The Trendelenburg position and reverse Trendelenburg position are frequently employed during lower abdominal surgery to achieve optimal surgical field visualization and complete exposure of the operative site, particularly under pneumoperitoneum conditions. However, these positions can have significant impacts on the patient's physiological functions. This article overviews the historical background of Trendelenburg position and reverse Trendelenbury position, their effects on various physiological functions, recent advancements in their clinical applications, and strategies for preventing and managing associated complications.
Humans ; Head-Down Tilt/physiology* ; Patient Positioning ; Abdomen ; Laparoscopy

BACKGROUND: Elevated intracranial pressure (ICP), a disadvantage of laparoscopic or robotic surgery, is caused by the steep angle of the Trendelenburg position and the CO₂ pneumoperitoneum. Recently, sonographically measured optic nerve sheath diameter (ONSD) was suggested as a simple and non-invasive method for detecting increased ICP. This study aimed to explore the changes in ONSD in relation to different anesthetic agents used in gynecologic surgery.METHODS: Fifty patients were randomly allocated to two groups, sevoflurane (group SEV, n = 25) and propofol-based total intravenous anesthesia (TIVA) group (group TIVA, n = 25). The ONSD was measured at five time points (T0–T4): T0 was measured 5 min after induction of anesthesia in the supine position; T1, T2, and T3 were measured at 5, 15, and 30 min after CO₂ pneumoperitoneum induction in the Trendelenburg position; and T4 was measured at 5 min after discontinuation of CO₂ pneumoperitoneum in the supine position. Respiratory and hemodynamic variables were also recorded.RESULTS: The intra-group changes in mean ONSD in the Trendelenburg position were significantly increased in both groups. However, inter-group changes in mean ONSD were not significantly different at T0, T1, T2, T3, and T4. Heart rates in group TIVA were significantly lower than those in group SEV at points T1–T4.CONCLUSIONS: There was no significant difference in the ONSD between the two groups until 30 min into the gynecologic surgery with CO₂ pneumoperitoneum in the Trendelenburg position. This study suggests that there is no difference in the ONSD between the two anesthetic methods.
Anesthesia ; Anesthesia, Intravenous ; Anesthetics ; Female ; Gynecologic Surgical Procedures ; Head-Down Tilt ; Heart Rate ; Hemodynamics ; Humans ; Intracranial Hypertension ; Methods ; Optic Nerve ; Pneumoperitoneum ; Propofol ; Supine Position ; Ultrasonography

OBJECTIVE: To evaluate the effectiveness of the pulmonary recruitment maneuver (PRM) at the end of the operation to decrease laparoscopy-induced abdominal or shoulder pain after gynecological oncologic surgery. METHODS: In total, 113 women undergoing laparoscopic surgery for malignant or premalignant gynecological lesions were assigned randomly to two groups: the PRM group (the patient was placed in the Trendelenburg position (30°) and the PRM, consisting of two manual pulmonary inflations to a maximum pressure of 40 cmH2O) (n=54) and the control group (n=52). Postoperative shoulder and abdominal pain was assessed 12, 24, and 48 hours later using a visual analog scale (0–10). In addition, the incidence of post-discharge nausea and vomiting was recorded until 48 hours after discharge. RESULTS: Postoperative shoulder pain at 12 and 24 hours was significantly less severe in the PRM group (2.2±0.5 and 2.0±0.4) than in the control group (4.0±0.5 and 3.9±0.4; both p < 0.001). The PRM significantly reduced the severity of upper abdominal pain at 12 and 24 h compared with the control group (3.1±0.4 and 2.9±0.4 vs. 5.9±0.5 and 4.9±0.5; both p < 0.001). The analgesic requirement during the postoperative period was similar in the two groups (control group, 78.8%; PRM group, 75.9%; p=0.719). CONCLUSION: The PRM effectively and safely reduced postoperative shoulder and upper abdominal pain levels in patients undergoing laparoscopic gynecological oncologic surgery. Trial registry at ClinicalTrials.gov, NCT01940042.
Abdominal Pain ; Female ; Head-Down Tilt ; Humans ; Incidence ; Laparoscopy ; Nausea ; Postoperative Period ; Prospective Studies* ; Shoulder ; Shoulder Pain ; Visual Analog Scale ; Vomiting

BACKGROUNDFew studies have focused on peripheral nerve conduction during exposure to microgravity. The -6° head-down tilt (HDT) comprises an experimental model used to simulate the space flight environment. This study investigated nerve conduction characteristics of rhesus monkeys before and after prolonged exposure to HDT.

