Simplified supine modified park bench / lateral decubitus position using a shoulder pad and a Mayfield head clamp for neurosurgical approach to lesions located in the occipital lobe or the posterior fossa: technical note.

Neurosurgical approach to lesions located in the occipital lobes or in the posterior fossa require very specific and time-consuming patient installations, such as the park bench position, the prone position, or the sitting position. Nevertheless, each of these position present major drawbacks regarding specific installation-related adverse events and potentially serious neurosurgical complications such as venous air embolism, iatrogenic intracranial hypertension, and supratentorial remote hematoma just to cite a few. In order to provide neurosurgeons with a simpler, physiologically-respective, easily tolerated, less time-consuming, and less provider or specific adverse events patient installation, Ochiai (1979) introduced the supine modified park-bench / lateral decubitus position. Given that this patient position has not gained wide visibility among the neurosurgical community despite its obvious numerous advantages over its classic counterparts, we provide our experience using this installation for neurosurgical approach to lesions located in the occipital lobes and in the posterior fossa.

Comparison of supine-prone percutaneous nephrolithotomy methods in the treatment of kidney stones in pediatric patients: prospective randomized study.

Mini-PCNL is one of the most effective surgical methods in the treatment of kidney stones in pediatric patients. In this study, we aimed to compare PCNL in the supine-prone position in pediatric patients (especially operation time, postop complications, hospital stay and stone-free rates).We conducted our study in a randomized and prospective manner. Patients with lower pole stones larger than 1 cm, stones larger than 1.5 cm in the pelvis, upper pole, midpole or multiple locations, and patients who did not respond to ESWL or whose family that preferred mini-PCNL to be the primary treatment were included in the study. Patients with any previous kidney stone surgery, patients with coagulation disorders and patients with retrorenal colon were excluded from the study. Between 2021 and 2023, a total of 144 patients underwent PCNL. 68 of these patients had supine PCNL and 76 prone PCNL. Postoperative Clavien grade1 complication occurred in a total of 7 patients in the prone position; Clavien grade1 complication occurred in 1 patient in the supine position. The mean operation time for prone PCNL was 119.88 ± 28.32 min, and the mean operative time for supine PCNL was 98.12 ± 14.97 the mean hospitalization time in prone PCNL was 3.56 ± 1.12 days, and 3.00 ± 0.85 days in supine PCNL. In conclusion, supine PCNL is a safe and effective method in the treatment of pediatric kidney stones and postoperative complications were observed to be less; the operation time and hospital stay were shorter in supine PCNL.

Effect of the early diastolic blood pressure response to the head-up tilt test on the recurrence of benign paroxysmal positional vertigo.

BACKGROUND: Otolith organ acts complementarily with the autonomic nervous system to maintain blood pressure. However, the effect of blood pressure variability in the autonomic nervous system on otolith organ has not yet been determined. This study aimed to verify the hypothesis that blood pressure variability in the autonomic nervous system affects the recurrence of benign paroxysmal positional vertigo (BPPV), which is the most common disease of the vestibular organs, by using the head-up tilt test (HUTT). METHODS: This study included 432 patients diagnosed with idiopathic BPPV. The follow-up period for all patients was 12 months. Age, sex, hypertension, diabetes and recurrence were analyzed. The HUTT parameters were divided into a group of patients whose average diastolic blood pressure increased in the upright position compared to supine position during the HUTT (DBP1) and a group of patients whose average diastolic blood pressure decreased in the upright position compared to supine position during the HUTT (DBP2). Model selection, general loglinear analysis, and logit loglinear analysis were performed using a hierarchically progressing loglinear analysis. RESULTS: In summary, the group with increased average diastolic blood pressure (DBP1) showed a higher tendency for BPPV recurrence compared to the group with decreased diastolic blood pressure (DBP2) in the upright position during the HUTT, although the difference was not statistically significant (p = 0.080). However, in males, the DBP1 group demonstrated a significantly higher recurrence rate of BPPV than the DBP2 group during the HUTT (95% CI, -20.021 to -16.200; p < 0.001). CONCLUSIONS: It is presumed that poor autonomic nervous system response through vestibulosympathetic reflex maintains elevated diastolic blood pressure in the upright position during the HUTT. This variability is assumed to affect the recurrence of BPPV.

