Effects of carbon dioxide pneumoperitoneum for laparoscopic cholecystectomy

The Effect of Intra-abdominal Pressure on Heart Rate Variability and Hemodynamics During Laparoscopic Cholecystectomy: A Prospective Observational Study

Introduction This study aimed to evaluate hemodynamic changes using heart rate variability (HRV) measurements in diabetic and nondiabetic patients who will undergo laparoscopic cholecystectomy and to provide our preoperative measurements to guide us for better perioperative anesthesia management. Materials and methods The study included 143 patients aged 40 years and older who would undergo elective laparoscopic surgery, did not have any comorbidities other than diabetes mellitus (DM) type II, and were in the American Society of Anesthesiologists (ASA) class I-III risk group. Patients were divided into two groups: the control group (n = 77) and the DM group (n = 66). The preoperative glycated hemoglobin (HbA1C) level was measured. Peripheral oxygen saturation (SpO2) and hemodynamic parameters such as systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), heart rate (HR), and HRV parameters were measured preoperatively, perioperatively, and postoperatively. Intra-abdominal pressure (IAP) was administered at 10-12 mmHg. Results Even though SAP, DAP, MAP, and HR decreased with induction, they increased with insufflation, and an overall decrease was seen at the postoperative 24th hour for all parameters. When the groups were evaluated, no difference was observed except that the DAP was significantly lower in the DM group (p = 0.029) at insufflation and the HR was higher in the DM group at induction, and the difference was significant (p = 0.001). Preoperative HRV parameters were significantly lower in the DM group. According to the HRV parameters, although a decrease was observed after induction and insufflation, conversely, an increase was observed postoperatively. When the postoperative and preoperative values were compared, the standard deviation of the NN (R-R) intervals (SDNN), SDNN index, high frequency (HF), low frequency (LF), and LF/HF parameters were found to be significantly lower in the DM group than in the control group. Conclusion Diabetic patients are more sensitive to increased intra-abdominal pressure (IAP) in laparoscopic surgery, and the effects on cardiac autonomic functions can be determined by HRV measurements without clinically reflecting on hemodynamic data. Additionally, in diabetic patients with preoperative LF and/or HF values less than 100, we believe that careful follow-up in terms of autonomic neuropathy complications and anesthesia management should be done more meticulously in these patients.

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.

Cardiorespiratory effects of different intraabdominal pressures in sheep: An experimental study

Increased intraabdominal pressure (IAP) during laparoscopy can reduce venous return, but changes in respiratory system mechanics and their effect in left cardiac function are not well documented. This study evaluated the effects of different IAPs on respiratory mechanics and cardiac function in 10 healthy nonpregnant adult Santa Ines ewes randomly submitted to a crossover study using different IAPs: 0 mm Hg (G1), 10 mm Hg (G2), 12 mmHg (G3), and 15 mmHg (G4). Animals were anesthetized and mechanically ventilated (VT  = 15 ml/kg; positive end-expiratory pressure = 3 cmH2 O; FiO2  = 1.0). Pneumoperitoneum was induced by Hasson's trocar cannula. Variables were measured at INITIAL (IAP, 0 mmHg) and FINAL time points for each IAP after 1 h. At FINAL, driving airway pressure (ΔP,RS ), and percentage fraction of dead space (Vd/Vt) were higher in G3 and G4 than G1 (p = 0.002, difference in means [MD] 4.60, 95% CI: 7.91-1.28, and p < 0.001, MD 5.4, 95% CI: 8.7-2.0; p = 0.016, MD -9.5, 95% CI: -17.9 to -1.2; and p = 0.027, MD -8.7, 95% CI: -17.1 to -0.4). The ejection fraction and fractional shortening were lower in G3 (p = 0.039, MD -11.38, 95% CI: -0.07--22.68; p = 0.015, MD -13.05, 95% CI: -1.74--24.36) and G4 (p = 0.039, MD -9.94, 95% CI: -0.07 to -19.80; p = 0.015, MD -11.43, 95%CI: -1.57 to -21.30, respectively) than G2. In G3, the maximum pulmonary flow velocity correlated negatively with ΔP,RS (r = -0.740; p = 0.018), and Vd/Vt correlated positively with ΔP,RS (r = 0.738, p = 0.046). At IAP of 12 and 15 mm Hg impaired respiratory system mechanics, reduced left cardiac function and no change in maximum pulmonary artery flow velocity were detected. Therefore, respiratory mechanics should be monitored as an interplay to reduce left cardiac function.

Hemodynamic derangement associated with tension pneumomediastinum during minimally invasive esophagectomy: A case report

RATIONALE

Surgery is the treatment of choice for esophageal cancer. Since the 1990s, minimally invasive esophagectomy (MIE) has been developed using videoscope. Although MIE lowers mortality by reducing postoperative complications, the risk of carbon dioxide (CO2) insufflation related complications still exists.

PATIENT CONCERNS

A 56-years-old male patient underwent elective MIE. The patient (body mass index, 15 kg/m2) had well-controlled hypertension, cardiomegaly, and severe emphysematous lungs. He had iatrogenic pneumothorax during central venous catheterization 3 weeks prior; however, the pneumothorax was resolved before surgery.

DIAGNOSIS

During thoracoscopic surgery, respiratory acidosis was not corrected despite rapid respiratory rate and positive end-expiratory pressure. Intrathoracic CO2 pressure was lowered from 12 to 8 mm Hg, and laparoscopic surgery was performed through the diaphragm in the reverse Trendelenburg position. In 15 minutes at this position, pulseless electrical activity with respiratory failure and high peak inspiratory pressure developed.

INTERVENTIONS

CO2 insufflation was stopped and drained as soon as hypotension developed. The patient was placed in the supine neutral position, and cardiopulmonary circulation was restored without further treatment.

OUTCOMES

After the pneumomediastinum event, surgery was successfully performed. Respiratory acidosis due to CO2 insufflation was not corrected during surgery and the patient was transferred to intensive care unit without extubation. After 14 days, the patient was discharged without cardiopulmonary complications. However, the patient expired 2 years later due to cardiovascular disease.

LESSONS

In MIE, there is always a risk of catastrophic tension pneumomediastinum along with intravascular volume depletion, surgical position, and ventilatory strategy depending on the surgical characteristics.

Healthy nonobese bitches maintain acceptable spontaneous ventilation during laparoscopic ovariectomies

OBJECTIVE

To determine whether end-tidal CO2 (Petco2), tidal volume (Vt), inspiratory minute volume (i), and respiratory rate (RR) remain within reference limits for spontaneously breathing dogs undergoing laparoscopic ovariectomy; characterize changes in these variables over time; and record the proportion of dogs requiring mechanical ventilation on the basis of predetermined criteria.

ANIMALS

22 client-owned dogs.

PROCEDURES

Between January and June 2019, dogs were anesthetized for abdominal insufflation (CO2; 10 mm Hg) and laparoscopic ovariectomy. Respiratory variables (Petco2, Vt, i, and RR) were recorded at 5 time points: preinsufflation (T2), immediately after insufflation (T3), immediately after first ovary extraction (T4), immediately after second ovary extraction (T5), and after abdominal deflation (T6). Results for variables were assessed to identify differences with reference limits and between time points.

