Effects of Posture and Prolonged Pneumoperitoneum on Hemodynamic Parameters during Laparoscopy

The Effect of Pneumoperitoneum on the Ankle-brachial Index of the Patients Undergoing Laparoscopic Cholecystectomy: An Observational Study

Background

Improvement in the perioperative care has led to increased use of minimally invasive surgeries. Multiple physiological changes during minimally invasive surgeries are attributed to the creation of pneumoperitoneum.

Materials and Methods

One hundred and nine patients who underwent laparoscopic cholecystectomy at a tertiary care hospital in north India meeting the inclusion and exclusion criteria were enrolled.

Results

Out of the total 109 patients, 13 were males and 96 females (M:F = 1:7.3), the mean basal metabolic rate was 28.95 kg/m2. The mean systolic and diastolic blood pressure of the upper limb were 134.33 + 17.545 and 80.69 + 11.59 respectively. The mean systolic and diastolic blood pressure in lower limb (LL) were 142.32 + 21.552 and 79.44 + 11.94, respectively. Significant rise in the SBP was noticed in LL at the time of creation of Pneumoperitoneum and after changing the position for surgery (P < 0.05). The diastolic pressure in the LL rises significantly in the LL after creation of pneumoperitoneum, at induction, after reverse Trendelenburg position and extubation (P < 0.05). The mean arterial pressure increased significantly in the LL after the creation of pneumoperitoneum and persisted till the extubation (P < 0.05). A significant rise of ankle-brachial index (ABI) was observed in the patients after the creation of pneumoperitoneum and it remained significant till 15 min into surgery (P < 0.05). There was no correlation of ABI with weight and age of the patients on Pearson correlation.

Conclusion

There is rise in ABI of the patients undergoing laparoscopic cholecystectomy at the time of creation of pneumoperitoneum, after Trendelenburg position and 15 min into surgery.

The intraoperative management of robotic-assisted laparoscopic prostatectomy

PURPOSE OF REVIEW

Robotic-assisted laparoscopic radical prostatectomy has become the second most commonly performed robotic surgical procedure worldwide, therefore, anesthesiologists should be aware of the intraoperative pathophysiological consequences. The aim of this narrative review is to report the most recent updates regarding the intraoperative management of anesthesia, ventilation, hemodynamics and central nervous system, during robotic-assisted laparoscopic radical prostatectomy.

RECENT FINDINGS

Surgical innovations and the advent of new technologies make it imperative to optimize the anesthesia management to provide the most holistic approach possible. In addition, an ageing population with an increasing burden of comorbidities requires multifocal attention to reduce the surgical stress.

SUMMARY

Total intravenous anesthesia (TIVA) and balanced general anesthesia are similar in terms of postoperative complications and hospital stay. Reversal of rocuronium is associated with shorter hospital stay and postanesthesia recovery time. Adequate PEEP levels improve oxygenation and driving pressure, and the use of a single recruitment maneuver after the intubation reduces postoperative pulmonary complications. Restrictive intravenous fluid administration minimizes bladder-urethra anastomosis complications and facial edema. TIVA maintains a better autoregulation compared with balanced general anesthesia. Anesthesiologists should be able to optimize the intraoperative management to improve outcomes.

The evaluation of cardiac functions in deep Trendelenburg position during robotic-assisted laparoscopic prostatectomy

Objective

This study aimed to demonstrate the reliability of the cardiac cycle efficiency value through its correlation with longitudinal strain by observing the effect of the deep Trendelenburg position.

Design

A prospective, observational study.

Setting

Single center.

Participants

Between May and September 2022, the hemodynamic parameters of 30 patients who underwent robotic assisted laparoscopic prostatectomy under general anesthesia were prospectively evaluated.

Measurements and main results

All invasive cardiac monitoring parameters and longitudinal strain achieved transesophageal echocardiography were recorded in pre-deep Trendelenburg position (T3) and 10th minute of deep Trendelenburg position (T4). Delta values were calculated for the cardiac cycle efficiency and longitudinal strain (values at T4 minus values at T3). The estimated power was calculated as 0.99 in accordance with the cardiac cycle efficiency values at T3 and T4 (effect size: 0.85 standard deviations of the mean difference: 0.22, alpha: 0.05). At T4, heart rate, pulse pressure variation, cardiac cycle efficiency, dP/dt and longitudinal strain were significantly lower than those at T3 (p = 0.009, p < 0.001, p < 0.001, and p < 0.001, respectively). There was a positive correlation between the delta-cardiac cycle efficiency and delta-longitudinal strain (R2 = 0.36, p < 0.001).

Conclusion

Although the absence of significant changes in mean arterial pressure and cardiac index after Trendelenburg position suggests that cardiac workload has not changed, changes in cardiac cycle efficiency and longitudinal strain indicate increased cardiac workload due to increased ventriculo-arterial coupling.

Review of robot-assisted laparoscopic surgery in management of infant congenital urology: Advances and limitations in utilization and learning

As robotic-assisted (RAL) surgery expanded to treat pediatric congenital disease, infant anatomy and physiology posed unique challenges that prompted adaptations to the technology and surgical technique, which are compiled and reviewed in this manuscript. From the beginning, collaboration with anesthesia is critical for a safe, efficient case including placement of an endotracheal tube rather than a laryngeal mask (LMA) and placement of a nasogastric tube and/or rectal tube to relieve distended stomach or bowel, respectively. Furthermore, end-tidal CO₂ (EtCO₂ ) is important for monitoring and predicting the effects of pneumoperitoneum on caridiovascular physiology, incranial pressure, and risk of acidosis and hypercarbia. Positioning can further exacerbate these effects and affect intra-abdominal working space. For infant robotic pyeloplasty and heminephrectomy, a "beanbag" is commonly used for stabilization in the lateral decubitus position. We advise against the use of a "baby bump" because it brings the bowels and vasculature more anterior than expected. Pnuemoperitoneum pressure of 8-10 mmHg during port placement maximizes safety, but thereafter, the pneumoperitoneum pressure can be minimized to 6-8 mmHg during the procedure without compromising the visual field. Port sites should be marked after insufflation, followed by the open Hasson technique for peritoneal access and port placement under direct vision with intussusception of the trocars to avoid vascular or bowel injury. Additional tips can be obtained through this manuscript, immersive fellowships, and mini-fellowships. Ulitmately, infant robotic surgery has the potential to benefit many children but is presently limited by the lack of pediatric-specific robotic technology and its associated costs.

Positive end-expiratory pressure setting based on transpulmonary pressure during robot-assisted laparoscopic prostatectomy: an observational intervention study

Background

In robot-assisted laparoscopic prostatectomy (RALP), concerns include the formation of atelectasis and reduced functional residual capacity. The present study aimed to examine the feasibility of positive end-expiratory pressure (PEEP) setting based on transpulmonary pressure (Ptp) as well as the effects of incremental PEEP on respiratory mechanics, blood gases, cerebral oxygenation (rSO₂), and hemodynamics.