Evaluation of airway responsiveness and pulmonary function test results among obese and non-obese patients with obstructive sleep apnea syndrome.

OBJECTIVE: In this research, we aimed to elucidate the effect of obstructive sleep apnea syndrome (OSAS) and obesity on pulmonary volumes and bronchial hyperreactivity, and particularly the effect of supine position on pulmonary volume and functions. PATIENTS AND METHODS: This was a prospective, cross-sectional study with a total of 96 patients (age range, 20-65 years). Based on the body mass index (BMI) and Apnea-Hypopnea Index (AHI) scores, the patients were divided into four groups: Group 1: AHI≥15/h, BMI≥30 kg/m2 (n=24), Group 2: AHI≥15/h, BMI<30 kg/m2 (n=24), Group 3: AHI<15/h, BMI≥30 kg/m2 (n=24), and Group 4: AHI<15/h, BMI<30 kg/m2 (n=24). All patients first had static and dynamic pulmonary function tests and carbon monoxide diffusion tests (TLco and Kco) in the sitting and supine positions. A bronchial provocation test with methacholine was applied to all patients in the sitting position one day later. Analysis of variance (ANOVA) and multivariate linear regression was used in the statistical analysis. RESULTS: Airway responsiveness was observed in 4 of the patients included in the study, and there was no statistically significant difference between the groups. A statistically significant decrease was observed in forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), total lung capacity (TLC) and functional residual capacity (FRC), especially in  Group 1 in sitting position compared to Group 4 (p=0.001, p=0.001, p=0.025, p=0.043, and p=0.001, respectively). Changes in pulmonary functions in the transition from sitting to a supine position did not show any significant difference in the study groups (p<0.05). We observed no difference in the diffusion capacity in the sitting and supine positions among the groups (p<0.05). CONCLUSIONS: The severity of AHI and BMI particularly affect the lower airway, but changes in the position did not show any significant difference in the study groups.

The effect of position on feeding performance in infants with cleft lip and palate: Quasiexperimental study.

PURPOSE: This single-group, quasiexperimental study was conducted to determine the effect of feeding position on the physiological parameters and feeding performance of term-born infants with cleft lip and palate (CLP) in the preoperative period. METHODS: The study sample consisted of 45 infants aged 0-6 months with CLP followed up preoperatively in our outpatient clinic between January 2021 and 2022. Infants who were being fed with a specialty bottle for babies with CLP and whose families consented to participate in the study were included. After 2 h of fasting, the infants were fed in the elevated supine (ESU) position for the first meal, then in the elevated side-lying (ESL) position for the second meal after another 2 h of fasting. The infants' heart rate and oxygen saturation values before, during, and after each feed and indicators of feeding performance were compared between the positions. RESULTS: There was no significant difference between the positions in terms of heart rate and oxygen saturation before, during, or after feeding (p > .05). There was no statistically significant difference in measures of feeding performance according to the infants' feeding position (p > .05). CONCLUSION: According to the findings obtained in this study, infants with CLP showed no statistically significant differences in heart rate, oxygen saturation, or feeding performance when fed in the ESL and ESU positions. PRACTICE IMPLICATIONS: However, despite the lack of statistical significance, both physiological values and feeding performance tended to be better when the infants were fed in the ESL position, nurses can practice ESL position according to the infant's opposite direction of the side of the cleft lip or palate.

Characterization of heart rate variability in end-stage renal disease patients after kidney transplantation with recurrence quantification analysis.

Heart rate variability (HRV) is a noninvasive approach to studying the autonomic modulation of heart rate in experimental settings, such as active standing sympathetic stimulation. It is known that patients with end-stage renal disease during active standing have few changes in HRV dynamics, which are improved after hemodialysis. However, it is unknown whether the response to active standing is recovered after definitive treatment with kidney transplantation. This work aims to assess the change in HRV dynamics in the supine position and active standing through time and frequency-based metrics, as well as recurrence plot quantitative analysis (RQA). We studied HRV dynamics by obtaining 5-minute electrocardiographic recordings from kidney transplant recipients who underwent an active standing test. The mean duration of heartbeats and their standard deviation diminished in active standing, compared with the supine position. Also, the low-frequency component of HRV and the presence of diagonal and vertical structures in RQA were predominant. A larger estimated glomerular filtration rate was significantly correlated with broader HRV in the supine position and during active standing. The narrower HRV during active standing may indicate a sympathetic response to external stimuli, which is expected in a functional cardiovascular system, and may be influenced by renal function.

