scholarly journals Maternal hemodynamic effect of prophylactic glycopyrrolate after spinal anaesthesia for elective caesarean section

2021 ◽  
Vol 8 (1) ◽  
pp. 44-50
Author(s):  
Roshan Piya ◽  
Anil Shrestha ◽  
Manisha Pradhan ◽  
Shirish Amatya ◽  
Niroj Hirachan ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Caesarean Section ◽  
Arterial Pressure ◽  
Spinal Anesthesia ◽  
Elective Caesarean Section ◽  
Hemodynamic Effect ◽  
Group I ◽  
Group Ii

Introduction: Hypotension and bradycardia are the most common complications during spinal anesthesia. Bradycardia decreases cardiac output, resulting in hypotension and even cardiac arrest. Glycopyrronium, an anticholinergic drug increases heart rate and prevents bradycardia during spinal anesthesia by blocking the effects of acetylcholine on the sinoatrial node. The study aims to measure the maternal hemodynamic effect of glycopyrrolate after spinal anesthesia for elective caesarean section. Method: An intervention, comparative study was conducted in Patan Hospital after approval from Ethical Committee. Eighty-two pregnant women scheduled for elective caesarean section were randomly assigned in two groups by sealed envelope method; Group I received glycopyrrolate 0.2mg intravenous,  Group II did not receive glycopyrrolate. The patient’s heart rate, blood pressure, mean arterial pressure, a total dose of ephedrine, the occurrence of nausea, vomiting, and dry mouth were recorded. Independent-T test, chi-square test were used for statistical analysis. Result: Among 82 elective caesarean sections, 41 in each group, Group II (non-glycopyrrolate) reported increased heart rate compared to Group I (glycopyrrolate), but was statistically not significant. The highest recorded diastolic blood pressure was more in Group I compared to Group II and was statistically significant. The highest recorded Mean Arterial Pressure was high in the glycopyrrolate group and was statistically significant. The total dose of ephedrine was lower in the statistically significant glycopyrrolate group. The incidence of dry mouth was more in the glycopyrrolate group and the difference was statistically significant. Conclusion: Glycopyrrolate reduces the incidence of hypotension but not bradycardia and decreases the need for vasopressor.

scholarly journals Perbedaan Respon Hemodinamik dengan Penambahan Blok Scalp Levobupivakain pada Operasi Kraniotomi

2020 ◽  
Vol 9 (1) ◽  
pp. 8-15
Author(s):  
Arya Justisia Sani ◽  
Ardhana Tri Arianto ◽  
Muhammad Husni Thamrin
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Hemodynamic Response ◽  
Anesthesia Induction ◽  
Group I ◽  
Significant Difference ◽  
Scalp Block ◽  
One Way Anova

