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N Roewer

Publications and source records attributed to N Roewer.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Are morphologic changes in skeletal muscles of patients with malignant hyperthermia diagnostically useful?].

Malignant Hyperthermia (MH) represents a functional myopathy triggered by volatile anesthetics and depolarizing muscle relaxants, and leading to metabolic disturbances of intracellular Calcium homeostasis. Central-Core-like-structures (CCLS) were recently described as central defects in enzyme-histochemical stains and well correlated to the autosomal-dominant MH-predisposition. We studied the correlation of a MH-predisposition with specific myopathological signs. Skeletal muscles of suspected MH-individuals were histochemically stained by SDH-, NADH-, COX-, Gomori-Trichrome-, ATPase-, Acid Phosphatase-, Oil-red O- und PAS-stain und evaluated without knowing MH-diagnosis by the in-vitro-contracture test. Out of 118 patients (30% MHS ["susceptible"], 63% MHN [normal], 7% MHE ["equivocal"]) 19% revealed pathological findings corresponding to CCLS. 45% of these findings were associated with MHS/MHE. With HE-staining internal nuclei were not specific, but increased with the probability of MHS/MHE from 24% to 80%. Central Cores were correlated in 100% with MHS/MHE (4 out of 118 patients). CCLS were found with about similar frequency in skeletal muscle of MHS/MHE and MHN individuals. Internal nuclei were, however, not specifically, associated with MHS. In contrast, Central Cores correlated significantly with MHS/MHE diagnosis. In conclusion, histopathological findings in skeletal muscle seem to be a reliable marker for MH-predisposition only with Central Cores.

Adolescent↗
PubMed1999

Transnasal transesophageal echocardiography: a modified application mode for cardiac examination in ventilated patients.

UNLABELLED: In 42 endotracheally intubated patients, we examined the utility of a miniaturized monoplane probe for transnasal transesophageal echocardiography (TEE). Transnasal TEE was prospectively evaluated in 26 deeply and 16 mildly sedated patients receiving topical anesthesia with lidocaine jelly 2%. The patients with deep sedation were additionally examined with transoral monoplane and multiplane TEE. Transnasal esophageal insertion of the TEE probe was successfully performed in 90% of patients. Endotracheal malpositioning was corrected in two patients. Nasal bleeding required treatment in another patient. Topical anesthesia was adequate in 82% of mildly sedated patients. Left ventricular short- and four-chamber long-axis views of good quality were obtained with transnasal (transoral) monoplane TEE in 76% (81%) and 92% (96%) of patients (differences not significant). Compared with conventional multiplane TEE, transnasal monoplane TEE missed diagnoses in 19% of patients. The relative error (mean +/- SEM) of quantification with transnasal TEE was <9% +/- 2% for ventricular diameters and <7% +/- 2% for cross-sectional area measurements, with a bias of 0.5 +/- 3.8 cm2 and 0.1 +/- 2.4 cm2 (mean +/- 2 SD) for left ventricular end-diastolic and end-systolic short-axis areas. The relative error in measuring intracardiac flow velocities was >40%, but systolic to diastolic peak velocity ratios at the valvular site were determined with an error <4% +/- 3%. Transnasal monoplane TEE can be performed even in mildly sedated patients with an endotracheal tube without further need for analgesia or sedation. The technique is as useful as conventional transoral TEE to image standard tomographic planes for quantification, but it is less suited for comprehensive echocardiographic diagnosing. IMPLICATIONS: Transnasal insertion of a miniaturized monoplane transesophageal echocardiography (TEE) probe was studied in endotracheally intubated patients. Nasal passage was well tolerated even by patients with only mild sedation. Imaging quality was similar to conventional transoral monoplane TEE with larger transducers, but technical restraints cause a deficit in complete cardiac diagnosing obtained with multiplane TEE.

Anatomy, Cross-Sectional↗
PubMed1999

A simplified risk score for predicting postoperative nausea and vomiting: conclusions from cross-validations between two centers.

