A Comparison of Gasless Mechanical and Conventional Carbon Dioxide Pneumoperitoneum Methods for Laparoscopic Cholecystectomy

Urinary oxygen tension and its role in predicting acute kidney injury: A narrative review

Acute kidney injury occurs frequently in the perioperative setting. The renal medulla often endures hypoxia or hypoperfusion and is susceptible to the imbalance between oxygen supply and demand due to the nature of renal blood flow distribution and metabolic rate in the kidney. The current available evidence demonstrated that the urine oxygen pressure is proportional to the variations of renal medullary tissue oxygen pressure. Thus, urine oxygenation can be a candidate for reflecting the change of oxygen in the renal medulla. In this review, we discuss the basic physiology of acute kidney injury, as well as techniques for monitoring urine oxygen tension, confounding factors affecting the reliable measurement of urine oxygen tension, and its clinical use, highlighting its potential role in early detection and prevention of acute kidney injury.

Pneumoperitoneum and Acute Kidney Injury-An Integrative Clinical Concept Review

An increased intraabdominal pressure, particularly when occurring during periods of hemodynamic instability or fluid overload, is regarded as a major contributor to acute kidney injury (AKI) in intensive care units. During abdominal laparoscopic procedures, intraoperative insufflation pressures up to 15 mmHg are applied, to enable visualization and surgical manipulation but with the potential to compromise net renal perfusion. Despite the widely acknowledged renal arterial autoregulation, net arterial perfusion pressure is known to be narrow, and the effective renal medullary perfusion is disproportionately impacted by venous and lymphatic congestion. At present, the potential risk factors, mitigators and risk-stratification of AKI during surgical pneumoperitoneum formation received relatively limited attention among nephrologists and represent an opportunity to look beyond mere blood pressure and intake-output balances. Careful charting and reporting duration and extent of surgical pneumoperitoneum represents an opportunity for anesthesia teams to better communicate intraoperative factors affecting renal outcomes for the postoperative clinical teams. In this current article, the authors are integrating preclinical data and clinical experience to provide a better understanding to optimize renal perfusion during surgeries. Future studies should carefully consider intrabdominal insufflation pressure as a key variable when assessing outcomes and blood pressure goals in these settings.

Pneumoperitoneum in Veterinary Laparoscopy: A Review

Objective: To review the effects of carbon dioxide pneumoperitoneum during laparoscopy, evaluate alternative techniques to establishing a working space and compare this to current recommendations in veterinary surgery. Study Design: Literature review. Sample Population: 92 peer-reviewed articles. Methods: An electronic database search identified human and veterinary literature on the effects of pneumoperitoneum (carbon dioxide insufflation for laparoscopy) and alternatives with a focus on adaptation to the veterinary field. Results: Laparoscopy is the preferred surgical approach for many human and several veterinary procedures due to the lower morbidity associated with minimally invasive surgery, compared to laparotomy. The establishment of a pneumoperitoneum with a gas most commonly facilitates a working space. Carbon dioxide is the preferred gas for insufflation as it is inert, inexpensive, noncombustible, colorless, excreted by the lungs and highly soluble in water. Detrimental side effects such as acidosis, hypercapnia, reduction in cardiac output, decreased pulmonary compliance, hypothermia and post-operative pain have been associated with a pneumoperitoneum established with CO₂ insufflation. As such alternatives have been suggested such as helium, nitrous oxide, warmed and humidified carbon dioxide and gasless laparoscopy. None of these alternatives have found a consistent benefit over standard carbon dioxide insufflation. Conclusions: The physiologic alterations seen with CO₂ insufflation at the current recommended intra-abdominal pressures are mild and of transient duration. Clinical Significance: The current recommendations in veterinary laparoscopy for a pneumoperitoneum using carbon dioxide appear to be safe and effective.

Anesthetic considerations for patients with esophageal achalasia undergoing peroral endoscopic myotomy: a retrospective case series review

PURPOSE

Peroral endoscopic myotomy (POEM) is a novel technique for treating esophageal achalasia. During POEM, carbon dioxide (CO₂) is insufflated to aid surgical dissection, but it may inadvertently track into surrounding tissues, causing systemic CO₂ uptake and tension capnoperitoneum. This in turn may affect cardiorespiratory function. This study quantified these cardiorespiratory effects and treatment by hyperventilation and percutaneous abdominal needle decompression (PND).

