Positive end-expiratory pressure improves arterial oxygenation during prolonged pneumoperitoneum

Effect of ultrasound-guided transversus abdominis plane block in reducing atelectasis after laparoscopic surgery in children: A randomized clinical trial

Background

Atelectasis is a commonly observed postoperative complication of general anesthesia in children. Pulmonary protective ventilation strategies have been reported to have a beneficial effect on postoperative atelectasis in children. Therefore, the present study aimed to evaluate the efficacy of the ultrasound-guided transversus abdominis plane (TAP) block technique in preventing the incidence of postoperative atelectasis in children.

Materials and methods

This study enrolled 100 consecutive children undergoing elective laparoscopic bilateral hernia repair and randomly divided them into the control and TAP groups. Conventional lung-protective ventilation was initiated in both groups after the induction of general anesthesia. The children in the TAP group received an ultrasound-guided TAP block with 0.3 mL/kg of 0.5% ropivacaine after the induction of anesthesia.

Results

Anesthesia-induced atelectasis was observed in 24% and 84% of patients in the TAP (n = 50) and control (n = 50) groups, respectively, before discharge from the post-anesthetic care unit (T3; PACU) (odds ratio [OR], 0.062; 95% confidence interval [CI], 0.019-0.179; P < 0.001). No significant difference was observed between the control and TAP groups in terms of the lung ultrasonography (LUS) scores 5 min after endotracheal intubation (T1). However, the LUS scores were lower in the TAP group than those in the control group at the end of surgery (T2, P < 0.01) and before discharge from the PACU (T3, P < 0.001). Moreover, the ace, legs, activity, cry and consolability (FLACC) pain scores in the TAP group were lower than those in the control group at each postoperative time point.

Conclusion

Ultrasound-guided TAP block effectively reduced the incidence of postoperative atelectasis and alleviated pain in children undergoing laparoscopic surgery.

Airway leakage due to malpositioning of esophageal temperature probe during robot-assisted radical prostatectomy: a case report

Measuring patients' core body temperature during surgery is essential and commonly performed with an esophageal temperature probe. The probe must be placed in the lower third of the esophagus for accurate measurement. In this case report, we describe our experience of discovering an inadvertently malpositioned esophageal temperature probe in the right inferior lobar bronchus, which led to ventilation-related problems in a patient undergoing prostate surgery.

Machine learning model for predicting immediate postoperative desaturation using spirometry signal data

Postoperative desaturation is a common post-surgery pulmonary complication. The real-time prediction of postoperative desaturation can become a preventive measure, and real-time changes in spirometry data can provide valuable information on respiratory mechanics. However, there is a lack of related research, specifically on using spirometry signals as inputs to machine learning (ML) models. We developed an ML model and postoperative desaturation prediction index (DPI) by analyzing intraoperative spirometry signals in patients undergoing laparoscopic surgery. We analyzed spirometry data from patients who underwent laparoscopic, robot-assisted gynecologic, or urologic surgery, identifying postoperative desaturation as a peripheral arterial oxygen saturation level below 95%, despite facial oxygen mask usage. We fitted the ML model on two separate datasets collected during different periods. (Datasets A and B). Dataset A (Normal 133, Desaturation 74) was used for the entire experimental process, including ML model fitting, statistical analysis, and DPI determination. Dataset B (Normal 20, Desaturation 4) was only used for verify the ML model and DPI. Four feature categories-signal property, inter-/intra-position correlation, peak value/interval variability, and demographics-were incorporated into the ML models via filter and wrapper feature selection methods. In experiments, the ML model achieved an adequate predictive capacity for postoperative desaturation, and the performance of the DPI was unbiased.

The intraoperative management of robotic-assisted laparoscopic prostatectomy

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Effect of driving pressure-guided positive end-expiratory pressure on postoperative pulmonary complications in patients undergoing laparoscopic or robotic surgery: a randomised controlled trial

BACKGROUND

Individualised positive end-expiratory pressure (PEEP) improves respiratory mechanics. However, whether PEEP reduces postoperative pulmonary complications (PPCs) remains unclear. We investigated whether driving pressure-guided PEEP reduces PPCs after laparoscopic/robotic abdominal surgery.

METHODS

This single-centre, randomised controlled trial enrolled patients at risk for PPCs undergoing laparoscopic or robotic lower abdominal surgery. The individualised group received driving pressure-guided PEEP, whereas the comparator group received 5 cm H2O fixed PEEP during surgery. Both groups received a tidal volume of 8 ml kg-1 ideal body weight. The primary outcome analysed per protocol was a composite of pulmonary complications (defined by pre-specified clinical and radiological criteria) within 7 postoperative days after surgery.

RESULTS

Some 384 patients (median age: 67 yr [inter-quartile range: 61-73]; 66 [18%] female) were randomised. Mean (standard deviation) PEEP in patients randomised to individualised PEEP (n=178) was 13.6 cm H2O (2.1). Individualised PEEP resulted in lower mean driving pressures (14.7 cm H2O [2.6]), compared with 185 patients randomised to standard PEEP (18.4 cm H2O [3.2]; mean difference: -3.7 cm H2O [95% confidence interval (CI): -4.3 to -3.1 cm H2O]; P<0.001). There was no difference in the incidence of pulmonary complications between individualised (25/178 [14.0%]) vs standard PEEP (36/185 [19.5%]; risk ratio [95% CI], 0.72 [0.45-1.15]; P=0.215). Pulmonary complications as a result of desaturation were less frequent in patients randomised to individualised PEEP (8/178 [4.5%], compared with standard PEEP (30/185 [16.2%], risk ratio [95% CI], 0.28 [0.13-0.59]; P=0.001).

CONCLUSIONS

Driving pressure-guided PEEP did not decrease the incidence of pulmonary complications within 7 days of laparoscopic or robotic lower abdominal surgery, although uncertainty remains given the lower than anticipated event rate for the primary outcome.

CLINICAL TRIAL REGISTRATION

KCT0004888 (http://cris.nih.go.kr, registration date: April 6, 2020).

Lung-protective ventilation during Trendelenburg pneumoperitoneum surgery: A randomized clinical trial

Study objective To assess the effects of a protective ventilation strategy during Trendelenburg pneumoperitoneum surgery on postoperative oxygenation.

DESIGNS

Parallel-group, randomized trial.

SETTING

Operating room of a university hospital, Italy.

PATIENTS

Morbidly obese patients undergoing Trendelenburg pneumoperitoneum gynaecological surgery.

