-operative myocardial infarction.

Continuous peri-operative three-channel Holter monitoring in a 70-year-old patient undergoing elective hip arthroplasty failed to show onset and progression of a lethal postoperative myocardial infarction, which was clearly visible in a 12-lead electrocardiogram. The modified bipolar leads used for Holter monitoring differed from the corresponding leads of the 12-lead electrocardiogram. The limitations of Holter monitoring applied to clinical management and research are highlighted.

Aged↗
PubMed1992

Cardiovascular effects of fibreoptic oral intubation. A comparison of a total intravenous and a balanced volatile technique.

The cardiovascular response to fiberoptic oral intubation under total intravenous anaesthesia with propofol or a balanced volatile technique with thiopentone/enflurane was compared in 50 patients of physical status ASA 1 and 2 who were scheduled for elective ear, nose and throat surgery. Patients were randomly assigned to receive propofol or enflurane. There was no significant difference between the two anaesthetic techniques in haemodynamic profile either before, during or after fibreoptic intubation (the study design was adequate to detect a 20% difference with > 90% statistical power), in incidence of postoperative sore throat or in time taken for intubation. In no patient did the oxygen saturation decrease to below 95% or the CO2 tension exceed 5.8 kPa.

Adult↗
PubMed1992

Art and anaesthesia.

Explore the source record for details and available documents.

Anesthesia, Intravenous↗
PubMed1992

Dreaming and anaesthesia: total i.v. anaesthesia with propofol versus balanced volatile anaesthesia with enflurane.

Sixty consecutive ASA Grades I and II patients scheduled for elective ear, nose and throat surgery were randomly assigned to receive either total i.v. anaesthesia with propofol ('propofol group') or 'balanced technique' with thiopentone induction followed by N2O and enflurane. Patients were asked whether they had experienced dreams immediately after extubation when verbal communication was established, in the recovery room and in the ward on the evening of the day of surgery. Thirteen patients in the propofol group (43%) and three patients in the enflurane group (10%) reported dreaming (P less than 0.05) when asked as soon as verbal communication was established. In the recovery room and in the ward only three patients of the propofol group (10%) and one patient in the enflurane group (3%) remembered that they had been dreaming (NS). To avoid underestimating the frequency of peri-operative dreaming, post-operative interviews should take place as soon as possible after conversing is possible.

Adult↗
PubMed1991

Comparison of orthodox with fibreoptic orotracheal intubation under total i.v. anaesthesia.

Fibreoptic orotracheal intubation was compared with orthodox laryngoscopy and tracheal intubation using a total i.v. technique with propofol in 60 ASA I and II patients. There was no significant difference between the two techniques in haemodynamic profile (before, during and following the intubation procedure) and incidence of postoperative sore throat. Minimal oxygen saturation was 96% during the study; maximal end-tidal PCO2 after intubation was 5.4 kPa. Intubation time was faster (P less than 0.01) in the orthodox group (30.7 (SEM 2.3) s) than in the fibreoptic group (52.7 (4.8) s).

Anesthesia, Intravenous↗
PubMed1990

[Adenocarcinoma of the small intestine in celiac disease. Case report and literature review].

We describe three patients with celiac disease complicated by adenocarcinoma of the small intestine, and summarize the 36 cases of this association that have been reported. Retrospectively we found an increased risk (relative risk 25-250) of developing adenocarcinoma of the small intestine in patients with celiac disease in the region of Winterthur (north-east Switzerland). We therefore suggest that celiac disease be considered a premalignant condition not only for malignant lymphoma and gastrointestinal tumors, but also for adenocarcinoma of the small intestine. Synchronous or metachronous development of carcinoma in one of our patients and in two cases reported in the literature offer further evidence that celiac disease is a premalignant condition for adenocarcinoma of the small bowel. In several patients celiac disease was diagnosed only after diagnosis of the carcinoma. With regard to asymptomatic or subclinical celiac disease, it seems justifiable to search for possible underlying celiac disease in all patients with established diagnosis of adenocarcinoma of the small intestine.

Adenocarcinoma↗