Left Lateral Recumbent Position Research Articles

Maternal rest improves growth in small-for-gestational-age fetuses (

Optimal management of fetuses diagnosed as small for gestational age based on an estimated fetal weight of <10th percentile represents a major clinical problem. The standard approach is to increase fetal surveillance with serial biometry and antepartum testing to assess fetal well-being and timing of delivery. Observational studies have indicated that maternal rest in the left lateral position improves maternal cardiac output and uterine blood flow. However, maternal bed rest has not been recommended based on the results of a randomized clinical trial that showed that maternal rest does not improve fetal growth in small-for-gestational-age fetuses. This study was conducted to revisit this question. This study aimed to determine whether maternal bed rest was associated with an increase in the fetal biometric parameters that reflect growth after the diagnosis of a small-for-gestational-age fetus. A retrospective study was conducted on fetuses who were diagnosed as small for gestational age because of an estimated fetal weight of <10th percentile for gestational age. The mothers were asked to rest in the left lateral recumbent position. Fetal biometry was performed 2 weeks after the diagnosis. All fetuses before entry into the study had a previous ultrasound that demonstrated an estimated fetal weight of >10th percentile. To assess the response to bed rest, the change in fetal biometric parameters (estimated fetal weight, head circumference, abdominal circumference, and femur length) after the recommendation of bed rest was computed for 2 periods: (1) before the diagnosis of a weight of <10th percentile vs at the time of diagnosis of a weight of <10th percentile and (2) at the time of diagnosis of a weight of <10th percentile vs 2 weeks after maternal bed rest. For repeated measures, proportions were compared using the McNemar test, and percentile values were compared using the Kruskal-Wallis test. A P value of <.05 was considered significant. To describe changes in the estimated fetal weight without bed rest, 2 control groups in which the mothers were not placed on bed rest after the diagnosis of a small-for-gestational-age fetus were included. A total of 265 fetuses were observed before and after maternal bed rest. The following were observed in this study: (1) after 2 weeks of maternal rest, 199 of 265 fetuses (75%) had a fetal weight of >10th percentile; (2) the median fetal weight percentile increased from 6.8 (interquartile range, 4.4-8.4) to 18.0 (interquartile range, 9.5-29.5) after 2 weeks of bed rest; (3) similar trends were noted for the head circumference, abdominal circumference, and femur length. In the groups of patients who were not asked to be on bed rest, a reassignment to a weight of >10th percentile at a follow-up examination only occurred in 7 of 37 patients (19%) in the Texas-Michigan group and 13 of 111 patients (12%) in the Colorado group compared with the bed rest group (199/265 [75%]) (P<.001). Patients who were prescribed 2 weeks of bed rest after the diagnosis of a fetal weight of <10th percentile had an increase in weight of >10th percentile in 199 of 265 fetuses (75%). This increase in fetal weight was significantly higher than that in the 2 control groups in which bed rest was not prescribed. This observation suggests that bed rest improves fetal growth in a subset of patients.

The Effect Of Dıfferent Body Posıtıons On Calf Blood Pressure: A Cross-Sectional Study

The calf area is an alternative measurement site when blood pressure cannot be measured at the arm. To determine the effects of different body positions on calf blood pressure readings in healthy young students. A total of 100 healthy young students who agreed to participate in the study were randomly selected. The study was carried out in Aydın Adnan Menderes University Nursing Faculty. In all participants, blood pressure was measured in four positions: supine, prone, right lateral, and left lateral recumbent. All measurements were performed three times at 1-min intervals, and the results were compared. There was no statistically significant difference between the systolic and diastolic blood pressure measurements in the supine and prone positions (p&gt;0.05). The systolic blood pressure value was significantly lower in the left lateral recumbent position than in the other positions (p

Dystocia and its management in a captured wild Monkey

A stray wild female monkey, aged 5-6 years were presented to the Referral Veterinary Polyclinics, ICAR- Indian Veterinary Research Institute, with a history of straining and discharge from the vulva since morning. A close physical examination of the external genitalia of the monkey revealed it as prominent, red and swollen implying pregnancy. The vulva was open due to the internal pressure revealing foetal part visible with reduced fetal fluid. Per-vaginal examination revealed a foetal head in the birth canal, but absence of foetal responses. Per vaginal examination revealed foetal presentation to be anterior longitudinal, dorso-sacral position, but it was difficult to palpate postural condition. To relieve the condition female monkey was positioned in a left lateral recumbent position followed by ample lubrication of the birth canal with CMC (Carboxymethyl cellulose) gel using an intrauterine catheter and syringe. The traction approach was used to extract the dead foetus. Following successful delivery bleeding was prevented by administering ethamsylate injections at a dose rate of 15 mg/Kg (1 ml), and other supportive medications were administered. The macaque monkeys can postpone labour making it difficult for an observer to determine the indicators of dystocia until the condition has worsened. This makes dystocia in nonhuman primates a grave condition requiring prompt medical attention.