Methods

Fourteen male patients who were scheduled to receive RALP were recruited. Patients received mechanical ventilation (tidal volume of 6 mL kg⁻¹) and were placed in Trendelenburg position with positive-pressure capnoperitoneum. PEEP levels were increased from 0 to 15 cmH₂O (5 cmH₂O per increase) every 30 min. PEEP levels were assessed where end-expiratory Ptp levels of ≥0 cmH₂O were achieved (PtpEEP0). Airway pressure, esophageal pressure, cardiac index, and blood gas and rSO₂ values were measured after 30 min at each PEEP step and respiratory mechanics were calculated.

Results

With increasing PEEP levels from 0 to 15 cmH₂O or PtpEEP0, the values of PaO₂ and respiratory system compliance increased, and the values of driving pressure decreased. The median PEEP level associated with PtpEEP0 was 15 cmH₂O. Respiratory system compliance values were higher at PtpEEP0 than those at PEEP5 (P = 0.02). Driving pressure was significantly lower at PtpEEP0 than at PEEP5 (P = 0.0036). The cardiac index remained unchanged, and the values of rSO₂ were higher at PtpEEP0 than at PEEP0 (right; P = 0.0019, left; P = 0.036).

Conclusions

PEEP setting determined by transpulmonary pressure can help achieve higher respiratory system compliance values and lower driving pressure without disturbing hemodynamic parameters.

Concomitant robot-assisted laparoscopic surgeries for upper and lower urinary tract malignancies: a comprehensive literature review

Worldwide, we have witnessed an expansion of robot-assisted laparoscopic surgery (RALS) and thanks to the global adoption of high-resolution diagnostic imaging technologies, an increased incidence of newly diagnosed prostatic, renal and bladder cancers has been recorded with concurrent second primary urological cancer diagnoses increasing by 1.5%. Diverse authors have reported their findings concerning synchronous multi-visceral malignances robotic treatment within the scientific literature. The aim of this study is to comprehensively review all reported articles describing concurrent upper and lower RALS using a singular robotic port scheme within the same intervention for renal malignances and concomitant prostatic or bladder cancers. To the best of our knowledge and vigorous literature search, this is the first study that comprehensively evaluates and reports all combined upper and lower urinary tract surgeries published so far. In carefully selected patients, thanks to multidisciplinary preoperative assessment and surgical planning a combined robotic approach can reduce the morbidity, complications, hospital admissions and the overall length of hospitalization.

Beneficial Effects of Intravenous Magnesium Administration During Robotic Radical Prostatectomy: A Randomized Controlled Trial

INTRODUCTION

Robotic radical prostatectomy requires prolonged pneumoperitoneum and a steep Trendelenburg position. Magnesium can attenuate the stress response and hemodynamic perturbations. This study aimed to evaluate the effects of intravenous magnesium administration on hemodynamics and the stress response in patients undergoing robotic radical prostatectomy.

METHODS

In this prospective, double-blind, randomized controlled study, 52 patients undergoing robotic radical prostatectomy were randomized into two groups: 26 in the magnesium group and 26 in the control group. The patients in the magnesium group received magnesium sulfate 50 mg/kg intravenously, followed by infusion at a rate of 10 mg/kg/h during surgery. The patients in the control group received an equal volume of 0.9% saline. The primary outcomes were the changes in heart rate and mean arterial pressure (MAP) during surgery. The serum stress hormones (adrenocorticotropic hormone, cortisol, epinephrine, and norepinephrine) were also measured.

RESULTS

MAP showed a significant intergroup difference over time (P_group*time = 0.017); it increased significantly at 5 min after Trendelenburg position in the control group and decreased significantly at 30 min after Trendelenburg position in the magnesium group. The intergroup difference in the change in cortisol concentrations was significant over time (P_group*time = 0.006). The cortisol concentration decreased significantly from baseline to 24 h after surgery in the magnesium group but did not change significantly in the control group. The requirement for intraoperative remifentanil was 35% lower in the magnesium group (P = 0.011), and the severity of postoperative pain at 30 min and 6 h after surgery was also lower in the magnesium group (P = 0.024 and P = 0.015).

CONCLUSION

There is a possibility that intravenous magnesium administration during robotic radical prostatectomy reduces the increases in arterial pressure, cortisol concentrations, opioid requirements, and postoperative pain.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02833038.

Combined Retroperitoneal and Transperitoneal Laparoscopic Procedures by a Single Surgeon: Boon to Economically and Medically Backward Areas

Introduction This study was done to evaluate our experience of combining a retroperitoneal laparoscopic urological operation with other transperitoneal laparoscopic operations. Materials and methods We present a retrospective study of a series of 20 cases of retroperitoneal laparoscopic urological surgeries combined with at least one transperitoneal laparoscopic procedures, performed by a senior minimally invasive surgeon, between March 2013 and August 2020. We have excluded three patients where either of the procedures required conversion to open surgery. We retrospectively reviewed all the data regarding the patient's demographics, combined surgical procedures done, operative time taken, blood loss, intraoperative and postoperative complications, and days of hospital stay. Results Total of 20 patients had undergone simultaneous retroperitoneal and transperitoneal laparoscopic procedures. A total of nine (45%) cases comprised a combination of retroperitoneal laparoscopic ureterolithotomy and laparoscopic cholecystectomy. Two patients had undergone a combination of three laparoscopic procedures in the same operation. The mean hospital stay was 3.6 days. Blood loss was minimal to moderate in all the patients, none needed any perioperative blood transfusion. No major complications were noted in any patients. Conclusion Combining a retroperitoneal laparoscopic urological procedure with another transperitoneal laparoscopic surgery is very much feasible. It becomes even easier and relevant provided both the procedures are performed by a single, experienced laparoscopic surgeon.

Combined Robotic Surgery for Double Renal Masses and Prostate Cancer: Myth or Reality?

With the widespread use of imaging modalities performed for the staging of prostate cancer, the incidental detection of synchronous tumors is increasing in frequency. Robotic surgery represents a technical evolution in the treatment of solid tumors of the urinary tract, and it can be a valid option in the case of multi-organ involvement. We reported a case of synchronous prostate cancer and bifocal renal carcinoma in a 66-year-old male. We performed the first case of a combined upper- and lower-tract robotic surgery for a double-left-partial nephrectomy associated with radical prostatectomy by the transperitoneal approach. A comprehensive literature review in this field has also been carried out. Total operative time was 265 min. Renal hypotension time was 25 min. Blood loss was 250 mL. The patient had an uneventful postoperative course. No recurrence occurred after 12 months. In the literature, 10 cases of robotic, radical, or partial nephrectomy and simultaneous radical prostatectomy have been described. Robotic surgery provides less invasiveness than open surgery with comparable oncological efficacy, overcoming the limitations of the traditional laparoscopy. During robotic combined surgery for synchronous tumors, the planning of the trocars' positioning is crucial to obtain good surgical results, reducing the abdominal trauma, the convalescence, and the length of hospitalization with a consequent cost reduction. Rare complications can be related to prolonged pneumoperitoneum. Simultaneous robotic prostatectomy and partial nephrectomy appears to be a safe and feasible surgical option in patients with synchronous prostate cancer and renal cell carcinoma.

