Background:Hypovolemia is a common cause of hypotension and low cardiac index (CI) in cardiac surgery but no hemodynamic parameters reflect this status well. The accurate diagnosis of hypovolemia is important because the wrong treatment will cause ineffectiveness and bad consequences such as severe heart failure, pulmonary edema, ... Objectives: To evaluate the performance of diagnostic characteristics of the trendelenburg 300 test for hypovolemia in cardiac surgery. Subjects and method: The prospective, cross \ufffd?sectional and randomized controlled trial (RCT) study was conducted on 30 patients (18 males, 12 females and average age 47,17 \xb1 13,93) undergoing valvular repair/replacement or coronary revascularization. The Swan \ufffd?Ganz catheters were placed in 20 patients and PiCCO catheters in 10 patients. Trendelenburg 300 test is considered positive if blood pressure (BP), central venous pressure (CVP), CI and intrathoracic blood volume (ITBV) increase. Results: The hypovolemic status in cardiac surgical patients is diagnosed if BP and/or CI increase in trendelenburg 300 position (Se 87.5% and 65.63%; Sp 100% and 75%, area under ROC 0.83 and 0.81, respectively). Conclusion: The increases in BP and CI responding to trendelenburg 300 position are good indicators of hypovolemia in cardiac surgery.
Hypovolemia/ diagnosis ; Head-Down Tilt ; Thoracic Surgery ;

The effect of anesthetic volume on the spread of hypobaric tetracaine were sutdied after intrathecal injection in thirty patients with prone jackknife and 15 degree Trendelenburg position for perinal surgery. The patients were assigned randomly into the one of three groups divided by the 3, 4, or 5 ml of volume of anesthetic solution. The results show that the volume of tetracaine in distilled water with hypobaric spinal anesthesia in prone jackknife and l5 degree Trendelenburg position had a important effect on the anesthetic dermatomal levels in spite of slightly rapid onset with large. volume. Therefore, we concluded that for the perianal surgery in prone jackknife position, as the volume of the anes- thetic solution with hypobaric spinal anesthesia, 3 or 4 ml of the volume are sufficient to get the adequate anesthetic levels.
Anesthesia, Spinal* ; Head-Down Tilt ; Humans ; Injections, Spinal ; Tetracaine ; Water

BACKGROUND: It is known that pneumoperitoneum and changes of body position during laparoscopic surgery influenced peak inspiratory pressure (PIP). We asked the question whether oropharyngeal leak pressure (OLP) is changed by changes in intraabdominal pressure and position during laparoscopic surgery with a ProSeal laryngeal mask airway (PLMA). Since gynecological laparoscopic surgery (Lap-Gy) and laparoscopic cholecystectomy (Lap-C) require different surgical positions, we included both surgeries in this study so that we could investigate the effects of various positions on OLP. METHODS: Lap-Gy (n = 15) was performed in the trendelenburg position combined with the lithotomy position, whereas Lap-C (n = 10) was performed in the reverse trendelenburg position. The measured variables were PIP and OLP. We also marked the fiberoptic score to determine the intraoral position (FP) of the PLMA. OLP was measured using a manometric stability test. The variables were measured in a regular sequence as follows: S-0o-0, L-0o-0, L-0o-15, L-(-15o)-15, L-(-30o)-15 in Lap-Gy and S-0o-0, S-0o-15, S-(+15o)-15, S-(+30o)-15 in Lap-C. At each measured point, the capital S means supine and L lithotomy. Intermediate numbers with a 'o' superscript are table angles to the horizontal plane (degrees) , '-' means the trendelenburg position and '+', the reverse trendelenburg position, and the last number represents intraabdominal pressure (mmHg). RESULTS: PIP was significantly increased when L-0o-0 changed to L-0o-15, L-0o-15 to L-(-15o)-15 and L-(-15o)-15 to L-(-30o)-15 in Lap-G, and when S-0o-0 was changed to S-0o-15 in Lap-C (P < 0.05). But, OLP and FP were not significantly altered by changes in postion or intraabdominal pressure in both Lap-Gy and Lap-C. CONCLUSIONS: PIP was affected by pneumoperitoneum and positional changes. But, increases in intraabdominal pressure by pneumoperitoneum and changes in position during laparoscopic surgery had no effect on OLP and FP of PLMA.
Cholecystectomy, Laparoscopic ; Head-Down Tilt ; Laparoscopy* ; Laryngeal Masks* ; Pneumoperitoneum

