The physiologic effects of pneumoperitoneum in the morbidly obese

Hysterectomy in obese patients: special considerations

A literature search was performed to find evidence-based practices that aid in the preoperative evaluation, intraoperative techniques, and postoperative management of the obese patient requiring hysterectomy. Complications are more frequent than in normal weight patients and are more difficult to manage. Few studies provide direct evidence with which to help guide surgical decision-making and postoperative management. However, there is sufficient evidence to support that when feasible, the vaginal route is preferable in obese patients. Techniques validated for normal weight patients like antibiotic and thromboembolism prophylaxis seem effective in obese patients, and are likely even more important.

Changes in endotracheal tube cuff pressure during laparoscopic surgery in head-up or head-down position

BACKGROUND

The abdominal insufflation and surgical positioning in the laparoscopic surgery have been reported to result in an increase of airway pressure. However, associated effects on changes of endotracheal tube cuff pressure are not well established.

METHODS

70 patients undergoing elective laparoscopic colorectal tumor resection (head-down position, n = 38) and laparoscopic cholecystecomy (head-up position, n = 32) were enrolled and were compared to 15 patients undergoing elective open abdominal surgery. Changes of cuff and airway pressures before and after abdominal insufflation in supine position and after head-down or head-up positioning were analysed and compared.

RESULTS

There was no significant cuff and airway pressure changes during the first fifteen minutes in open abdominal surgery. After insufflation, the cuff pressure increased from 26 ± 3 to 32 ± 6 and 27 ± 3 to 33 ± 5 cmH2O in patients receiving laparoscopic cholecystecomy and laparoscopic colorectal tumor resection respectively (both p < 0.001). The head-down tilt further increased cuff pressure from 33 ± 5 to 35 ± 5 cmH2O (p < 0.001). There six patients undergoing colorectal tumor resection (18.8%) and eight patients undergoing cholecystecomy (21.1%) had a total increase of cuff pressure more than 10 cm H2O (18.8%). There was no significant correlation between increase of cuff pressure and either the patient's body mass index or the common range of intra-abdominal pressure (10-15 mmHg) used in laparoscopic surgery.

CONCLUSIONS

An increase of endotracheal tube cuff pressure may occur during laparoscopic surgery especially in the head-down position.

Morbid obesity and optimization of preoperative fluid therapy

BACKGROUND

Preoperative venous return (VR) optimization and adequate blood volume is essential in management of morbidly obese patients (MO) in order to avoid perioperative circulatory instability. In this study, all subjects underwent a preoperative 3-week preparation by rapid-weight-loss-diet (RWL) as part of their treatment program for bariatric surgery.

METHODS

This is a prospective, observational study of 34 morbidly obese patients consecutively scheduled for bariatric surgery at Sunderby County Hospital, Luleå, Sweden. Preoperative transthoracic echocardiography (TTE) was performed in the awake state before and after intravascular volume challenge (VC) of 6 ml colloids/kg ideal body weight (IBW). Effects of standardized VC were evaluated by TTE. Dynamic and non-dynamic echocardiographic indices for VC were studied. Volume responsiveness and level of VR before and after VC were assessed by TTE. An increase of stroke volume ≥13% was considered as a volume responder.

RESULTS

Twenty-nine out of 34 patients were volume responders. After VC, a majority of patients (23/34) were euvolemic, and only 2/34 were hypovolemic. Post-VC hypervolemia was observed in 9/34 of patients.

CONCLUSIONS

The IBW-based volume challenge regime was found to be suitable for preoperative rehydration of RWL-prepared MO. Most of the patients were volume responders. Preoperative state of VR was not associated with volume responsiveness. IBW estimates and appropriate monitoring avoids potential hyperhydration in MO. For VC assessment, conventional Doppler indices were found to be more suitable compared to tissue Doppler, giving sufficient information on pressure-volume correlation of the left ventricle in morbidly obese.

Comparison of a standard CO₂ pressure pneumoperitoneum insufflator versus AirSeal: study protocol of a randomized controlled trial

Background

AirSeal™ is a novel class of valve-free insufflation system that enables a stable pneumoperitoneum with continuous smoke evacuation and carbon dioxide (CO₂) recirculation during laparoscopic surgery. Comparison data to standard CO₂ pressure pneumoperitoneum insufflators is scarce. The aim of this study is to evaluate the potential advantages of AirSeal™ compared to a standard CO₂ insufflator.

Methods/Design

This is a single center randomized controlled trial comparing elective laparoscopic cholecystectomy, colorectal surgery and hernia repair with AirSeal™ (group A) versus a standard CO₂ pressure insufflator (group S). Patients are randomized using a web-based central randomization and registration system. Primary outcome measures will be operative time and level of postoperative shoulder pain by using the visual analog score (VAS). Secondary outcomes include the evaluation of immunological values through blood tests, anesthesiological parameters, surgical side effects and length of hospital stay. Taking into account an expected dropout rate of 5%, the total number of patients is 182 (n = 91 per group). All tests will be two-sided with a confidence level of 95% (P <0.05).

Discussion

The duration of an operation is an important factor in reducing the patient’s exposure to CO₂ pneumoperitoneum and its adverse consequences. This trial will help to evaluate if the announced advantages of AirSeal™, such as clear sight of the operative site and an exceptionally stable working environment, will facilitate the course of selected procedures and influence operation time and patients clinical outcome.

Trial registration

ClinicalTrials.gov NCT01740011, registered 23 November 2012.

Clinical significance of elevated intraabdominal pressure during common conditions and procedures

INTRODUCTION

Pregnancy, obesity, peritoneal dialysis, pneumoperitoneum, prone position and application of positive end-expiratory pressure are associated with elevated intraabdominal pressure (IAP).

