Ventilatory inefficiency adversely affects outcomes and longer-term survival after planned colorectal cancer surgery.

BACKGROUND: Impaired cardiorespiratory reserve is an accepted risk factor for patients having major surgery. Ventilatory inefficiency, defined by an elevated ratio of minute ventilation to carbon dioxide excretion (VE/VCO2), and measured by cardiopulmonary exercise testing (CPET), is a pathophysiological characteristic of patients with cardiorespiratory disease. We set out to evaluate the prevalence of ventilatory inefficiency in a colorectal cancer surgical population, and its influence on surgical outcomes and long-term cancer survival. METHODS: In this retrospective study of 1375 patients who had undergone preoperative CPET followed by colorectal cancer surgery, we used receiver operating characteristic curve analysis to identify an optimal value of VE/VCO2 associated with 90-day mortality. Binary logistic regression was used to evaluate whether this degree of ventilatory inefficiency was independently associated with decreased survival, both after surgery and in the longer term. RESULTS: We identified an optimal VE/VCO2 >39 cut-off for predicting 90-day mortality; 245 patients (17.8%) had VE/VCO2 >39, of which 138 (10% of total cohort) had no known cardiorespiratory risk factors. Ventilatory inefficiency was independently associated with death at 90-days (8.2% mortality vs 1.9%; adjusted odds ratio [OR], 4.04; 95% confidence interval [CI], 2.09-7.84), with death after unplanned critical care admission (OR=4.45; 95% CI, 1.37-14.46) and with decreased survival at 2 yr (OR=2.21; 95%, 1.49-3.28) and 5 yr (OR=2.87; 95% CI, 1.54-5.37) after surgery. CONCLUSIONS: A significant proportion of patients having colorectal cancer surgery have ventilatory inefficiency observed on CPET, the majority of whom have no history of cardiorespiratory risk factors. This group of patients has significantly decreased survival both after surgery and in the long-term, irrespective of cancer stage. Survival might be improved by formal medical evaluation and intervention in this group.

Predictive Value of C-Reactive Protein for Complications Post-Laparoscopic Roux-En-Y Gastric Bypass.

BACKGROUND: Laparoscopic roux-en-Y gastric bypass (LRYGB) has gained increasing popularity as the primary procedure of choice for the management of patients with morbid obesity. Despite the advances, a few patients will still develop complications and predicting these early complications in morbidly obese patients can prove to be difficult. Radiological investigations have limited diagnostic value and have associated side effects and cost. We propose that C-reactive protein (CRP) is a useful predictor for early postoperative complications. This study aims to determine the ability of CRP taken on postoperative day 1 (POD 1) and 2 to predict occurrence of complications within 30 days of surgery. METHODS: This retrospective observational study selected 183 consecutive patients from the York bariatric database between 01 December 2010 and 23 March 2015. EXCLUSIONS: Patients undergoing dual procedures, conversion to open, and if no postoperative CRP measurement was performed. RESULTS: In total, 138 patients satisfied the inclusion criteria during the study period (median age 44 years [20-68], BMI 50.6 kg/m2 [38.3-62.5]). Fifteen (10.8 %) patients had minor complications (CD of 2) and 8 (5.6 %) had major complications (CD 3 or above). A CRP of greater than 127 mg/L on POD 2 was found to predict complications with 93 % sensitivity and 64 % specificity with diagnostic accuracy 0.82 (95 % confidence interval 0.731-0.908). CONCLUSIONS: In our patients, CRP on POD 2 has been shown to be a good predictor of both minor and major complications and can therefore be used to guide clinicians in making decision as to which patients may need further investigation or who can be safely discharged.

Comparison of esophageal Doppler and plethysmographic variability index to guide intraoperative fluid therapy for low-risk patients undergoing colorectal surgery.

STUDY OBJECTIVE: This study aims to investigate if there is equivalence in volumes of fluid administered when intravenous fluid therapy is guided by Pleth Variability Index (PVI) compared to the established technology of esophageal Doppler in low-risk patients undergoing major colorectal surgery. DESIGN: Randomized controlled trial. SETTING: Operating room. PATIENTS: Forty low-risk patients undergoing elective colorectal surgery. INTERVENTION: Patients were monitored by esophageal Doppler and PVI probes and were randomized to have fluid therapy directed by using one of these technologies, with 250 mL boluses of colloid to maintain a maximal stroke volume, or a PVI of less than 14%. MEASUREMENTS: Absolute volumes of fluid volumes given intraoperatively were measured as were 24 hours fluid volumes. Perioperative measurements of lactate and base excess were recorded as were postoperative complications. MAIN RESULT: There was no significant difference between PVI and esophageal Doppler groups in mean total fluid administered (1286 vs 1520 mL, P=.300) or mean intraoperative fluid balance (+839 v+1145 mL, P=.150). CONCLUSIONS: PVI offers an entirely non-invasive alternative for goal-directed fluid therapy in this group of patients.