RESULTS

At all time points (T2 to T6), Petco2 was within or above the reference limit, Vt was below or within reference limits, and i was either within or above reference limits. Significant temporal changes were detected in all recorded parameters. One dog had to be ventilated prior to abdominal insufflation due to inappropriately low Vt (< 6 mL/kg) and was excluded from further analysis. One of the 21 remaining dogs required rescue ventilation.

CLINICAL RELEVANCE

Following insufflation, there was a tendency toward inadequate ventilation over time characterized by increased Petco2. Twenty of 21 dogs maintained Petco2 within tolerance via a mild increase in RR and did not require assisted ventilation. Dogs undergoing short surgeries may not require assisted ventilation. Clinicians are advised to monitor for hypercapnia and be prepared to assist ventilation if required.

Fetoscopic insufflation of heated-humidified carbon dioxide during simulated spina bifida repair is safe under controlled anesthesia in the fetal lamb

OBJECTIVE

To assess the safety of Partial-Amniotic-Insufflation-of-heated-humidified-CO₂ (hPACI) during fetoscopic spina bifida repair (fSB-repair).

METHOD

A simulated fSB-repair through an exteriorized uterus under hPACI was performed in 100-day fetal lambs (term = 145 days) under a laboratory anesthesia protocol (n = 5; group 1) which is known to induce maternal-fetal acidosis and hypercapnia. Since these may not occur clinically, we applied a clinical anesthesia protocol (n = 5; group 2), keeping maternal parameters within physiological conditions, that is, controlled maternal arterial carbon dioxide (CO2) pressure (pCO₂  = 30 mmHg), blood pressure (≥67 mmHg), and temperature (37.1-39.8°C). Our superiority study used fetal pH as the primary outcome.

RESULTS

Compared to group 1, controlled anesthesia normalized fetal pH (7.23 ± 0.02 vs. 7.36 ± 0.02, p < 0.001), pCO₂ (70.0 ± 9.1 vs. 43.0 ± 1.0 mmHg, p = 0.011) and bicarbonate (27.8 ± 1.1 vs. 24.0 ± 0.9 mmol/L, p = 0.071) at baseline. It kept them within clinically acceptable limits (pH ≥ 7.23, pCO₂  ≤ 70 mmHg, bicarbonate ≤ 30 mm/L) for ≥120 min of hPACI as opposed to ≤30 min in group one. Fetal pO₂ and lactate were comparable between groups and generally within normal range. Fetal brain histology demonstrated fewer apoptotic cells and higher neuronal density in the prefrontal cortex in group two. There was no difference in fetal membrane inflammation, which was mild.

CONCLUSION

Fetoscopic insufflation of heated-humidified CO₂ during simulated fSB-repair through an exteriorized uterus can be done safely under controlled anesthesia.

Gastric and urinary bladder pressures correlate with intra-abdominal pressure in patients with morbid obesity

Intra-abdominal pressure (IAP) affects cardio-respiratory and hemodynamic parameters and can be measured directly or indirectly by measuring gastric or urinary bladder pressure. The aim of this study was to investigate the correlation between IAP, gastric pressure and urinary bladder pressure in patients with morbid obesity, at normal and elevated levels of IAP in two positions. As well, to examine the effects of increasing IAP and patient's position on hemodynamic and respiratory parameters. Twelve patients undergoing laparoscopic bariatric surgery were included. IAP, gastric pressure, and urinary bladder pressure were measured while patients were in the supine position and after 45° anti-Trendelenburg tilt. Mean inspiratory pressure, peak inspiratory pressure, and tidal volume were recorded and assessed. In supine position; directly measured IAP was 9.1 ± 1.8 mmHg, compared to 10 ± 3.6 and 8.9 ± 2.9 mmHg in the stomach and bladder, respectively. Increasing IAP to 15 mmHg resulted in an increased gastric pressure of 17 ± 3.8 mmHg, and urinary bladder pressure of 14.8 ± 3.9 mmHg. Gastric and urinary bladder pressures strongly correlated with IAP (R = 0.875 and 0.847, respectively). With 45° anti-Trendelenburg tilt; directly measured IAP was 9.4 ± 2.2 mmHg, and pressures of 10.8 ± 3.8 mmHg and 9.2 ± 3.8 mmHg were measured in the stomach and the bladder, respectively. Increasing IAP to 15 mmHg resulted in elevating gastric and bladder pressures to 16.6 ± 5.3 and 13.3 ± 4 mmHg, respectively. Gastric and urinary bladder pressures had good correlation with IAP (R = 0.843 and 0.819, respectively). Changing patient position from supine to 45° anti-Trendelenburg position resulted in decreased mean and peak inspiratory pressures, and increased tidal volume. Basal IAP is high in patients with morbid obesity. IAP shows positive correlation to gastric and urinary bladder pressures at both normal and elevated levels of IAP. Anti-Trendelenburg tilt of mechanically ventilated morbidly obese patients resulted in favorable effects on respiratory parameters.

Trial Registration: The study was retrospectively registered in the NIH registry. Registration number is pending.

Predictive value of the respiratory exchange ratio for the occurrence of postoperative complications in laparoscopic surgery: a prospective and observational study

Indirect measurement of the respiratory exchange ratio (RER) has been shown to predict the occurrence of postoperative complications after major open non-cardiac surgery. Our main objective was to demonstrate the ability of the RER, indirectly measured by the anaesthesia respirator, to predict the occurrence of postoperative complications following laparoscopic surgery. We performed an observational, prospective and monocentric study. Haemodynamic and respiratory parameters were collected at several timepoints to calculate the RER by a non-volumetric method: RER = (FetCO₂-FiCO₂)/(FiO₂-FetO₂). Fifty patients were prospectively included. Nine patients (18%) had at least one postoperative complication. The mean RER was significantly higher for the subgroup of patients with complications than the subgroup without (1.04 ± 0.27 vs 0.88 ± 0.13, p < 0.05). The RER could predict the occurrence of post-operative complications with an area under the ROC curve of 0.73 (95% CI 0.59-0.85, p = 0.021). The best cut off was 0.98, with a sensitivity of 56% and a specificity of 88%. One hour after insufflation, the FiO₂-FetO₂ difference was significantly lower and the RER was significantly higher in the complications subgroup than in the subgroup without complications (4.4/- 1.6% vs 5.8/- 1.2%, p = 0.001 and 0.95 [0.85-1.04] vs 0.83 [0.75-0.92], p = 0.04, respectively). The RER measured during laparoscopic surgery can predict the occurrence of postoperative complications.Trial registration The objectives and procedures of the study was registered at Clinicaltrials.gov (NCT03751579); date: November 23, 2018.

