Central and peripheral adverse hemodynamic changes during laparoscopic surgery and their reversal with a novel intermittent sequential pneumatic compression device

The Effect of Intermittent Pneumatic Compression on Hemodynamics and Regional Cerebral Oxygen Saturation in Laparoscopic Bariatric Surgery with Mild Hypercapnia in the Steep Reverse Trendelenburg Position

Obesity negatively affects hemodynamics and cerebral physiology. We investigated the effect of the utilization of an intermittent pneumatic compression (IPC) device on hemodynamics and cerebral physiology in patients undergoing laparoscopic bariatric surgery under general anesthesia with lung-protective ventilation. Sixty-four patients (body mass index > 30 kg/m2) were randomly assigned to groups that received an IPC device (IPC group, n = 32) and did not (control group, n = 32). The mean arterial pressure (MAP), heart rate (HR), need for vasopressors, cerebral oxygen saturation (rSO2), and cerebral desaturation events were recorded. The incidence of intraoperative hypotension was not significantly different between groups (p = 0.153). Changes in MAP and HR over time were similar between groups (p = 0.196 and p = 0.705, respectively). The incidence of intraoperative cerebral desaturation was not significantly different between groups (p = 0.488). Changes in rSO2 over time were similar between the two groups (p = 0.190) during pneumoperitoneum. Applying IPC to patients with obesity in the steep reverse Trendelenburg position may not improve hemodynamic parameters, vasopressor requirements, or rSO2 values during pneumoperitoneum under lung-protective ventilation. During laparoscopic bariatric surgery, IPC alone has limitations in improving hemodynamics and cerebral physiology.

Evaluation of hemodynamic changes during laparoscopic cholecystectomy by transthoracic echocardiography

Background and Aims:

The purpose of this study was to prospectively examine the effects of pneumoperitoneum and the reverse Trendelenburg position on cardiac hemodynamics during laparoscopic cholecystectomy using transthoracic echocardiography (TTE).

Material and Methods:

In this prospective observational study, after institutional review board clearance, forty patients of either sex of ASA I-II status undergoing laparoscopic cholecystectomy were enrolled in the study. Changes in cardiac output, stroke volume, and ejection fraction were recorded using TTE at different time intervals: Preoperatively, before creation of pneumoperitoneum, 5 min after creation of pneumoperitoneum, and 5 min after setting the operative reverse Trendelenburg position with legs at the level of the hips. All statistical analyses were performed using the statistical program SPSS version 16 and P value less than 0.05 was considered as statistically significant. Data were examined using mixed analysis of variance (ANOVA) followed by post hoc Bonferroni correction.

Results:

There was significant fall in cardiac output (CO) (45%, P < 0.001), stroke volume (SV) (42%, P < 0.001), and ejection fraction (EF) (31.8% change, P < 0.001) after creation of pneumoperitoneum with significant rise in MAP (11%, P < 0.001). But with reverse Trendelenburg position, there was a significant improvement of CO (30%), SV (28%), and EF (21% change) in comparison to values after pneumoperitoneum, but still remained below baseline. There was no change in heart rate at different time intervals. There was no significant difference in hemodynamics between ASA I and II patients.

Conclusion:

Patients undergoing laparoscopic cholecystectomy undergo significant hemodynamic changes after pneumoperitoneum and reverse Trendelenburg position.

Alterations in Plasma Oxidative Stress Markers After Laparoscopic Operations of the Upper and Lower Abdomen