Comparison of stroke volume and fluid responsiveness measurements in commonly used technologies for goal-directed therapy.

STUDY OBJECTIVE: To compare stroke volume (SV) and preload responsiveness measurements from different technologies with the esophageal Doppler monitor (EDM). DESIGN: Prospective measurement study. SETTING: Operating room. PATIENTS: 20 ASA physical status 3 patients undergoing vascular, major urological, and bariatric surgery. INTERVENTIONS: Subjects received fluids using a standard Doppler protocol of 250 mL of colloid administered until SV no longer increased by >10%, and again when the measured SV decreased by 10%. MEASUREMENTS: Simultaneous readings of SV, stroke volume variation (SVV) and pulse pressure variation (PPV) from the LiDCOrapid, and SVV from the FloTrac/Vigileo were compared with EDM measurements. The pleth variability index (PVI) also was recorded. MAIN RESULTS: No correlation was seen in percentage SV change as measured by either the LiDCOrapid (r=0.05, P=0.616) or FloTrac (r=0.09, P= 0.363) systems compared with the EDM. Correlation was present between the LiDCOrapid and FloTrac (r=0.515, P<0.0001). Percentage error compared with the EDM was 81% for the FloTrac and 90% for the LiDCOrapid. SVV as measured by LiDCOrapid differed for fluid responders and nonresponders (10% vs 7%; P=0.021). Receiver operator curve analysis to predict a 10% increase in SV from the measured variables showed an area under the curve of 0.57 (95% CI 0.43-0.72) for SVV(FloTrac), 0.64 (95% CI 0.52-0.78) for SVV(LiDCO), 0.61 (95% CI 0.46 -0.76) for PPV, and 0.59 (95% CI 0.46 -0.71) for PVI. CONCLUSIONS: Stroke volume as measured by the FloTrac and LiDCOrapid systems does not correlate with the esphageal Doppler, has poor concordance, and a clinically unacceptable percentage error. The predictive value of the fluid responsiveness parameters is low, with only SVV measured by the LiDCOrapid having clinical utility.

Measuring outcomes after major abdominal surgery during hospitalization: reliability and validity of the Postoperative Morbidity Survey.

BACKGROUND: Measurement of outcomes after major abdominal surgery has traditionally focused on mortality, however the low incidence in elective surgery makes this measure a poor comparator. The Postoperative Morbidity Survey (POMS) prospectively assesses short-term morbidity, and may have clinical utility both as a core outcome measure in clinical trials and quality of care. The POMS has been shown to be a valid outcome measure in a mixed surgical population, however it has not been studied in patients undergoing major abdominal surgery. This study assessed the inter-rater reliability and validity of the POMS in patients undergoing major abdominal surgery. METHODS: Patients undergoing elective major abdominal surgery were visited on postoperative day 1 until discharge by two novice observers who administered the POMS in order to assess inter-rater reliability. Subjects who had previously had the POMS performed prospectively on postoperative days 3 and 5 were identified from a database. The pattern and prevalence of morbidity was analyzed against hospital length of stay (LOS) in order to validate the POMS in this patient group. RESULTS: Fifty one patients were recruited to the inter-rater reliability study giving a total of 263 POMS assessments. Inter-rater reliability showed a 97.7% agreement with a κ coefficient of 0.912 (95% CI: 0.842 to 0.982). On domain analysis percentage agreement was lowest in the gastrointestinal domain (87.5%), whilst correlation was lowest in the wound (κ: 0.04; 95% CI: -1.0 to 1.0) and hematological domains (κ: 0.378; 95% CI: 0.035 to 0.722). All other domains showed at least substantial agreement. POMS assessments were analyzed for postoperative days 3 (n = 258) and 5 (n = 362). The absence or presence of morbidity as measured by the POMS was associated with a hospital LOS of 6 (IQR: 4 to 7) vs. 11 (IQR: 8 to 15) days on postoperative day 3 (P <0.0001), and 7 (IQR: 6 to 10) vs. 13 (IQR: 9 to 19) days on postoperative day 5 (P <0.0001). The presence of any morbidity on postoperative day 5 conferred an odds ratio for a prolonged hospital LOS of 11.9 (95% CI: 5.02 to 11.92). CONCLUSIONS: This study shows that the POMS is both a reliable and valid measure of short-term postoperative morbidity in patients undergoing major abdominal surgery.