Effect of positioning on blood pressure measurement in pregnancy.

Blood pressure is the key vital sign to detecting hypertensive disorders in pregnancy. The importance of taking blood pressure properly was recently underscored by the publication of updated ACC/AHA guidelines for measuring blood pressure in patients. However, the recommended position of seating with arms and back supported is not always feasible to achieve clinically, especially for inpatient women who are pregnant. Therefore, it is clinically important to understand the effects of alternative patient positioning on blood pressure measurements. We conducted a review of studies which considered patient position on the effect of blood pressure in pregnancy. This review demonstrates that clinically significant differences may occur based on patient positioning. Despite the small number of primary studies that include pregnant women, notable reductions in blood pressure measurements have been observed in the left lateral recumbent position, a common position during labor or during monitoring, in comparison to measurements taken in the supported seated position. Ultimately, these differences could affect the clinical management of patients and care should be taken to document and consider the position in which the reading was taken.

645 Effects of position on blood pressure measurement in pregnancy

Hypertension in pregnancy is a leading cause of maternal morbidity and mortality. Studies demonstrate that body positions affect the blood pressure (BP) measurements and have led to guidelines for proper positioning by the ACC and AHA. However, studies excluded pregnant women and did not include all common patient positions, such as semi-Fowlers. These studies cannot be applied to pregnant women due to dynamic cardiovascular changes in pregnancy. Our objective was to determine if common patient positions affect BP measurements in pregnant women. This was a prospective study (N=61). We measured BP in pregnant women in inpatient and outpatient settings in several positions including semi-Fowler’s, seated without back and arm support (as on an exam table), and left lateral recumbent. The order of the measurements was randomized, and participants were kept sitting still for 5 minutes between positions. The measurements were compared to BP measurements observed in the published ACC/AHA guideline position: seated with arms and feet supported. Trained team members used an aneroid sphygmomanometer and stethoscope and/or a validated electronic BP machine. There is no significant difference between BP measurements using a sphygmomanometer/stethoscope vs. an electronic BP machine in the ACC/AHA guideline position (systolic p=0.60 diastolic p=0.91). There was not a significant difference in either systolic or diastolic means in the semi-Fowlers position (at 45 degrees measured by goniometer) (systolic P=0.60 diastolic P=0.95). Positioning did affect the diastolic BP measurement in the seated without support position (p=0.01) and both the systolic (p< 0.0001) and diastolic (p<0.0001) measurements in the left lateral recumbent position. Our data demonstrate that an accurate BP measurement in pregnancy is dependent upon patient position. Blood pressure measurements in left lateral recumbency result in clinically significant variation in pregnant women. Semi-Fowler's is a clinically reasonable alternative for measuring blood pressure when pregnant patients need to be lying down.

Abstract P186: Position Effects Blood Pressure Measurement During Pregnancy

Hypertension in pregnancy is a leading cause of maternal morbidity and mortality. Studies demonstrate that body positions affect the blood pressure (BP) measurements and have led to guidelines for proper positioning by the ACC and AHA. However, studies excluded pregnant women and did not include all common patient positions, such as semi-Fowlers. These studies cannot be applied to pregnant women due to dynamic cardiovascular changes in pregnancy. We measured BP in pregnant women in inpatient and outpatient settings in various positions. These BPs were compared to the published ACC/AHA guideline position: seated with arms and feet supported. Trained team members used an aneroid sphygmomanometer and stethoscope and/or a validated electronic BP machine. There is no significant difference between BP measurements using a sphygmomanometer/stethoscope vs. an electronic BP machine in the ACC/AHA guideline position (systolic p=0.60 diastolic p=0.91). There was not a significant difference in either systolic or diastolic means in the semi-Fowlers position (at 45 degrees measured by goniometer) (systolic=0.60 diastolic=0.95). Positioning did affect the diastolic BP measurement in the seated without support position (p=0.01) and both the systolic (p&lt; 0.001) and diastolic (p&lt;0.001) measurements in the left lateral recumbent position. Our data demonstrate that an accurate BP measurement in pregnancy is dependent upon patient position. Monitoring BP position in left lateral recumbent may mask an elevated BP. This study also suggests that it may be possible to substitute semi-Fowlers position for reliable BP measurements when chair sitting is not practical, such as labor.

Selection of Patients' Recumbent Position Laterality According to Physician Handedness Bias Increases the Success Rate of Lumbar Puncture: A Multicenter Study.