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: Pneumoperitoneum and head-down tilt during a laparoscopic hysterectomy causes significant alterations in the hemodynamics including decreased cardiac output. The aim of this study was to evaluate the effects of a crystalloid preload on the hemodynamics after a hysterectomy (LAVH). METHODS: The patients were randomized to receive either no crystalloid fluid preload (control group: 29 women) or 10 ml/kg of a crystalloid fluid preload over 10 min (preloading group: 30 women) before the pneumoperitoneum. The hemodynamic parameters were measured before inducing anesthesia, immediately after the tracheal intubation, before the skin incision, and 2, 5, 10, 20, and 30 min after the pneumoperitoneum with CO2 with noninvasive cardiac output measurements using the partial CO2 rebreathing method. RESULTS: The cardiac index (CI) was reduced 2 and 5 min after the pneumoperitoneum, and then returned to normal. There were no significant differences in the CI after the pneumoperitoneum between the two groups (P<0.05). CONCLUSIONS: The administration of a 10 ml/kg crystalloid preload did not attenuate the decrease in the CI after pneumoperitoneum.
Anesthesia ; Cardiac Output ; Female ; Head-Down Tilt ; Hemodynamics* ; Humans ; Hysterectomy ; Hysterectomy, Vaginal* ; Intubation ; Pneumoperitoneum* ; Skin

BACKGROUND: Unlike the right internal jugular vein (RIJV), there is a paucity of data regarding the effect of the Trendelenburg position on the left internal jugular vein (LIJV). The purpose of this study is to investigate the cross-sectional area (CSA) of the LIJV and RIJV and their response to the Trendelenburg position using two-dimensional ultrasound in adult subjects. METHODS: This study enrolled fifty-eight patients with American Society of Anesthesiologists physical status class I-II who were undergoing general anesthesia. CSAs of both the RIJV and LIJV were measured with a two-dimensional ultrasound in the supine position and then in a 10degrees Trendelenburg position. RESULTS: In the supine position, the transverse diameter, anteroposterior diameter, and CSA of the RIJV were significantly larger than those of the LIJV (P < 0.001). Of 58 patients, the RIJV CSA was larger than the LIJV CSA in 43 patients (74.1%), and the LIJV CSA was larger than the RIJV CSA in 15 patients (25.9%). In the Trendelenburg position, CSAs of the RIJV and LIJV increased 39.4 and 25.5%, respectively, compared with the supine position. However, RIJV changed at a rate that was significantly greater than that of the LIJV (P < 0.05). Of 58 patients, the RIJV CSA was larger than the LIJV CSA in 48 patients (82.8%), and the LIJV CSA was larger than the RIJV CSA in 10 patients (17.2%). CONCLUSIONS: In supine position, the RIJV CSA was larger than the LIJV CSA. The increased CSA in the Trendelenburg position was greater in the RIJV than the LIJV.
Adult ; Anesthesia, General ; Central Venous Catheters ; Head-Down Tilt* ; Humans ; Jugular Veins* ; Supine Position ; Ultrasonography

BACKGROUND: The laparoscopy requires carbon dioxide (CO2) insufflation and Trendelenburg position for operational convenience. However, the above circumstances affect the cardiopulmonary systems significantly and intraocular pressure (IOP) may be also influenced. METHODS: In 27 non-glaucoma patients right and left intraocular pressure (RIOP, LIOP) were measured 5 minutes after induction of general anesthesia (control value), 15 and 30 minutes after CO2 insufflation and endelenburg-lithotomy position. RESULTS: The control values of RIOP and LIOP were 11.3 4.7 mmHg and 11.5 4.7 mmHg respectively. At 15 minutes after CO2 insufflation and Trendelenburg-lithotomy position, they increased to 16.6 5.3 mmHg and 17.0 5.9 mmHg (p<0.05). At 30 minutes, 18.4 3.5 mmHg and 18.2 4.1 mmHg (p<0.05). CONCLUSION: CO2 insufflation and Trendelenburg-lithotomy position increase IOP significantly in non-glaucoma patients during laparoscopy.
Anesthesia, General ; Carbon Dioxide ; Head-Down Tilt ; Humans ; Insufflation* ; Intraocular Pressure* ; Laparoscopy*

