Effects of deep neuromuscular block with low-pressure pneumoperitoneum on respiratory mechanics and biotrauma in a steep Trendelenburg position.

We hypothesized that deep neuromuscular blockade (NMB) with low-pressure pneumoperitoneum (PP) would improve respiratory mechanics and reduce biotrauma compared to moderate NMB with high-pressure PP in a steep Trendelenburg position. Seventy-four women undergoing robotic gynecologic surgery were randomly assigned to two equal groups. Moderate NMB group was maintained with a train of four count of 1-2 and PP at 12 mmHg. Deep NMB group was maintained with a post-tetanic count of 1-2 and PP at 8 mmHg. Inflammatory cytokines were measured at baseline, at the end of PP, and 24 h after surgery. Interleukin-6 increased significantly from baseline at the end of PP and 24 h after the surgery in moderate NMB group but not in deep NMB group (Pgroup*time = 0.036). The peak inspiratory, driving, and mean airway pressures were significantly higher in moderate NMB group than in deep NMB group at 15 min and 60 min after PP (Pgroup*time = 0.002, 0.003, and 0.048, respectively). In conclusion, deep NMB with low-pressure PP significantly suppressed the increase in interleukin-6 developed after PP, by significantly improving the respiratory mechanics compared to moderate NMB with high-pressure PP during robotic surgery.

Delayed Tension Symptomatic Pneumoperitoneum After POEM Requiring Needle Decompression.

INTRODUCTION: Per-oral endoscopic myotomy (POEM) is an effective modality for the management of achalasia. Tension pneumoperitoneum is a significant complication that causes hemodynamic instability, generally within the periprocedural period. METHODS: Here, we report 2 cases of delayed tension pneumoperitoneum that was recognized and treated several hours after uncomplicated POEM. RESULTS: These cases illustrate the importance of continued vigilance for this complication outside of the immediate periprocedural period as well as the utility of computed tomography-guided aspiration in managing it. DISCUSSION: When discharging patients after POEM, caregivers should be aware of this rare complication and alert patients to return for immediate care when it happens.

High-Pressure Pneumoperitoneum Aggravates Surgery-Induced Neuroinflammation and Cognitive Dysfunction in Aged Mice.

Postoperative cognitive dysfunction (POCD) is a common complication after surgery, especially in aged patients. Neuroinflammation has been closely associated with the development of POCD. While the contribution of pneumoperitoneum to the systemic inflammation has been well documented, the effect of pneumoperitoneal pressure on neuroinflammation and postoperative cognitive function remains unclear. In this study, we showed that high-pressure pneumoperitoneum promoted the postoperative neuroinflammation and microglial activation in the hippocampus and aggravated the postoperative cognitive impairment in aged mice. These results support the requirement to implement interventions with lower intra-abdominal pressure, which allows for adequate exposure of the operative field rather than a routine pressure.

End-expiratory lung volume assessment using helium and carbon dioxide in an experimental model of pediatric capnoperitoneum.

BACKGROUND: Capnoperitoneum during laparoscopy leads to cranial shift of the diaphragm, loss in lung volume, and risk of impaired gas exchange. Infants are susceptible to these changes and bedside assessment of lung volume during laparoscopy might assist with optimizing the ventilation. Thus, the primary aim was to investigate the monitoring value of a continuous end-expiratory lung volume (EELV) assessment method based on CO2 dynamics ( EELV CO 2 ) in a pediatric capnoperitoneum model by evaluating the correlation and trending ability against helium washout (EELVHe ). METHODS: Intra-abdominal pressure (IAP) was randomly varied between 0, 6, and 12 mm Hg with CO2 insufflation, while positive end-expiratory pressure (PEEP) levels of 3, 6, and 9 cm H2 O were randomly applied in eight anesthetized and mechanically ventilated chinchilla rabbits. Concomitant EELV CO 2 and EELVHe and lung clearance index (LCI) were obtained under each experimental condition. RESULTS: Significant correlations were found between EELV CO 2 and EELVHe before capnoperitoneum (r = .85, P < .001), although increased IAP distorted this relationship. The negative influence of IAP was counteracted by the application of PEEP 9, which restored the correlation between EELV CO 2 and EELVHe and resulted in 100% concordance rate between the methods regarding changes in lung volume. EELVHe and LCI showed a curvilinear relationship, and an EELVHe of approximately 20 mL kg-1 , determined with a receiver operating characteristic curve, was associated with near-normal LCI values. CONCLUSION: In this animal model of pediatric capnoperitoneum, reliable assessment of changes in EELV based on EELV CO 2 requires an open lung strategy, defined as EELV above approximately 20 mL kg-1 .