Comparison of volume-controlled, pressure-controlled, and pressure-controlled volume-guaranteed ventilation during robot-assisted laparoscopic gynecologic surgery in the Trendelenburg position

Background: Pressure-controlled ventilation volume-guaranteed (PCV-VG) is being increasingly used for ventilation during general anesthesia. Carbon dioxide (CO₂) pneumoperitoneum in the Trendelenburg position is routinely used during robot-assisted laparoscopic gynecologic surgery. Here, we hypothesized that PCV-VG would reduce peak inspiratory pressure (Ppeak), compared to volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV). Methods: In total, 60 patients were enrolled in this study and randomly assigned to receive VCV, PCV, or PCV-VG. Hemodynamic variables, respiratory variables, and arterial blood gases were measured in the supine position 15 minutes after the induction of anesthesia (T0), 30 and 60 minutes after CO₂ pneumoperitoneum and Trendelenburg positioning (T1 and T2, respectively), and 15 minutes after placement in the supine position at the end of anesthesia (T3). Results: The Ppeak was higher in the VCV group than in the PCV and PCV-VG groups (p=0.011). Mean inspiratory pressure (Pmean) was higher in the PCV and PCV-VG groups than in the VCV group (p<0.001). Dynamic lung compliance (Cdyn) was lower in the VCV group than in the PCV and PCV-VG groups (p=0.001). Conclusion: Compared to VCV, PCV and PCV-VG provided lower Ppeak, higher Pmean, and improved Cdyn, without significant differences in hemodynamic variables or arterial blood gas results during robot-assisted laparoscopic gynecologic surgery with Trendelenburg position.

Effects of different doses of magnesium sulfate on pneumoperitoneum-related hemodynamic changes in patients undergoing gastrointestinal laparoscopy: a randomized, double-blind, controlled trial

BACKGROUND

The infusion of magnesium sulfate is well known to reduce arterial pressure and attenuate hemodynamic response to pneumoperitoneum. This study aimed to investigate whether different doses of magnesium sulfate can effectively attenuate the pneumoperitoneum-related hemodynamic changes and the release of vasopressin in patients undergoing laparoscopic gastrointestinal surgery.

METHODS

Sixty-nine patients undergoing laparoscopic partial gastrectomy were randomized into three groups: group L received magnesium sulfate 30 mg/kg loading dose and 15 mg/kg/h continuous maintenance infusion for 1 h; group H received magnesium sulfate 50 mg/kg followed by 30 mg/kg/h for 1 h; and group S (control group) received same volume 0.9% saline infusion, immediately before the induction of pneumoperitoneum. Systemic vascular resistance (SVR), cardiac output (CO), mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), serum vasopressin and magnesium concentrations were measured. The extubation time, visual analogue scale were also assessed. The primary outcome is the difference in SVR between different groups. The secondary outcome is the differences of other indicators between groups, such as CO, MAP, HR, CVP, vasopressin and postoperative pain score.

RESULTS

Pneumoperitoneum instantly resulted in a significant reduction of cardiac output and an increase in mean arterial pressure, systemic vascular resistance, central venous pressure and heart rate in the control group (P <  0.01). The mean arterial pressure (T2 - T4)_, systemic vascular resistance (T2 - T3), central venous pressure(T3-T5) and the level of serum vasopressin were significantly lower (P <  0.05) and the cardiac output (T2 - T3) was significantly higher (P <  0.05) in group H than those in the control group. The mean arterial pressure (T4), systemic vascular resistance (T2), and central venous pressure(T3-T4) were significantly lower in group H than those in group L (P <  0.05). Furthermore, the visual analog scales at 5 min and 20 min, the level of vasopressin, and the dose of remifentanil were significantly decreased in group H compared to the control group and group L (P <  0.01).

CONCLUSION

Magnesium sulfate could safely and effectively attenuate the pneumoperitoneum-related hemodynamic instability during gastrointestinal laparoscopy and improve postoperative pain at serum magnesium concentrations above 2 mmol/L.

TRIAL REGISTRATION

The study was retrospectively registered at Chinese Clinical Trial Registry; the registration number is ChiCTR-IPD-17011145, principal investigator: D.Y. Q., date of registration: April 13, 2017.

Pulse Pressure Variation Can Predict the Hemodynamic Response to Pneumoperitoneum in Dogs: A Retrospective Study

Pneumoperitoneum may induce important hemodynamic alterations in healthy subjects. Pulse pressure variation (PPV) is a hemodynamic parameter able to discriminate preload dependent subjects. Anesthesia records of dogs undergoing laparoscopy were retrospectively evaluated. The anesthetic protocol included acepromazine, methadone, propofol and isoflurane administered with oxygen under mechanical ventilation. The hemodynamic parameters were considered five minutes before (BASE) and ten minutes after (P10) the pneumoperitoneum. Based on the cardiac index (CI) variation, at P10, dogs were classified as sensitive (S group, CI ≤ 15%) and non-sensitive (NO-S group). Data were analyzed with the ANOVA test and the ROC curve (p < 0.05). Fifty-five percent of dogs (S) had a reduction of CI ≥ 15% at P10 (2.97 ± 1.4 L/min/m²) compared to BASE (4.32 ± 1.62 L/min/m²) and at P10 in the NO-S group (4.51 ± 1.41 L/min/m²). PPV at BASE was significantly higher in the S group (22.4% ± 6.1%) compared to the NO-S group (10.9% ± 3.3%). The ROC curve showed a threshold of PPV > 16% to distinguish the S and NO-S groups. PPV may be a valid predictor of the hemodynamic response to pneumoperitoneum in dogs. A PPV > 16% can identify patients that may require fluid administration before the creation of pneumoperitoneum.

Changes in Hepatic Blood Flow and Liver Function during Closed Abdominal Hyperthermic Intraperitoneal Chemotherapy following Cytoreduction Surgery

BACKGROUND

The increase in intra-abdominal pressure (IAP) during closed abdominal hyperthermic intraperitoneal chemotherapy (HIPEC) leads to major haemodynamic changes and potential organ dysfunction. We investigated these effects on hepatic blood flow (HBF) and liver function in patients undergoing HIPEC following cytoreductive surgery and fluid management guided by dynamic preload indices.

METHODS

In this prospective observational clinical study including 15 consecutive patients, we evaluated HBF by transesophageal echocardiography and liver function by determination of the indocyanine green plasma disappearance rate (ICG-PDR). Friedman's two-way analysis of variance by ranks and Wilcoxon signed-rank test were performed for statistical analysis.

RESULTS

During HIPEC, HBF was markedly reduced, resulting in the loss of any pulsatile Doppler flow signal in all but one patient. The ICG-PDR, expressed as median (interquartile 25-75), decreased from 23 (20-30) %/min to 18 (12.5-19) %/min (p < 0.001). Despite a generous crystalloid infusion rate (27 (22-35) ml/kg/h), cardiac index decreased during the increased IAP period, inferior vena cava diameter decreased, stroke volume variation and pulse pressure variation increased, lung compliance dropped, and there was an augmentation in plateau pressure. All changes were significant (p < 0.001) and reversed to baseline values post HIPEC.

CONCLUSION

Despite optimizing intravenous fluids during closed abdominal HIPEC, we observed a marked decrease in HBF and liver function. Both effects were transient and limited to the period of HIPEC but could influence the choice between closed or open abdominal cavity procedure for HIPEC and should be considered in similar clinical situations of increased IAP.

Comparative Study of the Effect of Dexmedetomidine Vs. Fentanyl on Haemodynamic Response in Patients Undergoing Elective Laparoscopic Surgery

Introduction

Dexmedetomidine and fentanyl, both have sedative and analgesic effects. They are often used as adjunct during anaesthesia to attenuate pressor response during tracheal intubation. Limited study has been done comparing the effect of both drugs on haemodynamic response in patients undergoing laparoscopic surgery.