The effects of laparoscopic urologic surgery on cardiac functions: A pulse wave velocity study

OBJECTIVE

The aim of this study is to evaluate the effects of laparoscopic urologic surgery on cardiac functions by the parameter pulse wave velocity (PWV), a noninvasive method.

MATERIAL AND METHODS

Between July 2012 and February 2013, a total of 47 patients were included in this prospective controlled study. Patients who have been scheduled for laparoscopic surgery (LS) (n=30) and open surgery (n=17) were enrolled in the study. Preoperative, perioperative, and postoperative cardiovascular parameters were measured by a PWV instrument, and the results were compared between laparoscopic (L) group and open (C) group.

RESULTS

In the L group, compared to preoperative values, perioperative systolic arterial pressure, diastolic arterial pressure, and mean arterial pressure increased considerably, by 2.6%, 7.9%, and 4.7%, respectively. This was in contrary to reductions in these parameters by 9.5%, 5.7%, and 10%, respectively, in the C group. For the L group, cardiac output (CO) and cardiac index (CI) were increased in the perioperative period and decreased in the postoperative period. For the C group, there were no changes in measurements of perioperative and postoperative CO and CI. However, these changes in CO and CI were not significantly different between the L and C groups. Postoperative large artery elasticity index decreased in both groups. However, these changes did not represent significant difference between groups.

CONCLUSION

Compared to open surgery, LS may cause increases in perioperative blood pressures. In addition, increased blood pressures may last even on the first postoperative day. These effects may be more important for patients with high cardiovascular risk.

Synchronous abdominal tumors: is combined laparoscopic surgery in a single approach a safe option?

Background and Purpose:

Recent advances in cancer treatment have resulted in bet- ter prognosis with impact on patient's survival, allowing an increase in incidence of a second primary neoplasm. The development of minimally invasive surgery has provided similar outcomes in comparison to open surgery with potentially less mor- bidity. Consequently, this technique has been used as a safe option to simultaneously treat synchronous abdominal malignancies during a single operating room visit. The objective of this study is to describe the experience of two tertiary cancer hospitals in Brazil, in the minimally invasive treatment of synchronous abdominal neoplasms and to evaluate its feasibility and peri-operative results.

Materials and Methods:

We retrospectively reviewed the data from patients who were submitted to combined laparoscopic procedures performed in two tertiary hospitals in Brazil from May 2009 to February 2015.

Results:

A total of 12 patients (9 males and 3 females) with a mean age of 58.83 years (range: 33 to 76 years) underwent combined laparoscopic surgeries for the treatment of at least one urological disease. The total average duration of surgery was 339.8 minutes (range: 210 to 480 min). The average amount of intraoperative bleeding was 276.6mL (range: 70 to 550mL) and length of hospitalization was 5.08 days (range: 3 to 10 days). Two patients suffered minor complications regarding Clavien system during the immediate postoperative period.

Conclusions:

Combined laparoscopic surgery for the treatment of synchronous tumors is feasible, viable and safe. In our study, there was a low risk of postoperative morbidity.

The impact of obesity on pulmonary deterioration in patients undergoing robotic-assisted laparoscopic prostatectomy

Obesity affects respiratory and hemodynamic function in anesthetized patients. The aim of this study was to evaluate the influence of the body mass index (BMI) on pulmonary changes in a permanent 45° steep Trendelenburg position (STP) during robotic-assisted laparoscopic prostatectomy (RALP). 51 patients undergoing RALP under standardized anesthesia were included. Perioperative pulmonary function and oxygenation were measured in awake patients (T₀), 20 min after the induction of anesthesia (T₁), after insufflation of the abdomen in supine position (T₂), after 30 min in STP (T₃), when controlling Santorini's plexus in STP (T₄), before awakening while supine (T₅), and after 45 min in the recovery room (T₆). Patient-specific and time-dependent factor on ventilation and predicted peak inspiratory pressure (PIP), driving pressure (P_driv) and lung compliance (LC) in a linear regression model were calculated. PIP and P_driv increased significantly after induction of capnoperitoneum (T_2-4) (p < 0.0001). In univariate mixed effects models, BMI was found to be a significant predictor for PIP and P_driv increase and LC decrease. Obese patients a BMI > 31 kg/m² reached critical PIP values ≥ 35 cmH₂O. Postoperative oxygenation represented by the PaO₂/FiO₂ ratio was significantly decreased compared to T₀ (p < 0.0001). Obesity in combination with STP and capnoperitoneum during RALP has a profound effect on pulmonary function. Increased PIP and P_driv and decreased LC are directly correlated with a high BMI. Changes in PIP, P_driv and LC during RALP may be predicted in relation to patient's BMI for consideration in the preoperative setting. Trial registration number Z-2014-0387-6. Registered on 8 July 2014.

Pediatric anesthesia for minimally invasive surgery in pediatric urology

Laparoscopic or robotic minimally invasive approaches have become the standard of care for many urological pediatric surgical procedures. Anesthetic concerns for conventional and robotic laparoscopy are similar since they both require insufflations of CO₂ to allow visualization of surgical field and perform surgery. Even if required insufflation pressures and volumes are lower in pediatric patients (given the small size of the abdomen and laxity of the abdominal walls), the associated increase of intra-abdominal pressure, along with absorption of CO₂ and surgical positioning requirement, may result in neurendocrine and mechanical impact capable to mine cardiopulmonary function. Moreover, laparoscopic approach may require specific positioning. A correct positioning is essential to allow the surgical team to optimally and safely access to the patient. The knowledge of patient's health status, along with the multiple physiologic changes that can occur and specific potential complications, allow the anesthesiologist to provide a safer an aesthesia.

