Warming and Humidification of Insufflation Carbon Dioxide in Laparoscopic Colonic Surgery: A Double-Blinded Randomized Controlled Trial

Intraoperative Patient Warming Instead of Gas on the Management of Postoperative Pain in Laparoscopic Colectomy and Cholecystectomy: A Randomized Controlled Trial

INTRODUCTION

Blurred lines remain in details of the association between patient warming with postoperative pain and a proper analgesic requirement. Therefore, the present study proposes to observe the effects of intraoperative patient warming and carbon dioxide insufflation duration in laparoscopic colectomy (LCol) and laparoscopic cholecystectomy (LChol) procedures on postoperative pain, analgesic requirements, and hemodynamics.

METHODS

The present study involved 80 cases aged 18-80 years with the American Society of Anesthesiologists I-III classification, possessing two initial groups primarily, one for LCol and one for LChol. Subsequently, each was divided into two through randomization for intraoperative warming. Postoperatively, pain perception, per se, was evaluated using the visual analog scale (VAS) score at the 30 minutes, 1st, 6th, 12th, and 24th hours, along with the impact of pain on hemodynamic parameters and side effects such as nausea/vomiting and the dosage of analgesics used.

RESULTS

Groups actively heated with warm air-blowing devices detected significantly higher intraoperative core and skin temperature measurements, and postoperative early pain perception was significantly lower in the warmed ones. Furthermore, a significant decrease in the VAS scores and the analgesic at the 12th and 24th hours compared to the first six hours was recognized between them.

CONCLUSION

Consequently, herewith, we postulate that so-called patient warming positively affects the VAS scores.

Effect of heating insufflation tube of AirSeal system on laparoscopic surgery

The AirSeal system (CONMED, NY, USA) can outstandingly keep pneumoperitoneum stable. However, water droplets form on the access port, impairing the performance of comfortable surgical procedures because of the resultant wet surgical field. This study was performed to clarify the mechanism of water droplet formation and to prevent it. Condensation was observed on the AirSeal system. A heater was wrapped around the tri-lumen tube, and the heating effect was assessed. The simulator experiments revealed that condensation formed in the tri-lumen tube and on the wall of the access port. The accumulated weight of the condensation on the wall of the access port was 41.6 g in the Heated group, 138.2 g in the Control group, and 479.4 g in the Cooled group. In the clinical assessment, the accumulated volume of the condensation attached to the inside wall was significantly smaller in the Heated group than in the Unheated group (111.7 g vs. 332.9 g, respectively). We clarified that the volume of condensation attached to the wall of the access port depended on the temperature of the tri-lumen tube. The clinical study revealed that the condensation on the access port was reduced by heating the tri-lumen tube. The development of a novel heating device for the insufflation tube would be effective and useful.

The role of warmed-humidified carbon dioxide insufflation in colorectal surgery: A systematic review and meta-analysis

BACKGROUND

Maintenance of normothermia is a crucial part of enhanced recovery after colorectal surgery. Dry-cold carbon dioxide (CO2 ) traditionally used for insufflation in laparoscopic surgery and negative pressure operating theatres has been associated with intraoperative hypothermia. Studies suggest that use of warmed-humidified CO2 may promote normothermia. However, due to a scarcity of high-quality studies demonstrating a proven benefit on intraoperative core body temperature, its use in colorectal surgery remains limited. Therefore, the aim of this review was to evaluate the effects of warmed-humidified CO2 compared to traditional dry-cold CO2 , or ambient air in operating theatres, during colorectal surgery.

METHODS

A search of Medline, EMBASE, and CENTRAL was performed. Randomised controlled trials (RCTs) that compared patients receiving warmed-humidified CO2 with either dry-cold CO2 insufflation in laparoscopic procedures or no insufflation during open surgery were included. The primary outcome was change in intraoperative core body temperature. Secondary outcomes included length of stay, operating time, return of gastrointestinal function, wound infection, and postoperative pain. A pairwise meta-analysis was performed using inverse variance random effects.

RESULTS

Among the six RCTs included, 208 patients received warmed-humidified CO2 (42.3% female, mean age: 65.8 years) and 210 patients received either dry-cold CO2 in laparoscopic procedures or no gas insufflation during open procedures (46.2% female, mean age: 66.1 years). No significant difference was found for change in intraoperative core body temperature (MD = 0.01, 95% CI: -0.1, 0.11, p = 0.90, very low certainty). Patients in the warmed-humidified CO2 group had significantly higher pain scores on postoperative day 1 (MD = 1.61, 95% CI: 0.91, 2.31, p < 0.05, very low certainty). No significant differences were found in any of the other secondary outcomes studied.

CONCLUSION

Patients undergoing colorectal surgery receiving warmed-humidified CO2 do not experience any clinically meaningful difference in core body temperature change compared to their counterparts receiving dry-cold CO2 insufflation or no insufflation. However, patients may report greater pain scores on postoperative day 1 with warmed-humidified CO2 . There is likely no clinically important difference between warmed-humidified CO2 and dry-cold CO2 for patients undergoing colorectal surgery. Patient, clinician, and institution factors should be considered when deciding between these two insufflation modalities.

Stop the Smudge: A Novel Solution to Loss of Vision During Laparoscopic Colorectal Surgery

BACKGROUND

An obscured vision of surgical field during laparoscopic surgery is inconvenient. Several temporary methods were described as solutions to loss of vision, and common practice is scope removal, cleaning, and heating. A lately developed and introduced device claims continuous clear vision during laparoscopic surgery. This study aims to present our initial experience with the device during laparoscopic colorectal surgery.

MATERIALS AND METHODS

We have included medical records of all patients scheduled for laparoscopic colorectal surgery with the device between March and August 2021 at Cleveland Clinic. Patient demographics, surgery type and time, the number of loss of vision events were recorded.

RESULTS

Fifteen patients underwent laparoscopic colorectal surgery during the study period. The median age was 42 (range: 25 to 86) years, and 10 (66%) were female. The median surgery time was 127 (range: 67 to 240) minutes, and the median loss of vision event number was 3 (1 to 6) per surgery. There was no need for laparoscope removal during any of the surgeries. All surgeries were completed without any intraoperative complications.

CONCLUSION

The novel system, provides clear vision during laparoscopic colorectal surgery with no need of scope removal for loss of vision events. The system provides removal of particulate gathering on the tip of the scope.

Effect of Surgical Humidification on Inflammation and Peritoneal Trauma in Colorectal Cancer Surgery: A Randomized Controlled Trial

BACKGROUND

Pre-clinical studies indicate that dry-cold-carbon-dioxide (DC-CO2) insufflation leads to more peritoneal damage, inflammation and hypothermia compared with humidified-warm-CO₂ (HW-CO2). Peritoneum and core temperature in patients undergoing colorectal cancer (CRC) surgery were compared.

METHODS

Sixty-six patients were randomized into laparoscopic groups; those insufflated with DC-CO2 or HW-CO2. A separate group of nineteen patients undergoing laparotomy were randomised to conventional surgery or with the insertion of a device delivering HW-CO2. Temperatures were monitored and peritoneal biopsies and bloods were taken at the start of surgery, at 1 and 3 h. Further bloods were taken depending upon hospital length-of-stay (LOS). Peritoneal samples were subjected to scanning electron microscopy to evaluate mesothelial damage.

RESULTS

Laparoscopic cases experienced a temperature drop despite Bair-Hugger^TM use. HW-CO2 restored normothermia (≥ 36.5 °C) by 3 h, DC-CO2 did not. LOS was shorter for colon compared with rectal cancer cases and if insufflated with HW-CO2 compared with DC-CO2; 5.0 vs 7.2 days, colon and 11.6 vs 15.4 days rectum, respectively. Unexpectedly, one third of patients had pre-existing damage. Damage increased at 1 and 3 h to a greater extent in the DC-CO2 compared with the HW-CO2 laparoscopic cohort. C-reactive protein levels were higher in open than laparoscopic cases and lower in both matched HW-CO2 groups.

CONCLUSIONS

This prospective RCT is in accord with animal studies while highlighting pre-existing damage in some patients. Peritoneal mesothelium protection, reduced inflammation and restoration of core-body temperature data suggest benefit with the use of HW-CO2 in patients undergoing CRC surgery.