Pleth variability index to predict fluid responsiveness in colorectal surgery.

BACKGROUND: Goal-directed fluid therapy during major abdominal surgery may reduce postoperative morbidity. The Pleth Variability Index (PVI), derived from the pulse oximeter waveform, has been shown to be able to predict fluid responsiveness in a number of surgical circumstances. In the present study, we sought to determine whether PVI could predict fluid responsiveness in low-risk colorectal surgery patients who had fluid therapy guided by esophageal Doppler stroke volume measurements. METHODS: Twenty-five low-risk patients undergoing colorectal resection under general anesthesia were studied. Baseline values for esophageal Doppler stroke volume and PVI taken from finger and ear probes were compared with final values after (a) a 500-mL fluid bolus immediately after induction (steady state) and tracheal intubation before the start of the surgery, and (b) 250-mL boluses given in response to a decrease in stroke volume of 10% during surgery as measured by esophageal Doppler (dynamic). Patients were classified into responders and nonresponders based on a stroke volume increase of >10%. RESULTS: Baseline PVI at the finger was significantly higher in responders in both steady-state and intraoperative conditions. In steady state, PVI at both finger and earlobe had significant predictive ability of an increase in stroke volume: area under the curve for finger 0.96 (95% confidence interval [CI], 0.88-1.00; P=0.011) and for earlobe 0.98 (95% CI, 0.93-1.00; P=0.008). In dynamic intraoperative conditions, PVI at the finger predicted increases in stroke volume, area under the curve 0.71 (95% CI, 0.57-0.85; P=0.006), but PVI at the earlobe had no predictive value. CONCLUSIONS: PVI measured at the finger may be able to predict fluid responsiveness during surgery in ventilated patients.

Dopexamine has no additional benefit in high-risk patients receiving goal-directed fluid therapy undergoing major abdominal surgery.

BACKGROUND: Dopexamine has been shown to reduce both mortality and morbidity in major surgery when it is used as part of a protocol to increase oxygen delivery in the perioperative period. A European multicenter study has examined the use of dopexamine in patients undergoing major abdominal surgery, showing a trend toward improved survival and reduced complications in high-risk patients when receiving low-dose dopexamine (0.5 µg · kg(-1) · min(-1)). A reduced oxygen uptake at the anaerobic threshold (AT) has been shown to confer a significant risk of mortality in patients undergoing major abdominal surgery and allows objective identification of a high-risk operative group. In this study, we assessed the effects of low-dose dopexamine on morbidity after major abdominal surgery in patients who were at increased risk by virtue of a reduced AT. METHODS: Patients undergoing elective major colorectal or urological surgery who had an AT of <11 mL · kg(-1) · min(-1) or an AT of 11 to 14 mL · kg(-1) · min(-1) with a history of ischemic heart disease were recruited. Before surgery, a radial arterial cannula was placed and attached to an Edwards Lifesciences FloTrac/Vigileo system for measuring cardiac output. Patients were given a 250-mL bolus of Voluven (6% hydroxyethyl starch 130/0.4 in 0.9% sodium chloride) until the stroke volume no longer increased by 10%, then received either dopexamine (0.5 µg · kg(-1) · min(-1)) or saline 0.9% for 24 hours. During surgery, fluid boluses of Voluven were given if the stroke volume variation was >10%. No crystalloid was given during surgery. A standardized postoperative fluid regime with Hartmann solution was prescribed at 1.5 mL · kg(-1) · h(-1) for 24 hours. The primary outcome measure was postoperative morbidity measured by the Postoperative Morbidity Survey. RESULTS: One hundred twenty-four patients were recruited over a 23-month period. The incidence of morbidity as measured by the Postoperative Morbidity Survey on day 5 was 55% in the control group versus 47% in the dopexamine group (P = 0.14). There was no significant reduction in morbidity on any measured postoperative day. Complication rates, mortality, and hospital length of stay were similar between the 2 groups; however, administration of dopexamine was associated with earlier return of tolerating an enteral diet. CONCLUSION: With the effective use of goal-directed fluid therapy in elective surgical patients, the routine use of dopexamine does not confer an additional clinical benefit.