The patient’s position during laparoscopic surgery can have a clinically relevant effect on lower limb and splanchnic circulation; this factor has not yet been investigated with respect to oxidative stress markers. In order to assess this effect, a prospective clinical trial was designed wherein 2 groups of patients were studied. In group A, 15 patients underwent upper abdominal nonhepatobiliary operations (13 modified Nissen fundoplications and 2 Taylor vagotomies) in the head-up position. In group B, 15 patients underwent lower abdominal operations (10 laparoscopic colectomies and 5 inguinal hernia repairs) in the head-down position. The pneumoperitoneum was maintained at 14 mm Hg in all cases. Plasma concentrations of thiobarbituric-acid reactive substances (TBARS), a marker of lipid peroxidation, plasma total antioxidant status (TAS), and serum uric acid concentrations were measured preoperatively, 5 minutes after deflation of the pneumoperitoneum, and 24 hours postoperatively. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) serum activities were measured preoperatively and 24 hours postoperatively. In group A, there was a significant increase in TBARS levels (p<0.005) immediately after deflation of the pneumoperitoneum and a significant decrease in TAS and uric acid levels (p<0.005) in the first postoperative day. There was also a significant postoperative elevation in both ALT and AST activities (p<0.001). In group B, no significant increase was found in postoperative TBARS or transaminase levels. TAS and uric acid levels decreased significantly in the first postoperative day (p<0.05) and (p<0.005, respectively). In conclusion, these results show that a combination of pneumoperitoneum and the head-up position causes significant increase in lipid peroxidation, decrease in plasma TAS, and increase in transaminases. The mechanism responsible for these events could be the low-flow ischemia-reperfusion syndrome induced by the pneumoperitoneum and aggravated by the head-up position.

Hemodynamic effect and safety of intermittent sequential pneumatic compression leg sleeves in patients with congestive heart failure

BACKGROUND

Pneumatic leg sleeves are widely used after prolonged operations for prevention of venous stasis. In healthy volunteers they increase cardiac function. We evaluated the hemodynamic effects and safety of intermittent sequential pneumatic compression (ISPC) leg sleeves in patients with chronic congestive heart failure (CHF).

METHODS AND RESULTS

We studied 19 patients with systolic left ventricular dysfunction and CHF. ISPC leg sleeves, each with 10 air cells, were operated by a computerized compressor, exerting 2 cycles/min. Hemodynamic and echocardiographic parameters were measured before, during, and after ISPC activation. The baseline mean left ventricular ejection fraction was 29 ± 9.2%, median 32%, range 10%-40%. Cardiac output (from 4.26 to 4.83 L/min; P = .008) and stroke volume (from 56.1 to 63.5 mL; P = .029) increased significantly after ISPC activation, without a reciprocal increase in heart rate, and declined after sleeve deactivation. Systemic vascular resistance (SVR) decreased significantly (from 1,520 to 1,216 dyne-s/cm5; P = .0005), and remained lower than the baseline level throughout the study. There was no detrimental effect on diastolic function and no adverse clinical events, despite increased pulmonary venous return.

CONCLUSIONS

ISPC leg sleeves in patients with chronic CHF do not exacerbate symptoms and transiently improve cardiac output through an increase in stroke volume and a reduction in SVR.

Pneumatic compression devices during hemodialysis: a randomized crossover trial

BACKGROUND

Maintenance of central blood volume (CBV) is essential for hemodynamic stability during hemodialysis (HD), though preservation of CBV is poorly understood. Pneumatic compression devices (PCDs) during HD may help maintain CBV.

METHODS

We performed a randomized, crossover trial to determine the effect of PCDs on CBV during HD. Patients underwent two consecutive mid-week HD sessions, randomized to begin the first session either with or without PCDs [stratified by intradialytic hypotension (IDH)-prone status]. The primary outcome was change in CBV during HD. The secondary outcomes were change in other hemodynamic and volume status parameters.

RESULTS

Fifty-one patients (median age 65 years, 75% male, 22% IDH-prone) were randomized; forty-six completed the study. During HD, the median change in CBV for PCD and control sessions was -0.08 versus -0.05 L (P = 0.62). There was no difference in the change in cardiac output (CO) (-0.63 versus -0.49 L/min, P = 0.78) or systemic vascular resistance (SVR) (+1.30 versus +1.55 mmHg/L/min, P = 0.67) for PCDs versus control. Based on the bioimpedance measurements, patients were not volume overloaded pre-dialysis. There was a greater reduction in total body water (TBW) (-2.6 versus -2.3 L, P = 0.05) and intracellular fluid (ICF) volume (-1.3 versus -1.1 L, P = 0.03), and no difference in change in the extracellular fluid (ECF) volume (1.3 versus 1.2 L, P = 0.09) with PCDs versus control. Similar results were observed in IDH-prone patients.