Intraabdominal Pressure Targeted Positive End-expiratory Pressure during Laparoscopic Surgery: An Open-label, Nonrandomized, Crossover, Clinical Trial.

BACKGROUND: Pneumoperitoneum for laparoscopic surgery is associated with a rise of driving pressure. The authors aimed to assess the effects of positive end-expiratory pressure (PEEP) on driving pressure at varying intraabdominal pressure levels. It was hypothesized that PEEP attenuates pneumoperitoneum-related rises in driving pressure. METHODS: Open-label, nonrandomized, crossover, clinical trial in patients undergoing laparoscopic cholecystectomy. "Targeted PEEP" (2 cm H2O above intraabdominal pressure) was compared with "standard PEEP" (5 cm H2O), with respect to the transpulmonary and respiratory system driving pressure at three predefined intraabdominal pressure levels, and each patient was ventilated with two levels of PEEP at the three intraabdominal pressure levels in the same sequence. The primary outcome was the difference in transpulmonary driving pressure between targeted PEEP and standard PEEP at the three levels of intraabdominal pressure. RESULTS: Thirty patients were included and analyzed. Targeted PEEP was 10, 14, and 17 cm H2O at intraabdominal pressure of 8, 12, and 15 mmHg, respectively. Compared to standard PEEP, targeted PEEP resulted in lower median transpulmonary driving pressure at intraabdominal pressure of 8 mmHg (7 [5 to 8] vs. 9 [7 to 11] cm H2O; P = 0.010; difference 2 [95% CI 0.5 to 4 cm H2O]); 12 mmHg (7 [4 to 9] vs.10 [7 to 12] cm H2O; P = 0.002; difference 3 [1 to 5] cm H2O); and 15 mmHg (7 [6 to 9] vs.12 [8 to 15] cm H2O; P < 0.001; difference 4 [2 to 6] cm H2O). The effects of targeted PEEP compared to standard PEEP on respiratory system driving pressure were comparable to the effects on transpulmonary driving pressure, though respiratory system driving pressure was higher than transpulmonary driving pressure at all intraabdominal pressure levels. CONCLUSIONS: Transpulmonary driving pressure rises with an increase in intraabdominal pressure, an effect that can be counterbalanced by targeted PEEP. Future studies have to elucidate which combination of PEEP and intraabdominal pressure is best in term of clinical outcomes.

Impact of pneumoperitoneum on intra-abdominal microcirculation blood flow: an experimental randomized controlled study of two insufflator models during transanal total mesorectal excision : An experimental randomized multi-arm trial with parallel treatment design.