Aim

The study was designed to compare the effect of dexmedetomidine Vs fentanyl on haemodynamic response to tracheal intubation, following pneumoperitoneum and intraoperative period in patients undergoing laparoscopic surgery.

Materials and Methods

Sixty patients of age group 18-60 years of either sex, classified as American Society of Anaesthesiologist (ASA) Grade I and II undergoing elective laparoscopy surgery were randomly allocated to one of the two groups (Group-D) and (Group F) of 30 each. Group D received dexmedetomidine and Group F received fentanyl. Patients received intravenous 0.5 μg/kg of the study drug as loading dose over 10 minutes prior to intubation followed by 0.2-0.7 μg/kg/hr as infusion till surgery was over. In operating room parameters like Heart Rate (HR), Respiratory Rate (RR), Systolic Blood Pressure (SBP), Mean Arterial Pressure (MAP), SpO₂, EtCO₂ were recorded 10 minutes after infusion of drug i.e., dexmedetomidine or fentanyl. The said parameters were again recorded after injection of induction drugs, after intubation, five minutes after intubation, just after pneumoperitoneum, and 5,10,15,30,45 and 60 minutes after pneumoperitoneum, five minutes after release of pneumoperitoneum, five and 10 minutes after extubation.

Results

Dexmedetomidine significantly attenuates stress response at intubation with lesser increase in HR (5% Vs 18%), SBP (9% Vs 19%) and DBP (3% Vs 15%), MAP (2% Vs 15%) as compared to fentanyl (p<0.05). Throughout intraoperative period of pneumoperitoneum Group D showed significant fall in HR, SBP, DBP, MAP from baseline value at all points of time intervals whereas it remained constantly high above baseline value in Group F (p-value <0.05).

Conclusion

Dexmedetomidine when compared to fentanyl causes greater attenuation of stress response to tracheal intubation, following pneumoperitoneum and in intraoperative period resulting in greater reduction of HR, SBP, DBP, MAP than that of fentanyl, thus causing better haemodynamic stability in patients undergoing elective laparoscopic surgery.

Effects of Low-Flow Sevoflurane Anesthesia on Pulmonary Functions in Patients Undergoing Laparoscopic Abdominal Surgery

Objective. The aim of this prospective, randomized study was to investigate the effects of low-flow sevoflurane anesthesia on the pulmonary functions in patients undergoing laparoscopic cholecystectomy. Methods. Sixty American Society of Anesthesiologists (ASA) physical status classes I and II patients scheduled for elective laparoscopic cholecystectomy were included in the study. Patients were randomly allocated to two study groups: high-flow sevoflurane anesthesia group (Group H, n = 30) and low-flow sevoflurane anesthesia group (Group L, n = 30). The fresh gas flow rate was of 4 L/min in high-flow sevoflurane anesthesia group and 1 L/min in low-flow sevoflurane anesthesia group. Heart rate (HR), mean arterial blood pressure (MABP), peripheral oxygen saturation (SpO₂), and end-tidal carbon dioxide concentration (ETCO₂) were recorded. Pulmonary function tests were performed before and 2, 8, and 24 hours after surgery. Results. There was no significant difference between the two groups in terms of HR, MABP, SpO₂, and ETCO₂. Pulmonary function test results were similar in both groups at all measurement times. Conclusions. The effects of low-flow sevoflurane anesthesia on pulmonary functions are comparable to high-flow sevoflurane anesthesia in patients undergoing laparoscopic cholecystectomy.

The impact of intra-abdominal pressure on the stroke volume variation and plethysmographic variability index in patients undergoing laparoscopic cholecystectomy

The purpose of the present study was to evaluate the effect of increasing intra-abdominal pressure (IAP) on stroke volume variation (SVV) and plethysmographic variability index (PVI) in patients undergoing laparoscopic cholecystectomy. PVI examined by Masimo Radical 7 pulse oximeter and SVV determined using FloTrac/Vigileo were monitored simultaneously in forty-five patients undergoing laparoscopic cholecystectomy (LC). Mean arterial blood pressure (MAP), heart rate (HR), cardiac index (CI), perfusion index (PI), airway pressures (P), SVV, and PVI were also recorded at the following predetermined time: 5 min after endotracheal intubation (T1), 5 min after pneumoperitoneum at 5 mmHg (T2), 5 min after pneumoperitoneum at 10 mmHg (T3), 5 min after pneumoperitoneum at 15 mmHg (T4), and 5 min after the termination of pneumoperitoneum (T5). Forty-five patients with a total of 225 pairs of measurements were included in the analysis. Compared with the values at T1, both SVV and PVI showed significant progressive increases as the IAP was adjusted from 5 to 10, 15 mmHg at T2, T3, and T4, respectively. No significant difference was found when the pneumoperitoneum was terminated at T5. Further regressive analysis indicated strong relationships between SVV and IAP (r = 0.8118, p < 0.001), PVI and IAP(r = 0.8876, p < 0.001) respectively. Both PVI and SVV showed rapid and IAP correlative changes with increasing intra-abdominal pressure in patients undergoing laparoscopic cholecystectomy.

The Effects of Volume-Controlled and Pressure-Controlled Ventilation on Lung Mechanics, Oxidative Stress, and Recovery in Gynecologic Laparoscopic Surgery

STUDY OBJECTIVE

To compare ventilation variables, changes in oxidative stress, and the quality of recovery in 2 different ventilation strategies (volume-controlled ventilation [VCV] and pressure-controlled ventilation [PCV]) during gynecologic laparoscopic surgery.

DESIGN

A prospective randomized controlled trial (Canadian Task Force classification I).

SETTING

One university teaching hospital in Taiwan.

PATIENTS

Women scheduled for laparoscopic gynecologic surgery.

INTERVENTIONS

Women were randomly assigned to receive either VCV or PCV during surgery.

MEASUREMENTS AND MAIN RESULTS

Ventilation variables were recorded 1 minute before and 1 hour after pneumoperitoneum. Blood samples were collected for malondialdehyde measurement at 7 points: 1 minute before and 1 hour after pneumoperitoneum; 30, 60, 90, and 120 minutes after deflation; and 24 hours after surgery. Postoperative recovery was assessed by using a 9-item quality of recovery score at 24 hours after surgery. A total of 52 women randomly allocated to the VCV (n = 27) or PCV (n = 25) group completed the study. We found that after 1 hour of insufflation the PCV group had lower peak airway pressure (22.0 ± 3.4 vs 26.6 ± 4.1 cm H2O, p < .0001) and higher compliance (28.4 ± 3.7 vs 24.1 ± 3.3 mL/cm H2O, p < .0001) than the VCV group. In plasma levels of malondialdehyde, there were no significant differences between the 2 groups at 7 time points. The levels significantly increased in both groups after 1 hour of pneumoperitoneum and peaked at 2 hours after deflation. During postoperative recovery, lower scores were obtained at 24 hours after surgery compared with preoperative scores, but there were no significant differences between the 2 groups.

CONCLUSION

PCV is an alternative ventilation mode in gynecologic laparoscopic surgery. However, PCV offered lower peak airway pressure and higher compliance than VCV but no advantages over VCV in oxidative stress or quality of recovery.