METHODS

One hundred and seventy-three consecutive patients who underwent POEM were included in this four-year retrospective study. Procedure-related changes in peak inspiratory pressure (p_max), end-tidal CO₂ levels (etCO₂), minute ventilation (MV), mean arterial pressure (MAP), and heart rate (HR) were analyzed. We also quantified the impact of PND on these cardiorespiratory parameters.

RESULTS

During the endoscopic procedure, cardiorespiratory parameters increased from baseline: p_max 15.1 (4.5) vs 19.8 (4.7) cm H₂O; etCO₂ 4.5 (0.4) vs 5.5 (0.9) kPa [34.0 (2.9) vs 41.6 (6.9) mmHg]; MAP 73.9 (9.7) vs 99.3 (15.2) mmHg; HR 67.6 (12.4) vs 85.3 (16.4) min^-1 (P < 0.001 for each). Hyperventilation [MV 5.9 (1.2) vs 9.0 (1.8) L·min^-1, P < 0.001] was applied to counteract iatrogenic hypercapnia. Individuals with tension capnoperitoneum treated with PND (n = 55) had higher peak p_max values [22.8 (5.7) vs 18.4 (3.3) cm H₂O, P < 0.001] than patients who did not require PND. After PND, p_max [22.8 (5.7) vs 19.9 (4.3) cm H₂O, P = 0.045] and MAP [98.2 (16.3) vs 88.6 (11.8) mmHg, P = 0.013] decreased. Adverse events included pneumothorax (n = 1), transient myocardial ischemia (n = 1), and subcutaneous emphysema (n = 49). The latter precluded immediate extubation in eight cases. Postanesthesia care unit (PACU) stay was longer in individuals with subcutaneous emphysema than in those without [74.9 min (34.5) vs 61.5 (26.8 min), P = 0.007].

CONCLUSION

Carbon dioxide insufflation during POEM produces systemic CO₂ uptake and increased intra-abdominal pressure. Changes in cardiorespiratory parameters include increased p_max, etCO₂, MAP, and HR. Hyperventilation and PND help mitigate some of these changes. Subcutaneous emphysema is common and may delay extubation and prolong PACU stay.

Urinary oxygen tension: a clinical window on the health of the renal medulla?

We describe the determinants of urinary oxygen tension (Po2) and the potential for use of urinary Po2 as a “physiological biomarker” of the risk of acute kidney injury (AKI) in hospital settings. We also identify knowledge gaps required for clinical translation of bedside monitoring of urinary Po2. Hypoxia in the renal medulla is a hallmark of AKI of diverse etiology. Urine in the collecting ducts would be expected to equilibrate with the tissue Po2 of the inner medulla. Accordingly, the Po2 of urine in the renal pelvis changes in response to stimuli that would be expected to alter oxygenation of the renal medulla. Oxygen exchange across the walls of the ureter and bladder will confound measurement of the Po2 of bladder urine. Nevertheless, the Po2 of bladder urine also changes in response to stimuli that would be expected to alter renal medullary oxygenation. If confounding influences can be understood, urinary bladder Po2 may provide prognostically useful information, including for prediction of AKI after cardiopulmonary bypass surgery. To translate bedside monitoring of urinary Po2 into the clinical setting, we require 1) a more detailed knowledge of the relationship between renal medullary oxygenation and the Po2 of pelvic urine under physiological and pathophysiological conditions; 2) a quantitative understanding of the impact of oxygen transport across the ureteric epithelium on urinary Po2 measured from the bladder; and 3) a simple, robust medical device that can be introduced into the bladder via a standard catheter to provide reliable and continuous measurement of urinary Po2.

Abdominal lift for laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy (key-hole removal of the gallbladder) is now the most often used method for treatment of symptomatic gallstones. Several cardiopulmonary changes (decreased cardiac output, pulmonary compliance, and increased peak airway pressure) occur during pneumoperitoneum, which is now introduced to allow laparoscopic cholecystectomy. These cardiopulmonary changes may not be tolerated in individuals with poor cardiopulmonary reserve.

OBJECTIVES

To assess the benefits and harms of abdominal wall lift compared to pneumoperitoneum in patients undergoing laparoscopic cholecystectomy.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until February 2013.