INTERVENTIONS

Participants were randomized to standard (SV: tidal volume = 10 ml/kg of predicted body weight, PEEP = 5 cmH₂O) or protective (PV: tidal volume = 6 ml/kg of predicted body weight, PEEP = 10 cmH₂O, recruitment maneuvers) ventilation during anesthesia.

MEASUREMENTS

Primary outcome was PaO₂/FiO₂ one hour after extubation. Secondary outcomes included day-1 PaO₂/FiO₂, day-2 respiratory function and intraoperative respiratory/lung mechanics, assessed through esophageal manometry, end-expiratory lung volume (EELV) measurement and pressure-volume curves.

MAIN RESULTS

Sixty patients were analyzed (31 in SV group, 29 in PV group). Median [IqR] tidal volume was 350 ml [300-360] in PV group and 525 [500-575] in SV group. Median PaO₂/FiO₂ one hour after extubation was 280 mmHg [246-364] in PV group vs. 298 [250-343] in SV group (p = 0.64). Day-1 PaO₂/FiO_2, day-2 forced vital capacity, FEV-1 and Tiffenau Index were not different between groups (all p > 0.10). Intraoperatively, 59% of patients showed complete airway closure during pneumoperitoneum, without difference between groups: median airway opening pressure was 17 cmH₂O. In PV group, airway and transpulmonary driving pressure were lower (12 ± 5 cmH₂O vs. 17 ± 7, p < 0.001; 9 ± 4 vs. 13 ± 7, p < 0.001), PaCO₂ and respiratory rate were higher (48 ± 8 mmHg vs. 42 ± 12, p < 0.001; 23 ± 5 breaths/min vs. 16 ± 4, p < 0.001). Intraoperative EELV was similar between PV and SV group (1193 ± 258 ml vs. 1207 ± 368, p = 0.80); ratio of tidal volume to EELV was lower in PV group (0.45 ± 0.12 vs. 0.32 ± 0.09, p < 0.001).

CONCLUSIONS

In obese patients undergoing Trendelenburg pneumoperitoneum surgery, PV did not improve postoperative oxygenation nor day-2 respiratory function. PV was associated with intraoperative respiratory mechanics indicating less injurious ventilation. The high prevalence of complete airway closure may have affected study results.

TRIAL REGISTRATION

Prospectively registered on http://clinicaltrials.govNCT03157479 on May 17th, 2017.

Surgical bleeding in patients undergoing posterior lumbar inter-body fusion surgery: a randomized clinical trial evaluating the effect of two mechanical ventilation mode types

BACKGROUND

The purpose of the study was to compare the effect of using volume-controlled ventilation (VCV) versus pressure-controlled ventilation (PCV) on blood loss in patients undergoing posterior lumbar inter-body fusion (PLIF) surgery.

METHODS

In a randomized, single-blinded, parallel design, 78 patients, candidates for PLIF surgery, were randomly allocated into two groups of 39 to be mechanically ventilated using VCV or PCV mode. All the patients were operated in prone position by one surgeon. Amount of intraoperative surgical bleeding, transfusion requirement, surgeon satisfaction, hemodynamic parameters, heart rate, and blood pressure were measured as outcomes.

RESULTS

PCV group showed slightly better outcomes than VCV group in terms of mean blood loss (431 cc vs. 465 cc), transfusion requirement (0.40 vs. 0.43 unit), and surgeon satisfaction (82.1% vs. 74.4%); however, the differences were not statistically significant. Diastolic blood pressure 90 and 105 min after induction were significantly lower in PCV group (P = 0.043-0.019, respectively); however, blood pressure at other times, hemoglobin levels, and mean heart rate were similar in two groups.

CONCLUSIONS

In patients undergoing posterior lumbar inter-body fusion surgery, mode of ventilation cannot make significant difference in terms of blood loss; however, some minor benefits in outcomes may lead to the selection of PCV rather than VCV. More studies with larger sample size, and investigating more factors may be needed.

Methods for Determination of Individual PEEP for Intraoperative Mechanical Ventilation Using a Decremental PEEP Trial

(1) Background: Individual PEEP settings (PEEPIND) may improve intraoperative oxygenation and optimize lung mechanics. However, there is uncertainty concerning the optimal procedure to determine PEEPIND. In this secondary analysis of a randomized controlled clinical trial, we compared different methods for PEEPIND determination. (2) Methods: Offline analysis of decremental PEEP trials was performed and PEEPIND was retrospectively determined according to five different methods (EIT-based: RVDI method, Global Inhomogeneity Index [GI], distribution of tidal ventilation [EIT VT]; global dynamic and quasi-static compliance). (3) Results: In the 45 obese and non-obese patients included, PEEPIND using the RVDI method (PEEPRVD) was 16.3 ± 4.5 cm H2O. Determination of PEEPIND using the GI and EIT VT resulted in a mean difference of −2.4 cm H2O (95%CI: −1.2;−3.6 cm H2O, p = 0.01) and −2.3 cm H2O (95% CI: −0.9;3.7 cm H2O, p = 0.01) to PEEPRVD, respectively. PEEPIND selection according to quasi-static compliance showed the highest agreement with PEEPRVD (p = 0.67), with deviations > 4 cm H2O in 3/42 patients. PEEPRVD and PEEPIND according to dynamic compliance also showed a high level of agreement, with deviations > 4 cm H2O in 5/42 patients (p = 0.57). (4) Conclusions: High agreement of PEEPIND determined by the RVDI method and compliance-based methods suggests that, for routine clinical practice, PEEP selection based on best quasi-static or dynamic compliance is favorable.

The effect of ultrasound-guided transversus abdominis plane block on pulmonary function in patients undergoing laparoscopic cholecystectomy: a prospective randomized study

BACKGROUND

Transversus abdominis plane block (TAPB) is commonly used for postoperative pain control after laparoscopic cholecystectomy. However, few studies have analyzed its effect on pulmonary function. The goal of this study was to elucidate the effect of ultrasound-guided bilateral TAPB on pulmonary function preservation and analgesia after laparoscopic cholecystectomy.

METHODS

We enrolled 58 patients who underwent laparoscopic cholecystectomy. Among them, 53 were randomized to group T (n = 27) and group C (n = 26). Group T and group C received ultrasound-guided bilateral TAPB with 40 ml of 0.375% ropivacaine and 40 ml of 0.9% normal saline, respectively. Visual analog scale (VAS) scores, patient-controlled analgesia (PCA) consumption, forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, peak expiratory flow rate (PEF), and modified Borg scale scores were measured until 24 h post-surgery.

