Stress responses to endoscopic surgery

Cortisol secretory patterns in deep and moderate neuromuscular blockades in laparoscopic surgery under total intravenous anesthesia: A prospective, single-blinded, randomized controlled trial

BACKGROUND

Neuroendocrine stress response induces physiological changes depending on the type of surgery and anesthesia. Although the optimal depth of neuromuscular blockade for reducing this response remains unknown, deep neuromuscular blockade is known to improve the surgical environment. Therefore, we hypothesized that a patient's stress response would be lower in surgical procedures under deep neuromuscular blockade than under moderate neuromuscular blockade.

METHODS

This prospective, randomized, single-blind study enrolled 72 patients who underwent laparoscopic gynecological surgery under general anesthesia and were assigned to group D (deep blockade: target train-of-four 0 and posttetanic count ≥ 1) or group M (moderate blockade: target train-of-four count 1-3). The primary endpoints were changing patterns in cortisol and adrenocorticotrophic hormone levels; the secondary endpoints were patient outcomes, such as hemodynamic variables, serum glucose level, postoperative pain in the postanesthesia care unit, and hospital stay.

RESULTS

The baseline characteristics were comparable between the 67 patients included in the 2 groups (34 in group M and 33 in group D). Cortisol and adrenocorticotrophic hormone levels increased perioperatively in both groups but without significant intergroup differences. Serum glucose level increased perioperatively and decreased postoperatively, but without a significant intergroup difference. Postoperative pain, fentanyl requirement in the postanesthesia care unit, and hospital stay were also comparable.

CONCLUSIONS

Compared with moderate neuromuscular blockade, deep neuromuscular blockade improved the surgical environment without significant intergroup differences in the hormonal stress response.

Effects of Dexmedetomidine on Patients Undergoing Laparoscopic Surgery for Colorectal Cancer

BACKGROUND

Pneumoperitoneum during laparoscopic surgery has a systemic impact on the renal system and might contribute to acute kidney injury or postoperative renal dysfunction. However, effective preventive strategies are still lacking. We aimed to explore the effects of dexmedetomidine (DEX) on kidney and other organ function in patients undergoing elective laparoscopic surgery for colorectal cancer.

MATERIALS AND METHODS

Fifty-six patients were randomly enrolled into the Control or DEX group. The DEX group received 1 µg kg^-1 DEX intravenously within 10 min followed by a maintenance dose of 0.5 µg kg^-1 h^-1 infused until 30 min before closing the peritoneum. In the Control group, 0.9% sodium chloride was administered as a placebo. The primary outcome was serum neutrophil gelatinase-associated lipocalin (NGAL) levels reflecting kidney injury. Secondary outcomes included variables reflecting the kidney, intestinal injury and systemic inflammatory response.

RESULTS

NGAL levels were significantly lower in the DEX group than in the Control group at 1 d and 5 d postoperatively (107.5 ± 55.6 ng mL^-1versus 179.5 ± 78.2 ng mL^-1; 70.3 ± 45.8 ng mL^-1versus 135.2 ± 59.6 ng mL^-1, P < 0.001), while the BUN and Cr levels showed no differences between the groups. Serum DAO activity was significantly lower in the DEX group patients 24 h after surgery. Moreover, I-FABP levels were markedly lower at 2 h and 24 h postoperatively in the DEX group than in the Control group (P < 0.001).

CONCLUSIONS

Perioperative DEX administration may potentially confer kidney and intestinal protection during laparoscopic surgery for colorectal cancer patients.

Animal welfare aspects in respect of the slaughter or killing of pregnant livestock animals (cattle, pigs, sheep, goats, horses)

This scientific opinion addresses animal welfare aspects of slaughtering of livestock pregnant animals. Term of Reference (ToR) 1 requested assessment of the prevalence of animals slaughtered in a critical developmental stage of gestation when the livestock fetuses might experience negative affect. Limited data on European prevalence and related uncertainties necessitated a structured expert knowledge elicitation (EKE) exercise. Estimated median percentages of animals slaughtered in the last third of gestation are 3%, 1.5%, 0.5%, 0.8% and 0.2% (dairy cows, beef cattle, pigs, sheep and goats, respectively). Pregnant animals may be sent for slaughter for health, welfare, management and economic reasons (ToR2); there are also reasons for farmers not knowing that animals sent for slaughter are pregnant. Measures to reduce the incidence are listed. ToR3 asked whether livestock fetuses can experience pain and other negative affect. The available literature was reviewed and, at a second multidisciplinary EKE meeting, judgements and uncertainty were elicited. It is concluded that livestock fetuses in the last third of gestation have the anatomical and neurophysiological structures required to experience negative affect (with 90-100% likelihood). However, there are two different possibilities whether they perceive negative affect. It is more probable that the neurophysiological situation does not allow for conscious perception (with 66-99% likelihood) because of brain inhibitory mechanisms. There is also a less probable situation that livestock fetuses can experience negative affect (with 1-33% likelihood) arising from differences in the interpretation of the fetal electroencephalogram, observed responses to external stimuli and the possibility of fetal learning. Regarding methods to stun and kill livestock fetuses at slaughter (ToR4), sets of scenarios and respective actions take account of both the probable and less probable situation regarding fetal ability for conscious perception. Finally, information was collated on methods to establish the dam's gestational stage based on physical features of livestock fetuses (ToR5).