BACKGROUND: Recently, two centers have independently developed a risk score for predicting postoperative nausea and vomiting (PONV). This study investigated (1) whether risk scores are valid across centers and (2) whether risk scores based on logistic regression coefficients can be simplified without loss of discriminating power. METHODS: Adult patients from two centers (Oulu, Finland: n = 520, and Wuerzburg, Germany: n = 2202) received inhalational anesthesia (without antiemetic prophylaxis) for various types of surgery. PONV was defined as nausea or vomiting within 24 h of surgery. Risk scores to estimate the probability of PONV were obtained by fitting logistic regression models. Simplified risk scores were constructed based on the number of risk factors that were found significant in the logistic regression analyses. Original and simplified scores were cross-validated. A combined data set was created to estimate a potential center effect and to construct a final risk score. The discriminating power of each score was assessed using the area under the receiver operating characteristic curves. RESULTS: Risk scores derived from one center were able to predict PONV from the other center (area under the curve = 0.65-0.75). Simplification did not essentially weaken the discriminating power (area under the curve = 0.63-0.73). No center effect could be detected in a combined data set (odds ratio = 1.06, 95% confidence interval = 0.71-1.59). The final score consisted of four predictors: female gender, history of motion sickness (MS) or PONV, nonsmoking, and the use of postoperative opioids. If none, one, two, three, or four of these risk factors were present, the incidences of PONV were 10%, 21%, 39%, 61% and 79%. CONCLUSIONS: The risk scores derived from one center proved valid in the other and could be simplified without significant loss of discriminating power. Therefore, it appears that this risk score has broad applicability in predicting PONV in adult patients undergoing inhalational anesthesia for various types of surgery. For patients with at least two out of these four identified predictors a prophylactic antiemetic strategy should be considered.

Adult↗
PubMed1998

The volatile anesthetic enflurane activates capacitative Ca2+ channels in rat glioma C6 cells.

(1) The volatile anaesthetics halothane and enflurane released Ca2+ from thapsigargin sensitive stores in rat glioma C6 cells, but only enflurane induced a significant Ca2+ influx. (2) The reason for this can be explained by a different inhibitory effect of the anesthetics on the capacitative Ca2+ influx. (3) Halothane inhibited the capacitative Ca2+ influx with an IC50 of 1.9 vol.%, whereas enflurane only marginally affected the ion flux through the channel.

Anesthetics, Inhalation↗
PubMed1998

[Early clinical results with transnasal esophageal echocardiography].

UNLABELLED: Currently undergoing a clinical trial a new miniaturized monoplane ultrasound probe potentially enhances the practicability of perioperative transesophageal echocardiography (TEE) without loss of echocardiographic quality. METHODS: In the present prospective study, the nasally inserted miniaturized TEE probe was tested in 12 ventilated patients and compared with a conventional TEE probe. Echocardiographic quality was tested by two independent investigators by analyzing the percentage of the endocardium contour detection (< 50%, 50-75%, 75-100%) in the left ventricular short- and long-axis views. RESULTS: In 11 patients, more than 50% of endocardium were visualized continuously with both probes. Although the nasal TEE probe was inferior to conventional TEE in detecting lateral endocardium, automated endocardium detection compared well with both methods. Inter- and intraobserver variability in manual measurements of the left ventricular cross-sectional area was below 5% on average and differed non-significantly with regard to the method. In 2 patients, continuous monitoring was aggravated by repeated loss of contact between the miniaturized TEE probe and mucosa. CONCLUSIONS: In comparison with conventional TEE, the miniaturized TEE probe provides practicability advantages without significant loss of information for cardiovascular monitoring.

Adult↗
PubMed1998

[Postoperative vomiting. A score for prediction of vomiting risk following inhalation anesthesia].

UNLABELLED: Despite numerous factors are thought to affect postoperative vomiting (PV) recent studies demonstrated that the risk of PV can be predicted by considering just the most important ones. Therefore, the aim of this study was to present the clinically most relevant factors, a risk score based upon those factors and its clinical applicability for other types of surgery. METHODS: In a prospective study 2220 adult inpatients scheduled for elective surgery were monitored for PV after inhalational anaesthesia over 24 hours. None of the patients received prophylactic antiemetic treatment. Multivariate analyses were performed with data of patients who underwent otolaryngological procedures to identify the major risk factors and to derive a risk score. The applicability of the score in surgical and ophthalmological procedures was tested by linear regression analysis of expected and observed incidences. RESULTS: In the multivariate model, clinically most important risk factors for PV were female gender, young age, a positive history of postoperative nausea and vomiting or motion sickness, non-smoking and a long duration of anaesthesia, whereas the relative impact of the "type of operation itself" was small. Expected and observed incidences in patients undergoing other types of surgery were strongly correlated (R2 = 0.99, P < 0.001). CONCLUSION: The risk for PV after inhalational anaesthesia in adults can be predicted using a score which is based on individual risk factors and the duration of anaesthesia only.

Adolescent↗
PubMed1998

[Problems with infusion of vasoactive drugs].

An infusion system that is insufficiently equipped with an alarm device in case the syringe pumps are obstructed, may gravely endanger patient safety. In a patient with septic shock, an obstruction of the infusion system led to periodic application of norepinephrine boli. Sudden haemodynamic disturbances in critically ill patients should be evaluated for pathological causes as well as for technical failure in the infusion system. A sensitive alarming system of syringe pumps may help to eliminate inappropriate drug delivery. For safe infusion of vasoactive drugs the following conditions are highly recommended: a singular syringe pump, a high volume delivery at a low drug concentration, a pressure-controlled infusion device and a short and pressure-resistant infusion system.