Speed of heart rate changes during postural provocations in children and adolescents.

Heart rate is under constant autonomic influence but the development of the influence in children is not fully understood. Continuous electrocardiograms were obtained in 1045 healthy school-age children (550 females) during postural provocations with body position changes between supine, sitting, standing, supine, standing, sitting and supine (in this order), 10 min in each position with position changes within 20 s. Heart rate was measured in each position and speed of heart rate changes between positions were assessed by regressions of rates versus timing of individual cardiac cycles. Supine heart rate was gradually decreasing with age: 82.32 ± 9.92, 74.33 ± 9.79, 67.43 ± 9.45 beats per minute (bpm) in tertile age groups < 11, 11-15, > 15 years, respectively (p < 0.0001), with no significant sex difference. Averaged speed of heart rate changes differed little between sexes and age groups but was significantly faster during rate deceleration than acceleration (e.g., supine ↔ standing: 2.99 ± 1.02 vs. 2.57 ± 0.68 bpm/s, p < 0.0001). The study suggests that in children, vagal heart rate control does not noticeably change between ages of approximately 6-19 years. The gradual resting heart rate decrease during childhood and adolescence is likely caused by lowering of cardiac sympathetic influence from sympathetic overdrive in small children to adult-like sympatho-vagal balance in older adolescents.

Exploration of postural effects on the external jugular and diploic venous system using upright computed tomography scanning.

PURPOSE: Few studies have investigated the influence of posture on the external jugular and diploic venous systems in the head and cranial region. In this study, we aimed to investigate the effects of posture on these systems using upright computed tomography (CT) scanning. METHODS: This study retrospectively analysed an upright CT dataset from a previous prospective study. In each patient, the diameters of the vessels in three external jugular tributaries and four diploic veins were measured using CT digital subtraction venography in both supine and sitting positions. RESULTS: Amongst the 20 cases in the original dataset, we eventually investigated 19 cases due to motion artifacts in 1 case. Compared with the supine position, most of the external jugular tributaries collapsed, and the average size significantly decreased in the sitting position (decreased by 22-49% on average). In contrast, most of the diploic veins, except the occipital diploic veins, tended to increase or remain unchanged (increased by 12-101% on average) in size in the sitting position compared with the supine position. However, the changes in the veins associated with this positional shift were not uniform; in approximately 5-30% of the cases, depending on each vein, an opposite trend was observed. CONCLUSION: Compared to the supine position, the contribution of external jugular tributaries to head venous drainage decreased in the sitting position, whilst most diploic veins maintained their contribution. These results could enhance our understanding of the physiology and pathophysiology of the head region in upright and sitting positions.

Parental Education for the Prevention of Plagiocephaly.

INTRODUCTION: The American Academy of Pediatrics Back-to-Sleep Campaign significantly reduced infant mortality from sudden infant death syndrome. As a result of prolonged supine positioning, the incidence of deformational plagiocephaly has also risen 5-fold since its adoption. We aimed to improve the current educational paradigm for new parents with the goal of reducing the incidence of plagiocephaly within the confines of the Back-to-Sleep Campaign. We hypothesized that the early addition of plagiocephaly focused education for parents would reduce cephalic index, the ratio of head width to length, used as an easily measured objective proxy for positional plagiocephaly. METHODS: Children were screened at their newborn visit. Premature newborns and those diagnosed with craniofacial disorders were excluded. For those enrolled, biparietal and anteroposterior measurements of the head were obtained using manual calipers to obtain cephalic index. Subjects randomly assigned to the intervention group were shown a 2-minute video and given an educational pamphlet on methods to prevent plagiocephaly. Unpaired 2-sample t tests comparing mean differences in intervention and control were performed. RESULTS: Thirty-nine subjects were enrolled as of November 2023 with variable lengths of follow-up completed. The average baseline cephalic index for subjects in the control group was 82.7 and 83.8 for intervention group. Unpaired 2-sample t tests were performed at 2-, 4-, and 6-month time points to analyze the difference between groups. At 4 months, average cephalic index for subjects in the control and treatment group, respectively, was 90.6 and 83.4 (P = 0.02). SIGNIFICANCE: Parental education at the newborn visit led to decreases in cephalic index, a proxy for positional plagiocephaly, compared with control patients. This simple intervention has the potential to reduce parental stress and healthcare costs associated with the evaluation and treatment of plagiocephaly.