Latar Belakang dan Tujuan: Peningkatan respon hemodinamik yang disebabkan oleh nyeri dapat menyebabkan peningkatan aliran darah otak dan tekanan intrakranial. Blok scalp pada kraniotomi menumpulkan respon hemodinamik karena rangsangan nyeri serta mengurangi penambahan analgesi lain. Penelitian ini bertujuan untuk mengetahui efektifitas blok scalp sebagai analgetik pada kraniotomi.Subjek dan Metode: Penelitian ini menggunakan uji klinik acak tersamar ganda pada 36 pasien dengan status fisik ASA 1–3 dilakukan operasi kraniotomi eksisi dan memenuhi kriteria inklusi. Sampel dibagi menjadi kelompok I (dengan blok scalp) dan kelompok II (tanpa blok scalp). Blok dilakukan sesaat setelah induksi anestesi. Digunakan levobupivakain 0,375% sebanyak 3 ml tiap insersi, pada masing-masing saraf. Tekanan darah, tekanan arteri rata-rata, detak jantung sebelum intubasi dan setelah intubasi, pemasangan pin, insisi kulit dan insisi duramater serta total kebutuhan fentanyl tambahan dicatat. Data yang diperoleh dianalisis dengan program komputer SPSS versi 17 lalu diuji menggunakan uji Kruskal-Wallis atau One-way ANOVA. Batas kemaknaan yang diambil adalah p < 0,05.Hasil: Selama kraniotomi, detak jantung, tekanan darah, tekanan arteri rata-rata secara signifikan lebih tinggi pada pasien tanpa blok scalp terutama pada saat pemasangan pin. Hasil uji statistik menunjukkan perbedaan signifikan, penambahan fentanyl pada pasien dengan blok scalp lebih sedikit dibandingkan tanpa blok scalp, p=0,000 (p<0,05).Simpulan: Blok scalp levobupivakain efektif dalam menurunkan respon hemodinamik terutama pada saat pemasangan pin. Pasien kraniotomi dengan blok scalp membutuhkan penambahan fentanyl lebih sedikit. Differences on Hemodynamic Response with Levobupivacaine Scalp Block in Craniotomy SurgeryAbstractBackground and Objective: Increased hemodynamic response caused by pain can lead to increased cerebral blood flow and intracranial pressure. Scalp block in craniotomy blunts hemodynamic response due to pain and reduce other analgesics addition. This study aims to determine effectiveness of scalp blocks as analgesic in craniotomy.Subject and Method: This study used a double-blind randomized clinical trial in 36 patients with physical status ASA 1-3 who underwent craniotomy and met inclusion criteria. Samples were divided into group I (with scalp block) and group II (without scalp block). Scalp Block was performed right after anesthesia induction. Using levobupivacaine 0.375% 3 ml for each insertion. Blood pressure, mean arterial pressure, heart rate before and after intubation, during pin placement, skin incision and duramater incision and total need for additional fentanyl were recorded. SPSS version 17 was used and data were analysed using Kruskal-Wallis or One-way ANOVA. Statistical significance was accepted at p < 0.05.Result: During craniotomy, heart rate, blood pressure, mean arterial pressure were significantly higher in patients without scalp block especially during pin placement. Statistical test showed significant difference, additional fentanyl in patients with scalp blocks was lesser, p = 0.000 (p <0.05). Conclusion: Levobupivacaine scalp block was effective to blunt hemodynamic response especially during pin placement. Scalp block also decreased additional fentanyl in craniotomy.

Renal Denervation Prevents Sodium Retention and Hypertension in Salt-Sensitive Rabbits with Genetic Baroreflex Impairment

1996 ◽  
Vol 90 (4) ◽  
pp. 287-293 ◽  
Author(s):  
Marta Weinstock ◽  
Elena Gorodetsky ◽  
Ronald Kalman
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Renin Activity ◽  
Renal Denervation ◽  
Plasma Renin ◽  
High Salt ◽  
Renin Activity ◽  
Group I ◽  
Group Ii

1. Rabbits with a genetic impairment in baroreflex control of heart rate become hypertensive on a high salt diet. The present study determined the effect of bilateral renal denervation on blood pressure and sodium balance after salt loading (four times normal intake; 28–36 mEq NaCl/day) in normotensive rabbits with high (Group I) and low (Group II) baroreflex sensitivity, respectively. 2. Eight rabbits in each group were denervated or sham-denervated 1 week before commencement of the high salt diet. Before operation, the two groups differed only in the gain of their cardiac baroreflex (Group I, −6.4 ± 0.4 beats min−1 mmHg−1; Group II, −3.2 ± 0.15 beats min−1 mmHg−1). 3. In Group I sham-denervated rabbits, mean arterial pressure remained unchanged, and plasma renin activity and heart rate fell significantly in response to the high salt. In Group II sham-denervated rabbits, mean arterial pressure increased by 10.6 ± 1.2 mmHg, and heart rate and plasma renin activity remained unchanged. Their cumulative Na+ retention and weight gain was more than twice that of Group I sham-denervated rabbits. 4. Renal denervation decreased plasma renin activity in both groups to <1 pmol Ang I h−1 ml−1, lowered cumulative Na+ retention from 102 ± 4 to 35 ± 5 mEq (P<0.01) and completely prevented the increase in mean arterial pressure in response to high salt in Group II. 5. The results suggest that Group II rabbits retain salt and fluid in response to their diet because of an abnormality in their control of renal nerve activity, possibly via vagal afferents. This results in blood pressure elevation because of an inability to lower peripheral resistance and heart rate in response to the increase in cardiac output. 6. Since they display several of the characteristics of salt-sensitive hypertensive humans, i.e. salt retention, normal plasma renin activity, but abnormal regulation of plasma renin activity and blood flow in response to salt loading, Group II are an appropriate model of human salt-induced hypertension.

scholarly journals Comparative Evaluation of Topical Lignocaine Versus Intravenous Lignocaine for Laryngeal Mask Airway Insertion in Wardha, Maharashtra