OBJECTIVE

To review the relation between these conditions and procedures, and intraabdominal hypertension (IAH) or abdominal compartment syndrome (ACS).

METHODS

Search of PubMed and Google Scholar and review of article bibliographies.

RESULTS AND CONCLUSION

Only obesity, peritoneal dialysis, and pneumoperitoneum are associated with symptoms related to IAH and these symptoms are reversible.

The use of VivaSight™ single lumen endotracheal tube in morbidly obese patients undergoing laparoscopic sleeve gastrectomy

Background

The population of obese patients is progressively growing and bariatric operations are becoming increasingly common. Morbidly obese patients require special anesthetic care and are often considered to be difficult to ventilate and intubate. The VivaSight™ Single Lumen tube is an endotracheal tube with a camera embedded in its tip. The view from the tip appears continuously on a monitor in the anesthesiologist's vicinity. The aim of this study was to assess the VivaSight™ in comparison with conventional endotracheal tube as an aid in the intubation and surveillance of tube position during surgery of obese patients.

Methods

This is a prospective study of 72 adult obese patients who underwent laparoscopic sleeve gastrectomy. The patients were randomly assigned to be intubated by either the VivaSight™ (40 patients, test group) or a conventional endotracheal tube (32 patients, control group). Data on the patients, the pre-operative airway evaluation, the endotracheal intubation and the post-operative outcome were collected and compared.

Results

The Mallampati scores were significantly higher in the test group than in the control group. Endotracheal intubation took 29 ± 10 and 24 ± 8 seconds using the VivaSight™ and a conventional tube respectively (p = 0.02). Three of the patients in the control group, while none of those in the test group, had soft tissue injury (p < 0.05).

Conclusion

We found the VivaSight™ SL to be helpful in the endotracheal intubation and continuous surveillance of tube position in morbidly obese patients undergoing laparoscopic sleeve gastrectomy.

Cytoreduction with hyperthermic intraperitoneal chemotherapy: An anaesthetic challenge

Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy plays a considerable role as a treatment modality in surgical oncology in western countries. The advantage of this procedure is that the heated chemotherapeutic agent is circulated in the abdominal cavity and achieves high peritoneal concentration with limited systemic absorption. This procedure is complex not only to the surgical team, but also to the anaesthetist because apart from managing the usual physiologic changes associated with major surgery, one should also be prepared to manage the physiologic changes during the hyperthermic phase. Here, we present our experience with our first case.

The influence of laparoscopic vs. open gastric bypass on hemodynamic function in morbidly obese patients during general anesthesia

INTRODUCTION

The open or laparoscopic procedure has an important influence on the hemodynamic function in morbidly obese patients undergoing bariatric surgery. The anesthesiologist and surgeon must be aware of changes in hemodynamic performance during laparoscopy or laparotomy under general anesthesia.

AIM

TO EVALUATE AND COMPARE THE HEMODYNAMICS IN TWO TYPES OF SURGERY: open vs. laparoscopic.

MATERIAL AND METHODS

After obtaining the local ethics committee approval 60 morbidly obese (MO) patients (body mass index ≥ 40 kg/m(2)) scheduled for elective open or laparoscopic Roux-en-Y gastric bypass were included. Patients were allocated to study groups depending on the scheduled type of surgery (no randomization). General anesthesia with sevoflurane was performed. The hemodynamic parameters were recorded using a HemoSonic 100 device - a transesophageal Doppler measurement at time points: T1 - initial, T2 - after creating pneumoperitoneum (group PP) or opening the abdomen (group OP).

RESULTS

Complete data were collected on 28 patients in group LP and 21 in group OP. There was no statistical difference between groups in demographic data. At time point T2 in both groups the parameters stroke volume, peak velocity and cardiac index decreased, and total systemic vascular resistance increased significantly compared to T1 (p < 0.05). In group LP the parameters cardiac output and acceleration (Acc) of blood decreased significantly compared to T1 (p < 0.05). There were significant differences between groups (p > 0.05) in cardiac output, total systemic vascular resistance and Acc, which were significantly higher in the OP group. In both groups mean arterial pressure increased and heart rate stayed similar to T1 with no significant difference (p > 0.05). No complications were observed.

CONCLUSIONS

Pneumoperitoneum has a significant negative influence on hemodynamic function during laparoscopic bariatric procedures compared to open surgery in morbidly obese patients.

Laparoscopic colorectal surgery in patients with impaired renal function: impact on postoperative renal function compared with open surgery

BACKGROUND

Laparoscopic surgery has been associated with a perioperative decrease in renal function. As a result, an open approach may be preferred in patients with impaired renal function when prolonged laparoscopic procedures are anticipated. The aim of this study was to examine changes in renal function following colorectal operations and compare between the open and the laparoscopic approaches, in patients with preoperative impaired renal function.

PATIENTS AND METHODS

This is a single-center retrospective study. Records of all patients with impaired renal function (estimated glomerular filtration rate [eGFR] <60 mL/minute) who underwent elective colorectal resection between 2007 and 2011 were reviewed. The changes in eGFR were examined and compared between open and laparoscopic procedures.

RESULTS

Ninety consecutive patients with impaired renal function who underwent elective colorectal surgery from 2007 to 2011 were identified. Forty-seven patients underwent laparoscopic surgery, and 43 had an open surgery; 23.2% of the patients who had open surgery and 21.7% of the patients who underwent a laparoscopic procedure demonstrated a decrease in eGFR at the time of discharge (P=not significant). The mean decrease in eGFR did not differ between the two groups (6.3 ± 6.8 mL/minute versus 4.04 ± 4.01 mL/minute; P=.34). None of the patients required dialysis. Postoperative complications were found to be a risk factor for a significant decrease in renal function.