OBJECTIVE: To compare changes in microcirculation blood flow (MCBF) between pulsatile and continuous flow insufflation. Transanal total mesorectal excision (TaTME) was developed to improve the quality of the resection in rectal cancer surgery. The AirSeal IFS® insufflator facilitates the pelvic dissection, although evidence on the effects that continuous flow insufflation has on MCBF is scarce. METHODS: Thirty-two pigs were randomly assigned to undergo a two-team TaTME procedure with continuous (n = 16) or pulsatile insufflation (n = 16). Each group was stratified according to two different pressure levels in both the abdominal and the transanal fields, 10 mmHg or 14 mmHg. A generalized estimating equations (GEE) model was used. RESULTS: At an intra-abdominal pressure (IAP) of 10 mmHg, continuous insufflation was associated with a significantly lower MCBF reduction in colon mucosa [13% (IQR 11;14) vs. 21% (IQR 17;24) at 60 min], colon serosa [14% (IQR 9.2;18) vs. 25% (IQR 22;30) at 60 min], jejunal mucosa [13% (IQR 11;14) vs. 20% (IQR 20;22) at 60 min], renal cortex [18% (IQR 15;20) vs. 26% (IQR 26;29) at 60 min], and renal medulla [15% (IQR 11;20) vs. 20% (IQR 19;21) at 90 min]. At an IAP of 14 mmHg, MCBF in colon mucosa decreased 23% (IQR 14;27) in the continuous group and 28% (IQR 26;31) in the pulsatile group (p = 0.034). CONCLUSION: TaTME using continuous flow insufflation was associated with a lower MCBF reduction in colon mucosa and serosa, jejunal mucosa, renal cortex, and renal medulla compared to pulsatile insufflation.

Effects of low- and high-pressure carbon dioxide pneumoperitoneum on intracranial pressure during laparoscopic cholecystectomy.

BACKGROUND: Laparoscopic surgeries are a risk factor for raised intracranial **pressure and neurological complications. Even though rare, the consequences may be severe. METHODS: One hundred and one patients of laparoscopic cholecystectomy were enrolled and were randomized into two groups: low-pressure 8 mm Hg (Group A) and high-pressure 14 mm Hg (Group B) carbon dioxide pneumoperitoneum during surgery. Fifty patients were in group A and 51 patients were in group B. Intracranial pressure was measured by measuring the optic nerve sheath diameter (ONSD) using ultrasound examination. Baseline ONSD was recorded followed by ONSD recording at various intervals: at the induction of anesthesia; 30 min, 45 min, at the end of surgery; and 30 min post surgery. RESULTS: The groups were comparable in terms of demographics and comorbidities. The mean age of group A was 45 years and for group B it was 45.75 years. Most common indication for surgery was symptomatic gall stone disease. Baseline ONSD in group A was 0.427 ± 0.0459 mm, whereas it was 0.412 ± 0.0412 mm in group B. There was a significant rise of ONSD (p < 0.05) 30 min after induction of pneumoperitoneum and up to 30 min post anesthesia. In the low-pressure group 7 (14%) patients had a significant rise of ICP, whereas in the high-pressure group 20 (39%) patients had a significant rise of ICP (p < 0.05). CONCLUSIONS: High-pressure pneumoperitoneum causes significant rise in intracranial pressure in comparison to low-pressure pneumoperitoneum during laparoscopic cholecystectomy, which can be monitored by ONSD measurement by ultrasound examination and is totally non-invasive.

Airway Closure during Surgical Pneumoperitoneum in Obese Patients.