2021 ◽  
Vol 10 (28) ◽  
pp. 2078-2082
Author(s):  
Swathi Reddy G. ◽  
Karuna Taksande
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Laryngeal Mask Airway ◽  
Arterial Pressure ◽  
Comparative Evaluation ◽  
Laryngeal Mask ◽  
Laryngeal Mask Airway Insertion ◽  
Hemodynamic Parameters ◽  
Group I

BACKGROUND The purpose of present study was to compare and evaluate both topical lignocaine and intravenous lignocaine for laryngeal mask airway (LMA) insertion prior to propofol. Main objective was to study the conditions for LMA insertion with respect to gagging, coughing, Laryngospasm and No. of attempts for LMA insertion and also study the hemodynamic parameters in both the groups (Heart rate, SBP,DBP, MAP, SpO2) METHODS This study included 60 patients of 30 in each group, ASA I & II day care surgeries were performed in our hospital between 2019 and 2021. Patients were randomized into two groups. Group I received intravenous lignocaine 1.5 mg / kg over 30 seconds and group II received topical lignocaine 40 mg. Conditions of LMA insertion, gagging, laryngospasm, coughing were noted at the time of insertion, ECG, NIBP, SPO2 and ETCO2 were recorded according to scheduled times. RESULTS In conditions of LMA insertion, difference between both the groups was found to be significant, P < 0.05 in groups with first minute rise in heart rate, fall in Systolic blood pressure, diastolic blood pressure, mean arterial pressure was significant. At two minutes and three minutes after the LMA insertion, HR, SBP, DBP, MAP all these parameters changed slightly but these changes were statistically not significant. CONCLUSIONS Prior to Propofol induction, compared to intravenous lignocaine, topical lignocaine 10 % aerosol provided excellent conditions for the insertion of LMA without the use of neuromuscular blockers. KEY WORDS IV Lignocaine, Topical Lignocaine, LMA

scholarly journals Hemodynamic Effects of Intrathecal Magnesium Sulphate as an Adjuvant for Spinal Anesthesia in Pre-Eclamptic Patients

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
R H Elkabarity ◽  
R M M Ali ◽  
J N Naseef ◽  
M M F Hanna
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Caesarean Section ◽  
Systolic Blood Pressure ◽  
Magnesium Sulfate ◽  
Spinal Anesthesia ◽  
Magnesium Sulphate ◽  
Hemodynamic Effect ◽  
Motor Blockade ◽  
Hemodynamic Effects

Abstract Background pre-eclampsia is defined as a disorder that occurs in pregnancy after twenty weeks of gestation which manifests as hypertension and proteinuria with at least one maternal organ dysfunction involvement with an incidence of 5-10% of all pregnancies. Aim of the Work our study will examine the hemodynamic effects of adding two different doses of magnesium sulphate to bupivacaine in patients with severe preeclampsia undergoing caesarean section using spinal anesthesia. Patients and Methods: type of Study Prospective comparative study; it was done after approval of the Research Ethics Committee of Anesthesia, Intensive Care and Pain Management Department, Ain Shams University. Study Setting Ain Shams University Hospitals, Cairo, Egypt. Study Period 3 months. Study Population Pregnant females with severe preeclampsia undergoing caesarian section. Results results of this study indicated that the addition of magnesium sulfate at a dose of 100mg compared to the dose of 50 mg to bupivacaine showed that increasing the dose of magnesium sulfate had no significant hemodynamic effect (systolic blood pressure, diastolic blood pressure and heart rate) on severe preeclamptic patients undergoing caesarean section. But the addition of 100 mg magnesium sulfate lead to a significant delay in the onset of both sensory and motor blockade, and prolonged the duration of sensory and motor blockade compared to the addition of 50mg magnesium sulphate. Also there is no significant difference between the addition of 50 &100mg on shivering, nausea and vomiting, sedation, postoperative pain score (at 2,4 and 8 hours) and APGAR score (at 1 and 5 min). Conclusion the addition of magnesium sulfate at a dose of 100mg compared to the dose of 50 mg to bupivacaine in our study, showed that increasing the dose of magnesium sulfate had no significant hemodynamic effect (systolic blood pressure, diastolic blood pressure and heart rate) on severe preeclamptic patients undergoing caesarean section.