Obesity is associated with decreased lung compliance and hypercapnia during robotic assisted surgery

Robotic assisted surgery (RAS) represents a great challenge for anesthesiology due to the increased intraabdomial pressures required for surgical optimal approach. The changes in lung physiology are difficult to predict and require fast decision making in order to prevent altered gas exchange. The aim of this study was to document the combined effect of patient physical status, medical history and intraoperative position during RAS on lung physiology and to determine perioperative risk factors for hypercapnia. We prospectively analyzed 62 patients who underwent elective RAS. Age, co-morbidities and body mass index (BMI) were recorded before surgery. Ventilatory parameters and arterial blood gas analysis were determined before induction of anesthesia, after tracheal intubation and on an hourly basis until the end of surgery. In RAS, the induction of pneumoperitoneum was associated with a significant decrease in lung compliance from a mean of 42.5–26.7 ml cm H₂O⁻¹ (p = 0.001) and an increase in plateau pressure from a mean of 16.1 mmHg to a mean of 23.6 mmHg (p = 0.001). Obesity, demonstrated by a BMI over 30, significantly correlates with a decrease in lung compliance after induction of anesthesia (p = 0.001). A significant higher increase in arterial CO₂ tension was registered in patients undergoing RAS in steep Trendelenburg position (p = 0.05), but no significant changes in end-tidal CO₂ were recorded. A higher arterial to end-tidal CO₂ tension gradient was observed in patients with a BMI > 30 (p < 0.001). In conclusion, patients’ physical status, especially obesity, represents the main risk factor for decreased lung compliance during RAS and patient positioning in either Trendelenburg or steep Trendelenburg during surgery has limited effects on respiratory physiology.

Dynamic Arterial Elastance in Predicting Arterial Pressure Increase After Fluid Challenge During Robot-Assisted Laparoscopic Prostatectomy: A Prospective Observational Study

During robot-assisted laparoscopic prostatectomy, specific physiological conditions such as carbon dioxide insufflation and the steep Trendelenburg position can alter the cardiac workload and cerebral hemodynamics. Inadequate arterial blood pressure is associated with hypoperfusion, organ damage, and poor outcomes. Dynamic arterial elastance (Ea) has been proposed to be a useful index of fluid management in hypotensive patients. We therefore evaluated whether dynamic Ea can predict a mean arterial pressure (MAP) increase ≥ 15% after fluid challenge during pneumoperitoneum and the steep Trendelenburg position.We enrolled 39 patients receiving robot-assisted laparoscopic prostatectomy. Fluid challenge was performed with 500 mL colloids in the presence of preload-dependent conditions and arterial hypotension. Patients were classified as arterial pressure responders or arterial pressure nonresponders according to whether they showed an MAP increase ≥15% after fluid challenge. Dynamic Ea was defined as the ratio between the pulse pressure variation and stroke volume variation. Receiver operating characteristic curve analysis was performed to assess the arterial pressure responsiveness after fluid challenge during robot-assisted laparoscopic prostatectomy.Of the 39 patients, 17 were arterial pressure responders and 22 were arterial pressure nonresponders. The mean dynamic Ea before fluid challenge was significantly higher in arterial pressure responders than in arterial pressure nonresponders (0.79 vs 0.61, P < 0.001). In receiver operating characteristic curve analysis, dynamic Ea showed an area under the curve of 0.810. The optimal cut-off value of dynamic Ea for predicting an MAP increase of ≥ 15% after fluid challenge was 0.74.Dynamic Ea can predict an MAP increase ≥ 15% after fluid challenge during robot-assisted laparoscopic prostatectomy. This result suggests that evaluation of arterial pressure responsiveness using dynamic Ea helps to maintain an adequate arterial blood pressure and to improve perioperative outcomes in preload-dependent patients receiving robot-assisted laparoscopic prostatectomy under pneumoperitoneum and in the steep Trendelenburg position.

Cardiac and Liver Marker Alterations After Laparoscopic Gynaecologic Operations

OBJECTIVE

In our study, we aimed to investigate the effect of laparoscopic procedures in which the abdominal cavity at a Trendelenburg position of 15 degrees was insufflated with CO2 on cardiac and liver markers.

METHODS

Forty patients scheduled for laparoscopic gynaecological surgery were included in the study. Venous blood samples were taken the day before operation and 6 hours after surgery, and later, lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase-MB (CK-MB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), myoglobin (MY) and d-dimer (d-D) were measured.

RESULTS

There was no statistically significant difference in the values of preoperative and postoperative ALT (16.8±9.4 and 17.8±9.3; p=0.579), AST (19.4±7 and 20.9±7.6; p=0.361) and ALP (65.2±16.2 and 63.3±16.9; p=0.609), but LDH (385.1±117.3 and 460.6±156.3; p=0.003), CK (113.8±138.5 and 247.9±283.5; p=0.0001), CK-MB (22.8±13.3 and 28.7±16; p=0.011), MY (28.1±12.9 and 138.8±129; p=0.0001) and d-D (509.5±815: 1026±1054; p=0.0001) increased significantly.

CONCLUSION

After laparoscopic operations in the Trendelenburg position, postoperative serum ALT, AST and ALP levels, remained unchanged, when compared to preoperative values, but LDH, CK, CK-MB, myoglobin and d-dimer values increased significantly.

Cardiac and hemodynamic consequences during capnoperitoneum and steep Trendelenburg positioning: lessons learned from robot-assisted laparoscopic prostatectomy

STUDY OBJECTIVE

To determine and interpret the changes in preload, afterload, and cardiac function in the different phases of robot-assisted laparoscopic prostatectomy.

DESIGN

Prospective, observational monocenter study.

SETTING

Operating room at a university hospital.

PATIENTS

31 consecutive, ASA physical status 1, 2, and 3 patients.

INTERVENTIONS

Observations were made at 5 distinct time points: baseline after induction of anesthesia, after initiation of capnoperitoneum, immediately after a 45° head-down tilt, 15 minutes after the 45° head-down tilt was established, after the release of the capnoperitoneum, and 5 minutes after the patient was returned to a horizontal position (end).

MEASUREMENTS

Transpulmonary thermodilution and pulse contour analysis were used to record hemodynamic changes in preload, afterload, and cardiac function.

MAIN RESULTS

While central venous pressure increased threefold from baseline, none of the other preload parameters showed excessive fluid overload or demand. There was no significant change in cardiac contractility over time. Afterload increased significantly during the capnoperitoneum and significantly decreased compared with baseline after the release of abdominal pressure at the end of the procedure. Heart rate and cardiac index increased significantly during robot-assisted laparoscopic prostatectomy.

CONCLUSIONS

Selective arterial vasodilation at the time of capnoperitoneum may normalize afterload and myocardial oxygen demand.

Simultaneous robot-assisted laparoendoscopic single-site partial nephrectomy and standard radical prostatectomy

Recently, patients with urologic malignancies are treated with robot-assisted surgery and the expanded role of robot-assisted surgery includes even those patients with two concomitant primary urologic malignancies. In an effort to further reduce port site-related morbidity, robot-assisted laparoendoscopic single-site surgery (RLESS) has been developed. Therefore, we present herein our early experience and feasibility of simultaneous RLESS partial nephrectomy and standard robotrobot- assisted laparoendoscopic radical prostatectomy (RALP) on 3 patients with synchronous renal masses and prostate cancer.