The effect of warm and humidified gas insufflation in gynecological laparoscopy on maintenance of body temperature: a prospective randomized controlled multi-arm trial

Background

Hypothermia is defined as a decrease in body core temperature to below 36 °C. If intraoperative heat-preserving measures are omitted, a patient’s temperature will fall by 1 – 2 °C. Even mild forms of intraoperative hypothermia can lead to a marked increase in morbidity and mortality. Using warm and humidified gas insufflation in laparoscopy may help in the maintenance of intraoperative body temperature.

Methods

In this prospective randomized controlled study, we investigated effects of temperature and humidity of the insufflation gas on intra- and postoperative temperature management. 150 patients undergoing gynecologic laparoscopic surgery were randomly assigned to either insufflation with non-warmed, non-humidified CO₂ with forced air warming blanket (AIR), humidified warm gas without forced air warming blanket (HUMI) or humidified warm gas combined with forced air warming blanket (HUMI+). We hypothesized that the use of warmed laparoscopic gas would have benefits in the maintenance of body temperature and reduce the occurrence of hypothermia.

Results

The use of warm and humidified gas insufflation alone led to more hypothermia episodes with longer duration and longer recovery times as well as significantly lower core body temperature compared to the other two groups. In the comparison of the AIR group and HUMI + group, HUMI + patients had a significantly higher body temperature at arrival at the PACU (Post Anaesthesia Care Unit), had the least occurrence of hypothermia and suffered from less shivering.

Conclusion

The use of warm and humidified gas insufflation alone does not sufficiently warm the patients. The optimal temperature management is achieved in the combination of external forced air warming and insufflation of warm and humidified laparoscopy gas.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00404-022-06499-z.

Effects of Heated Pneumoperitoneum on Inflammation, Oxidative Stress, and Peritoneal Histology in Female Dogs That Underwent Video-Assisted Ovariohysterectomy

Laparoscopic procedures require the creation of pneumoperitoneum. CO₂, which must be cold and dry, is the standard gas used in such surgeries. The type of gas used, its temperature, and moisture may change the peritoneal surface and cause systemic and local oxidative stress. Our objective is to evaluate the influence of pneumoperitoneum heating on the occurrence of histological lesions in the peritoneum, inflammation, plasma oxidative stress, and on the mesothelial surface in patients undergoing video-assisted ovariohysterectomy. Twenty canine females were included and distributed evenly into two groups: heated CO₂ (HG) and unheated CO₂ (UHG). The biomarkers of inflammation and oxidative stress were evaluated before insufflation (T0), at 30 min (T1), and at 60 min (T2) of exposure to CO₂. Biopsies of the peritoneal tissue for histological evaluation were performed at T0 and T2. Regarding plasma parameters, acetylcholinesterase (AChE) showed a greater activity in the HG at T1 (p=0.0268) and T2 (p=0.0423); in turn, butyrylcholinesterase (BChE) showed a greater activity at T2 in the HG (p=0.0175) compared with T0. Catalase activity (CAT) was different between HG times; it was higher at T1 (p=0.0253). There was a decrease in the levels of substances reactive to thiobarbituric acid (TBARS) (p=0.0117) and in glutathione (GSH) (p=0.0114) between T0 and T2 in the UHG. Regarding tissue oxidative stress, the CAT in the HG showed a greater activity at T2 than T1 (p=0.0150). By comparing the groups at each time, there was a difference only at T2 (p=0.0288), being greater in the HG. Regarding the activity of superoxide dismutase (SOD) in the HG, there was a difference between T2 in relation to T0 and T1 (p=0.0181); finally, there was an increase only at T1 (p=0.0287) in the UHG when comparing groups at the same time. There were no differences in the histological parameters evaluated. Our study demonstrates that the heating of CO₂ generates a greater inflammatory response and forms reactive oxygen species (ROS) at the plasma and peritoneal levels.

Impact of STIMUlant and osmotic LAXatives (STIMULAX trial) on gastrointestinal recovery after colorectal surgery: randomized clinical trial

BACKGROUND

Recovery of gastrointestinal (GI) function is often delayed after colorectal surgery. Enhanced recovery protocols (ERPs) recommend routine laxative use, but evidence of benefit is unclear. This study aimed to investigate whether the addition of multimodal laxatives to an ERP improves return of GI function in patients undergoing colorectal surgery.

METHODS

This was a single-centre, parallel, open-label RCT. All adult patients undergoing elective colorectal resection or having stoma formation or reversal at the Royal Adelaide Hospital between August 2018 and May 2020 were recruited into the study. The STIMULAX group received oral Coloxyl® with senna and macrogol, with a sodium phosphate enema in addition for right-sided operations. The control group received standard ERP postoperative care. The primary outcome was GI-2, a validated composite measure defined as the interval from surgery until first passage of stool and tolerance of solid intake for 24 h in the absence of vomiting. Secondary outcomes were the incidence of prolonged postoperative ileus (POI), duration of hospital stay, and postoperative complications. The analysis was performed on an intention-to-treat basis.

RESULTS

Of a total of 170 participants, 85 were randomized to each group. Median GI-2 was 1 day shorter in the STIMULAX compared with the control group (median 2  (i.q.r. 1.5-4) versus 3 (2-5.5) days; 95 per cent c.i. -1 to 0 days; P = 0.029). The incidence of prolonged POI was lower in the STIMULAX group (22 versus 38 per cent; relative risk reduction 42 per cent; P = 0.030). There was no difference in duration of hospital day or 30-day postoperative complications (including anastomotic leak) between the STIMULAX and control groups.

CONCLUSION

Routine postoperative use of multimodal laxatives after elective colorectal surgery results in earlier recovery of gastrointestinal function and reduces the incidence of prolonged POI. Registration number: ACTRN12618001261202 (www.anzctr.org.au).

The effects of CO2 pneumoperitoneum at different temperature and humidity on hemodynamic and respiratory parameters and postoperative pain in gynecological laparoscopic surgery: A prospective randomized controlled study

BACKGROUND

It is recommended to heat and humidity CO₂ in laparoscopic surgery to prevent postoperative pain and hypothermia but information about its effects on hemodynamic and respiratory parameters is limited. We aimed to investigate the effects of standard and heated-humidified CO₂ on hemodynamic and respiratory parameters, body temperature and pain in healthy patients.

METHODS

One hundred patients who underwent total laparoscopic hysterectomy for benign pathology were divided into two groups: Group CD (cold-dry) patients were administered standard CO₂, while Group HH (heated-humidified) patients were administered 95% humidified insufflation at 37 °C. Hemodynamic and respiratory parameters, body temperature, pain score and blood count parameters were recorded.

RESULTS

A total of 96 patients were included in the study, taken from the 100 patients. Group HH (n:47) had only higher systolic blood pressure at 75, mean blood pressure at 50 and 55 and a lower heart rate between 15 and 45 min (p:0.049, 0.037, 0.013 respectively). Pain score, morphine consumption, end-tidal CO₂ and arterial blood gas values were not different between the groups, with only body temperature from 40 min and minimum value being significantly higher (at a difference of 0.86-1.04 °C) in Group HH. Postoperative leukocyte, neutrophil and NLR (neutrophil-leukocyte ratio) were found to be higher in this group (p < 0.05).

CONCLUSION

It has been found that both standard and heated-humidified CO₂do not constitute a problem in terms of hemodynamic and respiratory parameters in healthy patients. The heated-humidified CO₂group had only a higher core body temperature and inflammatory response.

TRIAL REGISTRATION

NCT04508387.

Modes of carbon dioxide delivery during laparoscopy generate distinct differences in peritoneal damage and hypoxia in a porcine model

BACKGROUND

Insufflation with CO₂ can employ continuous flow, recirculated gas and/or additional warming and humidification. The ability to compare these modes of delivery depends upon the assays employed and opportunities to minimize subject variation. The use of pigs to train colorectal surgeons provided an opportunity to compare three modes of CO₂ delivery under controlled circumstances.