SELECTION CRITERIA

We included all randomised clinical trials comparing abdominal wall lift (with or without pneumoperitoneum) versus pneumoperitoneum.

DATA COLLECTION AND ANALYSIS

We calculated the risk ratio (RR), rate ratio (RaR), or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis with both the fixed-effect and the random-effects models using the Review Manager (RevMan) software.

MAIN RESULTS

For abdominal wall lift with pneumoperitoneum versus pneumoperitoneum, a total of 130 participants (all with low anaesthetic risk) scheduled for elective laparoscopic cholecystectomy were randomised in five trials to abdominal wall lift with pneumoperitoneum (n = 53) versus pneumoperitoneum only (n = 52). One trial which included 25 people did not state the number of participants in each group. All five trials had a high risk of bias. There was no mortality or conversion to open cholecystectomy in any of the participants in the trials that reported these outcomes. There was no significant difference in the rate of serious adverse events between the two groups (two trials; 2/29 events (0.069 events per person) versus 2/29 events (0.069 events per person); rate ratio 1.00; 95% CI 0.17 to 5.77). None of the trials reported quality of life, the proportion of people discharged as day-patient laparoscopic cholecystectomies, or pain between four and eight hours after the operation. There was no significant difference in the operating time between the two groups (four trials; 53 participants versus 54 participants; 13.39 minutes longer (95% CI 2.73 less to 29.51 minutes longer) in the abdominal wall lift with pneumoperitoneum group and 100 minutes in the pneumoperitoneum group).For abdominal wall lift versus pneumoperitoneum, a total of 774 participants (the majority with low anaesthetic risk) scheduled for elective laparoscopic cholecystectomy were randomised in 18 trials to abdominal wall lift without pneumoperitoneum (n = 332) versus pneumoperitoneum (n = 358). One trial which included 84 people did not state the number in each group. All the trials had a high risk of bias. There was no mortality in any of the trials that reported this outcome. There was no significant difference in the proportion of participants with serious adverse events (six trials; 5/172 (weighted proportion 2.4%) versus 2/171 (1.2%); RR 2.01; 95% CI 0.52 to 7.80). There was no significant difference in the rate of serious adverse events between the two groups (three trials; 5/99 events (weighted number of events per person = 0.346 events) versus 2/99 events (0.020 events per person); rate ratio 1.73; 95% CI 0.35 to 8.61). None of the trials reported quality of life or pain between four and eight hours after the operation. There was no significant difference in the proportion of people who underwent conversion to open cholecystectomy (11 trials; 5/225 (weighted proportion 2.3%) versus 7/235 (3.0%); RR 0.76; 95% CI 0.26 to 2.21). The operating time was significantly longer in the abdominal wall lift group than in the pneumoperitoneum group (16 trials; 6.87 minutes longer (95% CI 4.74 minutes to 9.00 minutes longer) in the abdominal wall lift group versus 75 minutes in the pneumoperitoneum group). There was no significant difference in the proportion of people discharged as laparoscopic cholecystectomy day-patients (two trials; 15/31 (weighted proportion 48.5%) versus 9/31 (29%); RR 1.67; 95% CI 0.85 to 3.26).

AUTHORS' CONCLUSIONS

Abdominal wall lift with or without pneumoperitoneum does not seem to offer an advantage over pneumoperitoneum in any of the patient-oriented outcomes for laparoscopic cholecystectomy in people with low anaesthetic risk. Hence it cannot be recommended routinely. The safety of abdominal wall lift is yet to be established. More research on the topic is needed because of the risk of bias in the included trials and because of the risk of type I and type II random errors due to the few participants included in the trials. Future trials should include people at higher anaesthetic risk. Furthermore, such trials should include blinded assessment of outcomes.

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.

A gasless laparoscopic technique of wide excision for gastric gastrointestinal stromal tumor versus open method

Background

Traditional open surgery for gastrointestinal stromal tumors (GIST) requires a long incision. Moreover, the gas-filling laparoscopic technique used in GIST surgery still has its limitations. Therefore, we developed a gasless laparoscopic (GL) surgery for GIST and compared it with traditional open surgery.