Effect of supplemental oxygen 80 % on post-tonsillectomy nausea and vomiting: a randomized controlled trial

Nausea and vomiting are two of the most common complications of tonsillectomy in children. Administration of supplemental 80 % oxygen during surgery reduces the incidence of postoperative nausea and vomiting. We aimed to test the efficacy of supplemental 80 % oxygen during tonsillectomy on postoperative nausea and vomiting. In a randomized controlled trial in Shahid Mostafa Khomeini Hospital in Tehran, 102 children scheduled for tonsillectomy (± adenoidectomy) under general anesthesia were divided randomly in two groups according to percent of administered oxygen (group 1:30 % oxygen, group 2:80 % oxygen). The incidence of postoperative nausea and vomiting were assessed and compared in 0-2, 2-6 and 6-24 h after surgery. Incidence of post-tonsillectomy nausea and vomiting after 2, 2-6, and 6-24 h was 13.72, 1.96 and 1.96 % for group 1 and 3.92, 0 and 1.96 % in group 2, respectively. We found no statistically significant difference between two groups (P = 0.08) but 80 % oxygen was beneficial for reducing postoperative nausea and vomiting in the first 2 h after surgery in group 2.

Cerebral oxygenation measured by near-infrared spectroscopy and jugular vein oxygen saturation during robotic-assisted laparoscopic radical prostatectomy under total intravenous anaesthesia

BACKGROUND

The effects of total intravenous anaesthesia (TIVA) on cerebral oxygenation in patients undergoing robot-assisted laparoscopic radical prostatectomy (RALP) have not been investigated. We examined the changes in jugular venous oxygen saturation (SjvO₂ ) and regional cerebral tissue oxygen saturation (rSO₂ ) during RALP under TIVA. Whether rSO₂ could reflect SjvO₂ was also examined.

METHODS

Forty patients (ASA 1-2) undergoing RALP were enrolled. Measurements were obtained at eight time points during the operation.

RESULTS

SjvO₂ did not decrease at any measurement point, whereas rSO₂ fell significantly 120 min after pneumoperitoneum in a steep Trendelenburg position (p <0.01). There was a weak correlation between SjvO₂ and rSO₂ (Pearson correlation coefficient =0.34; p <0.01). Bland-Altman analysis showed a wide interval for the limit of agreement (47%) between the two measurements.

CONCLUSIONS

These findings suggested that TIVA could be safely used for RALP. It was also demonstrated that rSO₂ did not accurately reflect SjvO₂ during RALP. Copyright © 2014 John Wiley & Sons, Ltd.

Effect of pneumoperitoneum on the recovery from intense neuromuscular blockade by rocuronium in healthy patients undergoing laparoscopic surgery

BACKGROUND

This study investigated the effect of pneumoperitoneum on the recovery from intense neuromuscular blockade by rocuronium in healthy patients undergoing laparoscopic abdominal surgery.

METHODS

Thirty adult patients undergoing laparoscopic abdominal surgery were studied. Anesthesia was induced with 1.5 mg/kg of propofol, 12 ug/kg of alfentanil and 0.6 mg/kg of rocuronium and maintained with 2 vol% of sevoflurane and 0.05-0.2 µg/kg/min remifentanil. The neuromuscular relaxation was monitored by Train-of-Four (TOF) and post-tetanic count (PTC). Additional rocuronium of 0.2 mg/kg was administered for deep neuromuscular blockade at 30 min after pneumoperitoneum. Before (PPpre) and 30 min after pneumoperitoneum (PPpost), PTC was measured at 6 min intervals. The relationship between PTC and the time interval to reappearance of T1 response was observed.

RESULTS

The mean ± SD of the intervals between the detection of 4 counts of the PTC and the first response to TOF stimulation was 13.0 ± 1.1 min and 16.4 ± 6.3 min PPpre and PPpost, respectively (P = 0.20). There were significant negative relationships between PTC observed and the time interval to reappearance of T1 response (adjusted R(2) = 0.869, P < 0.001 for PPpre data, and adjusted R(2) = 0.561, P < 0.001 for PPpost data). Comparing the difference of regression equation between PPpre and PPpost data using a parallelism test, there was no statistically significant difference (P = 0.193).

CONCLUSIONS

This study showed that PP with intra-abdominal pressure at the level of 13-14 mmHg did not affect the recovery from intense neuromuscular blockade by rocuronium in healthy patients undergoing laparoscopic abdominal surgery.

Effects of elevated artificial pneumoperitoneum pressure on invasive blood pressure and levels of blood gases

BACKGROUND AND OBJECTIVE

to evaluate the clinical, hemodynamic, gas analysis and metabolic repercussions of high transient pressures of pneumoperitoneum for a short period of time to ensure greater security for introduction of the first trocar.

METHODS

sixty-seven patients undergoing laparoscopic procedures were studied and randomly distributed in P12 group: n=30 (intraperitoneal pressure [IPP] 12mmHg) and P20 group: n=37 (IPP of 20mmHg). Mean arterial pressure (MAP) was evaluated by catheterization of the radial artery; and through gas analysis, pH, partial pressure of oxygen (PaO2), partial pressure of CO2 (PaCO2), bicarbonate (HCO3) and alkalinity (BE) were evaluated. These parameters were measured in both groups at time zero before pneumoperitoneum (TP0); at time 1 (TP1) when IPP reaches 12mmHg in both groups; at time 2 (TP2) after five min with IPP=12mmHg in P12 and after 5min with IPP=20mmHg at P20; and at time 3 (TP3) after 10min with IPP=12mmHg in P12 and with return of IPP from 20 to 12mmHg, starting 10min after TP1 in P20. Different values from those considered normal for all parameters assessed, or the appearance of atypical organic phenomena, were considered as clinical changes.

RESULTS

there were statistically significant differences in P20 group in MAP, pH, HCO3 and BE, but within normal limits. No clinical and pathological changes were observed.

CONCLUSIONS

high and transient intra-abdominal pressure causes changes in MAP, pH, HCO3 and BE, but without any clinical impact on the patient.

Effects of elevated artificial pneumoperitoneum pressure on invasive blood pressure and levels of blood gases

BACKGROUND AND OBJECTIVE

to evaluate the clinical, hemodynamic, gas analysis and metabolic repercussions of high transient pressures of pneumoperitoneum for a short period of time to ensure greater security for introduction of the first trocar.

METHODS

sixty-seven patients undergoing laparoscopic procedures were studied and randomly distributed in P12 group: n=30 (intraperitoneal pressure [IPP] 12mmHg) and P20 group: n=37 (IPP of 20mmHg). Mean arterial pressure (MAP) was evaluated by catheterization of the radial artery; and through gas analysis, pH, partial pressure of oxygen (PaO2), partial pressure of CO2 (PaCO2), bicarbonate (HCO3) and alkalinity (BE) were evaluated. These parameters were measured in both groups at time zero before pneumoperitoneum (TP0); at time 1 (TP1) when IPP reaches 12mmHg in both groups; at time 2 (TP2) after five min with IPP=12mmHg in P12 and after 5min with IPP=20mmHg at P20; and at time 3 (TP3) after 10min with IPP=12mmHg in P12 and with return of IPP from 20 to 12mmHg, starting 10min after TP1 in P20. Different values from those considered normal for all parameters assessed, or the appearance of atypical organic phenomena, were considered as clinical changes.