METHODS

Sixteen pigs were subjected to rectal resection, insufflated with dry-cold CO₂ (DC-CO₂) (n = 5), recirculated CO₂ by an AirSeal device (n = 5) and humidification and warming (HW-CO2) by a HumiGard device (n = 6). Peritoneal biopsies were harvested from the same region of the peritoneum for fixation for immunohistochemistry for hypoxia-inducible factor 1 alpha (HIF-1α) and scanning electron microscopy (SEM) to evaluate hypoxia induction or tissue/cellular damage, respectively.

RESULTS

DC-CO₂ insufflation by both modes leads to significant damage to mesothelial cells as measured by cellular bulging and retraction as well as microvillus shortening compared with HW-CO₂ at 1 to 1.5 h. DC-CO₂ also leads to a rapid and significant induction of HIF-1α compared with HW-CO₂.

CONCLUSIONS

DC-CO₂ insufflation induces substantive cellular damage and hypoxia responses within the first hour of application. The use of HW-CO₂ insufflation ameliorates these processes for the first one to one and half hours in a large mammal used to replicate surgery in humans.

Randomized clinical trial of the effect of intraoperative humidified carbon dioxide insufflation in open laparotomy for colorectal resection

Background

Animal studies have shown that peritoneal injury can be minimized by insufflating the abdominal cavity with warm humidified carbon dioxide gas.

Methods

A single‐blind RCT was performed at a tertiary colorectal unit. Inclusion criteria were patient aged 18 years and over undergoing open elective surgery. The intervention group received warmed (37°C), humidified (98 per cent relative humidity) carbon dioxide (WHCO₂ group). Multiple markers of peritoneal inflammation and oxidative damage were used to compare groups, including cytokines and chemokines, apoptosis, the 3‐chlorotyrosine/native tyrosine ratio, and light microscopy on peritoneal biopsies at the start (T₀) and end (T_end) of the operation. Postoperative clinical outcomes were compared between the groups.

Results

Of 40 patients enrolled, 20 in the WHCO₂ group and 19 in the control group were available for analysis. A significant log(T_end/T₀) difference between control and WHCO₂ groups was documented for interleukin (IL) 2 (5·3 versus 2·8 respectively; P = 0·028) and IL‐4 (3·5 versus 2·0; P = 0·041), whereas apoptosis assays documented no significant change in caspase activity, and similar apoptosis rates were documented along the peritoneal edge in both groups. The 3‐chlorotyrosine/tyrosine ratio had increased at T_end by 1·1‐fold in the WHCO₂ group and by 3·1‐fold in the control group. Under light microscopy, peritoneum was visible in 11 of 19 samples from the control group and in 19 of 20 samples from the WHCO₂ group (P = 0·006). The only difference in clinical outcomes between intervention and control groups was the number of days to passage of flatus (2·5 versus 5·0 days respectively; P = 0·008).

Conclusion

The use of warmed, humidified carbon dioxide appears to reduce some markers related to peritoneal oxidative damage during laparotomy. No difference was observed in clinical outcomes, but the study was underpowered for analysis of surgical results. Registration number: NCT02975947 ( http://www.clinicaltrials.gov/).

Effect of different carbon dioxide (CO2) insufflation for laparoscopic colorectal surgery in elderly patients: A randomized controlled trial

BACKGROUND

Evidence suggests that dry CO2 insufflation during laparoscopic colorectal surgery results in greater structural injury to the peritoneum and longer hospital stay than the use of warm, humidified CO2. We aimed to test the hypothesis that warm, humidified CO2 insufflation could reduce postoperative pain and improve recovery in laparoscopic colorectal surgery.

METHODS

One hundred fifty elderly patients undergoing laparoscopic colorectal surgery under general anesthesia from May 2017 to October 2018 were randomly divided into 3 groups. The primary outcomes were resting pain, cough pain, and consumption of sufentanil at 2, 4, 6, 12, 24, and 48 hours postoperatively. Quality of visual image, hemodynamic changes, esophageal temperature, mean skin temperature, mean body temperature, recovery time, days to first flatus and solid food intake, shivering, incidence of postoperative ileus, length of hospital stay, surgical site infections, patients and surgeon satisfaction scores, adverse events, prothrombin time, activated partial thromboplastin time, and thrombin time were recorded.

RESULTS

Group CE patients were associated with significantly higher early postoperative cough pain and sufentanil consumption than the other 2 groups (P < .05). Compared with group CE, patients in both groups WH and CF had significantly reduced intraoperative hypothermia, recovery time of PACU, days to first flatus and solid food intake, and length of hospital stay, while the satisfaction scores of both patients and surgeon were significantly higher (P < .05). Prothrombin time, activated partial thromboplastin time, and thrombin time were significantly higher in group CE from 60 minutes after pneumoperitoneum to the end of pneumoperitoneum than the other 2 groups (P < .05). The number of patients with a shivering grade of 0 was significantly lower and grade of 3 was significantly higher in group CE than in the other 2 groups (P < .05).

CONCLUSION

Use of either warm, humidified CO2 insufflations or 20°C, 0% relative humidity CO2 combined with forced-air warmer set to 38°C during insufflations can both reduce intraoperative hypothermia, dysfunction of coagulation, early postoperative cough pain, sufentanil consumption, days to first flatus, solid food intake, and length of hospital stay.

Impact of different intraoperative CO2 pressure levels (8 and 15 mmHg) during laparoscopic hysterectomy performed due to benign uterine pathologies on postoperative pain and arterial pCO2 : a prospective randomised controlled clinical trial

OBJECTIVE

To compare the effects of two different intraoperative CO₂ pressures (8 and 15 mmHg) during laparoscopic hysterectomy for benign uterine pathologies in terms of postoperative abdominal and shoulder pain, laparoscopy-mediated vegetative alterations, pain medication requirement, arterial CO₂ pressure (pCO₂ ), surgical parameters, and safety.

DESIGN

Prospective randomised controlled study.

SETTING

German university hospital.

POPULATION

Female patients undergoing laparoscopic hysterectomy for benign uterine pathologies.

METHODS

Patients were randomised to a standard pressure (SP; 15 mmHg, control) or low-pressure (LP; 8 mmHg, experimental) group.

MAIN OUTCOME MEASURES

Primary outcomes were postoperative abdominal and shoulder pain intensities, measured via numeric rating scale (NRS) and vegetative parameters (fatigue, nausea, vomiting, bloating) at 3, 24, and 48 hours postoperatively. Secondary outcomes were pain medication requirement (mg) and arterial pCO₂ (mmHg). Surgical parameters and intra- and postoperative complications were also recorded.

RESULTS

In total, 178 patients were included. Patients in the LP group (n = 91) showed significantly lower postoperative abdominal and shoulder pain scores, fewer vegetative alterations, lower pain medication requirements, a shorter postoperative hospitalization, and lower intra- and postoperative arterial pCO₂ values compared with the SP group (n = 87; P ≤ 0.01). No differences in intra- and postoperative complications were observed between groups.

CONCLUSIONS

Low-pressure laparoscopy seems to be an effective and safe technique for the reduction of postoperative pain and laparoscopy-induced metabolic and vegetative alterations following laparoscopic hysterectomy for benign indications.

TWEETABLE ABSTRACT

Low-pressure laparoscopy seems to be an effective and safe technique for reduction of pain following laparoscopic hysterectomy.

The impact of warmed and humidified CO2 insufflation during robotic radical prostatectomy: Results of a randomized controlled trial

Background:

Cool and dry gas insufflation during laparoscopy induces hypothermia and cytokine increase, with significant perioperative morbidity. Our aim was to assess if warmed and humidified CO2 insufflation with HumiGard™ device can achieve significant benefits over standard insufflation in terms of risk of hypothermia, cytokine response, blood gases, and intra- and postoperative parameters, in the setting of robot-assisted radical prostatectomy (RARP).

Methods:

This was a prospective, randomized controlled clinical trial. Sixty-four patients with prostate cancer undergoing RARP were randomized to receive warmed and humidified CO2 insufflation with HumiGard device, plus hot air warming blanket (treatment group, H + WB), or standard CO2 insufflation, plus hot air warming blanket (control group, WB). Body core temperature (BCT), plasma levels of IL-6 and TNF-α, pain scores, and intraoperative parameters were recorded. The data were analyzed according to the Bayesian paradigm.