CONCLUSIONS

Compared with standard of care, PCDs have no effect on intradialytic hemodynamic parameters, including CBV, although they may allow greater capacity for fluid removal. Further studies are required to better understand physiological and hemodynamic changes in patients during HD.

The effects of high-frequency jet ventilation (HFJV) on pneumoperitoneum-induced cardiovascular changes during laparoscopic surgery

BACKGROUND

Standard mechanical ventilation may cause adverse cardiovascular effects in addition to those already related to positive-pressure pneumoperitoneum (PP) during laparoscopic surgery. High-frequency jet ventilation (HFJV) is associated with much less airway pressure, with potentially less influence on venous return, thus potentially it may reduce those effects. The aim of this study was to evaluate the benefits of HFJV to reduce the adverse cardiovascular effects during laparoscopic cholecystectomy.

METHODS

We conducted a randomized prospective trial, comparing 12 patients undergoing elective laparoscopic cholecystectomy under conventional mechanical ventilation (control) with 13 similar subjects under HFJV (study). Both groups were categorized as ASA I-II and underwent total intravenous anesthesia. Cardiac functionality was continuously evaluated by analysis of arterial pressure wave changes (Edwards Flo-Trac sensor and Vigileo monitor).

RESULTS

There was no significant difference between both groups regarding age, gender, BMI, and general medical condition, as well as hemodynamic stability and blood gases throughout surgery. A significant reduction in cardiac output was noted in the control group under PP during the initiation of anti-Trendelenburg position (from 5.6 to 5.0 l/min, P = 0.049). A reciprocal change was observed regarding stroke volume. Such changes were not noticed under HFJV. Total peripheral resistance was significantly increased during PP, and heart rate was not significantly affected throughout surgery in both groups. Unexpectedly, we did not observe marked adverse hemodynamic changes in the control group during PP without position adjustment.

CONCLUSIONS

The use of HFJV in upper laparoscopic surgery can impede the adverse cardiovascular changes that usually occur during induction of PP. We also suggest that the use of total intravenous anesthesia (as used in our study) may also lessen the cardiovascular impairment during PP.

Antioxidant prophylaxis for cellular injury in ovarian surface epithelium resulting from CO₂ pneumoperitoneum in a laparoscopic rat model

OBJECTIVE

Selective cytoprotective functions of vitamin E, N-acetyl-L: -cysteine, and amifostine have been used as a preventer of ischemia injury by expelling the free oxygen radicals leading to stabilization of the cellular membranes. The purpose of this experimental study was to investigate the oxidative stress related to cellular injury in ovarian surface epithelium and the effect of prophylaxis with an anti-oxidant using laparoscopic rat model.

DESIGN

Laparoscopic rat model.

MATERIALS AND METHODS

Randomly allocated 40 Wistar Albino female rats have been used for the pneumoperitoneum model which was constituted to fix the intraabdominal pressure on 5 mmHg for 60 min. The antioxidants, vitamin E and NAC were given to rats 3 days before the operation and were applied for 30 days; amifostine was applied 30 min before the operation until after for 7 days. After abdominal desufflation, over biopsies were made on the 13th min, 24th h, and 7th and 30th days. By using of transmission electron microscopy, the damage on cells and organels were assessed and graded.

RESULTS

In ovarian surface epithelium, the apical surface specializations were affected in all groups except Vit E group:The microvilli were irregular and coarse and had disappeared in some places. Some cells were separated from the epithelium. In addition, mitochondria degeneration was observed in all group except Vit E.

CONCLUSIONS

In the early period of laparoscopy, reversible cellular damage occurs and this damage can be prevented by vitamin E.

The physiological impact of intermittent sequential pneumatic compression (ISPC) leg sleeves on cardiac activity

BACKGROUND

Pneumatic sleeves are widely used in surgery to prevent venous stasis and to improve cardiac function. The aim of this study was to assess the underlying cardiovascular mechanism induced by the activation of intermittent sequential pneumatic compression (ISPC) in healthy volunteers.