Is fetal pain a real evidence?

Due to the progress in fetal surgery, it is important to acquire data about fetal pain.

MATERIAL AND METHODS

We performed a Medline research from 1995, matching the following key words: "pain" and "fetus", with the following: "subplate", "thalamocortical", "myelination", "analgesia", "anesthesia", "brain", "behavioral states", "substance p". We focused on: (a) fetal development of nociceptive pathways; (b) fetal electrophysiological, endocrinological and behavioral reactions to stimuli and pain.

RESULTS

We retrieved 217 papers of which 157 were highly informative; some reported similar data or were only case-reports, and were not quoted. Most endocrinological, behavioral and electrophysiological studies of fetal pain are performed in the third trimester, and they seem to agree that the fetus in the 3rd trimester can experience pain. But the presence of fetal pain in the 2nd trimester is less evident. In favor of a 2nd trimester perception of pain is the early development of spino-thalamic pathways (approximately from the 20th week), and the connections of the thalamus with the subplate (approximately from the 23rd week). Against this possibility, some authors report the immaturity of the cortex with the consequent lack of awareness, and the almost continuous state of sleep of the fetus.

CONCLUSIONS

Most studies disclose the possibility of fetal pain in the third trimester of gestation. This evidence becomes weaker before this date, though we cannot exclude its increasing presence since the beginning of the second half of the gestation.

Leptin and perioperative neuroendocrine stress response with two different anaesthetic techniques

BACKGROUND

Stress response to surgery is modulated by several factors, including magnitude of the injury, pain, type of procedure and choice of anaesthesia. Our purpose was to compare intra- and post-operative hormonal changes during total intravenous anaesthesia (TIVA) using propofol and remifentanil vs. sevoflurane anaesthesia in a low stress level surgical model (laparoscopy).

METHODS

We randomly allocated 18 patients undergoing laparoscopic surgery for benign ovarian cysts in two groups to receive either TIVA (group A=9) or sevoflurane anaesthesia (group B=9). Perioperative plasma levels of norepinephrine (NE), epinephrine (E), adrenocorticotropic hormone (ACTH), cortisol and leptin were measured. Blood samples were collected pre-operatively (time 0), 30 min after the beginning of surgery (time 1), after extubation (time 2), and 2 h (time 3) and 4 h after surgery (time 4).

RESULTS

The comparative analysis between the groups shows significantly higher values of NE (P<0.001 at time 1 and P<0.01 at time 3), E (P<0.001 at times 1 and 2; P<0.01 at time 3 and P<0.05 at time 4), ACTH (P<0.001 at times 1 and 2; P<0.05 at time 3) and cortisol (P<0.001 at times 1 and 2; P<0.01 at time 3; P<0.05 at time 4) in group B. The serum values of leptin were not significantly different between the two groups.

CONCLUSION

The choice of anaesthesia does not seem to affect the leptin serum levels but influences the release of stress response markers: ACTH, cortisol, NE and E.

Stress hormone changes in general anesthesia of long duration: isoflurane-nitrous oxide vs sevoflurane-nitrous oxide anesthesia

STUDY OBJECTIVE

There are few comparative studies of stress hormone changes during general anesthesia with long duration between isoflurane-nitrous oxide and sevoflurane-nitrous oxide anesthesia. We investigated perioperative changes of stress hormone in these two anesthetic methods with duration of more than 10 hours.

DESIGN

Prospective study.

SETTING

Operating room and high care unit of a university hospital.

PATIENTS

Twenty patients with ASA physical status I or II for surgery for laryngeal or pharyngeal cancer with expected duration of more than 10 hours.

INTERVENTIONS

Anesthesia was induced with midazolam, thiopental, and vecuronium and was maintained with sevoflurane (sevoflurane group) or isoflurane (isoflurane group) with nitrous oxide 4 L/min in oxygen 2 L/min.