Results:

Intraoperative BCT increased in both groups during surgery, with a statistically significant difference favoring group H + WB, ending at 0.2°C higher on average than group WB. No difference across groups was shown for cytokine levels. Blood gas parameters were not affected by warmed CO2 insufflation. No statistical differences were noted for pain scores and the other intra- and postoperative parameters.

Conclusions:

During RARP, warm and humidified CO2 insufflation with the HumiGard device was more effective than the standard CO2 insufflation in maintaining the patient’s heat homeostasis, even if the difference was minimal. No imbalances were detected on blood gas analyses. No benefit could be shown in terms of cytokine levels and pain scores.

Randomized controlled trial comparing the effects of usual gas release, active aspiration, and passive-valve release on abdominal distension in patients who have undergone laparoscopic cholecystectomy

INTRODUCTION

Residual, intra-abdominal CO₂ contributes to abdominal distension and pain after laparoscopic surgery. The study was designed to assess recovery after gas release in patients who have undergone laparoscopic cholecystectomy (LC).

METHODS

A total of 142 patients undergoing laparoscopic cholecystectomy were randomly divided into three groups: (i) group 1 (control group), gas release from the surgical wound without port release (n = 47); (ii) group 2, active gas aspiration via a subdiaphragmatic port (n = 48); and (iii) group 3, passive-valve release via a subdiaphragmatic port valve opening (n = 47). Abdominal distension and shoulder pain levels were assessed postoperatively.

RESULTS

The active aspiration group had significantly reduced postoperative abdominal distensions at 30 min, 4, and 24 h compared with the control group (50.0% vs 80.9%, 43.8% vs 76.6%, 33.3% vs 57.4%, respectively; P < 0.05). Similarly, the passive-valve release group had significantly reduced postoperative abdominal distensions at 4 and 24 h compared with the control group (51.1% vs 76.6%, 57.4% vs 36.2%; P < 0.05). Both intervention groups had significantly reduced postoperative shoulder pain at 4 and 24 h compared with the control group (P < 0.001). In addition, the postoperative ambulation times for the active aspiration group were significantly shorter than those for the control and passive-valve release groups (P < 0.001).

CONCLUSION

Releasing residual CO₂ from the intra-abdominal cavity at the end of laparoscopic cholecystectomy by either the active aspiration or passive-valve release technique is an effective way to reduce postoperative abdominal distension and shoulder pain.

Effects of Intraoperative Insufflation With Warmed, Humidified CO2 during Abdominal Surgery: A Review

PURPOSE

During a laparotomy, the peritoneum is exposed to the cold, dry ambient air of the operating room (20°C, 0%-5% relative humidity). The aim of this review is to determine whether the use of humidified and/or warmed CO2 in the intraperitoneal environment during open or laparoscopic operations influences postoperative outcomes.

METHODS

A review was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed, OVID MEDLINE, Cochrane Central Register of Controlled Trials and Embase databases were searched for articles published between 1980 and 2016 (October). Comparative studies on humans or nonhuman animals that involved randomized controlled trials (RCTs) or prospective cohort studies were included. Both laparotomy and laparoscopic studies were included. The primary outcomes identified were peritoneal inflammation, core body temperature, and postoperative pain.

RESULTS

The literature search identified 37 articles for analysis, including 30 RCTs, 7 prospective cohort studies, 23 human studies, and 14 animal studies. Four studies found that compared with warmed/humidified CO2, cold, dry CO2 resulted in significant peritoneal injury, with greater lymphocytic infiltration, higher proinflammatory cytokine levels and peritoneal adhesion formation. Seven of 15 human RCTs reported a significantly higher core body temperature in the warmed, humidified CO2 group than in the cold, dry CO2 group. Seven human RCTs found lower postoperative pain with the use of humidified, warmed CO2.

CONCLUSION

While evidence supporting the benefits of using humidified and warmed CO2 can be found in the literature, a large human RCT is required to validate these findings.

Experimental study of delivery of humidified-warm carbon dioxide during open abdominal surgery

Background

The aim of this study was to monitor the effect of humidified‐warm carbon dioxide (HWCO₂) delivered into the open abdomen of mice, simulating laparotomy.

Methods

Mice were anaesthetized, ventilated and subjected to an abdominal incision followed by wound retraction. In the experimental group, a diffuser device was used to deliver HWCO₂; the control group was exposed to passive air flow. In each group of mice, surgical damage was produced on one side of the peritoneal wall. Vital signs and core temperature were monitored throughout the 1‐h procedure. The peritoneum was closed and mice were allowed to recover for 24 h or 10 days. Tumour cells were delivered into half of the mice in each cohort. Tissue was then examined using scanning electron microscopy and immunohistochemistry.

Results

Passive air flow generated ultrastructural damage including mesothelial cell bulging/retraction and loss of microvilli, as assessed at 24 h. Evidence of surgical damage was still measurable on day 10. HWCO₂ maintained normothermia, whereas open surgery alone led to hypothermia. The degree of tissue damage was significantly reduced by HWCO₂ compared with that in controls. Peritoneal expression of hypoxia inducible factor 1α and vascular endothelial growth factor A was lowered by HWCO₂. These effects were also evident at the surgical damage sites, where protection from tissue trauma extended to 10 days. HWCO₂ did not reduce tumorigenesis in surgically damaged sites compared with passive air flow.

Conclusion

HWCO₂ diffusion into the abdomen in the context of open surgery afforded tissue protection and accelerated tissue repair in mice, while preserving normothermia.

Warm and Humidified Versus Cold and Dry CO2 Pneumoperitoneum in Minimally Invasive Colon Resection: A Randomized Controlled Trial

INTRODUCTION

Peritoneal insufflation with warm-humidified (WH) CO₂ gas during minimally invasive surgical procedures is purported to prevent hypothermia and peritoneal desiccation and is associated with decreased postoperative IL-6 levels. This randomized study's purpose was to determine the clinical impact of WH versus cold-dry (CD) CO₂ in minimally invasive colon resection (MICR), and to assess perioperative plasma levels of IL-6, TIMP-1, sVEGF-R1, and HSP-70 after MICR.

METHODS

Operative and short-term clinical data plus perioperative blood samples were collected on MICR patients randomized to receive either WH (36.7°C, 95% humidity) or CD (room temperature, 0% humidity) CO₂ perioperatively. Peritoneal biopsies were taken at the start and end of surgery. Outcomes tracked included core temperature, postoperative in-hospital pain levels, analgesia requirements, and standard recovery parameters. Preoperative and postoperative days (PODs) 1 and 3 plasma protein levels were determined via ELISA.

RESULTS

A total of 101 patients were randomized to WH CO₂ (50) or CD CO₂ (51). The WH group contained more diabetics ( P = .03). There were no differences in indication, minimally invasive surgical method used, or core temperature. Pain scores were similar; however, the WH patients required less narcotics on PODs 1 to 3 ( P < .05), and less ketorolac on PODs 1 and 2 ( P < .03). No differences in length of stay, complication rates, or time to flatus/diet tolerance were noted. Plasma levels of the 4 proteins were similar postoperatively. Though insignificant, the WH group had less marked histologic changes on "end-of-case" peritoneal biopsies.

CONCLUSION

This study found significantly lower pain medication requirements for PODs 1 to 3 for the WH group; however, because there were no differences in the pains scores between the groups, firm conclusions regarding WH CO₂ cannot be made.

Impact of Laparoscopic Lens Contamination in Operating Theaters: A Study on the Frequency and Duration of Lens Contamination and Commonly Utilized Techniques to Maintain Clear Vision

INTRODUCTION

In laparoscopy, contamination of the distal lens is problematic. Not only a cause of frustration, repeatedly cleaning the laparoscope takes up significant time and disrupts the operative flow. Our study aims to explore and describe quantitatively this particular issue within the operating theaters of a major teaching hospital.

MATERIALS AND METHODS

We recorded data assessing the occurrence of impaired vision on the screen display and quantified the occurrence, duration, and modality of cleaning events. Data were recorded on a time-line sheet and collected for basic quantitative analysis as reported below. A brief interview with the surgeons was carried out at the end of each procedure.