METHODS

Twenty male subjects underwent transthoracic echocardiographic and tissue Doppler imaging evaluation before and during the activation ISPC devices. Each patient served as his own control.

RESULTS

Following ISPC activation, there were significant increases in cardiac output (from 5.1 to 5.5 L/min, P < .05) and stroke volume (from 72 to 78 mL, P < .002), as well as ejection fraction, the velocity-time integral of aortic flow, and fractional shortening of the left ventricle. There was no increase in heart rate. Tissue Doppler imaging was compatible with normal cardiac responses. Total peripheral resistance was significantly reduced during ISPC activation.

CONCLUSIONS

The activation of ISPC devices in normal volunteers augmented cardiac output because of increased preload as well as decreased afterload.

Systematic review of oxidative stress associated with pneumoperitoneum

Background

There have been several reports of ischaemic complications after routine laparoscopy. The aim of this review was to investigate the relationship between this oxidative stress and pneumoperitoneum.

Methods

Medline, Medline in-process, The Cochrane Library, PubMed and EMBASE were searched for papers on oxidative stress and pneumoperitoneum, from 1947 to March 2008 with no language restriction or restriction on trial design. Papers that did not investigate pneumoperitoneum as a causative factor, or did not report outcome measures related to oxidative stress, were excluded.

Results

A total of 73 relevant papers were identified: 36 animal studies, 21 human clinical trials, nine case reports, five review articles and two comments. Pneumoperitoneum causes a reduction in splanchnic blood flow, resulting in biochemical evidence of oxidative stress in a pressure- and time-dependent manner. There is evidence that the use of carbon dioxide for insufflation is contributory. Several measures proposed to minimize the oxidative stress have shown promise in animal studies, but few have been evaluated in the clinical setting.

Conclusion

There is an increasing body of evidence, mainly from animal studies, that pneumoperitoneum decreases splanchnic perfusion with resulting oxidative stress. It is now appropriate to investigate the clinical significance of pneumoperitoneum-associated oxidative stress.

Systemic hemodynamic effects of sequential pneumatic compression of the lower limbs: a prospective study in healthy volunteers

STUDY OBJECTIVE

To evaluate the effects on systemic hemodynamics of sequential pneumatic compression of the lower limbs in healthy volunteers.

DESIGN

Prospective, self-controlled, volunteer study.

SETTING

University teaching hospital.

PATIENTS

11 healthy volunteers, aged 25 +/- 1.3 years.

INTERVENTIONS AND MEASUREMENTS

After volunteers underwent a 6-hour period of fasting and 15 minutes of rest in the supine position, baseline systemic hemodynamics were assessed using transthoracic electrical bioimpedance. Peripheral venous pressure was measured using a 16-gauge intravenous cannula inserted in the forearm and connected to a pressure monitor. Then sequential pneumatic compression of the lower limbs was activated for a 30-minute period, and systemic hemodynamic measurements were repeated. In each volunteer, measurements were repeated twice in two consecutive days, and average values were calculated for each volunteer.

MAIN RESULTS

After activation of sequential pneumatic compression of the lower limbs, mean arterial blood pressure increased from 90 mmHg (79-107 mmHg) to 95 mmHg (79-129 mmHg) (P = 0.02), whereas heart rate decreased from 79 bpm (51-94 bpm) to 75 bpm (53-90 bpm) (P = 0.02). This was associated with a significant increase in peripheral vascular resistance index (from 545 [440-1066] to 613 [369-1280] dynes s cm(-5) m(-2) [P = 0.013]) and reduction in cardiac index (from 3.4 [2.7- 4.5] to 3.2 [2.5-4.0] L/min per m2 [P = 0.034]).

CONCLUSIONS

The application of sequential pneumatic compression to the lower limbs is associated with minor increases in mean arterial blood pressure, with moderate reduction of cardiac output and heart rate.