MEASUREMENTS AND MAIN RESULTS

Plasma concentrations of epinephrine, norepinephrine, cortisol, adrenocorticotropic hormone, and anti-diuretic hormone (ADH); serum concentrations of glucagon and insulin; and blood glucose concentration were measured before inhalation of anesthetics, after 5 and 10 hours, and at 1, 6, and 12 hours after the end of inhalation. Epinephrine and norepinephrine concentrations increased continuously during and after surgery in the isoflurane group whereas it increased only after surgery in the sevoflurane group. Both concentrations were higher in the isoflurane group during anesthesia. Cortisol increased continuously whereas adrenocorticotropic hormone increased only during surgery. Anti-diuretic hormone increased with its peak during surgery and the isoflurane group had significantly higher values than the sevoflurane group. Glucose increased both during and after surgery, insulin increased only after surgery, and glucagon decreased during surgery in both groups.

CONCLUSIONS

In inhalation anesthesia with the duration of more than 10 hours, isoflurane-nitrous oxide and sevoflurane-nitrous oxide had the same effects on stress hormone changes except for epinephrine, norepinephrine, and ADH. Epinephrine, norepinephrine, and ADH concentrations were higher in isoflurane-nitrous oxide anesthesia.

The importance of ‘awareness’ for understanding fetal pain

Our understanding of when the fetus can experience pain has been largely shaped by neuroanatomy. However, completion of the cortical nociceptive connections just after mid-gestation is only one part of the story. In addition to critically reviewing evidence for whether the fetus is ever awake or aware, and thus able to truly experience pain, we examine the role of endogenous neuro-inhibitors, such as adenosine and pregnanolone, produced within the feto-placental unit that contribute to fetal sleep states, and thus mediate suppression of fetal awareness. The uncritical view that the nature of presumed fetal pain perception can be assessed by reference to the prematurely born infant is challenged. Rigorously controlled studies of invasive procedures and analgesia in the fetus are required to clarify the impact of fetal nociception on postnatal pain sensitivity and neural development, and the potential benefits or harm of using analgesia in this unique setting.

The effects of remifentanil and alfentanil-based total intravenous anesthesia (TIVA) on the endocrine response to abdominal hysterectomy

STUDY OBJECTIVE

To compare the effects of remifentanil with alfentanil as a part of total intravenous anesthesia (TIVA) on plasma concentrations of cortisol, insulin, and glucose, and hemodynamic responses in patients undergoing abdominal hysterectomy.

DESIGN

Randomized, double-blind study.

SETTING

University hospital.

PATIENTS

24 ASA physical status I female patients scheduled for abdominal hysterectomy.

INTERVENTIONS

Premedicated patients were randomly allocated to receive either remifentanil-propofol (Group R) or alfentanil-propofol (Group A). The loading dose of the study drug was administered over 60 seconds (remifentanil l microg kg(-l) or alfentanil 10 microg kg(-l)) followed by a continuous infusion (remifentanil 0.2 microg kg(-l) min(-l) or alfentanil 0.5 microg kg(-l) min(-l)). In both groups, propofol was administered until loss of consciousness and maintained with a propofol infusion rate of 100 microg kg(-l) min(-l). After induction of anesthesia, all patients were manually ventilated by mask with O2-air mixture for 20 minutes. Then rocuronium 0.6 mg kg(-l) was given for tracheal intubation.

MEASUREMENTS

Mean arterial pressure (MAP) and heart rate (HR) were recorded. Plasma concentrations of cortisol, insulin, and glucose were measured during anesthesia and in the recovery room.

MAIN RESULTS

In Group R, MAP and HR were lower after tracheal intubation and skin incision than in Group A (p < 0.05). Plasma cortisol concentrations decreased from baseline values at 20 minutes after induction, after tracheal intubation, and skin incision in Group R (p < 0.001). Plasma concentrations of cortisol and glucose increased from baseline values at 30 minutes after skin incision and continued to increase in both groups (p = 0.001). Plasma concentrations of cortisol, insulin, and glucose did not differ between groups at all sampling times.

CONCLUSION

Remifentanil provided better hemodynamic stability than alfentanil during anesthesia and surgery. However, both remifentanil and alfentanil had similar effects on the stress endocrine response to abdominal hysterectomy.

Neuroendocrine stress response in patients undergoing benign ovarian cyst surgery by laparoscopy, minilaparotomy, and laparotomy

STUDY OBJECTIVE

To quantify and compare neuroendocrine stress responses during and immediately after surgery by laparoscopy, minilaparotomy, and laparotomy for benign ovarian cysts.

DESIGN

Prospective study (Canadian Task Force classification II-1).

SETTING

Tertiary care university hospital.

PATIENTS

Thirty healthy women with no major diseases and without endocrine disorders.