RESULTS

The VAS scores were significantly lower in group T than in group C at 1 and 8 h after the surgery. PCA consumption was significantly lower in group T than in group C at all postoperative time points. FEV1, PEF, and FEV1/FVC were more preserved in group T than in group C at 1 h. Group T had significantly lower modified Borg scale scores than did group C at 1 and 8 h.

CONCLUSION

Ultrasound-guided TAPB is effective in pulmonary function preservation and pain control after laparoscopic cholecystectomy. Therefore, it could be a great option for multimodal analgesia, preservation of pulmonary function, prevention of pulmonary complications including atelectasis, and promotion of postoperative recovery after laparoscopic cholecystectomy.

CLINICAL REGISTRATION

This study was enrolled in the Clinical Research Information Service (Clinical Research Information Service, KCT0004435, Hwa Yong Shin, 2019-08-19).

Management of Intraoperative Mechanical Ventilation to Prevent Postoperative Complications after General Anesthesia: A Narrative Review

Mechanical ventilation (MV) is still necessary in many surgical procedures; nonetheless, intraoperative MV is not free from harmful effects. Protective ventilation strategies, which include the combination of low tidal volume and adequate positive end expiratory pressure (PEEP) levels, are usually adopted to minimize the ventilation-induced lung injury and to avoid post-operative pulmonary complications (PPCs). Even so, volutrauma and atelectrauma may co-exist at different levels of tidal volume and PEEP, and therefore, the physiological response to the MV settings should be monitored in each patient. A personalized perioperative approach is gaining relevance in the field of intraoperative MV; in particular, many efforts have been made to individualize PEEP, giving more emphasis on physiological and functional status to the whole body. In this review, we summarized the latest findings about the optimization of PEEP and intraoperative MV in different surgical settings. Starting from a physiological point of view, we described how to approach the individualized MV and monitor the effects of MV on lung function.

Effects of an Alveolar Recruitment Maneuver During Lung Protective Ventilation on Postoperative Pulmonary Complications in Elderly Patients Undergoing Laparoscopy

Purpose

Controversy remains over whether alveolar recruitment maneuvers (ARMs) can reduce postoperative pulmonary complications. We hypothesized that performing an ARM in addition to lung protective ventilation (LPV) could improve intraoperative arterial oxygenation and postoperative pulmonary complications (PPCs) in elderly patients undergoing laparoscopy in the Trendelenburg position.

Patients and Methods

Sixty-two patients (aged 65-85) scheduled for laparoscopic low anterior resection were randomized to receive LPV only (LPV group, n = 32) or LPV with an ARM (ARM group, n = 30). LPV was set to a tidal volume of 6 mL/kg with a positive end expiratory pressure (PEEP) of 5 cmH₂O. The ARM was performed by serially increasing the PEEP to 10 cmH₂O for 3 breaths, 15 cmH₂O for 3 breaths, then 20 cmH₂O for 10 breaths, both immediately before and after abdominal insufflation. The primary end-point was the frequency of PPCs such as desaturation (SpO₂ <90%), atelectasis, and pneumonia. Secondary end-points were changes in intraoperative respiratory and gas exchange parameters and hemodynamic variables.

Results

One patient in the LPV group experienced desaturation on the first postoperative day. The frequency of chest X-ray abnormalities such as atelectasis or pleural effusion was comparable between groups (6 (19%) and 5 (17%) patients, respectively, P = 0.676). Changes in other respiratory, gas exchange and hemodynamic parameters over time were not significantly different between the groups. However, vasopressor requirements during surgery were higher in the ARM than the LPV group (9 (30%) and 2 (6%) patients, respectively, P = 0.014).

Conclusion

This study suggests that performing an ARM during LPV may not improve postoperative respiratory outcomes and intraoperative oxygenation compared to LPV alone in geriatric patients undergoing laparoscopy in the Trendelenburg position. In addition, since the ARM could cause a significant deterioration in hemodynamic parameters, applying ARM to elderly patients should be carefully considered.

Effect of Different Levels of Positive End-Expiratory Pressure (PEEP) on Respiratory Status during Gynecologic Laparoscopy

Background

During gynecologic laparoscopy, pneumoperitoneum, and the position of the patient's head can lead to pathophysiologic changes in cardiovascular and respiratory systems, complicating the management of anesthesia in these patients. One of the strategies for improving the respiratory status of patients undergoing laparoscopy is the use of Positive End-Expiratory Pressure (PEEP).

Objectives

This study aimed to evaluate the effect of different levels of PEEP on the respiratory status of patients undergoing gynecologic laparoscopy.

Methods

In this clinical trial, 60 patients with ASA I were randomly assigned to three groups to control anesthesia: ZEEP (PEEP 0 cmH₂O; 20 cases), PEEP₅ (PEEP 5 cmH₂O; 20 cases), and PEEP₁₀ (PEEP 10 cmH₂O; 20 cases). Respiratory and hemodynamic variables of patients were compared before general anesthetic induction and immediately after CO₂ insufflation at intervals of 5, 10, 20, 30, and 60 min and the end of the operation in the three study groups.

Results

The PEEP application improved pH, PaCO₂, and PaO₂ levels at the end of pneumoperitoneum compared to baseline when compared with the non-use of PEEP (ZEEP group). Also, the frequency of dysrhythmia in the use of PEEP in controlled ventilation was significantly lower in patients with PEEP₁₀ (P < 0.05). The application of PEEP₅ resulted in similar effects to PEEP₁₀ in the levels of respiratory variables.

Conclusions

The PEEP application is associated with improved arterial blood gas in patients with gynecologic laparoscopy. The use of PEEP₁₀ has a greater effect on the improvement of respiratory parameters and complications of pneumoperitoneum.

Effects of intra-operative positive end-expiratory pressure setting guided by oesophageal pressure measurement on oxygenation and respiratory mechanics during laparoscopic gynaecological surgery: A randomised controlled trial

BACKGROUND

The creation of pneumoperitoneum during laparoscopic surgery can lead to adverse effects on the respiratory system. Positive end-expiratory pressure (PEEP) plays an important role in mechanical ventilation during laparoscopic surgery.

OBJECTIVE

To evaluate whether PEEP setting guided by oesophageal pressure (Poeso) measurement would affect oxygenation and respiratory mechanics during laparoscopic gynaecological surgery.