Lumbar puncture (LP) is a medical procedure required during spinal anesthesia and for obtaining cerebrospinal fluid samples in the diagnosis of neurological disorders. The aim of this study was to assess the effects of physicians' handedness bias and the laterality of patients' recumbent position on the success rate of LPs. A prospective multicenter study including 36 physicians (18 left-handed and 18 right-handed) and 7200 patients was conducted in 6 medical centers. In each center, 1200 patients were randomized into group L (LPs performed by left-handed physicians) or group R (LPs performed by right-handed physicians). Each physician performed 200 cases of LPs, of which the laterality of the recumbent position (either on the left or right side) was decided after a second randomization. A successful LP was considered when the free flow of cerebrospinal fluid was observed upon the first attempt. There was no significant difference in patient characteristics between groups L and R. Right-handed physicians had a significantly higher LP success rate with patients in the left lateral recumbent position (LRP) (1595/1800 vs. 1408/1800; odds ratio, 0.539; 95% confidence interval, 0.348-0.836; P=0.006). For left-handed physicians, the LP success rate was higher when patients were in the right LRP (1424/1800 vs. 1593/1800, odds ratio, 0.449; 95% confidence interval, 0.283-0.711; P=0.001). Patients' age, sex, height, and weight were not statistically related to LP success during multivariate analyses. Physicians handedness bias and patient laterality of recumbent position affects the success of LPs. Right-handed physicians have a greater chance of performing successful LPs when patients are in the left LRP, and vice versa.

Measurement of Renal Hemodynamics by Doppler Ultrasound during Sympathetic Activation while Heat Stressed

P‐aminohippurate clearance demonstrates that passive heat stress increases renal vascular resistance (RVR) in proportion to increases in core temperature. These heat stress evoked elevations in RVR are exacerbated during exercise, a sympathetic stimulus. Passive heat stress attenuates the vascular response to the cold pressor test (CPT), a non‐exercise sympathoexcitatory maneuver. However, the effect of passive heating on renal vascular responsiveness to a non‐exercise sympathoexcitatory stimulus is unknown.PurposeTest the hypothesis that passive heat stress augments increases in RVR during the CPT compared to normothermia.MethodsEight healthy adults (aged 22 ± 1 y, 3 F) completed a CPT by immersing their right hand in an agitated ice slurry mixture for 2 min during normothermia (Normothermia), and after intestinal temperature increased by 1.3 ± 0.1°C following passive heating with a water perfused suit (Heated). Mean arterial pressure (MAP, finger photoplethysmography), heart rate (HR, 3 lead ECG) and renal blood velocity (RBV) were measured at 1 min pre‐CPT, and at 1 and 2 min into the CPT (T1 and T2). RBV was assessed in the distal segment of the right renal artery during the same phase of the respiratory cycle via Doppler ultrasound (GE Vivid 7 Dimension). The coronal approach was utilized using a linear‐array transducer with a 2.5–3.5 MHz pulsed frequency, and participants assumed the left lateral recumbent position. All measurements were obtained by the same sonographer with the focal zone set to the artery's depth, and the transducer held in the same location at an insonation angle &lt;60°. RVR was calculated as MAP/RBV. RBV and RVR were averaged across 2–4 beats. Data are presented as the absolute change from pre‐CPT (mean ± SD) unless otherwise stated.ResultsPre‐CPT, MAP was lower (76 ± 8 vs 84 ± 7 mmHg; P&lt;0.01) and HR was higher (101 ± 14 vs 60 ± 6 bpm; P&lt;0.01) in Heated. RBV was lower (Heated: 31.3 ± 5.0 Normothermia: 34.9 ± 2.4 cm · s−1; P=0.05), but RVR did not differ (Heated: 2.5 ± 0.7, Normothermia: 2.4 ± 0.2 mmHg · cm−1 · s‐1; P=0.67) between Normothermia and Heated pre‐CPT. Elevations in MAP (T1: 22 ± 12; T2: 26 ± 13 mmHg) and HR (T1: 16 ± 8; T2: 13 ± 6 bpm) during Normothermia differed from the MAP (T1: 5 ± 3; T2: 2 ± 2 mmHg) and HR (T1: 3 ± 11; T2: 1 ± 10 bpm) response evoked by the CPT during Heated (P&lt;0.01). Changes in RBV during the CPT did not differ between Heated and Normothermia at T1 (Heated: −2.5 ± 6.2; Normothermia: −4.0 ± 4.9 cm · s−1, P=0.94) or T2 (Heated: 0.9 ± 5.8; Normothermia: −4.0 ± 4.9 cm · s−1, P=0.97). Changes in RVR did not differ between Heated and Normothermia at T1 (Heated: 0.4 ± 0.6, Normothermia: 1.1 ± 1.0 mmHg · cm−1 · s‐1; P=0.10), but were lower in Heated at T2 (0.0 ± 0.4, vs 1.1 ± 1.0 mmHg · cm−1 · s‐1; P&lt;0.02).ConclusionThese data indicate that passive heat stress attenuates Doppler ultrasound derived measures of renal vascular responsiveness to the CPT, a non‐exercising sympathoexcitatory stimulus.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A Comparasion of Laboratory and Cardiopulmonary Effects of Desflurane, Detomidine and Medetomidine Anaesthetic Combinations in Horses