The Effect of Negative Pressure Therapy on the Femoral Vein Blood Flow and Wall Structure

Negative pressure therapy has been recently used for managing lymphatic or infective groin complications. The aim of this study was to investigate any possible association between application of negative pressure therapy in the groin area and deep-vein thrombosis. Acute surgical wounds were created at the inguinal areas in 7 pigs. Different negative pressures ranging from −50 to −200 mmHg were applied directly over the femoral vessels, and blood flow alterations were studied using a Doppler ultrasound. Femoral vein specimens were also removed for histological examination after 12 hours of therapy. It has been demonstrated that negative pressure therapy does not significantly alter the baseline lower limb venous return. Histology demonstrated several changes, which are associated with vein thrombogenesis. The hemodynamic and pathological findings still leave a potential for thrombogenic effects of negative pressure therapy and warrant care to protect the femoral veins, with the use of thrombosis prophylaxis measures.

Intermittent pneumatic sequential compression of the lower extremities restores the cerebral oxygen saturation during laparoscopic cholecystectomy

BACKGROUND

Pneumoperitoneum causes intracranial pressure elevation and blood stasis at lower extremities. This study investigates cerebral oxygen saturation changes during laparoscopy and the effects of intermittent sequential compression (ISC) of the lower extremities in patients during elective laparoscopic cholecystectomy.

PATIENTS AND METHOD

Sixty patients were randomly divided into two groups according to the application of ISC to the lower extremities. Group I served as control group whereas ISC was applied to group II. Cerebral oxygen saturation, peripheral blood oxygen saturation, heart rate, mean blood pressure, and associated changes have been recorded during the operation.

RESULTS

Peripheral blood oxygen saturation and mean blood pressure values did not change significantly after pneumoperitoneum. Cerebral oxygen saturation levels of the group II patients were higher in than the group I patients and the difference between the groups was statistically significant (p = 0.0001). The difference became more prominent following the 35(th) minute of the operation. Mean heart rate of the patients in group II was lower than the patients in group I and the difference was also statistically significant (p = 0.0001).

CONCLUSION

In this study, it was found that the decrease in cerebral oxygen saturation was recovered with ISC application. This simple and reliable technique helps to restore cerebral oxygen saturation levels while increasing blood return from the lower extremities.

Validation and reduction of the oxidative stress following laparoscopic operations: a prospective randomized controlled study

OBJECTIVE

To validate ischemia-reperfusion mechanism during laparoscopic cholecystectomy, and to assess the reduction of oxidative stress by an intermittent sequential pneumatic compression (ISPC) device.

SUMMARY BACKGROUND

Increased intraperitoneal pressure during laparoscopic operations may lead to decreased cardiac output and visceral perfusion, and possible ischemia-reperfusion effects. Using the ISPC device was shown to improve cardiac output and visceral perfusion during pneumoperitoneum (PP).

METHODS

Twenty patients undergoing elective laparoscopic cholecystectomy were enrolled in a randomized prospective controlled study and divided into 2 groups: 1) study group (10 patients), activation of ISPC together with creation of PP; and 2) control group, without ISPC. Lipid peroxidation and glutathione levels (as indicators of oxidative stress) as well as liver and renal function tests, were measured before and at the end of PP, and again at 30 minutes, 4 hours, and 24 hours afterward, together with hemodynamic and respiratory parameters.

RESULTS

There was no significant difference between both groups concerning liver enzymes and bilirubin, nor in hemodynamic parameters. In the control group, increased lipid peroxide levels were noted 4 hours after PP termination, in comparison to pre-PP levels (590.4-649.2 mmol/L, P = 0.002). In the study group (ISPC), such changes were not inspected. Decreased total glutathione levels were noted in the control group, 30 minutes following CO2 evacuation.

CONCLUSIONS

Our study validates the ischemia-reperfusion mechanism following laparoscopic surgery. The use of an ISPC device decreased the oxidative stress (secondary to relative ischemia-reperfusion insult) following PP, probably due to improved cardiac output and visceral perfusion.