METHODSSix rhesus monkeys (3-4 years old) were tilted backward 6° from the horizontal. Nerve conduction studies (NCSs) were performed on the median, ulnar, tibial, and fibular motor nerves. Analysis of variance with a randomized block design was conducted to compare the differences in the NCS before and 7, 21, and 42 days after the -6° HDT.

RESULTSThe proximal amplitude of the CMAP of the median nerve was significantly decreased at 21 and 42 days of HDT compared with the amplitude before HDT (4.38 ± 2.83 vs. 8.40 ± 2.66 mV, F = 4.85, P = 0.013 and 3.30 ± 2.70 vs. 8.40 ± 2.66 mV, F = 5.93, P = 0.004, respectively). The distal amplitude of the CMAP of the median nerve was significantly decreased at 7, 21, and 42 days of HDT compared with the amplitude before HDT (7.28 ± 1.27 vs. 10.25 ± 3.40 mV, F = 4.03, P = 0.039; 5.05 ± 2.01 vs. 10.25 ± 3.40 mV, F = 6.25, P = 0.04; and 3.95 ± 2.79 vs. 10.25 ± 3.40 mV, F = 7.35, P = 0.01; respectively). The proximal amplitude of the CMAP of the tibial nerve was significantly decreased at 42 days of HDT compared with the amplitude before HDT (6.14 ± 1.94 vs. 11.87 ± 3.19 mV, F = 5.02, P = 0.039).

CONCLUSIONSThis study demonstrates that the compound muscle action potential amplitudes of nerves are decreased under simulated microgravity in rhesus monkeys. Moreover, rhesus monkeys exposed to HDT might be served as an experimental model for the study of NCS under microgravity.

Action Potentials ; physiology ; Animals ; Female ; Head-Down Tilt ; physiology ; Macaca mulatta ; Male ; Neural Conduction ; physiology ; Weightlessness Simulation

BACKGROUND: This randomized, controlled study was designed to compare the effects of recruitment maneuvers (RMs) with a 15 cmH₂O positive end-expiratory pressure (PEEP) on the systemic oxygenation and lung compliance of patients with healthy lungs following robot-assisted laparoscopic prostatectomy (RALP). METHODS: Sixty patients undergoing a RALP with an intraoperative 15 cmH₂O PEEP were randomly allocated to an RM or a Control group. The patients in the RM group received a single RM through the application of a continuous positive airway pressure of 40 cmH₂O for 40 s 15 min after being placed in the Trendelenburg position. The arterial oxygen tension (PaO₂, primary endpoint) and the pulmonary dynamic and static compliances (secondary endpoints) were measured 10 min after the anesthetic induction (T1), 10 min after establishment of the pneumoperitoneum (T2), 10 min after establishment of the Trendelenburg position (T3), 10 min after the RM (T4), 60 min after the RM (T5), and 10 min after deflation of the pneumoperitoneum in the supine position (T6). RESULTS: The intergroup comparisons of the PaO₂ showed significantly higher values in the RM group than in the Control group at T4 and T5 (193 ± 35 mmHg vs. 219 ± 33 mmHg, P = 0.015, 188 ± 41 mmHg vs. 214 ± 42 mmHg, P = 0.005, respectively). However, the PaO₂ at T6 was similar in the two groups (211 ± 39 mmHg vs. 224 ± 41 mmHg, P = 0.442). Moreover, there were no statistical differences between the groups in the dynamic and static compliances of the lungs at any time point. CONCLUSIONS: The arterial oxygenation of the patients with a healthy lung function who had undergone a RALP with intraoperative 15 cmH₂O PEEP was improved by a single RM. However, this benefit did not last long, and it did not lead to an amelioration of the lung mechanics.
Continuous Positive Airway Pressure ; Head-Down Tilt ; Humans ; Lung ; Lung Compliance ; Mechanics ; Oxygen* ; Pneumoperitoneum ; Positive-Pressure Respiration* ; Prostatectomy* ; Supine Position