Methods

Between October 2007 and September 2009, 62 GIST patients in the National Taiwan University Hospital received wide excisions. Of these 62 patients, 30 underwent the new procedure (GL group) and 32 had open surgery (OS group). Preoperative and postoperative clinicopathologic characteristics were compared between the groups.

Results

There were no significant differences in preoperative characteristics or blood loss. However, the days to first flatus, postoperative hospital stay, wound length, white blood cell count at postoperative day one, and peak daily body temperature were all significantly improved in the GL group. Usage of postoperative analgesia on postoperative days one to five was also significantly lower in the GL group.

Conclusions

Wide-excision laparoscopy for gastric GIST can be performed more safely, more effectively, and with faster postoperative recovery using the gasless technique as compared with the open method. We, therefore, recommend this new surgical technique, which hybridizes the advantages of both the traditional open method and pure laparoscopic surgery.

Laparoscopic approach to acute abdomen from the Consensus Development Conference of the Società Italiana di Chirurgia Endoscopica e nuove tecnologie (SICE), Associazione Chirurghi Ospedalieri Italiani (ACOI), Società Italiana di Chirurgia (SIC), Società Italiana di Chirurgia d'Urgenza e del Trauma (SICUT), Società Italiana di Chirurgia nell'Ospedalità Privata (SICOP), and the European Association for Endoscopic Surgery (EAES)

BACKGROUND

In January 2010, the SICE (Italian Society of Endoscopic Surgery), under the auspices of the EAES, decided to revisit the clinical recommendations for the role of laparoscopy in abdominal emergencies in adults, with the primary intent being to update the 2006 EAES indications and supplement the existing guidelines on specific diseases.

METHODS

Other Italian surgical societies were invited into the Consensus to form a panel of 12 expert surgeons. In order to get a multidisciplinary panel, other stakeholders involved in abdominal emergencies were invited along with a patient's association. In November 2010, the panel met in Rome to discuss each chapter according to the Delphi method, producing key statements with a grade of recommendations followed by commentary to explain the rationale and the level of evidence behind the statements. Thereafter, the statements were presented to the Annual Congress of the EAES in June 2011.

RESULTS

A thorough literature review was necessary to assess whether the recommendations issued in 2006 are still current. In many cases new studies allowed us to better clarify some issues (such as for diverticulitis, small bowel obstruction, pancreatitis, hernias, trauma), to confirm the key role of laparoscopy (such as for cholecystitis, gynecological disorders, nonspecific abdominal pain, appendicitis), but occasionally previous strong recommendations have to be challenged after review of recent research (such as for perforated peptic ulcer).

CONCLUSIONS

Every surgeon has to develop his or her own approach, taking into account the clinical situation, her/his proficiency (and the experience of the team) with the various techniques, and the specific organizational setting in which she/he is working. This guideline has been developed bearing in mind that every surgeon could use the data reported to support her/his judgment.

Management of benign ovarian cysts by a novel, gasless, single-incision laparoscopic technique: keyless abdominal rope-lifting surgery (KARS)

BACKGROUND

To find the most efficacious method to minimize the side effects and maximize the advantages of laparoscopic surgery, this study aimed to define and document a gasless, single-incision abdominal access technique for the management of benign ovarian cysts.

METHODS

During a 1½ year period, 55 women underwent surgery for a benign ovarian cyst. Conventional carbon dioxide (CO(2)) laparoscopy was used for 33 of the women, and 22 of the women underwent a novel, gasless, single-incision laparoscopic surgery. An abdominal access pathway through a single intraabdominal incision was used to place transabdominal sutures that elevated the abdominal wall, and the operations were performed through the intra-umbilical entry without the use of trocars. Thus, the new technique was called keyless abdominal rope-lifting surgery (KARS). Two operative groups were compared to assess the feasibility of the new technique.

RESULTS

All the operations could be performed by KARS without conversion to CO(2) laparoscopy or laparotomy. However, for two patients in the conventional laparoscopy group, minilaparotomy had to be performed for tissue retrieval. Although the two techniques had many similar results, the total operative times and the abdominal access times in the KARS group were significantly longer than in the conventional laparoscopy group (p < 0.05). Simple oral analgesics were adequate for postoperative pain relief in both groups.

CONCLUSIONS

The KARS technique is a gasless, single-incision laparoscopic procedure that can be performed safely and effectively in terms of cosmesis, postoperative pain, and fertility preservation for the management of benign adnexal pathologies.