DESIGN

A randomised controlled study.

SETTING

A single-centre trial from March 2018 to June 2018.

PATIENTS

Forty-four adult patients undergoing laparoscopic gynaecological surgery with anticipated duration of surgery more than 2 h.

INTERVENTION

PEEP set according to Poeso measurement (intervention group) versus PEEP constantly set at 5 cmH2O (control group).

MAIN OUTCOME MEASURES

Gas exchange and respiratory mechanics after induction and intubation (T0) and at 15 and 60 min after initiation of pneumoperitoneum (T1 and T2, respectively).

RESULTS

PEEP during pneumoperitoneum was significantly higher in the intervention group than in the control group (T1, 12.5 ± 1.9 vs. 5.0 ± 0.0 cmH2O and T2, 12.4 ± 1.9 vs. 5.0 ± 0.0 cmH2O, both P < 0.001). Partial pressures of oxygen decreased significantly from baseline during pneumoperitoneum in the control group but not in the intervention group. Nevertheless, the changes in partial pressures of oxygen did not differ between groups. Compliance of the respiratory system (CRS) significantly decreased and driving pressure significantly increased during pneumoperitoneum in both groups. However, the changes in CRS and driving pressure were significantly less in the intervention group. Transpulmonary pressure during expiration was maintained in the intervention group while it decreased significantly in the control group.

CONCLUSION

PEEP setting guided by Poeso measurement showed no beneficial effects in terms of oxygenation but respiratory mechanics were better during laparoscopic gynaecological surgery.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03256396.

Parâmetros hemodinâmicos e ventilatórios em coelhos anestesiados com isoflurano, submetidos à ventilação controlada à pressão com ou sem PEEP

RESUMO Foi comparada a ventilação controlada à pressão com ou sem pressão positiva expiratória final (PEEP), em coelhos, distribuídos em três grupos, denominados GP (grupo ventilação ciclada à pressão), GPP (grupo ventilação ciclada à pressão com PEEP) e GE (grupo ventilação espontânea - grupo controle). Os animais foram anestesiados com isoflurano, em circuito com reinalação de gases, durante duas horas. As médias de pressão arterial média (PAM) e pressão arterial sistólica (PAS) permaneceram discretamente abaixo dos valores normais em todos os grupos. Houve diminuição significativa da PAM e da PAS no grupo submetido à PEEP (GPP) ao longo do tempo. A pressão parcial de dióxido de carbono arterial (PaCO2) foi maior no GPP quando comparado aos outros grupos no último momento, gerando acidemia respiratória após uma hora de procedimento. A concentração de dióxido de carbono ao final da expiração (ETCO2) apresentou médias discretamente elevadas no grupo não tratado com PEEP (GP) e no grupo controle, enquanto o GPP apresentou maiores médias, possivelmente, relacionadas à diminuição do volume corrente neste grupo. Com base nesses resultados, foi possível concluir que a utilização da PEEP levou à acidemia, que se agravou ao longo do tempo anestésico. Ademais, a anestesia prolongada com isoflurano promove depressão cardiorrespiratória, independentemente do modo ventilatório empregado.

The effects of a recruitment manoeuvre with positive end-expiratory pressure on lung compliance in patients undergoing robot-assisted laparoscopic radical prostatectomy

The effects of a recruitment manoeuvre (RM) with positive end-expiratory pressure (PEEP) on lung compliance (C_LUNG) are not well characterised in robot-assisted laparoscopic radical prostatectomy (RARP). Patients were allocated to group R (n = 10; with an RM) or C (n = 9; without an RM). An RM involved sustained inflation of 30 cmH₂O for 30 s. The lungs were ventilated with volume-controlled ventilation with tidal volume of 7 mL kg^-1 of predicted body weight and fraction of inspired oxygen of 0.5. End-tidal carbon dioxide pressure was maintained at normocapnia. Patients were in the horizontal lithotomy position (pre-op). After pneumoperitoneum, patients underwent RARP in a steep Trendelenburg lithotomy position at a PEEP level of 0 cmH₂O (RARP0). An RM was used in the R group but not in the C group. Patients were then ventilated with 5 cmH₂O PEEP for 1 h after RARP0 (RARP5.1) and 2 h after RARP0 (RARP5.2). Oesophageal pressure and airway pressure were measured for calculating C_LUNG and chest wall compliance. C_LUNG significantly decreased from pre-op to RARP0 and did not significantly increase from RARP0 to RARP5.1 and RARP5.2 in either group. C_LUNG differed significantly between groups at RARP5.1 and RARP5.2 (103 ± 30 vs. 68 ± 11 mL cm^-1 H₂O and 106 ± 35 vs. 72 ± 9 mL cm^-1 H₂O; P < 0.05). In patients undergoing RARP, with the addition of RM, the C_LUNG was effectively increased from the horizontal lithotomy position to the steep Trendelenburg lithotomy position under pneumoperitoneum.

Does Lung Compliance Optimization Through PEEP Manipulations Reduce the Incidence of Postoperative Hypoxemia in Laparoscopic Bariatric Surgery? A Randomized Trial

BACKGROUND

In obese patients (OP), the best intraoperative ventilation strategy remains to be defined. Dynamic lung compliance (C_dyn) and dead space fraction are indicators of efficient ventilation at an optimal positive end-expiratory pressure (PEEP). Herein, we investigated whether intraoperative dynamic lung compliance optimization through PEEP manipulations affects the incidence of postoperative hypoxemia (SpO₂ < 90%) in OP undergoing laparoscopic bariatric surgery (LBS).

METHODS

This was a single-center, prospective, randomized controlled study conducted from July 2013 to December 2015. After obtaining institutional review board approval and informed consent, 100 OP undergoing LBS under volume-controlled ventilation (tidal volume 8 mL/kg of ideal body weight) were randomized according to the PEEP level maintained during the surgery. In the control group, a PEEP of 10 cm H₂O was maintained, while in the intervention group, the PEEP was adapted to achieve the best dynamic lung compliance. Anesthesia and analgesia were standardized. The patients received supplemental nasal oxygen on the first postoperative day and were monitored up to the second postoperative day with a portable pulse oximeter.

RESULTS

Demographics were similar between groups. There was no difference in the incidence of hypoxemia during the first 2 postoperative days (control: 1.3%; intervention: 2.1%; p = 0.264).