[Discussion and analysis the value of supine median³ nystagmus in the diagnosis and treatment of HC-BPPV].

Objective:To explore the clinical value of supine median³ nystagmus in the accurate diagnosis of horizontal semicircular canal benign paroxysmal positional vertigo（HC-BPPV）. Methods:A total of 187 patients with HC-BPPV admitted to the First Affiliated Hospital of Xi'an Jiaotong University from June 2020 to March 2021 were selected. Among them 42 cases of Cupulolithiasis and 145 cases of Canalithiasis. The nystagmus parameters of patients left and right supine position and supine median³ position were recorded in detail by RART. According to the direction of supine median³ nystagmus, patients were divided into three groups: group A（nystagmus to weak side）, group B（nystagmus to strong side）, group C（negative nystagmus）. The canalith repositioning manoeuvres（CRM） was carried out by utility of an automatic vestibular function diagnosis and therapy system（SRM-IV）. The cure rate of CRM in three groups of HC-BPPV patients was compared, Multivariate logistic regression analysis was performed to analyze the influencing factors of CRM for HC-BPPV. Results:The cure rates of group A, group B and group C were 81.58%, 16.13% and 56.25%, respectively. The difference among the three groups was statistically significant. Then a pairwise comparison of group A, B and C, the difference was statistically significant（χ²A-B=40.294,P<0.001,χ²B-C=14.528, P<0.001,χ²A-C=11.606, P=0.001）; the results of multivariate logistic regression analysis showed that the direction of supine median³ nystagmus and BMI were the influencing factors of CRM for HC-BPPV. Conclusion:The direction, intensity and duration of supine median³ nystagmus play an important role in determining the responsibility semicircular canal of HC-BPPV.

Is intramedullary nailing of femoral diaphyseal fractures in the lateral decubitus position as safe and effective as on a traction table?

OBJECTIVES: The aim of this study was to compare the radiological and clinical results of femoral diaphyseal fractures operated in the lateral decubitus position with those operated in the supine position on a traction table and to detail the perioperative surgical technique. PATIENTS AND METHODS: Between October 2018 and January 2022, in this prospective, randomized, and single-blind comparative study, 75 patients diagnosed with adult femoral diaphyseal fractures to whom intramedullary nails were applied were operated in the lateral decubitus position without a traction table (Group 1, 37 patients) and in the supine position with a traction table (Group 2, 38 patients). Preoperative age, gender, fracture mechanism, fracture type, and surgical waiting times were determined. Perioperative anesthesia type, surgery preparation time, surgical time, number of fluoroscopy doses, amount of bleeding, and type of reduction were evaluated, and detailed observational descriptions of the surgical techniques were made. In the postoperative period, radiological evaluations were made with x-ray radiography and orthoroentgenogram, while in the clinical evaluation, hip-knee joint range of motion and rotational evaluation were made with the Craigs test. Follow-up periods were determined and complications noted. RESULTS: The average age was 32 in Group 1 and 28 in Group 2, the female/male ratio was 1:36 in Group 1 and 5:33 in Group 2, and the follow-up period was 18.2 months Group 1 and 21.7 months in Group 2. No significant difference was detected between the groups in terms of age, gender, fracture mechanism, fracture type, anesthesia type, surgical waiting time, and follow-up period (p > 0.05). Compared to Group 2, the shorter preparation time, surgical time, and number of fluoroscopy doses in Group 1 were found to be statistically significant (p < 0.05). The differences in the amount of bleeding and need for open reduction were not statistically significant between the groups (p > 0.05), and no statistical difference was found in joint range of motion and rotational evaluation in clinical evaluation in both groups (p > 0.05). There was no significant difference in terms of complications between groups. CONCLUSIONS: We found the lateral decubitus method without a traction table to be a safe and effective alternative to the supine method with a traction table in terms of the radiological and clinical results and that it also has the advantages of shortening the surgical time, reducing radiation exposure. LEVEL OF EVIDENCE: Level 1 prospective, randomized, single-blind controlled study.