Abdominal lift for laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy (key-hole removal of the gallbladder) is now the most often used method for treatment of symptomatic gallstones. Several cardiopulmonary changes (decreased cardiac output, pulmonary compliance, and increased peak airway pressure) occur during pneumoperitoneum, which is now introduced to allow laparoscopic cholecystectomy. These cardiopulmonary changes may not be tolerated in individuals with poor cardiopulmonary reserve.

OBJECTIVES

To assess the benefits and harms of abdominal wall lift compared with pneumoperitoneum in patients undergoing laparoscopic cholecystectomy.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until January 2012.

SELECTION CRITERIA

We included all randomised clinical trials comparing abdominal wall lift (with or without pneumoperitoneum) versus pneumoperitoneum.

DATA COLLECTION AND ANALYSIS

We calculated the risk ratio (RR), rate ratio (RaR), or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis with both the fixed-effect and the random-effects models using RevMan software.

MAIN RESULTS

For abdominal wall lift with pneumoperitoneum versus pneumoperitoneum, a total of 156 participants (all with low anaesthetic risk) who underwent elective laparoscopic cholecystectomy were randomised in six trials to abdominal wall lift with pneumoperitoneum (n = 65) versus pneumoperitoneum only (n = 66). One trial which included 25 patients did not state the number of patients in each group. All six trials had a high risk of bias. There was no mortality or conversion to open cholecystectomy in any of the patients in the trials that reported these outcomes. There was no significant difference in the rate of serious adverse events between the two groups (2 trials; 2/29 events (0.069 events per patient) versus 2/29 events (0.069 events per patient); rate ratio 1.00; 95% CI 0.17 to 5.77). None of the trials reported quality of life, the proportion of patients discharged as day-patient laparoscopic cholecystectomies, or pain between four and eight hours after the operation. There was no significant difference in the operating time between the two groups (4 trials; 53 patients versus 54 patients; 13.39 minutes longer (2.73 less to 29.51 longer) in the abdominal wall lift with pneumoperitoneum group and 100 minutes in the pneumoperitoneum group).For abdominal wall lift versus pneumoperitoneum, a total of 774 participants (the majority with low anaesthetic risk) who underwent elective laparoscopic cholecystectomy were randomised in 18 trials to abdominal wall lift without pneumoperitoneum (n = 332) versus pneumoperitoneum (n = 358). One trial which included 84 patients did not state the number of patients in each group. All the trials had a high risk of bias. There was no mortality in any of the trials that reported this outcome. There was no significant difference in the rate of serious adverse events between the two groups (6 trials; 5/172 events (weighted number of events per patient = 0.020 events) versus 2/171 events (0.012 events per patient); rate ratio 1.73; 95% CI 0.35 to 8.61). None of the trials reported quality of life or pain between four and eight hours after the operation. There was no significant difference in the proportion of patients who underwent conversion to open cholecystectomy (11 trials; 5/225 (weighted proportion 2.3%) versus 7/235 (3.0%); RR 0.76; 95% CI 0.26 to 2.21). The operating time was significantly longer in the abdominal wall lift group than the pneumoperitoneum group (16 trials; 6.87 minutes longer (4.74 to 9.00 longer) in the abdominal wall lift group; 75 minutes in the pneumoperitoneum group). There was no significant difference in the proportion of patients who were discharged as day-patient laparoscopic cholecystectomy patients (2 trials; 15/31 (weighted proportion 48.5%) versus 9/31 (29%); RR 1.67; 95% CI 0.85 to 3.26).

AUTHORS' CONCLUSIONS

Abdominal wall lift does not seem to offer an advantage over pneumoperitoneum in any of the patient-oriented outcomes for laparoscopic cholecystectomy in patients with low anaesthetic risk. It may increase costs by increasing the operating time. Hence it cannot be recommended routinely. The safety of abdominal wall lift is yet to be established. More research on the topic is needed because of the risk of bias in the included trials and because of the risk of type I and type II random errors because of the few patients included in the trials. Such trials ought to include patients at higher anaesthetic risk. Furthermore, such trials ought to include blinded assessment of outcome measures.

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.