Anesthetic considerations for robotic cystectomy: a prospective study

BACKGROUND AND OBJECTIVES

Robotic cystectomy is rapidly becoming a part of the standard surgical repertoire for the treatment of prostate cancer. Our aim was to describe respiratory and hemodynamic challenges and the complications observed in robotic cystectomy patients.

PATIENTS

Sixteen patients who underwent robotic surgery between December 2009 and January 2011 were prospectively enrolled. Main outcome measures were non-invasive monitoring, invasive monitoring and blood gas analysis performed at supine (T0), Trendelenburg (T1), Trendelenburg+pneumoperitoneum (T2), Trendelenburg-before desufflation (T3), Trendelenburg (after desufflation) (T4), and supine (T5) positions.

RESULTS

There were significant differences between T0-T1 and T0-T2 with lower heart rates. The mean arterial pressure value at T1 was significantly lower than T0. The central venous pressure value was significantly higher at T1, T2, T3, and T4 than at T0. There was no significant difference in the PET-CO2 value at any time point compared with T0. There were no significant differences in respiratory rate at any time point compared with T0. The mean f values at T3, T4, and T5 were significantly higher than T0. The mean minute ventilation at T4 and T5 were significantly higher than at T0. The mean plateau pressures and peak pressures at T1, T2, T3, T4, and T5 were significantly higher than the mean value at T0.

CONCLUSIONS

Although the majority of patients generally tolerate robotic cystectomy well and appreciate the benefits, anesthesiologists must consider the changes in the cardiopulmonary system that occur when patients are placed in Trendelenburg position, and when pneumoperitoneum is created.

Anaesthesia for laparoscopic kidney transplantation: Influence of Trendelenburg position and CO2 pneumoperitoneum on cardiovascular, respiratory and renal function

Background:

Laparoscopic donor nephrectomy is a routine practice since 1995. Until now, the recipient has always undergone open surgery for transplantation. In our institute, laparoscopic kidney transplantation (LKT) started in 2010. To facilitate this surgery, the patient must be in steep Trendelenburg position for a long duration. Hence, we decided to study the effect of CO2 pnuemoperitoneum and Trendelenburg position in chronic renal failure (CRF) patients undergoing LKT.

Methods:

A total of 20 adult CRF patients having mean age of 31.7±10.36 years and body mass index 19.65±3.41 kg/m² without significant coronary artery disease were selected for the procedure. Cardiovascular parameters heart rate (HR), mean arterial pressure (MAP), Central venous pressure (CVP) and respiratory parameters (ETCO₂, peak airway pressure) were noted at the time of induction, after induction, 15 min after creation of pnuemoperitoneum, 30 min after Trendelenburg position, 15 min after decompression of pnuemoperitonuem and after extubation. Arterial blood gas analysis was carried out after induction, 15 min after creation of pnuemoperitoneum, 30 min after Trendelenburg position and 15 min after clamp release. Total duration of surgery, anastomosis time, time for the establishment of urine output and total urine output were noted. Serum creatinine on the 1^st and 7^th post-operative day were recorded.

Results:

Significant increase in HR was observed after creation of CO₂ pneumoperitoneum and just before extubation. Significant increase in the MAP and CVP was noted after creation of pneumoperitoneum and after giving Trendelenburg position. No significant rise in the ETCO₂ and PaCO₂ was observed. Significant increase in the base deficit was observed after the clamp release, but none of the patients required correction.

Conclusion:

LKT performed in steep Trendelenburg position with CO₂ pneumoperitoneum significantly influenced cardiovascular and respiratory homeostasis; however, measured parameters remained within clinically acceptable range without affecting early function of the transplanted kidney.

Cardiovascular and respiratory effects of the degree of head-down angle during robot-assisted laparoscopic radical prostatectomy

BACKGROUND

Robot-assisted laparoscopic radical prostatectomy (RALP) requires a steep Trendelenburg position and CO2 pneumoperitoneum for several hours to secure the surgical visual field. The present study was performed to investigate the influence of each angle of Trendelenburg position during RALP on cardiovascular and respiratory homeostasis.

METHODS

Forty-seven ASA physical status 1 and 2 patients underwent open retropubic radical prostatectomy (RRP) or RALP. Patients receiving RALP were randomized to undergo the operation in the 20°, 25° or 30° Trendelenburg position. Heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR), end-tidal CO2 pressure (PetCO2 ), tidal volume (Vt), peak inspiratory pressure (PIP) and dynamic compliance (Cdyn) were recorded during the operation.

RESULTS

Angle of head-down tilt was significantly correlated with MAP, PIP and Cdyn, but not with HR, RR or PetCO2 . MAP decreased gradually over time in each group in the Trendelenburg position with pneumoperitoneum. As the angle of head-down tilt became stronger, MAP, RR, PetCO2 and PIP tended to increase and Cdyn tended to decrease.

CONCLUSIONS

This study demonstrated that the degree of the head-down angle at RALP affected the cardiovascular and respiratory parameters. Pneumoperitoneum with head-down position in RALP influenced the cardiovascular and respiratory system to a greater extent than RRP, and these effects were stronger with deeper head-down angle.

Arterial to end-tidal carbon dioxide pressure gradient increases with age in the steep Trendelenburg position with pneumoperitoneum

Background

Several factors affect the end-tidal carbon dioxide pressure (P_ETCO₂) and increase the arterial to end-tidal carbon dioxide pressure gradient (P_a-ETCO₂) during general anesthesia. We evaluated the relationship between age and P_a-ETCO₂ during pneumoperitoneum in the steep Trendelenburg position in patients undergoing robot-assisted laparoscopic prostatectomy (RALP).

Methods

Ninety-two consecutive patients undergoing RALP were divided by age into a middle-aged (45-65 years) and an elderly (> 65 years) group. Anesthesia was standardized. Heart rate, mean arterial pressure, peak inspiratory pressure, lung compliance, minute ventilation, P_aO₂, P_ETCO₂, P_aCO₂, and P_a-ETCO₂ were measured 10 min after intubation in the supine position without pneumoperitoneum (T0); and 10 (T1), 60 (T2), and 120 (T3) min after pneumoperitoneum in the Trendelenburg position.

Results

Although P_ETCO₂ did not change significantly during surgery, PaCO₂ and P_a-ETCO₂ increased gradually with time during pneumoperitoneum in the Trendelenburg position, and both parameters showed greater increases in the elderly than in the middle-aged group. Simple linear regression analyses revealed significant correlations between age and P_a-ETCO₂ at T0 (P = 0.018), T1 (P = 0.006), T2 (P < 0.001), and T3 (P = 0.001). Linear mixed model analysis showed that P_a-ETCO₂ was associated statistically significantly with age and duration of pneumoperitoneum in the Trendelenburg position, but age and duration of pneumoperitoneum in the Trendelenburg position were not associated (P = 0.090).

