Association between intraoperative nociception and surgical invasiveness in patients undergoing non-cardiac surgery under general anesthesia: a retrospective cohort study.

There are several indexes of intraoperative nociception during surgery under general anesthesia. Although a higher degree of surgical invasiveness increases intraoperative nociception, an association between the index of intraoperative nociception and severity of surgical invasiveness has not been reported. We hypothesized that there is associations between averaged values of nociceptive response (NR) throughout surgery (mean NR), as the index of intraoperative nociception, and surgical severity codes in the Surgical outcome risk tool (SORT) or procedure risk codes in the Surgical mortality probability model (S-MPM). The primary outcome was the association between mean NR and severity scores of surgical procedure. Hence, a single institutional retrospective cohort study was performed in consecutive patients undergoing non-cardiac surgery under general anesthesia from June 2018 to May 2019. There were significant increases in the three categories of procedure risk in the S-MPM corresponding to the increase in mean NR values in 5090 patients. In the SORT, the highest intensity in the four categories of surgical severity also significantly correlated with the increase in mean NR values. Increasing intensity of intraoperative nociception is likely associated with higher severity codes of surgical invasiveness in prediction models for postoperative morbidity and mortality.

Association between intraoperative nociception and postoperative complications in patients undergoing laparoscopic gastrointestinal surgery.

A higher degree of surgical invasiveness, which increases intraoperative nociception, might induce postoperative complications. Although several nociceptive indices for use during surgery are available in clinical practice, association between intraoperative nociception and postoperative complications has not been reported. An index representing intraoperative nociception, which is the averaged value of Nociceptive Response throughout the surgery (mean NR) was applied to examine the association in the present study. The retrospective study evaluated consecutive adult patients undergoing laparoscopic gastrointestinal surgery, American Society of Anesthesiologists-physical status (ASA-PS) I or II, whose preoperative C-reactive protein level was < 0.3 mg dL-1. We first used ordinal logistic analysis to examine the association between preoperative and intraoperative risk factors and complications graded by the Clavien-Dindo classification. Next, we performed propensity score matched analysis to evaluate the effects of mean NR throughout surgery on postoperative complications. Ordinal logistic analysis (n = 158) revealed that duration of surgery (P < 0.001), mean NR during surgery (P = 0.002), and ASA-PS (P = 0.016) were risk factors for postoperative complications. Then all patients were divided into two propensity score matched groups, based on a mean NR of < 0.85 and ≥ 0.85, with matching for age, ASA-PS, body mass index and duration of surgery. The severity of postoperative complications was significantly higher in the high NR group than in the low NR group (P = 0.005). In conclusion, there was likely an association between intraoperative nociception and postoperative complications in patients without serious preoperative conditions and comorbidities.

Prediction of early C-reactive protein levels after non-cardiac surgery under general anesthesia.

BACKGROUND: Early detection of postoperative increase in C-reactive protein (CRP) correlates with postoperative complications. The present study examined the association between preoperative / intraoperative factors and postoperative CRP levels, with development and validation of a prediction model of early postoperative CRP level, for prophylactic management of postoperative complications in patients undergoing surgery under general anesthesia. MATERIAL AND METHODS: Multivariate regression analysis was retrospectively performed to determine the independent factor of CRP levels on postoperative day (POD) 1 and to develop a prediction model. Validation of the prediction model was prospectively performed. Data from 316 adult patients on perioperative variables were retrospectively obtained in a training cohort in patients undergoing elective non-cardiac surgery. In a validation cohort, 88 patients undergoing mastectomy and 68 patients undergoing laparoscopic colon surgery were prospectively utilized to evaluate the value of the prediction model. Major complications after surgery were defined as the Clavien-Dindo grade IIIa or greater. RESULTS: Duration of surgery, mean nociceptive response (NR) during surgery as intraoperative nociception level, and preoperative CRP level were selected to set up the prediction model of CRP level on POD1 (P < 0.0001). In the validation cohort, the predicted CRP levels on POD1 significantly correlated with the measured CRP after mastectomy (P < 0.0001) and laparoscopic colon surgery (P = 0.0001). Receiver-operating characteristic curve analysis showed that the predicted CRP levels on POD1 was significantly associated with major complications after mastectomy (P = 0.0259) and laparoscopic colon surgery (P = 0.0049). The measured and predicted CRP levels significantly increased in the order of severity of postoperative complications (P < 0.01). CONCLUSION: Increases in duration of surgery, intraoperative nociceptive level and preoperative CRP level were selected to predict early increases in CRP level after non-cardiac surgery under general anesthesia. Predicted CRP levels on POD1 were likely associated with severity of postoperative complications.

Complex effects of continuous vasopressor infusion on fluid responsiveness during liver resection: A randomised controlled trial.