RESULTS

there were statistically significant differences in P20 group in MAP, pH, HCO3 and BE, but within normal limits. No clinical and pathological changes were observed.

CONCLUSIONS

high and transient intra-abdominal pressure causes changes in MAP, pH, HCO3 and BE, but without any clinical impact on the patient.

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.

Is muscle relaxant necessary in patients undergoing laparoscopic gynecological surgery with a ProSeal LMA™?

STUDY OBJECTIVE

To test the hypothesis that muscle relaxant is not necessary in patients who are undergoing laparoscopic gynecological surgery with a ProSeal Laryngeal Mask Airway (ProSeal LMA™).

DESIGN

Prospective, randomized study.

SETTING

Operating room of Sichuan Provincial Hospital for Women and Children.

PATIENTS

120 adult, ASA physical status 1 and 2 women, aged 18 to 55 years.

INTERVENTIONS AND MEASUREMENTS

Patients were randomly assigned to two groups (n=60) to receive a muscle relaxant (Group MR) or not (Group NMR). General anesthesia was used in patients of both groups for airway management with the ProSeal LMA. Peak airway inflation pressures, airway sealing pressure, minimum flow rate, and recovery time were assessed. Surgical conditions were assessed by the operating gynecologist. The frequency of sore throats was recorded.

MAIN RESULTS

ProSeal LMA insertion was 100% successful. Patients' lungs were ventilated with a maximum sealing pressure of 32 ± 5.1 cm H(2)O (Group MR) or 31 ± 4.9 cm H(2)O (Group NMR) (P = 0.341). The seal quality in both groups permitted the use of low flows: 485 ± 291 mL/min in Group MR and 539 ± 344 mL/min in Group NMR (P = 0.2). Surgical conditions were comparable between the two groups. There was no difference in the frequency of sore throats (20% vs 21.7%; P = 0.28). In Group NMR, there was a statistically significant reduction in recovery time versus Group MR (4.5 ± 2.6 min vs 10.3 ± 4.2 min; P < 0.01).

CONCLUSION

Muscle relaxant is not necessary in general anesthesia with a ProSeal LMA.

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.

Carbon dioxide embolism during laparoscopic surgery

Clinically significant carbon dioxide embolism is a rare but potentially fatal complication of anesthesia administered during laparoscopic surgery. Its most common cause is inadvertent injection of carbon dioxide into a large vein, artery or solid organ. This error usually occurs during or shortly after insufflation of carbon dioxide into the body cavity, but may result from direct intravascular insufflation of carbon dioxide during surgery. Clinical presentation of carbon dioxide embolism ranges from asymptomatic to neurologic injury, cardiovascular collapse or even death, which is dependent on the rate and volume of carbon dioxide entrapment and the patient's condition. We reviewed extensive literature regarding carbon dioxide embolism in detail and set out to describe the complication from background to treatment. We hope that the present work will improve our understanding of carbon dioxide embolism during laparoscopic surgery.

The effect of nitroglycerin on hemodynamic changes during laparoscopic low anterior resection

BACKGROUND

More laparoscopic low anterior resections (LAR) are being performed in recent years. There has been controversy around the hemodynamic changes affected by the Trendelenburg position and pneumoperitoneum during LAR. The goal of this study was to analyze the effect of nitroglycerin (NTG) on hemodynamic changes during LAR.

METHODS

Forty ASA physical status I-II patients undergoing LAR were randomized into two groups: the NTG infused group (N group, n = 20) and the control group (C group, n = 20). Anesthesia was maintained with sevoflurane at 1-3 vol%, air/oxygen (50%/50%) and continuous infusion with remifentanil. The N group patients were given 0.5 µg/kg/min of NTG during anesthesia. Mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), cardiac index (CI), stroke volume (SV) and systemic vascular resistance (SVR) were assessed 10 min after induction (T1), 5 min after pneumoperitoneum in the supine position (T2), 10 min after pneumoperitoneum in the Trendelenburg position (T3), 30 min after pneumoperitoneum in the Trendelenburg position (T4), 1 hr after pneumoperitoneum in the Trendelenburg position (T5) in addition to 5 (T6), 10 (T7) and 30 min (T8) after removal of the pneumoperitoneum in the supine position.

RESULTS

The increases of MAP were milder in the N group (22.6-7.3%) than the C group (32.3-17.7%) during pneumoperitoneum and while in the Trendelenburg position. The significant decreases of HR were maintained in the C group, but the changes in HR were not significant in N group during the operation. The increases in CVP were less in N group than C group. The increases of SVR were milder in N group (19.4-1.4%) than C group (41.7-16.6%) during pneumoperitoneum in the Trendelenburg position.

CONCLUSIONS

Intraoperative NTG infusions were effective to some degree in reducing the hemodynamic changes during pneumoperitoneum with Trendelenburg positioning for LAR.

Feasibility and safety of EUS-guided transgastric/transduodenal gallbladder drainage with single-step placement of a modified covered self-expandable metal stent in patients unsuitable for cholecystectomy

BACKGROUND

Although early laparoscopic cholecystectomy is the treatment of choice for patients with acute cholecystitis, percutaneous cholecystostomy has been performed in patients unsuitable for cholecystectomy. EUS-guided transgastric/transduodenal gallbladder drainage by using a plastic stent and/or nasobiliary drainage may be an alternative effective treatment for these patients, but bile leakage into the peritoneal space causing bile peritonitis is not uncommon during placement of a plastic stent.

OBJECTIVE

To evaluate the technical feasibility and safety of EUS-guided transgastric/transduodenal gallbladder drainage with single-step placement of a modified covered self-expandable metal stent (CSEMS) in patients with acute cholecystitis who are unsuitable for cholecystectomy.

DESIGN

Prospective feasibility study.

SETTING

Tertiary-care referral center.

PATIENTS

This study involved 15 patients with acute cholecystitis who did not respond to initial medical treatment and were unsuitable for cholecystectomy.

INTERVENTION

EUS-guided transgastric/transduodenal gallbladder drainage with single-step placement of a modified CSEMS.

MAIN OUTCOME MEASUREMENTS

Technical success, functional success, complications associated with the placement of a metal stent, and recurrence of acute cholecystitis.

RESULTS

Modified CSEMSs were successfully placed in all patients through the stomach (n = 10) or duodenum (n = 5). All patients achieved functional success within 3 days of metal stent placement. Pneumoperitoneum occurred in two patients during or after the procedure, but both patients improved with conservative management. During follow-up (median 145 days, range 60-297 days), no patient experienced recurrent cholecystitis.

LIMITATIONS

Small patient population without long-term follow-up.

CONCLUSION

Placement of a modified CSEMS after EUS-guided transgastric/transduodenal gallbladder drainage may be a feasible and safe alternative to treatments such as percutaneous cholecystostomy in patients with acute cholecystitis who are unsuitable for cholecystectomy.