Blood Pressure↗
PubMed1998

A risk score to predict the probability of postoperative vomiting in adults.

BACKGROUND: The aim of this study was to identify factors most relevant for postoperative vomiting (PV) and to develop a risk score to predict the probability of PV. METHODS: Adult inpatients scheduled for elective ear, nose and throat (ENT) surgery under general anaesthesia were offered to participate in a prospective study for PV over 24 h. No prophylactic antiemetics were used. The data of 1137 patients were randomized and split into an evaluation set (n=553) and a validation set (n=584). The evaluation set was subjected to logistic regression analysis to quantify the relative impact of anaesthetic, surgical and individual factors and to develop a risk score. The score was then tested by applying it to the validation set. The area under a receiver operation characteristic (ROC) curve was calculated and the predicted and actual incidences of patients were correlated. RESULTS: In the evaluation set, patient-related factors (female gender, young age, non-smoking, history of PV or motion sickness) and a high duration of anaesthesia were independent risk factors for PV. The probability of PV could be estimated from the equation: PV=1/(1+exp(-z)) where z=1.28 (gender)-0.029 (age)-0.74 x (smoking)+0.63 x (history of PV or motion sickness)+0.26 x (duration)-0.92. In the validation set this score achieved an area under the ROC-curve of 0.78 and the actual incidence correlated strongly with the predicted risks (R2=0.93, P<0.001). CONCLUSION: The data suggest that the probability of PV following ENT surgery under inhalational anaesthesia with low-dose opioids can be predicted by a score mainly based upon patient-related risk factors.

Adult↗
PubMed1998

The discriminating power of a risk score for postoperative vomiting in adults undergoing various types of surgery.

BACKGROUND: Recently, we have demonstrated that the probability of postoperative vomiting (PV) following ENT surgery with inhalational anaesthetics can be predicted using a risk score. This score is based on gender, age, smoking status, history of motion sickness or postoperative nausea and vomiting and the duration of anaesthesia. Therefore, it is of interest whether this score is also accurate in predicting PV in patients undergoing different types of surgery. METHODS: Inpatients scheduled for bone, vascular, general or eye surgery were included in a prospective survey for PV over 24 h. Data of 1091 patients were analyzed, of which 542 were used for the validation of the previously constructed risk score (Score I). The data of the remaining 549 patients were used to evaluate the risk factors that contribute to PV in this setting and to develop a new score (Score II). The discriminating power of both scores to predict PV was tested in the validation set (n=542) and compared by calculating the area under the receiver operating characteristic (ROC) curves. RESULTS: The area under the ROC curve of Score I was 0.77 (SD 0.024). Risk factors for PV in the evaluation set were female gender, young age, history of motion sickness or postoperative nausea and vomiting and the type of surgery. The area under the curve of Score II was 0.75 (SD 0.026) and was not significantly different from Score I (P=0.57). CONCLUSION: Score I was accurate in predicting PV in patients after most types of surgery with volatile anaesthetics, which suggests that this score might be useful for other centres as well.

Adult↗
PubMed1997

Relation of echocardiographic preload indices to stroke volume in critically ill patients with normal and low cardiac index.

OBJECTIVE: To examine the usefulness of preload indices obtained by transoesophageal echocardiography (TOE) for estimating stroke volume at various levels of cardiac index. DESIGN: Prospective clinical study. SETTING: Intensive care unit with surgical patients. PATIENTS: 16 ventilated patients monitored via Swan-Ganz catheterization and TOE. INTERVENTIONS: Echocardiographic images of left ventricular cross-sectional short-axis areas were analysed for the preload indices end-diastolic area (EDA), stroke area and end-diastolic wall stress. The relation between these indices and stroke volume, calculated from thermodilution cardiac output, was analysed in all patients and in nine patient groups discriminated by various ranges in heart rate (< or = 70 to > 110 beats/min), pulmonary artery occlusion pressure (< or = 8 to > 12 mmHg) and cardiac index (< or = 3.0 to > 4.2 l/min per m2). MEASUREMENTS AND RESULTS: Overall stroke volume (n = 155) correlated significantly (p < 0.0001) with EDA (r = 0.89) and stroke area (r = 0.80). The correlation with end-diastolic wall stress was non-significant (r = 0.51). Linearity in the relation between stroke volume and EDA or stroke area was independent of variations in heart rate and pulmonary artery occlusion pressure. Stroke volume correlated well with EDA and stroke area, when cardiac index was normal or high, but the relation slightly deteriorated (r = 0.63 to < or = 0.72) when the cardiac index was low. Changes in EDA and stroke area by more than 1, 2 or 3 cm2 were weak predictors for changes in stroke volume greater than 20%. CONCLUSIONS: Stability of the relation between echocardiographic preload indices and stroke volume emphasize the potential of TOE for continuous preload monitoring in the critically ill.

Cardiac Output↗