Conclusions

The magnitude of P_a-ETCO₂ during pneumoperitoneum in the steep Trendelenburg position increased with age, which could be attributed to age-related respiratory physiological changes.

Hemodynamic changes during robotic radical prostatectomy

BACKGROUND

Effect on hemodynamic changes and experience of robot-assisted laparoscopic radical prostatectomy (RALRP) in steep Trendelenburg position (45°) with high-pressure CO(2) pneumoperitoneum is very limited. Therefore, we planned this prospective clinical trial to study the effect of steep Tredelenburg position with high-pressure CO(2) pneumoperitoneum on hemodynamic parameters in a patient undergoing RALRP using FloTrac/Vigileo™1.10.

METHODS

After ethical approval and informed consent, 15 patients scheduled for RALRP were included in the study. In the operation room, after attaching standard monitors, the radial artery was cannulated. Anesthesia was induced with fentanyl (2 μg/kg) and thiopentone (4-7 mg/kg), and tracheal intubation was facilitated by vecuronium bromide (0.1 mg/kg). The patient's right internal jugular vein was cannulated and the Pre Sep™ central venous oximetry catheter was connected to it. Anesthesia was maintained with isoflurane in oxygen and nitrous oxide and intermittent boluses of vecuronium. Intermittent positive-pressure ventilation was provided to maintain normocapnea. After CO(2) pneumoperitoneum, position of the patient was gradually changed to 45° Trendelenburg over 5 min. The robot was then docked and the robot-assisted surgery started. Intraoperative monitoring included central venous pressure (CVP), stroke volume (SV), stroke volume variation (SVV), cardiac output (CO), cardiac index (CI) and central venous oxygen saturation (ScvO(2)).

RESULTS

After induction of anesthesia, heart rate (HR), SV, CO and CI were decreased significantly from the baseline value (P>0.05). SV, CO and CI further decreased significantly after creating pneumoperitoneum (P>0.05). At the 45° Trendelenburg position, HR, SV, CO and CI were significantly decreased compared with baseline. Thereafter, CO and CI were persistently low throughout the 45° Trendelenburg position (P=0.001). HR at 20 min and 1 h, SV and mean arterial blood pressure after 2 h decreased significantly from the baseline value (P>0.05) during the 45° Trendelenburg position. CVP increased significantly after creating pneumoperitoneum and at the 45° Trendelenburg position (after 5 and 20 min) compared with the baseline postinduction value (P>0.05). All these parameters returned to baseline after deflation of CO(2) pneumoperitoneum in the supine position. There were no significant changes in SVV and ScvO(2) throughout the study period.

CONCLUSIONS

The steep Trendelenburg position and CO(2) pneumoperitoneum, during RALRP, leads to significant decrease in stroke volume and cardiac output.

Intra-operative oxygen delivery in infusion volume-optimized patients undergoing laparoscopic colorectal surgery within an enhanced recovery programme: the effect of different analgesic modalities

AIM

Patients undergoing major open surgery who have an indexed oxygen delivery (DO(2) I) > 600 ml/min/m(2) have been shown to have a lower incidence of morbidity and mortality compared with those whose DO(2) I is below this level. Laparoscopy and Trendelenburg positioning cause a reduction in DO(2) I. We aimed to quantify the effect of the type of analgesia on DO(2) I and to correlate the DO(2) I achieved with the incidence of anastomotic leakage in patients undergoing laparoscopic surgery.

METHOD

Following ethical approval, patients were randomized to receive spinal anaesthesia (Group S), epidural analgesia (Group E) or intravenous morphine (Group P) followed by postoperative patient-controlled analgesia (PCA). In addition to standard monitoring, oesophageal Doppler monitoring of the stroke volume allowed directed intravenous fluid therapy. The mean DO(2) I was compared with the anastomotic leakage rate.

RESULTS

Seventy-five patients were recruited (Group S, 27; Group E, 23; Group P, 25). The mean (range) DO(2) I for all patients was 490 (230-750) ml/min/m(2) . The analgesic modality had no effect on DO(2) I. Of the 18 patients with a DO(2) I of < 400 ml/min/m(2) , four (22%) developed anastomotic leakage compared with one (%) of the 57 patients with a DO(2) I of > 400 ml/min/m(2) (P = 0.01).

CONCLUSION

The analgesic modality used had no effect on the DO(2) I achieved. Anastomotic leakage was significantly higher in patients with a DO(2) I of < 400 ml/min/m(2) . A further study assessing the outcome after raising the DO(2) I with inotropes is required.

[Intraoperative surgical and anesthesiological problems and the consequences for surgery]

Although the procedures for severe intraoperative complications have largely been defined, in everyday life less dramatic but equally important problems and issues arise which are controversially debated between treating surgeons and the anesthesiologists. Preoperative anemia, transfusion therapy, fluid management, patient positioning, hypothermia and neuromuscular blockade are the focus of the occasionally conflicting interests of anesthesiologists and surgeons. Good reciprocal communication and mutual understanding are a requirement for proactive management of complications. The overall objective is the reduction of intraoperative risks thereby reducing morbidity and mortality. This can be achieved through modern fluid management, blood conserving techniques and maintenance of normothermia. Surgeons further require an optimal view during minimally invasive surgery even by complex patient positioning and adequate neuromuscular blockade.

Initial clinical experience of simultaneous robot-assisted bilateral partial nephrectomy and radical prostatectomy

A 62-year-old male patient with prostate cancer and bilateral renal cell carcinoma underwent a simultaneous robot-assisted bilateral partial nephrectomy and radical prostatectomy. We describe our initial experience of combined operation with a port strategy allowing reuse of ports and surgical considerations because of prolonged pneumoperitoneum.

Bilateral ischaemic optic neuropathy following laparoscopic proctocolectomy: a case report

INTRODUCTION

Perioperative visual loss occurring during non-ocular surgery is a devastating event. Ischaemic optic neuropathy (ION) is a complication described following many procedures. We report the first case of ION occurring during laparoscopic proctocolectomy and discuss the aetiological factors.

CASE HISTORY

A 58-year-old male presented with rectal bleeding and was diagnosed with an adenocarcinoma of the sigmoid colon. A very difficult laparoscopic sigmoidectomy and a low anterior resection of the rectum with an end colostomy were carried out. The technical difficulties were due to body habitus and the size and position of the tumour. The operation lasted over six hours. On the first day postoperatively, the patient complained of blurred vision. Examination showed that he had suffered bilateral ION.

DISCUSSION

Despite the growing numbers of laparoscopic operations, ION has rarely been described. The cases that were published involved laparoscopic prostatectomy and a prolonged steep Trendelenburg position. We postulate that the patient presented here had suffered both from a relative hypotension and from an acute rise in the intraorbital pressure due to patient position, both factors combining to cause a disruption to ocular perfusion resulting in ION with severe permanent visual damage.