RESULTS

A total of 64 hours of laparoscopy covering 25 procedures in 4 surgical disciplines were observed. The study found that 56% of the operation was performed with a clear display, while 37% of the time was spent impaired vision. Seven percent of the operation was spent cleaning the distal lens. The interviews recorded a unison sense of frustration and safety concerns regarding lens contamination.

CONCLUSIONS

Our observational study demonstrates that one third of the duration of a laparoscopic procedure is performed without perfectly clear display. The suboptimal display during an operation is similar to that of driving with a dirty windshield and having to step out of the car to clean it before continuing with the journey. The disruption to operative flow is transcribed as frustration felt by surgeons when display is compromised and having to clean the lens. However, the economical impact of cleaning the lens during the operation remains to be demonstrated.

Warmed, humidified CO2 insufflation benefits intraoperative core temperature during laparoscopic surgery: A meta-analysis

BACKGROUND

Intraoperative hypothermia is linked to postoperative adverse events. The use of warmed, humidified CO₂ to establish pneumoperitoneum during laparoscopy has been associated with reduced incidence of intraoperative hypothermia. However, the small number and variable quality of published studies have caused uncertainty about the potential benefit of this therapy. This meta-analysis was conducted to specifically evaluate the effects of warmed, humidified CO₂ during laparoscopy.

METHODS

An electronic database search identified randomized controlled trials performed on adults who underwent laparoscopic abdominal surgery under general anesthesia with either warmed, humidified CO₂ or cold, dry CO₂ . The main outcome measure of interest was change in intraoperative core body temperature.

RESULTS

The database search identified 320 studies as potentially relevant, and of these, 13 met the inclusion criteria and were included in the analysis. During laparoscopic surgery, use of warmed, humidified CO₂ is associated with a significant increase in intraoperative core temperature (mean temperature change, 0.3°C), when compared with cold, dry CO₂ insufflation_. CONCLUSION: Warmed, humidified CO₂ insufflation during laparoscopic abdominal surgery has been demonstrated to improve intraoperative maintenance of normothermia when compared with cold, dry CO_2.

Cost-utility analysis of the insufflation of warmed humidified carbon dioxide during open and laparoscopic colorectal surgery

BACKGROUND

An evaluation was conducted to estimate the cost-effectiveness of insufflation of warmed humidified CO₂ during open and laparoscopic colorectal surgery compared with usual care from a UK NHS perspective.

METHODS

Decision analytic models were developed for open and laparoscopic surgery. Incremental costs per quality-adjusted life year (QALY) were estimated. The open surgery model used data on the incidence of intra-operative hypothermia and applied risks of complications for hypothermia and normothermia. The laparoscopic surgery model utilised data describing complications directly. Sensitivity analyses were conducted.

RESULTS

Compared with usual care, insufflation of warmed humidified CO₂ dominated. For open surgery, savings of £20 and incremental QALYs of 0.013 were estimated per patient. For laparoscopic surgery, savings of £345 and incremental QALYs of 0.001 per patient were estimated. Results were robust to most sensitivity analyses.

CONCLUSIONS

Considering the current evidence base, the intervention is likely to be cost-effective compared with usual care in patients undergoing colorectal surgery.

Five year follow-up of a randomized controlled trial on warming and humidification of insufflation gas in laparoscopic colonic surgery--impact on small bowel obstruction and oncologic outcomes

Warming and humidification of insufflation gas has been shown to reduce adhesion formation and tumor implantation in the laboratory setting, but clinical evidence is lacking. We aimed to test the hypothesis that warming and humidification of insufflation CO2 would lead to reduced adhesion formation, and improve oncologic outcomes in laparoscopic colonic surgery. This was a 5-year follow-up of a multicenter, double-blinded, randomized, controlled trial investigating warming and humidification of insufflation gas. The study group received warmed (37°C), humidified (98%) insufflation carbon dioxide, and the control group received standard gas (19°C, 0%). All other aspects of patient care were standardized. Admissions for small bowel obstruction were recorded, as well as whether management was operative or nonoperative. Local and systemic cancer recurrence, 5-year overall survival, and cancer specific survival rates were also recorded. Eighty two patients were randomized, with 41 in each arm. Groups were well matched at baseline. There was no difference between the study and control groups in the rate of clinical small bowel obstruction (5.7% versus 0%, P 0.226); local recurrence (6.5% versus 6.1%, P 1.000); overall survival (85.7% versus 82.1%, P 0.759); or cancer-specific survival (90.3% versus 87.9%, P 1.000). Warming and humidification of insufflation CO2 in laparoscopic colonic surgery does not appear to confer a clinically significant long term benefit in terms of adhesion reduction or oncological outcomes, although a much larger randomized controlled trial (RCT) would be required to confirm this. ClinicalTrials.gov Trial identifier: NCT00642005; US National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894, USA.

Heated insufflation with or without humidification for laparoscopic abdominal surgery

BACKGROUND

Intraoperative hypothermia during both open and laparoscopic abdominal surgery may be associated with adverse events. For laparoscopic abdominal surgery, the use of heated insufflation systems for establishing pneumoperitoneum has been described to prevent hypothermia. Humidification of the insufflated gas is also possible. Past studies on heated insufflation have shown inconclusive results with regards to maintenance of core temperature and reduction of postoperative pain and recovery times.

OBJECTIVES

To determine the effect of heated gas insufflation compared to cold gas insufflation on maintaining intraoperative normothermia as well as patient outcomes following laparoscopic abdominal surgery.

SEARCH METHODS

We searched Cochrane Colorectal Cancer Specialised Register (September 2016), the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library 2016, Issue 8), Ovid MEDLINE (1950 to September 2016), Ovid Embase (1974 to September 2016), International Pharmaceutical Abstracts (IPA) (September 2016), Web of Science (1985 to September 2016), Scopus, www.clinicaltrials.gov and the National Research Register (1956 to September 2016). We also searched grey literature and cross references. Searches were limited to human studies without language restriction.

SELECTION CRITERIA

Only randomised controlled trials comparing heated (with or without humidification) with cold gas insufflation in adult and paediatric populations undergoing laparoscopic abdominal procedures were included. We assessed study quality in regards to relevance, design, sequence generation, allocation concealment, blinding, possibility of incomplete data and selective reporting. Two review authors independently selected studies for the review, with any disagreement resolved in consensus with a third co-author.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed screening of eligible studies, data extraction and methodological quality assessment of the trials. We classified a study as low-risk of bias if all of the first six main criteria indicated in the 'Risk of Bias Assessment' table were assessed as low risk. We used data sheets to collect data from eligible studies. We presented results using mean differences for continuous outcomes and relative risks for dichotomous outcomes, with 95% confidence intervals. We used Review Manager (RevMan) 5.3 software to calculate the estimated effects. We took publication bias into consideration and compiled funnel plots.