BACKGROUND: Airway closure causes lack of communication between proximal airways and alveoli, making tidal inflation start only after a critical airway opening pressure is overcome. The authors conducted a matched cohort study to report the existence of this phenomenon among obese patients undergoing general anesthesia. METHODS: Within the procedures of a clinical trial during gynecological surgery, obese patients underwent respiratory/lung mechanics and lung volume assessment both before and after pneumoperitoneum, in the supine and Trendelenburg positions, respectively. Among patients included in this study, those exhibiting airway closure were compared to a control group of subjects enrolled in the same trial and matched in 1:1 ratio according to body mass index. RESULTS: Eleven of 50 patients (22%) showed airway closure after intubation, with a median (interquartile range) airway opening pressure of 9 cm H2O (6 to 12). With pneumoperitoneum, airway opening pressure increased up to 21 cm H2O (19 to 28) and end-expiratory lung volume remained unchanged (1,294 ml [1,154 to 1,363] vs. 1,160 ml [1,118 to 1,256], P = 0.155), because end-expiratory alveolar pressure increased consistently with airway opening pressure and counterbalanced pneumoperitoneum-induced increases in end-expiratory esophageal pressure (16 cm H2O [15 to 19] vs. 27 cm H2O [23 to 30], P = 0.005). Conversely, matched control subjects experienced a statistically significant greater reduction in end-expiratory lung volume due to pneumoperitoneum (1,113 ml [1,040 to 1,577] vs. 1,000 ml [821 to 1,061], P = 0.006). With airway closure, static/dynamic mechanics failed to measure actual lung/respiratory mechanics. When patients with airway closure underwent pressure-controlled ventilation, no tidal volume was inflated until inspiratory pressure overcame airway opening pressure. CONCLUSIONS: In obese patients, complete airway closure is frequent during anesthesia and is worsened by Trendelenburg pneumoperitoneum, which increases airway opening pressure and alveolar pressure: besides preventing alveolar derecruitment, this yields misinterpretation of respiratory mechanics and generates a pressure threshold to inflate the lung that can reach high values, spreading concerns on the safety of pressure-controlled modes in this setting.

Effects of long periods of pneumoperitoneum combined with the head-up position on heart rate-corrected QT interval during robotic gastrectomy: an observational study.

OBJECTIVE: Pneumoperitoneum and the head-up position reportedly stimulate the sympathetic nervous system, potentially increasing the risk of cardiac arrhythmia. We evaluated the effects of a long duration of pneumoperitoneum in the head-up position on the heart rate-corrected QT (QTc) interval during robotic gastrectomy. METHODS: This prospective observational study involved 28 patients undergoing robotic gastrectomy. The QTc interval was recorded at the following time points: before anaesthetic induction (baseline); 10 minutes after tracheal intubation; 1, 5, 30, 60, and 90 minutes after pneumoperitoneum induction in the head-up position; after pneumoperitoneum desufflation in the supine position; and at the end of surgery. The primary outcome was the QTc interval, which was measured 90 minutes after pneumoperitoneum combined with the head-up position. RESULTS: Compared with baseline, the QTc interval was significantly prolonged at 1 and 60 minutes after pneumoperitoneum, peaked at 90 minutes, and was sustained and notably prolonged until the end of surgery. However, no considerable haemodynamic changes developed. CONCLUSION: A long period of carbon dioxide pneumoperitoneum application in a head-up position significantly prolonged the QTc interval during robotic gastrectomy. Therefore, diligent care and close monitoring are required for patients who are susceptible to developing ventricular arrhythmia. Trial Registration: Registered at ClinicalTrials.gov; https://clinicaltrials.gov/ct2/show/NCT02604979 ; Registration number NCT02604979.

Predictive values of pulse pressure variation and stroke volume variation for fluid responsiveness in patients with pneumoperitoneum.

Animal studies suggest that dynamic predictors remain useful in patients with pneumoperitoneum, but human data is conflicting. Our aim was to determine predictive values of pulse pressure variation (PPV) and stroke volume variation (SVV) in patients with pneumoperitoneum using LiDCORapid™ haemodynamic monitor. Standardised fluid challenges of colloid were administered to patients undergoing laparoscopic procedures, one fluid challenge per patient. Intra-abdominal pressure was automatically held at 12 mmHg. Fluid responsiveness was defined as an increase in nominal stroke index (nSI) ≥ 10%. Linear regression was used to assess the ability of PPV and SVV to track the changes of nSI and logistic regression and area under the receiver operating curve (AUROC) to assess the predictive value of PPV and SVV for fluid responsiveness. Threshold values for PPV and SVV were obtained using the "gray zone" approach. A p < 0.05 was considered as statistically significant. 56 patients were included in analysis. 41 patients (73%) responded to fluids. Both PPV and SVV tracked changes in nSI (Spearman correlation coefficients 0.34 for PPV and 0.53 for SVV). Odds ratio for fluid responsiveness for PPV was 1.163 (95% CI 1.01-1.34) and for SVV 1.341 (95% CI 1.10-1.63). PPV achieved an AUROC of 0.674 (95% CI 0.518-0.830) and SVV 0.80 (95% CI 0.668-0.932). The gray zone of PPV ranged between 6.5 and 20.5% and that of SVV between 7.5 and 13%. During pneumoperitoneum, as measured by LiDCORapid™, PPV and SVV can predict fluid responsiveness, however their sensitivity is lower than the one reported in conditions without pneumoperitoneum. Trial registry number: (with the Australian New Zealand Clinical Trials Registry): ACTRN12612000456853.