Comparison of volume-controlled and pressure-controlled ventilation using a laryngeal mask airway during gynecological laparoscopy

Background

Several publications have reported the successful, safe use of Laryngeal Mask Airway (LMA)-Classic devices in patients undergoing laparoscopic surgery. However, there have been no studies that have examined the application of volume-controlled ventilation (VCV) or pressure-controlled ventilation (PCV) using a LMA during gynecological laparoscopy. The aim of this study is to compare how the VCV and PCV modes and using a LMA affect the pulmonary mechanics, the gas exchange and the cardiovascular responses in patients who are undergoing gynecological laparoscopy.

Methods

Sixty female patients were randomly allocated to one of two groups, (the VCV or PCV groups). In the VCV group, baseline ventilation of the lung was performed with volume-controlled ventilation and a tidal volume of 10 ml/kg ideal body weight (IBW). In the PCV group, baseline ventilation of the lung using pressure-controlled ventilation was initiated with a peak airway pressure that provided a tidal volume of 10 ml/kg IBW and an upper limit of 35 cmH₂O. The end-tidal CO₂, the peak airway pressures (P_peak), the compliance, the airway resistance and the arterial oxygen saturation were recorded at T1: 5 minutes after insertion of the laryngeal airway, and at T2 and T3: 5 and 15 minutes, respectively, after CO₂ insufflation.

Results

The P_peak at 5 minutes and 15 minutes after CO₂ insufflation were significantly increased compared to the baseline values in both groups. Also, at 5 minutes and 15 minutes after CO₂ insufflation, there were significant differences of the P_peak between the two groups. The compliance decreased in both groups after creating the pneumopertoneim (P < 0.05).

Conclusions

Our results demonstrate that PCV may be an effective method of ventilation during gynecological laparoscopy, and it ensures oxygenation while minimizing the increases of the peak airway pressure after CO₂ insufflation.

Effects of the tourniquet deflation on bispectral index during knee arthroscopic surgery under the general anesthesia

BACKGROUND

Tourniquet deflation during lower extremity surgery affects the hemodynamics and metabolism of the patient, which can affect brain activity. This study examined the changes in brain activity during tourniquet deflation by measuring the bispectral index (BIS).

METHODS

The BIS was measured during surgery in forty patients who had received knee arthroscopic surgery under general anaesthesia. The BIS was measured 5 minutes before deflation (DB5) and 5 minutes after deflation (DA5).

RESULTS

The BIS at DB5 and DA5 was 50.2 +/- 9.9 and 44.4 +/- 10.4, respectively. The BIS of DA5 was significantly lower than that of DB5 (P < 0.05).

CONCLUSIONS

Tourniquet deflation during lower extremity surgery decreases the BIS associated with hemodynamic and metabolic changes. However, its clinical significance in neurologically critical patients, such as geriatric or neurologically disabled patients, remains to be clarified.

Cholecystectomy in sickle cell disease patients: is there more acute chest syndrome after laparoscopy? A case controlled study

Laparoscopy is increasingly being recommended in order to reduce postoperative complications among sickle cell disease patients undergoing cholecystectomy. Acute chest syndrome is the most deadly of these complications. The purpose of this study was to assess if laparoscopic approach reduces postoperative complications related to sickle cell disease after cholecystectomy. A retrospective study of records of sickle cell patients who underwent cholecystectomy for cholelithiasis, from January 1990 to December 2005 was conducted. 136 sickle cell patients underwent surgery: 47 (34.5%) by laparoscopy and 89 (63.5%) by laparotomy. The mean operative time was 71.4+/-18.9 min in the laparoscopy group and 61.2+/-15.3 min in the laparotomy group (non-significant difference). The mortality was not significantly different between the two groups: one patient died in the open cholecystectomy group but no death occurred in the laparoscopic one. The morbidity related to the sickle cell disease was significantly higher in the laparoscopy group [n=5 (10.5%)] than in the laparotomy group [n=4 (4.5%)] (p=0.04). This difference was associated with a higher rate of acute chest syndrome in the laparoscopy group [n=4 (8, 5%)] compared to that in the laparotomy group [n=1 (1.1%)] (p=0.01). There were more complications related to sickle cell disease in the laparoscopy group due to acute chest syndrome. Thus, these data should be confirmed in further randomized studies which must be undertaken.

Comparative Analysis of the Hemodynamic and Respiratory Parameters During Laparoscopic Versus Open Living Donor Nephrectomy: An Experimental Model

Increased intrabdominal pressure induced by pneumoperitoneum induces modifications in cardiovascular and respiratory systems. The aim of the study was to analyze the hemodynamic and respiratory modifications produced by pneumoperitoneum during living donor nephrectomy in a porcine experimental model. Twenty pigs underwent left nephrectomy, 10 by laparoscopy and 10 by an open approach. The following parameters were measured: mean arterial pressure (MAP), central venous pressure, cardiac output (CO), systemic vascular resistance (SVR), end tidal CO2 (ETCO2), minute volume (MV), respiratory airway pressure (RAP), and "compliance." Both groups were monitored for cardiac and respiratory systems at basal, 5, 30, and 60 minutes as well as postsurgery. The comparative analysis demonstrated increased CO with a higher difference at 30 minutes (4.33 +/- 0.73 vs 8.54 +/- 1.26 L/min, P < .001); decreased SVR (1118.81 +/- 302.52 vs 663.37 +/- 81.45 dinas x s x cm(-5), P < .001), and elevated MAP among the laparoscopic group (66.5 +/- 11.52 vs 80.25 +/- 2.49 mm Hg, P = .004). Analysis of respiratory modifications showed an initial increase in ETCO2 (44.3 +/- 2.6 vs 54.1 +/- 12.56 mm Hg, P < .035) and a higher MV administered (5.6 +/- 0.1 vs 7.01 +/- 0.96 L/min, P = .03) to the laparoscopy group. An increased RAP was observed at 5 minutes (22.11 +/- 2.76 vs 28.8 +/- 3.68 mm Hg, P < .001), in the laparoscopic group and lower levels of "compliance" at the same moment in that group (16 +/- 1.66 vs 14.9 +/- 4.07 cm H2O). Laparoscopic nephrectomy caused an increase in CO and MAP and decreased SVR. Likewise there were elevations of RAP, ETCO2, and MV and a slight decrease in the "compliance."

Helium gas pneumoperitoneum can improve the recovery of gastrointestinal motility after a laparoscopic operation

The use of laparoscopic surgery contributes to faster recovery of postoperative gastrointestinal motility. Several authors have demonstrated the benefits of laparoscopic surgery using carbon dioxide (CO2) pneumoperitoneum. However, there have been few investigations of the effects of other insufflation gases on gastrointestinal motility. The aim of this study was to investigate the effect of CO2 and helium pneumoperitoneum on the recovery of postoperative gastrointestinal motility. For this study, male Sprague-Dawley rats were divided into four groups: control, CO2 insufflation (10 mmHg), helium insufflation (10 mmHg) and open laparotomy for one hour. Arterial pH values and PaCO2 were measured after surgery. Gastrointestinal motility was evaluated by quantifying the distribution of markers placed into the stomach at the end of procedures until 24 hours after surgery. In the CO2 insufflation group, the arterial pH value was significantly lower than that of the helium insufflation group, and significant hypercapnia persisted until six hours after surgery. The gastric emptying and transit time was significantly prolonged in the CO2 group compared with the helium insufflation group. This study demonstrates that helium pneumoperitoneum can improve the recovery of postoperative gastrointestinal motility because of the reduction of hypercapnia and a tendency to suffer acidosis compared with CO2 pneumoperitoneum.