Hypovolemia after traditional preoperative care in patients undergoing colonic surgery is underrepresented in conventional hemodynamic monitoring

BACKGROUND AND AIMS

Hypovolemia after bowel preparation as well as capnoperitoneum (CP) may compromise hemodynamic function during laparoscopic colonic surgery. A fall in arterial pressure after induction of anesthesia is often answered by generous fluid administration, which might impair "fast-track" rehabilitation. Intraoperative assessment of the needed infusion volume is difficult because of a lack of data regarding the volume status in these patients.

PATIENTS AND METHODS

Nineteen patients scheduled for laparoscopic colonic surgery after bowel preparation were prospectively monitored using the PULSION COLD Z-021 system and central venous catheter. Intrathoracic blood volume index (ITBVI), mean arterial pressure (MAP), cardiac index (CI), central venous pressure (CVP), and heart rate (HR) were measured after induction of anesthesia (M1), during CP in head-down position with an intraabdominal pressure (IAP) of 20 mmHg (M2) and 12 mmHg (M3).

RESULTS

Although MAP (87 mmHg), HR (64 min(-1)), and CVP (8 mmHg) were within normal ranges at the induction of surgery, ITBVI (834 ml m(-2)), and CI (2.66 l m(-2)) were decreased, indicating a relative hypovolemia. CP with 12 mmHg increased ITBVI (p<0.05) and CI (p<0.01), while an IAP of 20 mmHg reduced CI (p<0.05) compared to 12 mmHg (M3). Mean infusion during the measurements was 1,355 ml.

CONCLUSION

Combination of CP with 12 mmHg, head-down position, and infusion of 1,500 ml fluids compensated relative hypovolemia during colonic surgery. With conventional monitoring, intravascular volume status might be underestimated after traditional preoperative care.

Conversions during laparoscopic cholecystectomy: risk factors and effects on patient outcome

In view of the substantial, at times conflicting, literature on conversion to open surgery during laparoscopic cholecystectomy (LC), we have considered it timely to review the subject to identify the risk factors for conversion and its consequences. The review is based on a complete literature search covering the period 1990 to 2005. The search identified 109 publications on the subject: 68 retrospective series, 16 prospective nonrandomized studies, 8 prospective randomized clinical trials, 5 prospective case-controlled studies, 5 reviews and 7 others (3 observational, 2 population-based studies, 1 national survey, and 1 editorial). As the majority of reported studies are retrospective, firm conclusions cannot be reached. Single factors that appear to be important include male gender, extreme old age, morbid obesity, cirrhosis, previous upper abdominal surgery, severe/advanced acute and chronic disease, and emergency LC. The combination of patient- and disease-related risk factors increases the conversion risk. In the training of residents, the number of cases needed for reaching proficiency exceeds 200 cases. The value of predictive scoring systems is important in the selection of cases for resident training. Conversion exerts adverse effects on operating time, postoperative morbidity, and hospital costs, especially when it is enforced. There appears to be no absolute contraindication to LC that is agreed upon by all. There is consensus on certain individual risk factors and their additive effect on the likelihood of conversion. Predictive systems based on these factors appear to be useful in selection of cases for resident training.

Cardiac Function During Intraperitoneal CO2 Insufflation for Aortic Surgery: A Transesophageal Echocardiographic Study

The effect of laparoscopy on cardiac function is controversial. We hypothesized that cardiac dysfunction related to increased afterload could be predominant in patients undergoing elective abdominal aortic repair. To test this hypothesis, we conducted a transesophageal echocardiographic study in 15 patients during laparoscopic aortic surgery. We systematically assessed left ventricular (LV) and right ventricular (RV) functions. Measurements were obtained in the supine position without pneumoperitoneum and with an intraabdominal pressure of 14 mm Hg. Then, patients were turned to the right lateral position without pneumoperitoneum and intraabdominal pressure was increased to 7 mm Hg and to 14 mm Hg. Pneumoperitoneum induced a 25% arterial blood pressure increase and a 38% increase in LV systolic wall stress. A 25% decrease in LV ejection fraction and an 18% decrease in LV stroke volume were observed, associated with an increase in LV end-systolic volume. LV diastolic function impairment was observed without change in LV end-diastolic volume. Respiratory alterations in superior vena cava diameter were never observed, suggesting that volume status remained optimal. Respiratory changes in RV stroke volume were increased according to intraabdominal pressure and body position, reflecting an increase in RV afterload. In conclusion, peritoneal CO2 insufflation in patients scheduled for laparoscopic aortic surgery could impair LV and RV systolic functions as a consequence of increased afterload.