Magnesium sulphate attenuates arterial pressure increase during laparoscopic cholecystectomy

BACKGROUND

Magnesium is well known to inhibit catecholamine release and attenuate vasopressin-stimulated vasoconstriction. We investigated whether i.v. magnesium sulphate attenuates the haemodynamic stress responses to pneumoperitoneum by changing neurohumoral responses during laparoscopic cholecystectomy.

METHODS

Thirty-two patients undergoing laparoscopic cholecystectomy were randomly assigned to two groups; a control group was given saline, and a magnesium group received magnesium sulphate 50 mg kg(-1) immediately before pneumoperitoneum. Arterial pressure, heart rate, serum magnesium, plasma renin activity (PRA), and catecholamine, cortisol, and vasopressin levels were measured.

RESULTS

Systolic and diastolic arterial pressures were greater in the control group (P<0.05) than in the magnesium group at 10, 20, and 30 min post-pneumoperitoneum. Norepinephrine or epinephrine levels [pg ml(-1), mean (SD)] were higher in the control group than in the magnesium group at 5 [211 (37) vs 138 (18)] or 10 min [59 (19) vs 39 (9)] post-pneumoperitoneum, respectively (P<0.05). In the control group, vasopressin levels [pg ml(-1), mean (SD)] were higher compared with the magnesium group at 5 [64 (18) vs 35 (9), P<0.01] and 10 min [65 (18) vs 47 (11), P<0.05] post-pneumoperitoneum. There were no significant differences between the groups in PRA and cortisol levels.

CONCLUSIONS

I.V. magnesium sulphate before pneumoperitoneum attenuates arterial pressure increases during laparoscopic cholecystectomy. This attenuation is apparently related to reductions in the release of catecholamine, vasopressin, or both.

Hyper osmolality does not modulate natriuretic peptide concentration in patients after coronary artery surgery

BACKGROUND

The heart secretes natriuretic peptides (NPs) in response to myocardial stretch. Measuring NP concentrations is a helpful tool in guiding treatment. It has been suggested that sodium ion and hyperosmolality could affect NP excretion. If this is true, peri-operative NP measurements could be inconsistent when hypertonic solutions are used. With different osmolalities but equal volumes of hydroxyethyl starch (HES)--and hypertonic saline (HS)--infusions, this double-blinded study tested the hypothesis that osmolality modulates the excretion of NPs.

METHODS

Fifty coronary surgery patients were randomized to receive within 30 min 4 ml/kg either HS or HES post-operatively. Samples for analysis of atrial NP (ANP), brain NP (BNP), plasma and urine sodium and osmolality and urine oxygen tension were obtained before and 60 min after starting the infusions and on the first post-operative morning. The haemodynamic parameters were measured at the same time points.

RESULTS

Plasma osmolality and sodium increased only in the HS group. Changes in plasma BNP and ANP levels did not differ between the groups (P=0.212 and 0.356). There were no correlations between NP levels and osmolality or sodium at any time point. In the HS group, urine volume was higher (3295 vs. 2644 ml; P<0.05) and the need for furosemide treatment was less (0.4 vs. 3.8 mg; P<0.01) than in the HES group.

CONCLUSIONS

The absence of effects of plasma sodium content or hyperosmolality on NP release validates the value of NPs as a biomarker in peri-operative patients.

A simple clinical maneuver to reduce laparoscopy-induced shoulder pain: a randomized controlled trial

OBJECTIVE

To estimate the efficacy of a simple clinical maneuver that facilitates removal of residual abdominal carbon dioxide (CO2) after laparoscopic surgery to reduce shoulder pain.

METHODS

A total of 116 female outpatients who were scheduled for elective gynecologic laparoscopic surgery were randomly allocated to either the current standard (control group) or to additional efforts to remove residual CO2 at the end of surgery. In the control group, CO2 was removed by passive deflation of the abdominal cavity through the cannula. In the intervention group, CO2 was removed by means of Trendelenburg position (30 degrees) and a pulmonary recruitment maneuver consisting of five manual inflations of the lung. Postoperative shoulder pain was assessed before discharge and 12, 24, 36, and 48 hours later using a visual analog scale (VAS, 0-100). In addition, positional characteristics of the shoulder pain and incidence of postdischarge nausea and vomiting were recorded until 48 hours after discharge.