scholarly journals Effectivity of 5% Dextrose-Diluted and Ringer Lactate-Diluted Propofol to Reduce Intravenous Injection Pain in Pediatric Patient

2020 ◽  
Vol 2 (1) ◽  
pp. 33
Author(s):  
Dian Raseka Parna ◽  
Arie Utariani ◽  
Elizeus Hanindito
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Intravenous Injection ◽  
Pediatric Patients ◽  
Injection Pain ◽  
Control Group ◽  
Ringer Lactate ◽  
Group I

Introduction: Propofol has been known as one out of many inductive drugs which, can cause pain during intravenous injection. There has been a high prevalence of injection pain in pediatric patients. The mechanism of injection pain has not been known. Some therapeutic methods have been tested to reduce the pain, with several success rates. Objective: To compare the effectivity of 5% dextrose-diluted propofol and ringer lactate-diluted propofol, with dilution comparison of 1:1, in their role to reduce intravenous injection pain in pediatric patients, from age 2-15 years old during elective surgery in the Integrated Surgical Building Center of Dr. Soetomo General Hospital Surabaya. Method and Material: Forty-five patients PS ASA I-II, which fulfill inclusion criteria, were induced with general anesthesia. Patients had been selected randomly into three groups. Group I (control group) were injected with propofol without dilution. Group II was injected with propofol with a dilution of 5% dextrose, into 5 mg/ml liquid. Group III was injected with propofol with a dilution of ringer lactate, into 5 mg/ml liquid. Result and Discussion: The level of pain was evaluated afterward, with responding to the four-point scale and spontaneous expression. Patients’ blood pressure, mean arterial pressure, heart rate, and oxygen saturation were also examined after injection. Compared to the control group, those in groups with 5% dextrose-diluted and ringer lactate-diluted propofol are not effective in reducing intravenous injection pain, with analytical statistics p=0.503 (p > 0.05). Also, the dilution of propofol has no significant difference to the hemodynamic measurement of patients. Systolic and diastolic blood pressure, and mean arterial pressure were declined after the induction, but statistically insignificant. The heart rate of patients was inclined but also not significant. Conclusion: 5% dextrose-diluted and ringer lactate-diluted propofol with a comparison of 1:1 were not significantly effective in reducing intravenous injection pain in pediatric patients.

Hypotensive and Regional Haemodynamic Effects of Exercise, Fasted and after Food, in Human Sympathetic Denervation

1998 ◽  
Vol 94 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Sharmini Puvi-Rajasingham ◽  
Gareth D. P. Smith ◽  
Adeola Akinola ◽  
Christopher J. Mathias
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Superior Mesenteric Artery ◽  
Vascular Resistance ◽  
Mesenteric Artery ◽  
Autonomic Failure ◽  
Sympathetic Denervation ◽  
Stroke Distance

1. In human sympathetic denervation due to primary autonomic failure, food and exercise in combination may produce a cumulative blood pressure lowering effect due to simultaneous splanchnic and skeletal muscle dilatation unopposed by corrective cardiovascular reflexes. We studied 12 patients with autonomic failure during and after 9 min of supine exercise, when fasted and after a liquid meal. Standing blood pressure was also measured before and after exercise. 2. When fasted, blood pressure fell during exercise from 162 ± 7/92 ± 4 to 129 ± 9/70 ± 5 mmHg (mean arterial pressure by 22 ± 5%), P < 0.0005. After the meal, blood pressure fell from 159 ± 8/88 ± 6 to 129 ± 6/70 ± 4 mmHg (mean arterial pressure by 22 ± 3%), P < 0.0001, and further during exercise to 123 ± 6/61 ± 3 mmHg (mean arterial pressure by 9 ± 3%), P < 0.01. The stroke distance—heart rate product, an index of cardiac output, did not change after the meal. During exercise, changes in the stroke distance—heart rate product were greater when fasted. 3. Resting forearm and calf vascular resistance were higher when fasted. Calf vascular resistance fell further after exercise when fasted. Resting superior mesenteric artery vascular resistance was lower when fed; 0.19 ± 0.02 compared with 032 ± 0.06, P < 0.05. After exercise, superior mesenteric artery vascular resistance had risen by 82%, to 0.53 ± 0.12, P < 0.05 (fasted) and by 47%, to 0.29 ± 0.05, P < 0.05 (fed). 4. On standing, absolute levels of blood pressure were higher when fasted [83 ± 7/52 ± 7 compared with 71 ± 2/41 ± 3 (fed), each P < 0.05]. Subjects were more symptomatic on standing post-exercise when fed. 5. In human sympathetic denervation, exercise in the fed state lowered blood pressure further than when fasted and worsened symptoms of postural hypotension.