INTERVENTIONS

Surgery for benign ovarian cysts performed by laparoscopy (10), minilaparotomy (10), or laparotomy (10).

MEASUREMENTS AND MAIN RESULTS

Venous blood samples were collected at fixed times as follows: at 8 A.M. in the ward before transferring the patient to the operating room (time 0), 30 minutes after the beginning of surgery (time 1), at the end of surgery after extubation with the patient awake (time 2), and 2 and 4 hours after the end of surgery (times 3 and 4). We evaluated intraoperative and postoperative variations of the following stress-related markers: norepinephrine (NE), epinephrine (E), adrenocorticotropic hormone (ACTH), human growth hormone (hGH), prolactin (PRL), and cortisol, and postoperative pain. No differences were present in demographic characteristics and operating times in the three groups. No anesthesiologic or surgical complications occurred. Postoperative pain was similar in the laparoscopy and minilaparotomy group but significantly higher in the laparotomy group (p <0.001). Serum levels of markers were not significantly different among the groups at baseline. In the laparoscopy group the increase of hGH was limited to intraoperative time (p <0.05); increases in NE, E, ACTH, and PRL were limited to intraoperative and early postoperative time after extubation (p <0.01), with only PRL persisting with significantly higher levels after the end of surgery (p <0.05). In the minilaparotomy group no increase was detected for hGH, a significant intraoperative increase in cortisol was present (p <0.05), and NE, E, ACTH, and PRL were significantly higher even after the end of surgery (p <0.01). In this group levels of NE, E, and hGH were significantly higher than in the laparoscopy group 2 and 4 hours after the end of surgery (p <0.05). In the laparotomy group significant intraoperative increases were present for all stress markers and persisted until after extubation for ACTH (p <0.01) and to the postoperative period for NE (p <0.01), E (p <0.01), cortisol (p <0.01), PRL (p <0.05), and hGH (p <0.01). In this group levels of NE, E, ACTH, and hGH were significantly higher than those in the laparoscopy group from the beginning (NE p <0.05, E p <0.01, ACTH p <0.05, hGH p <0.01) until after the end of surgery. Comparison of laparotomy and minilaparotomy groups showed the former to have significantly higher plasma levels of E, cortisol, and hGH in intraoperative and postoperative times (p <0.001); significantly higher NE at sampling times 1 and 2 (p <0.001) and time 4 (p <0.01), and no difference at sampling time 3; and ACTH significantly higher only during surgery (p <0.01).

CONCLUSION

Laparoscopic surgery causes minimal activation of stress hormones, which in some instances is confined to the intraoperative period. Minilaparotomy may be a valid alternative to laparoscopy in high-risk patients who cannot tolerate abdominal distention.

Sevoflurane improves the neuroendocrine stress response during laparoscopic pelvic surgery

PURPOSE

Stress response to surgery is modulated by several factors, including magnitude of the injury, type of procedure (e.g., laparoscopy vs laparotomy) and type of anesthesia. Our purpose was to compare intra- and postoperative hormonal changes during isoflurane vs sevoflurane anesthesia, in a clinical model of well defined operative stress (laparoscopic pelvic surgery).

METHOD

In this prospective randomized clinical study, 20 women requiring laparoscopic pelvic surgery for benign ovarian cysts received either a standard isoflurane plus fentanyl (Group A) or sevoflurane plus fentanyl anesthesia (Group B). Blood samples were collected preoperatively, 30 min after the beginning of surgery, at the end of surgery after extubation, and two and four hours after the end of surgery. Intra- and postoperative plasma levels of norepinephrine, epinephrine, adrenocorticotropic hormone (ACTH), cortisol, growth hormone (GH) and prolactin (PRL) were measured.

RESULTS

Catecholamine levels and postoperative pain were similar in both groups. Nonetheless, in comparison to Group A, Group B showed a significant decrease of ACTH, cortisol and GH levels (A vs B at the end of surgery: ACTH 160 +/- 45 vs 100 +/- 40 pg.mL(-1); cortisol 45 +/- 8 vs 23 +/- 7 microg.dL(-1); GH 3 +/- 2 vs 0.8 +/- 0.4 ng.mL(-1); P < 0.001 for all), but enhanced PRL levels (A vs B, at 30 min after the beginning of surgery: 139 +/- 54 vs 185 +/- 22 ng.mL(-1); at the end of surgery: 100 +/- 27 vs 141 +/- 45 ng.mL(-1); P < 0.001 for both).

CONCLUSIONS

In the clinical setting of low stress laparoscopic surgery, the type of volatile anesthetic significantly affected the stress response; the changes associated with sevoflurane suggested a more favourable metabolic and immune response compared to isoflurane.