CONCLUSIONS

The incidence of postoperative hypoxemia was not reduced by an open-lung approach with protective ventilation strategy in obese patients undergoing LBS. A pragmatic application of a PEEP level of 10 cm H₂O was comparable to individual PEEP titration in these patients.

TRIAL REGISTRATION

Clinicaltrials.gov identifier, NCT02579798; https://clinicaltrials.gov/ct2/show/NCT02579798.

Volume-Controlled Versus Dual-Controlled Ventilation during Robot-Assisted Laparoscopic Prostatectomy with Steep Trendelenburg Position: A Randomized-Controlled Trial

Dual-controlled ventilation (DCV) combines the advantages of volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV). Carbon dioxide (CO₂) pneumoperitoneum and steep Trendelenburg positioning for robot-assisted laparoscopic radical prostatectomy (RALRP) has negative effects on the respiratory system. We hypothesized that the use of autoflow as one type of DCV can reduce these effects during RALRP. Eighty patients undergoing RALRP were randomly assigned to receive VCV or DCV. Arterial oxygen tension (PaO₂) as the primary outcome, respiratory and hemodynamic data, and postoperative fever rates were compared at four time points: 10 min after anesthesia induction (T1), 30 and 60 min after the initiation of CO₂ pneumoperitoneum and Trendelenburg positioning (T2 and T3), and 10 min after supine positioning (T4). There were no significant differences in PaO₂ between the two groups. Mean peak airway pressure (Ppeak) was significantly lower in group DCV than in group VCV at T2 (mean difference, 5.0 cm H₂O; adjusted p < 0.001) and T3 (mean difference, 3.9 cm H₂O; adjusted p < 0.001). Postoperative fever occurring within the first 2 days after surgery was more common in group VCV (12%) than in group DCV (3%) (p = 0.022). Compared with VCV, DCV did not improve oxygenation during RALRP. However, DCV significantly decreased Ppeak without hemodynamic instability.

Comparative effects of open-lung positive end-expiratory pressure (PEEP) and fixed PEEP on respiratory system compliance in the isoflurane anaesthetised healthy dog

This study was performed to assess the effects of open-lung positive end-expiratory pressure (OL-PEEP) following stepwise recruitment manoeuvre (RM) and those of a fixed PEEP of 5 cm H₂O without previous RM on respiratory system compliance (Crs) and selected cardiovascular variables in healthy dogs under general anaesthesia. Forty-five healthy client-owned dogs undergoing surgery were anaesthetised and mechanically ventilated (tidal volume, VT = 10-12 mL/kg; PEEP = 0 cm H₂O) for 1 min (baseline) and randomly allocated into zero positive end-expiratory pressure (ZEEP), PEEP (5 cm H₂O) and OL-PEEP treatment groups. In the OL-PEEP group, a stepwise RM was performed and the individual OL-PEEP was subsequently applied. The Crs, heart rate (HR) and non-invasive mean arterial pressure (NIMAP) were registered at baseline and then every 10 min during 60 min. In the ZEEP group, Crs decreased from baseline. In the PEEP group, Crs was not different from either baseline or ZEEP group values. In the OL-PEEP group, Crs was higher than both baseline and ZEEP group values at all time points as well as of those in the PEEP group during at least 20 min after RM. There were no differences for HR and NIMAP between groups. A clinically relevant hypotension following RM was observed in 40% of dogs. Therefore, an individually set OL-PEEP following stepwise RM improved Crs in anaesthetised healthy dogs, although transient but clinically relevant hypotension was observed during RM in some dogs. Fixed PEEP of 5 cm H₂O without previous RM did not improve Crs, although it prevented it from decreasing.

Comparison of the effects of different positive end-expiratory pressure levels on respiratory mechanics and oxygenation in laparoscopic surgery: A protocol for systematic review and network meta-analyses

BACKGROUND

Several studies have observed the good effects of positive end-expiratory pressure (PEEP) application in laparoscopic surgeries, such as counteracted intraoperative atelectasis, improved respiratory mechanics, and gas exchange. However, evidence of systematic comparisons of different PEEP levels is short, and the optimal level of PEEP during laparoscopy remains unknown and controversial. The study aims to compare the effects of different PEEP levels on respiratory mechanics and oxygenation in laparoscopic surgery using network meta-analyses.

METHODS

To identify relevant studies, a systematic search will be conducted among electronic databases, including PubMed, Cochrane Library, EMBASE, and Web of Science. We will include randomized controlled trials (RCTs). The risk of bias in the included RCTs will be assessed using the Cochrane bias risk tool. Network meta-analysis will be performed using STATA 15.0, and R 3.4.1 software.

RESULTS

This study is ongoing and the results will be published in a peer-reviewed journal.

CONCLUSION

The results of this study will be sent to clinicians and healthcare providers in the National Health Service, which is expected to help clinicians make more informed treatment decisions and facilitate further research on the use of PEEP during surgery.

PROSPERO REGISTRATION NUMBER

CRD42018093537.

Perioperative lung protective ventilation

Perioperative lung injury is a major source of postoperative morbidity, excess healthcare use, and avoidable mortality. Many potential inciting factors can lead to this condition, including intraoperative ventilator induced lung injury. Questions exist as to whether protective ventilation strategies used in the intensive care unit for patients with acute respiratory distress syndrome are equally beneficial for surgical patients, most of whom do not present with any pre-existing lung pathology. Studied both individually and in combination as a package of intraoperative lung protective ventilation, the use of low tidal volumes, moderate positive end expiratory pressure, and recruitment maneuvers have been shown to improve oxygenation and pulmonary physiology and to reduce postoperative pulmonary complications in at risk patient groups. Further work is needed to define the potential contributions of alternative ventilator strategies, limiting excessive intraoperative oxygen supplementation, use of non-invasive techniques in the postoperative period, and personalized mechanical ventilation. Although the weight of evidence strongly suggests a role for lung protective ventilation in moderate risk patient groups, definitive evidence of its benefit for the general surgical population does not exist. However, given the shift in understanding of what is needed for adequate oxygenation and ventilation under anesthesia, the largely historical arguments against the use of intraoperative lung protective ventilation may soon be outdated, on the basis of its expanding track record of safety and efficacy in multiple settings.

