Performance of the A-line Autoregressive Index (AAI) and of the Bispectral Index (BIS) at assessing depth of short-term sedation following cardiac surgery

Cerebral monitoring in surgical ICU patients

PURPOSE OF REVIEW

To give an overview of cerebral monitoring techniques for surgical ICU patients.

RECENT FINDINGS

As the burden of postsurgical neurological and neurocognitive complications becomes increasingly recognized, cerebral monitoring in the surgical ICU might gain a relevant role in detecting and possibly preventing adverse outcomes. However, identifying neurological alterations in surgical ICU patients, who are often sedated and mechanically ventilated, can be challenging. Various noninvasive and invasive techniques are available for cerebral monitoring, providing an assessment of cortical electrical activity, cerebral oxygenation, blood flow autoregulation, intracranial pressure, and cerebral metabolism. These techniques can be used for the diagnosis of subclinical seizures, the assessment of sedation depth and delirium, the detection of an impaired cerebral blood flow, and the diagnosis of neurosurgical complications.

SUMMARY

Cerebral monitoring can be a valuable tool in the early detection of adverse outcomes in surgical ICU patients, but the evidence is limited, and clear clinical indications are still lacking.

The Effect of Sedation Protocol Using Richmond Agitation-Sedation Scale (RASS) on Some Clinical Outcomes of Mechanically Ventilated Patients in Intensive Care Units: a Randomized Clinical Trial

Introduction: Providing for patients’ comfort and reducing their pain is one of the important tasks of health care professionals in the Intensive Care Unit (ICU). The current study was conducted to determine the effect of a protocol using a Richmond Agitation-Sedation Scale (RASS) on some clinical outcomes of patients under mechanical ventilation (MV) in 2017.

Methods: This single-blind clinical trial was conducted on 79 traumatic patients in the ICU who were randomly allocated into the intervention (N=40) and the control groups (N=39). The sedation was achieved, using a sedation protocol in the intervention group and the routine care in the control group. The clinical outcomes of the patients (duration of MV, length of staying in ICU, final outcome) were measured. As the participants had different lengths of MV and staying in ICU, the data were restructured, and were analyzed, using proper statistical methods.

Results: The patients’ level of sedation in the intervention group was significantly closer to the ideal score of RASS (-1 to +1). The duration of MV was significantly reduced in the intervention group, and the length of stay in the ICU was also significantly shorter. There was no difference in terms of final outcome. The ICU cost in the control group was twice as high as the cost in of the intervention group.

Conclusion: The applied sedation protocol in this study would provide better sedation and could consequently lead to significantly better clinical outcomes, and the cost of caring as a result.

The effect of postoperative positive end-expiratory pressure on postoperative bleeding after off-pump coronary artery bypass grafting

INTRODUCTION

To compare postoperative prophylactic use of two positive end-expiratory pressure (PEEP) levels in order to prevent postoperative bleeding in patients undergoing off-pump coronary artery bypass grafting (CABG) surgery.

MATERIAL AND METHODS

Sixty patients undergoing an elective off-pump CABG operation were included in this prospective, nonrandomized clinical trial. Patients were divided into two groups as receiving either 5 cm H2O (group 1) or 8 cm H2O PEEP (group 2) after the operation until being extubated. Chest tube outputs, use of blood products and other fluids, postoperative hemoglobin levels, accumulation of pleural and pericardial fluid after the removal of chest tubes, and duration of hospital stay were recorded and compared.

RESULTS

Low- and high-pressure PEEP groups did not differ with regard to postoperative chest tube outputs, amounts of transfusions and crystalloid/colloid infusion requirements, or postoperative hemoglobin levels. However, low-pressure PEEP application was associated with significantly higher pleural (92 ±37 ml vs. 69 ±29 ml, p = 0.03) and pericardial fluid (17 ±5 ml vs. 14 ±6 ml, p = 0.04) accumulation. On the other hand, high-pressure PEEP application was associated with significantly longer duration of hospitalization (6.25 ±1.21 days vs. 5.25 ±0.91 days, p = 0.03).

CONCLUSIONS

Prophylactic administration of postoperative PEEP levels of 8 cm H2O, although safe, does not seem to reduce chest-tube output or transfusion requirements in off-pump CABG when compared to the lower level of PEEP. Further studies with larger sample sizes are warranted to confirm the benefits and identify ideal levels of PEEP administration in this group of patients.

Electroacupuncture reduces the dose of midazolam monitored by the bispectral index in critically ill patients with mechanical ventilation: an exploratory study

OBJECTIVE

Electroacupuncture, a modern variation on a traditional Chinese treatment, might be useful for sedation and analgesia. This study aims to investigate whether electroacupuncture can modify the dose of midazolam monitored by the bispectral index (BIS) in critically ill patients with mechanical ventilation.

METHODS

Orotracheally intubated patients undergoing mechanical ventilation were randomly assigned into three groups (groups A, B and C). All patients were given an intravenous infusion of midazolam. Patients in group A received no additional treatment. Patients in group B were given acupuncture without electrical stimulation at acupuncture points GV24 and EX-HN3 (Yintang) for 6 h simultaneously, and patients in group C were given electroacupuncture to the same points as in group B.

RESULTS

Maintaining the BIS between 60 and 80, the hourly mean one dose of midazolam within the first 6 h after sedation in group C was 0.05 (±0.02 mg/kg per hour), which was significantly lower than both group A (0.08 ± 0.03 mg/kg per hour, p<0.001) and group B (0.07 ± 0.01 mg/kg per hour, p<0.021). The doses in groups A and B showed no significant difference. Between-group comparison analysis of hepatic and renal function and severe adverse reactions all showed no significant difference between the three groups.

CONCLUSIONS

Electroacupuncture appears to reduce markedly the dose of sedative drug required in critically ill patients with mechanical ventilation monitored by BIS, without any obvious severe adverse action, and larger studies to confirm the effect are justified.

Changes in BiSpecteral Index (BiS) Values During Cardiopulmonary Bypass (CPB)

BACKGROUND

BiSpecteral Index (BiS) monitoring is standard monitoring regimen in anaesthesia practice. It has also been used in cardiac surgery. It is especially important due to the high incidence of neurological injury or dysfunction that occurs following CPB. This is a retrospective study of 33 cases that were monitored with BiS during the course of coronary artery or valvular surgery, including the period of CPB.

METHODS

Thirty three cases monitored with BiS were studied retrospectively.

RESULT

From the recordings it was determined that the value of BiS which was ranging between 40 to 60 after induction, dropped below 25 at the onset of CPB. This change was statistically significant (p<0.05).

CONCLUSION

This decrease in the BiS value is probably a result of hypo-perfusion and due to clear, oxygen - poor priming fluid reaching the brain. Other periods of hypotension also correlated with the low values of BiS. This cerebral hypoxia which would occur at this time could be the cause of the incidence of neurological dysfunction that is known to occur following CPB.