CONCLUSIONS

Renal function may deteriorate in patients with chronic kidney disease who undergo elective colorectal surgery. No difference was noted in the incidence or severity of such deterioration between open and laparoscopic approaches. Postoperative complications are associated with deterioration in renal function regardless of the operative approach.

Alveolar recruitment maneuver and perioperative ventilatory support in obese patients undergoing abdominal surgery

The development of abdominal surgery represents an alternative therapy for the morbidly obese; however, patients undergoing this surgical procedure often experience postoperative pulmonary complications. The use of alveolar recruitment maneuvers and/or perioperative ventilatory strategies is a possible alternative to reduce these complications, focusing on the reduction of postoperative pulmonary complications. In this review, the benefits of perioperative ventilatory strategies and the implementation of alveolar recruitment maneuvers in obese patients undergoing abdominal surgery are described.

A prospective randomized study of systemic inflammation and immune response after laparoscopic nissen fundoplication performed with standard and low-pressure pneumoperitoneum

BACKGROUND

The aim of this study was to compare changes in the systemic inflammation and immune response in the early postoperative (p.o.) period after laparoscopic Nissen fundoplication (LNF) was performed with standard-pressure and low-pressure carbon dioxide pneumoperitoneum.

MATERIALS AND METHODS

We studied 68 patients with documented gastroesophageal reflux disease and who underwent a LNF: 35 using standard-pressure (12 to 14 mmHg) and 33 low-pressure (6 to 8 mmHg) pneumoperitoneum. White blood cells, peripheral lymphocytes subpopulation, human leukocyte antigen-DR, neutrophil elastase, interleukin (IL)-6 and IL-1, and C-reactive protein were investigated.

RESULTS

A significantly higher concentration of neutrophil elastase, IL-6 and IL-1, and C-reactive protein was detected postoperatively in the standard-pressure group of patients in comparison with the low-pressure group (P<0.05). A statistically significant change in human leukocyte antigen-DR expression was recorded p.o. at 24 hours, as a reduction of this antigen expressed on monocyte surface in patients from standard group; no changes were noted in low-pressure group patients (P<0.05).

CONCLUSIONS

This study demonstrated that reducing the pressure of the pneumoperitoneum to 6 to 8 mm Hg during LNF is reduced p.o. inflammatory response and avoided p.o. immunosuppression.

Incidence of postoperative venous thromboembolism after laparoscopic versus open colorectal cancer surgery: a meta-analysis

The objective of this study was to systematically compare the incidence of postoperative venous thromboembolism (VTE; deep vein thrombosis and/or pulmonary embolism) in patients with colorectal cancer after laparoscopic surgery and conventional open surgery. A systematic search of Medline, EMBASE, and the Cochrane Central Register of Controlled Trials was conducted. Eleven randomized control trials involving 3058 individuals who reported VTE outcomes were identified, of whom 1677 were treated with laparoscopic therapy and 1381 underwent open surgery. The combined results of the individual trials showed no statistically significant difference in the odds ratio for overall VTE (odds ratio 0.64, 95% confidence interval, 0.33-1.23, P=0.18), as well as in subgroups of deep vein thrombosis and anticoagulant prophylaxis between these 2 approaches. In conclusion, laparoscopic resection could achieve similar outcomes in terms of the incidence of VTE, which are associated with long-term benefits of the patients.

Rapid weight loss is associated with preoperative hypovolemia in morbidly obese patients

BACKGROUND

In morbidly obese patients (MO), adequate levels of venous return (VR) and left ventricular filling pressures (LVFP) are crucial in order to augment perioperative safety. Rapid weight loss (RWL) preparation with very low calorie diet is commonly used aiming to facilitate bariatric surgery. However, the impact of RWL on VR and LVFP is poorly studied.

METHODS

In this prospective, controlled, single-center study, we hypothesized that RWL-prepared MO prior to bariatric surgery can be hypovolemic (i.e., low VR) and compared MO to lean controls with conventional overnight fasting. Twenty-eight morbidly obese patients were scheduled consecutively for bariatric surgery and 19 lean individuals (control group, CG) for elective general surgery. Preoperative assessment of VR, LVFP, and biventricular heart function was performed by a transthoracic echocardiography (TTE) protocol to all patients in the awake state. Assessment of VR and LVFP was made by inferior vena cava maximal diameter (IVCmax) and inferior vena cava collapsibility index- (IVCCI) derived right atrial pressure estimations.

RESULTS

A majority of MO (71.4 %) were hypovolemic vs. 15.8 % of lean controls (p < 0.001, odds ratio = 13.3). IVCmax was shorter in MO than in CG (p < 0.001). IVCCI was higher in MO (62.1 ± 23 %) vs. controls (42.6 ± 20.8; p < 0.001). Even left atrium anterior-posterior diameter was shorter in MO compared to CG.

CONCLUSIONS

Preoperative RWL may induce hypovolemia in morbidly obese patients. Hypovolemia in MO was more common vs. lean controls. TTE is a rapid and feasible tool for assessment of preload even in morbid obesity.

Current and future practices in surgical retraction

Retraction of tissues and anatomical structures is an essential component of all forms of surgery. The means by which operative access is gained through retraction are many and diverse. In this article, the various forms of retraction methods currently available are reviewed, with special reference to hand held, self-retaining and compliant techniques. The special challenges posed by laparoscopic surgery are considered and future developments in new retraction techniques are anticipated.

Laparoscopic ventral hernia repair in obese patients under spinal anesthesia

PURPOSE

The aim of the present study was to evaluate the feasibility and efficacy of laparoscopic ventral hernia repair under spinal anesthesia in obese patients (BMI > 30 kg/m(2)).

METHODS

From January 2007 to February 2010, 23 obese patients had their elective laparoscopic ventral hernia repair under spinal anesthesia. We looked primarily for intra-operative incidences as well as immediate postoperative complications. Long term results and especially recurrences were also to be evaluated.