Complications of CO2 insufflation during endoscopic vein harvesting

Over the past few decades, the use of endoscopic harvest of the saphenous vein has gained popularity due to a significant reduction in rates of wound infection and improved cosmesis. The widespread adoption of this technique has introduced a set of complications associated with the use CO₂ insufflation which facilitates exposure during the vein harvest. We describe a case of pneumoperitoneum with systemic acidosis and subcutaneous air following endoscopic vein harvest for coronary artery bypass grafting and review the complications that may arise from CO₂ insufflation during endoscopic vein harvesting.

What is the proper ventilation strategy during laparoscopic surgery?

The main stream of intraabdominal surgery has changed from laparotomy to laparoscopy, but anesthetic care for laparoscopic surgery is challenging for clinicians, because pneumoperitoneum might aggravate respiratory mechanics and arterial oxygenation. The authors reviewed the literature regarding ventilation strategies that reduce deleterious pulmonary physiologic changes during pneumoperitoneum for laparoscopic surgery under general anesthesia and make appropriate recommendations.

Effects of positive end-expiratory pressure on intracranial pressure during pneumoperitoneum and Trendelenburg position in a porcine mode

Background/aim: This study was undertaken to evaluate the effects of positive end-expiratory pressure (PEEP) levels on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) and to determine the appropriate PEEP level during steep Trendelenburg position combined with pneumoperitoneum.Materials and methods: Ten pigs were included in this study. Pneumoperitoneum and Trendelenburg position were maintained and PEEP titration was initiated. Arterial pressure, heart rate, arterial blood gas, ICP, and CPP were recorded at the following time points: baseline (T0), 30 min after positioning and pneumoperitoneum (T1), PEEP 5 (T2), PEEP 10 (T3), PEEP 15 (T4), and PEEP 20 (T5).Results: MAP significantly increased at T1 compared to T0 and decreased at T4 and T5 compared to T1. ICP was 9.5 mmHg and CPP was 69.3 mmHg at T0. CO2 insufflation and steep Trendelenburg position did not cause any significant difference in ICP and CPP. ICP increased and CPP decreased significantly at T4 and T5 compared to both T0 and T1. PaO2 and PaO2/FiO2 decreased significantly at T1 and T2 compared to T0, while both increased significantly at T3, T4, and T5 compared to T1.Conclusion: PEEP of 10 cmH2O was effective for providing oxygenation while preserving hemodynamic stability, ICP, and CPP in this model.

Association of pre-operative estimated GFR on post-operative pulmonary complications in laparoscopic surgeries

Despite a large body of evidence showing the pandemic of chronic kidney disease, the impact of pre-operative kidney function on the risk of post-operative pulmonary complications (PPCs) is not well known. We used multivariable logistic regression analyses with 3-level hierarchical adjustments to identify the association of pre-operative estimated glomerular filtration rate (eGFR) with PPCs in laparoscopic surgeries. Among 452,213 patients between 2005 and 2013 in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) Database, a total of 3,727 patients (0.9%) experienced PPCs. We found a gradient association between lower eGFR and higher likelihood of PPCs in the unadjusted model. In the case-mix adjusted model, a reverse-J-shaped association was observed; a small albeit significant association with the highest eGFR category emerged. Further adjustment slightly attenuated these associations, but the PPCs risk in the eGFR groups of <30, 30-60, and ≥120 mL/min/1.73 m2 remained significant: odds ratios (95% confidence intervals) of 1.82 (1.54-2.16), 1.38 (1.24-1.54), and 1.28 (1.07-1.53), respectively (reference: 90-120 mL/min/1.73 m2). Our findings propose a need for careful pre-operative evaluation of cardiovascular and pulmonary functions and post-operative fluid management among patients with not only lower but also very high eGFR.

The Effects of Positive End-Expiratory Pressure at Different Levels on Postoperative Respiration Parameters in Patients Undergoing Laparoscopic Cholecystectomy

Purpose/Aim of the study: We investigated the effects of different positive end-expiratory pressure (PEEP) levels on postoperative respiration parameters in patients undergoing laparoscopic cholecystectomy.

MATERIALS AND METHODS

One hundred and five consecutive patients were randomly divided to three groups (n = 35, for each group). Group I did not receive PEEP whereas group II received PEEP as 5 cmH₂O and group III received PEEP as 8 cm H₂O. Measurements with spirometer were taken 1 hour before the operation (T₁) and, 1 (T₂), 6 (T₃), and 24 hours (T₄) after extubation by an anesthetist. Forced expiratory volume (FEV₁), forced vital capacity (FVC), and peak expiratory flow (PEF) were recorded.

RESULTS

Group I had higher FVC values measured at T₂ time point compared with other groups (p < 0.05, for both groups). There was a statistically significant difference between group I and group III in terms of the FVC values measured at T₃ and T₄ time points (p = 0.05 and p < 0.05, retrospectively). A statistical difference was found between group I and group II in terms of FEV₁ measured at T₂ time point (p < 0.05). Group I had higher FEV₁ values measured at T₃ and T₄ time points compared to group III (p = 0.05, P<0.05; respectively). Group III had lower PEF values measured at T₄ time point compared to group I and II (p < 0.05).

CONCLUSIONS

We concluded that PEEP with 5 or 8 cmH₂O has negative effects on lung function tests measured with spirometer during postoperative 1^st, 6^th, and 24^th hours in patients underwent elective laparoscopic cholecystectomy.

Positive end-expiratory pressure does not decrease cardiac output during laparoscopic liver surgery: A prospective observational evaluation

BACKGROUND

Positive end-expiratory pressure (PEEP) has beneficial pulmonary effects but may worsen the hemodynamic repercussions induced by pneumoperitoneum (PNP) in patients undergoing laparoscopic liver resection. However, by increasing intraluminal vena cava (VC) pressures, PEEP may prevent PNP-induced VC collapse. The aim of this study was to test the validity of this hypothesis.

METHODS

After IRB approval and written informed consent, 20 patients were evaluated prospectively. Measurements were performed before and after the application of 10 cmH₂O PEEP on patients without PNP (Control group) and during a 12 cmH₂0 PNP. Results are provided as means [95%CI]. Comparison used paired-sample t test.

RESULTS

PEEP induced a decrease in CI in Control subgroup (2.3 [2.0-2.6] and 2.1 [1.8-2.4] l min^-1 m^-2 before and after PEEP. P < 0.05). In contrast, PEEP on a pre-established PNP did not significantly modify cardiac index (CI). Transmural pressure on the abdominal vena cava decreased with PNP but was partly reversed by the addition of PEEP.