BACKGROUND: Fluid responsiveness is an important factor to consider for fluid volume loading during major surgery. The effect of continuous vasopressor infusion on fluid responsiveness during prolonged major surgery is a concern. OBJECTIVE: We hypothesised that continuous vasopressor infusion during major surgery might not exert significant effects on changes in stroke volume variation (SVV) following fluid bolus infusion, and thereby on fluid responsiveness. DESIGN: Randomised controlled trial. SETTING: University hospital from April 2014 to August 2016. PATIENTS: Patients undergoing liver resection who were randomised to receive continuous intravenous infusion of phenylephrine (P group), norepinephrine (N group), or no vasopressor (C group) (n=17/group). Exclusion criteria were cardiac arrhythmia and severe cardiac, pulmonary or renal dysfunction. INTERVENTION: Patients received 4 ml kg fluid boluses of 6% hydroxyethyl starch solution when SVV was at least 12%. Vasopressors were administered continuously to maintain the systemic vascular resistance index at more than 1900 dyn s cm m. MAIN OUTCOME MEASURES: Cardiac index and SVV were measured using the FloTrac/Vigileo system (Version 4.00). The number of fluid boluses with fluid responsiveness (i.e. >15% increase in cardiac index) was compared between groups using multilevel logistic regression analysis. RESULTS: Numbers of fluid responsive boluses in the C, P and N groups were 12 (14%), 22 (34%) and 19 (27%), respectively. Odds ratios on fluid responsiveness for phenylephrine and norepinephrine compared with the control were 3.65 (97.5% confidence interval, 1.15 to 11.6; P = 0.012) and 2.56 (97.5% confidence interval, 0.82 to 8.00; P = 0.064), respectively. Decreases in SVV after fluid bolus infusion for the P and N groups were comparable with the C group (P = 0.23 and 0.53, respectively). CONCLUSION: Continuous administration of phenylephrine increased fluid responsiveness during liver resection, suggesting complex effects of continuous vasopressor infusion involving changes in cardiac preload and afterload. TRIAL REGISTRATION: UMIN000011024.

Effects of Thoracic Paravertebral Block on Nociceptive Levels After Skin Incision During Video-Assisted Thoracoscopic Surgery.

BACKGROUND Regional anesthesia provides excellent analgesic effects after surgery. However, the effects of regional anesthesia on nociceptive levels during surgery under general anesthesia have not been quantitatively evaluated. To reveal the effects of thoracic paravertebral block (PVB) on nociceptive levels after skin incision during general anesthesia, we performed a retrospective cohort study in patients without serious preoperative conditions or comorbidities undergoing elective video-assisted thoracoscopic surgery (VATS). Nociceptive levels during general anesthesia were calculated using our previously determined Nociceptive Response (NR) equation, which utilizes common hemodynamic parameters. MATERIAL AND METHODS Data on 77 adult patients who underwent VATS from May 2018 to August 2018 were retrospectively obtained from our institutional database. We then performed propensity score matching between patients who received thoracic PVB (PVB group: n=29) and those who did not (Control group: n=48). The averaged values of systolic blood pressure (SBP), heart rate (HR), perfusion index (PI), bispectral index (BIS), and NR from 10 to 5 minutes before skin incision (T0), 5 to 10 minutes (T1), 10 to 15 minutes (T2), 15 to 20 minutes (T3), and 20 to 25 minutes after skin incision (T4), were calculated. RESULTS Twenty-four propensity score-matched patients in each group were analyzed. Mean NR values at T1 and T2 in the PVB group were significantly lower than those in the Control group. SBP, HR, PI, and BIS, however, showed no significant differences between the 2 groups, except for SBP at T2. CONCLUSIONS Thoracic PVB prevented an increase in NR values, which quantitatively represent nociceptive levels under general anesthesia, in patients undergoing VATS.

[Complementary use of central venous oxygen saturation for fluid management in abdominal surgery patients with severely compromised cardiac function: a report of two cases].

Perioperative fluid management for cases with severely compromised cardiac function undergoing major non-cardiac surgery remains a challenge. Dynamic parameters such as stroke volume variation (SVV) and cardiac index obtained by arterial pulse contour analysis may not be sufficient for fluid optimization because individualized optimal parameter values are difficult to determine in cardiac patients. We report two cases of abdominal surgery with severe pre-existing impairment of cardiac function (ejection fraction < 30%) complicated by severe pulmonary and renal dysfunction. In Case 1, because of unreliably high SVV values due to a sudden onset of cardiac arrhythmia, we performed colloid bolus infusion targeting central venous oxygen saturation (ScvO2) above 80%. In Case 2, cardiac index and stroke volume index remained unchanged despite the decrease of SVV after colloid bolus infusion. Infusion of dobutamine was useful for maintaining the ScvO2 above 75% in a rather hypovolemic state (SVV of 10-15%). Our cases suggest that the use of central venous oxygen saturation together with arterial pulse contour analysis may aid decision-making for individualized fluid optimization and use of inotropics in severely compromised cardiac patients undergoing major abdominal surgery.