RESULTS

Median operative time was 55 min (range 20-100). Intraoperatively, six patients (26%) complained of shoulder pain, three patients (13%) developed bradycardia and two (8.7%) hypotension. Postoperatively, nausea and/or vomiting were recorded in four patients (17.4%), four patients (17.4%) experienced urinary retention and one patient developed wound infection. Median pain score at 4th, 8th and 24th postoperative hour was 0.5 (0-5), 1.5 (0-6), and 1.5 (0-5) respectively. The median length of hospital stay was one day (1-2). At a median follow up of 39 months, one patient was diagnosed with a recurrence.

CONCLUSION

Spinal anesthesia for LVHR in obese patients (BMI > 30 kg/m(2)) proved an efficient and safe alternative to general anesthesia in the given patient sample.

Equal ratio ventilation (1:1) improves arterial oxygenation during laparoscopic bariatric surgery: A crossover study

Background:

Hypoxaemia and high peak airway pressure (Ppeak) are common anesthetic problems during laparoscopic bariatric surgery. Several publications have reported the successful improvement in arterial oxygenation using positive end expiratory pressure and alveolar recruitment maneuver, however, high peak airway pressure during laparoscopic bariatric surgery may limit the use of both techniques. This study was designed to determine whether equal I:E (inspiratory-to-expiratory) ratio ventilation (1:1) improves arterial oxygenation with parallel decrease in the Ppeak values.

Methods:

Thirty patients with a body mass index ≥40 kg/m² scheduled for laparoscopic bariatric surgery were randomized, after creation of pneumoperitoneum, to receive I:E ratio either 1:1 (group 1, 15 patients) or 1:2 (group 2, 15 patients). After a stabilization period of 30 min, patients were crossed over to the other studied I:E ratio. Ppeak, mean airway pressure (Pmean), dynamic compliance (Cdyn), arterial blood gases and hemodynamic data were collected at the end of each stabilization period.

Results:

Ventilation with I: E ratio of 1:1 significantly increased partial pressure of O₂ in the arterial blood (PaO₂), Pmean and Cdyn with concomitant significant decrease in Ppeak compared to ventilation with I: E ratio of 1:2. There were no statistical differences between the two groups regarding the mean arterial pressure, heart rate, respiratory rate, end tidal CO₂ or partial pressure of CO₂ in the arterial blood.

Conclusion:

Equal ratio ventilation (1:1) is an effective technique in increase PaO₂ during laparoscopic bariatric surgery. It increases Pmean and Cdyn while decreasing Ppeak without adverse respiratory or hemodynamic effects.

Prolonged inspiratory time produces better gas exchange in patients undergoing laparoscopic surgery: A randomised trial

BACKGROUND

Laparoscopic surgery performed with a patient in the Trendelenburg position is known to have adverse effects on pulmonary gas exchange and respiratory mechanics. We supposed that prolonged inspiratory time can improve gas exchange at lower airway pressure.

METHODS

One hundred patients undergoing gynaecologic laparoscopic surgery were randomly assigned to one of four groups: conventional inspiratory-to-expiratory (I : E) ratio (Group 1 : 2), I : E ratio of 1 : 1 (Group 1 : 1), 2 : 1 (Group 2 : 1), or 1 : 2 with external positive end-expiratory pressure (PEEP) of 5 cmH2 O (Group 1 : 2 PEEP). Tidal volume was set to 6 ml/kg, and I : E ratio was adjusted at the onset of pneumoperitoneum. Arterial blood gas analysis with measurements of partial pressure of arterial oxygen/fraction of inspired oxygen (PaO2 /FiO2 ), and physiologic dead space-to-tidal volume ratio (VD /VT ) was performed 15 min after anaesthetic induction (T1), and 30 (T2) and 60 min (T3) after onset of CO2 insufflation.

RESULTS

PaO2 /FiO2 at T3 in Groups 1 : 1, 2 : 1, and 1 : 2 PEEP were higher than Group 1 : 2. The partial pressure of arterial carbon dioxide at T3 in Group 2 : 1 was lower than the other groups. The VD /VT at T2 and T3 were lower in Groups 1 : 1 and 2 : 1 than Groups 1 : 2 and 1 : 2 PEEP. Peak or plateau airway pressure was higher in Group 1 : 2 PEEP than the other groups.

CONCLUSIONS

A prolonged inspiratory time demonstrated a beneficial effect on oxygenation. Furthermore, it showed better CO2 elimination without elevating the peak or plateau airway pressure compared with applying external PEEP. In terms of gas exchange and respiratory mechanics, a prolonged inspiratory time appears to be superior to applying external PEEP in patients undergoing laparoscopic surgery in the Trendelenburg position.

Anesthetic implications of obesity in the surgical patient

The obese patient presents many challenges to both anesthesiologist and surgeon. A good understanding of the pathophysiologic effects of obesity and its anesthetic implications in the surgical setting is critical. The anesthesiologist must recognize increased risks and comorbidities inherent to the obese patient and manage accordingly, optimizing multisystem function in the perioperative period that leads to successful outcomes. Addressed from an organ systems approach, the purpose of this review is to provide surgical specialists with an overview of the anesthetic considerations of obesity. Minimally invasive surgery for the obese patient affords improved analgesia, postoperative pulmonary function, and shorter recovery times at the expense of a more challenging intraoperative anesthetic course. The physiologic effects of laparoscopy are discussed in detail. Although laparoscopy's physiologic effects on various organ systems are well recognized, techniques provide means for compensation and reversing such effects, thereby preserving good patient outcomes.