CONCLUSION

The application of PEEP on a pre-established PNP during laparoscopic liver resection in normovolemic patients did not decrease CI. Analysis of transmural VC pressure variations confirms that the addition of PEEP may prevent the vena caval collapse induced by PNP.

Effects of different levels of end-expiratory pressure on hemodynamic, respiratory mechanics and systemic stress response during laparoscopic cholecystectomy

OBJECTIVE

General anesthesia causes reduction of functional residual capacity. And this decrease can lead to atelectasis and intrapulmonary shunting in the lung. In this study we want to evaluate the effects of 5 and 10cmH₂O PEEP levels on gas exchange, hemodynamic, respiratory mechanics and systemic stress response in laparoscopic cholecystectomy.

METHODS

American Society of Anesthesiologist I-II physical status 43 patients scheduled for laparoscopic cholecystectomy were randomly selected to receive external PEEP of 5cmH₂O (PEEP 5 group) or 10cmH₂O PEEP (PEEP 10 group) during pneumoperitoneum. Basal hemodynamic parameters were recorded, and arterial blood gases (ABG) and blood sampling were done for cortisol, insulin and glucose level estimations to assess the systemic stress response before induction of anesthesia. Thirty minutes after the pneumoperitoneum, the respiratory and hemodynamic parameters were recorded again and ABG and sampling for cortisol, insulin, and glucose levels were repeated. Lastly hemodynamic parameters were recorded; ABG analysis and sampling for stress response levels were taken after 60minutes from extubation.

RESULTS

There were no statistical differences between the two groups about hemodynamic and respiratory parameters except mean airway pressure (P_mean). P_mean, compliance and PaO₂; pH values were higher in 'PEEP 10 group'. Also, PaCO₂ values were lower in 'PEEP 10 group'. No differences were observed between insulin and lactic acid levels in the two groups. But postoperative cortisol level was significantly lower in 'PEEP 10 group'.

CONCLUSION

Ventilation with 10cmH₂O PEEP increases compliance and oxygenation, does not cause hemodynamic and respiratory complications and reduces the postoperative stress response.

Effects of intraoperative protective lung ventilation on postoperative pulmonary complications in patients with laparoscopic surgery: prospective, randomized and controlled trial

BACKGROUND

Respiratory functions are usually impaired during pneumoperitoneum for laparoscopic surgery. This randomized, controlled and single-blinded study was performed to evaluate whether intraoperative protective lung ventilation influences postoperative pulmonary complications after laparoscopic hepatobiliary surgery.

METHODS

Sixty-two patients were randomized to receive either conventional ventilation with alveolar recruitment maneuver (tidal volume of 10 ml/kg with inspiratory pressure of 40 cmH2O for 30 s after the end of pneumoperitoneum, group R), or protective lung ventilation (low tidal volume of 6 ml/kg with positive end-expiratory pressure [PEEP] of 5 cmH2O, group P). Induction and maintenance of anesthesia were done with balanced anesthesia. Respiratory complications such as atelectasis, pneumonia or desaturation were observed postoperatively. The length of hospital stay, arterial blood gas analysis, peak inspiratory pressure and hemodynamic variables were also recorded. Results are presented as mean ± SD or number of patients (%).

RESULTS

Postoperative pulmonary complications (P = 0.023) and desaturation below 90 % (P = 0.016) occurred less frequently in group P than in group R. Eight patients of group R and 3 patients of group P showed atelectasis. Pneumonia was diagnosed in 1 patient of group R. No differences were observed in the length of hospital stay, arterial blood gas analysis (pH, PaO2, PaCO2 and PAO2) and hemodynamic variables except PAO2, AaDO2 and peak inspiratory pressure between the two groups.

CONCLUSION

Protective lung ventilation (low tidal volume with PEEP) during pneumoperitoneum was associated with less incidences of pulmonary complications than conventional ventilation with alveolar recruitment maneuver after laparoscopic hepatobiliary surgery.

Respiratory management of the obese patient undergoing surgery

As a reflection of the increasing global incidence of obesity, there has been a corresponding rise in the proportion of obese patients undergoing major surgery. This review reports the physiological effect of these changes in body composition on the respiratory system and discusses the clinical approach required to maximize safety and minimize the risk to the patient. The changes in respiratory system compliance and lung volumes, which can adversely affect pulmonary gas exchange, combined with upper airways obstruction and sleep-disordered breathing need to be considered carefully in the peri-operative period. Indeed, these challenges in the obese patient have led to a clear focus on the clinical management strategy and development of peri-operative pathways, including pre-operative risk assessment, patient positioning at induction and under anesthesia, modified approach to intraoperative ventilation and the peri-operative use of non-invasive ventilation (NIV) and continuous positive airways pressure.

Cardiorespiratory effects of balancing PEEP with intra-abdominal pressures during laparoscopic cholecystectomy

BACKGROUND

Applying appropriate positive end-expiratory pressure (PEEP) to corresponding intra-abdominal pressure (IAP) can improve gas exchange during capnoperitoneum without any hemodynamic effects.

MATERIALS AND METHODS

A total of 75 patients were randomly allocated to group 0PEEP (n=25), group 5PEEP (n=25), and group 10PEEP (n=25) according to the level of PEEP, in whom capnoperitoneum was created with IAP of 14, 8, and 14 mm Hg, respectively. Hemodynamic and respiratory parameters were recorded up to 30 minutes after capnoperitoneum.

RESULTS

In 0PEEP group, mean end-tidal carbon dioxide demonstrated significant rise 2 minutes after capnoperitoneum and plateaued at about 15 minutes but remained at high level for up to 30 minutes when compared with the 5PEEP and 10PEEP groups (P<0.05). Correspondingly, the mean PaCO2 (48.0±4.1 mm Hg) for the 0PEEP group was higher at 30 minutes when compared with 5PEEP (37.8±2.7 mm Hg) and 10PEEP (37.2±3.9 mm Hg) groups. The oxygenation was better preserved in 5PEEP and 10PEEP groups with significantly higher PaO2/Fio2 ratio. Heart rate, mean arterial pressure, and cardiac output remained stable throughout the study in all the 3 groups.

CONCLUSIONS

Application of appropriate PEEP corresponding to the IAP helped maintain CO2 elimination and improved oxygenation without any hemodynamic disturbance in patients undergoing laparoscopic cholecystectomy.