scholarly journals EFFECT OF ORAL MOXONIDINE IN THE ATTENUATION OF THE HAEMODYNAMIC RESPONSES SEEN DURING LAPAROSCOPIC SURGERIES

2017 ◽  
Vol 10 (3) ◽  
pp. 409
Author(s):  
Sidharth Sraban Routray ◽  
Ramakanta Mohanty
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Placebo Group ◽  
Stress Response ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Significant Rise ◽  
Hemodynamic Stability ◽  
Blinded Study ◽  
Double Blinded

ABSTRACTObjective: During laparoscopic surgeries, pneumoperitoneum can lead to various pathophysiologic changes in the cardiovascular system resulting inhypertension and tachycardia. Search for ideal drug to prevent this hemodynamic response goes on. The aim of our study was to evaluate the effect oforally administered moxonidine in attenuating the hemodynamic responses that occur during the laparoscopic surgeries.Methods: A total of 50 adult acetylsalicylic acid I and II patients scheduled for elective laparoscopic surgeries were selected for this prospectiverandomized double-blinded study. They were randomly allocated into two groups: moxonidine group (M) and placebo group (P). M group receivedoral moxonidine 0.3 mg at 8 pm on the day before surgery and at 8 am on the day of surgery. P group received a placebo at the same timing as that ofthe M group.Results: Following pneumoperitoneum rise in systolic blood pressure (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and heart rate (HR)was higher in P group in comparison to M group which was statistically significant.Conclusion: Significant rise in HR, SBP, DBP, and mean BP was noted in the P group in comparison to moxonidine group. Moxonidine provided betterperioperative hemodynamic stability in patients undergoing laparoscopic surgeries.Keywords: Moxonidine, Stress response, Laparoscopic.

scholarly journals Comparison of Ropivacaine-Fentanyl with Bupivacaine-Fentanyl for Labour Epidural Analgesia

2020 ◽  
Vol 14 (1) ◽  
pp. 108-114
Author(s):  
Kalpana Kulkarni ◽  
Rahul Patil
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Epidural Analgesia ◽  
Diastolic Blood Pressure ◽  
Diastolic Pressure ◽  
Vas Score ◽  
Group I ◽  
Significant Difference ◽  
Labour Epidural Analgesia ◽  
Group Ii

Background: Bupivacaine with opioid is commonly used for labour epidural analgesia. Ropivacaine is considered as an alternative to bupivacaine due to its lower cardiovascular complications. However, there is a controversy regarding the efficacy of these drugs as some studies suggest equivalent action, whereas others report that ropivacaine produces less motor blockade. The study aimed to compare the effect of ropivacaine-fentanyl and bupivacaine-fentanyl for labour analgesia. Materials and Methods: The prospective randomized study was performed on 60 parturients, divided into two groups of 30 subjects each. Group I received 10ml of bupivacaine 0.1% + fentanyl 2µg/ml and Group II received 10ml of ropivacaine 0.1% + fentanyl 2µg/ml by epidural catheter. Pre-anaesthetic evaluation was performed on all the participants and all were administered metoclopramide 0.25mg/kg and ondansetron 0.08-0.1mg/kg intravenously as premedication. The baseline and post anaesthesia systolic, diastolic blood pressure, heart rate, VAS score, degree of motor block, sedation and APGAR score of the baby were recorded. The data were tabulated and statistically analyzed. Results: When compared, there was no significant difference in systolic/diastolic blood pressure in two groups except at 360 min where diastolic pressure was low in group II. Significantly higher heart rate at 30 min (P=0.0003), 120 min (0.006), and 300 min (P=0.001) was observed in group I subjects. VAS score was significantly less at 180 min (P=0.019) and 300 min (P=0.019) in group II. Adverse effects such as fetal bradycardia, nausea/vomiting and hypotension observed were clinically insignificance when compared in two groups. Conclusion: Bupivacaine and ropivacaine produce an equal degree of analgesia and hemodynamic stability in 0.1% of concentration when added with 2µg/ml fentanyl . However, heart rate was well maintained with lower VAS scores in group II receiving ropivacaine. No significant difference in the side effects between the two groups. Hence, Ropivacaine can be used as a safe alternative to bupivacaine for labour epidural analgesia.