Increased intraocular pressure (IOP) during surgery is a risk factor for postoperative ophthalmological complications. We assessed the efficacy of systemically infused dexmedetomidine in preventing the increase in IOP caused by a steep Trendelenburg position, and evaluated the influence of underlying hypertension on IOP during surgery. Sixty patients undergoing laparoscopic surgery in a steep Trendelenburg position were included. Patients in the dexmedetomidine group received a 1.0 µg/kg IV loading dose of dexmedetomidine before anesthesia, followed by an infusion of 0.5 µg/kg/hr throughout the operation. Patients in the saline group were infused with the same volume of normal saline. IOP and ocular perfusion pressure (OPP) were measured 16 times pre- and intraoperatively. In the saline group, IOP increased in the steep Trendelenburg position, and was 11.3 mmHg higher at the end of the time at the position compared with the baseline value (before anesthetic induction). This increase in IOP was attenuated in the dexmedetomidine group, for which IOP was only 4.2 mmHg higher (P < 0.001 vs. the saline group). The steep Trendelenburg position was associated with a decrease in OPP; the degree of decrease was comparable for both groups. In intragroup comparisons between patients with underlying hypertension and normotensive patients, the values of IOP at every time point were comparable. Dexmedetomidine infusion attenuated the increase in IOP during laparoscopic surgery in a steep Trendelenburg position, without further decreasing the OPP. Systemic hypertension did not seem to be associated with any additional increase in IOP during surgery. (Registration at the Clinical Research Information Service of Korea National Institute of Health ID: KCT0001482)
Aged ; Dexmedetomidine/administration & dosage/*pharmacology ; Double-Blind Method ; Eye Diseases/surgery ; Female ; Head-Down Tilt ; Humans ; Hypnotics and Sedatives/administration & dosage/pharmacology ; Intraocular Pressure/*drug effects ; Intraoperative Complications/drug therapy/prevention & control ; Laparoscopy ; Male ; Middle Aged ; Prospective Studies ; Risk Factors ; Tonometry, Ocular ; Treatment Outcome

Pseudo-Meigs syndrome is accompanied with pleural effusion, ascites and a benign or malignant tumor of ovary, tubes, uterus, round ligament or colon. We reported a case of hypoxia in an ovarian cancer patient with moderate ascites after head-down tilt position for central venous catheterization under general anesthesia. Massive pleural effusion was detected on portable chest X-ray, which was not observed in a preoperative radiologic test. The patient had no respiratory symptoms and breath sound was normal in both lungs prior to surgery. The pleural effusion was resolved by a chest tube insertion.
Anesthesia, General ; Anoxia ; Ascites* ; Catheterization, Central Venous ; Central Venous Catheters ; Chest Tubes ; Colon ; Female ; Head-Down Tilt* ; Humans ; Lung ; Ovarian Neoplasms* ; Ovary ; Pleural Effusion* ; Round Ligament of Uterus ; Thorax ; Uterus