Overcoming the challenges of robot-assisted radical prostatectomy

Robot-assisted radical prostatectomy (RARP) is the most commonly performed robotic procedure worldwide and is firmly established as a standard treatment option for localised prostate cancer. Part of the explanation for the rapid uptake of RARP is the reported gentler learning curve compared with the challenges of laparoscopic radical prostatectomy (LRP). However, robotic surgery is still fraught with potential difficulties and avoiding complications while on the steepest part of the learning curve is critical. Furthermore, as surgeons progress there is a tendency to take on increasingly complex cases, including patients with difficult anatomy and prior surgery, and these cases present a unique challenge. Significant intra-abdominal adhesions may be identified following open surgery, or dense periprostatic inflammation may be encountered following TURP; large prostate gland size and median lobes may alter bladder neck anatomy, making difficult subsequent urethro-vesical anastomosis. Even experienced robotic surgeons will be challenged by salvage RARP. Approaching these problems in a structured manner allows many of the problems to be overcome. We discuss some of the specific techniques to deal with these potential difficulties and highlight ways to avoid making serious mistakes.

Peripheral venous pressure as an alternative to central venous pressure in patients undergoing laparoscopic colorectal surgery

BACKGROUND

Peripheral venous pressure (PVP) is strongly correlated with central venous pressure (CVP) during various surgeries. Laparoscopic surgery in the Trendelenburg position with pneumoperitoneum typically increases CVP. To determine whether PVP convincingly reflects changes in CVP, we evaluated the correlation between PVP and CVP in patients undergoing laparoscopic colorectal surgery.

METHODS

Both CVP and PVP were measured simultaneously at predetermined time intervals during elective laparoscopic colorectal surgery in 42 patients without cardiac disease. The pairs of venous pressure measurements were analysed for correlation, and the Bland-Altman plots of repeated measures were used to evaluate the agreement between CVP and PVP.

RESULTS

A total of 420 data pairs were obtained. The overall mean CVP was 11.3 (sd 4.5) mm Hg, which was significantly lower than the measured PVP of mean 12.1 (4.5) mm Hg (P=0.005). There was a strong positive correlation between overall CVP and PVP (correlation coefficient=0.96, P<0.0001). The mean bias (PVP-CVP) corrected for repeated measurements using random-effects modelling was 0.9 mm Hg [95% confidence interval (CI) 0.54-1.19 mm Hg] with 95% limits of agreement of -1.2 mm Hg (95% CI -1.75 to -0.62 mm Hg) to 2.9 mm Hg (95% CI 2.35-3.48 mm Hg).

CONCLUSIONS

PVP displays a strong correlation and agreement with CVP under the increased intrathoracic pressure of pneumoperitoneum in the Trendelenburg position and may be used as an alternative to CVP in patients without cardiac disease undergoing laparoscopic colorectal surgery.

Hemodynamic perturbations during robot-assisted laparoscopic radical prostatectomy in 45° Trendelenburg position

BACKGROUND

Robot-assisted laparoscopic radical prostatectomy has gained widespread use. However, circulatory effects in patients subjected to an extreme Trendelenburg position (45°) are not well characterized.

METHODS

We studied 16 patients (ASA physical status I-II) with a mean age of 59 years scheduled for robot-assisted laparoscopic radical prostatectomy (45° head-down tilt, with an intraabdominal pressure of 11-12 mm Hg). Hemodynamics, echocardiography, gas exchange, and ventilation-perfusion distribution were investigated before and during pneumoperitoneum, in the Trendelenburg position and, in 8 of the patients, also after the conclusion of surgery.

RESULTS

In the 45° Trendelenburg position, central venous pressure increased almost 3-fold compared with the initial value, with an associated 2-fold increase in mean pulmonary artery pressure and pulmonary capillary wedge pressure (P<0.01). Mean arterial blood pressure increased by 35%. Heart rate, stroke volume, cardiac output, and mixed venous oxygen saturation were unaffected during surgery, as were echocardiographic heart dimensions. After induction of anesthesia, isovolumic relaxation time was prolonged, with no further change during the study. Deceleration time was normal and stable. In the horizontal position after pneumoperitoneum exsufflation, filling pressures and mean arterial blood pressure returned to baseline levels. Pneumoperitoneum reduced lung compliance by 40% (P<0.01). Addition of the Trendelenburg position caused a further decrease (P<0.05). Arterial blood acid-base balance was normal. End-tidal carbon dioxide tension increased whereas arterial carbon dioxide was unaffected with unchanged ventilation settings. Pneumoperitoneum increased PaO2 (P<0.05). Ventilation-perfusion distribution, shunt, and dead space were unaltered during the study.

CONCLUSIONS

Pneumoperitoneum and 45° Trendelenburg position caused 2- to 3-fold increases in filling pressures, without effects on cardiac performance. Filling pressures were normalized immediately after surgery. Lung compliance was halved. Gas exchange was unaffected. No perioperative cardiovascular complications occurred.

[The effects of pneumoperitoneum on heart rate, mean arterial blood pressure and cardiac output of hypertensive patients during laparoscopic colectomy]

PURPOSE

This study was performed to identify effects of pneumoperitoneum on hemodynamic changes of hypertensive patients undergoing laparoscopic colectomy under general anesthesia.

METHODS

Data collection was done from January 2 to June 10, 2008. Seventy-six patients, including 38 hypertensive patients, who had taken antihypertensive drugs more than 1 month and 38 normotensive patients undergoing laparoscopic colectomy were enrolled in this study. The hemodynamic parameters were heart rate (HR), mean arterial pressure (MAP) and cardiac output (CO) which were measured 7 times from before induction of anesthesia to 5 min after deflation of the pneumoperitoneum. Collected data were analyzed using Repeated Measures ANOVA and Bonferroni comparison method.

RESULTS

HR in the hypertensive group was significantly decreased at deflation of the pneumoperitoneum and 5 min after deflation of the pneumoperitoneum (p=.012). MAP in the hypertensive group was not different from the normotensive group (p=.756). CO in hypertensive group was significantly lower than normotensive group (p<.001) from immediately after pneumoperitoneum to 5 min after deflation of the pneumoperitoneum.

CONCLUSION

The results indicate that pneumoperitoneum during laparoscopic surgery does not lead to clinically negative hemodynamic changes in heart rate, mean arterial pressure or cardiac output of hypertensive patients, who have taken antihypertensive drugs for more than 1 month.

Impact of the patient's body position on the intraabdominal workspace during laparoscopic surgery

Background

The effects of the patient’s body position on the intraabdominal workspace in laparoscopic surgery were analyzed.