Background: Equine anesthesia morbidity and mortality rates are greater than in other domestic animals because of hypotension and hypoventilation. The important features desired in general anesthesia for horses are a rapid effect, rapid emergence and balanced anesthesia. The long duration of action of currently used anesthetic agents cause various complications in horses. The aim of the present study was to compare the clinical effects of combination of the anesthetics desflurane, detomidine and medetomidine in horses.Materials, Methods &amp; Results: Eight healthy mixed-breed horses (four males and four females) with weighing 275 ± 56 kg [mean ± standard deviation (SD)] and aged 6.8 ± 5 years [(mean ± SD)] were used for this study. The horses were placed into one of four groups: group I (detomidine-desflurane), group II (detomidine-desflurane-atipamezole), group III (medetomidinedesflurane), or group IV (medetomidine-desflurane-atipamezole). Horses were rested for 15 days before each group starts to study. Intravenous detomidine (25 µg/kg) was used for premedication in groups I and II, and intravenous medetomidine (7 µg/ kg) was used for premedication in groups III and IV. Ketamine hydrocholoride (2 mg/kg) and midazolam (0.03 mg/kg) were intravenously administered in the same syringe to induce anesthesia. After induction of anesthesia, horses were placed in the left lateral recumbent position, and the trachea was intubated with a cuffed endotracheal tube with an internal diameter of 28 mm. The endotracheal tube was attached to a large animal circle breathing system anesthesia machine, and anesthesia was maintained with desflurane for 90 min. The initial dosage of desflurane was 14% + 4 L O2/min, and was reduced by 2% every 10 min over the first 30 min of anesthesia. After 30 min, the desflurane dose was changed to 8% + 4 L, which was maintained until the end of anesthesia (90 min). After 90 min, the administration of desflurane was discontinued, and all animals were supported by O2, with groups II and IV receiving 0.06 mg/kg atipamezole in addition to oxygen. Anaesthetic action times, hematological parameters, blood gas levels, electrolyte levels, biochemical values, electrocardiography values and end-tidal carbon dioxide volume were measured before, during, at the end of, and 24 h after anesthesia.Discussion: In this study, medetomidine (7 µg/kg) and detomidine (25 µg/kg) were intravenously administered, which was adequate and suitable for sedating horses. At the end of anesthesia, 0.06 mg/kg atipamezole was intravenously administered in groups II and IV. However, atipamezole did not affect the clinical parameters. Stress, excitement, fear, catecholamine exchange in blood circulation, hyperglycemia, and hypoxia can all cause changes in venous blood parameters. These are potential reasons for the changes in venous blood parameters (i.e., WBC and Hb) observed at the beginning of and during anesthesia in the present study. During and after the anesthetic period, serum biochemical values can be different from baseline values. They are dependent on the effects of anesthetic agents. During anesthesia, the decrease and increase of biochemical values stabilize the changes in the enzyme system that develops because of the effects of anesthetic agents. In the present study, it was considered that the changes in the biochemical values aimed to stabilize the changes induced by anesthesia. Regarding the electrolyte parameters evaluated in the study, there was a statistical difference detected in Na values between 90 min after induction of anesthesia and 24 h after induction of anesthesia in group IV. However, in previous studies, the changes in Na values did not influence the cardiac pressure during general anesthesia. In our study, significant changes were not seen in any electrolyte parameters except Na, and atrioventricular block was not detected in ECG traces. Generally, decreased ETCO2 levels are evidence of lung perfusion deficiency. It depends on the effects of anesthetic agents on the cardiopulmonary, cardiovascular, and respiratory systems. In particular, the higher pressure and dose of desflurane supress respiratory system. Oxygen supplementation in general anesthesia increases respiratory rate, but a-2 agonists and ketamine-midazolam effects can eliminate the increasing respiratory rate in general anesthesia.