A rare case of simultaneous pneumoperitoneum and pneumomediastinum with a review of the literature.

Simultaneous pneumoperitoneum and pneumomediastinum is a rare clinical occurrence. It has been reported in the literature as a complication of various medical and dental procedures. To our knowledge, we present the first case of a non-iatrogenic and traumatic simultaneous pneumoperitoneum and pneumomediastinum in a previously independent 91-year-old man who presented to hospital with back and chest wall pain following mechanical fall from standing. A new radiological diagnosis of diverticular disease with possible perforation was made following admission. Despite appropriate management and supportive measures, the patient died 12 days after admission from a kidney injury.

Air and its Sonographic Appearance: Understanding the Artifacts.

BACKGROUND: Although air has traditionally been considered a barrier to sonographic imaging, when encountered in unusual settings it can serve as an important indicator of various pathologic states as well. Clinician recognition and thorough understanding of the characteristic pattern of artifacts generated by air are critical for making a number of important diagnoses. CASE SERIES: We present five emergency department cases in which air was visualized in a pathologic location. Pneumothorax, pneumoperitoneum, necrotizing fasciitis, or Fournier's gangrene, and subcutaneous emphysema and pneumomediastinum, can be rapidly and easily identified on ultrasound by the presence of air artifacts. The relevant sonographic findings are described and discussed in this article. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Due to its inherent impedance mismatch with other human tissues, air has a characteristic appearance on ultrasound that includes irregular hyperechoic structures, "dirty shadowing," A-lines, and decreased visualization of deeper structures. Knowledge of the sonographic appearance of air artifacts can assist the physician in making a diagnosis, selecting appropriate additional imaging, and enlisting specialist consultation.

The impact of a pulmonary recruitment maneuver to reduce post-laparoscopic shoulder pain: A randomized controlled trial.

OBJECTIVE: A pulmonary recruitment maneuver (PRM) can effectively reduce post-laparoscopic shoulder pain (PLSP). However, a high-pressure PRM may cause pulmonary barotrauma. This study aimed to evaluate the efficacy and safety of a PRM using two different maximum inspiratory pressures (40 and 60cmH2O) for reducing PLSP. STUDY DESIGN: Patients undergoing gynecologic laparoscopy were randomly allocated to a control group (n=30), a 40 cmH2O PRM group (n=30), and a 60 cmH2O PRM group (n=30). In the control group, residual carbon dioxide was removed by passive exsufflation through the port site. In the two intervention groups, the PRM consisting of five manual pulmonary inflations was performed at the end of surgery with a maximum pressure of 40 cmH2O or 60 cmH2O, respectively. Shoulder pain and wound pain were recorded using a visual analogue scale at 24 and 48h postoperatively. RESULTS: Wound pain scores at 24 and 48h post-surgery were not different between the three groups. The PLSP scores in the two intervention groups were significantly lower than that seen in the control group at 24 and 48h postoperatively (P=0.006 and P<0.001, respectively). However, there were no statistically significant differences in the PLSP scores between the two intervention groups. CONCLUSION: A low-pressure PRM (40cmH2O) is as effective as a high-pressure PRM (60cmH2O) for removing residual gas from the peritoneal cavity. PRM using a maximal inspiratory pressure of 40cmH2O is safe and efficacious for the reduction of PLSP.