BACKGROUND: Laparoscopic gastrectomy requires a reverse-Trendelenburg position and prolonged pneumoperitoneum and it could cause significant changes in cerebral homeostasis and lead to cognitive dysfunction. We compared changes in regional cerebral oxygen saturation (rSO2), early postoperative cognitive function and hemodynamic variables in patients undergoing laparoscopic gastrectomy with those patients that underwent conventional open gastrectomy. METHODS: Sixty patients were enrolled in this study and the patients were distributed to receive either laparoscopic gastrectomy (laparoscopy group, n = 30) or open conventional gastrectomy (open group, n = 30). rSO2, end-tidal carbon dioxide tension, hemodynamic variables and arterial blood gas analysis were monitored during the operation. The enrolled patients underwent the mini-mental state examination 1 day before and 5 days after surgery for evaluation of early postoperative cognitive function. RESULTS: Compared to baseline value, rSO2 and end-tidal carbon dioxide tension increased significantly in the laparoscopy group after pneumoperitoneum, whereas no change was observed in the open group. No patient experienced cerebral oxygen desaturation or postoperative cognitive dysfunction. Changes in mean arterial pressure over time were significantly different between the groups (P < 0.001). CONCLUSIONS: Both laparoscopic and open gastrectomy did not induce cerebral desaturation or early postoperative cognitive dysfunction in patients under desflurane anesthesia. However, rSO2 values during surgery favoured laparoscopic surgery, which was possibly related to increased cerebral blood flow due to increased carbon dioxide tension and the effect of a reverse Trendelenburg position.
Anesthesia ; Arterial Pressure ; Blood Gas Analysis ; Carbon Dioxide ; Gastrectomy* ; Head-Down Tilt ; Hemodynamics ; Homeostasis ; Humans ; Laparoscopy ; Oxygen* ; Pneumoperitoneum

Perioperative stroke can lead to mortality or serious disability and usually occurs in patients undergoing cardiac, vascular, or neurologic surgery; it is rare in gynecological surgery. We report the case of a patient who suffered life-threatening cerebral infarction after elective laparoscopic hysterectomy. During the surgery, the patient was placed in the Trendelenburg position. On postoperative day one, the patient was diagnosed with right hemisphere cerebral infarction; brain computed tomographic angiography showed proximal right internal carotid artery occlusion. Decompressive craniectomy was performed to resolve brain swelling, but the patient died 10 days later.
Angiography ; Brain ; Brain Edema ; Carotid Artery, Internal ; Cerebral Infarction* ; Decompressive Craniectomy ; Female ; Gynecologic Surgical Procedures ; Head-Down Tilt* ; Humans ; Hysterectomy* ; Mortality ; Stroke

OBJECTIVETo observe the effect of carbon dioxide pneumoperitoneum and Trendelenburg position on cerebral blood backflow during robot-assisted radical prostatectomy in elderly patients.

METHODSFifty elderly patients (65-80 years) and 50 middle-aged patients (45-64 years) undergoing elective robot-assisted prostatectomy were enrolled in this study. For all the patients, jugular bulb and arterial blood gas was monitored and recorded before pneumoperitoneum (0), 10 min after pneumoperitoneum was achieved (T₁), 10 min (T₂) and 60 min (3) after Trendelenberg position, and 10 min in supine position after termination of pneumoperitoneum (4).

RESULTSCompared with those at 0, the mean arterial pressure, heart rate, and BIS value at 1, 2, 3 and 4 all showed no significant variations (P>0.05), but rSO2, SjvO2, and JBP increased significantly in both groups (P<0.01). Compared with those in the middle-aged group, rSO₂, SjvO₂, and JBP increased significantly and Da-jO₂decreased at 2, 3 in the elderly group (P<0.01), but jugular vein blood glucose or lactic acid content showed no significant difference between the two groups (P>0.05).

CONCLUSIONPneumoperitoneum and Trendelenburg position cause more obvious cerebral blood backflow in elderly patients than in middle-aged patients but do not affect cerebral metabolism of oxygen.

Aged ; Aged, 80 and over ; Brain ; blood supply ; Carbon Dioxide ; Head-Down Tilt ; Heart Rate ; Humans ; Jugular Veins ; Male ; Middle Aged ; Monitoring, Physiologic ; Oxygen ; Pneumoperitoneum, Artificial ; Prostate ; surgery ; Prostatectomy ; methods ; Robotic Surgical Procedures ; methods