BACKGROUND: It has been reported that spinal anesthesia has a sedative effect and so this decreases the hypnotic requirement of intravenous anesthetic. Therefore, we have conducted a prospective randomized study to investigate the effect of the spinal anesthesia level on the hypnotic requirements for conscious sedation. METHODS: Forty adult patients were scheduled to undergo spinal anesthesia, and they were randomly allocated to one of the two groups. After subarachnoid injection of 0.5% hyperbaric bupivacaine 16 mg, the patients in group 1 and group 2 were maintained in a reversed Trendelenburg position and a Trendelenburg position, respectively. After fifteen minutes, the target controlled infusion of propofol was started for achieving a target concentration of 1 microgram/ml, and the mean BIS for 1 min was checked after an effect site concentration (Ce) of 1 microgram/ml was reached. The target controlled infusion of propofol was restarted at a target concentration (Tc) of 1.5 microgram/ml, and the mean BIS for 1 min was checked after the Ce level of 1.5 microgram/ml was reached. RESULTS: The mean BIS at 1 microgram/ml Ce was 90.0 +/- 8.5 and 77.8 +/- 10.3 in group 1 and group 2, respectively. The mean BIS at 1.5 g/ml Ce was 73.6 +/- 19.4 and 60.0 +/- 13.1, respectively. CONCLUSIONS: There was a significant difference in the requirements of propofol for conscious sedation between the below T12 block group and the above T4 block group.
Adult ; Anesthesia, Spinal ; Bupivacaine ; Conscious Sedation ; Head-Down Tilt ; Humans ; Hypnosis ; Hypnotics and Sedatives ; Propofol* ; Prospective Studies

PURPOSE: This study was carried out to evaluate the postural intraocular pressure (IOP) change in Trendelenburg, reverse Trendelenburg, and supine positions in healthy young males. METHODS: We measured the IOP values of 5 healthy young male volunteers (10 eyes) using an Icare PRO rebound tonometer in sitting, Trendelenburg, reverse Trendelenburg, and supine positions. RESULTS: The mean IOP in the supine position (18.63 mm Hg) was significantly higher (p < 0.01) than in the sitting position (15.31 mm Hg). When maintaining the Trendelenburg position, IOP gradually increased. CONCLUSIONS: In our study, the Trendelenburg position significantly increased the IOP compared to that in the supine position. The effects of increased IOP should be considered in situations that require Trendelenburg positioning, such as exercise or surgery.
Head-Down Tilt ; Humans ; Intraocular Pressure* ; Iron-Dextran Complex ; Male ; Supine Position ; Volunteers

BACKGROUND: The respiratory cycle alters the size of the right internal jugular vein (RIJV). We assessed the changes in RIJV size during the respiratory cycle in patients under positive pressure ventilation. Moreover, we examined the effects of positive-end expiratory pressure (PEEP) and the Trendelenburg position on respiratory fluctuations. METHODS: A prospective study of 24 patients undergoing general endotracheal anesthesia was performed. Images of the RIJV were obtained in the supine position with no PEEP (baseline, S0) and after applying three different maneuvers in random order: (1) a PEEP of 10 cmH2O (S10), (2) a 10degrees Trendelenburg tilt position (T0), and (3) a 10degrees Trendelenburg tilt position combined with a PEEP of 10 cmH2O (T10). Using the images when the area was smallest and largest, cross-sectional area (CSA), anteroposterior diameter, and transverse diameter were measured. RESULTS: All maneuvers minimized the fluctuation in RIJV size (all P = 0.0004). During the respiratory cycle, the smallest CSA compared to the largest CSA at S0, S10, T0, and T10 decreased by 28.3 8.5, 8.0, and 4.4%, respectively. Furthermore, compared to S0, a 10degrees Trendelenburg tilt position with a PEEP of 10 cmH2O significantly increased the CSA in the largest areas by 83.8% and in the smallest areas by 169.4%. CONCLUSIONS: A 10degrees Trendelenburg tilt position combined with a PEEP of 10 cmH2O not only increases the size of the RIJV but also reduces fluctuation by the respiratory cycle.
Anesthesia ; Head-Down Tilt* ; Humans ; Jugular Veins* ; Positive-Pressure Respiration ; Prospective Studies ; Supine Position