Evidence for the absence of visceral pain in C57BL6/N mice subjected to therapeutically relevant O3/O2-pneumoperitoneum.

Each different gas that is used to induce a pneumoperitoneum (PP) exhibits individual effects within the peritoneal cavity. This might include adverse effects such as pain and/or inflammatory reactions. The acute effects of ozonized oxygen (O3/O2), a highly oxidative gas mixture, after being insufflated into the peritoneal cavity are analysed in this study. Using the abdominal constriction response ('writhing') assay of chemical nociception in C57BL6/N mice, O3/O2-PP was found not to be associated with visible pain responses and did not alter the c-fos expression in the spinal cord. In addition, mRNA expression levels of the pro-inflammatory cytokines, interleukin (IL)-1ß and IL-6, were found unaltered in the spleen 2 h after insufflation. In conclusion, O3/O2-PP is free of adverse pain and does not trigger inflammatory immune responses.

Effects of pneumoperitoneum and Trendelenburg position on intracranial pressure assessed using different non-invasive methods.

BACKGROUND: The laparoscopic approach is becoming increasingly frequent for many different surgical procedures. However, the combination of pneumoperitoneum and Trendelenburg positioning associated with this approach may increase the patient's risk for elevated intracranial pressure (ICP). Given that the gold standard for the measurement of ICP is invasive, little is known about the effect of these common procedures on ICP. METHODS: We prospectively studied 40 patients without any history of cerebral disease who were undergoing laparoscopic procedures. Three different methods were used for non-invasive estimation of ICP: ultrasonography of the optic nerve sheath diameter (ONSD); transcranial Doppler-based (TCD) pulsatility index (ICPPI); and a method based on the diastolic component of the TCD cerebral blood flow velocity (ICPFVd). The ONSD and TCD were measured immediately after induction of general anaesthesia, after pneumoperitoneum insufflation, after Trendelenburg positioning, and again at the end of the procedure. RESULTS: The ONSD, ICPFVd, and ICPPI increased significantly after the combination of pneumoperitoneum insufflation and Trendelenburg positioning. The ICPFVd showed an area under the curve of 0.80 [95% confidence interval (CI) 0.70-0.90] to distinguish the stage associated with the application of pneumoperitoneum and Trendelenburg position; ONSD and ICPPI showed an area under the curve of 0.75 (95% CI 0.65-0.86) and 0.70 (95% CI 0.58-0.81), respectively. CONCLUSIONS: The concomitance of pneumoperitoneum and the Trendelenburg position can increase ICP as estimated with non-invasive methods. In high-risk patients undergoing laparoscopic procedures, non-invasive ICP monitoring through a combination of ONSD ultrasonography and TCD-derived ICPFVd could be a valid option to assess the risk of increased ICP.

[Blunt chest trauma with pneumomediastinum and pneumoperitoneum secondary to Macklin effect. Case report]. / Trauma contuso de tórax con neumomediastino y neumoperitoneo secundario a efecto Macklin. Reporte de un caso.

BACKGROUND: Pneumomediastinum is the presence of free air around mediastinal structures, which may be spontaneous or secondary, and can occur in 10% of patients with blunt chest trauma, with the Macklin effect being its main pathophysiology. CLINICAL CASE: A 21 year old male, hit by motor vehicle, with alvéolopalatal fracture and blunt chest trauma, who, 72 hrs after admission, shows subcutaneous emphysema in the anterior chest. A simple tomography of the chest and abdomen was performed, finding a pneumomediastinum, bilateral pulmonary contusions and pneumoperitoneum. Oesophageal, tracheobronchial or intra-abdominal viscera injuries were ruled out, establishing the cause of pneumomediastinum and pneumoperitoneum due to the Macklin effect. This required conservative management in intensive care unit, with a favourable clinical course and discharged after a 10 day hospital stay. DISCUSSION: Macklin effect is caused by dissection of air medially along the bronchoalveolar sheath (interstitial emphysema), secondary to alveolar breakdown and extending into mediastinal and other anatomical structures (pneumoperitoneum). It has been documented in blunt trauma, as well as in acute asthma, positive pressure ventilation, or after Valsalva manoeuvres. The imaging method of choice is computed tomography, and its characteristic findings, interstitial emphysema adhering to a bronchus and pulmonary blood vessel. CONCLUSIONS: In the presence of pneumomediastinum and pneumoperitoneum is necessary to rule out oesophageal and tracheobronchial injury before establishing the Macklin effect as its cause. The diagnosis is made with computed tomography and managed conservatively.