Positive end-expiratory pressure (PEEP) during anaesthesia for prevention of mortality and postoperative pulmonary complications

BACKGROUND

General anaesthesia causes atelectasis, which can lead to impaired respiratory function. Positive end-expiratory pressure (PEEP) is a mechanical manoeuvre that increases functional residual capacity (FRC) and prevents collapse of the airways, thereby reducing atelectasis. It is not known whether intraoperative PEEP alters the risks of postoperative mortality and pulmonary complications. This review was originally published in 2010 and was updated in 2013.

OBJECTIVES

To assess the benefits and harms of intraoperative PEEP in terms of postoperative mortality and pulmonary outcomes in all adult surgical patients.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) 2013, Issue 10, part of The Cochrane Library, as well as MEDLINE (via Ovid) (1966 to October 2013), EMBASE (via Ovid) (1980 to October 2013), CINAHL (via EBSCOhost) (1982 to October 2013), ISI Web of Science (1945 to October 2013) and LILACS (via BIREME interface) (1982 to October 2010). The original search was performed in January 2010.

SELECTION CRITERIA

We included randomized clinical trials assessing the effects of PEEP versus no PEEP during general anaesthesia on postoperative mortality and postoperative respiratory complications in adults, 16 years of age and older.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected papers, assessed trial quality and extracted data. We contacted study authors to ask for additional information, when necessary. We calculated the number of additional participants needed (information size) to make reliable conclusions.

MAIN RESULTS

This updated review includes two new randomized trials. In total, 10 randomized trials with 432 participants and four comparisons are included in this review. One trial had a low risk of bias. No differences were demonstrated in mortality, with risk ratio (RR) of 0.97 (95% confidence interval (CI) 0.20 to 4.59; P value 0.97; 268 participants, six trials, very low quality of evidence (grading of recommendations assessment, development and evaluation (GRADE)), and in pneumonia, with RR of 0.40 (95% CI 0.11 to 1.39; P value 0.15; 120 participants, three trials, very low quality of evidence (GRADE)). Statistically significant results included the following: The PEEP group had higher arterial oxygen pressure (PaO2)/fraction of inspired oxygen (FiO2) on day one postoperatively, with a mean difference of 22.98 (95% CI 4.40 to 41.55; P value 0.02; 80 participants, two trials, very low quality of evidence (GRADE)), and postoperative atelectasis (defined as an area of collapsed lung, quantified by computerized tomography scan) was less in the PEEP group (standard mean difference -1.2, 95% CI -1.78 to -0.79; P value 0.00001; 88 participants, two trials, very low quality of evidence (GRADE)). No adverse events were reported in the three trials that adequately measured these outcomes (barotrauma and cardiac complications). Using information size calculations, we estimated that a further 21,200 participants would have to be randomly assigned to allow a reliable conclusion about PEEP and mortality.

AUTHORS' CONCLUSIONS

Evidence is currently insufficient to permit conclusions about whether intraoperative PEEP alters risks of postoperative mortality and respiratory complications among undifferentiated surgical patients.

PEEP role in ICU and operating room: from pathophysiology to clinical practice

Positive end expiratory pressure (PEEP) may prevent cyclic opening and collapsing alveoli in acute respiratory distress syndrome (ARDS) patients, but it may play a role also in general anesthesia. This review is organized in two sections. The first one reports the pathophysiological effect of PEEP on thoracic pressure and hemodynamic and cerebral perfusion pressure. The second section summarizes the knowledge and evidence of the use of PEEP in general anesthesia and intensive care. More specifically, for intensive care this review refers to ARDS and traumatic brain injured patients.

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.

Optimal positive end-expiratory pressure during robot-assisted laparoscopic radical prostatectomy

BACKGROUND

Increased intra-abdominal pressure during laparoscopic surgery causes cephalad displacement of the diaphragm, resulting in the formation of atelectasis, which can be overcome by positive end-expiratory pressure (PEEP). The aim of this prospective study was to investigate the level of optimal PEEP to maintain adequate arterial oxygenation and hemodynamics during robot-assisted laparoscopic radical prostatectomy (RLRP).

METHODS

One hundred patients undergoing RLRP were randomly allocated to one of five groups (n = 20) (0, 3, 5, 7 and 10 cmH2O of PEEP). Hemodynamic variables and respiratory parameters were measured at baseline with the patient in the supine position; at 30 min, 1, 2, 3 and 4 h during CO2 insufflation with the patient in the post-Trendelenburg position; and after deflation in the supine position with increasing PEEP.

RESULTS

The PaO2 levels and alveolar-arterial difference in oxygen tension (AaDO2) were improved in patients with PEEPs compared with patients in whom PEEP was not used. The application of PEEP (10 cmH2O) resulted in higher PaO2 levels compared to those with lower PEEP levels, but excessive peak airway pressure (PAP) was sometimes observed. The application of a PEEP of 7 cmH2O resulted in similar PaO2 levels without causing excessive PAP. There was a significant difference in central venous pressure between the groups, but there were no significant differences in heart rate, mean arterial pressure or minute ventilation between the groups.

CONCLUSIONS

A PEEP of 7 cmH2O is associated with the greater improvement of PaO2 and AaDO2 without causing excessive PAP during RLRP.

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.

Anesthetic management in patients undergoing hyperthermic chemotherapy

PURPOSE OF REVIEW

Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has become an important therapeutic option for selected patients with peritoneal surface malignancies. This aggressive multimodality treatment is complex, not only regarding surgical technique, but also regarding anesthesia. The present review represents our experience in anesthetic care.

RECENT FINDINGS

Improved prognosis compared with systemic chemotherapy alone has recently been demonstrated for cytoreductive surgery when combined with intraoperative intracavitary hyperthermic chemotherapy. Anesthetic management of HIPEC is further impacted by these developments. In addition to the ambitious, long-lasting surgery, HIPEC causes significant fluid, blood and protein losses, increased intra-abdominal pressure, systemic hyperthermia, and increased metabolic rate, leading to relevant pathophysiological alterations, and therefore represents a challenge for anesthetist and critical care physicians.

SUMMARY

Anesthetic management importantly contributes to the containment of the perioperative complications of HIPEC. An appreciation of the technical aspects and physiologic disruptions associated with intra-abdominal HIPEC is critical to ensure effective anesthetic management. Although data on this specialized surgical procedure are scarce, some referral centers have accumulated extensive experience. This article reviews the current knowledge about the anesthesiological and intensive care management of patients undergoing HIPEC. It pinpoints strategies for perioperative monitoring as well as illustrates alterations in hemodynamic, hematopoetic, and fluid hemostasis.