RESULTS

Pain scores in the control and intervention groups were 30.3+/-4.5 compared with 15.6+/-3.0, 25.7+/-4.7 compared with 10.8+/-2.4, and 21.7+/-4.3 compared with 9.1+/-2.5 at 12, 24 and 36 hours after discharge, respectively (all P<.05). The intervention reduced positional pain from 63% to 31% (P<.05) and the incidence of postoperative nausea and vomiting from 56.5% to 20.4% (P<.001).

CONCLUSION

This simple clinical maneuver at the end of surgery reduced shoulder pain as well as postoperative nausea and vomiting after laparoscopic surgery by more than half.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov, ClinicalTrials.gov, NCT00575237

LEVEL OF EVIDENCE

I.

Abdominal lift for laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy is the main method of treatment of symptomatic gallstones. Several cardiopulmonary changes (decreased cardiac output, pulmonary compliance, and increased peak airway pressure) occur during pneumoperitoneum. These changes may not be tolerated in individuals with poor cardiopulmonary reserve.

OBJECTIVES

To assess the benefits and harms of abdominal wall lift compared to pneumoperitoneum in patients undergoing laparoscopic cholecystectomy.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, EMBASE, and Science Citation IndexExpanded until January 2007.

SELECTION CRITERIA

We included all randomised clinical trials comparing abdominal wall lift (with or without pneumoperitoneum) and pneumoperitoneum.

DATA COLLECTION AND ANALYSIS

We calculated the relative risk (RR), weighted mean difference (WMD) or standardised mean difference (SMD) with 95% confidence intervals (CI) based on intention-to-treat analysis with both the fixed-effect and the random-effects model using RevMan Analysis.

MAIN RESULTS

Abdominal wall lift with pneumoperitoneum versus pneumoperitoneum. A total of 156 participants (all with low anaesthetic risk) who underwent elective laparoscopic cholecystectomy were randomised in six trials to abdominal wall lift with pneumoperitoneum (n = 65) versus pneumoperitoneum only (n = 66). One trial which included 25 patients did not state the number of patients in each group. All six trials were of high risk of bias. The cardiopulmonary changes were less in abdominal wall lift than pneumoperitoneum. There was no difference in the morbidity and pain between the groups. Abdominal wall lift versus pneumoperitoneum. A total of 550 participants (the majority with low anaesthetic risk) who underwent elective laparoscopic cholecystectomy were randomised in fourteen trials to abdominal wall lift without pneumoperitoneum (n = 268) versus pneumoperitoneum (n = 282). Two of these fourteen trials were of low risk of bias. The cardiopulmonary changes were less in abdominal wall lift than with pneumoperitoneum. There was no difference in the morbidity and pain between the groups. The operating time was prolonged in abdominal wall lift compared with pneumoperitoneum (WMD 7.74, 95% CI 1.37 to 14.12).

AUTHORS' CONCLUSIONS

(1) Abdominal wall lift seems safe and decreases the cardiopulmonary changes associated with laparoscopic cholecystectomy.(2) Abdominal wall lift does not seem to offer advantage over pneumoperitoneum in any of the patient-oriented outcomes for laparoscopic cholecystectomy in patients with low anaesthetic risk and may increase costs by increasing the operating time. Hence it cannot be recommended routinely. More research on the topic is needed.

[Comparative analysis about hemodynamic and renal blood flow effects during open versus laparoscopic nephrectomy. An experimental study]

BACKGROUND

The increase of intraabdominal pressure to 10 mmHg provokes a decrease of renal blood flow (RBF). Pneumoperitoneum during laparoscopic techniques with intra-abdominal pressure (IAP) to 15 mmHg, results in a decrease in RBF, urine output and glomerular filtration rate (GFR).

PURPOSE

Analyze the changes in RBF, urine output an GFR in a porcine experimental model during open vs laparoscopic nephrectomy.

MATERIALS AND METHODS

30 pigs (medium weigh= 22.6+3.2 Kg) were divided into two groups: Laparoscopic nephrectomy was performed using 15 pigs and open nephrectomy in 15 pigs, following a living donor nephrectomy autotransplantation model. Study parameters were urine volume and GFR baseline values, 30 and 60 minutes during nephrectomy. RBF was measured using an electromagnetic flow catheter around the main renal artery during the initial 60 minutes of nephrectomy.