Laparoscopy-Associated Portal Vein Thrombosis: Description of an Evolving Clinical Syndrome

Several cases of portal vein thrombosis following laparoscopic procedures have been reported over the past few years. To date, no formal description of this phenomenon has been provided. In this paper, we summarize and analyze the features of the 4 reported cases to date as well as a fifth case encountered at our institution. The probable causes of this complication include changes in coagulation status, splanchnic hemodynamics, and portal venous blood flow, all of which may be related to carbon dioxide absorption and increased intra-abdominal pressure. The recognition of this phenomenon and its management are discussed. A review of the relevant literature is provided.

Systematic evaluation of different approaches for minimizing hemodynamic changes during pneumoperitoneum

BACKGROUND

Capnoperitoneum (CP) compromises hemodynamic function during laparoscopy. Three therapeutic concepts were evaluated with an aim to minimize the hemodynamic reaction to CP: First, a controlled increase of intrathoracic blood volume (ITBV) by intravenous fluids; second, partially reduced sympathetic activity by the beta1-blocker esmolol; and third, a decrease in mean arterial pressure (MAP) by the vasodilator sodium nitroprusside.

METHODS

For this study, 43 pigs were assigned to treatment with fluid and sodium nitroprusside (group A) or with esmolol (group B). In both groups, the pigs were assigned to head-up, head-down, or supine position, resulting in three different subgroups. Invasive hemodynamic monitoring was established including left heart catheter and cardiac oxygen lung water determination (COLD) measurements. Measurements were documented before CP with the animals in supine position, after induction of a 14-mmHg CP with the animals in each body position, after a 10% reduction in MAP by vasodilation, and after an increase in ITBV of about 30% by infusion of 6% hydroxyethylstarch solution.

RESULTS

Increasing ITBV improved hemodynamic function in all body positions during CP. Esmolol reduced cardiac output and myocardial contractility. Sodium nitroprusside did not improve hemodynamic function in any body position.

CONCLUSIONS

Optimizing volume load is effective for minimizing hemodynamic changes during CP in the head-up and in head-down positions. In general, beta(1)-blockers cannot be recommended because they might additionally compromise myocardial contractility and suppress compensatory reaction of the sympathetic nerve system. Vasodilation has not improved hemodynamic parameters during CP.

La cirugía laparoscópica en Europa: ¿hacia dónde vamos?

The most important factors that have facilitated the development of laparoscopic surgery (LS) are technological innovations and the vision of a small number of surgeons who took advantage of these advances. There are few surgical innovations that have stimulated such controversies and concerns and have raised so many medico-legal issues as LS. Although much progress has been made in LS, some important controversies remain unresolved, which are reviewed in the present article: 1. Evolution of the laparoscopic approach: total laparoscopic approach through positive-pressure capnoperitoneum, gasless laparoscopy, hand-assisted laparoscopy, and laparoscopy-assisted surgery. 2. Classification of current instrumental technology in laparoscopic surgery: a) facilitating instruments (high-power ultrasonic dissection systems); b) enabling instruments (endostapling and linear dissection devices), and c) complementary instruments: the Da Vinci robotic system. 3. Current laparoscopic surgical practice: a) interventions that definitively improve the patient's outcome (diagnostic and staging laparoscopy, cholecystectomy, adrenalectomy, splenectomy, antireflux surgery, cardiomyotomy, bariatric surgery, laparoscopic colon surgery, living donor nephrectomy); b) interventions that seem to be useful to the patient (distal pancreatic surgery, laparoscopic left hepatic resection, gastric and esophageal resections, hernioplasty), and c) interventions with uncertain benefit (right hepatectomy, pancreatoduodenectomy). 4. Future lines of development: video monitors in laparoscopic surgery, endoluminal surgery, robotic surgery, and finally, 5. Problems faced by laparoscopic surgery: quality guarantees in laparoscopic surgery, training the future laparoscopic generation, and allocation of sufficient material and human resources to laparoscopic surgery and its subspecialties.