MAIN RESULTS

We included 22 studies in this updated analysis, including six new trials with 584 additional participants, resulting in a total of 1428 participants. The risk of bias was low in 11 studies, high in one study and unclear in the remaining studies, due primarily to failure to report methodology for randomisation, and allocation concealment or blinding, or both. Fourteen studies examined intraoperative core temperatures among heated and humidified insufflation cohorts and core temperatures were higher compared to cold gas insufflation (MD 0.31 °C, 95% CI, 0.09 to 0.53, I² = 88%, P = 0.005) (low-quality evidence). If the analysis was limited to the eight studies at low risk of bias, this result became non-significant but remained heterogeneous (MD 0.18 °C, 95% CI, -0.04 to 0.39, I²= 81%, P = 0.10) (moderate-quality evidence).In comparison to the cold CO₂ group, the meta-analysis of the heated, non-humidified group also showed no statistically significant difference between groups. Core temperature was statistically, significantly higher in the heated, humidified CO₂ with external warming groups (MD 0.29 °C, 95% CI, 0.05 to 0.52, I² = 84%, P = 0.02) (moderate-quality evidence). Despite the small difference in temperature of 0.31 °C with heated CO₂, this is unlikely to be of clinical significance.For postoperative pain scores, there were no statistically significant differences between heated and cold CO₂, either overall, or for any of the subgroups assessed. Interestingly, morphine-equivalent use was homogeneous and higher in heated, non-humidified insufflation compared to cold insufflation for postoperative day one (MD 11.93 mg, 95% CI 0.92 to 22.94, I² = 0%, P = 0.03) (low-quality evidence) and day two (MD 9.79 mg, 95% CI 1.58 to 18.00, I² = 0%, P = 0.02) (low-quality evidence). However, morphine use was not significantly different six hours postoperatively or in any humidified insufflation groups.There was no apparent effect on length of hospitalisation, lens fogging or length of operation with heated compared to cold gas insufflation, with or without humidification. Recovery room time was shorter in the heated cohort (MD -26.79 minutes, 95% CI -51.34 to -2.25, I² = 95%, P = 0.03) (low-quality evidence). When the one and only unclear-risk study was removed from the analysis, the difference in recovery-room time became non-significant and the studies were statistically homogeneous (MD -1.22 minutes, 95% CI, -6.62 to 4.17, I² = 12%, P = 0.66) (moderate-quality evidence).There were also no differences in the frequency of major adverse events that occurred in the cold or heated cohorts.These results should be interpreted with caution due to some limitations. Heterogeneity of core temperature remained significant despite subgroup analysis, likely due to variations in the study design of the individual trials, as the trials had variations in insufflation gas temperatures (35 ºC to 37 ºC), humidity ranges (88% to 100%), gas volumes and location of the temperature probes. Additionally, some of the trials lacked specific study design information making evaluation difficult.

AUTHORS' CONCLUSIONS

While heated, humidified gas leads to mildly smaller decreases in core body temperatures, clinically this does not account for improved patient outcomes, therefore, there is no clear evidence for the use of heated gas insufflation, with or without humidification, compared to cold gas insufflation in laparoscopic abdominal surgery.

Peritoneal Cytokine Levels Can Predict Anastomotic Leak on the First Postoperative Day

BACKGROUND

Accumulating evidence suggests that peritoneal cytokine concentrations may predict anastomotic leak after colorectal surgery, but previous studies have been underpowered.

OBJECTIVE

We aimed to test this hypothesis by using a larger prospectively collected data set.

DESIGN

This study is an analysis of prospectively collected data.

SETTINGS

This study was conducted at 3 public hospitals in Auckland, New Zealand.

PATIENTS

Patients undergoing colorectal surgery recruited as part of 3 previous randomized controlled trials were included.

MAIN OUTCOME MEASURES

Data on peritoneal and plasma levels of interleukin-6, interleukin-8, interleukin-10, and tumor necrosis factor-α on day 1 after colorectal surgery were reanalyzed to evaluate their predictive value for clinically important anastomotic leak. Area under receiver operating characteristic curve analysis was performed.

RESULTS

A total of 206 patients with complete cytokine data were included. The overall anastomotic leak rate was 8.3%. Concentration levels of peritoneal interleukin-6 and interleukin-10 on day 1 after colorectal surgery were predictive of anastomotic leak (area under receiver operating characteristic curve, 0.72 and 0.74; p = 0.006 and 0.004). Plasma cytokine levels of interleukin-6 were higher on day 1 after colorectal surgery in patients who had an anastomotic leak, but this was a poor predictor of anastomotic leak. Levels of other peritoneal and plasma cytokines were not predictive.

LIMITATIONS

The study was not powered a priori for anastomotic leak prediction. Although the current data do suggest that peritoneal levels of interleukin-6 and interleukin-10 are predictive of leak, the discriminative value in clinical practice remains unclear.

CONCLUSIONS

Peritoneal levels of interleukin-6 and interleukin-10 on day 1 after colorectal surgery can predict clinically important anastomotic leak.

Efficacy of intravenous fluid warming during goal-directed fluid therapy in patients undergoing laparoscopic colorectal surgery: a randomized controlled trial

Objective

To evaluate the clinical efficacy of intravenous (IV) fluid warming in patients undergoing laparoscopic colorectal surgery.

Methods

Adult patients undergoing laparoscopic colorectal surgery were randomly assigned to receive either IV fluids at room temperature (control group) or warmed IV fluids (warm fluids group). Each patient received a standardized goal-directed fluid regimen based on stroke volume variances. Oesophageal temperature was measured at 15 min intervals for 2 h after induction of anaesthesia.

Results

A total of 52 patients were enrolled in the study. The drop in core temperature in the warm fluids group was significantly less than in the control group 2 h after the induction of anaesthesia. This significant difference was seen from 30 min after induction.

Conclusion

IV fluid warming was associated with a smaller drop in core temperature than room temperature IV fluids in laparoscopic colorectal surgery incorporating goal-directed fluid therapy.

Warmed and humidified carbon dioxide for abdominal laparoscopic surgery: meta-analysis of the current literature

BACKGROUND

The creation of a pneumoperitoneum for laparoscopic surgery is performed by the insufflation of carbon dioxide (CO₂). The insufflated CO₂ is generally at room temperature (20-25 °C) and dry (0-5 % relative humidity). However, these physical characteristics could lead to alterations of the peritoneal cavity, leading to operative and postoperative complications. Warming and humidifying the insufflated gas has been proposed to reduce the iatrogenic effects of laparoscopic surgery, such as pain, hypothermia and peritoneal alterations. Two medical devices are currently available for laparoscopic surgery with warm and humidified CO₂.

METHODS

Clinical studies were identified by searching PubMed with keywords relating to humidified and warmed CO₂ for laparoscopic procedures. Analysis of the literature focused on postoperative pain, analgesic consumption, duration of hospital stay and convalescence, surgical techniques and hypothermia.

RESULTS

Bibliographic analyses reported 114 publications from 1977 to 2015, with only 17 publications of clinical interest. The main disciplines focused on were gynaecological and digestive surgery ). Analysis of the studies selected reported only a small beneficial effect of warmed and humidified laparoscopy compared to standard laparoscopy on immediate postoperative pain and per procedure hypothermia. No difference was observed for later postoperative shoulder pain, morphine equivalent daily doses, postoperative body core temperature, recovery room and hospital length of stay, lens fogging and procedure duration.

CONCLUSIONS

Only few beneficial effects on immediate postoperative pain and core temperature have been identified in this meta-analysis. Although more studies are probably needed to close the debate on the real impact of warmed and humidified CO₂ for laparoscopic procedures.

Synthesis and summary of patient-reported outcome measures to inform the development of a core outcome set in colorectal cancer surgery

AIM

Patient-reported outcome (PRO) measures (PROMs) are standard measures in the assessment of colorectal cancer (CRC) treatment, but the range and complexity of available PROMs may be hindering the synthesis of evidence. This systematic review aimed to: (i) summarize PROMs in studies of CRC surgery and (ii) categorize PRO content to inform the future development of an agreed minimum 'core' outcome set to be measured in all trials.

METHOD

All PROMs were identified from a systematic review of prospective CRC surgical studies. The type and frequency of PROMs in each study were summarized, and the number of items documented. All items were extracted and independently categorized by content by two researchers into 'health domains', and discrepancies were discussed with a patient and expert. Domain popularity and the distribution of items were summarized.

RESULTS

Fifty-eight different PROMs were identified from the 104 included studies. There were 23 generic, four cancer-specific, 11 disease-specific and 16 symptom-specific questionnaires, and three ad hoc measures. The most frequently used PROM was the EORTC QLQ-C30 (50 studies), and most PROMs (n = 40, 69%) were used in only one study. Detailed examination of the 50 available measures identified 917 items, which were categorized into 51 domains. The domains comprising the most items were 'anxiety' (n = 85, 9.2%), 'fatigue' (n = 67, 7.3%) and 'physical function' (n = 63, 6.9%). No domains were included in all PROMs.

CONCLUSION

There is major heterogeneity of PRO measurement and a wide variation in content assessed in the PROMs available for CRC. A core outcome set will improve PRO outcome measurement and reporting in CRC trials.