scholarly journals Comparison of Epidural and Spinal Anesthesia Techniques for Transurethral Resections

2018 ◽  
Vol 9 (1) ◽  
pp. 1-10
Author(s):  
Elif Copuroglu ◽  
Gonul Sagiroglu ◽  
Beliz Bilgili ◽  
Sevtap Hekimogl
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Spinal Anesthesia ◽  
Epidural Anesthesia ◽  
Total Duration ◽  
Satisfaction Score ◽  
Patient Satisfaction Score ◽  
Group I ◽  
Anesthesia Group ◽  
Spinal Anesthesia Group

Purpose: Transurethral resections (TUR) are commonly performed for elderly population who have multiple comorbidities which can cause intraoperative and postoperative complications. The type of anesthesia has an impact on patient outcome. The aim of the study is to compare the effectiveness of epidural and spinal anesthesia techniques for TUR. Methods: A total of 158 elective TUR cases were evaluated. The patients were randomized into 2 groups: Epidural anesthesia was applied to Group I (n=82) and spinal anesthesia was applied to Group II (n=76). Both groups were compared for intraoperative hemodynamic parameters (mean arterial pressure, heart rate, peripheral oxygen saturations), total duration of hospital stay, perioperative complications, and satisfaction of the patients and surgeons. Results: The patients in the spinal anesthesia group experienced more frequent intraoperative hypotensive episodes during TUR (n=2 vs. n=10; p=0.026) and had lower mean arterial pressure values for the first 30 minutes of anesthesia compared to epidural anesthesia group. The postoperative duration of bed stay was longer in the spinal anesthesia group (402.96±49.61 min) than the epidural anesthesia group (205.91±28.27 min) (p<0.001). The patient satisfaction score was significantly higher in the epidural anesthesia group (2.54±0.63) than the spinal anesthesia group (2.23±1.22) (p=0.04) where as the surgeon satisfaction score were similar in both groups. Conclusion: Epidural anesthesia can be considered as an effective and safe technique for ambulatory interventions especially for elderly patients providing perioperative hemodynamic stability and postoperative early mobilization.

Carotid arterial hemodynamics in response to LBNP in normal subjects: methodological aspects

1995 ◽  
Vol 79 (5) ◽  
pp. 1546-1555 ◽  
Author(s):  
B. Pannier ◽  
M. A. Slama ◽  
G. M. London ◽  
M. E. Safar ◽  
J. L. Cuche
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Pressure Wave ◽  
Plasma Norepinephrine ◽  
Tensile Forces ◽  
Cyclic Changes ◽  
Carotid Arterial ◽  
Tangential Tension

Pulsatile changes in blood pressure and arterial diameter were studied noninvasively with applanation tonometry and echo-tracking techniques at the sites of the common carotid artery (CCA) and the carotid arterial bulb (CAB) in 12 healthy volunteers. Determinations were performed before and during application of -10 and -40 mmHg lower body negative pressure (LBNP) to investigate noninvasively the tensile forces acting on the CAB. Together with significantly decreased mean arterial pressure, increased heart rate, forearm vascular resistance, and plasma norepinephrine, the -40 mmHg LBNP stimulus produced the following significant changes in CCA and CAB hemodynamics: 1) for the same decrease in mean arterial pressure, a greater decrease in carotid than in brachial pulse pressure was observed (P < 0.01) due to a significant change in pressure wave transmission and in the timing of the carotid backward pressure wave; and 2) a highly significant decrease in pulsatile changes in diameter and tangential tension occurred, with a greater decrease in systolic than in diastolic tangential tension. Subsequently, cyclic tangential tension decreased more substantially than mean tangential tension. The cyclic changes in tension were quite significant after -40 mmHg LBNP but were already observed for mild -10 mmHg LBNP in which mean systemic blood pressure and heart rate were not modified. During -10 and -40 mmHg LBNP, CCA and CAB compliance and distensibility were unchanged. This study provides evidence that the autonomic nervous system activation produced by the LBNP procedure is associated with significant changes in pressure-wave amplification and in cyclic tensile forces acting on the CAB. These changes, which may occur even for mild LBNP, should be taken into account when interpreting results of the LBNP procedure in humans.

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