Effects of the pneumoperitoneum and Trendelenburg position on respiratory mechanics in the rats by the end-inflation occlusion method

PURPOSE:

To describe the consequences of the cranial displacement of the diaphgram occurring during pneumoperitoneum (Pnp) and/or Trendelenburg (Tnd) position on respiratory mechanics. Possible addictive effects and the changes of the viscoelastic respiratory system resistance were studied, which were not extensively described before.

METHODS:

The end-inflation occlusion method was applied on eight rats. It allows us to determine mechanical parameters such as respiratory system static elastance, the ohmic resistance due to frictional forces in the airways, and the additional viscoelastic impedance due to tissues deformation. Measurements during mechanical ventilation were taken in controls (supine position), after 20–25° head-down tilting (Tnd), after abdominal air insufflation up to 12 mmHg abdominal pressure in the supine position (Pnp), and combining Tnd + Pnp. Tnd and Pnp modalities were similar to those commonly applied during surgical procedures in humans.

RESULTS:

We confirmed the previously described detrimental effects on respiratory mechanics due to the diaphgram displacement during both Pnp and Tnd. The increment in the total resistive pressure dissipation was found to depend primarily on the effects on the viscoelastic characteristics of the respiratory system. Data suggesting greater effects of Pnp compared to those of Tnd were obtained.

CONCLUSION:

The cranial displacement of the diaphgram occurring as a consequence of Pnp and/or Tnd, for example during laparoscopic surgical procedures, causes an increment of respiratory system elastance and viscoelastic resistance. The analysis of addictive effects show that these are more likely to occur when Pnp + Tnd are compared to isolated Tnd rather than to isolated Pnp.

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.

Use of microcatheter for intraabdominal survey

BACKGROUND

Laparoscopy is the most common procedure for minimally invasive intraabdominal surveys. Patients with pulmonary hypertension (PHTN) may need an alternate approach because the systemic absorption of carbon dioxide may lead to hypercapnia, acidemia, and increases in systemic and pulmonary pressures. We report a case of intraabdominal survey using a microcatheter trocar (Check-Flo Introducer) in a patient with a large adnexal mass and PHTN.

CASE

An adolescent girl with severe PHTN and multiple cardiac anomalies presented with oligomenorrhea. During the course of workup, an ultrasound revealed an 8-cm simple cyst in the right adnexa, which required removal. The decision was made to proceed with cystectomy. The patient was not a candidate for laparoscopy, and an alternative method was used. The Check-Flo Introducer, a microcatheter trocar; crystalloid fluid infusion; and a 3-mm laparoscopic camera were used to survey the abdominal cavity, revealing a 10-cm simple paratubal cyst that could be safely drained and removed via a minilaparotomy incision.

CONCLUSION

The microcatheter trocar is a useful and novel alternative in patients who cannot tolerate increases in intraabdominal pressure.

Perioperative management of the morbidly obese adolescent with heart failure undergoing bariatric surgery

The incidence and prevalence of adolescent obesity and adolescent heart failure are increasing, and anesthesiologists increasingly will encounter patients with both conditions. A greater understanding of the physiologic challenges of adolescent heart failure as they relate to the perioperative stressors of anesthesia and bariatric surgery is necessary to successfully manage the perioperative risks faced by this growing subpopulation. Here, we present a representative case of a morbidly obese adolescent with heart failure who underwent a laparoscopic bariatric operation and review the limited available literature on perioperative management in this age group. Specifically, we review evidence and offer recommendations related to preoperative evaluation, venous thromboembolism prophylaxis, positioning, induction, airway management, monitoring, anesthetic maintenance, ventilator management, and adverse effects of the pneumoperitoneum, rhabdomyolysis, and postoperative care.

Missed Inadvertent Gastrointestinal Injuries during Abdominal Operations: Characteristics, Diagnosis, and Treatment

Inadvertent gastrointestinal tract injuries (IGITI) during abdominal operations increase postoperative morbidity. Common mechanisms for this type of injury are not well-defined. The risk factors associated with an increase in missed IGITI during elective abdominal surgery and a possible strategy that may contribute to early diagnosis were not previously evaluated. Between 1998 and 2006, all the patients who underwent a subsequent laparotomy within 30 days of an index operation were identified. Patients reoperated for missed IGITI, defined as perforation at sites other than previous anastomosis or bowel repair, were collected. Data pertaining to patients, disease, and primary operations’ characteristics, as well as reoperation findings and outcomes were studied. Methods of diagnosis of perforation for each particular patient were assessed. Thirty-two patients (15 females, 17 males) underwent a second operation for gastrointestinal tract leak within 30 days of an index surgery due to missed IGITI. The mean age was 59.5 ± 18.2 years (range 21–87). The average time between the first and second operation was 5.3 ± 3.5 days (range 1–13). Adhesions (27 patients), previous operations (20 patients), and laparoscopic approach (13 patients) were the most commonly documented factors that may result in missed IGITI. Diagnosis of gastrointestinal leak due to missed IGITI was made clinically in 12 patients. Twenty patients underwent contrast study before reoperation. Careful selection of patients and type of surgery in addition to awareness of this rare complication may decrease the frequency of missed IGITI, lead to earlier diagnosis, and possibly improve outcomes.

Impact of Body Mass Index on Outcomes of Laparoscopic Adrenal Surgery

Objective. The aim of this article is to define the relationship between body mass index (BMI) and outcomes of laparoscopic adrenalectomy. Method. A total of 172 patients were eligible for inclusion in the study. The patients were divided into 3 groups: group I, normal weight; group II, overweight; and group III, obesity. Perioperative outcomes were compared between the groups. Results. The median operative time was 72, 75, and 90 minutes in groups I, II, and III, respectively. The median blood loss was <50 mL in all groups. There were no intraoperative blood transfusions. There was no statistical difference in the rate of intraoperative incidences and postoperative complications. Moderately increased operative time was the only perioperative parameter that statistically differed from nonobese patients. The regression analysis found significant but weak correlation between BMI and operative time. The BMI did not correlate with other surgical outcomes. Conclusions. Laparoscopic adrenal surgery for obese patients can be done as safely as for nonobese patients.