Intraoperative non invasive intracranial pressure monitoring during pneumoperitoneum: a case report and a review of the published cases and case report series.

Non-invasive measurement of ICP (nICP) can be warranted in patients at risk for developing increased ICP during pneumoperitoneum (PP). Our aim was to assess available data on the application of nICP monitoring during these procedures and to present a patient assessed with an innovative combination of noninvasive tools. Literature review of nICP assessment during PP did not find any studies comparing different methods intraprocedurally and only few studies of any nICP monitoring were available: transcranial Doppler (TCD) studies used the pulsatility index (PI) as an estimator of ICP and failed to detect a significant ICP increase during PP, whereas two out of three optic nerve sheath diameter (ONSD) studies detected a statistically significant ICP increase. In the case study, we describe a 52 year old man with a high grade thalamic glioma who underwent urgent laparoscopic cholecystectomy. Considering the high intraoperative risk of developing intracranial hypertension, he was monitored through parallel ONSD ultrasound measurement and TCD derived formulae (flow velocity diastolic formula, FVdnICP, and PI). ONSD and FVdnICP methods indicated a significant ICP increase during PP, whereas PI was not significantly increased. Our experience, combined with the literature review, seems to suggest that PI might not detect ICP changes in this context, however we indicate a possible interest of nICP monitoring during PP by means of ONSD and of TCD derived FVdNICP, especially for patients at risk for increased ICP.

Intra-abdominal pressure, Cardiac Index and vascular resistance during hyperthermic intraperitoneal chemotherapy: a prospective observational study.

BACKGROUND: Increased intra-abdominal pressure and hemodynamic variations during hyperthermic intraperitoneal chemotherapy (HIPEC) are expected to be comparable to pneumoperitoneum with decreased Cardiac Index (CI) and increased Systemic Vascular Resistance Index (SVRI). We hypothesized that despite comparable increased intra-abdominal pressure, hemodynamic changes during HIPEC would substantially differ from those described in laparoscopic surgery. METHODS: In this prospective observational clinical study, after obtaining written informed consent, we assessed intra-abdominal pressure and hemodynamic and respiratory changes during HIPEC in 10 consecutive patients. Intra-abdominal pressure as the primary endpoint was continuously measured with a catheter placed in the abdominal cavity. Secondary endpoints were hemodynamic changes measured by pulse contour analysis and respiratory alterations. Fluid management was based on stroke volume variation. RESULTS: The mean intra-abdominal pressure was constantly elevated during HIPEC at a level of 14.2 mmHg (P=0.002 compared to baseline). The mean SVRI dropped from 1716 dyn*sec/cm³/m² to 1490 dyn*sec/cm5/m² at the end of HIPEC (P<0.05). Mean CI increased from 3.2 to 3.45 L/m² (P<0.001) and Horovitz index decreased from 548 to 380 (P=0.001). Median fluid intake was 7000 mL. No patient developed acute kidney injury. CONCLUSIONS: Increased intra-abdominal pressure during HIPEC was comparable to pneumoperitoneum. Hemodynamic changes however were opposed with a decrease in SVRI and a compensative increase in CI. Current guidelines for anesthetic management in patients undergoing HIPEC are mainly based on findings from laparoscopic surgery and should therefore be reconsidered critically.