O62. Use of diuretics in the management of late-onset preeclampsia

Introduction Hemodynamic examinations revealed high cardiac output (CO) in a portion of preeclamptic patients. These cases in our study population met the criteria for late-onset subtype of the disease as hypertension and proteinuria appeared beyond the 33rd gestational week. Objectives To decrease enormously high blood volume, as the possible reason for hypertension and edema, diuretics were applied in preeclamptic women with high CO, and edema. Methods After a short rest on the left lateral recumbent position, blood pressure (BP), and, by the use of impedance cardiography, CO and systemic vascular resistance (SVR) were determined. In the absence of relative hemoconcentration (hematocrit 37 l/l) 40 mg of furosemide was administrated orally in 10 cases. Examinations were repeated after 60 minutes of rest. Looking for the effects of the diuretics identical data (before and after furosemide medication) were compared by paired t -test. Significant difference was determined as p 0.05. Results In most of cases furosemide administration resulted in a lowering of CO and also BP. Heart rate and SVR remained stable, therefore change of CO was due to blood volume decrease. Download : Download full-size image Conclusion Our preliminary data draw attention to the possible use of diuretics in the management of late-onset preeclampsia and support the presumption that increased water retention may play a role in the development of hypertension in late-onset gestational hypertension or preeclampsia. Our data also suggest that the pathogenesis of late-onset preeclampsia is basically different from “classical” preeclampsia characterized by low CO. *The study was supported by TAMOP 4.2.2.D-15/1/KONV-2015-0004

The effect of body position on postprandial perceptions, gastric emptying, and intragastric meal distribution: An ultrasonographic study in reclining healthy subjects

Objective. Postprandial dyspepsia is common and may be associated with abnormal intragastric distribution of food. We aimed to determine the effect of body position on gastric emptying, meal distribution, and postprandial perceptions in healthy subjects. Material and methods. Eight adolescents (4 females and 4 males aged 14 years) were investigated using three-dimensional ultrasonography. The subjects were studied twice in a random order: once in the right lateral recumbent (RLR) position and once in the left lateral recumbent (LLR) position. Postprandial perceptions, gastric volumes, and antral areas were recorded immediately after the ingestion of 500 ml of a low-caloric meat soup over 4 min, and at 10 and 20 min following the meal. Results. Postprandial perceptions (epigastric pain, nausea, and fullness) were more pronounced in the RLR position compared to the LLR position, particularly at the end of the meal ingestion (p < 0.01). Gastric volumes were significantly smaller in the RLR position compared to the LLR position at 10 min (p < 0.01) and 20 min (p < 0.05). Antral areas were significantly wider in the RLR position compared to the LLR position at 10 min (p < 0.05) and 20 min (p < 0.01). Conclusion. Postprandial perceptions are more pronounced, gastric emptying is faster, and antral area is wider in the RLR position compared to the LLR position. The results suggest that lying on the left side after a meal may be a measure to reduce postprandial dyspeptic sensations.

Dynamic clinical measurements of voluntary vaginal contractions and autonomic vaginal reflexes.

The vaginal canal is an active and responsive canal. It has pressure variations along its length and shows reflex activity. At present, the prevailing idea is that the vaginal canal does not have a sphincter mechanism. It is hypothesized that an active vaginal muscular mechanism exists and might be involved in the pathophysiology of genito-pelvic pain/penetration disorder. The aim of this study was to detect the presence of a canalicular vaginal "sphincter mechanism" by measuring intravaginal pressure at different levels of the vaginal canal during voluntary pelvic floor contractions and during induced reflexive contractions. Sixteen nulliparous women, without sexual dysfunction and pelvic floor trauma, were included in the study. High-resolution solid-state circumferential catheters were used to measure intravaginal pressures and vaginal contractions at different levels in the vaginal canal. Voluntary intravaginal pressure measurements were performed in the left lateral recumbent position only, while reflexive intravaginal pressure measurements during slow inflation of a vaginal balloon were performed in the left lateral recumbent position and in the sitting position. Intravaginal pressures and vaginal contractions were the main outcome measures. In addition, a general demographic and medical history questionnaire was administered to gain insight into the characteristics of the study population. Fifteen out of the sixteen women had deep and superficial vaginal high-pressure zones. In one woman, no superficial high-pressure zone was found. The basal and maximum pressures, as well as the duration of the autonomic reflexive contractions significantly exceeded the pressures and the duration of the voluntary contractions. There were no significant differences between the reflexive measurements obtained in the left lateral recumbent and the sitting position. The two high-pressure zones found in this study, as a result of voluntary contractions and, even more pronounced, as a result of reflexive contractions on intravaginal stimulation, support the hypothesis that the vaginal canal has an active and passive canalicular sphincter mechanism. Further investigation of this sphincter mechanism is required to identify its role in the sexual response and genito-pelvic pain/penetration disorder.