The evolution of minimally invasive bariatric surgery

The number of bariatric operations performed annually in the U.S. for the treatment of severe obesity [body mass index (BMI)≥40 kg/m2] has increased tenfold since the mid 1990s, with approximately 220,000 operations performed in 2009. This article reviews the evolution of laparoscopic bariatric surgery over the last 20 years. The results of the most common procedures are analyzed and current and future trends described.

Factors Predictive of Venous Thromboembolism in Bariatric Surgery

Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in bariatric surgery. The aim of this study was to evaluate the effect of patient characteristics, payer type, comorbidities, and surgical techniques on development of VTE in bariatric surgery. Using the National Inpatient Sample (NIS) database from 2006 to 2008, clinical data of 304,515 morbidly obese patients who underwent bariatric surgery were examined. Multiple regression analysis was performed to identify factors predictive of VTE. The overall rate of in-hospital VTE was 0.17 per cent, with the highest rate of VTE observed in open gastric bypass (0.45%). The VTE rate was significantly lower in laparoscopic compared with open gastric bypass (0.13% vs 0.45%, respectively, P < 0.01) and in nongastric bypass compared with gastric bypass procedures (0.06% vs 0.21%, respectively, P < 0.01). Alcohol abuse [odds ratio (OR): 8.7], open operation (OR: 2.5), gastric bypass procedures (OR: 2.4), renal failure (OR: 2.3), congestive heart failure (OR: 2.0), male gender (OR: 1.5), and chronic lung disease (OR: 1.4) were associated with a higher rate of VTE. This study identified several significant risk factors for development of VTE in bariatric surgery. To minimize the risk of VTE, surgeons may consider these factors in selection of appropriate prophylaxis and bariatric surgical options.

The effect of increased hip flexion using stirrups on lower-extremity venous flow: a prospective observational study

BACKGROUND

Patient positioning during surgeries for colorectal cancer may represent an unrecognized risk factor for deep venous thrombosis.

METHODS

Twelve healthy control patients were positioned supine with knee flexion at 90°. Duplex ultrasound examined common femoral vein (CFV) and proximal femoral vein diameter, peak systolic velocity, and volume flow with hip flexion at 0°, 30°, 60°, and 90°. Data were analyzed using the paired t test.

RESULTS

In the CFV, hip flexion to 90° was associated with a significant increase in mean volume flow when compared with hip flexion at 0° (.59 vs .36 L/min; P = .05) and 30° (.59 vs .35 L/min; P = .038). In both the CFV and proximal femoral vein, increased hip flexion was associated with significantly reduced vessel diameter and increased peak systolic velocity.

CONCLUSIONS

Intraoperative positioning of the lower extremities represents a modifiable risk factor for deep venous thrombosis. When stirrups are used, hip flexion of 90° maximizes venous drainage from the legs.

Changes in cerebral oximetry during peritoneal insufflation for laparoscopic procedures

Background:

Changes in cardiac output may occur during insufflation for laparoscopic procedures. However, there are limited data regarding its potential effects on cerebral oxygenation.

Materials and Methods:

Cerebral oxygenation (ScO₂), end tidal CO₂, heart rate, blood pressure and oxygen saturation by pulse oximetry were recorded every 5 minutes prior to insufflation, during insufflation and after desufflation. Minute ventilation was increased to maintain normocapnia and the depth of anesthesia was adjusted or fluids/phenylephrine administered to maintain the blood pressure within 20% of the baseline.

Results:

The cohort for the study included 70 adults for laparoscopic herniorrhaphy, gastric bypass or cholecystectomy. A total of 1004 ScO₂ values were obtained during laparoscopy. The ScO₂ decreased from the baseline in 758 of the 1004 data points. The ScO₂ was 0–9 less than the baseline in 47.8% of the values, 10–19 less than the baseline in 24.9% of the values and 20–29 less than the baseline in 26 values (2.6%). Eighty-two (8.2%) of the values were less than 80% of the baseline value, while 25 values (2.5%) were less than 75% of the baseline value. Twelve patients had at least one ScO₂ value that was less than 80% of the baseline and 6 had at least one ScO₂ value that was less than 75% of the baseline. Four patients of the cohort had ScO₂ values less than 80% of the baseline for more than 50% of the laparoscopic procedure.

Conclusions:

Although relatively uncommon, significant changes in cerebral oxygenation do occur in some patients during insufflation for laparoscopic surgery.

[Perioperative anesthetic management of 300 morbidly obese patients undergoing laparoscopic bariatric surgery and a brief review of relevant pathophysiology]

OBJECTIVES

Laparoscopic bariatric surgery is a challenge for anesthesiologists because morbidly obese patients are at high risk and laparoscopy may complicate respiratory and hemodynamic management. The aim of this study was to analyze the perioperative anesthetic management of morbidly obese patents undergoing laparoscopic bariatric surgery.

MATERIAL AND METHODS

Prospective study of 300 consecutive patients diagnosed with morbid obesity and scheduled for laparoscopic bariatric surgery. Patients were positioned with a wedge cushion under the head and shoulders. A rapid sequence induction of anesthesia was carried out. A short-handled, articulated-blade McCoy laryngoscope was used for intubation; an intubation laryngeal mask airway (Fastrach) was on hand as a rescue device. Propofol and remifentanil were used for maintenance of anesthesia and morphine was administered at the end of surgery. Incentive spirometry was initiated in the postanesthetic recovery unit.