Comparative analysis of ultrasound-guided percutaneous biopsy of native kidneys in children and adults using the free-flank supine antero-lateral decubitus positioning.

PURPOSE: Ultrasound-guided percutaneous biopsy (USPB) of the native kidneys is the preferred diagnostic method for several nephrological conditions in both adult and pediatric populations. Conventionally, native kidney biopsies are conducted with patients in the prone position (PP). However, an alternative approach involving the supine oblique antero-lateral position (SALP) has been explored, particularly for individuals who are obese, elderly, or critically ill. METHODS: This study aimed to assess the feasibility and outcomes of USPB performed in SALP with a Free-Flank setting (FF-SALP) in pediatric patients (Group A) compared to adults (Group B). Data from kidney biopsies conducted between 2008 and 2021 were gathered. The study focused on the safety and the prevalence of biopsy samples containing a minimum of 10 glomeruli, histopathological yield in both groups. RESULTS: Complication rates were low in both groups (5.6% vs. 3.7%; p = 0.454), without major complications noted. The pediatric group achieved a significantly higher mean number of glomeruli per biopsy compared to the adult group (20.6 ± 12.3 vs. 15.7 ± 9.4; p < 0.001). However, when evaluating the minimum threshold of 10 glomeruli (76.3% vs. 68.5%; p = 0.072) and histopathologic yield (95.3% vs. 93.5%; p = 0.408), no differences were observed between groups. CONCLUSION: USPB of native kidneys in the FF-SALP position is a safe and effective method for tissue sampling in patients with parenchymal disease. It demonstrated comparable diagnostic yields and complication rates in the pediatric and adult populations, providing advantages in terms of airway management, making it particularly useful for pediatric patients that require general anesthesia.

Impact of posture and CPAP on nasal airflow.

Obstructive sleep apnea (OSA) patients who use continuous positive airway pressure (CPAP) often complain of nasal dryness and nasal obstruction as side effects of CPAP. The physiological mechanisms by which CPAP may cause nasal dryness and nasal obstruction remain poorly understood. It has been hypothesized that CPAP interferes with the nasal cycle, abolishing the resting phase of the cycle and leading to nasal dryness. We performed rhinomanometry measurements in 31 OSA patients sitting, laid supine, and supine after 10 min of CPAP at 10 cmH2O. A posture change from sitting to supine led to more symmetric airflow partitioning between the left and right nostrils in the supine position. CPAP did not have a significant impact on nasal resistance, unilateral airflows, or airflow partitioning. Our results suggest that airflow partitioning becomes more symmetric immediately after changing to a supine position, while CPAP had no effect on nasal airflow, thus preserving the nearly symmetric airflow partitioning achieved after the posture change.

Response to Hypoglossal Nerve Stimulation Changes With Body Mass Index and Supine Sleep.