RESULTS

The laparoscopic technique was associated with a significant reduction of RBF (80+2.7 vs 262+3 ml/min) (p<0.005), diuresis (42%) and GFR (38%), vs the open group.

CONCLUSIONS

Laparoscopic nephrectomy involves a significant reduction of RBF, GFR and diuresis, which is potentially transcendent in living donor nephrectomy and kidney transplantation.

Laparoscopic Exposure in Obese High-Risk Patients With Mechanical Displacement of the Abdominal Wall

BACKGROUND

Patients with morbid obesity or pulmonary disease are at a higher risk for complications during advanced laparoscopic procedures. Higher intraperitoneal carbon dioxide pressures required to elevate the pannus can negatively impact hemodynamic and respiratory parameters.

CASES

We describe a technique that uses a combination of a mechanical retractor and a Foley catheter inserted midway between the umbilicus and the pubic symphysis that assists in elevating the anterior abdominal wall. In 3 cases this technique allowed for a low-pressure pneumoperitoneum during advanced laparoscopic pelvic surgery, which resulted in improved hemodynamic parameters and pulmonary function in these high-risk patients.

CONCLUSION

The Foley Lap-Lift facilitated laparoscopy through mechanical abdominal wall elevation and allowed for a lower-pressure pneumoperitoneum. This technique is an addition to traditional operative laparoscopy in select high-risk patients.

Operative stress response and energy metabolism after laparoscopic cholecystectomy compared to open surgery

AIM: To determine the least invasive surgical procedure by comparing the levels of operative stress hormones, response-reactive protein (CRP) and rest energy expenditure (REE) after laparoscopic (LC) and open cholecystectomy (OC).

METHODS: Twenty-six consecutive patients with noncomplicated gallstones were randomized for LC (14) and OC (12). Plasma concentrations of somatotropin, insulin, cortisol and CRP were measured. The levels of REE were determined.

RESULTS: In the third postoperative day, the insulin levels were lower compared to that before operation (P < 0.05). In the first postoperative day, the levels of somatotropin and cortisol were higher in OC than those in LC. After operation the parameters of somatotropin, CRP and cortisol increased, compared to those in the preoperative period in the all patients (P < 0.05). In the all-postoperative days, the CRP level was higher in OC than that in LC (7.46 ± 0.02; 7.38 ± 0.01, P < 0.05). After operation the REE level all increased in OC and LC (P < 0.05). In the all-postoperative days, the REE level was higher in OC than that in LC (1438.5 ± 418.5; 1222.3 ± 180.8, P < 0.05).

CONCLUSION: LC results in less prominent stress response and smaller metabolic interference compared to open surgery. These advantages are beneficial to the restoration of stress hormones, the nitrogen balance, and the energy metabolism. However, LC can also induce acidemia and pulmonary hypoperfusion because of the penumoperitonium it uses during surgery.

[Hemodynamic monitoring using esophageal Doppler ultrasonography during laparoscopic cholecystectomy]

PURPOSE

To evaluate the use of a 4-mHz continuous wave esophageal Doppler monitor in the hemodynamic management of 48 ASA I to III patients undergoing laparoscopic cholecystectomy.

METHODS

General anesthesia was induced with fentanyl and propofol, maintained with N20 N20/02 and muscle relaxation was provided with atracurium. The lungs were mechanically ventilated. Non invasive arterial blood pressure, heart rate, capnography, arterial blood gas were monitored during CO2 pneumoperitoneum at 15-mmHg. Using the velocity waveform of descending aortic blood flow, the Doppler device estimated changes in cardiac output and systemic vascular resistances.

RESULTS

Peritoneal insufflation resulted in a mean 19% decrease in cardiac output (range -49 to +5%; P < 0.05) and a mean 48% increased in systemic vascular resistances (range -7 to +101%; P < 0.01). There was no relationship between changes in cardiac output and mean arterial pressure or PETCO2. The esophageal Doppler provided, in two patients, details of hypertensive peaks (mean arterial pressure > 140 mmHg) which responded to administration of nicardipine.

CONCLUSION

The Esophageal Doppler provided an easy-to-handle and non invasive tool to monitor changes in cardiac output during laparoscopic cholecystectomy. However, further comparison with a thermodilution cardiac output technique is required.