Prospective randomized trial on low-pressure versus standard-pressure pneumoperitoneum in outpatient laparoscopic cholecystectomy

Inpatient low-pressure pneumoperitoneum laparoscopic cholecystectomy (LPLC) has been shown to have less postoperative pain (especially shoulder-tip pain). No report so far has documented the use of lower-pressure pneumoperitoneum in outpatient laparoscopic cholecystectomy (LC). A prospective randomized trial was conducted in Tung Wah Hospital, Day Surgery Centre from January 2004 to December 2004. A total of 40 patients were recruited and 20 of whom were allocated to each arm. Outcome measures included operation time, treatment-related morbidity, mortality, postoperative pain (eg, shoulder-tip pain), consumption of analgesics, and level of satisfaction. All patients in both groups could be discharged on the same day. Patients' demographics and operation time were comparable in both groups. There were no treatment-related morbidity and mortality, nor was there any significant difference in postoperative pain. Less shoulder-tip pain was observed in the LPLC group though without significant difference (5% vs. 20%; P=0.151). Three patients in the LPLC group needed higher insufflation pressure (12 mm Hg) because of inadequate exposure and adhesions, and the operations were successful in all of them. Otherwise, no conversion to open procedure was noted in both groups. The consumption of analgesics was minimal and a high level of satisfaction was achieved in both groups of patients. The present study demonstrated no difference in LPLC and standard-pressure pneumoperitoneum laparoscopic cholecystectomy in the outcomes of outpatient LC. Routine use of lower-pressure pneumoperitoneum in outpatient LC would not be recommended unless in selected straightforward cases.

Effects of increased intra-abdominal pressure on central circulation

BACKGROUND

In an experimental model we investigated the effects of a gradual increase in intra-abdominal pressure (IAP) on the central circulation.

METHODS

Seven pigs were anaesthetized, mechanically ventilated and instrumented. IAP was gradually increased by 5 mm Hg up to 30 mm Hg by abdominal banding in normovolaemic animals, and then they were made hypovolaemic after blood withdrawal. Right atrial pressure (RAP) and left ventricular end-diastolic pressure (LVEDP) at each step and aortic, femoral and inferior vena cava blood flows were measured. Left ventricular end-diastolic area (LVEDA) was determined using epicardial echocardiography.

RESULTS

Cardiac output maintained at mild IAP was reduced to 76 (24)% of the initial value at 30 mm Hg IAP [mean (sd)] in normovolaemic animals, and 72 (22)% (P<0.001) in hypovolaemic animals. In normovolaemic animals the LVEDA and LVEDP were significantly increased at an IAP of 10 and 15 mm Hg by 26 (24)% and 38 (23)%, respectively. At these IAP values, the difference between the RAP and IAP was positive. When this gradient became negative, that is beyond 15 mm Hg in normovolaemia and for all IAP values in hypovolaemic animals, the LVEDA declined, reaching 78 (16)% and 62 (22)% (P<0.05) of the initial values in normovolaemic and hypovolaemic groups at the highest IAP value.

CONCLUSIONS

These results showed that a gradual increase in IAP led to a redistribution of abdominal blood volume towards the thoracic compartment, at IAP lower than 15 mm Hg in normovolaemia, and at its expense at higher values of IAP. In hypovolaemia there was no thoracic compartment gain. Whereas the absolute or transmural RAPs were not informative of the direction of this blood shift, an RAP greater than IAP was associated with an intrathoracic compartment gain.

The effects of experimental venous carbon dioxide embolization on hemodynamic and respiratory variables

BACKGROUND

Laparoscopic liver resection is a relatively new surgical procedure. Carbon dioxide (CO2) pneumoperitoneum and laparoscopic liver dissection are recognized as risk factors for CO2 embolism to the pulmonary circulation. The embolization can be difficult to detect and can theoretically increase peri-operative morbidity. The aim of this study was to evaluate the cardiopulmonary effects in a pig model during a time period of 4 h after an experimental CO2 embolization.

METHODS

Eleven piglets were anesthesized. Nine were embolized with a single intravenous injection of 0.4 ml/kg CO2 and two served as controls. Respiratory and cardiovascular variables, including pulmonary artery pressure and cardiac output, were monitored for 4 h after embolization, and arterial blood gases were monitored on-line.

RESULTS

The embolized piglets had an increase in ventilatory dead space, pulmonary vascular resistance and pulmonary artery pressure and a decrease in cardiac output that lasted throughout the 4-h observation time. The mean arterial pressure and heart rate were unchanged. An early sign of embolization was a rapid fall in end-tidal CO2 and P(a)O2 and a rise in P(a)CO2.

CONCLUSION

Negative changes in cardiopulmonary physiology persisted for at least 4 h after a single intravenous CO2 injection, in spite of this gas being highly soluble in blood. This is a more prolonged influence of CO2 embolization than previously described. Extensive monitoring for early detection of an embolization may be recommended to limit morbidity in patients undergoing laparoscopic liver surgery.

A procedure-specific systematic review and consensus recommendations for postoperative analgesia following laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy has advantages over the open procedure for postoperative pain. However, a systematic review of postoperative pain management in this procedure has not been conducted.

METHODS

A systematic review was conducted according to the guidelines of the Cochrane Collaboration. Randomized studies examining the effect of medical or surgical interventions on linear pain scores in patients undergoing laparoscopic cholecystectomy were included. Qualitative and quantitative analyses were performed. Recommendations for patient care were derived from review of these data, evidence from other relevant procedures, and clinical practice observations collated by the Delphi method among the authors.

RESULTS

Sixty-nine randomized trials were included and 77 reports were excluded. Recommendations are provided for preoperative analgesia, anesthetic and operative techniques, and intraoperative and postoperative analgesia.

CONCLUSIONS

A step-up approach to the management of postoperative pain following laparoscopic cholecystectomy is recommended. This approach has been designed to provide adequate analgesia while minimizing exposure to adverse events.

Laparoscopic surgery: pitfalls due to anesthesia, positioning, and pneumoperitoneum

BACKGROUND

Laparoscopic procedures are increasing in number and extensiveness. Many patients undergoing laparoscopic surgery have coexisting disease. Especially in patients with cardiopulmonary comorbidity, pneumoperitoneum and positioning can be deleterious. This article reviews possible pitfalls related to the combination of anesthesia, positioning of the patient, and the influence of pneumoperitoneum in the course of laparoscopic interventions.

METHODS

A literature search using Medline's MESH terms was used to identify recent key articles. Cross-references from these articles were used as well.

RESULTS

Patient positioning and pneumoperitoneum can induce hemodynamic, pulmonary, renal, splanchnic, and endocrine pathophysiological changes, which will affect the entire perioperative period of patients undergoing laparoscopic procedures.

CONCLUSION

Perioperative management for the estimation and reduction of risk of morbidity and mortality due to surgery and anesthesia in laparoscopic procedures must be based on knowledge of the pathophysiological disturbances induced by the combination of general anesthesia, pneumoperitoneum, and positioning of the patient.