Humidification during laparoscopic surgery: overview of the clinical benefits of using humidified gas during laparoscopic surgery

PURPOSE

The peritoneum is the serous membrane that covers the abdominal cavity and most of the intra-abdominal organs. It is a very delicate layer highly susceptible to damage and it is not designed to cope with variable conditions such as the dry and cold carbon dioxide (CO2) during laparoscopic surgery. The aim of this review was to evaluate the effects caused by insufflating dry and cold gas into the abdominal cavity after laparoscopic surgery.

METHODS

A literature search using the Pubmed was carried out. Articles identified focused on the key issues of laparoscopy, peritoneum, morphology, pneumoperitoneum, humidity, body temperature, pain, recovery time, post-operative adhesions and lens fogging.

RESULTS

Insufflating dry and cold CO2 into the abdomen causes peritoneal damage, post-operative pain, hypothermia and post-operative adhesions. Using humidified and warm gas prevents pain after surgery. With regard to hypothermia due to desiccation, it can be fully prevented using humidified and warm gas. Results relating to the patient recovery are still controversial.

CONCLUSIONS

The use of humidified and warm insufflation gas offers a significant clinical benefit to the patient, creating a more physiologic peritoneal environment and reducing the post-operative pain and hypothermia. In animal models, although humidified and warm gas reduces post-operative adhesions, humidified gas at 32 °C reduced them even more. It is clear that humidified gas should be used during laparoscopic surgery; however, a question remains unanswered: to achieve even greater clinical benefit to the patient, at what temperature should the humidified gas be when insufflated into the abdomen? More clinical trials should be performed to resolve this query.

Systematic review of intervention design and delivery in pragmatic and explanatory surgical randomized clinical trials

BACKGROUND

Surgical interventions are complex, with multiple components that require consideration in trial reporting. This review examines the reporting of details of surgical interventions in randomized clinical trials (RCTs) within the context of explanatory and pragmatic study designs.

METHODS

Systematic searches identified RCTs of surgical interventions published in 2010 and 2011. Included studies were categorized as predominantly explanatory or pragmatic. The extent of intervention details in the reports were compared with the CONSORT statement for reporting trials of non-pharmacological treatments (CONSORT-NPT). CONSORT-NPT recommends reporting the descriptions of surgical interventions, whether they were standardized and adhered to (items 4a, 4b and 4c). Reporting of the context of intervention delivery (items 3 and 15) and operator expertise (item 15) were assessed.

RESULTS

Of 4541 abstracts and 131 full-text articles, 80 were included (of which 39 were classified as predominantly pragmatic), reporting 160 interventions. Descriptions of 129 interventions (80.6 per cent) were provided. Standardization was mentioned for 47 (29.4 per cent) of the 160 interventions, and 22 articles (28 per cent) reported measurement of adherence to at least one aspect of the intervention. Seventy-one papers (89 per cent) provided some information about context. For one-third of interventions (55, 34.4 per cent), some data were provided regarding the expertise of personnel involved. Reporting standards were similar in trials classified as pragmatic or explanatory.

CONCLUSION

The lack of detail in trial reports about surgical interventions creates difficulties in understanding which operations were actually evaluated. Methods for designing and reporting surgical interventions in RCTs, contributing to the quality of the overall study design, are required. This should allow better implementation of trial results into practice.

Development of a risk stratification system for the occurrence of prolonged postoperative ileus after colorectal surgery: a prospective risk factor analysis

BACKGROUND

Management strategies for prolonged postoperative ileus (PPOI) are principally conservative and it is therefore valuable to shift attention to prevention. This study aimed to identify prospectively the perioperative risk factors for the development of PPOI and create a tool to predict its occurrence.

METHODS

Patients undergoing elective colorectal surgery at Auckland District Health Board between September 2012 and June 2014 were enrolled. In total, 92 variables were investigated prospectively with uniform application of a standardized definition of PPOI. Logistic regression and area under receiver operating characteristic curves (AUC) were used to generate risk stratification models.

RESULTS

PPOI occurred in 88 of 327 patients (26.9%). Independent predictors of PPOI were male gender (odds ratio [OR], 3.01), decreasing preoperative albumin (OR, 1.11 per g/L unit), open or converted technique (OR, 6.37 [vs laparoscopic]), increasing wound size (OR, 1.09 [per cm]), operative difficulty (OR, 1.28 [per unit on 10-point Likert scale]), operative bowel handling (OR, 1.38 [per unit on 10-point Likert scale]), red cell transfusion (OR, 1.84 [per unit]), intravenous crystalloid administration (OR, 1.55 [per liter]), and delayed first mobilization (OR, 1.39 [per day]). The I-Score assimilated preoperative and intraoperative variables to generate a score out of 6 with a 7-fold increase in risk from low-risk to high-risk strata and fair predictive capacity (AUC, 0.742; 95% CI, 0.684-0.799).

CONCLUSION

Independent predictors for the development of PPOI have been identified prospectively and used to construct a novel risk stratification model.

A systematic review of outcome reporting in colorectal cancer surgery

AIM

Evaluation of surgery for colorectal cancer (CRC) is necessary to inform clinical decision-making and healthcare policy. The standards of outcome reporting after CRC surgery have not previously been considered.

METHOD

Systematic literature searches identified randomized and nonrandomized prospective studies reporting clinical outcomes of CRC surgery. Outcomes were listed verbatim, categorized into broad groups (outcome domains) and examined for a definition (an appropriate textual explanation or a supporting citation). Outcome reporting was considered inconsistent if results of the outcome specified in the methods were not reported. Outcome reporting was compared between randomized and nonrandomized studies.

RESULTS

Of 5644 abstracts, 194 articles (34 randomized and 160 nonrandomized studies) were included reporting 766 different clinical outcomes, categorized into seven domains. A mean of 14 ± 8 individual outcomes were reported per study. 'Anastomotic leak', 'overall survival' and 'wound infection' were the three most frequently reported outcomes in 72, 60 and 44 (37.1%, 30.9% and 22.7%) studies, respectively, and no single outcome was reported in every publication. Outcome definitions were significantly more often provided in randomized studies than in nonrandomized studies (19.0% vs 14.9%, P = 0.015). One-hundred and twenty-seven (65.5%) papers reported results of all outcomes specified in the methods (randomized studies, n = 21, 61.5%; nonrandomized studies, n = 106, 66.2%; P = 0.617).

CONCLUSION

Outcome reporting in CRC surgery lacks consistency and method. Improved standards of outcome measurement are recommended to permit data synthesis and transparent cross-study comparisons.

Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility

It has been shown, in animal models, that gastrointestinal tract (GIT) motility is influenced by temperature; nevertheless, the basic mechanism governing thermal GIT smooth muscle responses has not been fully investigated. Studies based on physiologically tuned mathematical models have predicted that thermal inhomogeneity may induce an electrochemical destabilization of peristaltic activity. In the present study, the effect of thermal cooling on human colonic muscle strip (HCMS) contractility was studied. HCMSs were obtained from disease-free margins of resected segments for cancer. After removal of the mucosa and serosa layers, strips were mounted in separate chambers. After 30 min, spontaneous contractions developed, which were measured using force displacement transducers. Temperature was changed every hour (37, 34, and 31°C). The effect of cooling was analyzed on mean contractile activity, oscillation amplitude, frequency, and contraction to ACh (10(-5) M). At 37°C, HCMSs developed a stable phasic contraction (~0.02 Hz) with a significant ACh-elicited mean contractile response (31% and 22% compared with baseline in the circular and longitudinal axis, respectively). At a lower bath temperature, higher mean contractile amplitude was observed, and it increased in the presence of ACh (78% and 43% higher than the basal tone in the circular and longitudinal axis, respectively, at 31°C). A simplified thermochemomechanical model was tuned on experimental data characterizing the stress state coupling the intracellular Ca(2+) concentration to tissue temperature. In conclusion, acute thermal cooling affects colonic muscular function. Further studies are needed to establish the exact mechanisms involved to better understand clinical consequences of hypothermia on intestinal contractile activity.

Risk factors for the development of prolonged post-operative ileus following elective colorectal surgery

PURPOSE

Prolonged post-operative ileus (PPOI) increases post-operative morbidity and prolongs hospital stay. An improved understanding of the elements which contribute to the genesis of PPOI is needed in the first instance to facilitate accurate risk stratification and institute effective preventive measures. The aim of this retrospective cohort study was to therefore determine the perioperative risk factors associated with development of PPOI.

