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K Sander-Jensen

Publications and source records attributed to K Sander-Jensen.

5 recordsLinked to original sources
PubMed1990

Does the decrease in heart rate prevent a detrimental decrease of the end-systolic volume during central hypovolemia in man?

Central hypovolemia occurring with epidural anesthesia was investigated by measurement of hemodynamic and endocrine variables in 10 patients. Responses fell into two categories. Four patients experienced a hypotensive bradycardic episode after seventeen +/- four minutes. In this group epidural anesthesia initially induced a tendency toward an increase in heart rate from 65 +/- 4 to 73 +/- 5 beats/min concomitantly with decreases in end-diastolic (172 +/- 22 to 138 +/- 16 mL), end-systolic (67 +/- 12 to 51 +/- 9 mL), and stroke (105 +/- 10 to 85 +/- 7 mL) volumes (radionuclide cardiography). A subsequent decrease in mean arterial pressure from 76 +/- 3 to 67 +/- 4 mmHg was associated with a decrease in venous return as reflected by the decrease in cardiac output from 6.1 +/- 0.4 to 4.7 +/- 0.7 L/min. In this situation when the venous return was critically reduced, the heart rate was 49 +/- 4 beats/min and no further reduction in end-diastolic and end-systolic volumes was observed. The observed endocrine changes were compatible with a response to central hypovolemia. In the other 6 patients the reaction to epidural anesthesia did not induce statistically significant changes in hemodynamic and endocrine variables. It is concluded (1) that the decrease in heart rate associated with central hypovolemia during epidural anesthesia seems to be elicited when the left ventricular end-systolic volume is decreased by about 25% and (2) that a further decrease in end-systolic volume during progressive central hypovolemia is avoided possibly as a direct consequence of the slowing of the heart.

Adult↗
PubMed1987

Central venous pressure--a physiological stimulus for secretion of atrial natriuretic peptide in humans?

A sensitive radio-immunoassay (RIA) for the measurement of human alpha-atrial natriuretic peptide (ANP) in extracted plasma was developed and used in a study of the possible effect of posture on the concentration of ANP in plasma. The least detectable quantity was less than 2 pg per tube equivalent to 5 pg ml-1 plasma. In the middle sensitivity range (approximately 50 pg per tube), the within-assay and between-assay coefficients of variation were 4.0 and 2.8%, respectively. The recovery of ANP added to plasma prior to extraction was 95-101%. High pressure liquid chromatography (HPLC) of plasma extracts revealed that endogenous ANP was eluted in the same fractions as synthetic ANP. In order to investigate the effect of posture on the concentration of ANP in plasma six healthy volunteers were exposed to five positions in the following sequence: supine, standing, sitting, supine and 10 degrees head-down tilt on a tilt-table. The concentration of ANP was lower in the standing and sitting position than in the supine and head-down tilted position. In another study six healthy volunteers were subjected to passive tilting on a tilt-table in order to evaluate the effect of tilting on blood pressure (BP), heart rate, central venous pressure (CVP) and the concentration of ANP in plasma. It was found that a fall in CVP was accompanied by a significant decrease in the concentration of ANP and that a rise in CVP was accompanied by a rapid increase in the concentration of ANP in plasma. The results are in agreement with the hypothesis that CVP is a physiological stimulus for the secretion of ANP.

Atrial Natriuretic Factor↗
PubMed1986

Vagal slowing of the heart during haemorrhage: observations from 20 consecutive hypotensive patients.

Heart rate and arterial blood pressure were monitored in 20 consecutive patients during resuscitation from haemorrhagic shock. The mean blood loss (2.3 (SEM 0.3) 1) corresponded to 36(4)% of their estimated mean blood volume. During shock the mean blood pressure was 81/55 (3/2) mm Hg and heart rate 73 (3) beats/min. Administration of blood and crystalloids resulted in immediate increases to 111/72 (2/2) mm Hg and 102 (3) beats/min followed by steady state values of 131/79 (6/3) mm Hg and 82 (2) beats/min. In three otherwise healthy patients plasma concentrations of the vagally regulated hormone pancreatic polypeptide rose from resting values of 64-77 pmol/l (272-327 pg/ml) to 198-280 pmol/l (842-1190 pg/ml). These findings suggest that reversible hypotensive hypovolaemic shock is characterised by a decrease in heart rate conceivably reflecting an increase in vagal tone.

Adult↗