RESULTS

Eighty percent of the patients were women with a mean (SD) body mass index (kg/m2) of 46 (5). The first choice of direct laryngoscopic intubation was successful in 98.6% of cases. All patients were successfully intubated. Only 5 patients required intensive care. Postoperative complications (mainly respiratory problems, bleeding, and infections) were observed in 17%. No patient died.

CONCLUSIONS

Perianesthetic management of morbidly obese patients who undergo laparoscopic surgery is safe. To minimize pulmonary complications, preoxygenation and rapid sequence induction should be performed correctly and incentive spirometry should be initiated in the immediate postoperative period. The McCoy laryngoscope ensures intubation in most cases.

Massive ovarian cyst and sudden death

Massive enlargement of an ovarian cyst is an uncommon cause of morbidity and a rare cause of mortality due in large to part to noninvasive imaging techniques that usually permit early detection. When an ovarian cyst reaches giant proportions, it produces abdominal enlargement often with a fluid wave resulting in a condition that mimics ascites, called pseudoascites. Despite their impressive appearances, such cysts often are operable for cure. We describe a case of a middle-aged woman who presented 3 years before her death with symptoms from an undiagnosed giant cyst and given a diagnosis of ascites of undetermined etiology. She subsequently died at home unexpectedly, and at autopsy, she was found to have a massively enlarged but otherwise benign mucinous cystadenoma.

Laparoscopic Roux-en-Y gastric bypass in patients with body mass index >70 kg/m2

BACKGROUND

Sparse published data support the optimal surgical management of megaobesity (body mass index >70 kg/m(2)). The purpose of the present study was to compare laparoscopic Roux-en-Y gastric bypass (LRYGB) and open Roux-en-Y gastric bypass (ORYGB) in megaobese patients.

METHODS

We conducted a retrospective review of 89 consecutive patients with a body mass index >70 kg/m(2) who underwent LRYGB or ORYGB from January 2003 to May 2007 at the Ohio State University Medical Center.

RESULTS

LRYGB was performed in 37 patients, with 3 conversions to open surgery, and 52 underwent ORYGB. No statistically significant demographic or preoperative co-morbidity differences were discerned. The mean intraoperative blood loss was lower in the LRYGB group (54 mL versus 211 mL; P < .0001). The median length of stay for both LRYGB and ORYGB groups was 4 days. One patient in the open group died. The postoperative complications were statistically equivalent between the 2 groups. The hernia rate for the LRYGB group was 3% and was 19% in the ORYGB group (P = .02). The patients who underwent LRYGB had greater excess body weight loss at 3 (22.7% versus 17.5%, P = .02) and 6 (37.5% versus 30.5%, P = .03) months. However, the average excess body weight loss at 12 and 24 months was similar (48% and 60%, respectively).

CONCLUSION

LRYGB is a technically feasible and safe surgical approach in the megaobese. The intraoperative blood loss was less with LRYGB than with ORYGB. The overall mortality and complications were not different, with the exception of hernia frequency, which was significantly greater after ORYGB. The percentage of excess body weight loss at 3 and 6 months was better for the LRYGB group. In both groups of patients, the 12- and 24-month excess body weight loss were similar.

Supplemental postoperative oxygen and tissue oxygen tension in morbidly obese patients

BACKGROUND

Subcutaneous tissue oxygen tension (PsqO(2)) is a major predictor for wound healing and the occurrence of wound infections. Perioperative subcutaneous wound and tissue oxygen tension is significantly reduced in morbidly obese patients. Even during intraoperative supplemental oxygen administration, PsqO(2) remains low. Tissue hypoxia is pronounced during surgery and might explain the substantial increase in infection risk in obese patients. It remains unknown whether long-term supplemental postoperative oxygen augments tissue oxygen tension. Consequently, we tested the hypothesis that 80% inspired oxygen administration during 12-18 postoperative hours significantly increases PsqO(2) compared to 30% inspired oxygen fraction.

METHODS

After IRB approval and informed consent, 42 patients undergoing laparoscopic bariatric surgery were randomly assigned to receive either 80% inspired oxygen via a PULMANEX Hi-Ox Mask (Viasys MedSystems, Wheeling, IL) (10 L/min) or 30% oxygen via nasal cannula (2 L/min) after surgery until the next morning. PsqO(2) was measured with a temperature-corrected Clark-type electrode in the subcutaneous tissue of the upper arm and adjacent to the wound.

RESULTS

Postoperative subcutaneous tissue oxygen tension was significantly increased in the Hi-Ox group: 58 (47.7, 74.1) mmHg vs. 43 (38.7, 55.2) mmHg, P = 0.002. Also, wound tissue oxygen tension was improved during supplemental oxygen administration: 75.2 (69.8, 95.5) mmHg vs. 52.4 (46.3, 66.1) mmHg, P < 0.001.

CONCLUSION

Subcutaneous tissue oxygen tension was significantly increased by supplemental postoperative oxygen administration. Whether there is an effect on the incidence of wound infection in morbidly obese patients is matter of further research.