METHODS

All elective intra-abdominal operations undertaken by the Colorectal Unit at Auckland District Health Board from 1 January to 31 December 2011 were accessed. Data were extracted for an assortment of patient characteristics and perioperative variables. Cases were stratified by the occurrence of clinician-diagnosed PPOI. Univariate and regression analyses were performed to identify correlates and independent risk factors, respectively.

RESULTS

Two hundred and fifty-five patients were identified of whom 50 (19.6%) developed PPOI. The median duration for PPOI was 4 days with 98% resolving spontaneously with conservative measures. Univariate analysis identified increasing age; procedure type; increasing opiate consumption; elevated preoperative creatinine; post-operative haemoglobin drop, highest white cell count and lowest sodium; and increasing complication grade as significant correlates. Logistic regression found increasing age (OR 1.032, 95% CI 1.004-1.061; p = 0.026) and increasing drop in pre- to post-operative haemoglobin (OR 1.043, 95% CI 1.002-1.085; p = 0.037) as the only independent predictors for developing PPOI. An important limitation of this study was its retrospective nature.

CONCLUSIONS

Increasing age and increasing drop in haemoglobin are independent predictors for developing PPOI. Prospective assessment is required to facilitate more accurate risk factor analysis.

Evidence-based postoperative pain management after laparoscopic colorectal surgery

AIM

The aim of this systematic review was to evaluate the available literature on the management of pain after laparoscopic colorectal surgery.

METHOD

Randomized studies, published in English between January 1995 and July 2011, assessing analgesic and anaesthetic interventions in adults undergoing laparoscopic colorectal surgery, and reporting pain scores, were retrieved from the Embase and MEDLINE databases. The efficacy and adverse effects of the analgesic techniques was assessed. The recommendations were based on procedure-specific evidence from a systematic review and supplementary transferable evidence from other relevant procedures.

RESULTS

Of the 170 randomized studies identified, 12 studies were included. Overall, all approaches including ketorolac, methylprednisolone, intraperitoneal instillation of ropivacaine, intravenous lidocaine infusion, intrathecal morphine and epidural analgesia improved pain relief, reduced opioid requirements and improved bowel function. However, there were significant differences in the study designs and the variables evaluated, precluding quantitative analysis. The L'Abbé plots of the data from the epidural analgesia studies included in this review indicate that the pain scores in the nonepidural groups, although higher than those in the epidural groups, were within an acceptable level (i.e. < 4/10).

CONCLUSION

Infiltration of surgical incisions with local anaesthetic at the end of surgery, systemic steroids, conventional nonsteroidal anti-inflammatory drugs or cyclooxygenase-2-selective inhibitors in combination with paracetamol with opioid used as rescue are recommended. Intravenous lidocaine infusion is recommended, but not as the first line of therapy. However, neuraxial blocks (i.e. epidural analgesia and spinal morphine) are not necessary based on high risk:benefit ratio.

The Surgical Recovery Score correlates with the development of complications following elective colectomy

BACKGROUND

The Surgical Recovery Score (SRS) is a validated, comprehensive recovery assessment tool used to measure functional recovery after major surgery. To further evaluate its clinical applicability, this study investigated whether the SRS correlates with clinical outcomes and the occurrence of complications after elective colectomy.

MATERIALS AND METHODS

We conducted a retrospective review of prospectively collected data for consecutive patients undergoing elective colonic resection within an enhanced recovery program at our institution from September 2008 to September 2011. We administered the 31-item SRS questionnaire preoperatively (baseline) and on postoperative days 1, 3, 7, 14, and 30. We scored individual questionnaires as a percentage of the maximum possible score, with a higher SRS indicating improved functional recovery (range, 17-100). We prospectively recorded clinical outcomes and graded 30-d complications as per the Clavien-Dindo classification. We conducted univariate and logistic regression analysis to determine the correlation of the SRS to the development of complications.

RESULTS

We evaluated 134 patients, 62 of whom developed minor complications (grades 1-2) (46%) and 21 of whom developed major complications (grades 3-5) (16%). The SRS was similar at baseline in the complicated and uncomplicated groups but significantly lower on postoperative days 3, 7, 14, and 30 in patients who developed major complications, and on days 7 and 14 in patients who developed minor complications. In a logistic regression analysis, the SRS on postoperative day 3 was independently associated with the development of any complication, as well as major complications specifically.

CONCLUSIONS

In addition to measuring functional recovery, the SRS closely correlates with the development of complications after elective colectomy and offers a reliable outcome measure to assess overall postoperative recovery.

Laparoscopic-assisted and open high anterior resection within an ERAS protocol

BACKGROUND

Due to potentially superior short-term outcomes compared with open colorectal surgery, laparoscopic surgery is currently being implemented in clinical practice worldwide. In parallel, enhanced recovery after surgery (ERAS) programs are shown to improve postoperative recovery in open colorectal surgery. This study reports outcomes in laparoscopic versus open surgery in conjunction with compliance to the ERAS protocol.

METHODS

The association between surgical approach (laparoscopic or open surgery), compliance to the ERAS protocol, postoperative symptoms, complications, and length of stay after surgery was studied. Between January 2007 to December 2010, 114 consecutive patients underwent elective high anterior resection with laparoscopic-assisted (n = 55) or open resection (n = 59). All clinical data (114 variables) were prospectively recorded.

RESULTS

The overall preoperative ERAS-protocol compliance was 77% for both the laparoscopic and open group. Laparoscopic surgery resulted in shorter total length of stay (median 4 vs. 6 days, p = 0.04), earlier pain control (median 2 vs. 3 days, p = 0.008), shorter need for intravenous infusions, improved mobilization on the first postoperative day (POD1), and lower inflammatory response (CRP (POD1) 54 ± 24 vs. 67 ± 31 mg/l, p = 0.017) compared with open resection. The trends in fewer postoperative complications (9.1 vs. 16.9%; odds ratio (OR) 0.55; 95% confidence interval (CI) 0.17-1.81) and overall postoperative symptoms delaying recovery (20 vs. 30.5%; OR 0.63; 95% CI 0.22-1.34) in laparoscopic surgery were not statistically significant.

CONCLUSIONS

The use of laparoscopy in colorectal surgery within an ERAS protocol results in faster recovery compared with open resection.

Perioperative use of statins in elective colectomy

BACKGROUND

Statins have many beneficial effects and may attenuate the proinflammatory and metabolic stress response to surgery and consequently reduce postoperative morbidity.

OBJECTIVE

This study investigated whether perioperative use of statins improved short-term outcomes after elective colectomy.

DESIGN

This study is a retrospective review of prospectively collected data.

SETTINGS AND PATIENTS

This study was conducted in consecutive patients undergoing elective colonic resection within an enhanced recovery program at a tertiary hospital (Manukau Surgery Centre, Middlemore Hospital, Auckland, New Zealand) from January 2005 to December 2010.

MAIN OUTCOME MEASURES

Complications, hospital stay, and readmissions were recorded for 30 days postoperatively. Postoperative functional recovery was measured by the use of the validated Surgical Recovery Score. Serum proinflammatory cytokines were measured on postoperative day 1.

RESULTS

There were 269 patients; 86 patients were on a statin perioperatively, whereas 183 patients had no statin. Members of the statin group were older (median age, 72 vs 69 years; p = 0.021), included more men (53% vs 40%; p = 0.049), and included a higher number of patients with an ASA score of 3 (55% vs 22%; p < 0.001). Patients on statin therapy had a significantly lower number of anastomotic leaks (1% vs 7%; p = 0.031). However, there was no significant difference in total complications or median hospital stay. The 2 groups had comparable functional recovery, and there was no significant difference in serum cytokine levels.

LIMITATIONS

This retrospective study did not analyze type, duration, or dose of statins given perioperatively.

CONCLUSION

Patients on perioperative statins had greater baseline perioperative risks compared with nonusers, but they achieved equivalent outcomes overall. Statin use was associated with reduced anastomotic leaks. Thus, perioperative statin use may reduce morbidity after elective colectomy, and this finding warrants further investigation.