Importance: Hypoglossal nerve stimulation (HGNS) is a potential alternative therapy for obstructive sleep apnea (OSA), but its efficacy in a clinical setting and the impact of body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) on treatment response remain unclear. Objective: To investigate whether HGNS therapy is effective for patients with OSA, whether HGNS can treat supine OSA, and whether there are associations between BMI and treatment response. Design, Setting, and Participants: In this cohort study, adult patients with OSA implanted with HGNS at the Washington University Medical Center in St Louis from April 2019 to January 2023 were included. Data were analyzed from January 2023 to January 2024. Exposure: HGNS. Main Outcomes and Measures: Multivariable logistic regression was performed to assess associations between HGNS treatment response and both BMI and supine sleep. Treatment response was defined as 50% reduction or greater in preimplantation Apnea-Hypopnea Index (AHI) score and postimplantation AHI of less than 15 events per hour. Results: Of 76 included patients, 57 (75%) were male, and the median (IQR) age was 61 (51-68) years. A total of 59 patients (78%) achieved a treatment response. There was a clinically meaningful reduction in median (IQR) AHI, from 29.3 (23.1-42.8) events per hour preimplantation to 5.3 (2.6-12.3) events per hour postimplantation (Hodges-Lehman difference of 23.0; 95% CI, 22.6-23.4). In adjusted analyses, patients with BMI of 32 to 35 had 75% lower odds of responding to HGNS compared with those with a BMI of 32 or less (odds ratio, 0.25; 95% CI, 0.07-0.94). Of 44 patients who slept in a supine position, 17 (39%) achieved a treatment response, with a clinically meaningful reduction in median (IQR) supine AHI from 46.3 (33.6-63.2) events per hour preimplantation to 21.8 (4.30-42.6) events per hour postimplantation (Hodges-Lehman difference of 24.6; 95% CI, 23.1-26.5). In adjusted analysis, BMI was associated with lower odds of responding to HGNS with supine AHI treatment response (odds ratio, 0.39; 95% CI, 0.04-2.59), but the imprecision of the estimate prevents making a definitive conclusion. Conclusions and Relevance: This study adds to the growing body of literature supporting the use of HGNS for OSA treatment. Sleep medicine clinicians should consider informing patients that higher BMI and supine sleeping position may decrease therapeutic response to HGNS. Future research is needed to replicate these findings in larger, more diverse cohorts, which would facilitate the optimization of treatment strategies and patient counseling for HGNS therapy.

The Tension Between AAP Safe Sleep Guidelines and Infant Sleep.

OBJECTIVES: To understand tension mothers experience when attempting to follow American Academy of Pediatrics safe sleep guidelines and enhancing infant and parental sleep. METHODS: Surveys and focus groups were conducted from November 2022 and March 2023 with United States-based English-speaking mothers of infants <6 months of age recruited via social media and who reported a nonrecommended sleep position and/or location ≥2 times the prior week. RESULTS: Twenty-five mothers participated in focus groups and surveys. A total of 80% reported holding or rocking their infant to sleep; 76% fed their infant to sleep. Almost all were aware of the ABCs (Alone, Back, Crib) of safe sleep and intended to follow them before delivery. Many felt that ABCs were unrealistic and placed their infants in nonrecommended locations or positions because they perceived them as more comfortable and helping their infant fall and stay asleep. Mothers were more likely to use nonrecommended practices when they were awake or sleeping nearby and believed they could closely monitor their infant. Some questioned whether ABCs were the only way to achieve safe sleep. Some prioritized other safety concerns (eg, fall prevention) over sudden infant death syndrome or sudden unexpected infant death prevention. Mothers expressed confidence about getting their baby to sleep in general but were less confident that they could do this while following guidelines. CONCLUSIONS: Despite awareness of the ABCs, mothers regularly engaged in nonrecommended practices with the goal of improving their own and their infant's sleep. Interventions focused on improving infant and parental sleep while maintaining sleep safety are needed.

Is supine a preferred position for percutaneous nephrolithotomy in the pediatric age group? A randomized controlled study.

BACKGROUND: The aim is to evaluate supine versus prone position in mini-percutaneous nephrolithotomy in pediatric renal urolithiasis management. METHODS: A randomized controlled trial was constructed to evaluate supine versus prone position in pediatric PCNL. Seventy pediatric patients with a stone burden ≥1.5 cm were randomized into two groups. RESULTS: Sixty-three patients were available for evaluation in our study with no significant difference in the perioperative demographic data. The supine group showed a shorter operation time of 43.9 min compared to 73.5 min in the prone group. The stone-free rate was higher in the supine group, with a 93.9% SFR compared to 83.3% in the prone group. The supine group showed a shorter hospital stay of 2.0±1.0 days, compared to 3.20±1.56 days in the prone group. No significant difference was seen in the perioperative complication rate and fluoroscopy time between both groups. CONCLUSIONS: Supine mini-percutaneous nephrolithotomy is safe and effective in managing pediatric renal stones, with a higher stone-free rate, less operative time, and less hospital stay compared to the prone position.

Jugular venous flow dynamics during acute weightlessness.