EComment. Cardiopulmonary bypass and pregnancy

We read with great interest the article by Sepehripour et al. regarding the safety of performing cardiac surgery on cardiopulmonary bypass (CPB) during pregnancy [1]. They included in the results of their research three retrospective literature reviews (published in 1996 and 1998), three retrospective observational studies and eight case reports describing 10 parturients undergoing CPB. However, we found three additional relevant articles investigating the outcome of pregnancy after CBP. In order to be exhaustive, we will summarize the relevant results of the omitted papers. Thalmann et al. [2] performed a population-based study covering a period of 10 years in Austria and found 2 pregnant patients (at 36 and 32 weeks of pregnancy) with acute aortic dissection. Emergent surgery was successful for both patients and their offspring. The relevant result of the study is that pregnancy may not be a risk factor for acute aortic dissection and hence contradicts the findings of previous studies. Guo et al. [3] reported two cases of acute aortic dissection during the third trimester. The first was a 33-year old parturient with Marfan syndrome who underwent a successful Bentall procedure at 28 weeks of gestation, and the second was a 30-year old pregnant patient at 32 weeks of pregnancy who underwent an uneventful aortic root replacement. Both patients underwent a caesarean section immediately before CBP. We recently reported a successful surgical pulmonary embolectomy under CBP [4]. The patient was a 39-year old at 25 weeks of pregnancy who underwent an emergent surgery due to a massive pulmonary embolism with haemodynamic compromise. In this case of heparin-induced thrombocytopenia, we chose to carry out a surgical embolectomy because we were familiar with performing this procedure when fibrinolytic therapy is contraindicated. On the basis of accumulating evidence of encouraging results, we believe it is reasonably safe to perform cardiac surgery during pregnancy at tertiary centres with expertise using additional strategies to minimize maternal and foetal risks (normothermic CBP with high flow rate and left lateral recumbent position) [5]. The maternal mortality rate is reported to be comparable to that of CPB in non-pregnant women, except in the emergent cases. In the other hand, the foetal mortality rate decreases when cardiac surgery is postponed and the foetus is allowed to mature. Conflict of interest: none declared

Surface electromyography signals from neck muscles during different craniocervical postures in a lateral recumbent position

Objective To survey cervical myoelectric signals during craniocervical flexion, neutral and extension postures, and to explore the evidence that proper head position can alleviate cervical muscle fatigue in a lateral recumbent position. Methods Surface electromyography (sEMG) signals were detected from the sternocleidomastoid, upper trapezius and erector spinae muscles of 30 young subjects bilaterally during craniocervical flexion,neutral and extension postures in the left lateral recumbent position. The integrated trace area (IEMG) and median frequency (MF) were estimated. Results The average IEMG of the sternocleidomastoid muscles was significantly lower in flexion than in extension bilaterally. The average IEMG of the erector spinae muscles was lower in extension than in flexion bilaterally, and the difference was again significant. The IEMGs of the upper trapezius muscle showed no significant difference on average in the three postures bilaterally. There was no significant MF difference in any of the muscles. Conclusions The muscles in the cervical back were less activated during craniocervical extension in a lateral recumbent position. A little cranicocervical extension is optimal while resting in a lateral recumbent position. Key words: Surface electromyography; Lateral recumbent position; Sternocleidomastoid muscle; Cervical erector spinae muscle; Upper trapezius muscle