Methods

The inflated volume of carbon dioxide was measured after insufflation to a preset pressure of 15 mmHg for 20 patients with a body mass index (BMI) greater than 35 kg/m². The patients were anesthetized with full muscle relaxation. The five positions were (1) table horizontal with the legs flat (supine position), (2) table in 20° reverse Trendelenburg with the legs flat, (3) table in 20° reverse Trendelenburg with the legs flexed 45° upward at the hips (beach chair position), (4) table horizontal with the legs flexed 45° upward at the hips, and (5) table in 20° Trendelenburg with the legs flat. The positions were performed in a random order, and the first position was repeated after the last measurement. Repeated measure analysis of variance was used to compare inflated volumes among the five positions.

Results

A significant difference in inflated volume was found between the five body positions (P = 0.042). Compared with the mean inflated volume for the supine position (3.22 ± 0.78 l), the mean inflated volume increased by 900 ml for the Trendelenburg position or when the legs were flexed at the hips, and decreased by 230 ml for the reverse Trendelenburg position.

Conclusions

The Trendelenburg position for lower abdominal surgery and reverse Trendelenburg with flexing of the legs at the hips for upper abdominal surgery effectively improved the workspace in obese patients, even with full muscle relaxation.

The changes of central venous pressure by body posture and positive end-expiratory pressure

BACKGROUND

Central venous pressure (CVP) monitoring provides a useful estimate of the volume status of the systemic circulation. Both increase in the intrathoracic pressure by applying positive-end expiratory pressure (PEEP) and various patient positioning may commonly mislead the interpretation of CVP. We investigated the effect of body posture and different PEEPs on CVP in anesthetized patients.

METHODS

Ninety-one patients (ASA I or II) scheduled for elective surgery with supine (50 patients), lateral decubitus (27 patients), or prone position (14 patients) were included. After induction of general anesthesia, CVP, mean arterial pressure (MAP), heart rate (HR), end-tidal CO2 (EtCO2) and peak inspiratory pressure (PIP) were measured under different PEEP conditions of 0, 5, 10, and 15 cmH2O in each body posture.

RESULTS

CVP and PIP increased gradually by the increment of PEEP in patients with all positions. The magnitude of changes of CVP and PIP was significantly greater than other PEEP conditions when PEEP was 15 cmH2O, especially in prone position (P < 0.05). There were no differences in MAP, HR and EtCO2 during the increase of PEEP in all positions.

CONCLUSIONS

These results suggest that PEEP as much as 15 cmH2O may alter reliability of CVP in estimating adequate circulatory volumes, especially in prone position.

The effects of steep trendelenburg positioning on intraocular pressure during robotic radical prostatectomy

BACKGROUND

Intraocular pressure (IOP) increases in steep Trendelenburg positioning, but the magnitude of the increase has not been quantified. In addition, the factors contributing to this increase have not been studied in robot-assisted prostatectomy cases. In this study, we sought to quantify the changes in IOP and examine perioperative factors responsible for these changes while patients are in the steep Trendelenburg position during robotic prostatectomy.

METHODS

In this prospective study, we measured IOP using a Tono-pen XL in 33 patients undergoing robot-assisted prostatectomy. The IOP was measured before anesthesia while supine and awake (baseline T1), anesthetized and supine (T2), anesthetized after insufflation of the abdomen with carbon dioxide (CO(2)) (T3), anesthetized in steep Trendelenburg (T4), anesthetized in steep Trendelenburg at the end of the procedure (T5), anesthetized supine before awakening (T6), and 1 hr after awakening in the supine position (T7).

RESULTS

On average, IOP was 13.3 +/- 0.58 (mean +/- SE) mm Hg higher at the end of the period of steep Trendelenburg position (T5) compared with supine position T1 (P < 0.0001). The least square estimates for each time point in mm Hg were as follows: T1 = 15.7, T2 = 10.7, T3 = 14.6, T4 = 25.2, T5 = 29.0, T6 = 22.2, T7 = 17.0. Using univariate mixed effects models for the T1-T5 time periods, peak airway pressure, mean arterial blood pressure, ETco(2), and time were significant predictors of the IOP increase, whereas age, body mass index, blood loss, volume of IV fluid administered, mean airway pressure, and desflurane concentration were not predictive. In T4-T5, which involved no significant positional or perioperative interventions, we performed a multivariate analysis to evaluate predictors of IOP increases. Surgical duration (in minutes) and ETco(2) were the only significant variables predicting changes in IOP during stable and prolonged Trendelenburg positioning. On average, IOP increased 0.21 mm Hg per mm Hg increase in ETco(2) after adjusting for time. An increase of 0.05 mm Hg in IOP per minute of surgery on average was observed during this period in the Trendelenburg position after adjusting for ETco(2).

CONCLUSIONS

IOP reached peak levels at the end of steep Trendelenburg position (T5), on average 13 mm Hg higher than the preanesthesia induction (T1) value. Surgical duration and ETco(2) were the only significant predictors of IOP increase in the Trendelenburg position (T4-T5).

Development of a compact laparoscope manipulator (P-arm)

BACKGROUND

Laparoscope manipulating robots are useful for maintaining a stable view during a laparoscopic operation and as a substitute for the surgeon who controls the laparoscope. However, there are several problems to be solved. A large apparatus sometimes interferes with the surgeon. The setting and repositioning is awkward. Furthermore, the initial and maintenance costs are expensive. This study was designed to develop a new laparoscope manipulating robot to overcome those problems.

METHODS

We developed a compact robot applicable for various types of laparoscopic surgery with less expensive materials. The robot was evaluated by performing an in vitro laparoscopic cholecystectomy using extracted swine organs. Then, the availability of the robot to various operations was validated by performing a laparoscopic cholecystectomy, anterior resection of the rectum, and distal gastrectomy using a living swine. The reliability of the system was tested by long-time continuous running.

RESULTS

A compact and lightweight laparoscope manipulating robot by the name of P-arm was developed. The surgical time of an in vitro laparoscopic cholecystectomy with and without the P-arm was not different. The three types of operations were accomplished successfully. During the entire procedure, the P-arm worked without trouble and did not interfere with the surgeons. Continuous 8-h operating tests were performed three times and neither discontinuance nor trouble occurred with the system.

CONCLUSIONS

The P-arm worked steadily for various swine operations, without interfering with surgeon's work.

[Special features of laparoscopic operations from an anesthesiologic viewpoint: a review]

The value of laparoscopic procedures has increased over the last decade. Many patients undergoing laparoscopic surgery also have coexisting diseases. The hemodynamic effects of intraperitoneal carbon dioxide insufflation depend on the extent of intraperitoneal pressure, severity of preexisting cardiopulmonary diseases, volume state of the patient and alterations of acid-base balance due to a capnoperitoneum. In addition to endocrinologic reactions, patient positioning also affects hemodynamic parameters. In high risk patients extended cardiopulmonary monitoring with an arterial line and repeated blood gas analysis is recommended intraoperatively, in addition to assessment of end-expiratory CO(2). In this patient group the intra-abdominal pressure should be maintained in the range of 5-7 mmHg.