Laparoscopic surgery: current status, issues and future developments

Laparoscopic surgery has come a long way since its introduction two decades ago. In essence it represents a new era of technology-dependent surgical interventions, and to some extent its future progress depends on the growth of interventional technologies and devices (facilitative, enabling and additive). Laparoscopic surgery has had a significant impact on all surgical disciplines and is now firmly embedded in routine surgical practice. There remain, however, several outstanding issues that need to be addressed. These concern mainly quality assurance, training, resource allocation, assessment of competence and tiers of laparoscopic surgical practice in line with the changing situation facing the next generation of surgeons.

Randomized clinical trial of the effect of pneumoperitoneum on cardiac function and haemodynamics during laparoscopic cholecystectomy

BACKGROUND

Conventional laparoscopic cholecystectomy (CLC) with carbon dioxide pneumoperitoneum may cause major cardiovascular changes. The aim of this study was to evaluate the effect of carbon dioxide pneumoperitoneum and positional changes on haemodynamics and cardiac function in patients assigned randomly to CLC or gasless laparoscopic cholecystectomy (GLC).

METHODS

Fifty patients with American Society of Anesthesiologists physical status I and II were randomly allocated to CLC (28 patients) or GLC (22). Left ventricular end-diastolic and end-systolic diameters, fractional shortening and cardiac output were determined by transoesophageal echocardiography. Measurements were performed before (phase 1) and 10 and 30 min (phases 2 and 3 respectively) after pneumoperitoneum or abdominal wall traction, and after desufflation or release of abdominal wall traction (phase 4) in supine, Trendelenburg and reverse Trendelenburg positions.

RESULTS

Mean diastolic diameter, systolic diameter, mean arterial pressure and heart rate were significantly higher, and fractional shortening was significantly lower, with carbon dioxide pneumoperitoneum than with the gasless procedure during phases 2 and 3. There were no significant differences in cardiac output between the two groups.

CONCLUSION

Carbon dioxide pneumoperitoneum was associated with increased preload and afterload in patients undergoing laparoscopic cholecystecomy. It also decreased heart performance (fractional shortening), but did not affect cardiac output.

Improving the adverse changes in cardiac autonomic nervous control during laparoscopic surgery, using an intermittent sequential pneumatic compression device

BACKGROUND

The creation of positive pressure pneumoperitoneum (PP) may lead to adverse cardiovascular effects during laparoscopic operations. It can also lead to increased sympathetic cardiac activity, that might have serious consequences. We hypothesized that by reversing the hemodynamic effects, the use of intermittent sequential pneumatic compression device (Lympha-press) on the lower extremities would lead to improved cardiac autonomic control.

METHODS

This was a prospective cohort study, in which patients served as their own control. Fifteen patients without cardiorespiratory disease undergoing elective laparoscopic cholecystectomy were enrolled prospectively. The activity of the cardiac autonomic nervous system was evaluated by using spectral analysis of heart rate variability, with the Del Mar Avionics 363 (Irvine, California), based on the fast Fourier transformation. The Lympha-press was manipulated several minutes after induction of PP. In each frequency band we measured and compared the power values during anesthesia against those of PP, as well as those of PP against those recorded during activation of Lympha-press.

RESULTS

Creation of PP caused increased sympathetic activity, as was manifested by increased power of the low frequency band. Manipulation of the Lympha-Press compression device caused increased parasympathetic activity, as was evident by significant increased power of the high frequency band in all patients.

CONCLUSIONS

Using an intermittent sequential pneumatic compression device during laparoscopic cholecystectomy may improve cardiac autonomic control by enhancing protective parasympathetic activity. That may have clinical significance, especially in patients suffering from cardiac disease, by improving heart rate variability and elevating the threshold of the occurrence of ventricular arrhythmia.