Venous Air Embolism during Total Laparoscopic Hysterectomy

We read with great interest the article by Kim et al. 1in the July 2009 issue of Anesthesiology. In this study, the authors warn us of the high frequency of venous gas embolism that can occur during laparoscopic hysterectomy as opposed to total abdominal hysterectomy. Their study calls for several comments.The authors found approximately 25% of patent foramen ovale (PFO) among their patients, which is consistent with what we know from autopsic series.2However, the detection of a PFO could have been enhanced by an end-inspiratory occlusion maneuver or by the application of positive end-expiratory pressure during transesophageal echocardiography.3–5No indication on the filling of the left heart by bubbles, especially for patients presenting with a PFO, was reported. This would have informed us of the risk of systemic air embolism, which is ultimately the most daunting complication.Only major neurologic complications that are rare in clinical practice were evaluated. It would have been interesting to assess the risk of minor neurologic complications that are often underdiagnosed, especially in elderly patients.When venous air embolism occurs, the authors suggest placing the patient in a left lateral recumbent position. Animal studies have found no benefit from the left lateral position in improving hemodynamic performance,6,7and human data are lacking. Conversely, in the case of a major event, such as cerebral gas embolism, the authors did not mention hyperbaric oxygen therapy. This therapy has potential benefits in the case of arterial gas embolism8,9and has to be mentioned in the therapeutic arsenal.Finally, we are clearly faced with a paradox. Venous air embolism is frequently found during laparoscopic procedures,1,10PFO exists in 25 to 30% of patients, and mechanical ventilation increases right atrial pressure favoring right-to-left flow through a foramen ovale, especially if there is positive end-expiratory pressure.11However, systemic complications as a result of paradoxical embolism, especially cerebral complications, are rare. An explanation often evoked is the high solubility of carbon dioxide in blood. However, a gas embolism is rapidly transformed into a nongas embolism because of the adhesion of platelets to the bubble.12Moreover, if bubbles are detected in the heart, they can be in the brain, only a few seconds later through a PFO.To conclude, it is perhaps time to call for a large study allowing the evaluation of the frequency of cerebral complications of gas embolism during laparoscopic surgery, especially minor ones, and to open a database of major complications, which are possibly underestimated today and most of them not being published. After all, we want to ask a question: should we contraindicate laparoscopic surgery in patients with a known PFO and prefer total abdominal surgery?*Hôpital Foch, Suresnes, France. m.fischler@hopital-foch.org

Management of foetal asphyxia by intrauterine foetal resuscitation.

Management of foetal distress is a subject of gynaecological interest, but an anaesthesiologist should know about resuscitation, because he should be able to treat the patient, whenever he is directly involved in managing the parturient patient during labour analgesia and before an emergency operative delivery. Progressive asphyxia is known as foetal distress; the foetus does not breathe directly from the atmosphere, but depends on maternal circulation for its oxygen requirement. The oxygen delivery to the foetus depends on the placental (maternal side), placental transfer and foetal circulation. Oxygen transport to the foetus is reduced physiologically during uterine contractions in labour. Significant impairment of oxygen transport to the foetus, either temporary or permanent may cause foetal distress, resulting in progressive hypoxia and acidosis. Intrauterine foetal resuscitation comprises of applying measures to a mother in active labour, with the intention of improving oxygen delivery to the distressed foetus to the base line, if the placenta is functioning normally. These measures include left lateral recumbent position, high flow oxygen administration, tocolysis to reduce uterine contractions, rapid intravenous fluid administration, vasopressors for correction of maternal hypotension and amnioinfusion for improving uterine blood flow. Intrauterine Foetal Resuscitation measures are easy to perform and do not require extensive resources, but the results are encouraging in improving the foetal well-being. The anaesthesiologist plays a major role in the application of intrauterine foetal resuscitation measures.

Physiological Change in Nasal Patency in Response to Changes in Posture, Temperature, and Humidity Measured by Acoustic Rhinometry

Acoustic rhinometry has been used to assess nasal patency and to calculate nasal cavity volume. This study used acoustic rhinometry to assess changes in nasal patency after alterations in posture, unilateral mechanical obstruction, temperature, and humidity. Eight healthy adult volunteer subjects underwent acoustic rhinometry during the following conditions: (1) sitting position (control), (2) supine position, (3) left lateral recumbent position, (4) nostril unilaterally mechanically blocked, (5) ice pack on neck, (6) drinking cold water, (7) drinking hot water, (8) nasal nebulizer, and (9) oxymetazoline decongestant. Two distinct patterns emerged based on the total nasal cavity volumes in response to the decongestant. Subjects with initial unilateral nasal cavity volumes near the mean had an expected increase in total volume after the topical decongestant administration. There were two subjects with initial volumes of 1 SD above the mean that had a paradoxical decrease in total volume in response to the decongestant. In all subjects, there was a significant decrease in the volume of each of the nasal cavities in response to ingestion of hot water at 1 minute. There was a significant decrease in the volume of the smaller of the two nasal cavities in response to nebulizer treatment and hot water ingestion at 5 minutes. Total nasal cavity volume changes were not significant for any of the variables. Changes in nasal cavity volumes were detected by acoustic rhinometry after alterations in posture, unilateral mechanical obstruction, temperature, and humidity. Nebulizer treatment and hot water ingestion caused a significant decrease in nasal volume. The nose of a healthy patient was able to adapt to environmental and physiological changes to maintain a consistent total nasal volume within 15 minutes.