Preoperative use of incentive spirometry does not affect postoperative lung function in bariatric surgery

Morbidly obese patients undergoing general anesthesia for laparoscopic bariatric surgery are considered at increased risk of a postoperative decrease in lung function. The purpose of this study was to determine whether a systematic use of incentive spirometry (IS) prior to surgery could help patients to preserve their respiratory function better in the postoperative period. Forty-one morbidly obese (body mass index [BMI] > 40 kg/m²) candidates for laparoscopic bariatric surgery were consented in the study. All patients were taught how to use an incentive spirometer but then were randomized blindly into 2 groups. The control group was instructed to use the incentive spirometer for 3 breaths, once per day. The treatment group was requested to use the incentive spirometer for 10 breaths, 5 times per day. Twenty experimental (mean BMI of 48.9 ± 5.67 kg/m²) and 21 control patients (mean BMI of 48.3 ± 6.96 kg/m²) were studied. The initial mean inspiratory capacity (IC) was 2155 ± 650.08 (SD) cc and 2171 ± 762.98 cc in the experimental and control groups, respectively. On the day of surgery, the mean IC was 2275 ± 777.56 cc versus 2254.76 ± 808.84 cc, respectively. On postoperative day 1, both groups experienced a significant drop of their IC, with volumes of 1458 ± 613.87 cc (t test P < 0.001) and 1557.89 ± 814.67 cc (t test P < 0.010), respectively. Our results suggest that preoperative use of the IS does not lead to significant improvements of inspiratory capacity and that it is a not a useful resource to prevent postoperative decrease in lung function.

Use of the valveless trocar system reduces carbon dioxide absorption during laparoscopy when compared with standard trocars

OBJECTIVES

To prospectively compare a novel type of valveless trocar that creates a curtain of pressurized carbon dioxide [CO(2)] gas (which maintains pneumoperitoneum at a lower gas flow rate) with standard trocars; to quantify the volume of CO(2) used; and to characterize CO(2) elimination during laparoscopic renal surgery.

METHODS

A total of 51 patients undergoing laparoscopic renal surgery by a single surgeon were prospectively evaluated using either the valveless trocar (n = 26) or standard trocars (n = 25). Patient demographics, operative time, volume of CO(2) gas consumed, CO(2) elimination, perioperative parameters, and postoperative complications were recorded and analyzed.

RESULTS

Both patient cohorts were comparable in their preoperative demographics, including body mass index, the number of patients with chronic obstructive pulmonary disease, and smoking history. Mean operative time was lower in the valveless trocar cohort (124.1 minutes) compared with the conventional trocar group (145.6 minutes), P = .047. Use of the valveless trocar was associated with a lower volume of intraoperative CO(2) consumed (120.0 ± 82.8 vs 300.6 ± 191.5; P < .001) and reduced CO(2) elimination compared with standard trocar use after the first 16 minutes of insufflation (P < .05). Minimal complications occurred, including 2 cases of subcutaneous emphysema in the valveless trocar group, and 1 case of respiratory acidosis in the conventional trocar group.

CONCLUSIONS

Use of a valveless trocar significantly reduced CO(2) consumption during transperitoneal laparoscopy. The valveless trocar also demonstrated significantly reduced CO(2) elimination and absorption when compared with the standard trocar.

Inclusion of a nitric oxide congener in the insufflation gas repletes S-nitrosohemoglobin and stabilizes physiologic status during prolonged carbon dioxide pneumoperitoneum

A method to maintain organ blood flow during laparoscopic surgery has not been developed. Here we determined if ethyl nitrite, an S-nitrosylating agent that would maintain nitric oxide bioactivity (the major regulator of tissue perfusion), might be an effective intervention to preserve physiologic status during prolonged pneumoperitoneum. The study was conducted on appropriately anesthetized adult swine; the period of pneumoperitoneum was 240 minutes. Cohorts consisted of an anesthesia control group and groups insufflated with CO2 alone or CO2 containing fixed amounts of ethyl nitrite (1-300 ppm). Insufflation with CO2 alone produced declines in splanchnic organ blood flows and it reduced circulating levels of S-nitrosohemoglobin (i.e., nitric oxide bioactivity); these reductions were obviated by ethyl nitrite. In a specific example, preservation of kidney blood flow with ethyl nitrite kept serum creatinine and blood urea nitrogen concentrations constant whereas in the CO2 alone group both increased as kidney blood flow declined. The data indicate ethyl nitrite can effectively attenuate insufflation-induced decreases in organ blood flow and nitric oxide bioactivity leading to reductions in markers of acute tissue injury. This simple intervention provides a method for controlling a major source of laparoscopic-related morbidity and mortality: tissue ischemia and altered postoperative organ function.

Gasless balloon laparoscopy

BACKGROUND

The concept of balloon laparoscopy (B-LSC) pursues the simplification of conventional diagnostic laparoscopy (LSC). The pneumoperitoneum is replaced by a transparent balloon, which is positioned in front of the optical system. It shall be shown that with this arrangement diagnostic LSC can be performed outside of the operating room without requiring general anesthesia.

METHODS

An inflatable balloon was developed for a 30 degrees /3.5-mm rod lens. Intra-abdominally the balloon was expanded to a diameter of 30 mm by air insufflation, and B-LSC was performed. Twelve patients were examined in general anesthesia before laparoscopic surgery. Twelve patients were subjected to B-LSC fully awake or with sedation (midazolam or propofol/S-ketamine) as a "second-look" procedure by way of a flexible trocar (port) left in the abdominal wall at the end of previous operation. Eight patients have been first provided with a trocar under sedation (midazolam or propofol/S-ketamine) combined with local anesthesia, and B-LSC was performed before laparoscopic surgery.

RESULTS

On a scale of 1-5, the general impression was rated 1.9, the navigability to the different abdominal organs 2.5, the resolution 1.5, the stability of the system optic/trocar 2.1, the suitability of the balloon format 1.9, and the stability of the balloon against lateral shear forces 2.4. The degree of painfulness of the examination was rated 2.8, the tolerance of the port 1.4, and the degree of painfulness of trocar placement at 2.5. On a scale of 1 to 3, the strain of the abdominal musculature was rated 1.4 and the obstruction by adhesions 1.7.

DISCUSSION

B-LSC is technically practicable with good imaging qualities and without requiring pneumoperitoneum. It is tolerated in great extent under slight sedation and particularly well under deep sedation. The procedure is suitable for diagnostics of unclear abdominal conditions, as a second-look LSC and also as a staging LSC.