During spaceflight, fluids shift headward, causing internal jugular vein (IJV) distension and altered hemodynamics, including stasis and retrograde flow, that may increase the risk of thrombosis. This study's purpose was to determine the effects of acute exposure to weightlessness (0-G) on IJV dimensions and flow dynamics. We used two-dimensional (2-D) ultrasound to measure IJV cross-sectional area (CSA) and Doppler ultrasound to characterize venous blood flow patterns in the right and left IJV in 13 healthy participants (6 females) while 1) seated and supine on the ground, 2) supine during 0-G parabolic flight, and 3) supine during level flight (at 1-G). On Earth, in 1-G, moving from seated to supine posture increased CSA in both left (+62 [95% CI: +42 to 81] mm2, P < 0.0001) and right (+86 [95% CI: +58 to 113] mm2, P < 0.00012) IJV. Entry into 0-G further increased IJV CSA in both left (+27 [95% CI: +5 to 48] mm2, P = 0.02) and right (+30 [95% CI: +0.3 to 61] mm2, P = 0.02) relative to supine in 1-G. We observed stagnant flow in the left IJV of one participant during 0-G parabolic flight that remained during level flight but was not present during any imaging during preflight measures in the seated or supine postures; normal venous flow patterns were observed in the right IJV during all conditions in all participants. Alterations to cerebral outflow dynamics in the left IJV can occur during acute exposure to weightlessness and thus, may increase the risk of venous thrombosis during any duration of spaceflight.NEW & NOTEWORTHY The absence of hydrostatic pressure gradients in the vascular system and loss of tissue weight during weightlessness results in altered flow dynamics in the left internal jugular vein in some astronauts that may contribute to an increased risk of thromboembolism during spaceflight. Here, we report that the internal jugular veins distend bilaterally in healthy participants and that flow stasis can occur in the left internal jugular vein during acute weightlessness produced by parabolic flight.

Opioid-free anesthesia with ultrasound-guided quadratus lumborum block in the supine position for lower abdominal or pelvic surgery: a randomized controlled trial.

In the past, quadratus lumborum block (QLB) was mostly used for postoperative analgesia in patients, and few anesthesiologists applied it during surgery with opioid-free anesthesia (OFA). Consequently, it is still unclear whether QLB in the supine position can provide perfect analgesia and inhibit anesthetic stress during surgery under the OFA strategy. To observe the clinical efficacy of ultrasound-guided quadratus lumborum block (US-QLB) in the supine position with OFA for lower abdominal and pelvic surgery. A total of 122 patients who underwent lower abdominal or pelvic surgery in People's Hospital of Wanning between March 2021 and July 2022 were selected and divided into a quadratus lumborum block group (Q) (n = 62) and control group (C) (n = 60) according to the random number table method. Both groups underwent general anesthesia combined with QLB in the supine position. After sedation, unilateral or bilateral QLB was performed via the ultrasound guided anterior approach based on images resembling a "human eye" and "baby in a cradle" under local anesthesia according to the needs of the operative field. In group Q, 20 ml of 0.50% lidocaine and 0.20% ropivacaine diluted in normal saline (NS) were injected into each side. In group C, 20 ml of NS was injected into each side. The values of BP, HR, SPO2, SE, RE, SPI, NRS, Steward score, dosage of propofol, dexmedetomidine, and rocuronium, the number of patients who needed remifentanil, propofol, or diltiazem, puncture point, block plane, duration of anesthesia, catheter extraction, and wakefulness during the operation were monitored. There were no significant differences in the general data, number of cases requiring additional remifentanil, propofol, or diltiazem treatment, as well as puncture point and puncture plane between the two groups (P > 0.05). HR, SBP, and DBP values were higher in group Q than in group C at T1; HR, SPI, and SE, while RE values were lower in group Q than in group C at T3, SE, and RE; the Steward score was higher in group Q than in group C at T4 and T5, and the difference was statistically significant (P < 0.05). The extubation and awake times were lower in group Q than in group C, and the difference was statistically significant (P < 0.05). The SE, RE, and SPI values were lower at T1, T2, T3, and T4 than at T0. The Steward scores at T4 and T5 were higher in group Q than in group C, and were lower than at T0, with a statistically significant difference (P < 0.05). There were significant differences in the effectiveness of postoperative analgesia between the two groups at t1, t3 and t4 (P < 0.05). US-QLB in the supine position with OFA is effective in patients undergoing lower abdominal or pelvic surgery with stable intraoperative vital signs, complete recovery and better postoperative analgesia.