Pulmonary venous systolic flow: Influence of gravity on pulmonary venous flow velocities assessed in patients with atrial fibrillation

The origin of the pulmonary venous (PV) systolic flow wave is still unclear and could be the atrial relaxation and systolic descent of the atrioventricular plane, which decrease atrial pressure (suction) or raised PV pressure. In atrial fibrillation (AF), loss of atrial contraction and relaxation significantly modifies the systolic PV flow wave. The effect of recumbent positional changes on PV, however, has not yet been characterized in AF. The purpose of this study was to evaluate the effect of positional changes on systolic PV flow in patients with AF studied by transesophageal echocardiography. The study group consisted of 45 patients with AF (34 patients with AF, alone, and 11 patients with mitral stenosis [MS]). To assess the influence of left atrial pressure, we included patients with MS and AF. Pulsed wave Doppler transesophageal echocardiography of the left and right upper PV were performed in the left lateral recumbent position in all patients and repeated records were obtained with the subject in the supine position in 25 (AF alone: n = 20, MS: n = 5) of 45 patients. In the left lateral recumbent position, the systolic PV flow velocity and systolic fraction of the left PV, which were recorded on the recumbent subject's lower side, were significantly increased compared with those of the right PV in both AF alone and MS with AF (33.9 ± 10.8 vs 13.8 ± 6.4 cm/s, 0.45 ± 0.09 vs 0.20 ± 0.10 in AF alone; 30.2 ± 11.7 vs 14.6 ± 6.0 cm/s, 0.43 ± 0.12 vs 0.20 ± 0.07 in MS, respectively, P < .01). By changing the position from the left lateral to the supine position, systolic PV flow velocity and systolic fraction of the left and right PV became the same (29.3 ± 8.4 vs 27.9 ± 8.4 cm/s, 0.39 ± 0.09 vs 0.36 ± 0.06 in AF alone, 23.5 ± 8.8 vs 27.5 ± 5.0 cm/s, 0.35 ± 0.08 vs 0.35 ± 0.09 in MS, respectively). These findings show that the PV volume (hydrostatic pressure) significantly modifies systolic PV flow wave in patients without atrial contraction and relaxation. We should take into consideration the body position on which PV flow is studied. (J Am Soc Echocardiogr 2002;15:1087-93.)

The effect of obesity and position on heart rate in pregnancy

Objective: To determine the prevalence of resting sinus tachycardia among pregnant women during routine third-trimester antenatal visits, and to determine the relationship between body mass index (BMI) and heart rate. Methods: In this cross-sectional study, pregnant women at 32-40 weeks' gestation were evaluated at routine antenatal visits between September 1996 and August 1997. Patients with medical disorders were excluded. Height, weight and pulse in both the sitting and the left lateral recumbent position were obtained. BMI was based on current weight, and those with a BMI of ≥ 30 kg/m2 were classified as obese. Sinus tachycardia was defined as a heart rate of ≥ 100 beats/min. Results: The prevalence of tachycardia was 39% (n = 93) when seated, and 29% on the left side. The corresponding rates of sinus tachycardia when seated for obese (n = 31) and non-obese (n = 62) pregnant women were 58% and 29% (relative risk 2.0, 95% confidence interval 1.2, 3.3). However, the rates of tachycardia on the left side were not significantly different: 32% for obese and 27% for non-obese (relative risk 1.2, 95% confidence interval 0.6, 2.3). Conclusion: Resting tachycardia during routine antenatal visits may be more common than was previously recognized, and the majority of obese pregnant women are tachycardic when seated. When obese women are tachycardic in the seated position their heart rate should be reassessed after 5 min in the left lateral recumbent position.

The effect of obesity and position on heart rate in pregnancy

Objective: To determine the prevalence of resting sinus tachycardia among pregnant women during routine third-trimester antenatal visits, and to determine the relationship between body mass index(BMI) and heart rate.Methods: In this cross-sectional study, pregnant women at 32-40 weeks' gestation were evaluated at routine antenatal visits between September 1996 and August 1997. Patientswith medical disorders were excluded. Height, weight and pulse in both the sitting and the left lateral recumbent position were obtained. BMI was based on current weight, and those with a BMI of ≥ 30kg/m2 were classified as obese. Sinus tachycardia was defined as a heart rate of ≥ 100 beats/min.Results: The prevalence of tachycardia was 39% (n = 93) when seated, and29% on the left side. The corresponding rates of sinus tachycardia when seated for obese (n = 31) and non-obese (n = 62) pregnant women were 58% and 29% (relative risk 2.0, 95% confidenceinterval 1.2, 3.3). However, the rates of tachycardia on the left side were not significantly different: 32% for obese and 27% for non-obese (relative risk 1.2, 95% confidence interval 0.6, 2.3).Conclusion:Resting tachycardia during routine antenatal visits may be more common than was previously recognized, and the majority of obese pregnant women are tachycardic when seated. When obese women are tachycardicin the seated position their heart rate should be reassessed after 5 min in the left lateral recumbent position.